Science.gov

Sample records for advanced dispersed fringe

  1. Advanced Dispersed Fringe Sensing Algorithm for Coarse Phasing Segmented Mirror Telescopes

    NASA Technical Reports Server (NTRS)

    Spechler, Joshua A.; Hoppe, Daniel J.; Sigrist, Norbert; Shi, Fang; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.

    2013-01-01

    Segment mirror phasing, a critical step of segment mirror alignment, requires the ability to sense and correct the relative pistons between segments from up to a few hundred microns to a fraction of wavelength in order to bring the mirror system to its full diffraction capability. When sampling the aperture of a telescope, using auto-collimating flats (ACFs) is more economical. The performance of a telescope with a segmented primary mirror strongly depends on how well those primary mirror segments can be phased. One such process to phase primary mirror segments in the axial piston direction is dispersed fringe sensing (DFS). DFS technology can be used to co-phase the ACFs. DFS is essentially a signal fitting and processing operation. It is an elegant method of coarse phasing segmented mirrors. DFS performance accuracy is dependent upon careful calibration of the system as well as other factors such as internal optical alignment, system wavefront errors, and detector quality. Novel improvements to the algorithm have led to substantial enhancements in DFS performance. The Advanced Dispersed Fringe Sensing (ADFS) Algorithm is designed to reduce the sensitivity to calibration errors by determining the optimal fringe extraction line. Applying an angular extraction line dithering procedure and combining this dithering process with an error function while minimizing the phase term of the fitted signal, defines in essence the ADFS algorithm.

  2. Experimental Validation of Advanced Dispersed Fringe Sensing (ADFS) Algorithm Using Advanced Wavefront Sensing and Correction Testbed (AWCT)

    NASA Technical Reports Server (NTRS)

    Wang, Xu; Shi, Fang; Sigrist, Norbert; Seo, Byoung-Joon; Tang, Hong; Bikkannavar, Siddarayappa; Basinger, Scott; Lay, Oliver

    2012-01-01

    Large aperture telescope commonly features segment mirrors and a coarse phasing step is needed to bring these individual segments into the fine phasing capture range. Dispersed Fringe Sensing (DFS) is a powerful coarse phasing technique and its alteration is currently being used for JWST.An Advanced Dispersed Fringe Sensing (ADFS) algorithm is recently developed to improve the performance and robustness of previous DFS algorithms with better accuracy and unique solution. The first part of the paper introduces the basic ideas and the essential features of the ADFS algorithm and presents the some algorithm sensitivity study results. The second part of the paper describes the full details of algorithm validation process through the advanced wavefront sensing and correction testbed (AWCT): first, the optimization of the DFS hardware of AWCT to ensure the data accuracy and reliability is illustrated. Then, a few carefully designed algorithm validation experiments are implemented, and the corresponding data analysis results are shown. Finally the fiducial calibration using Range-Gate-Metrology technique is carried out and a <10nm or <1% algorithm accuracy is demonstrated.

  3. Dispersed Fringe Sensing Analysis - DFSA

    NASA Technical Reports Server (NTRS)

    Sigrist, Norbert; Shi, Fang; Redding, David C.; Basinger, Scott A.; Ohara, Catherine M.; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.; Spechler, Joshua A.

    2012-01-01

    Dispersed Fringe Sensing (DFS) is a technique for measuring and phasing segmented telescope mirrors using a dispersed broadband light image. DFS is capable of breaking the monochromatic light ambiguity, measuring absolute piston errors between segments of large segmented primary mirrors to tens of nanometers accuracy over a range of 100 micrometers or more. The DFSA software tool analyzes DFS images to extract DFS encoded segment piston errors, which can be used to measure piston distances between primary mirror segments of ground and space telescopes. This information is necessary to control mirror segments to establish a smooth, continuous primary figure needed to achieve high optical quality. The DFSA tool is versatile, allowing precise piston measurements from a variety of different optical configurations. DFSA technology may be used for measuring wavefront pistons from sub-apertures defined by adjacent segments (such as Keck Telescope), or from separated sub-apertures used for testing large optical systems (such as sub-aperture wavefront testing for large primary mirrors using auto-collimating flats). An experimental demonstration of the coarse-phasing technology with verification of DFSA was performed at the Keck Telescope. DFSA includes image processing, wavelength and source spectral calibration, fringe extraction line determination, dispersed fringe analysis, and wavefront piston sign determination. The code is robust against internal optical system aberrations and against spectral variations of the source. In addition to the DFSA tool, the software package contains a simple but sophisticated MATLAB model to generate dispersed fringe images of optical system configurations in order to quickly estimate the coarse phasing performance given the optical and operational design requirements. Combining MATLAB (a high-level language and interactive environment developed by MathWorks), MACOS (JPL s software package for Modeling and Analysis for Controlled Optical

  4. A dispersed fringe sensor prototype for the Giant Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Frostig, Danielle; McLeod, Brian A.; Kopon, Derek

    2017-01-01

    The Giant Magellan Telescope (GMT) will employ seven 8.4m primary mirror segments and seven 1m secondary mirror segments to achieve the diffraction limit of a 25.4m aperture. One challenge of the GMT is keeping the seven pairs of mirror segments in phase. We present a conceptual opto mechanical design for a prototype dispersed fringe sensor. The prototype, which operates at J-band and incorporates an infrared avalanche photodiode array, will be deployed on the Magellan Clay Telescope to verify the sensitivity and accuracy of the planned GMT phasing sensor.

  5. Performance of Dispersed Fringe Sensor in the Presence of Segmented Mirror Aberrations: Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Basinger, Scott A.; Redding, David C.

    2006-01-01

    Dispersed Fringe Sensing (DFS) is an efficient and robust method for coarse phasing of a segmented primary mirror such as the James Webb Space Telescope (JWST). In this paper, modeling and simulations are used to study the effect of segmented mirror aberrations on the fringe image, DFS signals and DFS detection accuracy. The study has shown due to the pixilation spatial filter effect from DFS signal extraction the effect of wavefront error is reduced and DFS algorithm will be more robust against wavefront aberration by using multi-trace DFS approach. We also studied the JWST Dispersed Hartmann Sensor (DHS) performance in presence of wavefront aberrations caused by the gravity sag and we use the scaled gravity sag to explore the JWST DHS performance relationship with the level of the wavefront aberration. This also includes the effect from line-of-sight jitter.

  6. On the effect of distortion and dispersion in fringe signal of the FG5 absolute gravimeters

    NASA Astrophysics Data System (ADS)

    Křen, Petr; Pálinkáš, Vojtech; Mašika, Pavel

    2016-02-01

    The knowledge of absolute gravity acceleration at the level of 1  ×  10-9 is needed in geosciences (e.g. for monitoring crustal deformations and mass transports) and in metrology for watt balance experiments related to the new SI definition of the unit of kilogram. The gravity reference, which results from the international comparisons held with the participation of numerous absolute gravimeters, is significantly affected by qualities of instruments prevailing in the comparisons (i.e. at present, FG5 gravimeters). Therefore, it is necessary to thoroughly investigate all instrumental (particularly systematic) errors. This paper deals with systematic errors of the FG5#215 coming from the distorted fringe signal and from the electronic dispersion at several electronic components including cables. In order to investigate these effects, we developed a new experimental system for acquiring and analysing the data parallel to the FG5 built-in system. The new system based on the analogue-to-digital converter with digital waveform processing using the FFT swept band pass filter is developed and tested on the FG5#215 gravimeter equipped with a new fast analogue output. The system is characterized by a low timing jitter, digital handling of the distorted swept signal with determination of zero-crossings for the fundamental frequency sweep and also for its harmonics and can be used for any gravimeter based on the laser interferometry. Comparison of the original FG5 system and the experimental systems is provided on g-values, residuals and additional measurements/models. Moreover, advanced approach for the solution of the free-fall motion is presented, which allows to take into account a non-linear gravity change with height.

  7. Method and apparatus for white-light dispersed-fringe interferometric measurement of corneal topography

    NASA Technical Reports Server (NTRS)

    Hochberg, Eric B. (Inventor); Baroth, Edmund C. (Inventor)

    1994-01-01

    An novel interferometric apparatus and method for measuring the topography of aspheric surfaces, without requiring any form of scanning or phase shifting. The apparatus and method of the present invention utilize a white-light interferometer, such as a white-light Twyman-Green interferometer, combined with a means for dispersing a polychromatic interference pattern, using a fiber-optic bundle and a disperser such as a prism for determining the monochromatic spectral intensities of the polychromatic interference pattern which intensities uniquely define the optical path differences or OPD between the surface under test and a reference surface such as a reference sphere. Consequently, the present invention comprises a snapshot approach to measuring aspheric surface topographies such as the human cornea, thereby obviating vibration sensitive scanning which would otherwise reduce the accuracy of the measurement. The invention utilizes a polychromatic interference pattern in the pupil image plane, which is dispersed on a point-wise basis, by using a special area-to-line fiber-optic manifold, onto a CCD or other type detector comprising a plurality of columns of pixels. Each such column is dedicated to a single point of the fringe pattern for enabling determination of the spectral content of the pattern. The auto-correlation of the dispersed spectrum of the fringe pattern is uniquely characteristic of a particular optical path difference between the surface under test and a reference surface.

  8. On-sky demonstration of the GMT dispersed fringe phasing sensor prototype on the Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Kopon, Derek; McLeod, Brian; van Dam, Marcos A.; Bouchez, Antonin; McCracken, Ken; Catropa, Daniel; Podgorski, William; McMuldroch, Stuart; Conder, Alan; Close, Laird; Males, Jared; Morzinski, Katie; Norton, Timothy

    2016-07-01

    The GMT is an aplanatic Gregorian telescope consisting of 7 primary and secondary mirror segments that must be phased to within a fraction of an imaging wavelength to allow the 25.4 meter telescope to reach its diffraction limit. When operating in Laser Tomographic Adaptive Optics (LTAO) mode, on-axis guide stars will not be available for segment phasing. In this mode, the GMT's Acquisition, Guiding, and Wavefront Sensing system (AGWS) will deploy four pickoff probes to acquire natural guide stars in a 6-10 arcmin annular FOV for guiding, active optics, and segment phasing. The phasing sensor will be able to measure piston phase differences between the seven primary/secondary pairs of up to 50 microns with an accuracy of 50 nm using a J-band dispersed fringe sensor. To test the dispersed fringe sensor design and validate the performance models, SAO has built and commissioned a prototype phasing sensor on the Magellan Clay 6.5 meter telescope. This prototype uses an aperture mask to overlay 6 GMT-sized segment gap patterns on the Magellan 6.5 meter primary mirror reimaged pupil. The six diffraction patterns created by these subaperture pairs are then imaged with a lenslet array and dispersed with a grism. An on-board phase shifter has the ability to simulate an arbitrary phase shift within subaperture pairs. The prototype operates both on-axis and 6 arcmin off-axis either with AO correction from the Magellan adaptive secondary MagAO system on or off in order to replicate as closely as possible the conditions expected at the GMT.

  9. Experimental Verification of Dispersed Fringe Sensing as a Segment Phasing Technique using the Keck Telescope

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Ohara, Catherine M.; Chanan, Gary; Troy, Mitch; Redding, Dave C.

    2004-01-01

    Dispersed Fringe Sensing (DFS) is an efficient and robust method for coarse phasing of segmented primary mirrors (from a quarter of a wavelength up to the depth of focus of a single segment, typically several tens of microns). Unlike phasing techniques currently used for ground-based segmented telescopes; this makes it particularly well-suited to the phasing of space-borne segmented telescopes, such as the James Webb Space Telescopes (JWST). In this work we validate DFS by using it to measure the pistons of the segments of one of the Keck telescopes; the results agree with those of the Shack-Hartmann based phasing scheme currently in use at Keck to within 2% over a range of initial piston errors of +/-16 microns.

  10. Experimental Verification of Dispersed Fringe Sensing as a Segment Phasing Technique using the Keck Telescope

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Chanan, Gary; Ohara, Catherine; Troy, Mitchell; Redding, David C.

    2004-01-01

    Dispersed fringe sensing (DFS) is an efficient and robust method for coarse phasing of segmented primary mirrors (from one quarter of a wavelength to as much as the depth of focus of a single segment, typically several tens of microns). Unlike phasing techniques currently used for ground-based segmented telescopes, DFS does not require the use of edge sensors in order to sense changes in the relative heights of adjacent segments; this makes it particularly well suited for phasing of space-borne segmented telescopes, such as the James Webb Space Telescope. We validate DFS by using it to measure the piston errors of the segments of one of the Keck telescopes. The results agree with those of the Shack-Hartmann-based phasing scheme currently in use at Keck to within 2% over a range of initial piston errors of +/-16 (mu)m.

  11. Control system of a dispersed fringe type sensing system of active optics

    NASA Astrophysics Data System (ADS)

    Zhang, Yajun; Zhang, Zhenchao; Zhang, Yong

    2010-07-01

    Active optics plays an important part in segmented mirrors of astronomy telescopes. A dispersed fringe sensor(DFS) using a broadband point source is an efficient method for cophasing and is also highly automated and robust. DFS can estimate the piston between segments only through the spectrum formed by the transmissive grating's dispersion and therefore can replace the edge sensors. So we build an system in our lab to experiment the DFS method. The whole control system of DFS is put forward, including control of displacement actuators and control of shifting the optical fiber. Control of displacement actuators consists in industry computer, HY-6120 I/O card, six stepper motor and other parts. Some theoretical analysis and experiment tests reveal that the actuator could be controlled to 5nm and without backlash by this control strategy. The optical fiber could be shifted out of optical path or shifted in part or whole of optical path so that the spectrum formed by the transmissive grating's dispersion could alter. When six actuators are moving, the piston is changing, and the spectrum is also moving and altering. And the whole control of DFS system is constructed now and seems well. Further test and experiment will be carry out.

  12. Performance of Dispersed Fringe Sensor in the Presence of Segmented Mirror Aberrations - Modeling and Simulations

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Basinger, Scott A.; Redding, David C.

    2006-01-01

    Wavefront aberrations will lower the DFS fringe visibility and DFS signal SNR. The specific effect of wavefront aberration on DFS depends on the aberration type. Due to the "pixel spatial filter" effect the extracted DFS signal can tolerate moderate amount of wavefront aberrations..By averaging piston detection results from multiple traces extracted from fringe images DFS can further increase its robustness against wavefront aberration. Line-of-sight jitter can cause significant loss of fringe visibility will affect more on the aberrated system..Modeling results have shown that gravity sag on the JWST segment mirror during I&T will lower the DHS fringe visibility by factor of 2-3X and lower the DHS signal intensity by factor of approx.5X. Under gravity sag the RMS DHS detection error approx. 100 nm.

  13. Temporal and spatial variability in the flow and dispersal of suspended-sediment on a fringing reef flat, Molokai, Hawaii

    USGS Publications Warehouse

    Presto, M.K.; Ogston, A.S.; Storlazzi, C.D.; Field, M.E.

    2006-01-01

    A multi-year study was conducted on a shallow fringing reef flat on Molokai, Hawaii to determine the temporal and spatial dispersal patterns of terrigenous suspended sediment. During this study, trade-wind conditions existed for the majority of the year on the reef flat. The trade-wind conditions produced strong currents and resuspended moderate amounts of sediment on the reef flat on a daily basis during the year of study, resulting in an overwhelming contribution to the total sediment flux. The magnitude and direction of the trade winds relative to the orientation of the coastline, the shallow-relief and broad morphology, and tidal elevation, provided the primary control of the physical processes that resuspended and transported sediment on the reef flat over the period of record. Spatial data indicate that much of the terrigenous sediment resuspended on the reef flat is transported predominantly alongshore and is confined to the inner- to mid-reef flat. Evidence for the limited across-shore mixing and transport is provided by the dominantly alongshore wind-driven currents during trade-wind conditions and the well-defined across-shore gradient in percentage calcium carbonate of the suspended sediment. Regions of slightly offshore suspended-sediment transport along the reef flat can be attributed to the circulation pattern set up by the interaction between the trade winds, coastal morphology, and anthropogenic coastal structures (i.e., fish ponds and wharf). The regions in which sediment were seen to move offshore provide the strongest link between the sediment dynamics on reef flat and fore reef, and qualitatively appears to be correlated with low coral coverage on the fore reef. ?? 2005 Elsevier Ltd. All rights reserved.

  14. Temporal and spatial variability in the flow and dispersal of suspended-sediment on a fringing reef flat, Molokai, Hawaii

    NASA Astrophysics Data System (ADS)

    Presto, M. K.; Ogston, A. S.; Storlazzi, C. D.; Field, M. E.

    2006-03-01

    A multi-year study was conducted on a shallow fringing reef flat on Molokai, Hawaii to determine the temporal and spatial dispersal patterns of terrigenous suspended sediment. During this study, trade-wind conditions existed for the majority of the year on the reef flat. The trade-wind conditions produced strong currents and resuspended moderate amounts of sediment on the reef flat on a daily basis during the year of study, resulting in an overwhelming contribution to the total sediment flux. The magnitude and direction of the trade winds relative to the orientation of the coastline, the shallow-relief and broad morphology, and tidal elevation, provided the primary control of the physical processes that resuspended and transported sediment on the reef flat over the period of record. Spatial data indicate that much of the terrigenous sediment resuspended on the reef flat is transported predominantly alongshore and is confined to the inner- to mid-reef flat. Evidence for the limited across-shore mixing and transport is provided by the dominantly alongshore wind-driven currents during trade-wind conditions and the well-defined across-shore gradient in percentage calcium carbonate of the suspended sediment. Regions of slightly offshore suspended-sediment transport along the reef flat can be attributed to the circulation pattern set up by the interaction between the trade winds, coastal morphology, and anthropogenic coastal structures (i.e., fish ponds and wharf). The regions in which sediment were seen to move offshore provide the strongest link between the sediment dynamics on reef flat and fore reef, and qualitatively appears to be correlated with low coral coverage on the fore reef.

  15. Localization of Interference Fringes.

    ERIC Educational Resources Information Center

    Simon, J. M.; Comastri, Silvia A.

    1980-01-01

    Discusses a proof for determining the localized fringes position arrived at when one considers the interference of two extended sources when one is able to observe fringes only at certain points in space. Shows how the localized fringes may be found in a device used to observe Newton's rings. (Author/CS)

  16. Controlling exfoliation in order to minimize damage during dispersion of long SWCNTs for advanced composites

    PubMed Central

    Yoon, Howon; Yamashita, Motoi; Ata, Seisuke; Futaba, Don N.; Yamada, Takeo; Hata, Kenji

    2014-01-01

    We propose an approach to disperse long single-wall carbon nanotubes (SWCNTs) in a manner that is most suitable for the fabrication of high-performance composites. We compare three general classes of dispersion mechanisms, which encompass 11 different dispersion methods, and we have dispersed long SWCNTs, short multi-wall carbon nanotubes, and short SWCNTs in order to understand the most appropriate dispersion methods for the different types of CNTs. From this study, we have found that the turbulent flow methods, as represented by the Nanomizer and high-pressure jet mill methods, produced unique and superior dispersibility of long SWCNTs, which was advantageous for the fabrication of highly conductive composites. The results were interpreted to imply that the biaxial shearing force caused an exfoliation effect to disperse the long SWCNTs homogeneously while suppressing damage. A conceptual model was developed to explain this dispersion mechanism, which is important for future work on advanced CNT composites. PMID:24469607

  17. Air modeling: Air dispersion models; regulatory applications and technological advances

    SciTech Connect

    Miller, M.; Liles, R.

    1995-09-01

    Air dispersion models are a useful and practical tool for both industry and regulatory agencies. They serve as tools for engineering, permitting, and regulations development. Their cost effectiveness and ease of implementation compared to ambient monitoring is perhaps their most-appealing trait. Based on the current momentum within the U.S. EPA to develop better models and contain regulatory burdens on industry, it is likely that air dispersion modeling will be a major player in future air regulatory initiatives.

  18. Advanced oxide dispersion strengthened sheet alloys for improved combustor durability

    NASA Technical Reports Server (NTRS)

    Henricks, R. J.

    1981-01-01

    Burner design modifications that will take advantage of the improved creep and cyclic oxidation resistance of oxide dispersion strengthened (ODS) alloys while accommodating the reduced fatigue properties of these materials were evaluated based on preliminary analysis and life predictions, on construction and repair feasibility, and on maintenance and direct operating costs. Two designs - the film cooled, segmented louver and the transpiration cooled, segmented twin Wall - were selected for low cycle fatigue (LCF) component testing. Detailed thermal and structural analysis of these designs established the strain range and temprature at critical locations resulting in predicted lives of 10,000 cycles for MA 956 alloy. The ODs alloys, MA 956 and HDA 8077, demonstrated a 167 C (300 F) temperature advantage over Hastelloy X alloy in creep strength and oxidation resistance. The MA 956 alloy was selected for mechanical property and component test evaluations. The MA 956 alloy was superior to Hastelloy X in LCF component testing of the film cooled, segmented louver design.

  19. Dispersed Remnants of a Northeast Pacific Fringing Arc: Upper Paleozoic Terranes of Permian McCLOUD Faunal Affinity, Western U.S.

    NASA Astrophysics Data System (ADS)

    Miller, M. Meghan

    1987-12-01

    Two fragmentary, subparallel belts of terranes within the western North American Cordillera contain upper Paleozoic rocks and are characterized by contrasting lithotectonic assemblages and contrasting Permian faunal affinity. These two belts are (A) volcanic-arc related successions of Permian McCloud faunal affinity (McCloud belt) and (B) subduction-related accretionary complexes of Permian Tethy an faunal affinity (Cache Creek belt). This paper supports the hypothesis that the fragmentary terranes of the McCloud belt once constituted parts of a northeast Pacific fringing-arc system and, in constrast to some earlier interpretations, concludes that the volcanic arc evolved above an eastward dipping subduction zone. The absolute distance between this arc and western North America during the late Paleozoic cannot be constrained, however, there is little evidence to suggest closure of a major (>10³ km) ocean basin or protracted periods of westward dipping subduction. Parts of Devonian to Permian volcanic island arc sequences of the western U.S. Cordillera are represented in the northern Sierra, eastern Klamath, Bilk Creek, Grindstone, and Chilliwack terranes. These scattered volcanic arc remnants share several fundamental characteristics: (1) The sequences were constructed across continental-affinity basement assemblages. (2) They underwent similar tectonic evolution during late Paleozoic time, such as coeval pulses in volcanism and related depositional histories. (3) They contain Early Permian McCloud-type fauna, of distinctive biogeographic affinity. (4) McCloud belt terranes are spatially and possibly genetically related to westward lying accretionary complexes of the Cache Creek belt which contain fragments of Upper Triassic blueschist and Permian limestone blocks bearing Tethyan Permian fusulinids and corals. Based on the presence of distinctive Early Permian McCloud fauna, the island arc remnants discussed in this paper are referred to as the McCloud belt. The

  20. Advanced liquefaction using coal swelling and catalyst dispersion techniques

    SciTech Connect

    Curtis, C.W. ); Gutterman, C. ); Chander, S. )

    1992-08-26

    Research in this project centers upon developing a new approach to the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates all aspects of the coal liquefaction process including coal selection, pretreatment, coal swelling with catalyst impregnation, coal liquefaction experimentation, product recovery with characterization, alternate bottoms processing, and a technical assessment including an economic evaluation. The project is being carried out under contract to the United States Department of Energy. On May 28, 1992, the Department of Energy authorized starting the experimental aspects of this projects; therefore, experimentation at Amoco started late in this quarterly report period. Research contracts with Auburn University, Pennsylvania State University, and Foster Wheeler Development Corporation were signed during June, 1992, so their work was just getting underway. Their work will be summarized in future quarterly reports. A set of coal samples were sent to Hazen Research for beneficiation. The samples were received and have been analyzed. The literature search covering coal swelling has been up-dated, and preliminary coal swelling experiments were carried out. Further swelling experimentation is underway. An up-date of the literature on the liquefaction of coal using dispersed catalysts is nearing completion; it will be included in the next quarterly report.

  1. Dispersal

    USGS Publications Warehouse

    Clobert, J.; Danchin, E.; Dhondt, A.A.; Nichols, J.D.

    2001-01-01

    The ability of species to migrate and disperse is a trait that has interested ecologists for many years. Now that so many species and ecosystems face major environmental threats from habitat fragmentation and global climate change, the ability of species to adapt to these changes by dispersing, migrating, or moving between patches of habitat can be crucial to ensuring their survival. This book provides a timely and wide-ranging overview of the study of dispersal and incorporates much of the latest research. The causes, mechanisms, and consequences of dispersal at the individual, population, species and community levels are considered. The potential of new techniques and models for studying dispersal, drawn from molecular biology and demography, is also explored. Perspectives and insights are offered from the fields of evolution, conservation biology and genetics. Throughout the book, theoretical approaches are combined with empirical data, and care has been taken to include examples from as wide a range of species as possible.

  2. Development of Advanced Oxide Dispersion Strengthened Tungsten Heavy Alloy for Penetrator Application

    DTIC Science & Technology

    2005-09-30

    preparation, sintering, cyclic heat-treatment, swaging , and annealing processes, on microstructures and static/dynamic mechanical properties of ODS tungsten ... tungsten / tungsten contiguity. The swaging and annealing processes of ODS tungsten heavy alloy increase the tensile strength with decreasing the...Final Report for 2nd Year Contract of AOARD 034032 Development of Advanced Oxide Dispersion Strengthened Tungsten Heavy Alloy for

  3. Finding the Biotic Fringe

    NASA Astrophysics Data System (ADS)

    Shock, E.

    2014-12-01

    The deepest extent of inhabited rock, known as the biotic fringe, is determined by the interplay of geochemical and biochemical reaction rates. As a consequence it is unlikely that a single parameter, such as temperature, will be generally diagnostic. More probably, shifting combinations of compositional factors, together with temperature and pressure changes, will determine the position and dynamic movements of the biotic fringe. As an example, during serpentinization the biotic fringe may be determined by the depletion of carbon through carbonate precipitation or abiotic organic synthesis at mineral surfaces at temperatures and pressures that are readily inhabited elsewhere. During other weathering, diagenetic and alteration processes, the transition from sterile to populated may be determined by supply rates of reductants, oxidants, nutrients, or their diverse combinations. Where geochemical composition and mineral catalysts permit rapid abiotic organic synthesis and redox equilibration, microbes are unlikely to be able to compete. This is especially true if such conditions inhibit the function of enzymatic catalysts. As abiotic rates slow, opportunities for catalysis emerge as can the biotic fringe where enzymes can function effectively. There are many ways to turn this conceptual model into one that makes quantitative predictions. Rates of many abiotic redox and organic synthesis reactions are amenable to experimental study, and parallel biotic rate experiments yield particularly useful results. Likewise, determining how enzymes are inactivated at the limits of their function will add explicit biochemical constraints. Exploring for the biotic fringe in the subsurface involves using compositional data to evaluate apparent temperatures of equilibration that reveal anomalous approaches to redox equilibrium at conditions where abiotic rates are insufficient. Meanwhile, sampling the inhabitants of the biotic fringe will reveal surprising extents of enzyme behavior.

  4. Interferometers without fringe patterns

    NASA Astrophysics Data System (ADS)

    Garcia-Marquez, Jorge L.; Malacara-Hernandez, Daniel; Malacara-Doblado, Daniel

    1995-08-01

    There are some optical arrangements closely resembling interferometric configurations. These, however, do not produce fringe patterns. An important characteristic of this device is that they do not have two different outputs with complementary patterns, but only one. Two of these configurations are described.

  5. Interferometers without observable fringes

    NASA Astrophysics Data System (ADS)

    Garcia-Marquez, Jorge L.; Malacara-Hernandez, Daniel; Malacara-Doblado, Daniel

    1997-10-01

    There are some optical arrangements that closely resemble interferometric configurations but do not produce fringe patterns. An important characteristics of these devices is that they do not have two different outputs with complementary patterns, but only one. Some of these interferometers are described here, pointing out their common properties and differences. It is shown that if we open the second output, both complementary patterns will appear.

  6. Advances in Analytical and Numerical Dispersion Modeling of Pollutants Releasing from an Area-source

    NASA Astrophysics Data System (ADS)

    Nimmatoori, Praneeth

    The air quality near agricultural activities such as tilling, plowing, harvesting, and manure application is of main concern because they release fine particulate matter into the atmosphere. These releases are modeled as area-sources in the air quality modeling research. None of the currently available dispersion models relate and incorporate physical characteristics and meteorological conditions for modeling the dispersion and deposition of particulates emitting from such area-sources. This knowledge gap was addressed by developing the advanced analytical and numerical methods for modeling the dispersion of particulate matter. The development, application, and evaluation of new dispersion modeling methods are discussed in detail in this dissertation. In the analytical modeling, a ground-level area source analytical dispersion model known as particulate matter deposition -- PMD was developed for predicting the concentrations of different particle sizes. Both the particle dynamics (particle physical characteristics) and meteorological conditions which have significant effect on the dispersion of particulates were related and incorporated in the PMD model using the formulations of particle gravitational settling and dry deposition velocities. The modeled particle size concentrations of the PMD model were evaluated statistically after applying it to particulates released from a biosolid applied agricultural field. The evaluation of the PMD model using the statistical criteria concluded effective and successful inclusion of dry deposition theory for modeling particulate matter concentrations. A comprehensive review of analytical area-source dispersion models, which do not account for dry deposition and treat pollutants as gases, was conducted and determined three models -- the Shear, the Parker, and the Smith. A statistical evaluation of these dispersion models was conducted after applying them to two different field data sets and the statistical results concluded that

  7. Advances in drug delivery and medical imaging using colloidal lyotropic liquid crystalline dispersions.

    PubMed

    Mulet, Xavier; Boyd, Ben J; Drummond, Calum J

    2013-03-01

    The overarching goal of this feature article is to review the recent developments in the field of drug delivery specifically involving colloidal lyotropic liquid crystalline dispersions. The development of advanced particles for drug delivery applications is regarded as the next necessary step in the advancement of nanomedicine. An outline of the state of the art in preparation and application of self-assembled nanoparticles to drug delivery and medical imaging is presented. The basic concepts for controlling the nature of the internal structure of particles by tuning the self-assembly properties of small molecule amphiphiles is covered. Theranostics is an exciting emerging area for this colloidal material class, and the types of therapeutic compounds and medical imaging agents that can be incorporated as well as their methods of preparation are described. The stabilisation and biocompatibility of the colloidal dispersions are also discussed. Finally an overview of lesion-specific active and passive targeting is presented. Exploiting such a multi-functional drug delivery platform is essential to not only the next generation delivery of bioactive molecules but also in the creation of new diagnostic tools.

  8. They shall wear fringes.

    PubMed

    Sugar, M

    1999-01-01

    The multiple functions of clothes include utility, protection, rivalry, disguise, camouflage, display for seduction purposes, aggression, totemism, and status. Here the focus is on a decorative and distinctive hierarchical aspect of ancient dress, the tsitsit or fringes, whose original function is long absent, but that has endured for 3,500 years in Judaism. The beginning of their use beyond the totemic appears related to issues of changing identity from slavery to liberty, endowing noble status, exhibitionism, a symbol of identity, identification with the aggressor, a talisman, and potency. It is conceptualized that they became a symbol, or a specifier, that helped promote group cohesion in ex-slaves who were frightened, dependent, anxious, and not hopeful about their future. The tsitsit aided the development of a new identity and made all Israelites equal and noble to the observer. The durability of this symbol to the present is evident in its daily wear, as an accompaniment to daily prayers, as well as in its use as a burial shroud for males. It appears that the tsitsit have additional multiple functions. These are the promise of oral and genital satisfaction, and the pleasure of the after-life, superego warnings and control of sexual impulses, protection, survival value, and affirmation. Since they offer sublimation with acceptable gratification of instincts, the tsitsit have become ritualized and endure.

  9. Fringe Formation in Dual-Hologram Interferometry

    NASA Technical Reports Server (NTRS)

    Burner, A. W.

    1989-01-01

    A first order geometrical optics treatment of holograms combined with the generation of interference fringes by two point sources is used to describe reference fringe formation in non-diffuse dual-hologram interferometry.

  10. Modular digital holographic fringe data processing system

    NASA Technical Reports Server (NTRS)

    Downward, J. G.; Vavra, P. C.; Schebor, F. S.; Vest, C. M.

    1985-01-01

    A software architecture suitable for reducing holographic fringe data into useful engineering data is developed and tested. The results, along with a detailed description of the proposed architecture for a Modular Digital Fringe Analysis System, are presented.

  11. Interference fringes measurement based on Hough transform

    NASA Astrophysics Data System (ADS)

    Bai, Fuzhong; Rao, Changhui

    2008-12-01

    The paper firstly discusses the derivation of interference fringes and FFT method that is a conventional method for measuring fringes with equal spacing. And then, a new method for measuring the interference line fringes is presented. On the basis of Hough transform and digital image processing technology, this method accomplishes fringes image preprocessing (i.e., fringes skeletonizing) and fringes spacing measurement. It has been shown, with both theoretical analysis and experimental measurements, that this method is a universal method for fringes measurement and has more remarkable advantage than the FFT method because of the application of the former not being limited by some regulations such as equidistant fringes and sampling length, and so on. In addition, it also holds a good noise rejection capability and great reliability.

  12. Color Fringes Bordering Black Stripes at the Bottom of a Swimming Pool

    NASA Astrophysics Data System (ADS)

    Fuster, Gonzalo; Rojas, Roberto; Slüsarenko, Viktor

    2016-09-01

    We have observed a nice example of chromatic dispersion due to refraction in water, in the form of color fringes bordering the black stripes that exist at the bottom of a swimming pool. Here we give a qualitative description of the phenomenon, explaining the role of the black stripes and the dispersive index of refraction of water.

  13. Color Fringes Bordering Black Stripes at the Bottom of a Swimming Pool

    ERIC Educational Resources Information Center

    Fuster, Gonzalo; Rojas, Roberto; Slüsarenko, Viktor

    2016-01-01

    We have observed a nice example of chromatic dispersion due to refraction in water, in the form of color fringes bordering the black stripes that exist at the bottom of a swimming pool. Here we give a qualitative description of the phenomenon, explaining the role of the black stripes and the dispersive index of refraction of water.

  14. College and University Fringe Benefits

    ERIC Educational Resources Information Center

    Middleditch, Leigh B., Jr.

    1973-01-01

    As the number and level of fringe benefits increases, particularly in the retirement sphere, institutions must keep in mind that today's commitment will be felt in tomorrow's budget. The range of employee benefits available are analyzed with regard to cost: unfunded benefits (vacations, leave), government programs, insurance, retirement plans, and…

  15. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OF SEX § 1604.9 Fringe benefits. (a) “Fringe benefits,” as used herein, includes medical, hospital... discriminate between men and women with regard to fringe benefits. (c) Where an employer conditions benefits... women employees, and that “head of household” or “principal wage earner” status bears no relationship...

  16. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... OF SEX § 1604.9 Fringe benefits. (a) “Fringe benefits,” as used herein, includes medical, hospital... discriminate between men and women with regard to fringe benefits. (c) Where an employer conditions benefits... women employees, and that “head of household” or “principal wage earner” status bears no relationship...

  17. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this...

  18. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this...

  19. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this...

  20. Laser fringe anemometry for aero engine components

    NASA Technical Reports Server (NTRS)

    Strazisar, A. J.

    1986-01-01

    Advances in flow measurement techniques in turbomachinery continue to be paced by the need to obtain detailed data for use in validating numerical predictions of the flowfield and for use in the development of empirical models for those flow features which cannot be readily modelled numerically. The use of laser anemometry in turbomachinery research has grown over the last 14 years in response to these needs. Based on past applications and current developments, this paper reviews the key issues which are involved when considering the application of laser anemometry to the measurement of turbomachinery flowfields. Aspects of laser fringe anemometer optical design which are applicable to turbomachinery research are briefly reviewed. Application problems which are common to both laser fringe anemometry (LFA) and laser transit anemometry (LTA) such as seed particle injection, optical access to the flowfield, and measurement of rotor rotational position are covered. The efficiency of various data acquisition schemes is analyzed and issues related to data integrity and error estimation are addressed. Real-time data analysis techniques aimed at capturing flow physics in real time are discussed. Finally, data reduction and analysis techniques are discussed and illustrated using examples taken from several LFA turbomachinery applications.

  1. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    SciTech Connect

    Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole

    2012-03-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  2. Quantum interference fringes beating the diffraction limit.

    PubMed

    Kawabe, Yoshio; Fujiwara, Hideki; Okamoto, Ryo; Sasaki, Keiji; Takeuchi, Shigeki

    2007-10-17

    Spatially formed two-photon interference fringes with fringe periods smaller than the diffraction limit are demonstrated. In the experiment, a fringe formed by two-photon NOON states with wavelength lambda=702.2 nm is observed using a specially developed near-field scanning optical microscope probe and two-photon detection setup. The observed fringe period of 328.2 nm is well below the diffraction limit (351 nm = lambda /2). Another experiment with a path-length difference larger than the coherent length of photons confirms that the observed fringe is due to two-photon interference.

  3. Dispersing perylene diimide/SWCNT hybrids: structural insights at the molecular level and fabricating advanced materials.

    PubMed

    Tsarfati, Yael; Strauss, Volker; Kuhri, Susanne; Krieg, Elisha; Weissman, Haim; Shimoni, Eyal; Baram, Jonathan; Guldi, Dirk M; Rybtchinski, Boris

    2015-06-17

    The unique properties of carbon nanotubes (CNT) are advantageous for emerging applications. Yet, the CNT insolubility hampers their potential. Approaches based on covalent and noncovalent methodologies have been tested to realize stable dispersions of CNTs. Noncovalent approaches are of particular interest as they preserve the CNT's structures and properties. We report on hybrids, in which perylene diimide (PDI) amphiphiles are noncovalently immobilized onto single wall carbon nanotubes (SWCNT). The resulting hybrids were dispersed and exfoliated both in water and organic solvents in the presence of two different PDI derivatives, PP2b and PP3a. The dispersions were investigated using cryogenic transmission electron microscopy (cryo-TEM), providing unique structural insights into the exfoliation. A helical arrangement of PP2b assemblies on SWCNTs dominates in aqueous dispersions, while a single layer of PP2b and PP3a was found on SWCNTs in organic dispersions. The dispersions were probed by steady-state and time-resolved spectroscopies, revealing appreciable charge redistribution in the ground state, and an efficient electron transfer from SWCNTs to PDIs in the excited state. We also fabricated hybrid materials from the PP2b/SWCNT dispersions. A supramolecular membrane was prepared from aqueous dispersions and used for size-selective separation of gold nanoparticles. Hybrid buckypaper films were prepared from the organic dispersions. In the latter, high conductivity results from enhanced electronic communication and favorable morphology within the hybrid material. Our findings shed light onto SWCNT/dispersant molecular interactions, and introduce a versatile approach toward universal solution processing of SWCNT-based materials.

  4. DLP-based 3D metrology by structured light or projected fringe technology for life sciences and industrial metrology

    NASA Astrophysics Data System (ADS)

    Frankowski, G.; Hainich, R.

    2009-02-01

    Since the mid-eighties, a fundamental idea for achieving measuring accuracy in projected fringe technology was to consider the projected fringe pattern as an interferogram and evaluate it on the basis of advanced algorithms widely used for phase measuring in real-time interferometry. A fundamental requirement for obtaining a sufficiently high degree of measuring accuracy with this so-called "phase measuring projected fringe technology" is that the projected fringes, analogous to interference fringes, must have a cos2-shaped intensity distribution. Until the mid-nineties, this requirement for the projected fringe pattern measurement technology presented a basic handicap for its wide application in 3D metrology. This situation changed abruptly, when in the nineties Texas Instruments introduced to the market advanced digital light projection on the basis of micro mirror based projection systems, socalled DLP technology, which also facilitated the generation and projection of cos2-shaped intensity and/or fringe patterns. With this DLP technology, which from its original approach was actually oriented towards completely different applications such as multimedia projection, Texas Instruments boosted phase-measuring fringe projection in optical 3D metrology to a worldwide breakthrough both for medical as well as industrial applications. A subject matter of the lecture will be to present the fundamental principles and the resulting advantages of optical 3D metrology based on phase-measuring fringe projection using DLP technology. Further will be presented and discussed applications of the measurement technology in medical engineering and industrial metrology.

  5. Application of an advanced atmospheric mesoscale model to dispersion in the Rocky Flats, Colorado vicinity

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.

    1993-01-01

    Atmospheric Studies in Complex Terrain (ASCOT) program sponsored a field experiment in the winter of 1991 near Rocky Flats, Colorado. Both meteorological and tracer dispersion measurements were taken. These two data sets provided an opportunity to investigate the influence of terrain-generated, radiatively-driven flows on the dispersion of the tracer. We use the Regional Atmospheric Modeling System (RAMS), originally developed at Colorado State University, to simulate meteorological conditions and tracer dispersion on the case night of 4-5 February 1991. The simulations described herein reveal considerable information about the extent to which the Rocky Mountains influence the flow along the Front Range , the importance of diffusion when simulating drainage flows and the computing needs of simulations in complex terrain regions.

  6. Application of an advanced atmospheric mesoscale model to dispersion in the Rocky Flats, Colorado vicinity

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.

    1993-02-01

    Atmospheric Studies in Complex Terrain (ASCOT) program sponsored a field experiment in the winter of 1991 near Rocky Flats, Colorado. Both meteorological and tracer dispersion measurements were taken. These two data sets provided an opportunity to investigate the influence of terrain-generated, radiatively-driven flows on the dispersion of the tracer. We use the Regional Atmospheric Modeling System (RAMS), originally developed at Colorado State University, to simulate meteorological conditions and tracer dispersion on the case night of 4-5 February 1991. The simulations described herein reveal considerable information about the extent to which the Rocky Mountains influence the flow along the Front Range , the importance of diffusion when simulating drainage flows and the computing needs of simulations in complex terrain regions.

  7. Fringe formation in dual-hologram interferometry

    NASA Astrophysics Data System (ADS)

    Burner, A. W.

    Reference-fringe formation in nondiffuse dual-hologram interferometry is described by combining a first-order geometrical hologram treatment with interference fringes generated by two point sources. The first-order imaging relationships can be used to describe reference-fringe patterns for the geometry of the dual-hologram interferometry. The process can be completed without adjusting the two holograms when the reconstructing wavelength is less than the exposing wavelength, and the process is found to facilitate basic intereferometer adjustments.

  8. Manufacture and engine test of advanced oxide dispersion strengthened alloy turbine vanes. [for space shuttle thermal protection

    NASA Technical Reports Server (NTRS)

    Bailey, P. G.

    1977-01-01

    Oxide-Dispersion-strengthened (ODS) Ni-Cr-Al alloy systems were exploited for turbine engine vanes which would be used for the space shuttle thermal protection system. Available commercial and developmental advanced ODS alloys were evaluated, and three were selected based on established vane property goals and manufacturing criteria. The selected alloys were evaluated in an engine test. Candidate alloys were screened by strength, thermal fatigue resistance, oxidation and sulfidation resistance. The Ni-16Cr (3 to 5)Al-ThO2 system was identified as having attractive high temperature oxidation resistance. Subsequent work also indicated exceptional sulfidation resistance for these alloys.

  9. Recent advance in ARPES data analysis of dispersive features in Fe-based superconductors

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Richard, Pierre; Qian, Tian; Dai, Xi; Ding, Hong; Xu, Yiming

    2012-02-01

    Angle-resolved photoemission spectroscopy (ARPES) is a powerful tool to image the electronic band dispersion of materials, especially in multi-band systems such as the Fe-based superconductors. Here we present a new method to visualize ARPES data based on the mathematical concept of curvature, which improves the advantages and the reliability of the second derivative method in tracking the positions of extrema from the experimental data. We apply it to the Fe-based superconductors. We reveal clear kink features and FS contours, making it easier to capture the essential physics from the data. [4pt] [1] P. Zhang, P. Richard, T. Qian, Y.-M. Xu, X. Dai and H. Ding, A precise method for visualizing dispersive features in image plots, Rev. Sci. Instrum. 82, 043712 (2011).

  10. Interference fringes in multiple Bragg-Laue mode and mirage fringes from bent crystals.

    PubMed

    Fukamachi, Tomoe; Tohyama, Masahiko; Hirano, Kenji; Yoshizawa, Masami; Negishi, Riichirou; Ju, Dongying; Hirano, Keiichi; Kawamura, Takaaki

    2010-05-01

    Interference fringes are measured in the diffraction from the surface as well as from the lateral surface of an Si single-crystal strip which is deformed in cantilever bending as a function of the tip displacement. The interference fringes are observed only when the bending strain is applied. Both interference fringes change conspicuously by increasing the bending strain. The number of the interference fringes changes, and the positions and heights of the peaks in the fringes change. These variations can be explained by the change of the interference between the beams in multiple Bragg-Laue modes and those of mirage diffraction based on the dynamical theory of diffraction.

  11. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... OF SEX § 1604.9 Fringe benefits. (a) “Fringe benefits,” as used herein, includes medical, hospital... prohibitions against sex discrimination contained in the act. (d) It shall be an unlawful employment practice... title VIII to a charge of sex discrimination in benefits that the cost of such benefits is greater...

  12. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits... Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION..., leave, and any other benefit or service of employment not subject to the provision of § 146.515....

  13. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits... Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION..., leave, and any other benefit or service of employment not subject to the provision of § 229.515....

  14. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe..., leave, and any other benefit or service of employment not subject to the provision of § 5.515....

  15. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe..., leave, and any other benefit or service of employment not subject to the provision of § 54.515....

  16. 29 CFR 1620.11 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION THE EQUAL PAY ACT § 1620.11 Fringe... unlawful for an employer to discriminate between men and women performing equal work with regard to fringe... spouses or families of employees of one gender where the same benefits are not made available for...

  17. American Involvement in Fringe Religious Cults

    ERIC Educational Resources Information Center

    Intellect, 1977

    1977-01-01

    "Twenty million Americans are involved in fringe religious cults such as spiritualism, Hare Krishna, Scientology, and Black Gospel groups," according to anthropologist Irving Zaretsky of the University of Chicago. He recently completed a 10-year period as a participant-observer of fringe religious groups in the San Francisco Bay area and the…

  18. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... OF SEX § 1604.9 Fringe benefits. (a) “Fringe benefits,” as used herein, includes medical, hospital... prohibitions against sex discrimination contained in the act. (d) It shall be an unlawful employment practice... title VIII to a charge of sex discrimination in benefits that the cost of such benefits is greater...

  19. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe...

  20. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe...

  1. Using advanced dispersion models and mobile monitoring to characterize spatial patterns of ultrafine particles in an urban area

    NASA Astrophysics Data System (ADS)

    Zwack, Leonard M.; Hanna, Steven R.; Spengler, John D.; Levy, Jonathan I.

    2011-09-01

    data and the advanced dispersion model QUIC provide insight about source contributions above background levels and spatiotemporal air pollution patterns in urban areas.

  2. Automatic analysis of speckle photography fringes.

    PubMed

    Buendía, M; Cibrián, R; Salvador, R; Roldán, C; Iñesta, J M

    1997-04-10

    Speckle interferometry is a technique adequate to metrological problems such as the measurement of object deformation. An automatic system of analysis of such measurements is given; it consists of a motorized x-y plate positioner controlled by computer, a CCD video camera, and software for image analysis. A fringe-recognition algorithm determines the spacing and orientation of the fringes and permits the calculation of the magnitude and direction of the displacement of the analyzed object point in images with variable degrees of illumination. For a 256 x 256 pixel image resolution, the procedure allows one to analyze from three fringes to a number of fringes that corresponds to 3 pixels/fringe.

  3. New advances in non-dispersive IR technology for CO2 detection

    NASA Technical Reports Server (NTRS)

    Small, John W.; Odegard, Wayne L.

    1988-01-01

    This paper discusses new technology developments in CO2 detection using Non-Dispersive Infrared (NDIR) techniques. The method described has successfully been used in various applications and environments. It has exhibited extremely reliable long-term stability without the need of routine calibration. The analysis employs a dual wavelength, differential detection approach with compensating circuitry for component aging and dirt accumulation on optical surfaces. The instrument fails 'safe' and provides the operator with a 'fault' alarm in the event of a system failure. The NDIR analyzer described has been adapted to NASA Space Station requirements.

  4. Interference fringe-patterns association to defect-types in artwork conservation: an experiment and research validation review

    NASA Astrophysics Data System (ADS)

    Tornari, Vivi; Tsiranidou, Elsa; Bernikola, Eirini

    2012-02-01

    The paper is directed to all classes of optical inspection technologies that are causing a fringe pattern like output, such as interferometry, fringe projection, holography, speckle techniques. The explanations given here are also valid for incoherent fringe projection, moire, and short-coherent techniques, which are producing fringe-like output correlated with the surface structure and the surface change, respectively. Identification of interference fringe patterns with defect type is a long-standing engineering problem with the ambiguities in cause-effect relation dominating the Cultural Heritage structural diagnosis. The ambiguities refer to fringe-pattern formation in regard to a hidden defect cause in the subsurface and the effect on the surface of the size or depth of the defect. In order to solve the concerned ambiguities, a review is made here to be confirmed a correlation of fringe pattern appearance to defect cause. The methodology is employed in the paper to achieve a generalized description of fringe morphology for a common type of inner defect as interlayer de-cohesion termed in art conservation as detachment and crack. The objective is to provide the required concept and procedure through which the validation of any defect-indicative fringe-pattern can serve as a direct-visual-control of structural condition in artwork examination. In this context, theoretical and experimental results starting from simulation algorithms, through knowledge based experiments and experimental verification to correlation procedures and mathematical analysis are combined to allow fringe pattern generalized validation. The result allows performing by means of modern optical metrology direct artwork documentation of structural diagnosis in complex art conservation problems. It helps to utilize it in other research objectives targeting in automated defect-recognition and multisensory technology. It helps to advance theoretical and practical routines in everyday practices of

  5. High-resolution, real-time fringe pattern profilometry

    NASA Astrophysics Data System (ADS)

    Karpinsky, Nikolaus; Lei, Shuangyan; Zhang, Song

    2009-12-01

    This paper presents some of our recent work on high-resolution, real-time 3D profilometry using a digital fringe projection method. In particular, we utilize the unique projection mechanism of a single-chip digital-light-processing (DLP) projector: sequential channel-by-channel switching. Three phase-shifted fringe patterns are encoded into the three primary color channels and switched naturally. A high-speed charge-coupled device (CCD) camera, synchronized with the projector, is used to capture each individual color channel of the projector. Because color is not desirable, the color filters of the projector are removed, and an external trigger signal is supplied to enable its projection. Since three fringe images are sufficient to reconstruction one shape, this technique can, theoretically, reach the refresh rate of a projector (typically 120 Hz). However, due to the speed limit of the camera used, the data acquisition speed is up to 180 fps, thus the 3D shape measurement speed can be as high as 60 fps, as it requires three images to recover one 3D shape. To reach simultaneous 3D data acquisition, reconstruction, and display, we developed various efficient algorithms, and used advanced graphics hardware techniques to boost the processing. In this paper, we will summarize the technologies we developed, and will present some of the research results.

  6. High-resolution, real-time fringe pattern profilometry

    NASA Astrophysics Data System (ADS)

    Karpinsky, Nikolaus; Lei, Shuangyan; Zhang, Song

    2010-03-01

    This paper presents some of our recent work on high-resolution, real-time 3D profilometry using a digital fringe projection method. In particular, we utilize the unique projection mechanism of a single-chip digital-light-processing (DLP) projector: sequential channel-by-channel switching. Three phase-shifted fringe patterns are encoded into the three primary color channels and switched naturally. A high-speed charge-coupled device (CCD) camera, synchronized with the projector, is used to capture each individual color channel of the projector. Because color is not desirable, the color filters of the projector are removed, and an external trigger signal is supplied to enable its projection. Since three fringe images are sufficient to reconstruction one shape, this technique can, theoretically, reach the refresh rate of a projector (typically 120 Hz). However, due to the speed limit of the camera used, the data acquisition speed is up to 180 fps, thus the 3D shape measurement speed can be as high as 60 fps, as it requires three images to recover one 3D shape. To reach simultaneous 3D data acquisition, reconstruction, and display, we developed various efficient algorithms, and used advanced graphics hardware techniques to boost the processing. In this paper, we will summarize the technologies we developed, and will present some of the research results.

  7. Hot melt extruded amorphous solid dispersion of posaconazole with improved bioavailability: investigating drug-polymer miscibility with advanced characterisation.

    PubMed

    Fule, Ritesh; Amin, Purnima

    2014-01-01

    Invasive antifungal infections are reasons for morbidity and mortality in immunogenic patients worldwide. Posaconazole is a most promising antifungal agent against all types of invasive infections with high % of cure rate. The marketed suspension formulation has low bioavailability and is needed to be taken with food. In this paper, PCZ hot melt extruded amorphous solid dispersion (SD) with immediate release and improved bioavailability was prepared using Soluplus (Sol) as primary carrier for solubilization. Surfactants such as PEG 400, Lutrol F27, Lutrol F68, and TPGS are also used in combination with Soluplus to improve the physicochemical performance of the formulation when it comes in contact with GI (gastrointestinal) fluid. Drug-polymer miscibility of SD was investigated using advanced techniques. In the in vivo study, the AUC(0-72) and C(max) of PCZ/Soluplus were 11.5 and 11.74 time higher than those of pure PCZ. The formulation of the extrudate SD had an AUC(0-72) and C(max) higher than those with the commercial capsule (Noxafil). Molecular dynamic (MD) simulation studies were carried out using in silico molecular modelling to understand the drug-polymer intermolecular behaviour. The results of this research ensure enhanced dissolution and bioavailability of the solid dispersion of PCZ prepared by HME compared with the PCZ suspension.

  8. Hot Melt Extruded Amorphous Solid Dispersion of Posaconazole with Improved Bioavailability: Investigating Drug-Polymer Miscibility with Advanced Characterisation

    PubMed Central

    Amin, Purnima

    2014-01-01

    Invasive antifungal infections are reasons for morbidity and mortality in immunogenic patients worldwide. Posaconazole is a most promising antifungal agent against all types of invasive infections with high % of cure rate. The marketed suspension formulation has low bioavailability and is needed to be taken with food. In this paper, PCZ hot melt extruded amorphous solid dispersion (SD) with immediate release and improved bioavailability was prepared using Soluplus (Sol) as primary carrier for solubilization. Surfactants such as PEG 400, Lutrol F27, Lutrol F68, and TPGS are also used in combination with Soluplus to improve the physicochemical performance of the formulation when it comes in contact with GI (gastrointestinal) fluid. Drug-polymer miscibility of SD was investigated using advanced techniques. In the in vivo study, the AUC(0–72) and Cmax of PCZ/Soluplus were 11.5 and 11.74 time higher than those of pure PCZ. The formulation of the extrudate SD had an AUC(0–72) and Cmax higher than those with the commercial capsule (Noxafil). Molecular dynamic (MD) simulation studies were carried out using in silico molecular modelling to understand the drug-polymer intermolecular behaviour. The results of this research ensure enhanced dissolution and bioavailability of the solid dispersion of PCZ prepared by HME compared with the PCZ suspension. PMID:25143935

  9. Phase demodulation from a spatial carrier fringe pattern by spatial-temporal fringes method

    NASA Astrophysics Data System (ADS)

    Lan, Bin; Feng, Guoying; Zhang, Tao; Zhou, Shouhuan

    2016-12-01

    Phase extraction from a single fringe pattern is a valuable but challenging task. In this paper, a spatial carrier phase-shifting algorithm based on spatial-temporal fringes method is proposed to demodulate the phase from a single carrier interfergram. Firstly, two phase-shifted fringe patterns are composed from the original interferogram shifting by several pixels their starting position. Secondly, these two phase shift fringes are fused into one spatial-temporal fringes (STF) image. Then, the modulating phase is calculated from the frequency spectrum of the STF image. Meanwhile, the main factors, such as the level of random noise, the carrier frequency values and angle of fringe pattern are analyzed and discussed in the simulations, and experimental results are given to demonstrate the validity of the proposed method. The proposed method is effective, accurate and immune to external disturbance and vibration, which greatly promotes the application in the on-line detection fields.

  10. Simplified fringe order correction for absolute phase maps recovered with multiple-spatial-frequency fringe projections

    NASA Astrophysics Data System (ADS)

    Ding, Yi; Peng, Kai; Lu, Lei; Zhong, Kai; Zhu, Ziqi

    2017-02-01

    Various kinds of fringe order errors may occur in the absolute phase maps recovered with multi-spatial-frequency fringe projections. In existing methods, multiple successive pixels corrupted by fringe order errors are detected and corrected pixel-by-pixel with repeating searches, which is inefficient for applications. To improve the efficiency of multiple successive fringe order corrections, in this paper we propose a method to simplify the error detection and correction by the stepwise increasing property of fringe order. In the proposed method, the numbers of pixels in each step are estimated to find the possible true fringe order values, repeating the search in detecting multiple successive errors can be avoided for efficient error correction. The effectiveness of our proposed method is validated by experimental results.

  11. 29 CFR 4.170 - Furnishing fringe benefits or equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... required under the determination in order to satisfy his fringe benefit obligations under the Act, and must... fringe benefit obligations which may be required by an applicable fringe benefit determination, such as... 29 Labor 1 2010-07-01 2010-07-01 true Furnishing fringe benefits or equivalents. 4.170 Section...

  12. Advanced coupled-micro-resonator architectures for dispersion and spectral engineering applications

    NASA Astrophysics Data System (ADS)

    Van, Vien

    2009-02-01

    We report recent progress in the design and fabrication of coupled optical micro-resonators and their applications in realizing compact OEIC devices for optical spectral engineering. By leveraging synthesis techniques for analog and digital electrical circuits, advanced coupled-microring device architectures can be realized with the complexity and functionality approaching that of state-of-the-art microwave filters. In addition, the traveling wave nature of microring resonators can be exploited to realize novel devices not possible with standing wave resonators. Applications of coupledmicro- resonator devices in realizing complex optical transfer functions for amplitude, phase and group delay engineering will be presented. Progress in the practical implementation of these devices in the Silicon-on-Insulator OEIC platform will be highlighted along with the challenges and potential for constructing very high order optical filters using coupledmicroring architectures.

  13. Precise parallel optical spectrum analysis using the advanced two-phonon light scattering combined with the cross-disperser technique.

    PubMed

    Shcherbakov, A S; Arellanes, A O; Chavushyan, V

    2016-12-01

    We develop an advanced approach to the optical spectrometer with acousto-optical dynamic grating for the Guillermo Haro astrophysical observatory (Mexico). The progress consists of two principle novelties. First is the use of the acousto-optical nonlinearity of two-phonon light scattering in crystals with linear acoustic losses. This advanced regime of light scattering exhibits a recently revealed additional degree of freedom, which allows tuning of the frequency of elastic waves and admits the nonlinear apodization improving the dynamic range. The second novelty is the combination of the cross-disperser with acousto-optical processing. A similar pioneering step provides an opportunity to operate over all the visible range in a parallel regime with maximal achievable resolution. The observation window of the optical spectrometer in that observatory is ∼9  cm, so that the theoretical estimations of maximal performances for a low-loss LiNbO3 crystal for this optical aperture at λ=405  nm give spectral resolution of 0.0523 Å, resolving power of 77,400, and 57,500 spots. The illustrative proof-of-principle experiments with a 6 cm LiNbO3 crystal have been performed.

  14. 29 CFR 1620.11 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... benefits. (a) “Fringe benefits” includes, e.g., such terms as medical, hospital, accident, life insurance... studies cannot be justified as based on “any other factor other than sex.” (c) Where an...

  15. Dispersion corrections of the copper K edge measured by Fresnel diffraction.

    PubMed

    Lee, Wah-Keat; Cloetens, Peter; Schlenker, Michel

    2004-01-01

    Dispersion corrections to the atomic scattering factors for the copper K edge have been measured by a new technique, Fresnel diffraction. Fresnel diffraction fringes were measured at several sample-detector distances as a function of energy across the copper K-absorption edge. The dispersion corrections were obtained from optimizing a least-squares fit of Fresnel fringe simulations to the measured data.

  16. Atmospheric dispersion modeling for the worst-case detonation accident at the proposed Advanced Hydrotest Facility

    SciTech Connect

    Bowen, B.M., LLNL

    1996-10-01

    The Atmospheric Release Advisory Capability (ARAC) was requested to estimate credible worst-case dose, air concentration, and deposition of airborne hazardous materials that would result from a worst-case detonation accident at the proposed Advanced Hydrotest Facility (AHT) at the Nevada Test Site (NTS). Consequences were estimated at the closest onsite facility, the Device Assembly Facility (DOFF), and offsite location (intersection of Highway and U.S. 95). The materials considered in this analysis were weapon-grade plutonium, beryllium, and hydrogen fluoride which is a combustion product whose concentration is dependent upon the quantity of high explosives. The analysis compares the calculated results with action guidelines published by the Department of Defense in DoD 5100.52-M (Nuclear Weapon Accident Response Procedures). Results indicate that based on a one kg release of plutonium the whole body radiation dose could be as high as 3 Rem at the DOFF. This level approaches the 5 Rem level for which the Department of Defense requires respiratory protection, recommends sheltering and the consideration of evacuation. Deposition levels at the DOFF could approach 6 uCi/m{sup 2} for which the Department of Defense recommends access on a need-only basis and suggests that a possible controlled evacuation might be required. For a one kg release of plutonium, the dose at the nearest off-site location could reach 0.5. At this level, the Department of Defense suggests that sheltering be considered. For a one kg release of beryllium, the peak 5-minute concentration at the DOFF could be as as 20% of 6xlO{sup -3} mg/m{sup 2} which is the applicable by Response Planning Guideline (ERPG-1). At the nearest offsite location, the beryllium concentrations from a one kg release would be two orders of magnitude less than the same guideline. For the detonation of 100 kg of the explosive LX-17, the concentration of hydrogen fluoride at both the DOFF and the nearest offsite location

  17. Phase extraction from two phase-shifting fringe patterns using spatial-temporal fringes method.

    PubMed

    Zhu, Ronggang; Li, Bo; Zhu, Rihong; He, Yong; Li, Jianxin

    2016-04-04

    Phase extraction from phase-shifting fringe patterns with unknown phase shift values is a valuable but challenging task, especially when there are only two frames of fringes. In this paper, a phase demodulation method based on the spatial-temporal fringes (STF) method is proposed, where two phase shift fringes with linear carrier are fused into one STF image, and then the measured phase can be extracted from its frequency spectrum. The algorithm is deduced by extending the traditional STF theory with at least three frames of fringes to the two frames case. In the simulations, its performance is compared with the classical Fourier Transform method, and the different carrier and phase step conditions are analyzed where the accuracy can be ensured in most cases. The algorithm is also validated by the experiment, where the reliable result can be given even if the phase shift changes within a wide range.

  18. Fringes in FTIR spectroscopy revisited: understanding and modelling fringes in infrared spectroscopy of thin films.

    PubMed

    Konevskikh, Tatiana; Ponossov, Arkadi; Blümel, Reinhold; Lukacs, Rozalia; Kohler, Achim

    2015-06-21

    The appearance of fringes in the infrared spectroscopy of thin films seriously hinders the interpretation of chemical bands because fringes change the relative peak heights of chemical spectral bands. Thus, for the correct interpretation of chemical absorption bands, physical properties need to be separated from chemical characteristics. In the paper at hand we revisit the theory of the scattering of infrared radiation at thin absorbing films. Although, in general, scattering and absorption are connected by a complex refractive index, we show that for the scattering of infrared radiation at thin biological films, fringes and chemical absorbance can in good approximation be treated as additive. We further introduce a model-based pre-processing technique for separating fringes from chemical absorbance by extended multiplicative signal correction (EMSC). The technique is validated by simulated and experimental FTIR spectra. It is further shown that EMSC, as opposed to other suggested filtering methods for the removal of fringes, does not remove information related to chemical absorption.

  19. DARWIN Fringe Sensor (DWARF): breadboard development

    NASA Astrophysics Data System (ADS)

    Schmidt, E.; Cassaing, F.; Hofer, S.; Barillot, M.; Baron, F.; Mugnier, L.; Rousset, G.; Stuffler, T.

    2003-10-01

    The current DARWIN design is based on six telescopes located on free-flying spacecraft, interferometrically combined on a central hub with free space propagation. Perfect mechanical stability of the system configuration is impossible, i.e. displacements, thermal effects and vibrations etc. are degrading the system performance. The purpose of the fringe sensor is to measure all relevant perturbations and to provide the necessary information to achieve co-phasing of the free-flying telescopes. This implies the measurement of differential piston/tip/tilt between the telescopes and selected higher-order aberrations on each pupil. The fringe sensor is thus a core component and the most critical real-time sensor in the DARWIN system. The goal of the current study is to identify and validate a high-precision fringe detection and tracking sensor called DWARF (DARWIN Astronomical Fringe Sensor) by setting up, characterising and testing a respective sensor breadboard. This paper summarises the requirements and the technological trade-off and describes the conceptual breadboard design and testing scheme. Another paper of this conference 'DARWIN Fringe Sensor (DWARF) Concept Study' by F. Cassaing et al. describes the concept selection.

  20. PERSPECTIVE: Fire on the fringe

    NASA Astrophysics Data System (ADS)

    Pyne, Stephen J.

    2009-09-01

    upgraded by further research, could solve. The drivers behind sprawl were fundamentally irrational: they resided in such inchoate urgings as aesthetics, a desire to `live in nature', a longing for personal privacy and social isolation. Correction required the imposition of science-based reason onto the scene, which argued for research. What you propose as a solution depends on how you define the problem. Houses were burning and residents too often dying; this was clearly a threat to public safety, an incitement for political action, and an incentive for research. But what were the causes? Scholarly disciplines and national traditions defined it differently. Europeans thought the issue fundamentally social. The breakdown in the old landscape created a disorder of which free-burning fire was a manifestation. This was in keeping with a long heritage of European thinking that identified fire with unrest and that argued that fire control was primarily a matter of social control. People needed to reassert their presence on the land. Those countries with large public estates such as Australia and the US conceived the problem in a converse way. At issue was the unwise (and unwarranted) encroachment of people into the bush. An ideal response would be to banish people from the fringe regions. Fire is `natural' and belongs in wildlands: it is people who upset the order of things. While government has a duty to shield its citizens from harm, it should not allow such measures to destroy nature preserves or the capacity of fire to propagate through them. People have to learn to `live with' fire. In both cases the prevailing assumption is that science will identify solutions, which society will apply. Yet here we have a case of countries implicitly pointing their national sciences in different directions because of their distinctive histories. It would seem that history as a discipline might also have something to contribute to this discourse both in terms of tracking land use and of

  1. iFringe: a fringe analysis application for mobile smart devices

    NASA Astrophysics Data System (ADS)

    Chan, Jacob; Teo, Josias Y. S.; Qian, Kemao

    2015-03-01

    This paper introduces iFringe, a mobile application that attempts to incorporate the resource heavy fringe analysis algorithms into the smart mobile devices platform. This first step taken towards mobility in the optical processing field aims to become a catalyst for modernization of various aspects of the field as well as to diversify developments to other applications. Predominantly, the motivation of this work stems from the vastly indifferent human interactive method of mobile devices, which enable images displayed on its touch screen to be manipulated in ways that could enhance the fringe analysis experience. Furthermore, given its hardware compatibility to the conventional fringe projection system, these mobile devices could potentially serve as a much more compact replacement. However, one imperative weakness that mobile devices pose is its limited computing ability. Therefore, to examine the feasibility of incorporating the fringe analysis algorithms into a mobile platform, we have implemented two fundamental fringe analysis techniques, namely the Fourier transform fringe analysis method and the phase-shifting technique. Formulas and processing procedures such as discrete Fourier transform (DFT) and quality-guided phase unwrapping, were included in accordance to their original algorithms to test their performance and usability on a smart mobile device. Details of the implementation and the performance results will also be presented in this paper to demonstrate the practicality of these algorithms on the smart mobile device platform.

  2. fringe and Notch specify polar cell fate during Drosophila oogenesis.

    PubMed

    Grammont, M; Irvine, K D

    2001-06-01

    fringe encodes a glycosyltransferase that modulates the ability of the Notch receptor to be activated by its ligands. We describe studies of fringe function during early stages of Drosophila oogenesis. Animals mutant for hypomorphic alleles of fringe contain follicles with an incorrect number of germline cells, which are separated by abnormally long and disorganized stalks. Analysis of clones of somatic cells mutant for a null allele of fringe localizes the requirement for fringe in follicle formation to the polar cells, and demonstrates that fringe is required for polar cell fate. Clones of cells mutant for Notch also lack polar cells and the requirement for Notch in follicle formation appears to map to the polar cells. Ectopic expression of fringe or of an activated form of Notch can generate an extra polar cell. Our results indicate that fringe plays a key role in positioning Notch activation during early oogenesis, and establish a function for the polar cells in separating germline cysts into individual follicles.

  3. The Offerings of Fringe Figures and Migrants

    ERIC Educational Resources Information Center

    Engels-Schwarzpaul, A.-Chr.

    2015-01-01

    "The Western tradition", as passe-partout, includes fringe figures, émigrés and migrants. Rather than looking to resources at the core of the Western tradition to overcome its own blindnesses, I am more interested in its gaps and peripheries, where other thoughts and renegade knowledges take hold. It is in the contact zones with…

  4. 14 CFR 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe...

  5. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or...) Discriminate on the basis of sex with regard to making fringe benefits available to employees or make...

  6. 14 CFR 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe...

  7. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in... recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe benefits available...

  8. Subtropical Biotic Fringing Reefs as Ecological Laboratories.

    ERIC Educational Resources Information Center

    Hunt, Jeffrey W.

    1980-01-01

    Describes a 16-week course in marine biology involving a class-coordinated investigation of a subtropical biotic fringing reef of Hawaii. Describes in detail the development of preliminary hypotheses regarding general cause-effect relationships on the reef, and the exploration of specific areas, such as chemical or physical factors. (CS)

  9. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Fringe benefits. 1317.525 Section 1317.525 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL...

  10. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Fringe benefits. 1317.525 Section 1317.525 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL...

  11. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION... Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 618.525...

  12. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION... Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 618.525...

  13. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION... Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 618.525...

  14. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION... Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 618.525...

  15. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION...: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan,...

  16. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Fringe benefits. 5.525 Section 5.525 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of...

  17. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Fringe benefits. 5.525 Section 5.525 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of...

  18. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Fringe benefits. 5.525 Section 5.525 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of...

  19. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Regulations of the Offices of the Department of Education OFFICE FOR CIVIL RIGHTS, DEPARTMENT OF EDUCATION... participate in a fringe benefit plan which does not provide either for equal periodic benefits for members of each sex, or for equal contributions to the plan by such recipient for members of each sex; or...

  20. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Regulations of the Offices of the Department of Education OFFICE FOR CIVIL RIGHTS, DEPARTMENT OF EDUCATION... participate in a fringe benefit plan which does not provide either for equal periodic benefits for members of each sex, or for equal contributions to the plan by such recipient for members of each sex; or...

  1. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Regulations of the Offices of the Department of Education OFFICE FOR CIVIL RIGHTS, DEPARTMENT OF EDUCATION... participate in a fringe benefit plan which does not provide either for equal periodic benefits for members of each sex, or for equal contributions to the plan by such recipient for members of each sex; or...

  2. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or...) Discriminate on the basis of sex with regard to making fringe benefits available to employees or make...

  3. 49 CFR 25.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Transportation Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe...

  4. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in... recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe benefits available...

  5. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or...) Discriminate on the basis of sex with regard to making fringe benefits available to employees or make...

  6. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe...

  7. Speckle-adaptive VISAR fringe analysis technique

    NASA Astrophysics Data System (ADS)

    Erskine, David

    2017-01-01

    A line-VISAR (velocity interferometer) is an important diagnostic in shock physics, simultaneously measuring many fringe histories of adjacent portions of a target splayed along a line on a target, with fringes recorded vs time and space by a streak camera. Due to laser speckle the reflected intensity may be uneven spatially, and due to irregularities in the streak camera electron optics the phase along the slit may be slightly nonlinear. Conventional fringe analysis algorithms which do not properly model these variations can suffer from inferred velocity errors. A speckle-adaptive algorithm has been developed which senses the interferometer and illumination parameters for each individual row (spatial position Y) of the 2d interferogram, so that the interferogram can be compensated for Y-dependent nonfringing intensity, fringe visibility, and nonlinear phase distribution. In numerical simulations and on actual data we have found this individual row-by-row modeling improves the accuracy of the result, compared to a conventional column-by-column analysis approach.

  8. Benefits/fringes under better control

    SciTech Connect

    Mantho, M.

    1995-07-01

    Fringe benefits, e.g., health insurance for employees in the fuel oil industry are discussed. It was concluded that only 12% of the companies had cut benefits but that these benefits were costing less. This would seem to indicate that the cost of these benefits was being controlled better perhaps by more sharing of these costs.

  9. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a)...

  10. 26 CFR 1.132-8 - Fringe benefit nondiscrimination rules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... benefit program, i.e., either different fringe benefits being provided to the same group of employees, or... separately to each such program. Thus, a determination that one fringe benefit program discriminates in favor of highly compensated employees generally will not cause other fringe benefit programs covering...

  11. 26 CFR 1.132-8 - Fringe benefit nondiscrimination rules.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... benefit program, i.e., either different fringe benefits being provided to the same group of employees, or... separately to each such program. Thus, a determination that one fringe benefit program discriminates in favor of highly compensated employees generally will not cause other fringe benefit programs covering...

  12. Advances in colloid and biocolloid transport in porous media: particle size-dependent dispersivity and gravity effects

    NASA Astrophysics Data System (ADS)

    Chrysikopoulos, Constantinos V.; Manariotis, Ioannis D.; Syngouna, Vasiliki I.

    2014-05-01

    Accurate prediction of colloid and biocolloid transport in porous media relies heavily on usage of suitable dispersion coefficients. The widespread procedure for dispersion coefficient determination consists of conducting conservative tracer experiments and subsequently fitting the collected breakthrough data with a selected advection-dispersion transport model. The fitted dispersion coefficient is assumed to characterize the porous medium and is often used thereafter to analyze experimental results obtained from the same porous medium with other solutes, colloids, and biocolloids. The classical advection-dispersion equation implies that Fick's first law of diffusion adequately describes the dispersion process, or that the dispersive flux is proportional to the concentration gradient. Therefore, the above-described procedure inherently assumes that the dispersive flux of all solutes, colloids and biocolloids under the same flow field conditions is exactly the same. Furthermore, the available mathematical models for colloid and biocoloid transport in porous media do not adequately account for gravity effects. Here an extensive laboratory study was undertaken in order to assess whether the dispersivity, which traditionally has been considered to be a property of the porous medium, is dependent on colloid particle size, interstitial velocity and length scale. The breakthrough curves were successfully simulated with a mathematical model describing colloid and biocolloid transport in homogeneous, water saturated porous media. The results demonstrated that the dispersivity increases very slowly with increasing interstitial velocity, and increases with column length. Furthermore, contrary to earlier results, which were based either on just a few experimental observations or experimental conditions leading to low mass recoveries, dispersivity was positively correlated with colloid particle size. Also, transport experiments were performed with biocolloids (bacteriophages:

  13. Interference fringes detected by OEDIPUS C

    NASA Astrophysics Data System (ADS)

    James, H. G.; Calvert, W.

    1998-05-01

    An HF transmitter was operated at one end of the tethered sounding rocket payload OEDIPUS C, and a synchronized receiver was operated at the other end. Both the transmitter and the receiver were connected to dipoles. On the flight downleg after the tether had been cut, direct bistatic propagation experiments were carried out with the transmitter-receiver pair. During the flight, sharp minima which can be attributed to interference fringes were detected in the directly transmitted signal. Fringe frequencies observed on OEDIPUS C ionograms for four different interference schemes have been examined using the cold-plasma theory. First, fringes were observed which can be attributed to the Faraday rotation of the plane of linear electric field polarization for the combined O- and X-mode or O- and Z-mode waves. The electric field rotation was calculated using independent measurements of the plasma parameters and the attitudes of the transmitting and receiving dipoles. Another kind of fringe occurred for the whistler (W) and Z-mode waves as a result of their triple-valued refractive index below half the cyclotron frequency for the W mode and just below the plasma frequency for the Z mode. The hypothesis has been tested that these "single-mode" fringes are caused by the cancellation of the wave field of two circularly polarized Z-mode or W-mode waves excited by the linearly polarized transmitting antenna, at the point where the two waves' electric fields are shifted in phase by 180°. The theory for the single-mode nulls correctly predicts the frequency range and the spacing of the fringes but fails to explain absolute frequencies in all cases. This failure points to the need for a complete computation of the dipole radiated field which is expected to have considerable structure on account of the inflection points on the W- and Z-mode refractive index surfaces. The OEDIPUS C bistatic propagation experiment has demonstrated Faraday rotation in situ. The agreement between

  14. A role for analytical chemistry in advancing our understanding of the occurrence, fate, and effects of Corexit Oil Dispersants

    USGS Publications Warehouse

    Place, Ben; Anderson, Brian; Mekebri, Abdou; Furlong, Edward T.; Gray, James L.; Tjeerdema, Ron; Field, Jennifer

    2010-01-01

    On April 24, 2010, the sinking of the Deepwater Horizon oil rig resulted in the release of oil into the Gulf of Mexico. As of July 19, 2010, the federal government's Deepwater Horizon Incident Joint Information Center estimates the cumulative range of oil released is 3,067,000 to 5,258,000 barrels, with a relief well to be completed in early August. By comparison, the Exxon Valdez oil spill released a total of 260,000 barrels of crude oil into the environment. As of June 9, BP has used over 1 million gallons of Corexit oil dispersants to solubilize oil and help prevent the development of a surface oil slick. Oil dispersants are mixtures containing solvents and surfactants that can exhibit toxicity toward aquatic life and may enhance the toxicity of components of weathered crude oil. Detailed knowledge of the composition of both Corexit formulations and other dispersants applied in the Gulf will facilitate comprehensive monitoring programs for determining the occurrence, fate, and biological effects of the dispersant chemicals. The lack of information on the potential impacts of oil dispersants has caught industry, federal, and state officials off guard. Until compositions of Corexit 9500 and 9527 were released by the U.S. Environmental Protection Agency online, the only information available consisted of Material Safety Data Sheets (MSDS), patent documentation, and a National Research Council report on oil dispersants. Several trade and common names are used for the components of the Corexits. For example, Tween 80 and Tween 85 are oligomeric mixtures.

  15. Phase Analysis of Fringe Pattern In Shearography

    NASA Astrophysics Data System (ADS)

    Yusof, M. Y.; Abdullah, W. S. Wan

    2008-05-01

    This paper discusses the phase analysis of interference pattern from coherent light Nd:YAG 532 nm laser source. The Twyman-Green Interferometer set-up is used for generating the fringe pattern in the phase calibration. The piezoelectric transducer (PZT) is used to achieve the required phase shift of the fringe pattern. It was found that the system required 8.8 volts of out-put DC voltage to shift 2π radians phase. The accuracy of optical phase measurement of the interference pattern is analyzed by wrapped phases of three-phase stepping and four-phase stepping procedures. Comparison of the experimental phase measurement data and the theoretical phase calculations are also highlighted.

  16. Physicochemical characterization and aerosol dispersion performance of organic solution advanced spray-dried cyclosporine A multifunctional particles for dry powder inhalation aerosol delivery.

    PubMed

    Wu, Xiao; Zhang, Weifen; Hayes, Don; Mansour, Heidi M

    2013-01-01

    In this systematic and comprehensive study, inhalation powders of the polypeptide immunosuppressant drug - cyclosporine A - for lung delivery as dry powder inhalers (DPIs) were successfully designed, developed, and optimized. Several spray drying pump rates were rationally chosen. Comprehensive physicochemical characterization and imaging was carried out using scanning electron microscopy, hot-stage microscopy, differential scanning calorimetry, powder X-ray diffraction, Karl Fischer titration, laser size diffraction, and gravimetric vapor sorption. Aerosol dispersion performance was conducted using a next generation impactor with a Food and Drug Administration-approved DPI device. These DPIs displayed excellent aerosol dispersion performance with high values in emitted dose, respirable fraction, and fine particle fraction. In addition, novel multifunctional inhalation aerosol powder formulations of cyclosporine A with lung surfactant-mimic phospholipids were also successfully designed and developed by advanced organic solution cospray drying in closed mode. The lung surfactantmimic phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-snglycero- 3-(phosphor-rac-1-glycerol). These cyclosporine A lung surfactant-mimic aerosol powder formulations were comprehensively characterized. Powder X-ray diffraction and differential scanning calorimetry confirmed that the phospholipid bilayer structure in the solid state was preserved following advanced organic solution spray drying in closed mode. These novel multifunctional inhalation powders were optimized for DPI delivery with excellent aerosol dispersion performance and high aerosol performance parameters.

  17. Physicochemical characterization and aerosol dispersion performance of organic solution advanced spray-dried cyclosporine A multifunctional particles for dry powder inhalation aerosol delivery

    PubMed Central

    Wu, Xiao; Zhang, Weifen; Hayes, Don; Mansour, Heidi M

    2013-01-01

    In this systematic and comprehensive study, inhalation powders of the polypeptide immunosuppressant drug – cyclosporine A – for lung delivery as dry powder inhalers (DPIs) were successfully designed, developed, and optimized. Several spray drying pump rates were rationally chosen. Comprehensive physicochemical characterization and imaging was carried out using scanning electron microscopy, hot-stage microscopy, differential scanning calorimetry, powder X-ray diffraction, Karl Fischer titration, laser size diffraction, and gravimetric vapor sorption. Aerosol dispersion performance was conducted using a next generation impactor with a Food and Drug Administration-approved DPI device. These DPIs displayed excellent aerosol dispersion performance with high values in emitted dose, respirable fraction, and fine particle fraction. In addition, novel multifunctional inhalation aerosol powder formulations of cyclosporine A with lung surfactant-mimic phospholipids were also successfully designed and developed by advanced organic solution cospray drying in closed mode. The lung surfactantmimic phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-snglycero- 3-(phosphor-rac-1-glycerol). These cyclosporine A lung surfactant-mimic aerosol powder formulations were comprehensively characterized. Powder X-ray diffraction and differential scanning calorimetry confirmed that the phospholipid bilayer structure in the solid state was preserved following advanced organic solution spray drying in closed mode. These novel multifunctional inhalation powders were optimized for DPI delivery with excellent aerosol dispersion performance and high aerosol performance parameters. PMID:23569375

  18. Morphology of leaves cuticle by fringe projection

    NASA Astrophysics Data System (ADS)

    Martínez, Amalia; Rayas Alvarez, J. A.; Cordero, Raúl; Balieiro R., Daniela

    2011-10-01

    The development of this work is important in the morphological study of plant parts, specifically in the study of the cuticle of fruits or leaves. The implemented optical technique for fringe projection can identify potential fracture zones which damage the presentation of the fruits impacting business as well as producing them. Specifically, we obtained information on the thickness of a cuticle corresponding to the abaxial surface of a leaf of apple (Malus domestica) of the variety Golden Delicious.

  19. The Effect of Lateralized Temporal Fringes on Fundamental Frequency Discrimination

    NASA Astrophysics Data System (ADS)

    Gockel, H.; Carlyon, R. P.; Micheyl, C.

    Fundamental frequency (FO) discrimination can be impaired substantially by the presence of another complex (the "fringe") immediately before and after the target complex. It has been shown [2] that for the impairment to occur (i) target and fringes have to be in the same frequency region; (ii) if all harmonics of target and fringes are unresolved then they may differ in F0; otherwise, they have to be similar. The present experiments investigated the effect of fringes lateralized differently from the target. In a 21-2AFC procedure, difference limens for FO for a 100-ms harmonic target complex were measured in the presence and absence of 200-ms harmonic fringes. The nominal FO was 88 Hz or 250 Hz. Stimuli were bandpass filtered between 125-625 Hz, 1375-1875 Hz, or 3900-5400 Hz. The target was presented monaurally, while the fringes were: (i) contralateral with the same level as the target, (ii) contralateral with a level increased by 20 dB, (iii) dichotic (ILD of +20 dB contralateral), (iv) diotic, and (v) ipsilateral. The effect of the fringes was reduced when their subjective location differed from that of the target. This reduction depended on the resolvability of both the fringes and the target. The results are consistent with the idea that the fringes produce interference when the listeners have difficulty segregating the target from the fringes.

  20. Oxygen Transfer in a Fluctuating Capillary Fringe: Impact of Porous Medium Heterogeneity

    NASA Astrophysics Data System (ADS)

    Haberer, C.; Rolle, M.; Cirpka, O. A.; Grathwohl, P.

    2013-12-01

    Mass transfer of oxygen from the atmosphere, across the capillary fringe, to anoxic groundwater is of primary importance for many biogeochemical processes affecting groundwater quality. The controlling mechanisms for oxygen transfer across the capillary fringe are the diffusive/dispersive transport as well as mass exchange between entrapped air and groundwater. In addition, the presence of physical heterogeneity in the porous medium may strongly affect the oxygen fluxes. We performed quasi two-dimensional flow-through experiments at the laboratory bench-scale to study the effect of a coarse-material inclusion, located in proximity of the water table, on flow and oxygen transfer in the capillary fringe. Flow and transport were monitored under both steady-state and transient flow conditions, the latter obtained by fluctuating the water table. We visually inspected the complex flow field using a dye tracer solution, measured vertical oxygen profiles across the capillary fringe at high spatial resolution, and determined oxygen fluxes in the effluent of the flow-through chamber. Our results show that the coarse-material inclusion significantly affected oxygen transfer during the different phases of the experiments. At steady state, the oxygen flux across the unsaturated/saturated interface was considerably enhanced due to flow focusing in the fully water-saturated coarse lens. During drainage, the capillary barrier effect prevented water to drain from the fine material overlying the coarse lens. The entrapped oxygen-rich aqueous phase contributed to the total amount of oxygen supplied to the system when the water table was raised back to its initial level. In case of imbibition, also pronounced entrapment of air occurred in the coarse lens, causing oxygen to partition between the aqueous and gaseous phases. Thus, we found that oxygen transfer across the capillary fringe was significantly enhanced by the coarse-material inclusion due to flow focusing, the capillary

  1. Colloid Mobilization and Transport during Capillary Fringe Fluctuations

    NASA Astrophysics Data System (ADS)

    Aramrak, Surachet; Flury, Markus

    2016-04-01

    Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead filled column. Confocal images showed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively-charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively-charged colloids did not attach to static air-bubbles, but hydrophobic negatively-charged and hydrophilic positively-charged colloids did.

  2. IRSFRINGE: Interactive tool for fringe removal from Spitzer IRS spectra

    NASA Astrophysics Data System (ADS)

    IRS Team at Cornell University

    2016-02-01

    IRSFRINGE is an IDL-based GUI package that allows observers to interactively remove fringes from IRS spectra. Fringes that originate from the detector subtrates are observed in the IRS Short-High (SH) and Long-High (LH) modules. In the Long-Low (LL) module, another fringe component is seen as a result of the pre-launch change in one of the LL filters. The fringes in the Short-Low (SL) module are not spectrally resolved. the fringes are already largely removed in the pipeline processing when the flat field is applied. However, this correction is not perfect and remaining fringes can be removed with IRSFRINGE from data in each module. IRSFRINGE is available as a stand-alone package and is also part of the Spectroscopic Modeling, Analysis and Reduction Tool (SMART, ascl:1210.021).

  3. LineVISAR. A fringe-trace data analysis program

    SciTech Connect

    Furnish, Michael D.

    2014-02-01

    The line-imaging ORVIS or VISAR provides velocity as a function of position and time for a line on an experimental setup via a streak camera record of interference fringes. This document describes a Matlab-based program which guides the user through the process of converting these fringe data to a velocity surface. The data reduction is of the "fringe trace" type, wherein the changes in velocity at a given position on the line are calculated based on fringe motion past that point. The analyst must establish the fringe behavior up front, aided by peak-finding routines in the program. However, the later work of using fringe jumps to compensate for phase problems in other analysis techniques is greatly reduced. This program is not a standard GUI construction, and is prescriptive. At various points it saves the progress, allowing later restarts from those points.

  4. Fringe stabilizers and their application to telecommunication device manufacturing

    NASA Astrophysics Data System (ADS)

    Odhner, Jefferson E.

    2000-10-01

    The ability to create stable holographic grating is an important part of the production of many telecommunication products. The stability problem is increased by the need to use ultra-violet light for close fringe spacing and long exposure times on phot-resist - a relatively low sensitivity material. Active fringe locking increases the modulation depth and efficiency of these holographic gratings. A discussion of how fringe lockers work and how they can be incorporated into a manufacturing set-up is followed by results of using fringe lockers in the manufacturing of some telecommunication devices.

  5. Advanced Numerical Modeling of the Dispersion of Ceramic Nanoparticles during Ultrasonic Cavitation Processing and Solidification of 6061-based Nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhang, D.; Nastac, L.

    2015-06-01

    The metal-matrix-nano-composites (MMNCs) in this study consist of a 6061 alloy matrix reinforced with 1.0 wt.% SiC 50 nm diameter nanoparticles that are dispersed uniformly within the matrix in large volume using an ultrasonic cavitation dispersion technique (UCDS) available in the Solidification Laboratory at UA. The required ultrasonic parameters to achieve the required cavitation for adequate degassing and refining of the aluminium alloy as well as the fluid flow characteristics for uniform dispersion of the nanoparticles into the 6061 matrix are being investigated in this study by using an in-house developed CFD ultrasonic cavitation model. The multiphase CFD model accounts for turbulent fluid flow, heat transfer and solidification as well as the complex interaction between the solidifying alloy and nanoparticles by using the Ansys's Fluent Dense Discrete Phase Model (DDPM) and a particle engulfment and pushing (PEP) model. The PEP model accounts for the Brownian motion. SEM analysis was performed on the as-cast MMNC coupons processed via UCDS and confirmed the distribution of the nanoparticles predicted by the current CFD model. A parametric study was performed using the validated CFD model. The study includes the effects of magnitude of the fluid flow and ultrasonic probe location (gravity direction).

  6. Aspheric mirror measurement based on fringe reflection

    NASA Astrophysics Data System (ADS)

    Su, Xianyu; Tang, Yan; Liu, Yuankun; Zhang, Qican; Xiang, Liqun

    2009-05-01

    The aspheric mirror can correct aberrations and improve imaging quality of optical system . M oreover using such mirror can reduce the num ber of optical elem ents in an optical system and further reduce the weight and size of the system . In order to improve the accuracy of aspheric mirror fabrication, there are many methods used to m easure aspheric mirror. Am ong these methods, the most popular one is interferom etry which can m easure the surface with very high accuracy. However, interferom etry commonly requires com plicated and expensive assistant optics, and its m easurem ent range is limited. In order to measure aspheric mirror conveniently and effectively, we further evolve the well know n approaches of 'Phase M easuring Deflectom ety'(PM D) to measure such surface. In this study, we present a novel m ethod based on fringe reflection to m easure aspheric m irror. In the m easurem ent process, the screen and the cam era are m oved along the mirror optical axis, respectively. Using the phase information of the recording fringe patterns, for each cam era pixel, we can calculate the slope and coordinate of its corresponding point on the surface to be tested. By integrating, the absolute height of the tested surface can be reconstructed. Com pared with traditional PM D, this m ethod can m easure the absolute height of an aspheric m irror unam biguously and doesn't need com plex calibration.

  7. Adaptive DFT-Based Interferometer Fringe Tracking

    NASA Astrophysics Data System (ADS)

    Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

    An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

  8. SOFAST: Sandia Optical Fringe Analysis Slope Tool

    SciTech Connect

    Andraka, Charles E.

    2015-10-20

    SOFAST is used to characterize the surface slope of reflective mirrors for solar applications. SOFAST uses a large monitor or projections screen to display fringe patterns, and a machine vision camera to image the reflection of these patterns in the subject mirror. From these images, a detailed map of surface normals can be generated and compared to design or fitted mirror shapes. SOFAST uses standard Fringe Reflection (Deflectometry) approaches to measure the mirror surface normals. SOFAST uses an extrinsic analysis of key points on the facet to locate the camera and monitor relative to the facet coordinate system. It then refines this position based on the measured surface slope and integrated shape of the mirror facet. The facet is placed into a reference frame such that key points on the facet match the design facet in orientation and position. This is key to evaluating a facet as suitable for a specific solar application. SOFAST reports the measurements of the facet as detailed surface normal location in a format suitable for ray tracing optical analysis codes. SOFAST also reports summary information as to the facet fitted shape (monomial) and error parameters. Useful plots of the error distribution are also presented.

  9. An analysis of the phase dispersion in the symmetric beam combiner

    NASA Technical Reports Server (NTRS)

    Tang, Hong; Zhao, Feng

    2006-01-01

    An astronomical beam combiner combines the two beams of starlight to form white-light fringes. It is desirable that the dispersion of the beam combiner be minimized across the observation wavelength range. We present here an analysis of the phase dispersion from coatings for a symmetric beam combiner. The sensitivity of the dispersion to a slight mismatch in beamsplitter coatings is also studied.

  10. Combined dispersive/interference spectroscopy for producing a vector spectrum

    DOEpatents

    Erskine, David J.

    2002-01-01

    A method of measuring the spectral properties of broadband waves that combines interferometry with a wavelength disperser having many spectral channels to produce a fringing spectrum. Spectral mapping, Doppler shifts, metrology of angles, distances and secondary effects such as temperature, pressure, and acceleration which change an interferometer cavity length can be measured accurately by a compact instrument using broadband illumination. Broadband illumination avoids the fringe skip ambiguities of monochromatic waves. The interferometer provides arbitrarily high spectral resolution, simple instrument response, compactness, low cost, high field of view and high efficiency. The inclusion of a disperser increases fringe visibility and signal to noise ratio over an interferometer used alone for broadband waves. The fringing spectrum is represented as a wavelength dependent 2-d vector, which describes the fringe amplitude and phase. Vector mathematics such as generalized dot products rapidly computes average broadband phase shifts to high accuracy. A Moire effect between the interferometer's sinusoidal transmission and the illumination heterodynes high resolution spectral detail to low spectral detail, allowing the use of a low resolution disperser. Multiple parallel interferometer cavities of fixed delay allow the instantaneous mapping of a spectrum, with an instrument more compact for the same spectral resolution than a conventional dispersive spectrometer, and not requiring a scanning delay.

  11. High-accuracy thickness measurement of a transparent plate with the heterodyne central fringe identification technique

    SciTech Connect

    Wu, Wang-Tsung; Hsieh, Hung-Chih; Chang, Wei-Yao; Chen, Yen-Liang; Su, Der-Chin

    2011-07-20

    In a modified Twyman-Green interferometer, the optical path variation is measured with the heterodyne central fringe identification technique, as the light beam is focused by a displaced microscopic objective on the front/rear surface of the test transparent plate. The optical path length variation is then measured similarly after the test plate is removed. The geometrical thickness of the test plate can be calculated under the consideration of dispersion effect. This method has a wide measurable range and a high accuracy in the measurable range.

  12. High-accuracy thickness measurement of a transparent plate with the heterodyne central fringe identification technique.

    PubMed

    Wu, Wang-Tsung; Hsieh, Hung-Chih; Chang, Wei-Yao; Chen, Yen-Liang; Su, Der-Chin

    2011-07-20

    In a modified Twyman-Green interferometer, the optical path variation is measured with the heterodyne central fringe identification technique, as the light beam is focused by a displaced microscopic objective on the front/rear surface of the test transparent plate. The optical path length variation is then measured similarly after the test plate is removed. The geometrical thickness of the test plate can be calculated under the consideration of dispersion effect. This method has a wide measurable range and a high accuracy in the measurable range.

  13. High-accuracy thickness measurement of a transparent plate with the heterodyne central fringe identification technique

    NASA Astrophysics Data System (ADS)

    Wu, Wang-Tsung; Hsieh, Hung-Chih; Chang, Wei-Yao; Chen, Yen-Liang; Su, Der-Chin

    2011-07-01

    In a modified Twyman--Green interferometer, the optical path variation is measured with the heterodyne central fringe identification technique, as the light beam is focused by a displaced microscopic objective on the front/rear surface of the test transparent plate. The optical path length variation is then measured similarly after the test plate is removed. The geometrical thickness of the test plate can be calculated under the consideration of dispersion effect. This method has a wide measurable range and a high accuracy in the measurable range.

  14. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... compensation at a specified future date or a fixed amount of qualified transportation fringes to be provided for a specified future period (such as qualified parking to be used during a future calendar month... that is not used for qualified transportation fringes is not refunded to the employee at any...

  15. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... compensation at a specified future date or a fixed amount of qualified transportation fringes to be provided for a specified future period (such as qualified parking to be used during a future calendar month... that is not used for qualified transportation fringes is not refunded to the employee at any...

  16. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... compensation at a specified future date or a fixed amount of qualified transportation fringes to be provided for a specified future period (such as qualified parking to be used during a future calendar month... that is not used for qualified transportation fringes is not refunded to the employee at any...

  17. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... compensation at a specified future date or a fixed amount of qualified transportation fringes to be provided for a specified future period (such as qualified parking to be used during a future calendar month... that is not used for qualified transportation fringes is not refunded to the employee at any...

  18. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... compensation at a specified future date or a fixed amount of qualified transportation fringes to be provided for a specified future period (such as qualified parking to be used during a future calendar month... that is not used for qualified transportation fringes is not refunded to the employee at any...

  19. 29 CFR 4.52 - Fringe benefit determinations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefit determinations. 4.52 Section 4.52 Labor... Procedures § 4.52 Fringe benefit determinations. (a) Wage determinations issued pursuant to the Service... addition, wage determinations contain a prescribed minimum rate for all other benefits, such as...

  20. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... individual employee receives such a fringe benefit is not relevant and in some circumstances, the de minimis fringe exclusion may apply with respect to a benefit even though a particular employee receives the benefit frequently. For example, if an employer exercises sufficient control and imposes...

  1. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... individual employee receives such a fringe benefit is not relevant and in some circumstances, the de minimis fringe exclusion may apply with respect to a benefit even though a particular employee receives the benefit frequently. For example, if an employer exercises sufficient control and imposes...

  2. The Gender Pay Gap, Fringe Benefits, and Occupational Crowding.

    ERIC Educational Resources Information Center

    Solberg, Eric; Laughlin, Teresa

    1995-01-01

    In estimating earnings equations for seven occupations, when fringe benefits are excluded, women receive significantly lower wages in all but the most female-dominated occupation. Including fringe benefits makes gender significant in only one occupational category. Crowding of one gender into an occupation appears the primary determinant of the…

  3. The Effects of Fringe Fields on Organic Magnetoresistance

    NASA Astrophysics Data System (ADS)

    Harmon, Nicholas; Macià, Ferran; Wang, Fujian; Wohlgenannt, Markus; Kent, Andrew; Flatté, Michael

    2013-03-01

    The importance of random hyperfine fields is now widely acknowledged as a vital ingredient for the phenomena of organic magnetoresistance (OMAR). Recent experiments (Phys. Rev. X 2 021013 (2012)) have shown that another type of random field - fringe fields due to a nearby ferromagnet - can also dramatically affect magnetoconductivity. A theoretical analysis of the fringe field OMAR is challenging due to the different properties of the fringe fields when compared to the hyperfine fields. For instance, the range of fringe field strengths is 1-2 orders of magnitude larger than that of the hyperfine couplings. The correlation length between fringe fields is also larger by the same degree. We use a recent theory of OMAR that is well-suited to numerically calculate the magnetoresistance with both hyperfine and fringe fields present. We find agreement with key features of experimental fringe-field magnetoresistance dependences on applied magnetic field, including the field values of extrema of the magnetoresistance, the region of large magnetoresistance effects from the fringe fields, and the sign of the effect. This work was supported by an ARO MURI.

  4. [Fringe Benefits: The Not-So Invisible Cost.

    ERIC Educational Resources Information Center

    Allen, David

    The speaker notes the increasingly important role that fringe benefits are playing in the collective bargaining process and offers examples of the costs--both direct and indirect--of these benefits--both economic and "noneconomic"--from his district. The speaker's district put a lid on the costs of fringe benefits by setting a fixed…

  5. Advanced spray-dried design, physicochemical characterization, and aerosol dispersion performance of vancomycin and clarithromycin multifunctional controlled release particles for targeted respiratory delivery as dry powder inhalation aerosols.

    PubMed

    Park, Chun-Woong; Li, Xiaojian; Vogt, Frederick G; Hayes, Don; Zwischenberger, Joseph B; Park, Eun-Seok; Mansour, Heidi M

    2013-10-15

    Respirable microparticles/nanoparticles of the antibiotics vancomycin (VCM) and clarithromycin (CLM) were successfully designed and developed by novel organic solution advanced spray drying from methanol solution. Formulation optimization was achieved through statistical experimental design of pump feeding rates of 25% (Low P), 50% (Medium P) and 75% (High P). Systematic and comprehensive physicochemical characterization and imaging were carried out using scanning electron microscopy (SEM), hot-stage microscopy (HSM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Karl Fischer titration (KFT), laser size diffraction (LSD), gravimetric vapor sorption (GVS), confocal Raman microscopy (CRM) and spectroscopy for chemical imaging mapping. These novel spray-dried (SD) microparticulate/nanoparticulate dry powders displayed excellent aerosol dispersion performance as dry powder inhalers (DPIs) with high values in emitted dose (ED), respirable fraction (RF), and fine particle fraction (FPF). VCM DPIs displayed better aerosol dispersion performance compared to CLM DPIs which was related to differences in the physicochemical and particle properties of VCM and CLM. In addition, organic solution advanced co-spray drying particle engineering design was employed to successfully produce co-spray-dried (co-SD) multifunctional microparticulate/nanoparticulate aerosol powder formulations of VCM and CLM with the essential lung surfactant phospholipid, dipalmitoylphosphatidylcholine (DPPC), for controlled release pulmonary nanomedicine delivery as inhalable dry powder aerosols. Formulation optimization was achieved through statistical experimental design of molar ratios of co-SD VCM:DPPC and co-SD CLM:DPPC. XRPD and DSC confirmed that the phospholipid bilayer structure in the solid-state was preserved following spray drying. Co-SD VCM:DPPC and co-SD CLM:DPPC dry powder aerosols demonstrated controlled release of antibiotic drug that was fitted to various

  6. Experimental evidence for formation mechanism of regular circular fringes

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Zhu, R.; Wang, G.; Wang, P.; Li, H.; Zhang, W.; Ren, G.

    2016-10-01

    Laser active suppressing jamming is one of the most effective technologies to cope with optoelectric imaging systems. In the process of carrying out laser disturbing experiment, regular circular fringes often appeared on the detector, besides laser spot converging by optical system. First of all, the formation of circular fringes has been experimentally investigated by using a simple converging lens to replace the complex optical system. Moreover, circular fringes have been simulated based on the interference theory of coherent light. The coherence between the experimental phenomena and the simulated results showed that the formation mechanism of regular circular fringes was the interference effect between reflected light by back surface of lens and directly refractive light on the detector. At last, the visibility of circular fringes has been calculated from 0.05 to 0.22 according to the current plating standard of lens surface and manufacture technique of optoelectric detector.

  7. Fringes' impacts to astrometry and photometry of stars

    NASA Astrophysics Data System (ADS)

    Zheng, Z. J.; Peng, Q. Y.

    2017-04-01

    Fringes often appear in a CCD frame, especially when a thin CCD chip and an R or I filter is used. 88 CCD frames of the two open clusters NGC 2324 and NGC 1664 with a Johnson I filter taken from the 2.4-m telescope at Yunnan Observatory are used to study the fringes' impacts to the astrometry and photometry of stars. A novel technique proposed by Snodgrass and Carry is applied to remove the fringes in each CCD frame. And an appraisal of this technique is performed to estimate fringes' effects on astrometry and photometry of stars. Our results show that the astrometric and photometric precisions of stars can be improved effectively after the removal of fringes, especially for faint stars.

  8. Fringe image processing based on structured light series

    NASA Astrophysics Data System (ADS)

    Gai, Shaoyan; Da, Feipeng; Li, Hongyan

    2009-11-01

    The code analysis of the fringe image is playing a vital role in the data acquisition of structured light systems, which affects precision, computational speed and reliability of the measurement processing. According to the self-normalizing characteristic, a fringe image processing method based on structured light is proposed. In this method, a series of projective patterns is used when detecting the fringe order of the image pixels. The structured light system geometry is presented, which consist of a white light projector and a digital camera, the former projects sinusoidal fringe patterns upon the object, and the latter acquires the fringe patterns that are deformed by the object's shape. Then the binary images with distinct white and black strips can be obtained and the ability to resist image noise is improved greatly. The proposed method can be implemented easily and applied for profile measurement based on special binary code in a wide field.

  9. Hierarchical fringe tracker to co-phase and coherence very large optical interferometers

    NASA Astrophysics Data System (ADS)

    Petrov, Romain G.; Boskri, Abdelkarim; Bresson, Yves; Agabi, Karim; Folcher, Jean-Pierre; Elhalkouj, Thami; Lagarde, Stephane; Benkhaldoum, Zouhair

    2016-08-01

    The full scientific potential of the VLTI with its second generation instruments MATISSE and GRAVITY require fringe tracking up to magnitudes K>14 with the UTs and K>10 with the ATs. The GRAVITY fringe tracker (FT) will be limited to K 10.5 with UTs and K 7.5 with ATs, for fundamental conceptual reasons: the flux of each telescope is distributed among 3 cophasing pairs and then among 5 spectral channels for coherencing. To overcome this limit we propose a new FT concept, called Hierarchical Fringe Tracker (HFT) that cophase pairs of apertures with all the flux from two apertures and only one spectral channel. When the pair is cophased, most of the flux is transmitted as if it was produced by an unique single mode beam and then used to cophase pairs of pairs and then pairs of groups. At the deeper level, the flux is used in an optimized dispersed fringe device for coherencing. On the VLTI such a system allows a gain of about 3 magnitudes over the GRAVITY FT. On interferometers with more apertures such as CHARA (6 telescopes) or a future Planet Formation Imager (12 to 20 telescopes), the HFT would be even more decisive, as its performance does not decrease with the number of apertures. It would allow building a PFI reaching a coherent magnitude H 10 with 16 apertures with diameters smaller than 2 m. We present the HFT concept, the first steps of its feasibility demonstration from computer simulations and the optical design of a 4 telescopes HFT prototype.

  10. Adaptive DFT-based Interferometer Fringe Tracking

    NASA Technical Reports Server (NTRS)

    Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

    2004-01-01

    An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) observatory at Mt. Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on off-line data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse.

  11. Magnetic fields dispersed by high-voltage power lines: an advanced evaluation method based on 3-D models of electrical lines and the territory.

    PubMed

    Andreuccetti, D; Zoppetti, N

    2004-01-01

    An advanced numerical evaluation tool is proposed for calculating the magnetic flux density dispersed by high-voltage power lines. When compared to existing software packages based on the application of standardized methods, this tool turned out to be particularly suitable for making accurate evaluations on vast portions of the territory, especially when the contribution of numerous aerial and/or underground lines must be taken into account. The aspects of the tool of greatest interest are (1) the interaction with an electronic archive of power lines, from which all the information necessary for the calculation is obtained; (2) the use of three-dimensional models of both the power lines and the territory crossed by these; (3) the direct interfacing with electronic cartography; and finally (4) the use of a representation procedure for the results that is based on contour maps. The tool had proven to be very useful especially for Environmental Impact Assessment procedures relative to new power lines.

  12. Design, Characterization, and Aerosol Dispersion Performance Modeling of Advanced Spray-Dried Microparticulate/Nanoparticulate Mannitol Powders for Targeted Pulmonary Delivery as Dry Powder Inhalers

    PubMed Central

    Li, Xiaojian; Vogt, Frederick G.; Hayes, Don

    2014-01-01

    Abstract Background: The purpose was to design and characterize inhalable microparticulate/nanoparticulate dry powders of mannitol with essential particle properties for targeted dry powder delivery for cystic fibrosis mucolytic treatment by dilute organic solution spray drying, and, in addition, to tailor and correlate aerosol dispersion performance delivered as dry powder inhalers based on spray-drying conditions and solid-state physicochemical properties. Methods: Organic solution advanced spray drying from dilute solution followed by comprehensive solid-state physicochemical characterization and in vitro dry powder aerosolization were used. Results: The particle size distribution of the spray-dried (SD) powders was narrow, unimodal, and in the range of ∼500 nm to 2.0 μm. The particles possessed spherical particle morphology, relatively smooth surface morphology, low water content and vapor sorption (crystallization occurred at exposure above 65% relative humidity), and retention of crystallinity by polymorphic interconversion. The emitted dose, fine particle fraction (FPF), and respirable fraction (RF) were all relatively high. The mass median aerodynamic diameters were below 4 μm for all SD mannitol aerosols. Conclusion: The in vitro aerosol deposition stage patterns could be tailored based on spray-drying pump rate. Positive linear correlation was observed between both FPF and RF values with spray-drying pump rates. The interplay between various spray-drying conditions, particle physicochemical properties, and aerosol dispersion performance was observed and examined, which enabled tailoring and modeling of high aerosol deposition patterns. PMID:24502451

  13. Advanced liquefaction using coal swelling and catalyst dispersion techniques. Quarterly technical progress report, July--September 1992

    SciTech Connect

    Curtis, C.W.; Gutterman, C.; Chander, S.

    1992-12-31

    The experimental study of coal swelling ratios have been determined with a wide variety of solvents. Only marginal levels of coal swelling were observed for the hydrocarbon solvents, but high levels were found with solvents having heteroatom functionality. Blends were superior to pure solvents. The activity of various catalyst precursors for pyrene hydrogenation and coal conversion was measured. Higher coal conversions were observed for the S0{sub 2}-treated coal than the raw coal, regardless of catalyst type. Coal conversions were highest for Molyvan-L, molybdenum naphthenate, and nickel octoate, respectively. Bottoms processing consists of a combination of the ASCOT process coupling solvent deasphalting with delayed coking. Initial results indicate that a blend of butane and pentane used near the critical temperature of butane is the best solvent blend for producing a yield/temperature relationship of proper sensitivity and yet retaining an asphalt phase of reasonable viscosity. The literature concerning coal swelling, both alone and in combination with coal liquefaction, and the use of dispersed or unsupported catalysts in coal liquefaction has been updated.

  14. Advanced liquefaction using coal swelling and catalyst dispersion techniques. Quarterly technical progress report, April--June 1992

    SciTech Connect

    Curtis, C.W.; Gutterman, C.; Chander, S.

    1992-08-26

    Research in this project centers upon developing a new approach to the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates all aspects of the coal liquefaction process including coal selection, pretreatment, coal swelling with catalyst impregnation, coal liquefaction experimentation, product recovery with characterization, alternate bottoms processing, and a technical assessment including an economic evaluation. The project is being carried out under contract to the United States Department of Energy. On May 28, 1992, the Department of Energy authorized starting the experimental aspects of this projects; therefore, experimentation at Amoco started late in this quarterly report period. Research contracts with Auburn University, Pennsylvania State University, and Foster Wheeler Development Corporation were signed during June, 1992, so their work was just getting underway. Their work will be summarized in future quarterly reports. A set of coal samples were sent to Hazen Research for beneficiation. The samples were received and have been analyzed. The literature search covering coal swelling has been up-dated, and preliminary coal swelling experiments were carried out. Further swelling experimentation is underway. An up-date of the literature on the liquefaction of coal using dispersed catalysts is nearing completion; it will be included in the next quarterly report.

  15. Colloid mobilization and transport during capillary fringe fluctuations.

    PubMed

    Aramrak, Surachet; Flury, Markus; Harsh, James B; Zollars, Richard L

    2014-07-01

    Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead-filled column. We studied four specific conditions: (1) colloids suspended in the aqueous phase, (2) colloids attached to the glass beads in an initially wet porous medium, (3) colloids attached to the glass beads in an initially dry porous medium, and (4) colloids suspended in the aqueous phase with the presence of a static air bubble. Confocal images confirmed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively charged colloids did not attach to static air-bubbles, but hydrophobic negatively charged and hydrophilic positively charged colloids did. Our results demonstrate that capillary fringe fluctuations are an effective means for colloid mobilization.

  16. INTERFERENCE FRINGES OF SOLAR ACOUSTIC WAVES AROUND SUNSPOTS

    SciTech Connect

    Chou, Dean-Yi; Zhao Hui; Yang, Ming-Hsu; Liang, Zhi-Chao

    2012-10-20

    Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

  17. Advanced Wavefront Sensing and Control Testbed (AWCT)

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Basinger, Scott A.; Diaz, Rosemary T.; Gappinger, Robert O.; Tang, Hong; Lam, Raymond K.; Sidick, Erkin; Hein, Randall C.; Rud, Mayer; Troy, Mitchell

    2010-01-01

    The Advanced Wavefront Sensing and Control Testbed (AWCT) is built as a versatile facility for developing and demonstrating, in hardware, the future technologies of wave front sensing and control algorithms for active optical systems. The testbed includes a source projector for a broadband point-source and a suite of extended scene targets, a dispersed fringe sensor, a Shack-Hartmann camera, and an imaging camera capable of phase retrieval wavefront sensing. The testbed also provides two easily accessible conjugated pupil planes which can accommodate the active optical devices such as fast steering mirror, deformable mirror, and segmented mirrors. In this paper, we describe the testbed optical design, testbed configurations and capabilities, as well as the initial results from the testbed hardware integrations and tests.

  18. Online fringe projection profilometry based on scale-invariant feature transform

    NASA Astrophysics Data System (ADS)

    Li, Hongru; Feng, Guoying; Yang, Peng; Wang, Zhaomin; Zhou, Shouhuan; Asundi, Anand

    2016-08-01

    An online fringe projection profilometry (OFPP) based on scale-invariant feature transform (SIFT) is proposed. Both rotary and linear models are discussed. First, the captured images are enhanced by "retinex" theory for better contrast and an improved reprojection technique is carried out to rectify pixel size while keeping the right aspect ratio. Then the SIFT algorithm with random sample consensus algorithm is used to match feature points between frames. In this process, quick response code is innovatively adopted as a feature pattern as well as object modulation. The characteristic parameters, which include rotation angle in rotary OFPP and rectilinear displacement in linear OFPP, are calculated by a vector-based solution. Moreover, a statistical filter is applied to obtain more accurate values. The equivalent aligned fringe patterns are then extracted from each frame. The equal step algorithm, advanced iterative algorithm, and principal component analysis are eligible for phase retrieval according to whether the object moving direction accords with the fringe direction or not. The three-dimensional profile of the moving object can finally be reconstructed. Numerical simulations and experimental results verified the validity and feasibility of the proposed method.

  19. Assessing increasing susceptibility to wildfire at the wildland-urban fringe in the western United States

    NASA Astrophysics Data System (ADS)

    Kinoshita, A. M.; Hogue, T. S.

    2013-05-01

    Much of the western U.S. is increasingly susceptible to wildfire activity due to drier conditions, elevated fuel loads, and expanding urbanization. As population increases, development pushes the urban boundary further into wildlands, creating more potential for human interaction at the wildland-urban interface (WUI), primarily from human ignitions and fire suppression policies. The immediate impacts of wildfires include vulnerability to debris flows, flooding, and impaired water quality. Fires also alter longer-term hydrological and ecosystem behavior. The current study utilizes geospatial datasets to investigate historical wildfire size and frequency relative to the WUI for a range of cities across western North America. California, the most populous state in the U.S., has an extensive fire history. The decennial population and acres burned for four major counties (Los Angeles, San Bernardino, San Diego, and Shasta) in California show that increasing wildfire size and frequency follow urbanization trends, with high correlation between the last decade of burned area, urban-fringe proximity, and increasing population. Ultimately, results will provide information on urban fringe communities that are most vulnerable to the risks associated with wildfire and post-fire impacts. In light of evolving land use policies (i.e. forest management and treatment, development at the urban-fringe) and climate change, it is critical to advance our knowledge of the implications that these conditions pose to urban centers, communicate risks to the public, and ultimately provide guidance for wildfire management.

  20. Time average vibration fringe analysis using Hilbert transformation

    SciTech Connect

    Kumar, Upputuri Paul; Mohan, Nandigana Krishna; Kothiyal, Mahendra Prasad

    2010-10-20

    Quantitative phase information from a single interferogram can be obtained using the Hilbert transform (HT). We have applied the HT method for quantitative evaluation of Bessel fringes obtained in time average TV holography. The method requires only one fringe pattern for the extraction of vibration amplitude and reduces the complexity in quantifying the data experienced in the time average reference bias modulation method, which uses multiple fringe frames. The technique is demonstrated for the measurement of out-of-plane vibration amplitude on a small scale specimen using a time average microscopic TV holography system.

  1. Fringes of equal tangential inclination by curvature-induced birefringence

    NASA Astrophysics Data System (ADS)

    Medhat, M.; Hendawy, N. I.; Zaki, A. A.

    2003-02-01

    A new kind of interference fringes, fringes of equal tangential inclination by curvature-induced birefringence, is presented. These are two-beam interference fringes produced by bending a thin sheet of birefringent material into a part of an exact cylinder such that the curvature is constant. Due to this curvature there is a uniform birefringence being induced. The change in birefringence induced by applying different radii of curvatures to a Fortepan sheet is measured. The stored (fixed) or natural birefringence of this sheet is deduced.

  2. Generalized Fourier analysis for phase retrieval of fringe pattern.

    PubMed

    Zhong, Jingang; Weng, Jiawen

    2010-12-20

    A generalized Fourier analysis, by use of an adaptive multiscale windowed Fourier transform (AWFT), has been presented for the phase retrieval of fringe patterns. The Fourier transform method can be considered as a special case of AWFT method with a maximum window. The instantaneous frequency of the local signal is introduced to estimate whether the condition for separating the first spectrum component is satisfied for the phase retrieval of fringe patterns. The adaptive window width for this algorithm is determined by the length of the local stationary fringe pattern in order to balance the frequency and space resolution. The local stationary length of fringe pattern is defined as the signal satisfying the condition that whose first spectrum component is separated from all the other spectra within the local spatial area. In comparison with Fourier transform, fixed windowed Fourier transform and wavelet transform in numerical simulation and experiment, the adaptive multiscale windowed Fourier transform can present more accurate results of phase retrieval.

  3. 29 CFR 4.52 - Fringe benefit determinations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to § 4.51(b) that a single fringe benefit rate is paid with respect to a majority of the workers in a... per hour. Generally, these contracts are large base support contracts, contracts requiring...

  4. 29 CFR 4.52 - Fringe benefit determinations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... to § 4.51(b) that a single fringe benefit rate is paid with respect to a majority of the workers in a... per hour. Generally, these contracts are large base support contracts, contracts requiring...

  5. Ghost fringe removal techniques using Lissajous data presentation

    NASA Astrophysics Data System (ADS)

    Erskine, David; Eggert, Jon; Celliers, Peter; Hicks, Damien

    2017-01-01

    Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can obscure and complicate the true signal. Accurately removing this so-called ghost component is essential for achieving high accuracy EOS measurements, especially when the true signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing the raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the true center of this curve, since the ghost contribution is solved by a translation in the complex plane that recenters the Lissajous. For continuous velocity histories, we find that plotting the fringe visibility vs nonfringing intensity and optimizing linearity is a valuable tool for determining the proper ghost offsets. For discontinuous velocity histories, we have developed methods which relate the results of two VISARs having different velocity per fringe proportionalities to find the ghost offset.

  6. Minimizing Fizeau Fringes During the Contact Printing of Diffraction Gratings

    SciTech Connect

    Ciarlo, D; Rushford, M; Kuzmenko, P; Ge, J

    2001-04-27

    An index matching fluid has been used to minimize the effect of interference fringes which develop when contact printing diffraction gratings on silicon wafers. These fringes are the result of interference effects when there is a small but uneven gap between the photomask and resist surface. They are especially troublesome when printing and etching large area, coarse diffraction gratings on the surface of silicon wafers and silicon disks.

  7. Improved thrust calculations of active magnetic bearings considering fringing flux

    NASA Astrophysics Data System (ADS)

    Jang, Seok-Myeong; Kim, Kwan-Ho; Ko, Kyoung-Jin; Choi, Ji-Hwan; Sung, So-Young; Lee, Yong-Bok

    2012-04-01

    A methodology for deriving fringing permeance in axisymmetric devices such as active thrust magnetic bearings (ATMBs) is presented. The methodology is used to develop an improved equivalent magnetic circuit (EMC) for ATMBs, which considers the fringing effect. This EMC was used to characterize the force between the housing and mover and the dependence of thrust and inductance on the air gap and input current, respectively. These characteristics were validated by comparison with those obtained by the finite element method and in experiments.

  8. NEW APPROACHES: Demonstration of a dancing interference fringe

    NASA Astrophysics Data System (ADS)

    Kagawa, K.; Yamanaka, H.; Yokoi, S.; Hattori, H.

    1997-11-01

    A unique and amusing piece of laser art is proposed for use in physics education. It is shown that a dynamic and beautiful interference fringe can be produced when a He - Ne laser beam illuminates a droplet, which is called Brandy's tear, on a glass surface. This interference fringe can be explained in terms of the interference of multiple spherical waves scattered by the droplet. This kind of demonstration experiment is very helpful for exciting students' curiosity.

  9. Method and apparatus for fringe-scanning chromosome analysis

    DOEpatents

    Norgren, R.M.; Gray, J.W.; Hirschfeld, T.B.

    1983-08-31

    Apparatus and method are provided for analyzing sub-micron-sized features of microscopic particles. Two central features of the invention are (1) constraining microscopic particles to flow with substantially constant orientation through a predetermined interference fringe pattern, and (2) estimating particle structure by analyzing its fringe profile. The invention allows nearly an order of magnitude higher resolution of chromosome structure than possible with currently available flow system techniques. The invention allows rapid and accurate flow karyotyping of chromosomes.

  10. Complex phase tracing method for fringe pattern analysis.

    PubMed

    Kozłowski, J; Serra, G

    1999-04-10

    We present what we believe to be a novel complex phase tracing method for fringe pattern analysis related to the phase-locked loop idea. The image with deformed complex fringes is analyzed with lexicographic scansion that leads directly to the investigated phase without unwrapping. Robustness of the procedure is ensured by the delay mechanism in the process of calculating the reference value. A numerical model and examples of application of the presented method are given.

  11. Method and apparatus for fringe-scanning chromosome analysis

    DOEpatents

    Norgren, Richard M.; Gray, Joe W.; Hirschfeld, Tomas B.

    1986-01-01

    Apparatus and method are provided for analyzing sub-micron-sized features of microscopic particles. Two central features of the invention are (1) constraining microscopic particles to flow with substantially constant orientation through a predetermined interference fringe pattern, and (2) estimating particle structure by analyzing its fringe profile. The invention allows nearly an order of magnitude higher resolution of chromosome structure than possible with currently available flow system techniques. The invention allows rapid and accurate flow karyotyping of chromosomes.

  12. Fringe biasing: A variance reduction technique for optically thick meshes

    SciTech Connect

    Smedley-Stevenson, R. P.

    2013-07-01

    Fringe biasing is a stratified sampling scheme applicable to Monte Carlo thermal radiation transport codes. The thermal emission source in optically thick cells is partitioned into separate contributions from the cell interiors (where the likelihood of the particles escaping the cells is virtually zero) and the 'fringe' regions close to the cell boundaries. Thermal emission in the cell interiors can now be modelled with fewer particles, the remaining particles being concentrated in the fringes so that they are more likely to contribute to the energy exchange between cells. Unlike other techniques for improving the efficiency in optically thick regions (such as random walk and discrete diffusion treatments), fringe biasing has the benefit of simplicity, as the associated changes are restricted to the sourcing routines with the particle tracking routines being unaffected. This paper presents an analysis of the potential for variance reduction achieved from employing the fringe biasing technique. The aim of this analysis is to guide the implementation of this technique in Monte Carlo thermal radiation codes, specifically in order to aid the choice of the fringe width and the proportion of particles allocated to the fringe (which are interrelated) in multi-dimensional simulations, and to confirm that the significant levels of variance reduction achieved in simulations can be understood by studying the behaviour for simple test cases. The variance reduction properties are studied for a single cell in a slab geometry purely absorbing medium, investigating the accuracy of the scalar flux and current tallies on one of the interfaces with the surrounding medium. (authors)

  13. Ghost fringe removal techniques using Lissajous data presentation

    DOE PAGES

    Erskine, David J.; Eggert, J. H.; Celliers, P. M.; ...

    2016-03-14

    A VISAR (Velocity Interferometer System for Any Reflector) is a Dopplervelocity interferometer which is an important optical diagnostic in shockwave experiments at the national laboratories, used to measureequation of state(EOS) of materials under extreme conditions. Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can distort and obscure the true velocity signal. When accurately removing this so-called ghost artifact component is essential for achieving high accuracy EOSmeasurements, especially when the true light signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing themore » raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the proper center of this path, even under time varying intensity which can shift the perceived center. Moreover, the ghost contribution is then solved by a simple translation in the complex plane that recenters the Lissajous path. For continuous velocity histories, we find that plotting the fringe magnitude vs nonfringing intensity and optimizing linearity is an invaluable tool for determining accurate ghost offsets. For discontinuous velocity histories, we have developed graphically inspired methods which relate the results of two VISARs having different velocity per fringe proportionalities or assumptions of constant fringe magnitude to find the ghost offset. The technique can also remove window reflection artifacts in generic interferometers, such as in the metrology of surfaces.« less

  14. Ghost fringe removal techniques using Lissajous data presentation

    SciTech Connect

    Erskine, David J.; Eggert, J. H.; Celliers, P. M.; Hicks, D. G.

    2016-03-14

    A VISAR (Velocity Interferometer System for Any Reflector) is a Dopplervelocity interferometer which is an important optical diagnostic in shockwave experiments at the national laboratories, used to measureequation of state(EOS) of materials under extreme conditions. Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can distort and obscure the true velocity signal. When accurately removing this so-called ghost artifact component is essential for achieving high accuracy EOSmeasurements, especially when the true light signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing the raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the proper center of this path, even under time varying intensity which can shift the perceived center. Moreover, the ghost contribution is then solved by a simple translation in the complex plane that recenters the Lissajous path. For continuous velocity histories, we find that plotting the fringe magnitude vs nonfringing intensity and optimizing linearity is an invaluable tool for determining accurate ghost offsets. For discontinuous velocity histories, we have developed graphically inspired methods which relate the results of two VISARs having different velocity per fringe proportionalities or assumptions of constant fringe magnitude to find the ghost offset. The technique can also remove window reflection artifacts in generic interferometers, such as in the metrology of surfaces.

  15. Ghost fringe removal techniques using Lissajous data presentation

    NASA Astrophysics Data System (ADS)

    Erskine, David J.; Eggert, J. H.; Celliers, P. M.; Hicks, D. G.

    2016-03-01

    A VISAR (Velocity Interferometer System for Any Reflector) is a Doppler velocity interferometer which is an important optical diagnostic in shockwave experiments at the national laboratories, used to measure equation of state (EOS) of materials under extreme conditions. Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can distort and obscure the true velocity signal. Accurately removing this so-called ghost artifact component is essential for achieving high accuracy EOS measurements, especially when the true light signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing the raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the proper center of this path, even under time varying intensity which can shift the perceived center. The ghost contribution is then solved by a simple translation in the complex plane that recenters the Lissajous path. For continuous velocity histories, we find that plotting the fringe magnitude vs nonfringing intensity and optimizing linearity is an invaluable tool for determining accurate ghost offsets. For discontinuous velocity histories, we have developed graphically inspired methods which relate the results of two VISARs having different velocity per fringe proportionalities or assumptions of constant fringe magnitude to find the ghost offset. The technique can also remove window reflection artifacts in generic interferometers, such as in the metrology of surfaces.

  16. Ghost fringe removal techniques using Lissajous data presentation.

    PubMed

    Erskine, David J; Eggert, J H; Celliers, P M; Hicks, D G

    2016-03-01

    A VISAR (Velocity Interferometer System for Any Reflector) is a Doppler velocity interferometer which is an important optical diagnostic in shockwave experiments at the national laboratories, used to measure equation of state (EOS) of materials under extreme conditions. Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can distort and obscure the true velocity signal. Accurately removing this so-called ghost artifact component is essential for achieving high accuracy EOS measurements, especially when the true light signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing the raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the proper center of this path, even under time varying intensity which can shift the perceived center. The ghost contribution is then solved by a simple translation in the complex plane that recenters the Lissajous path. For continuous velocity histories, we find that plotting the fringe magnitude vs nonfringing intensity and optimizing linearity is an invaluable tool for determining accurate ghost offsets. For discontinuous velocity histories, we have developed graphically inspired methods which relate the results of two VISARs having different velocity per fringe proportionalities or assumptions of constant fringe magnitude to find the ghost offset. The technique can also remove window reflection artifacts in generic interferometers, such as in the metrology of surfaces.

  17. VLTI First Fringes with Two Auxiliary Telescopes at Paranal

    NASA Astrophysics Data System (ADS)

    2005-03-01

    World's Largest Interferometer with Moving Optical Telescopes on Track Summary The Very Large Telescope Interferometer (VLTI) at Paranal Observatory has just seen another extension of its already impressive capabilities by combining interferometrically the light from two relocatable 1.8-m Auxiliary Telescopes. Following the installation of the first Auxiliary Telescope (AT) in January 2004 (see ESO PR 01/04), the second AT arrived at the VLT platform by the end of 2004. Shortly thereafter, during the night of February 2 to 3, 2005, the two high-tech telescopes teamed up and quickly succeeded in performing interferometric observations. This achievement heralds an era of new scientific discoveries. Both Auxiliary Telescopes will be offered from October 1, 2005 to the community of astronomers for routine observations, together with the MIDI instrument. By the end of 2006, Paranal will be home to four operational ATs that may be placed at 30 different positions and thus be combined in a very large number of ways ("baselines"). This will enable the VLTI to operate with enormous flexibility and, in particular, to obtain extremely detailed (sharp) images of celestial objects - ultimately with a resolution that corresponds to detecting an astronaut on the Moon. PR Photo 07a/05: Paranal Observing Platform with AT1 and AT2 PR Photo 07b/05: AT1 and AT2 with Open Domes PR Photo 07c/05: Evening at Paranal with AT1 and AT2 PR Photo 07d/05: AT1 and AT2 under the Southern Sky PR Photo 07e/05: First Fringes with AT1 and AT2 PR Video Clip 01/05: Two ATs at Paranal (Extract from ESO Newsreel 15) A Most Advanced Device ESO PR Video 01/05 ESO PR Video 01/05 Two Auxiliary Telescopes at Paranal [QuickTime: 160 x 120 pix - 37Mb - 4:30 min] [QuickTime: 320 x 240 pix - 64Mb - 4:30 min] ESO PR Photo 07a/05 ESO PR Photo 07a/05 [Preview - JPEG: 493 x400 pix - 44k] [Normal - JPEG: 985 x 800 pix - 727k] [HiRes - JPEG: 5000 x 4060 pix - 13.8M] Captions: ESO PR Video Clip 01/05 is an extract from

  18. Comparison of infinite and wedge fringe settings in Mach Zehnder interferometer for temperature field measurement

    SciTech Connect

    Haridas, Divya; P, Vibin Antony; Sajith, V.; Sobhan, C. B.

    2014-10-15

    Interferometric method, which utilizes the interference of coherent light beams, is used to determine the temperature distribution in the vicinity of a vertical heater plate. The optical components are arranged so as to obtain wedge fringe and infinite fringe patterns and isotherms obtained in each case were compared. In wedge fringe setting, image processing techniques has been used for obtaining isotherms by digital subtraction of initial parallel fringe pattern from deformed fringe pattern. The experimental results obtained are compared with theoretical correlations. The merits and demerits of the fringe analysis techniques are discussed on the basis of the experimental results.

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

    PubMed

    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.

  20. Phase errors due to speckles in laser fringe projection.

    PubMed

    Rosendahl, Sara; Hällstig, Emil; Gren, Per; Sjödahl, Mikael

    2010-04-10

    When measuring a three-dimensional shape with triangulation and projected interference fringes it is of interest to reduce speckle contrast without destroying the coherence of the projected light. A moving aperture is used to suppress the speckles and thereby reduce the phase error in the fringe image. It is shown that the phase error depends linearly on the ratio between the speckle contrast and the modulation of the fringes. In this investigation the spatial carrier method was used to extract the phase, where the phase error also depends on filtering the Fourier spectrum. An analytical expression for the phase error is derived. Both the speckle reduction and the theoretical expressions for the phase error are verified by simulations and experiments. It was concluded that a movement of the aperture by three aperture diameters during exposure of the image reduces the speckle contrast and hence the phase error by 60%. In the experiments, a phase error of 0.2 rad was obtained.

  1. Characterization and aerosol dispersion performance of advanced spray-dried chemotherapeutic PEGylated phospholipid particles for dry powder inhalation delivery in lung cancer.

    PubMed

    Meenach, Samantha A; Anderson, Kimberly W; Zach Hilt, J; McGarry, Ronald C; Mansour, Heidi M

    2013-07-16

    Pulmonary inhalation chemotherapeutic drug delivery offers many advantages for lung cancer patients in comparison to conventional systemic chemotherapy. Inhalable particles are advantageous in their ability to deliver drug deep in the lung by utilizing optimally sized particles and higher local drug dose delivery. In this work, spray-dried and co-spray dried inhalable lung surfactant-mimic PEGylated lipopolymers as microparticulate/nanoparticulate dry powders containing paclitaxel were rationally designed via organic solution advanced spray drying (no water) in closed-mode from dilute concentration feed solution. Dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine poly(ethylene glycol) (DPPE-PEG) with varying PEG chain length were mixed with varying amounts of paclitaxel in methanol to produce co-spray dried microparticles and nanoparticles. Scanning electron microscopy showed the spherical particle morphology of the inhalable particles. Thermal analysis and X-ray powder diffraction confirmed the retention of the phospholipid bilayer structure in the solid-state following spray drying, the degree of solid-state molecular order, and solid-state phase transition behavior. The residual water content of the particles was very low as quantified analytically Karl Fisher titration. The amount of paclitaxel loaded into the particles was quantified which indicated high encapsulation efficiencies (43-99%). Dry powder aerosol dispersion performance was measured in vitro using the Next Generation Impactor (NGI) coupled with the Handihaler dry powder inhaler device and showed mass median aerodynamic diameters in the range of 3.4-7 μm. These results demonstrate that this novel microparticulate/nanoparticulate chemotherapeutic PEGylated phospholipid dry powder inhalation aerosol platform has great potential in lung cancer drug delivery.

  2. Microstructural Characterization of a Mg Matrix U-Mo Dispersion Fuel Plate Irradiated in the Advanced Test Reactor to High Fission Density: SEM Results

    NASA Astrophysics Data System (ADS)

    Keiser, Dennis D.; Jue, Jan-Fong; Miller, Brandon D.; Gan, Jian; Robinson, Adam B.; Medvedev, Pavel G.; Madden, James W.; Moore, Glenn A.

    2016-06-01

    Low-enriched (U-235 <20 pct) U-Mo dispersion fuel is being developed for use in research and test reactors. In most cases, fuel plates with Al or Al-Si alloy matrices have been tested in the Advanced Test Reactor to support this development. In addition, fuel plates with Mg as the matrix have also been tested. The benefit of using Mg as the matrix is that it potentially will not chemically interact with the U-Mo fuel particles during fabrication or irradiation, whereas with Al and Al-Si alloys such interactions will occur. Fuel plate R9R010 is a Mg matrix fuel plate that was aggressively irradiated in ATR. This fuel plate was irradiated as part of the RERTR-8 experiment at high temperature, high fission rate, and high power, up to high fission density. This paper describes the results of the scanning electron microscopy (SEM) analysis of an irradiated fuel plate using polished samples and those produced with a focused ion beam. A follow-up paper will discuss the results of transmission electron microscopy (TEM) analysis. Using SEM, it was observed that even at very aggressive irradiation conditions, negligible chemical interaction occurred between the irradiated U-7Mo fuel particles and Mg matrix; no interconnection of fission gas bubbles from fuel particle to fuel particle was observed; the interconnected fission gas bubbles that were observed in the irradiated U-7Mo particles resulted in some transport of solid fission products to the U-7Mo/Mg interface; the presence of microstructural pathways in some U-9.1 Mo particles that could allow for transport of fission gases did not result in the apparent presence of large porosity at the U-7Mo/Mg interface; and, the Mg-Al interaction layers that were present at the Mg matrix/Al 6061 cladding interface exhibited good radiation stability, i.e. no large pores.

  3. Topometry of technical and biological objects by fringe projection

    NASA Astrophysics Data System (ADS)

    Windecker, R.; Tiziani, H. J.

    1995-07-01

    Fringe projection is a fast and accurate technique for obtaining the topometry of a wide range of surfaces. Here some features of the principle are described, together with the possibilities of adapting this technique for the measurement of vaulted surfaces. We discuss various methods of phase evaluation and compare them with simulated computer data to obtain the resolution limits. Under certain restrictions a semispatial algorithm, called the modified Fourier analysis algorithm, gives the best results. One special subject of interest is the application of fringe projection for the measurement of the three-dimensional surface of the cornea. First results of in vivo measurements are presented.

  4. Phase extraction from fringe pattern via light propagation.

    PubMed

    Zhu, Wenhua; Chen, Lei; Zheng, Donghui; Zhang, Rui; Han, Zhigang

    2017-01-10

    A phase demodulation method via light propagation is proposed, where one or two fringe patterns are viewed as the superposition of complex amplitudes, and then the phase is reconstructed by separating the light field via light propagation. Simulation and experimental results indicated that the proposed method can extract the phase from a single shot effectively, thereby realizing dynamic phase retrieval. In addition, the accuracy of phase reconstruction can be improved by adding another fringe pattern with an unknown phase shift. The carrier requirement is relatively low, and, thus, the proposed method can be applied to the measurements with an environment disturbance, an inaccurate phase shift, and the requirement of a high speed capture.

  5. Analytical expressions for fringe fields in multipole magnets

    NASA Astrophysics Data System (ADS)

    Muratori, B. D.; Jones, J. K.; Wolski, A.

    2015-06-01

    Fringe fields in multipole magnets can have a variety of effects on the linear and nonlinear dynamics of particles moving along an accelerator beam line. An accurate model of an accelerator must include realistic models of the magnet fringe fields. Fringe fields for dipoles are well understood and can be modeled at an early stage of accelerator design in such codes as mad8, madx, gpt or elegant. Existing techniques for quadrupole and higher order multipoles rely either on the use of a numerical field map, or on a description of the field in the form of a series expansion about a chosen axis. Usually, it is not until the later stages of a design project that such descriptions (based on magnet modeling or measurement) become available. Furthermore, series expansions rely on the assumption that the beam travels more or less on axis throughout the beam line; but in some types of machines (for example, Fixed Field Alternating Gradients or FFAGs) this is not a good assumption. Furthermore, some tracking codes, such as gpt, use methods for including space charge effects that require fields to vary smoothly and continuously along a beam line: in such cases, realistic fringe field models are of significant importance. In this paper, a method for constructing analytical expressions for multipole fringe fields is presented. Such expressions allow fringe field effects to be included in beam dynamics simulations from the start of an accelerator design project, even before detailed magnet design work has been undertaken. The magnetostatic Maxwell equations are solved analytically and a solution that fits all orders of multipoles is derived. Quadrupole fringe fields are considered in detail as these are the ones that give the strongest effects. The analytic expressions for quadrupole fringe fields are compared with data obtained from numerical modeling codes in two cases: a magnet in the high luminosity upgrade of the Large Hadron Collider inner triplet, and a magnet in the

  6. Modern marine dolomite cement in a north Jamaican fringing reef

    SciTech Connect

    Mitchell, J.T.; Land, L.S.; Miser, D.E.

    1987-06-01

    Minor quantities of ordered dolomite (..delta../sup 18/O = +2.0 per thousand PDB; composition = Ca/sub 1.22/Mg/sub 0.78/ (CO/sub 3/)/sub 2/) have formed from near-normal seawater in a subtidal hardground as part of a modern fringing coral reef. Crystals 5 ..mu..m in diameter precipitated within the past 1.8 ka in the form of syntaxial fringes on Mg-calcite marine cements and skeletal allochems. The crystals have a fine modulated microstructure and c reflections, both apparently formed during crystal growth

  7. Fringe pattern demodulation with a two-frame digital phase-locked loop algorithm.

    PubMed

    Gdeisat, Munther A; Burton, David R; Lalor, Michael J

    2002-09-10

    A novel technique called a two-frame digital phase-locked loop for fringe pattern demodulation is presented. In this scheme, two fringe patterns with different spatial carrier frequencies are grabbed for an object. A digital phase-locked loop algorithm tracks and demodulates the phase difference between both fringe patterns by employing the wrapped phase components of one of the fringe patterns as a reference to demodulate the second fringe pattern. The desired phase information can be extracted from the demodulated phase difference. We tested the algorithm experimentally using real fringe patterns. The technique is shown to be suitable for noncontact measurement of objects with rapid surface variations, and it outperforms the Fourier fringe analysis technique in this aspect. Phase maps produced withthis algorithm are noisy in comparison with phase maps generated with the Fourier fringe analysis technique.

  8. Effects of the Tax Treatment of Fringe Benefits on Labor Market Segmentation.

    ERIC Educational Resources Information Center

    Scott, Frank A.; And Others

    1989-01-01

    Argues that the provision of the same fringe benefits for all workers promotes labor market segmentation by inducing workers to sort themselves across the economy according to their demand for fringe benefits. (JOW)

  9. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... perception of the value of a fringe benefit is not relevant to the determination of a fringe benefit's fair... employee and the employer must be disregarded. Also, the employee's subjective perception of the value...

  10. 26 CFR 1.132-5 - Working condition fringes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Further that the employee drives the vehicle 6,000 miles for his employer's business and 2,000 miles for... condition fringe, miles accumulated on the vehicle by all employees of the employer during the period in...,000 additional miles on the vehicle (while the employee is not in the automobile). In this case,...

  11. Fringe Benefits for Non-Teaching Employees in American Universities.

    ERIC Educational Resources Information Center

    Smith, Edwin R.; And Others

    A survey was undertaken by the Office of Institutional Research and the Department of Education Administration at West Virginia University to determine the range, alternatives, norms, and other major administration considerations relative to fringe benefits available to nonteaching employees in major American universities. A copy of the…

  12. Improved Goldstein Interferogram Filter Based on Local Fringe Frequency Estimation

    PubMed Central

    Feng, Qingqing; Xu, Huaping; Wu, Zhefeng; You, Yanan; Liu, Wei; Ge, Shiqi

    2016-01-01

    The quality of an interferogram, which is limited by various phase noise, will greatly affect the further processes of InSAR, such as phase unwrapping. Interferometric SAR (InSAR) geophysical measurements’, such as height or displacement, phase filtering is therefore an essential step. In this work, an improved Goldstein interferogram filter is proposed to suppress the phase noise while preserving the fringe edges. First, the proposed adaptive filter step, performed before frequency estimation, is employed to improve the estimation accuracy. Subsequently, to preserve the fringe characteristics, the estimated fringe frequency in each fixed filtering patch is removed from the original noisy phase. Then, the residual phase is smoothed based on the modified Goldstein filter with its parameter alpha dependent on both the coherence map and the residual phase frequency. Finally, the filtered residual phase and the removed fringe frequency are combined to generate the filtered interferogram, with the loss of signal minimized while reducing the noise level. The effectiveness of the proposed method is verified by experimental results based on both simulated and real data. PMID:27886081

  13. 26 CFR 1.132-5 - Working condition fringes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... driver and all passengers of a qualified nonpersonal use vehicle. However, a working condition fringe... passengers of a qualified nonpersonal use vehicle described in § 1.274-5(k)(2)(ii)(L) or (P). (i) (j... employee are— (A) A threat of death or kidnapping of, or serious bodily harm to, the employee or...

  14. Enhanced dynamic range fringe projection for micro-structure characterization

    NASA Astrophysics Data System (ADS)

    Samara, Ayman Mohammad

    We present a solution for one of the main limitations in classical interferometry and fringe projection, which is the dynamic range limitation. The technique is based on real time inverse fringe projection to enhance the dynamic range and increase the vertical resolution without the need of prior information about the test object or the system parameters. The object's form optical path difference map is first measured, and then used to generate inverse fringes to optically filter the low spatial frequency form. The surface finish can then be measured without the impact of the form. A stereo microscope-based fringe projection system was designed, constructed, and used to illustrate the technique. The system was also used to characterize solder bumps with an uncertainty of approximately 10%. Individual solder bumps were also characterized using Zygo's NewView(TM) scanning white light interferometer (SWLI), and the results were compared to measurements on Intel's bump metrology tool. The results show that the SWLI has the lowest uncertainty and maximum repeatability but the lowest measurement speed. Intel's tool has a repeatability of approximately 1% and a measurement speed of about 10 minutes per 100,000 bumps, making it suitable for high volume process control.

  15. 2 CFR 200.431 - Compensation-fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... by the Federal awarding agency. (j)(1) For IHEs only. Fringe benefits in the form of tuition or remission of tuition for individual employees are allowable, provided such benefits are granted in... activities on an equitable basis. Tuition benefits for family members other than the employee are...

  16. Picometer Precision Measurements of Fringe Phase and Wavelengths in MAM

    NASA Astrophysics Data System (ADS)

    Pan, X.; Shao, M.; Goullioud, R.

    2004-12-01

    The Space Interferometry Mission (SIM), a micro-arcsecond astrometry mission, is the only mission, either operational or in planning, that will be capable of measuring the mass of extra-solar planets, mass being the fundamental property that determines whether the planet is capable of holding an Earth-like atmosphere. One of the SIM testbeds at JPL, the Micro-Arcsecond Metrology (MAM) testbed, addresses how to measure interferometer fringe phase and wavelengths accurately at the level of picometers (10-12 m). The MAM testbed uses a pathlength modulation scheme for fringe detection, using ten samples per stroke, with stroke-length close to the wavelength of a spectral channel. The MAM testbed has demonstrated the measurement of optical pathlength delays to picometer precision. Longer strokes (tens of microns) enable both fringe and modulation envelope to be detected, yielding accurate wavelength measurements at the picometer level for the first time. This paper describes the fundamental principles of a new technique for calibration and measurement of fringes for targets that have various spectra, in which effective wavelength varies significantly for different spectral channels. Test results and variations with time are analyzed. Conformation of measurenet accuracy and stability are described in this paper.

  17. 29 CFR 5.29 - Specific fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... amended (S. Rep. No. 963, p. 5). (c) The term “other bona fide fringe benefits” is the so-called “open end... benefits are those common in the construction industry and which are established under a usual fund, plan... considered on its own merits, payments made for travel, subsistence or to industry promotion funds are...

  18. 29 CFR 5.29 - Specific fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... amended (S. Rep. No. 963, p. 5). (c) The term “other bona fide fringe benefits” is the so-called “open end... benefits are those common in the construction industry and which are established under a usual fund, plan... considered on its own merits, payments made for travel, subsistence or to industry promotion funds are...

  19. 29 CFR 5.29 - Specific fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... amended (S. Rep. No. 963, p. 5). (c) The term “other bona fide fringe benefits” is the so-called “open end... benefits are those common in the construction industry and which are established under a usual fund, plan... considered on its own merits, payments made for travel, subsistence or to industry promotion funds are...

  20. Image continuity at different levels of zoom for fringe patterns.

    PubMed

    Abolbashari, Mehrdad; Gerges, Awad S; Davies, Angela; Farahi, Faramarz

    2012-01-02

    Fringe patterns are raw output data from many measurement systems including laser interferometers and moiré systems. For instruments with a range of zoom levels to measure the object at different scales, a technique (algorithm) is needed to combine and/or compare data to obtain information at different levels of details. A technique to keep the continuity of output images both at different levels of zoom and within the same level of zoom is developed and demonstrated. Image registration is used to correlate images, find relative zoom values, and obtain shift between images in the lateral plane. Fringe patterns from a moiré system and a laser interferometer are used as images to be stitched and demonstrate the technique. Interferomteric fringes are used to find the required parameters to inter-relate locations and scale of the fringe patterns at different levels of zoom. The calculated parameters are scale and translation in both directions; these parameters make it possible to locate the coordinates of the region that the measurement system is zoomed in on, related to the area with lower magnification and relative locations of images within the same level of zoom. Results show that this technique is capable of finding the scale and shift parameters within the resolution of one pixel and therefore can restore continuity between images at different levels of zoom.

  1. Analysis of the Localization of Michelson Interferometer Fringes Using Fourier Optics and Temporal Coherence

    ERIC Educational Resources Information Center

    Narayanamurthy, C. S.

    2009-01-01

    Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in "Principles of Optics" by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer…

  2. 29 CFR 4.162 - Fringe benefits under contracts exceeding $2,500.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefits under contracts exceeding $2,500. 4.162... Compensation Standards § 4.162 Fringe benefits under contracts exceeding $2,500. (a) Pursuant to the statutory... contain a provision specifying the fringe benefits to be furnished the various classes of...

  3. 29 CFR 4.172 - Meeting requirements for particular fringe benefits-in general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... particular fringe benefits—in general. Where a fringe benefit determination specifies the amount of the... amount stated in the determination and the actual cost of the benefits which he provides. Unless... covered contract must be furnished the fringe benefits required by that determination for all hours...

  4. 29 CFR 4.165 - Wage payments and fringe benefits-in general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specifying higher monetary wages or fringe benefits than those contained in an applicable determination. However, if an applicable wage determination contains a wage or fringe benefit provision for a class of... 29 Labor 1 2010-07-01 2010-07-01 true Wage payments and fringe benefits-in general. 4.165...

  5. 29 CFR 4.50 - Types of wage and fringe benefit determinations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Types of wage and fringe benefit determinations. 4.50... Determination Procedures § 4.50 Types of wage and fringe benefit determinations. The Administrator specifies the... Agreement—(Successorship). Determinations that set forth the wage rates and fringe benefits,...

  6. 29 CFR 4.54 - Locality basis of wage and fringe benefit determinations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Locality basis of wage and fringe benefit determinations. 4... Wage Determination Procedures § 4.54 Locality basis of wage and fringe benefit determinations. (a... within which a wage or fringe benefit determination is applicable is, therefore, defined in each...

  7. The effect of surface-active solutes on water flow and contaminant transport in variably saturated porous media with capillary fringe effects.

    PubMed

    Henry, E J; Smith, J E

    2002-06-01

    Organic contaminants that decrease the surface tension of water (surfactants) can have an effect on unsaturated flow through porous media due to the dependence of capillary pressure on surface tension. We used an intermediate-scale 2D flow cell (2.44 x 1.53 x 0.108 m) packed with a fine silica sand to investigate surfactant-induced flow perturbations. Surfactant solution (7% 1-butanol and dye tracer) was applied at a constant rate at a point source located on the soil surface above an unconfined synthetic aquifer with ambient groundwater flow and a capillary fringe of approximately 55 cm. A glass plate allowed for visual flow and transport observations. Thirty instrumentation stations consist of time domain reflectometry probes and tensiometers measured in-situ moisture content and pressure head, respectively. As surfactant solution was applied at the point source, a transient flow perturbation associated with the advance of the surfactant solution was observed. Above the top of the capillary fringe the advance of the surfactant solution caused a visible drainage front that radiated from the point source. Upon reaching the capillary fringe, the drainage front caused a localized depression of the capillary fringe below the point source because the air-entry pressure decreased in proportion to the decrease in surface tension caused by the surfactant. Eventually, a new capillary fringe height was established. The height of the depressed capillary fringe was proportional to height of the initial capillary fringe multiplied by the relative surface tension of the surfactant solution. The horizontal transport of surfactant in the depressed capillary fringe, driven primarily by the ambient groundwater flow, caused the propagation of a wedge-shaped drying front in the downgradient direction. Comparison of dye transport during the surfactant experiment to dye transport in an experiment without surfactant indicated that because surfactant-induced drainage decreased the

  8. Ocular dispersion

    NASA Astrophysics Data System (ADS)

    Hammer, Daniel X.; Noojin, Gary D.; Thomas, Robert J.; Stolarski, David J.; Rockwell, Benjamin A.; Welch, Ashley J.

    1999-06-01

    Spectrally resolved white-light interferometry (SRWLI) was used to measure the wavelength dependence of refractive index (i.e., dispersion) for various ocular components. The accuracy of the technique was assessed by measurement of fused silica and water, the refractive indices of which have been measured at several different wavelengths. The dispersion of bovine and rabbit aqueous and vitreous humor was measured from 400 to 1100 nm. Also, the dispersion was measured from 400 to 700 nm for aqueous and vitreous humor extracted from goat and rhesus monkey eyes. For the humors, the dispersion did not deviate significantly from water. In an additional experiment, the dispersion of aqueous and vitreous humor that had aged up to a month was compared to freshly harvested material. No difference was found between the fresh and aged media. An unsuccessful attempt was also made to use the technique for dispersion measurement of bovine cornea and lens. Future refinement may allow measurement of the dispersion of cornea and lens across the entire visible and near-infrared wavelength band. The principles of white- light interferometry including image analysis, measurement accuracy, and limitations of the technique, are discussed. In addition, alternate techniques and previous measurements of ocular dispersion are reviewed.

  9. Robust determination of optical path difference: fringe tracking at the infrared optical telescope array interferometer.

    PubMed

    Pedretti, Ettore; Traub, Wesley A; Monnier, John D; Millan-Gabet, Rafael; Carleton, Nathaniel P; Schloerb, F Peter; Brewer, Michael K; Berger, Jean-Philippe; Lacasse, Marc G; Ragland, Sam

    2005-09-01

    We describe the fringe-packet tracking system used to equalize the optical path lengths at the Infrared Optical Telescope Array interferometer. The measurement of closure phases requires obtaining fringes on three baselines simultaneously. This is accomplished by use of an algorithm based on double Fourier interferometry for obtaining the wavelength-dependent phase of the fringes and a group-delay tracking algorithm for determining the position of the fringe packet. A comparison of data acquired with and without the fringe-packet tracker shows a factor of approximately 3 reduction of the error in the closure-phase measurement. The fringe-packet tracker has been able so far to track fringes with signal-to-noise ratios as low as 1.8 for stars as faint as mH = 7.0.

  10. The MROI fringe tracker: closing the loop on ICoNN

    NASA Astrophysics Data System (ADS)

    McCracken, T. M.; Jurgenson, C. A.; Santoro, F.; Shtromberg, A. V.; Alvidrez, V.; Torres, N.; Dahl, C.; Farris, A.; Buscher, D. F.; Haniff, C. A.; Young, J. S.; Seneta, E. B.; Creech-Eakman, M. J.

    2012-07-01

    The characterization of ICoNN, the Magdalena Ridge Observatory Interferometer's fringe tracker, through labor­ tory simulations is presented. The performance limits of an interferometer are set by its ability to keep the optical path difference between combination partners minimized. This is the job of the fringe tracker. Understanding the behavior and limits of the fringe tracker in a controlled environment is key to maximize the science output. This is being done with laboratory simulations of on-sky fringe tracking, termed the closed-loop fringe experi­ ment. The closed-loop fringe experiment includes synthesizing a white light source and atmospheric piston with estimation of the tracking error being fed back to mock delay lines in real-time. We report here on the progress of the closed-loop fringe experiment detailing its design, layout, controls and software.

  11. Time-average TV holography for vibration fringe analysis

    SciTech Connect

    Kumar, Upputuri Paul; Kalyani, Yanam; Mohan, Nandigana Krishna; Kothiyal, Mahendra Prasad

    2009-06-01

    Time-average TV holography is widely used method for vibration measurement. The method generates speckle correlation time-averaged J0 fringes that can be used for full-field qualitative visualization of mode shapes at resonant frequencies of an object under harmonic excitation. In order to map the amplitudes of vibration, quantitative evaluation of the time-averaged fringe pattern is desired. A quantitative evaluation procedure based on the phase-shifting technique used in two beam interferometry has also been adopted for this application with some modification. The existing procedure requires a large number of frames to be recorded for implementation. We propose a procedure that will reduce the number of frames required for the analysis. The TV holographic system used and the experimental results obtained with it on an edge-clamped, sinusoidally excited square aluminium plate sample are discussed.

  12. Further Developments of the Fringe-Imaging Skin Friction Technique

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory C.

    1996-01-01

    Various aspects and extensions of the Fringe-Imaging Skin Friction technique (FISF) have been explored through the use of several benchtop experiments and modeling. The technique has been extended to handle three-dimensional flow fields with mild shear gradients. The optical and imaging system has been refined and a PC-based application has been written that has made it possible to obtain high resolution skin friction field measurements in a reasonable period of time. The improved method was tested on a wingtip and compared with Navier-Stokes computations. Additionally, a general approach to interferogram-fringe spacing analysis has been developed that should have applications in other areas of interferometry. A detailed error analysis of the FISF technique is also included.

  13. A quantum radar detection protocol for fringe visibility enhancement

    NASA Astrophysics Data System (ADS)

    Koltenbah, Benjamin; Parazzoli, Claudio; Capron, Barbara

    2016-05-01

    We present analysis of a radar detection technique using a Photon Addition Homodyne Receiver (PAHR) that improves SNR of the interferometer fringes and reduces uncertainty of the phase measurement. This system uses the concept of Photon Addition (PA) in which the coherent photon distribution is altered. We discuss this process first as a purely mathematical concept to introduce PA and illustrate its effect on coherent photon distribution. We then present a notional proof-of-concept experiment involving a parametric down converter (PDC) and probabilistic post-selection of the results. We end with presentation of a more deterministic PAHR concept that is more suitable for development into a working system. Coherent light illuminates a target and the return signal interferes with the local oscillator reference photons to create the desired fringes. The PAHR alters the photon probability distribution of the returned light via interaction between the return photons and atoms. We refer to this technique as "Atom Interaction" or AI. The returning photons are focused at the properly prepared atomic system. The injected atoms into this region are prepared in the desired quantum state. During the interaction time, the initial quantum state evolves in such a way that the photon distribution function changes resulting in higher photon count, lower phase noise and an increase in fringe SNR. The result is a 3-5X increase of fringe SNR. This method is best suited for low light intensity (low photon count, 0.1-5) applications. The detection protocol could extend the range of existing systems without loss of accuracy, or conversely enhance a system's accuracy for given range. We present quantum mathematical analysis of the method to illustrate how both range and angular resolution improve in comparison with standard measurement techniques. We also suggest an experimental path to validate the method which also will lead toward deployment in the field.

  14. Iterated unscented Kalman filter for phase unwrapping of interferometric fringes.

    PubMed

    Xie, Xianming

    2016-08-22

    A fresh phase unwrapping algorithm based on iterated unscented Kalman filter is proposed to estimate unambiguous unwrapped phase of interferometric fringes. This method is the result of combining an iterated unscented Kalman filter with a robust phase gradient estimator based on amended matrix pencil model, and an efficient quality-guided strategy based on heap sort. The iterated unscented Kalman filter that is one of the most robust methods under the Bayesian theorem frame in non-linear signal processing so far, is applied to perform simultaneously noise suppression and phase unwrapping of interferometric fringes for the first time, which can simplify the complexity and the difficulty of pre-filtering procedure followed by phase unwrapping procedure, and even can remove the pre-filtering procedure. The robust phase gradient estimator is used to efficiently and accurately obtain phase gradient information from interferometric fringes, which is needed for the iterated unscented Kalman filtering phase unwrapping model. The efficient quality-guided strategy is able to ensure that the proposed method fast unwraps wrapped pixels along the path from the high-quality area to the low-quality area of wrapped phase images, which can greatly improve the efficiency of phase unwrapping. Results obtained from synthetic data and real data show that the proposed method can obtain better solutions with an acceptable time consumption, with respect to some of the most used algorithms.

  15. Analysis of localized fringes in the holographic optical Schlieren system

    NASA Technical Reports Server (NTRS)

    Kurtz, R. L.

    1980-01-01

    The relation between localization of interference fringes in classical and holographic interferometry is reviewed and an application of holographic interferometry is considered for which the object is a transparent medium with nonhomogeneous refractive index. The technique is based on the analysis of the optical path length change of the object wave as it propagates through a transparent medium. Phase shifts due to variations of the speed of light within the medium give rise to an interference pattern. The resulting interferogram can be used to determine the physical properties of the medium or transparent object. Such properties include the mass density of fluids, electron densities of plasmas, the temperature of fluids, the chemical species concentration of fluids, and the state of stress in solids. The optical wave used can be either a simple plane or spherical wave, or it may be a complicated spatial wave scattered by a diffusing screen. The mathematical theory on the formation and analysis of localized fringes, the general theoretical concepts used, and a computer code for analysis are included along with the inversion of fringe order data.

  16. Fiber-optic projected-fringe digital interferometry

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Beheim, Glenn

    1990-01-01

    A phase-stepped projected-fringe interferometer was developed which uses a closed-loop fiber-optic phase-control system to make very accurate surface profile measurements. The closed-loop phase-control system greatly reduces phase-stepping error, which is frequently the dominant source of error in digital interferometers. Two beams emitted from a fiber-optic coupler are combined to form an interference fringe pattern on a diffusely reflecting object. Reflections off of the fibers' output faces are used to create a phase-indicating signal for the closed-loop optical phase controller. The controller steps the phase difference between the two beams by pi/2 radians in order to determine the object's surface profile using a solid-state camera and a computer. The system combines the ease of alignment and automated data reduction of phase-stepping projected-fringe interferometry with the greatly improved phase-stepping accuracy of our closed-loop phase-controller. The system is demonstrated by measuring the profile of a plate containing several convex surfaces whose heights range from 15 to 25 micron high.

  17. Fringe visibility of multimode laser light scattered through turbid water.

    PubMed

    Swanson, N L; Pham, C N; VanWinkle, D H

    1997-12-20

    Several years ago Swanson [Proc. SPIE 1750, 397 (1992)] performed a simple Michelson interferometric determination of the coherence length of a multimode argon-ion laser after the light passed through a tank of water. As colloidal particles were added to the water the observed coherence length (as measured by twice the distance the mirror moved for fringes to disappear) decreased. Subsequently, a series of careful experiments were performed with a single-mode laser to more accurately measure this change. In these experiments it was found that the 1.5-MHz width of the 514.5-nm line of a single-mode argon-ion laser broadened by as much as 1.3 +/- 0.2 MHz when small colloidal particles were added. At first glance such a broadening should not have resulted in any discernible change in the original Michelson experiment because the gain curve for the multimode laser is of the order of a few gigahertz. The zeros in the fringe visibility function depend on the spectral characteristics of the modes. Upon scattering, the spectral characteristics of the individual laser modes change from Voigt functions, containing both Lorentzian and Gaussian components, to primarily Gaussian. It is this change in the statistical properties of the modes, not the broadening, that accounts for the change in the fringe visibility for a multimode source.

  18. Colloidal Crystal Growth Monitored By Bragg Diffraction Interference Fringes

    PubMed Central

    Bohn, Justin J.; Tikhonov, Alexander; Asher, Sanford A.

    2010-01-01

    We monitor the crystal growth kinetics of crystallization of a shear melted crystalline colloidal array (CCA). The fcc CCA heterogeneously nucleates at the flow cell wall surface. We examined the evolution of the (111) Bragg diffraction peak, and, for the first time, quantitatively monitored growth by measuring the temporal evolution of the Bragg diffraction interference fringes. Modeling of the evolution of the fringe patterns exposes the time dependence of the increasing crystal thickness. The initial diffusion driven linear growth is followed by ripening-driven growth. Between 80 to 90 μM NaCl concentrations the fcc crystals first linearly grow at rates between 1.9 and 4.2 μm/sec until they contact homogeneously nucleated crystals in the bulk. At lower salt concentrations interference fringes are not visible because the strong electrostatic interactions between particles result in high activation barriers, preventing defect annealing and leading to a lower crystal quality. The fcc crystals melt to a liquid phase at >90 μM NaCl concentrations. Increasing NaCl concentrations slows the fcc CCA growth rate consistent with the expectation of the classical Wilson-Frenkel growth theory. The final thickness of wall nucleated CCA is determined by the competition between growth of heterogeneously and homogenously nucleated CCA and increases with higher NaCl concentrations. PMID:20542277

  19. Fringe—A Java-based finite fringe analysis package

    NASA Astrophysics Data System (ADS)

    McIntyre, Timothy J.; Bishop, Alexis I.

    2012-09-01

    A package for analysing two-dimensional finite fringe interferograms is described. Through a combination of automatic and interactive routines, an interferogram can be processed to extract the phase shift imparted on the recording light by a transparent object. The package consists of routines to condition and pad the original image for Fourier transform analysis, to filter the image and obtain the phase, to unwrap the phase, and to remove the background phase ramp. A sample image recorded using holographic interferometry is successfully analysed. Program summary Program title: FRINGE Catalogue identifier: AEMM_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 134006 No. of bytes in distributed program, including test data, etc.: 4029801 Distribution format: tar.gz Programming language: Java. Computer: Personal Computers. Operating system: Mac OS X, Windows XP, Linux and any other system that can run Java Jar files. RAM: 1GB recommended Classification: 18. Nature of problem: A standalone multi-platform program to perform analysis of finite fringe interferograms. Solution method: Fourier filtering approach with phase unwrapping and background subtraction. Restrictions: Designed to analyse square images. Running time: Interactive processing takes several minutes. Minimal cpu time.

  20. SFFT based phase demodulation for faster interference fringes analysis

    NASA Astrophysics Data System (ADS)

    Lee, Chen-Yu; Hsu, Kuan-Yu; Lee, Chih-Kung

    2016-03-01

    Try to take advantages of the high-resolution CCD/CMOS developed over the years for real-time three-dimensional deformation/geometry metrology system development, Fourier transform (FT) based algorithms have been integrated to convert interference fringes to wrapped phase maps and then to unwrapped phase maps. All of which led to easy implementation of the algorithms developed over the years to achieve extremely efficient FT computation. Sparse Fast Fourier Transform (SFFT) that only calculating the non-zero coefficient in frequency domain, includes calculations of imaginary part and log, was implemented to further accelerate the computation rate for the above-mentioned FT based operations. Coupling the SFFT accelerated phase map computation approach with Michelson interferometer and Electronic Speckle Pattern Interferometry (ESPI) for near real-time three-dimensional deformation measurement led to the newly developed system. The directions of object deformation are revealed by performing FT to the interference fringes obtained with pre-introduced spatial carrier frequency, which provides a way to retrieve the phase maps by using a single rather than several intensity maps. With only one image frame needed, the interference fringes caused by the deformation could be recorded for off-line phase maps computation if the computation efforts are longer than the recording frame rate. To apply the SFFT algorithm on phase retrieval, a conceptual framework was presented. The benefit of using SFFT as compared to FT was also demonstrated.

  1. Physicochemical characterization and aerosol dispersion performance of organic solution advanced spray-dried microparticulate/nanoparticulate antibiotic dry powders of tobramycin and azithromycin for pulmonary inhalation aerosol delivery.

    PubMed

    Li, Xiaojian; Vogt, Frederick G; Hayes, Don; Mansour, Heidi M

    2014-02-14

    The purpose of this study was to systematically design pure antibiotic drug dry powder inhalers (DPIs) for targeted antibiotic pulmonary delivery in the treatment of pulmonary infections and comprehensively correlate the physicochemical properties in the solid-state and spray-drying conditions effects on aerosol dispersion performance as dry powder inhalers (DPIs). The two rationally chosen model antibiotic drugs, tobramycin (TOB) and azithromycin (AZI), represent two different antibiotic drug classes of aminoglycosides and macrolides, respectively. The particle size distributions were narrow, unimodal, and in the microparticulate/nanoparticulate size range. The SD particles possessed relatively spherical particle morphology, smooth surface morphology, low residual water content, and the absence of long-range molecular order. The emitted dose (ED%), fine particle fraction (FPF%) and respirable fraction (RF%) were all excellent. The MMAD values were in the inhalable range (<10 μm) with smaller MMAD values for SD AZI powders in contrast to SD TOB powders. Positive linear correlations were observed between the aerosol dispersion performance parameter of FPF with increasing spray-drying pump rates and also with the difference between thermal parameters expressed as Tg-To (i.e. the difference between the glass transition temperature and outlet temperature) for SD AZI powders. The aerosol dispersion performance for SD TOB appeared to be influenced by its high water vapor sorption behavior (hygroscopicity) and pump rates or To. Aerosol dispersion performance of SD powders were distinct for both antibiotic drug aerosol systems and also between different pump rates for each system.

  2. Fringe Benefits for Superintendents in Public Schools, 1983-84. Part 1 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    The fifth biennial National Survey of Fringe Benefits in Public Schools focuses on a wide range of fringe benefit practices offered all professional personnel. Data were collected from a national panel sample stratified by enrollment size; they are reported separately for large, medium, small, and very small systems, for five levels of per pupil…

  3. Fringe Benefits for Teachers in Public Schools, 1985-86. Part 3 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    The sixth biennial National Survey of Fringe Benefits in Public Schools describes a wide range of fringe benefit practices offered all professional personnel, including leave policies, insurance, retirement provisions, and tuition reimbursements. Data were collected from a national panel sample stratified by enrollment size and are reported…

  4. Fringe Benefits for Teachers in Public Schools, 1983-84. Part 3 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    The fifth biennial National Survey of Fringe Benefits in Public Schools focuses on a wide range of fringe benefit practices offered all professional personnel. Data were collected from a national panel sample stratified by enrollment size; they are reported separately for large, medium, small, and very small systems, for five levels of per pupil…

  5. Fringe Benefits for Administrators in Public Schools, 1985-86. Part 2 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    The sixth biennial National Survey of Fringe Benefits in Public Schools focuses on a wide range of fringe benefit practices offered all professional personnel, including leave policies, insurance coverage, tuition reimbursements, and expense account allowances. Data were collected from a national panel sample stratified by enrollment size and are…

  6. Fringe Benefits for Superintendents in Public Schools, 1985-86. Part 1 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    The sixth biennial National Survey of Fringe Benefits in Public Schools focuses on a wide range of fringe benefit practices offered all professional personnel. Data were collected from a national panel sample stratified by enrollment size and are reported separately for large, medium, small, and very small systems for five levels of per pupil…

  7. Fringe Benefits for Administrators in Public Schools, 1983-84. Part 2 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    The fifth biennial National Survey of Fringe Benefits in Public Schools focuses on a wide range of fringe benefit practices offered all professional personnel. Data were collected from a national panel sample stratified by enrollment size; they are reported separately for large, medium, small, and very small systems, for five levels of per pupil…

  8. Fringe pattern demodulation with a two-dimensional digital phase-locked loop algorithm.

    PubMed

    Gdeisat, Munther A; Burton, David R; Lalor, Michael J

    2002-09-10

    A novel technique called a two-dimensional digital phase-locked loop (DPLL) for fringe pattern demodulation is presented. This algorithm is more suitable for demodulation of fringe patterns with varying phase in two directions than the existing DPLL techniques that assume that the phase of the fringe patterns varies only in one direction. The two-dimensional DPLL technique assumes that the phase of a fringe pattern is continuous in both directions and takes advantage of the phase continuity; consequently, the algorithm has better noise performance than the existing DPLL schemes. The two-dimensional DPLL algorithm is also suitable for demodulation of fringe patterns with low sampling rates, and it outperforms the Fourier fringe analysis technique in this aspect.

  9. 29 CFR 5.22 - Effect of the Davis-Bacon fringe benefits provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 1 2013-07-01 2013-07-01 false Effect of the Davis-Bacon fringe benefits provisions. 5.22... Fringe Benefits Provisions of the Davis-Bacon Act § 5.22 Effect of the Davis-Bacon fringe benefits provisions. The Davis-Bacon Act and the prevailing wage provisions of the related statutes listed in § 1.1...

  10. 29 CFR 5.22 - Effect of the Davis-Bacon fringe benefits provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Effect of the Davis-Bacon fringe benefits provisions. 5.22... Fringe Benefits Provisions of the Davis-Bacon Act § 5.22 Effect of the Davis-Bacon fringe benefits provisions. The Davis-Bacon Act and the prevailing wage provisions of the related statutes listed in § 1.1...

  11. 29 CFR 5.22 - Effect of the Davis-Bacon fringe benefits provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Effect of the Davis-Bacon fringe benefits provisions. 5.22... Fringe Benefits Provisions of the Davis-Bacon Act § 5.22 Effect of the Davis-Bacon fringe benefits provisions. The Davis-Bacon Act and the prevailing wage provisions of the related statutes listed in § 1.1...

  12. 29 CFR 5.22 - Effect of the Davis-Bacon fringe benefits provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 1 2011-07-01 2011-07-01 false Effect of the Davis-Bacon fringe benefits provisions. 5.22... Fringe Benefits Provisions of the Davis-Bacon Act § 5.22 Effect of the Davis-Bacon fringe benefits provisions. The Davis-Bacon Act and the prevailing wage provisions of the related statutes listed in § 1.1...

  13. 29 CFR 5.22 - Effect of the Davis-Bacon fringe benefits provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 1 2012-07-01 2012-07-01 false Effect of the Davis-Bacon fringe benefits provisions. 5.22... Fringe Benefits Provisions of the Davis-Bacon Act § 5.22 Effect of the Davis-Bacon fringe benefits provisions. The Davis-Bacon Act and the prevailing wage provisions of the related statutes listed in § 1.1...

  14. Parameter estimation of optical fringes with quadratic phase using the fractional Fourier transform

    NASA Astrophysics Data System (ADS)

    Lu, Ming-Feng; Zhang, Feng; Tao, Ran; Ni, Guo-Qiang; Bai, Ting-Zhu; Yang, Wen-Ming

    2015-11-01

    Optical fringes with a quadratic phase are often encountered in optical metrology. Parameter estimation of such fringes plays an important role in interferometric measurements. A novel method is proposed for accurate and direct parameter estimation using the fractional Fourier transform (FRFT), even in the presence of noise and obstacles. We take Newton's rings fringe patterns and electronic speckle pattern interferometry (ESPI) interferograms as classic examples of optical fringes that have a quadratic phase and present simulation and experimental results demonstrating the performance of the proposed method.

  15. Formation of circular fringes by interference of two boundary diffraction waves using holography.

    PubMed

    Kumar, Raj; Chhachhia, D P

    2013-08-01

    The theory of boundary diffraction waves (BDWs) is gaining importance due to its simplicity and physically appealing nature. The present work reports formation of circular fringes far away from the geometrically illuminated region by interference of two BDWs. One BDW is reconstructed from the hologram while the second is coming directly from the knife-edge. The uniqueness of the fringes is that their position can be controlled on the screen at will and fringes can be produced with bright as well as dark central fringe. These results could play an important role in understanding the nature of diffraction of light.

  16. Phase recovery from a single fringe pattern using an orientational vector-field-regularized estimator.

    PubMed

    Villa, Jesús; De la Rosa, Ismael; Miramontes, Gerardo; Quiroga, Juan Antonio

    2005-12-01

    Recent studies have demonstrated that the phase recovery from a single fringe pattern with closed fringes can be properly performed if the modulo 2pi fringe orientation is estimated. For example, the fringe pattern in quadrature can be efficiently obtained in terms of the orientational phase spatial operator using fast Fourier transformations and a spiral phase spectral operator in the Fourier space. The computation of the modulo 2pi fringe orientation, however, is by far the most difficult task in the global process of phase recovery. For this reason we propose the demodulation of fringe patterns with closed fringes through the computation of the modulo 2pi fringe orientation using an orientational vector-field-regularized estimator. As we will show, the phase recovery from a single pattern can be performed in an efficient manner using this estimator, provided that it requires one to solve locally in the fringe pattern a simple linear system to optimize a regularized cost function. We present simulated and real experiments applying the proposed methodology.

  17. Soot Nanostructure: Using Fringe Analysis Software on High Resolution Transmission Electron Microscopy of Carbon Soot

    NASA Technical Reports Server (NTRS)

    King, James D.

    2004-01-01

    Using high resolution transmission electron images of carbon nanotubes and carbon particles, we are able to use image analysis program to determine several carbon fringe properties, including length, separation, curvature and orientation. Results are shown in the form of histograms for each of those quantities. The combination of those measurements can give a better indication of the graphic structure within nanotubes and particles of carbon and can distinguish carbons based upon fringe properties. Carbon with longer, straighter and closer spaced fringes are considered graphite, while amorphous carbon contain shorter, less structured fringes.

  18. lunatic fringe is an essential mediator of somite segmentation and patterning.

    PubMed

    Evrard, Y A; Lun, Y; Aulehla, A; Gan, L; Johnson, R L

    1998-07-23

    The gene lunatic fringe encodes a secreted factor with significant sequence similarity to the Drosophila gene fringe. fringe has been proposed to function as a boundary-specific signalling molecule in the wing imaginal disc, where it is required to localize signalling activity by the protein Notch to the presumptive wing margin. By targeted disruption in mouse embryos, we show here that lunatic fringe is likewise required for boundary formation. lunatic fringe mutants fail to form boundaries between individual somites, the initial segmental unit of the vertebrate trunk. In addition, the normal alternating rostral-caudal pattern of the somitic mesoderm is disrupted, suggesting that intersomitic boundary formation and rostral-caudal patterning of somites are mechanistically linked by a process that requires lunatic fringe activity. As a result, the derivatives of the somitic mesoderm, especially the axial skeleton, are severely disorganized in lunatic fringe mutants. Taken together, our results demonstrate an essential function for a vertebrate fringe homologue and suggest a model in which lunatic fringe modulates Notch signalling in the segmental plate to regulate somitogenesis and rostral-caudal patterning of somites simultaneously.

  19. Young's interference fringes with narrow-band light.

    PubMed

    Wolf, E

    1983-05-01

    The changes in the interference pattern in Young's interference experiment, produced by placing two identical narrow-band filters in front of the pinholes, are analyzed. It is shown theoretically that, in general, the fringes will not become sharp (i.e., their maximum visibility will not tend to unity) even when the filters have arbitrarily narrow passbands. The analysis brings out a relationship between the complex degree of coherence in the space-time and the space-frequency domains. When the passbands of the filters are narrow enough, the filtered light is found to be cross-spectrally pure.

  20. Mark 3 real-time fringe detection system

    NASA Technical Reports Server (NTRS)

    Levine, J. I.; Whitney, A. R.

    1980-01-01

    A RAM memory built into the Mark 3 decoder module allows the capture of 1 Megabit of data. Data may be collected either in real time or from a pre-recorded tape. Once collected, the data may be retrieved using a standard EIA serial data link. The data may be transmitted to a remote computer for cross correlation processing with similar data from other stations to verify fringes in real time. The data may also be analyzed by a local computer to verify phase calibration, bandpass, format, etc., during a Mark 3 observing session.

  1. Intertidal stromatolites in a fringing Holocene reef complex, Bahamas

    NASA Astrophysics Data System (ADS)

    Reid, R. Pamela; Browne, Kathleen M.

    1991-01-01

    Intertidal stromatolites are major components of a fringing Holocene reef complex at Stocking Island, Exuma Cays, Bahamas. Trapping and binding of fine-grained carbonate sand by microorganisms, primarily filamentous cyanobacteria and diatoms, and differential lithification of sediment have produced layered structures with up to 0.5 m of relief. Formation of these stromatolites in an environment of normal marine salinity is attributed to reduced competition from crustose red algae, availability of a stable substrate, and rapid cementation. Destruction of lamination in Stocking Island stromatolites by molluscs, sponges, and worms suggests that boring invertebrates play a key role in stromatolite preservation.

  2. Effects of fringing reefs on tsunami inundation: American Samoa

    NASA Astrophysics Data System (ADS)

    Gelfenbaum, Guy; Apotsos, Alex; Stevens, Andrew W.; Jaffe, Bruce

    2011-07-01

    A numerical model of tsunami inundation, Delft3D, which has been validated for the 29 September 2009 tsunami in Tutuila, American Samoa, is used to better understand the impact of fringing coral reefs and embayments on tsunami wave heights, inundation distances, and velocities. The inundation model is used to explore the general conditions under which fringing reefs act as coastal buffers against incoming tsunamis. Of particular interest is the response of tsunamis to reefs of varying widths, depths, and roughness, as well as the effects of channels incised in the reef and the focusing effect of embayments. Model simulations for conditions similar to Tutuila, yet simplified to be uniform in the alongshore, suggest that for narrow reefs, less than about 200 m wide, the shoaling owing to shallow water depths over the fringing reef dominates, inducing greater wave heights onshore under some conditions and farther inundation inland. As the reef width increases, wave dissipation through bottom friction begins to dominate and the reef causes the tsunami wave heights to decrease and the tsunami to inundate less far inland. A sensitivity analysis suggests that coral reef roughness is important in determining the manner in which a fringing reef affects tsunami inundation. Smooth reefs are more likely to increase the onshore velocity within the tsunami compared to rough reefs. A larger velocity will likely result in an increased impact of the tsunami on structures and buildings. Simulations developed to explore 2D coastal morphology show that incised channels similar to those found around Tutuila, as well as coastal embayments, also affect tsunami inundation, allowing larger waves to penetrate farther inland. The largest effect is found for channels located within embayments, and for embayments that narrow landward. These simulations suggest that embayments that narrow landward, such as Fagafue Bay on the north side of Tutuila, and that have an incised deep channel, can

  3. Effects of fringing reefs on tsunami inundation: American Samoa

    USGS Publications Warehouse

    Gelfenbaum, G.; Apotsos, A.; Stevens, A.W.; Jaffe, B.

    2011-01-01

    A numerical model of tsunami inundation, Delft3D, which has been validated for the 29 September 2009 tsunami in Tutuila, American Samoa, is used to better understand the impact of fringing coral reefs and embayments on tsunami wave heights, inundation distances, and velocities. The inundation model is used to explore the general conditions under which fringing reefs act as coastal buffers against incoming tsunamis. Of particular interest is the response of tsunamis to reefs of varying widths, depths, and roughness, as well as the effects of channels incised in the reef and the focusing effect of embayments. Model simulations for conditions similar to Tutuila, yet simplified to be uniform in the alongshore, suggest that for narrow reefs, less than about 200 m wide, the shoaling owing to shallow water depths over the fringing reef dominates, inducing greater wave heights onshore under some conditions and farther inundation inland. As the reef width increases, wave dissipation through bottom friction begins to dominate and the reef causes the tsunami wave heights to decrease and the tsunami to inundate less far inland. A sensitivity analysis suggests that coral reef roughness is important in determining the manner in which a fringing reef affects tsunami inundation. Smooth reefs are more likely to increase the onshore velocity within the tsunami compared to rough reefs. A larger velocity will likely result in an increased impact of the tsunami on structures and buildings. Simulations developed to explore 2D coastal morphology show that incised channels similar to those found around Tutuila, as well as coastal embayments, also affect tsunami inundation, allowing larger waves to penetrate farther inland. The largest effect is found for channels located within embayments, and for embayments that narrow landward. These simulations suggest that embayments that narrow landward, such as Fagafue Bay on the north side of Tutuila, and that have an incised deep channel, can

  4. Digital Fringe Counting for Intrinsic Fabry-Perot Interferometers

    NASA Technical Reports Server (NTRS)

    Froggatt, Mark; Melvin, Leland

    1996-01-01

    A digital dual-wavelength method of demodulating long (17cm) Intrinsic Fabry-Perot Interferometers (IFPI) is presented. The method builds upon previous techniques using small shifts in the lasing wavelength of a laser diode induced by changes in the driving current. The intensity of the light reflected from the IFPI is sampled at two carefully selected values of laser diode drive current. Digital logic is then used to count fringes based upon these two sampled values. Experimental verification of the method is described.

  5. Regularization methods for processing fringe-pattern images.

    PubMed

    Marroquin, J L; Rivera, M; Botello, S; Rodriguez-Vera, R; Servin, M

    1999-02-10

    A powerful technique for processing fringe-pattern images is based on Bayesian estimation theory with prior Markov random-field models. In this approach the solution of a processing problem is characterized as the minimizer of a cost function with terms that specify that the solution should be compatible with the available observations and terms that impose certain (prior) constraints on the solution. We show that, by the appropriate choice of these terms, one can use this approach in almost every processing step for accurate and robust interferogram demodulation and phase unwrapping.

  6. Three-dimensional scanner based on fringe projection

    NASA Astrophysics Data System (ADS)

    Nouri, Taoufik

    1995-07-01

    This article presents a way of scanning 3D objects using noninvasive and contact loss techniques. The principle is to project parallel fringes on an object and then to record the object at two viewing angles. With an appropriate treatment one can reconstruct the 3D object even when it has no symmetry planes. The 3D surface data are available immediately in digital form for computer visualization and for analysis software tools. The optical setup for recording the object, the data extraction and treatment, and the reconstruction of the object are reported and commented on. Application is proposed for reconstructive/cosmetic surgery, CAD, animation, and research.

  7. Multiple rotation assessment through isothetic fringes in speckle photography

    SciTech Connect

    Angel, Luciano; Tebaldi, Myrian; Bolognini, Nestor

    2007-05-10

    The use of different pupils for storing each speckled image in speckle photography is employed to determine multiple in-plane rotations. The method consists of recording a four-exposure specklegram where the rotations are done between exposures. This specklegram is then optically processed in a whole field approach rendering isothetic fringes, which give detailed information about the multiple rotations. It is experimentally demonstrated that the proposed arrangement permits the depiction of six isothetics in order to measure either six different angles or three nonparallel components for two local general in-plane displacements.

  8. The Carlina-type diluted telescope. Stellar fringes on Deneb

    NASA Astrophysics Data System (ADS)

    Le Coroller, H.; Dejonghe, J.; Hespeels, F.; Arnold, L.; Andersen, T.; Deram, P.; Ricci, D.; Berio, P.; Blazit, A.; Clausse, J.-M.; Guillaume, C.; Meunier, J. P.; Regal, X.; Sottile, R.

    2015-01-01

    Context. The performance of interferometers has been much increased over the past ten years. But the number of observable objects is still limited by the low sensitivity and imaging capability of the current facilities. Studies have been conducted with the aim to propose a new generation of interferometers. Aims: The Carlina concept studied at the Haute-Provence Observatory consists of an optical interferometer configured as a diluted version of the Arecibo radio telescope: above the diluted primary mirror made of fixed co-spherical segments, a helium balloon or cables that are suspended between two mountains and/or pylons carry a gondola containing the focal optics. This concept does not require delay lines. Methods: Since 2003, we have been building a technical demonstrator of this diluted telescope. The main goals of this project were to find opto-mechanical solutions to stabilize the optics attached to cables at several tens of meters above the ground, and to characterize this diluted telescope under real conditions. In 2012, we obtained metrology fringes, and co-spherized the primary mirrors within one micron accuracy. In 2013, we tested the whole optical train: servo loop, metrology, and the focal gondola. Results: We obtained stellar fringes on Deneb in September 2013. We here present the characteristics of these observations: quality of the guiding, signal-to-noise ratio reached, and possible improvements for a future system. Conclusions: By detecting fringes on Deneb, we confirm that the entire system conceptually has worked correctly. It also proves that when the primary mirrors are aligned using the metrology system, we can directly record fringes in the focal gondola, even in blind operation. It is an important step that demonstrates the feasibility of building a diluted telescope using cables strained between cliffs or pylons. Carlina, like the Multiple Mirror Telescope (MMT) or Large Binocular Telescope (LBT), could be one of the first members of a

  9. Dispersion Modeling.

    ERIC Educational Resources Information Center

    Budiansky, Stephen

    1980-01-01

    This article discusses the need for more accurate and complete input data and field verification of the various models of air pollutant dispension. Consideration should be given to changing the form of air quality standards based on enhanced dispersion modeling techniques. (Author/RE)

  10. MATE (Materials for Advanced Turbine Engines) Program, Project 3. Volume 2: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner

    NASA Technical Reports Server (NTRS)

    Bose, S.; Sheffler, K. D.

    1988-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Two yttria (Y2O3) dispersion strengthened alloys were evaluated; Incoloy MA956 and Haynes Development Alloy (HDA) 8077 (NiCrAl base). Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. MA956 was selected as the final alloy based on manufacturing reproducibility for evaluation as a burner liner. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components and using a louvered configuration was designed and constructed. The louvered configuration was chosen because of field experience and compatibility with the bill of material PW2037 design. The simulated flight cycle for the ground based engine tests consisted of 4.5 min idle, 1.5 min takeoff and intermediate conditions in a PW2037 engine with average uncorrected combustor exit temperature of 1527 C. Post test evaluation consisting of visual observations and fluorescent penetrant inspections was conducted after 500 cycles of testing. No loss of integrity in the burner liner was shown.

  11. Externally Dispersed Interferometry for Precision Radial Velocimetry

    SciTech Connect

    Erskine, D J; Muterspaugh, M W; Edelstein, J; Lloyd, J; Herter, T; Feuerstein, W M; Muirhead, P; Wishnow, E

    2007-03-27

    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 spectral comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. The moire pattern shifts in phase in response to a Doppler shift. Moire patterns are broader than the underlying spectral features and more easily survive spectrograph blurring and common distortions. Thus, the EDI technique allows lower resolution spectrographs having relaxed optical tolerances (and therefore higher throughput) to return high precision velocity measurements, which otherwise would be imprecise for the spectrograph alone.

  12. Study and Removal of the Interference Fringes in Images Observed by the Imaging System of NVST

    NASA Astrophysics Data System (ADS)

    Wang, S. B.; Xu, Z.; Xiang, Y. Y.; Jin, Z. Y.

    2016-09-01

    The 1-meter New Vacuum Solar Telescope is a new generation ground-based solar observation facility of China, located at the FuXian-Lake Solar Observatory of Yunnan Observatories. One of its instrumentations is a five-channel high-resolution image system, while the Hα-channel is used as the traditional way for solar chromospheric observation. Using a pco.4000 CCD as the detector, we usually observe complicated fringes resulted from the thin-film interference in scientific data. These fringes can not be eliminated completely by flat-field calibration, and even be intensified after image reconstruction processes. From about 4-hour continuous Hα off-band observations, we study the temporal-variation of the fringe pattern and amplitude. We find that in contrast to the stable pattern, the fringe amplitude obviously changed with time. The visibility increases 9 times over 4 hours. We speculate that it is due to the temporal-variation of the incident light intensity and the direction with respect to the CCD position. Consequently, we suggest two methods to calibrate or eliminate the fringes. On one hand, we suggest to change the CCD inner-glass-window to a wedge-shape with a wedge-angle of about 2 degree in order to reduce the fringe-interval to a CCD pixel size. It is shown that this change can eliminate the majority of fringes. Only few fringes with the visibility of 0.6% can be found in 1/24 of field-of-view. On the other hand, we make efforts to eliminate the fringes by correcting the data using a so-called fringe-flat again after the normal data reduction (flat-field and dark-field modification). A fringe-flat is extracted from the data by using a Fourier filtering technique in frequency domain or a median-filter in space domain, and both produce a very similar result. We find that the corrected data using the fringe-flat produces a substantial reduction in the fringe amplitude with the visibility decreasing to about 1/8. However, we have to point out that there

  13. Directly Measuring the Degree of Quantum Coherence using Interference Fringes

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Tao; Tang, Jian-Shun; Wei, Zhi-Yuan; Yu, Shang; Ke, Zhi-Jin; Xu, Xiao-Ye; Li, Chuan-Feng; Guo, Guang-Can

    2017-01-01

    Quantum coherence is the most distinguished feature of quantum mechanics. It lies at the heart of the quantum-information technologies as the fundamental resource and is also related to other quantum resources, including entanglement. It plays a critical role in various fields, even in biology. Nevertheless, the rigorous and systematic resource-theoretic framework of coherence has just been developed recently, and several coherence measures are proposed. Experimentally, the usual method to measure coherence is to perform state tomography and use mathematical expressions. Here, we alternatively develop a method to measure coherence directly using its most essential behavior—the interference fringes. The ancilla states are mixed into the target state with various ratios, and the minimal ratio that makes the interference fringes of the "mixed state" vanish is taken as the quantity of coherence. We also use the witness observable to witness coherence, and the optimal witness constitutes another direct method to measure coherence. For comparison, we perform tomography and calculate l1 norm of coherence, which coincides with the results of the other two methods in our situation. Our methods are explicit and robust, providing a nice alternative to the tomographic technique.

  14. Vortex metrology using Fourier analysis techniques: vortex networks correlation fringes.

    PubMed

    Angel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, Néstor

    2012-10-20

    In this work, we introduce an alternative method of analysis in vortex metrology based on the application of the Fourier optics techniques. The first part of the procedure is conducted as is usual in vortex metrology for uniform in-plane displacement determination. On the basis of two recorded intensity speckled distributions, corresponding to two states of a diffuser coherently illuminated, we numerically generate an analytical signal from each recorded intensity pattern by using a version of the Riesz integral transform. Then, from each analytical signal, a two-dimensional pseudophase map is generated in which the vortices are located and characterized in terms of their topological charges and their core's structural properties. The second part of the procedure allows obtaining Young's interference fringes when Fourier transforming the light passing through a diffracting mask with multiple apertures at the locations of the homologous vortices. In fact, we use the Fourier transform as a mathematical operation to compute the far-field diffraction intensity pattern corresponding to the multiaperture set. Each aperture from the set is associated with a rectangular hole that coincides both in shape and size with a pixel from recorded images. We show that the fringe analysis can be conducted as in speckle photography in an extended range of displacement measurements. Effects related with speckled decorrelation are also considered. Our experimental results agree with those of speckle photography in the range in which both techniques are applicable.

  15. Sand composition and transport history on a fringing coral reef, Molokai, Hawaii

    USGS Publications Warehouse

    Calhoun, R.S.; Field, M.E.

    2008-01-01

    Composition of sand grains from the beaches, reef flat, and fore reef of south Molokai, Hawaii, provides key information about the origin and transport history of sediment on the reef and adjacent beach. The most common grain types include coralline algae, coral, chemically altered carbonate, and siliciclastic grains. Minor components include calcareous algal plates (Halimeda), mollusk fragments, and foraminifera; in selected areas, these components are abundant. Similarities in composition indicate that sand grains are freely transported between the beach and the reef-flat environments, whereas the fore reef has limited exchange of sand with either the beach or the reef flat. Overall, the calcium carbonate fraction of the sand, silt, and clay increases with distance offshore from 400 to 650 m, where the percentages plateau and remain relatively stable across the fore reef. The calcium carbonate content of bottom sediment indicates that sand transport on the reef flat is generally shore parallel with little shore-normal movement. This study has implications for management of beaches and coastal resources along fringing coral reefs in that it documents the effectiveness of the wide reef flat and reef crest in blocking sand transport with the fore reef. It also indicates that sediment introduced to the inner reef flat is not quickly dispersed seaward and therefore has a relatively high residence time in that setting.

  16. Continuous flow Overhauser dynamic nuclear polarization of water in the fringe field of a clinical magnetic resonance imaging system for authentic image contrast

    PubMed Central

    Lingwood, Mark D.; Siaw, Ting Ann; Sailasuta, Napapon; Ross, Brian D.; Bhattacharya, Pratip; Han, Songi

    2016-01-01

    We describe and demonstrate a system to generate hyperpolarized water in the 0.35 T fringe field of a clinical 1.5 T whole-body magnetic resonance imaging (MRI) magnet. Once generated, the hyperpolarized water is quickly and continuously transferred from the 0.35 T fringe to the 1.5 T center field of the same magnet for image acquisition using standard MRI equipment. The hyperpolarization is based on Overhauser dynamic nuclear polarization (DNP), which effectively and quickly transfers the higher spin polarization of free radicals to nuclear spins at ambient temperatures. We visualize the dispersion of hyperpolarized water as it flows through water-saturated systems by utilizing an observed −15 fold DNP signal enhancement with respect to the unenhanced 1H MRI signal of water at 1.5 T. The experimental DNP apparatus presented here is readily portable and can be brought to and used with any conventional unshielded MRI system. A new method of immobilizing radicals to gel beads via polyelectrolyte linker arms is described, which led to superior flow Overhauser DNP performance compared to previously presented gels. We discuss the general applicability of Overhauser DNP hyperpolarization of water and aqueous solutions in the fringe field of commercially available magnets with central fields up to 4.7 Tesla. PMID:20541445

  17. Fog dispersion

    NASA Technical Reports Server (NTRS)

    Frost, W.; Christensen, L. S.; Collins, F. G.; Camp, D. W.

    1980-01-01

    A study of economically viable techniques for dispersing warm fog at commercial airports is presented. Five fog dispersion techniques are examined: evaporation suppression, downwash, mixing, seeding with hygroscopic material, thermal techniques, and charged particle techniques. Thermal techniques, although effective, were found to be too expensive for routine airport operations, and detrimental to the environment. Seeding or helicopter downwash are practical for small-scale or temporary fog clearing, but are probably not useful for airport operations on a routine basis. Considerable disagreement exists on the capability of charged particle techniques, which stems from the fact that different assumptions and parameter values are used in the analytical models. Recommendations resulting from the review of this technique are listed, and include: experimental measurements of the parameters in question; a study to ascertain possible safety hazards, such as increased electrical activity or fuel ignition during refueling operations which could render charged particle techniques impractical; and a study of a single charged particle generator.

  18. The suppressed negative bias illumination-induced instability in In-Ga-Zn-O thin film transistors with fringe field structure

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chun; Chang, Ting-Chang; Li, Hung-Wei; Hsieh, Tien-Yu; Chen, Te-Chih; Wu, Chang-Pei; Chou, Cheng-Hsu; Chung, Wang-Cheng; Chang, Jung-Fang; Tai, Ya-Hsiang

    2012-11-01

    This study investigates the suppressed negative gate bias illumination stress (NBIS) -induced instability of via-type amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs) with fringe field (FF) structures. The less negative threshold voltage shifts of devices after NBIS are showed when device has larger FF structures. This finding is attributed to more dispersive distribution of photo-generated holes in the width direction of a-IGZO during NBIS, which reduce the hole trapping phenomenon in the front channel interface. The a-IGZO TFT with FF structure is expected to be an effective method to increase the electrical reliability of devices after NBIS.

  19. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...), the rate applicable to the computation of cash equivalents for vacation benefits is the hourly wage... 29 Labor 1 2010-07-01 2010-07-01 true Discharging fringe benefit obligations by equivalent means... CONTRACTS Compensation Standards Compliance with Compensation Standards § 4.177 Discharging fringe...

  20. 48 CFR 22.406-2 - Wages, fringe benefits, and overtime.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... irrevocably to a trustee or a third party under any bona fide plan or program to provide for medical or hospital care, pensions, compensation for injuries or illness resulting from occupational activity... fide fringe benefit. (3) Other contributions or anticipated costs for bona fide fringe benefits to...

  1. 48 CFR 22.406-2 - Wages, fringe benefits, and overtime.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... irrevocably to a trustee or a third party under any bona fide plan or program to provide for medical or hospital care, pensions, compensation for injuries or illness resulting from occupational activity... fide fringe benefit. (3) Other contributions or anticipated costs for bona fide fringe benefits to...

  2. 48 CFR 22.406-2 - Wages, fringe benefits, and overtime.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... irrevocably to a trustee or a third party under any bona fide plan or program to provide for medical or hospital care, pensions, compensation for injuries or illness resulting from occupational activity... fide fringe benefit. (3) Other contributions or anticipated costs for bona fide fringe benefits to...

  3. Theoretical analysis of interferometer wave front tilt and fringe radiant flux on a rectangular photodetector.

    PubMed

    Smith, Robert; Fuss, Franz Konstantin

    2013-09-06

    This paper is a theoretical analysis of mirror tilt in a Michelson interferometer and its effect on the radiant flux over the active area of a rectangular photodetector or image sensor pixel. It is relevant to sensor applications using homodyne interferometry where these opto-electronic devices are employed for partial fringe counting. Formulas are derived for radiant flux across the detector for variable location within the fringe pattern and with varying wave front angle. The results indicate that the flux is a damped sine function of the wave front angle, with a decay constant of the ratio of wavelength to detector width. The modulation amplitude of the dynamic fringe pattern reduces to zero at wave front angles that are an integer multiple of this ratio and the results show that the polarity of the radiant flux changes exclusively at these multiples. Varying tilt angle causes radiant flux oscillations under an envelope curve, the frequency of which is dependent on the location of the detector with the fringe pattern. It is also shown that a fringe count of zero can be obtained for specific photodetector locations and wave front angles where the combined effect of fringe contraction and fringe tilt can have equal and opposite effects. Fringe tilt as a result of a wave front angle of 0.05° can introduce a phase measurement difference of 16° between a photodetector/pixel located 20 mm and one located 100 mm from the optical origin.

  4. Comments on “A new method for phase extraction from a single fringe pattern”

    NASA Astrophysics Data System (ADS)

    Ferrari, José A.

    2007-02-01

    We comment on the recent paper by Tay et al. [Opt. Commun. 239 (2004) 251], in which a phase extraction method from a single fringe pattern is proposed. Their claimed "new method" is based on a couple of assumptions on the behavior of the fringe pattern, which are closely related to the well-known Fourier-transform technique.

  5. Fringe Benefits for Administrative and Supervisory Personnel in Public Schools, 1973-74. An ERS Report.

    ERIC Educational Resources Information Center

    Stieber, Gertrude N.

    This report, the second of two major studies for 1973-74 on salary schedules and fringe benefits for administrative and supervisory personnel in public schools, presents the results of a broad national study of fringe benefits for school administrators. It provides information on the extent and nature of leave provisions (sickness, vacation,…

  6. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 2 2011-04-01 2011-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means...

  7. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means...

  8. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means...

  9. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means...

  10. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means...

  11. 49 CFR 1242.85 - Fringe benefits (account 12-63-00).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Fringe benefits (account 12-63-00). 1242.85....85 Fringe benefits (account 12-63-00). Separate the common expenses in proportion to the total common salaries and wages expense separation (account 11-XX-XX) determined in §§ 1242.83 and 1242.84....

  12. 49 CFR 1242.85 - Fringe benefits (account 12-63-00).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-63-00). 1242.85....85 Fringe benefits (account 12-63-00). Separate the common expenses in proportion to the total common salaries and wages expense separation (account 11-XX-XX) determined in §§ 1242.83 and 1242.84....

  13. 49 CFR 1242.85 - Fringe benefits (account 12-63-00).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Fringe benefits (account 12-63-00). 1242.85....85 Fringe benefits (account 12-63-00). Separate the common expenses in proportion to the total common salaries and wages expense separation (account 11-XX-XX) determined in §§ 1242.83 and 1242.84....

  14. 49 CFR 1242.85 - Fringe benefits (account 12-63-00).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Fringe benefits (account 12-63-00). 1242.85....85 Fringe benefits (account 12-63-00). Separate the common expenses in proportion to the total common salaries and wages expense separation (account 11-XX-XX) determined in §§ 1242.83 and 1242.84....

  15. Ramsey fringes in a Bose-Einstein condensate between atoms and molecules.

    PubMed

    Kokkelmans, S J J M F; Holland, M J

    2002-10-28

    In a recent experiment, a Feshbach scattering resonance was exploited to observe Ramsey fringes in a 85Rb Bose-Einstein condensate. The oscillation frequency corresponded to the binding energy of the molecular state. We show that the observations are remarkably consistent with predictions of a resonance field theory in which the fringes arise from oscillations between atoms and molecules.

  16. 26 CFR 1.132-1 - Exclusion from gross income for certain fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... benefits. 1.132-1 Section 1.132-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY....132-1 Exclusion from gross income for certain fringe benefits. (a) In general. Gross income does not include any fringe benefit which qualifies as a— (1) No-additional-cost service, (2) Qualified...

  17. 26 CFR 1.132-5T - Working condition fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Working condition fringe-1985 through 1988....132-5T Working condition fringe—1985 through 1988 (temporary). (a) In general—(1) Definition. Gross income does not include the value of a working condition fringe. The term “working condition...

  18. Design, characterization, and aerosol dispersion performance modeling of advanced co-spray dried antibiotics with mannitol as respirable microparticles/nanoparticles for targeted pulmonary delivery as dry powder inhalers.

    PubMed

    Li, Xiaojian; Vogt, Frederick G; Hayes, Don; Mansour, Heidi M

    2014-09-01

    Dry powder inhalation aerosols of antibiotic drugs (a first-line aminoglycoside, tobramycin, and a first-line macrolide, azithromycin) and a sugar alcohol mucolytic agent (mannitol) as co-spray dried (co-SD) particles at various molar ratios of drug:mannitol were successfully produced by organic solution advanced co-spray drying from dilute solute concentration. These microparticulate/nanoparticulate aerosols consisting of various antibiotic drug:mannitol molar ratios were rationally designed with a narrow and unimodal primary particle size distribution, spherical particle shape, relatively smooth particle surface, and very low residual water content to minimize the interparticulate interactions and enhance in vitro aerosolization. These microparticulate/nanoparticulate inhalation powders were high-performing aerosols as reflected in the aerosol dispersion performance parameters of emitted dose, fine particle fraction (FPF), respirable fraction (RF), and mass median aerodynamic diameter (MMAD). The glass transition temperature (Tg) values were significantly above room temperature, which indicated that the co-SD powders were all in the amorphous glassy state. The Tg values for co-SD tobramycin:mannitol powders were significantly lower than those for co-SD azithromycin:mannitol powders. The interplay between aerosol dispersion performance parameters and Tg was modeled where higher Tg values (i.e., more ordered glass) were correlated with higher values in FPF and RF and lower values in MMAD.

  19. Regenerated phase-shifted sinusoids assisted EMD for adaptive analysis of fringe patterns

    NASA Astrophysics Data System (ADS)

    Wang, Chenxing; Kemao, Qian; Da, Feipeng

    2016-12-01

    Fringe patterns are often produced from optical metrology. It is important yet challenging to reduce noise and remove a complicated background in a fringe pattern, for which empirical mode decomposition based methods have been proven useful. However, the mode-mixing problem and the difficulty in automatic mode classification limit the application of these methods. In this paper, a newly developed method named regenerated phase-shifted sinusoids assisted empirical mode decomposition is introduced to decompose a fringe pattern, and subsequently, a new noise-signal-background classification strategy is proposed. The former avoids the mode-mixing problem appearing during the decomposition, while the latter adaptively classifies the decomposition results to remove the noise and background. The proposed method is testified by both simulation and real experiments, which shows effective and robust for fringe pattern analysis under different noise, fringe modulation, and defects.

  20. Fringe tracking at longer wavelengths using near- and mid-IR integrated optics devices

    NASA Astrophysics Data System (ADS)

    Muthusubramanian, Balaji; Labadie, Lucas; Pott, Jörg-Uwe; Tepper, Jan; Minardi, Stefano; Diener, Romina

    2016-08-01

    Fringe tracking at longer wavelengths is advantageous for its larger Fried parameter (R0) and longer coherence time (τ0). The fringe trackers which are currently available at the VLTi (Finito, FSU, Gravity, etc.) tracks fringes at the near infrared wavelengths (H and K bands). In our work we try to explore the possibilities to track near and mid- infrared fringes using GLS based laser written integrated optics beam combiners. We simulate the atmospheric optical path difference (OPD) using Kolmogorov/Von-Karman atmospheric turbulence statistics. We also include the measured the piston noise generated due to the instrumental vibrations. Using the resulting OPD time series we can estimate the sensitivity of the fringe tracker at the L band.

  1. Application of a Fringe Capacitive Sensor to Small-Distance Measurement

    NASA Astrophysics Data System (ADS)

    Wang, Dau-Chung; Chou, Jung-Chuan; Wang, Shih-Ming; Lu, Po-Lun; Liao, Lan-Pin

    2003-09-01

    In this paper, we used a fringe capacitive sensor to measure a short-distance variation of a target. High-precision displacement measurement was carried out based on the small fringing capacitance of the sensor measured. Sensing sensitivity was 38 μV/μm when the measurement was carried out in the distance range from 75 to 150 μm, which is the distance range between the sensor and the target. The sensitivity of the fringing capacitor is affected by its dimension, linewidth, and pattern. A printed circuit board (PCB)-based fabrication process was used to fabricate fringing capacitive sensors of various patterns. A simple and low cost sensing circuit transformed fringing capacitances into voltage output signal, which is also called capacitance-to-voltage (C/V) conversion. We accomplished the short-distance measurement with precision up to a submicron level.

  2. Dispersion interferometer using modulation amplitudes on LHD (invited)

    SciTech Connect

    Akiyama, T. Yasuhara, R.; Kawahata, K.; Okajima, S.; Nakayama, K.

    2014-11-15

    Since a dispersion interferometer is insensitive to mechanical vibrations, a vibration compensation system is not necessary. The CO{sub 2} laser dispersion interferometer with phase modulations on the Large Helical Device utilizes the new phase extraction method which uses modulation amplitudes and can improve a disadvantage of the original dispersion interferometer: measurement errors caused by variations of detected intensities. The phase variation within ±2 × 10{sup 17} m{sup −3} is obtained without vibration compensation system. The measured line averaged electron density with the dispersion interferometer shows good agreement with that with the existing far infrared laser interferometer. Fringe jump errors in high density ranging up to 1.5 × 10{sup 20} m{sup −3} can be overcome by a sufficient sampling rate of about 100 kHz.

  3. Dispersion interferometer using modulation amplitudes on LHD (invited).

    PubMed

    Akiyama, T; Yasuhara, R; Kawahata, K; Okajima, S; Nakayama, K

    2014-11-01

    Since a dispersion interferometer is insensitive to mechanical vibrations, a vibration compensation system is not necessary. The CO2 laser dispersion interferometer with phase modulations on the Large Helical Device utilizes the new phase extraction method which uses modulation amplitudes and can improve a disadvantage of the original dispersion interferometer: measurement errors caused by variations of detected intensities. The phase variation within ±2 × 10(17) m(-3) is obtained without vibration compensation system. The measured line averaged electron density with the dispersion interferometer shows good agreement with that with the existing far infrared laser interferometer. Fringe jump errors in high density ranging up to 1.5 × 10(20) m(-3) can be overcome by a sufficient sampling rate of about 100 kHz.

  4. Materials for Advanced Turbine Engines (MATE): Project 3: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner, volume 1

    NASA Technical Reports Server (NTRS)

    Henricks, R. J.; Sheffler, K. D.

    1984-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Incoloy MA 956 (FeCrAl base) and Haynes Developmental Alloy (HDA) 8077 (NiCrAl base) were evaluated. Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. Both alloys demonstrated a +167C (300 F) advantage of creep and oxidation resistance with no improvement in thermal fatigue capability compared to a current generation combustor alloy (Hastelloy X). MA956 alloy was selected for further demonstration because it exhibited better manufacturing reproducibility than HDA8077. Additional property tests were conducted on MA956. To accommodate the limited thermal fatigue capability of ODS alloys, two segmented, mechanically attached, low strain ODS combustor design concepts having predicted fatigue lives or = 10,000 engine cycles were identified. One of these was a relatively conventional louvered geometry, while the other involved a transpiration cooled configuration. A series of 10,000 cycle combustor rig tests on subscale MA956 and Hastelloy X combustor components showed no cracking, thereby confirming the beneficial effect of the segmented design on thermal fatigue capability. These tests also confirmed the superior oxidation and thermal distortion resistance of the ODS alloy. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components was designed and constructed.

  5. 3D surface real-time measurement using phase-shifted interference fringe technique for craniofacial identification

    NASA Astrophysics Data System (ADS)

    Levin, Gennady G.; Vishnyakov, Gennady N.; Naumov, Alexey V.; Abramov, Sergey

    1998-03-01

    We offer to use the 3D surface profile real-time measurement using phase-shifted interference fringe projection technique for the cranioficial identification. Our system realizes the profile measurement by projecting interference fringe pattern on the object surface and by observing the deformed fringe pattern at the direction different from the projection. Fringes are formed by a Michelson interferometer with one mirror mounted on a piezoelectric translator. Four steps self- calibration phase-shift method was used.

  6. Adaptive DFT-based fringe tracking and prediction at IOTA

    NASA Astrophysics Data System (ADS)

    Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

    2004-10-01

    An automatic fringe tracking system has been developed and implemented at the Infrared Optical Telescope Array (IOTA). In testing during May 2002, the system successfully minimized the optical path differences (OPDs) for all three baselines at IOTA. Based on sliding window discrete Fourier transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on off-line data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. Preliminary analysis on an extension of this algorithm indicates a potential for predictive tracking, although at present, real-time implementation of this extension would require significantly more computational capacity.

  7. Observations of infragravity motions for reef fringed islands and atolls

    NASA Astrophysics Data System (ADS)

    Becker, J. M.; Merrifield, M. A.; Ford, M.

    2012-12-01

    The frequency of flooding events that affect low lying islands and atolls in the Pacific is expected to increase under current sea level rise projections. Infragravity (IG) motions, with periods ranging from approximately 25 to 400 seconds, are an important component of wave driven flooding events for reef fringed islands and atolls. The IG variability during wave events is analyzed and interpreted dynamically from pressure and current observations at four cross-reef transects in the North Pacific Ocean that include sites in the Republic of the Marshall Islands and Guam. The IG motions are shown to depend upon the spectral properties of the incident wave forcing and reef flat characteristics that include reef flat length (ranging from 100m to 450m at the four sites) and total water level due to setup and tides. A small inundation event at one of the sites is shown to occur due to large shoreline infragravity energy.

  8. Rapid matching of stereo vision based on fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Zhang, Ruihua; Xiao, Yi; Cao, Jian; Guo, Hongwei

    2016-09-01

    As the most important core part of stereo vision, there are still many problems to solve in stereo matching technology. For smooth surfaces on which feature points are not easy to extract, this paper adds a projector into stereo vision measurement system based on fringe projection techniques, according to the corresponding point phases which extracted from the left and right camera images are the same, to realize rapid matching of stereo vision. And the mathematical model of measurement system is established and the three-dimensional (3D) surface of the measured object is reconstructed. This measurement method can not only broaden application fields of optical 3D measurement technology, and enrich knowledge achievements in the field of optical 3D measurement, but also provide potential possibility for the commercialized measurement system in practical projects, which has very important scientific research significance and economic value.

  9. Adaptive DIT-Based Fringe Tracking and Prediction at IOTA

    NASA Technical Reports Server (NTRS)

    Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

    2004-01-01

    An automatic fringe tracking system has been developed and implemented at the Infrared Optical Telescope Array (IOTA). In testing during May 2002, the system successfully minimized the optical path differences (OPDs) for all three baselines at IOTA. Based on sliding window discrete Fourier transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on off-line data. Implemented in ANSI C on the 266 MHZ PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. Preliminary analysis on an extension of this algorithm indicates a potential for predictive tracking, although at present, real-time implementation of this extension would require significantly more computational capacity.

  10. 3D shape measurement with phase correlation based fringe projection

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Munckelt, Christoph; Heinze, Matthias; Bräuer-Burchardt, Christian; Notni, Gunther

    2007-06-01

    Here we propose a method for 3D shape measurement by means of phase correlation based fringe projection in a stereo arrangement. The novelty in the approach is characterized by following features. Correlation between phase values of the images of two cameras is used for the co-ordinate calculation. This work stands in contrast to the sole usage of phase values (phasogrammetry) or classical triangulation (phase values and image co-ordinates - camera raster values) for the determination of the co-ordinates. The method's main advantage is the insensitivity of the 3D-coordinates from the absolute phase values. Thus it prevents errors in the determination of the co-ordinates and improves robustness in areas with interreflections artefacts and inhomogeneous regions of intensity. A technical advantage is the fact that the accuracy of the 3D co-ordinates does not depend on the projection resolution. Thus the achievable quality of the 3D co-ordinates can be selectively improved by the use of high quality camera lenses and can participate in improvements in modern camera technologies. The presented new solution of the stereo based fringe projection with phase correlation makes a flexible, errortolerant realization of measuring systems within different applications like quality control, rapid prototyping, design and CAD/CAM possible. In the paper the phase correlation method will be described in detail. Furthermore, different realizations will be shown, i.e. a mobile system for the measurement of large objects and an endoscopic like system for CAD/CAM in dental industry.

  11. Utilization characteristics and importance of woody biomass resources on the rural-urban fringe in botswana.

    PubMed

    Nkambwe, Musisi; Sekhwela, Mogodisheng B M

    2006-02-01

    This article examines the utilization characteristics and importance of woody biomass resources in the rural-urban fringe zones of Botswana. In the literature for Africa, attention has been given to the availability and utilization of biomass in either urban or rural environments, but the rural-urban fringe has been neglected. Within southern Africa, this neglect is not justified; the rural-urban fringe, not getting the full benefits available in urban environments in Botswana, has developed problems in woody biomass availability and utilization that require close attention. In this article, socioeconomic data on the importance of woody biomass in the Batlokwa Tribal Territory, on the rural-urban fringe of Gaborone, Botswana, were collected together with ecologic data that reveal the utilization characteristics and potential for regrowth of woody biomass. The analysis of these results show that local woody biomass is very important in the daily lives of communities in the rural-urban fringe zones and that there is a high level of harvesting. However, there is no effort in planning land use in the tribal territory to either conserve this resource or provide alternatives to its utilization. The future of woody biomass resources in Botswana's rural-urban fringe is uncertain. The investigators recommend that a comprehensive policy for the development of the rural-urban fringe consider the importance of this resource. The neglect of this resource will have far-reaching implications on the livelihoods of residents as well as the environment in this zone.

  12. Three-dimensional micro-topography by Talbot-projected fringes

    NASA Astrophysics Data System (ADS)

    Rayas, J. A.; Rodriguez-Vera, R.; Martinez, Amalia

    2006-02-01

    Implementation of a structured light projection technique for measuring the relief of objects, or object areas, of micrometric size (approximately 500 μm x 500 μm), is described. It is well-known that when a fringe pattern is projected on an object, the fringes are deformed according to the topography of its surface. This deformed fringe pattern is a modulated optical signal that allows us to measure the relief of the object. Through one of the oculars of a stereomicroscope, previously focused on the object under study, the fringe pattern of one the Talbot self-image is projected. The deformed fringe patterns are observed by the other ocular, in which a CCD camera is mounted to digitize them. Digitized fringe patterns are demodulated by means of a second virtual reference grating. As a result, a moire fringe pattern is obtained delivering a wrapped phase map when is digitally processed by means of a phase recover technique. Phase recovery techniques for obtaining the wrapped phase maps are phase-shifting and spatial phase synchronous. Experimental results and the conditions, under which the topography of an object section is determined, are shown. Also, comparisons over quality between the phase recovery techniques are discussed.

  13. Electron beam moiré fringes imaging by image converter tube with a magnetic lens

    NASA Astrophysics Data System (ADS)

    Liao, Yubo; Lei, Yunfei; Cai, Houzhi; Bai, Yanli; Liu, Jinyuan

    2016-06-01

    An image converter tube with a magnetic lens was used to obtain static images of moiré fringes formed by electron beam. These moiré fringes are formed due to the interference between the anode mesh and the photocathode containing slits of various spatial frequencies. Moiré fringes are observed at an accelerating voltage of 3.5 kV requiring the magnetic excitation condition of ˜550 ampere-turns. Not only the features of the fringes are analyzed but also the change of fringe spacing as a function of the rotation angle is investigated. The experimental results are found well in agreement with the theoretical analysis. By changing the rotation angle or adjusting the excitation condition of the magnetic lens, we were able to record parallel moiré and secondary moiré fringes too. The secondary moiré fringes can be observed in the rotation angle range of -39.5° to -50.6°. The theoretical analysis indicates that the secondary moiré is formed by the interference between the photocathode slits and the 2-D periodic structure of the anode mesh. Combining our proposed moiré method with the pulse-dilation technique may potentially open the door for future applications, in various fields including, but not limited to, ultrafast electrical pulse diagnostics.

  14. Use of the fast Fourier transform method for analyzing linear and equispaced Fizeau fringes.

    PubMed

    Lai, G; Yatagai, T

    1994-09-01

    The Fourier transform method is applied to analyze the initial phase of linear and equispaced Fizeau fringes. We develop an algorithm for high-precision phase measurement by using the Fourier coefficient that corresponds to the spatial frequency of the Fizeau fringes, and we describe methods for determining the fringe carrier frequency. Errors caused by carrier frequency fluctuation and data truncation are studied theoretically and by computer simulation. To demonstrate the method we apply it to the real-time calibration of a piezoelectric transducer mirror in a Twyman-Green interferometer.

  15. Visualizing the conoscopic isochromatic interference fringes in anisotropic crystals by spinning polarizer and analyzer.

    PubMed

    Wang, Pengqian

    2012-11-01

    In conventional conoscopic interference patterns of optically anisotropic materials the isochromatic interference fringes are inherently masked by the dark isogyres. We prove that the isochromatic fringes can be directly visualized by spinning the crossed linear polarizer and analyzer, regardless of the polarization state of the incident light. This simple method completely eliminates the isogyres and reveals the whole isochromatic fringes without the need of any additional optical elements or calculations. The system works at any wavelength that the linear polarizer permits. The validity of this method is demonstrated by observing the interference patterns of an LiNbO(3) electro-optic crystal under different external electric fields.

  16. The Impact of Masker Fringe and Masker Sparial Uncertainty on Sound Localization

    DTIC Science & Technology

    2010-09-01

    Dolan TR, Miller TE “Effect of ‘backward’ masker fringe on the detectability of pulsed diotic and dichotic tonal signals,” Percept & Psychophys 12:335...to the case in which the signal and masker are pulsed on/off simultaneously. This improvement has been attributed to the fact that the fringe...the signal and masker are pulsed on and off simultaneously [1,2]. It has been argued that this masker fringe provides a baseline set of stimulus

  17. Improvement of fringe quality at LDA measuring volume using compact two hololens imaging system

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Nirala, A. K.

    2015-03-01

    Design, analysis and construction of an LDA optical setup using conventional as well as compact two hololens imaging system have been performed. Fringes formed at measurement volume by both the imaging systems have been recorded. After experimentally analyzing these fringes, it is found that fringes obtained using compact two hololens imaging system get improved both qualitatively and quantitatively compared to that obtained using conventional imaging system. Hence it is concluded that use of the compact two hololens imaging system for making LDA optical setup is a better choice over the conventional one.

  18. Boundary-layer transition and global skin friction measurement with an oil-fringe imaging technique

    NASA Technical Reports Server (NTRS)

    Monson, Daryl J.; Mateer, George G.; Menter, Florian R.

    1993-01-01

    A new oil-fringe imaging system skin friction (FISF) technique to measure skin friction on wind tunnel models is presented. In the method used to demonstrate the technique, lines of oil are applied on surfaces that connect the intended sets of measurement points, and then a wind tunnel is run so that the oil thins and forms interference fringes that are spaced in proportion to local skin friction. After a run the fringe spacings are imaged with a CCD-array digital camera and measured on a computer. Skin friction and transition measurements on a two-dimensional wing are presented and compared with computational predictions.

  19. REMOVAL OF SPECTRO-POLARIMETRIC FRINGES BY TWO-DIMENSIONAL PATTERN RECOGNITION

    SciTech Connect

    Casini, R.; Judge, P. G.; Schad, T. A.

    2012-09-10

    We present a pattern-recognition-based approach to the problem of the removal of polarized fringes from spectro-polarimetric data. We demonstrate that two-dimensional principal component analysis can be trained on a given spectro-polarimetric map in order to identify and isolate fringe structures from the spectra. This allows us, in principle, to reconstruct the data without the fringe component, providing an effective and clean solution to the problem. The results presented in this paper point in the direction of revising the way that science and calibration data should be planned for a typical spectro-polarimetric observing run.

  20. Determination of slope, curvature, and twist from a single shearography fringe pattern using derivative-based regularized phase tracker

    NASA Astrophysics Data System (ADS)

    Deepan, Balakrishnan; Quan, Chenggen; Tay, Cho Jui

    2016-12-01

    A fringe analysis algorithm for determination of slope, curvature, and twist from a single fringe pattern in digital speckle-shearing interferometry is proposed. A method for estimation of biased curvature and twist maps from fringe orientation and fringe density maps is employed. The curvature and twist maps obtained are further processed by B-spline interpolation to achieve high quality curvature and twist maps. A derivative-based regularized phase tracker (RPT) utilizes these predetermined curvature and twist maps for determination of a slope map from a single shearography fringe pattern. The proposed model requires less computational time and it overcomes the limitations of the RPT model. The method is validated with an experimental fringe pattern. The results show that this method is robust against speckle noise and it is able to retrieve accurate slope, curvature, and twist maps from a single shearography fringe pattern.

  1. Fringe Capacitance Correction for a Coaxial Soil Cell

    PubMed Central

    Pelletier, Mathew G.; Viera, Joseph A.; Schwartz, Robert C.; Lascano, Robert J.; Evett, Steven R.; Green, Tim R.; Wanjura, John D.; Holt, Greg A.

    2011-01-01

    Accurate measurement of moisture content is a prime requirement in hydrological, geophysical and biogeochemical research as well as for material characterization and process control. Within these areas, accurate measurements of the surface area and bound water content is becoming increasingly important for providing answers to many fundamental questions ranging from characterization of cotton fiber maturity, to accurate characterization of soil water content in soil water conservation research to bio-plant water utilization to chemical reactions and diffusions of ionic species across membranes in cells as well as in the dense suspensions that occur in surface films. One promising technique to address the increasing demands for higher accuracy water content measurements is utilization of electrical permittivity characterization of materials. This technique has enjoyed a strong following in the soil-science and geological community through measurements of apparent permittivity via time-domain-reflectometry (TDR) as well in many process control applications. Recent research however, is indicating a need to increase the accuracy beyond that available from traditional TDR. The most logical pathway then becomes a transition from TDR based measurements to network analyzer measurements of absolute permittivity that will remove the adverse effects that high surface area soils and conductivity impart onto the measurements of apparent permittivity in traditional TDR applications. This research examines an observed experimental error for the coaxial probe, from which the modern TDR probe originated, which is hypothesized to be due to fringe capacitance. The research provides an experimental and theoretical basis for the cause of the error and provides a technique by which to correct the system to remove this source of error. To test this theory, a Poisson model of a coaxial cell was formulated to calculate the effective theoretical extra length caused by the fringe capacitance

  2. Fiber-optic project-fringe interferometry with sinusoidal phase modulating system

    NASA Astrophysics Data System (ADS)

    Zhang, Fukai; Duan, Fajie; Lv, Changrong; Duan, Xiaojie; Bo, En; Feng, Fan

    2013-06-01

    A fiber-optic sinusoidal phase-modulating (SPM) interferometer for fringe projection is presented. The system is based on the SPM technique and makes use of the Mach-Zehnder interferometer structure and Young's double pinhole interference principle to achieve interference fringe projection. A Michelson interferometer, which contains the detection of Fresnel reflection on its fiber end face and interference at one input port of a 3 dB coupler, is utilized to achieve feedback precise control of the fringe phase, which is sensitive to phase drifting produced by the nature of the fiber. The phase diversity for the closed-loop SPM system can be real-time measured with a precision of 3 mrad. External disturbances mainly caused by temperature fluctuations can be reduced to 57 mrad for the fringe map. The experimental results have shown the usefulness of the system.

  3. Two-beam prism interferometer for noise-free fringe generation.

    PubMed

    Ichikawa, H

    1994-01-01

    A triangular prism instead of a beam splitter was used in a Twyman-Green interferometer to improve fringe quality by removing multiple reflection. The basic principle and its performance are discussed.

  4. Real-time fringe pattern demodulation with a second-order digital phase-locked loop.

    PubMed

    Gdeisat, M A; Burton, D R; Lalor, M J

    2000-10-10

    The use of a second-order digital phase-locked loop (DPLL) to demodulate fringe patterns is presented. The second-order DPLL has better tracking ability and more noise immunity than the first-order loop. Consequently, the second-order DPLL is capable of demodulating a wider range of fringe patterns than the first-order DPLL. A basic analysis of the first- and the second-order loops is given, and a performance comparison between the first- and the second-order DPLL's in analyzing fringe patterns is presented. The implementation of the second-order loop in real time on a commercial parallel image processing system is described. Fringe patterns are grabbed and processed, and the resultant phase maps are displayed concurrently.

  5. Nitrogen dynamics in subtropical fringe and basin mangrove forests inferred from stable isotopes.

    PubMed

    Reis, Carla Roberta Gonçalves; Nardoto, Gabriela Bielefeld; Rochelle, André Luis Casarin; Vieira, Simone Aparecida; Oliveira, Rafael Silva

    2017-03-01

    Mangroves exhibit low species richness compared to other tropical forests, but great structural and functional diversity. Aiming to contribute to a better understanding of the functioning of mangrove forests, we investigated nitrogen (N) dynamics in two physiographic types of mangroves (fringe and basin forests) in southeastern Brazil. Because fringe forests are under great influence of tidal flushing we hypothesized that these forests would exhibit higher N cycling rates in sediment and higher N losses to the atmosphere compared to basin forests. We quantified net N mineralization and nitrification rates in sediment and natural abundance of N stable isotopes (δ(15)N) in the sediment-plant-litter system. The fringe forest exhibited higher net N mineralization rates and δ(15)N in the sediment-plant-litter system, but net nitrification rates were similar to those of the basin forest. The results of the present study suggest that fringe forests exhibit higher N availability and N cycling in sediment compared to basin forests.

  6. 3D shape measurement of optical free-form surface based on fringe projection

    NASA Astrophysics Data System (ADS)

    Li, Shaohui; Liu, Shugui; Zhang, Hongwei

    2011-05-01

    Present a novel method of 3D shape measurement of optical free-from surface based on fringe projection. A virtual reference surface is proposed which can be used to improve the detection efficiency and realize the automation of measuring process. Sinusoidal fringe patterns are projected to the high reflected surface of the measured object. The deflection fringe patterns that modulated by the object surface are captured by the CCD camera. The slope information can be obtained by analyzing the relationship between the phase deflectometry and the slope of the object surface. The wave-front reconstruction method is used to reconstruct the surface. With the application of fringe projection technology the accuracy of optical free-form surfaces measurement could reach the level of tens of micrometer or even micrometer.

  7. Two-dimensional discrete wavelets transform for optical phase extraction: application on speckle correlation fringes

    NASA Astrophysics Data System (ADS)

    Ghlaifan, Abdulatef; Tounsi, Yassine; Zada, Sara; Muhire, Desire; Nassim, Abdelkrim

    2016-12-01

    A method for optical phase extraction based on two-dimensional discrete wavelets transform (2-DWT) decomposition is shown. From modulated fringe pattern, phase distribution is extracted by the ratio between detail and approximation. Modulation process is realized digitally by introducing high-frequency spatial carrier, and this process needs two π/2-shifted fringe patterns. We propose to use only single fringe and generate its quadrature by spiral phase transform (SPT). After validation by computer simulation, we apply the 2-DWT algorithm on experimental speckle fringe correlation taken for hard disk surface. The extracted phase using SPT quadrature was compared with that given using this time experimental quadrature, and we show a good performance by multiscale structural similarity metric.

  8. On the fringing-field effect in liquid-crystal beam-steering devices.

    PubMed

    Apter, Boris; Efron, Uzi; Bahat-Treidel, Eldad

    2004-01-01

    A detailed simulation of the fringing-field effect in liquid-crystal (LC)-based blazed-grating structures has been carried out. These studies are aimed at clarifying the relationship between the width of the fringing-field-broadened phase profile of the blazed grating and the LC cell thickness. This fringing-field broadening of the blazed grating's phase profile is shown to affect mostly the 2pi phase-step zone (fly-back zone) of the blazed grating. The results of the simulations carried out on the blazed-grating structure indicate two main effects of the fringing field: (1) reduction in the attainable diffraction efficiency and (2) limitation of the maximum deflection angle of the device. Both effects are shown to be directly linked to the broadening of the fly-back zone, which is shown to be proportional to the LC cell thickness.

  9. High-quality 3D shape measurement using saturated fringe patterns

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Zhang, Song

    2016-12-01

    This paper proposes a method to potentially conquer one of the challenges in the optical metrology community: optically measuring three-dimensional (3D) objects with high surface contrast. We discover that for digitally equally phase-shifted fringe patterns, if the fringe period P is an even number, the N = P / 2 × k , (k=1, 2, 3, …) step algorithm can accurately recover phase even if the fringe patterns are saturated; and if P is an odd number, N = P × k step algorithm can also accurately recover phase even if the fringe patterns are saturated. This finding leads to a novel method to optically measure shiny surfaces, where the saturation due to surface shininess could be substantially alleviated. Both simulations and experiments successfully verified the proposed method.

  10. APPLICATION OF THE NATURALLY-OCCURRING DEUTERIUM ISOTOPE TO TRACING THE CAPILLARY FRINGE

    EPA Science Inventory

    Naturally-occurring deuterium is a useful tracer of subsurface hydrologic processes. A possible application includes the identification of capillary fringes in the vadose zone. Multiple and discontinuous water tables persist in many temperate regions, under various hydrogeologi...

  11. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... in the fringe benefit determination are the reference points for determining whether an employee is... holidays are the reference points for determining whether an employee is eligible to receive...

  12. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... in the fringe benefit determination are the reference points for determining whether an employee is... holidays are the reference points for determining whether an employee is eligible to receive...

  13. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... in the fringe benefit determination are the reference points for determining whether an employee is... holidays are the reference points for determining whether an employee is eligible to receive...

  14. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... in the fringe benefit determination are the reference points for determining whether an employee is... holidays are the reference points for determining whether an employee is eligible to receive...

  15. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... in the fringe benefit determination are the reference points for determining whether an employee is... holidays are the reference points for determining whether an employee is eligible to receive...

  16. Caddisflies (Insecta: Trichoptera) of fringing wetlands of the Laurentian Great Lakes

    USGS Publications Warehouse

    Armitage, Brian J.; Hudson, Patrick L.; Wilcox, Douglas A.

    2001-01-01

    Fringing wetlands of the Laurentian Great Lakes are subject to natural processes, such as water-level fluctuation and wave-induced erosion, and to human alterations. In order to evaluate the quality of these wetlands over space and time, biological communities are often examined. This paper reports on the use of adult caddisflies to evaluate fringing wetlands of Lake Huron, Lake Michigan, and Lake Superior.

  17. Fringe-projection method for three-dimensional digitization of human faces

    NASA Astrophysics Data System (ADS)

    Picos, Kenia; Juarez-Salazar, Rigoberto; Díaz-Ramírez, Víctor H.

    2016-09-01

    A reliable method for three-dimensional digitization of human faces based on the fringe projection technique is presented. The proposed method employs robust fringe analysis algorithms for robust phase computation. The quality of the resultant 3D face model is characterized in terms of accuracy of surface computation using objective metrics. We present experimental results obtained with real and synthetic laboratory objects. The potential of this method to be used in the field of face recognition is discussed.

  18. Analysis of closed fringe patterns for aspheric surface measurement

    NASA Astrophysics Data System (ADS)

    Nie, Liang; Liu, Baoyuan; Han, Jun; Yu, Xun

    2010-10-01

    The closed fringe patterns analysis is difficult to handle, especially in interferometer for aspheric surface measurement. Two-dimensional fast Fourier transform (FFT) algorithm is proposed to extract interferogram phase in this paper. The principle and process of FFT method is described and the computer simulation proves its validity. Some key techniques are researched, such as the filter design and the elimination of prejudicial error. In order to eliminate the effect of the abrupt change in the wrapped phase map, the rectangular low-pass filters with different directions and image stitching technology are applied. To reduce spectral leakage, filter design and determination method of phase mutation position are discussed. The unwrapped phase distribution is got by the unweighted least-squares phase unwrapping algorithm and the error of spherical figure is derived from the fitting method of Zernike polynomials. The simulation results show that the method is up to high precision. The methods are used to treat the aspheric surface measurement in experiment. The results of processing the aspheric surface interferograms in a zone-plate interferometer indicate that the methods have achieved worthy measurement precision and have great development potential.

  19. Adaptive threshold selection for background removal in fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Li, Weishi; Yan, Jianwen; Yu, Liandong; Pan, Chengliang

    2017-03-01

    In fringe projection profilometry, background and shadow are inevitable in the image of an object, and must be identified and removed. In existing methods, it is nontrivial to determine a proper threshold to segment the background and shadow regions, especially when the gray-level histogram of the image is close to unimodal, and an improper threshold generally results in misclassification of the object and the background/shadow. In this paper, an adaptive threshold method is proposed to tackle the problem. Different from the existing automatic methods, the modulation-level histogram, instead of the gray-level histogram, of the image is employed to determine the threshold. Furthermore, a new weighting factor is proposed to improve Otsu's method to segment the image with a histogram close to unimodal, and the modulation difference of the object pixels and the background/shadow pixels is intensified significantly by the weighting factor. Moreover, the weighting factor is adaptive to the image. The proposed method outperforms existing methods either in accuracy, efficiency or automation. Experimental results are given to demonstrate the feasibility and effectiveness of the proposed method.

  20. Decadal coral community reassembly on an African fringing reef

    NASA Astrophysics Data System (ADS)

    McClanahan, T. R.

    2014-12-01

    Changes in the cover of the dominant hard coral taxa were studied on seven Kenyan back reefs over 20 yr. All factors of time, taxa, site, and their interactions were statistically significant and the 1998 temperature anomaly caused the greatest community changes. The 1998 disturbance changes reflected a classic coral succession, which included partial or little mortality and persistence of stress tolerant (massive and submassive growth forms) and early colonization by weedy taxa (pocilloporids). Nevertheless, competitive taxa had high and full mortality and the expected dominance of acroporids was inhibited even ~13 yr after the disturbance. So, while total hard coral cover displayed the expected logistic recovery where maximum cover was reached <10 yr after the disturbance, the poor recovery of competitive dominants resulted in less than expected coral cover. A number of stress-resistant and weedy taxa (poritids, agaricidae, faviids, and pocilloporids) are expected to dominate the composition of these reefs in the future. Nevertheless, three submassive faviids and branching Porites began to decline toward the end of the time series, indicating further stress after 1998. Increased algal cover and other unstudied factors, including milder warming, may explain these changes. The patterns of change on this continental fringing reef differ from recovery of more remote, offshore islands. This probably reflects low acroporid dominance and recruitment limitations associated with greater anthropogenic influences of high sea urchin grazing and terrestrial runoff.

  1. Experimental sensitivity analysis of oxygen transfer in the capillary fringe.

    PubMed

    Haberer, Christina M; Cirpka, Olaf A; Rolle, Massimo; Grathwohl, Peter

    2014-01-01

    Oxygen transfer in the capillary fringe (CF) is of primary importance for a wide variety of biogeochemical processes occurring in shallow groundwater systems. In case of a fluctuating groundwater table two distinct mechanisms of oxygen transfer within the capillary zone can be identified: vertical predominantly diffusive mass flux of oxygen, and mass transfer between entrapped gas and groundwater. In this study, we perform a systematic experimental sensitivity analysis in order to assess the influence of different parameters on oxygen transfer from entrapped air within the CF to underlying anoxic groundwater. We carry out quasi two-dimensional flow-through experiments focusing on the transient phase following imbibition to investigate the influence of the horizontal flow velocity, the average grain diameter of the porous medium, as well as the magnitude and the speed of the water table rise. We present a numerical flow and transport model that quantitatively represents the main mechanisms governing oxygen transfer. Assuming local equilibrium between the aqueous and the gaseous phase, the partitioning process from entrapped air can be satisfactorily simulated. The different experiments are monitored by measuring vertical oxygen concentration profiles at high spatial resolution with a noninvasive optode technique as well as by determining oxygen fluxes at the outlet of the flow-through chamber. The results show that all parameters investigated have a significant effect and determine different amounts of oxygen transferred to the oxygen-depleted groundwater. Particularly relevant are the magnitude of the water table rise and the grain size of the porous medium.

  2. Controlling Fringe Sensitivity of Electro-Optic Holography Systems Using Laser Diode Current Modulation

    NASA Technical Reports Server (NTRS)

    Bybee, Shannon J.

    2001-01-01

    Electro-Optic Holography (EOH) is a non-intrusive, laser-based, displacement measurement technique capable of static and dynamic displacement measurements. EOH is an optical interference technique in which fringe patterns that represent displacement contour maps are generated. At excessively large displacements the fringe density may be so great that individual fringes are not resolvable using typical EOH techniques. This thesis focuses on the development and implementation of a method for controlling the sensitivity of the EOH system. This method is known as Frequency Translated Electro-Optic Holography (FTEOH). It was determined that by modulating the current source of the laser diode at integer multiples of the object vibration, the fringe pattern is governed by higher order Bessel function of the first kind and the number of fringes that represent a given displacement can be controlled. The reduction of fringes is theoretically unlimited but physically limited by the frequency bandwidth of the signal generator, providing modulation to the laser diode. Although this research technique has been verified theoretically and experimentally in this thesis, due to the current laser diode capabilities it is a tedious and time consuming process to acquire data using the FTEOH technique.

  3. Investigation on the formation of intense fringe near nonlinear medium slab in nonlinear imaging

    NASA Astrophysics Data System (ADS)

    Hu, Yonghua; Qiu, Yaqiong; Peng, Xue

    2016-11-01

    It is well known that hot images of small-scale scatterers can be formed. For phase-typed scatterers, hot image and second-order hot-image can be formed. However, when the number of scatterer is larger than one, the interaction between the scatterered waves will lead to new nonlinear propagation results. In this paper, the propagation of flat-topped intense laser beam through Kerr medium slab is investigated, with the incident beam modulated by two parallel wirelike phase-typed scatterers. We demonstrate that an intense fringe together with hot image and second-order hot image can be formed when the distance of the two scatterers is several millimeters. It is found that the on-axis position of the plane of this intense fringe is in the middle part between the exit surface of the Kerr medium slab and the secondorder hot image plane. This intense fringe shows the following basic properties: Firstly, its intensity is apparently higher than that of corresponding second-order hot image and can be comparable with that of corresponding hot image; Secondly, the distances between it and the in-beam positions of the scatterers are identical. The intensity profile shows that this intense fringe is the only prominent bright fringe in the corresponding plane, and thus it is not a nonlinear image of any scatterer. Besides, the influences of the properties of scatterer on the intensity of the fringe are discussed.

  4. Dispersive coherence spectrotomography of a layered medium

    NASA Astrophysics Data System (ADS)

    Watanabe, Wataru; Itoh, Kazuyoshi

    1999-05-01

    In low-coherence reflectometry, the light backscattered from a scattering medium is expected to carry information about the spectral properties as well as range information about the reflective boundaries and backscattering sites. We show two alternative techniques to extract both the range and spectral properties of the sample by optically dispersed interferograms. The methods make the most of the brightness of white-light continuum, which is generated by focusing ultrashort laser pulses into condensed matters. The output beam from an interferometer is dispersed by a spectroscopic optical element and the dispersed signal is detected by a line detector. The salient feature of the methods is that the spectral decomposition of the white-light interferograms enhances the dynamic range and signal-to-noise ratio. One method is a scanning type. By translating a sample, spectrally-resolved interferograms are detected. Appropriate grouping of the interferograms yields both range and spectral properties of the sample. The other method is based on the principle of spectral radar due to Hausler. The spectrally- resolved fringes are acquired without scanning. The signal- processing allows us to display both the scattering amplitude and spectral properties within the bandwidth of the filters. Experimental results will be presented.

  5. Fringe Benefits for Superintendents in Public Schools, 1981-82. Part 1 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    To help school boards and superintendents assess fringe benefit packages in their districts, this fourth biennial survey presents data on nonsalary compensation for public school superintendents in a national stratified sample of 1,036 of the nation's 11,313 public school systems. Arrayed in 38 tables, the data are classified by district…

  6. Fringe Benefits for Superintendents in Public Schools, 1989-90. Part 1 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    A wide range of fringe benefit practices offered to superintendents are summarized in this report. Based on a national panel sample stratified by enrollment size, results are reported separately according to four enrollment groupings by size, per pupil expenditure, and geographic region. Data on leave policies, insurance coverage, retirement…

  7. Salaries and Fringe Benefits, Professional Personnel, 1974-1975. A Study of the Salary and Fringe Benefits for Selected Professional Personnel in Western New York.

    ERIC Educational Resources Information Center

    Western New York Regional Office for Educational Planning, Cheektowaga.

    This study is designed to provide educators with comprehensive and accurate information concerning the salary and fringe benefits of professional personnel of the school districts in the six counties of western New York State. A number of new items of information are introduced in this year's study. First, building enrollments are given for…

  8. Fringe Benefits for School Superintendents, 1975-76. Part I of National Survey of Fringe Benefits for Professional Personnel in Public Schools, 1975-76. ERS Report.

    ERIC Educational Resources Information Center

    Stieber, Gertrude N.

    This report contains information on 1,074 school systems that supplied usable data to the Educational Research Service, Inc. national survey of fringe benefits. The system-by-system listing includes data from 541 districts, the remaining 533 preferred to remain anonymous. The first section of the system-by-system listing is concerned mainly with…

  9. A computer controlled signal preprocessor for laser fringe anemometer applications

    NASA Technical Reports Server (NTRS)

    Oberle, Lawrence G.

    1987-01-01

    The operation of most commercially available laser fringe anemometer (LFA) counter-processors assumes that adjustments are made to the signal processing independent of the computer used for reducing the data acquired. Not only does the researcher desire a record of these parameters attached to the data acquired, but changes in flow conditions generally require that these settings be changed to improve data quality. Because of this limitation, on-line modification of the data acquisition parameters can be difficult and time consuming. A computer-controlled signal preprocessor has been developed which makes possible this optimization of the photomultiplier signal as a normal part of the data acquisition process. It allows computer control of the filter selection, signal gain, and photo-multiplier voltage. The raw signal from the photomultiplier tube is input to the preprocessor which, under the control of a digital computer, filters the signal and amplifies it to an acceptable level. The counter-processor used at Lewis Research Center generates the particle interarrival times, as well as the time-of-flight of the particle through the probe volume. The signal preprocessor allows computer control of the acquisition of these data.Through the preprocessor, the computer also can control the hand shaking signals for the interface between itself and the counter-processor. Finally, the signal preprocessor splits the pedestal from the signal before filtering, and monitors the photo-multiplier dc current, sends a signal proportional to this current to the computer through an analog to digital converter, and provides an alarm if the current exceeds a predefined maximum. Complete drawings and explanations are provided in the text as well as a sample interface program for use with the data acquisition software.

  10. Dynamics of Whale Shark Occurrence at Their Fringe Oceanic Habitat

    PubMed Central

    Afonso, Pedro; McGinty, Niall; Machete, Miguel

    2014-01-01

    Studies have shown that the whale shark (Rhincodon typus), a vulnerable large filter feeder, seasonally aggregates at highly productive coastal sites and that individuals can perform large, trans-boundary migrations to reach these locations. Yet, the whereabouts of the whale shark when absent from these sites and the potential oceanographic and biological drivers involved in shaping their present and future habitat use, including that located at the fringes of their suitable oceanic habitat, are largely unknown. We analysed a 16-year (1998–2013) observer dataset from the pole-and-line tuna fishery across the Azores (mid-North Atlantic) and used GAM models to investigate the spatial and temporal patterns of whale shark occurrence in relation to oceanographic features. Across this period, the whale shark became a regular summer visitor to the archipelago after a sharp increase in sighting frequency seen in 2008. We found that SST helps predicting their occurrence in the region associated to the position of the seasonal 22°C isotherm, showing that the Azores are at a thermal boundary for this species and providing an explanation for the post 2007 increase. Within the region, whale shark detections were also higher in areas of increased bathymetric slope and closer to the seamounts, coinciding with higher chl-a biomass, a behaviour most probably associated to increased feeding opportunities. They also showed a tendency to be clustered around the southernmost island of Santa Maria. This study shows that the region integrates the oceanic habitat of adult whale shark and suggests that an increase in its relative importance for the Atlantic population might be expected in face of climate change. PMID:25028929

  11. Dynamics of whale shark occurrence at their fringe oceanic habitat.

    PubMed

    Afonso, Pedro; McGinty, Niall; Machete, Miguel

    2014-01-01

    Studies have shown that the whale shark (Rhincodon typus), a vulnerable large filter feeder, seasonally aggregates at highly productive coastal sites and that individuals can perform large, trans-boundary migrations to reach these locations. Yet, the whereabouts of the whale shark when absent from these sites and the potential oceanographic and biological drivers involved in shaping their present and future habitat use, including that located at the fringes of their suitable oceanic habitat, are largely unknown. We analysed a 16-year (1998-2013) observer dataset from the pole-and-line tuna fishery across the Azores (mid-North Atlantic) and used GAM models to investigate the spatial and temporal patterns of whale shark occurrence in relation to oceanographic features. Across this period, the whale shark became a regular summer visitor to the archipelago after a sharp increase in sighting frequency seen in 2008. We found that SST helps predicting their occurrence in the region associated to the position of the seasonal 22°C isotherm, showing that the Azores are at a thermal boundary for this species and providing an explanation for the post 2007 increase. Within the region, whale shark detections were also higher in areas of increased bathymetric slope and closer to the seamounts, coinciding with higher chl-a biomass, a behaviour most probably associated to increased feeding opportunities. They also showed a tendency to be clustered around the southernmost island of Santa Maria. This study shows that the region integrates the oceanic habitat of adult whale shark and suggests that an increase in its relative importance for the Atlantic population might be expected in face of climate change.

  12. Electro-optical properties of a nematic liquid crystal cell by double-side fringe-field switching

    NASA Astrophysics Data System (ADS)

    Xiang, C. Y.; Sun, X. W.

    2004-09-01

    The electro-optical and response properties of a nematic liquid crystal cell driven by double-side fringe-field switching [C. Y. Xiang, X. W. Sun, and X. J. Yin, Appl. Phys. Lett. 83, 5154 (2003)] have been studied. The transmission-voltage curve of the double-side fringe-field cell can be modeled by the change of the maximum twist angle. It is shown that the liquid crystal layer is linearly twisted before the transmission reaches the maximum. The threshold voltage of double-side fringe-field switching is the same as that of single-side fringe-field switching. The turn-on and turn-off response times, showing four time improvement over the single-side fringe-field switching, have been derived. The experimental turn-off times of the double-sides fringe-field switching and single-side fringe-field switching cell match with the theoretical prediction. The experimental turn-on time of the double-side fringe-field switching cell shows four times improvement over the single-side fringe-field one as predicted by the theoretical analysis.

  13. An online triple-frequency color-encoded fringe projection profilometry for discontinuous object

    NASA Astrophysics Data System (ADS)

    Wan, Ying-Ying; Cao, Yi-Ping; Chen, Cheng; Peng, Kuang

    2016-08-01

    An online triple-frequency color-encoded fringe projection profilometry is proposed to measure the complex and discontinuous object at straight-line movement. N frames of color fringe patterns are specially designed. Three grayscale sinusoidal grating patterns with geometric progression frequency growth are encoded into red (R), green (G), and blue (B) channels separately to compose a color-encoded fringe pattern. If these three grayscale sinusoidal grating patterns are phase-shifted N steps with an equivalent shift phase of 2π/N, they can compose the corresponding N frames of color-encoded fringe patterns as above respectively. In order to avoid the movement's interference to the phase shifting, position adjustment should be done to guarantee the phase-shifting direction to be perpendicular to the moving direction. While these N frames of specially designed color-encoded fringe patterns are projected onto the moving object one by one, the corresponding deformed color patterns are captured by a CCD camera in real time. By color separating, color crosstalk compensation, pixel matching, and phase calculation, three wrapped phase at different frequencies can be extracted. The unwrapped phase can be solved by a simplified algorithm based on temporal phase unwrapping method from the relationship of the three wrapped phase at the same pixel. Thus, it is very suitable to measure the online complex and discontinuous objects at straight-line movement. The experimental results show the feasibility and the validity of the proposed method.

  14. Dynamic three-dimensional shape measurement for specular freeform surfaces with the quaternary orthogonal grid fringes

    NASA Astrophysics Data System (ADS)

    Xu, Xueyang; Zhang, Xiangchao; Xu, Min

    2016-10-01

    Deflectometry is a promising method for freeform surfaces due to its wide applications and ease of implementation, but it is not robust against environmental noise and vibrations. A new deflectometry method using the quaternary orthogonal grid fringes is proposed to retrieve the surface slopes. Combined with a classic N-step phase-shifting technique, only one image is required to extract the two perpendicular directional phases instead of two groups of phase shifted fringes. The color of each pixel can be encoded by red, green and blue components. In each color component, two perpendicular fringe patterns compose quaternary orthogonal grid fringes. In practice, the relative shift between different colors is set depending on the lateral resolution of the camera lens and the zoom relation of the object-image. The object-image relationship can be established by using only one distorted colorful orthogonal fringe pattern reflected via the surface. This process is fast and stable because the RGB codes of every block are significantly different to its neighbor in at least one color component. This method is suitable for dynamic measurement of specular objects, and the influence of varying environment and moving objects can then be eliminated.

  15. A derivative based simplified phase tracker for a single fringe pattern demodulation

    NASA Astrophysics Data System (ADS)

    Deepan, B.; Quan, C.; Tay, C. J.

    2016-08-01

    In this paper, a novel fringe demodulation method for the estimation of phase and its first-order derivative from a closed-fringe interferogram is proposed. The proposed method determines the phase derivatives in both x&y directions from fringe orientation and density. The phase derivatives are subsequently used to determine phase values using a novel simplified phase tracker. In the phase tracking model, the complexity of the cost function is reduced using predetermined derivatives so computation time required for phase tracking is reduced considerably. The proposed model is more robust while dealing with saddle points in fringes than the conventional phase tracker model. Hence it does not require any specialized scanning strategy. The proposed method is validated with simulated and experimental fringe patterns (obtained using electronic speckle pattern interferometry and optical holographic interferometry) and a comparison study is carried out with conventional regularized phase tracker. The simulation results show that the proposed method has good accuracy and requires less computation time than existing phase-tracking algorithms. The experimental results demonstrate the robustness of the proposed method against speckle noise and its practical applicability for static and dynamic applications.

  16. Demonstration of microbial transport into the capillary fringe via advection from below the water table

    NASA Astrophysics Data System (ADS)

    Dunn, Andrea M.; Silliman, Stephen E.; Dhamwichukorn, Srisuda; Kulpa, Charles F.

    2005-05-01

    A laboratory experiment is used to provide preliminary evidence that microbes can be advected into the capillary fringe from the region below the water table under steady flow conditions. A flow cell was packed so as to contain both a region for which pore-water pressure was greater than atmospheric pressure (termed 'below the water table') and a region, where the pore-water pressure was less than atmospheric with the pores essentially saturated with water (termed the 'capillary fringe'). Steady flow was then established through maintaining a hydraulic gradient across the medium. Green fluorescent protein (GFP) transformed bacteria ( E. coli JM109) were used to visualize migration of bacteria from below the water table into the capillary fringe. These transformed bacteria fluoresce brightly and readily when excited by standard UV light (395 nm) in 100 mL LB medium with 100 μg/mL ampicillin. The concentrations of bacterial inoculum and oxygen were adjusted to ensure GFPuv expression at a large scale. Results demonstrated that microbes can move into the capillary fringe from below the water table under horizontal hydraulic gradients. Motion from the capillary fringe into the region below the water table was also observed as was the absence of advection through regions of entrapped air below the water table.

  17. 3D fingerprint imaging system based on full-field fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Huang, Shujun; Zhang, Zonghua; Zhao, Yan; Dai, Jie; Chen, Chao; Xu, Yongjia; Zhang, E.; Xie, Lili

    2014-01-01

    As an unique, unchangeable and easily acquired biometrics, fingerprint has been widely studied in academics and applied in many fields over the years. The traditional fingerprint recognition methods are based on the obtained 2D feature of fingerprint. However, fingerprint is a 3D biological characteristic. The mapping from 3D to 2D loses 1D information and causes nonlinear distortion of the captured fingerprint. Therefore, it is becoming more and more important to obtain 3D fingerprint information for recognition. In this paper, a novel 3D fingerprint imaging system is presented based on fringe projection technique to obtain 3D features and the corresponding color texture information. A series of color sinusoidal fringe patterns with optimum three-fringe numbers are projected onto a finger surface. From another viewpoint, the fringe patterns are deformed by the finger surface and captured by a CCD camera. 3D shape data of the finger can be obtained from the captured fringe pattern images. This paper studies the prototype of the 3D fingerprint imaging system, including principle of 3D fingerprint acquisition, hardware design of the 3D imaging system, 3D calibration of the system, and software development. Some experiments are carried out by acquiring several 3D fingerprint data. The experimental results demonstrate the feasibility of the proposed 3D fingerprint imaging system.

  18. Adaptive automatic data analysis in full-field fringe-pattern-based optical metrology

    NASA Astrophysics Data System (ADS)

    Trusiak, Maciej; Patorski, Krzysztof; Sluzewski, Lukasz; Pokorski, Krzysztof; Sunderland, Zofia

    2016-12-01

    Fringe pattern processing and analysis is an important task of full-field optical measurement techniques like interferometry, digital holography, structural illumination and moiré. In this contribution we present several adaptive automatic data analysis solutions based on the notion of Hilbert-Huang transform for measurand retrieval via fringe pattern phase and amplitude demodulation. The Hilbert-Huang transform consists of 2D empirical mode decomposition algorithm and Hilbert spiral transform analysis. Empirical mode decomposition adaptively dissects a meaningful number of same-scale subimages from the analyzed pattern - it is a data-driven method. Appropriately managing this set of unique subimages results in a very powerful fringe pre-filtering tool. Phase/amplitude demodulation is performed using Hilbert spiral transform aided by the local fringe orientation estimator. We describe several optical measurement techniques for technical and biological objects characterization basing on the especially tailored Hilbert-Huang algorithm modifications for fringe pattern denoising, detrending and amplitude/phase demodulation.

  19. Artificial neural network approach for moiré fringe center determination

    NASA Astrophysics Data System (ADS)

    Woo, Wing Hon; Ratnam, Mani Maran; Yen, Kin Sam

    2015-11-01

    The moiré effect has been used in high-accuracy positioning and alignment systems for decades. Various methods have been proposed to identify and locate moiré fringes in order to relate the pattern information to dimensional and displacement measurement. These methods can be broadly categorized into manual interpretation based on human knowledge and image processing based on computational algorithms. An artificial neural network (ANN) is proposed to locate moiré fringe centers within circular grating moiré patterns. This ANN approach aims to mimic human decision making by eliminating complex mathematical computations or time-consuming image processing algorithms in moiré fringe recognition. A feed-forward backpropagation ANN architecture was adopted in this work. Parametric studies were performed to optimize the ANN architecture. The finalized ANN approach was able to determine the location of the fringe centers with average deviations of 3.167 pixels out of 200 pixels (≈1.6%) and 6.166 pixels out of 200 pixels (≈3.1%) for real moiré patterns that lie within and outside the training intervals, respectively. In addition, a reduction of 43.4% in the computational time was reported using the ANN approach. Finally, the applicability of the ANN approach for moiré fringe center determination was confirmed.

  20. Additive-subtractive phase-modulated electronic speckle interferometry: analysis of fringe visibility.

    PubMed

    Pouet, B F; Krishnaswamy, S

    1994-10-01

    Fringe-visibility issues of additive-subtractive phase-modulated (ASPM) electronic speckle pattern interferometry (ESPI) are explored. ASPM ESPI is a three-step method in which additive-speckle images are acquired rapidly in an analog fashion in every frame of a video sequence, a speckle phase modulation is intentionally introduced between frames, and a digital subtraction of consecutive pairs of additive-speckle images is performed. We show that this scheme has the good high-frequency noise immunity associated with additive-ESPI techniques as well as the good fringe visibility associated with subtractive-ESPI techniques. The method has better fringe visibility than can be obtained with purely additive ESPI and also does not suffer from the fringe distortions that can occur with subtractive ESPI in the presence of high-frequency noise. We show that even if full speckle decorrelation were to occur between the two additive speckle images that are to be subtracted, the visibility of ASPM ESPI fringes can be made to approach unity by suitable adjustment of the reference-to-object beam-intensity ratio.

  1. Defining western prairie fringed orchid (Platanthera praeclara) habitat

    NASA Astrophysics Data System (ADS)

    Knudson, Michael David

    Terrestrial orchids are at the forefront of the discussion about anthropogenically-driven extinction with more species threatened globally than any other plant family, mostly because of loss of habitat. The Western Prairie Fringed Orchid ( Platanthera praeclara) is a threatened species found on the Sheyenne National Grassland in southeast North Dakota, USA. This conservation area that is a vital refuge for this species is subject to management for multiple uses including livestock grazing and recreation. Orchids are subject to continuous monitoring, but knowledge of the relationship between landscape indicators and orchid locations is limited. Research is needed to provide a greater understanding of the landscape relative to orchid habitat to develop conservation management strategies suited to dealing with threats arising from future interactions between land management and use, and climate change. The spatial distribution of orchid habitat was defined using a suite of indicators that characterize topography, moisture, and vegetation cover and compared with orchid point-based field observations. High resolution infrared imagery, a LiDAR-derived DEM, and well observations were used to characterize landscape properties. The NDVI (a measure of vegetation cover), the Topographic Wetness Index (TWI: a measure of moisture on the landscape), the Topographic Position Index (TPI: a measure of position on the landscape), and the depth to groundwater (a measure of the depth from the land surface to the groundwater surface) provided the best set of indicators of orchid habitat. Comparison between orchid locations and landscape indicators identified orchid metrics (+/-2 sigma) used to classify landscape indicators which were combined to create orchid habitat maps. This study supports that distribution of orchid habitat are influenced by the selected landscape indicators, each providing important information to the analysis. Comparison of orchid metrics with groundwater

  2. Modeling of imaging fiber bundles and adapted signal processing for fringe projection

    NASA Astrophysics Data System (ADS)

    Matthias, Steffen; Kästner, Markus; Reithmeier, Eduard

    2016-12-01

    Fringe projection profilometry is an established technique for capturing three-dimensional (3-D)-geometry data with high-point densities in short time. By combining fringe projection with endoscopy techniques, it is possible to perform inline inspection of industrial manufacturing processes. A new fringe projection system is presented, which uses flexible image fiber bundles to achieve versatile positioning of a compact sensor head. When measuring specimens with highly varying reflectivity, such as technical surfaces on tool geometries, measurement errors increase especially due to the crosstalk between individual fibers in the bundle. A detailed analysis of the transmission properties of the utilized fiber bundles is presented. It is shown that aliasing is avoided due to the non-regular grid structure of a bundle. Different techniques are demonstrated to reduce the effect of crosstalk on the phase evaluation. Measurements of highly reflective technical surfaces with different geometrical properties are shown.

  3. Three-dimensional displacement measurement by fringe projection and speckle photography

    NASA Astrophysics Data System (ADS)

    Barrientos, B.; Cerca, M.; García-Márquez, J.; Hernández-Bernal, C.

    2008-04-01

    3D displacement fields are measured by the combination of two optical methods, fringe projection and speckle photography. The use of only one camera recording the necessary information implies that no calibration procedures are necessary as is the case in techniques based on stereoscopy. The out-of-plane displacement is measured by fringe projection whereas speckle photography yields the 2-D in-plane component. To show the feasibility of the technique, we analyze a detailed morphological spatio-temporal evolution of a model of the Earth's crust while subjected to compression forces. The results show that the combination of fringe projection and speckle photography is well suited for this type of studies.

  4. Observation of speckle pattern and interference fringe forks in stimulated Raman scattering beam profile

    NASA Astrophysics Data System (ADS)

    Drampyan, Raphael K.

    2001-05-01

    The circularly distributed speckle pattern, as well as interference fringe structure in profile of the beam of stimulated Raman scattering (SRS) I Stokes component, pumped by multimode radiation with nearly four-fold azimuthal symmetry, have been observed. The SRS was excited near the threshold of generation by nanosecond pulses of laser radiation at wavelength 530 nm. The profile of output pump beam had a uniform intensity distribution, whereas the SRS beam profile showed kaleidoscopic change from shot to shot, while the energies of input pulses were kept stable. The interference fringes showed a number of points where the fringes originated or vanished. Such behavior, which is the vortex signature, allows to suppose that SRS waves, generated from quantum noise, carry screw dislocations.

  5. Statistical generalized phase-shifting digital holography with a continuous fringe-scanning scheme.

    PubMed

    Yoshikawa, Nobukazu; Kajihara, Kazuki

    2015-07-01

    We propose a novel statistical generalized phase-shifting digital holography using a continuous fringe-scanning scheme. In this method, the continuous fringe-scanning scheme is implemented using a PC-based measurement system without any synchronous circuit between the digital camera and the phase shifter. Thus, nonuniformly phase-shifted interference fringes are captured sequentially because of the fluctuation of the image-capturing interval. To cope with the nonuniform phase shifts, we employ a statistical generalized phase-shifting approach. Since the algorithm is designed to use an arbitrary phase shift, the nonuniform phase shifts do not obstruct object wave retrieval. Simulations and experiments demonstrate that the proposed method can be used to implement a practical and accurate digital holography system.

  6. Fringing field suppression for liquid crystal gratings using equivalent capacitance configuration

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Xia, Jun; Zhang, Xiaobing; Xie, Yi; Kang, Mingwu; Zhang, Qiuzhi

    2014-10-01

    A liquid crystal grating with high spatial frequency and equivalent capacitance configuration is proposed, where two layers of periodical ground electrodes are interlaced and aligned with the addressing electrodes. The equivalent capacitance configuration can reduce the fringing field effect efficiently owing to the generated electric field resisting the fringing field and redistributing the equivalent voltage exerting on the liquid crystal layer. The phase modulation depth and far-field diffraction patterns both for conventional and novel configurations were simulated. The results show that phase modulation is greatly enhanced and the maximum diffraction efficiency for a sinusoidal phase grating is 33.86%, which indicates that the equivalent capacitance configuration provides a good solution for suppressing the fringing field effect.

  7. An endoscopic optical system for inner cylindrical measurement using fringe projection

    NASA Astrophysics Data System (ADS)

    Albertazzi G., Armando, Jr.; Hofmann, Allan C.; Fantin, Analucia V.; Santos, João M. C.

    2008-09-01

    This paper presents an endoscopic optical system to measure 3D shapes of inner cylindrical surfaces that combines photogrammetry and fringe projection. The device has two identical cameras aligned with the optical axis and facing each other, two conical lenses and one 360° helical fringe projector. The helical fringe pattern is projected in the inner surface to be measured, phase shifted and acquired by both cameras. The phase patterns are used to identify corresponding points and to reconstruct the surface in a regular cylindrical mesh using an alternative approach. A prototype was built, calibrated and tested. The paper presents the results and an application to inspect internal welding seams in 150 mm (6") diameter pipelines.

  8. The Fringe-Imaging Skin Friction Technique PC Application User's Manual

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory G.

    1999-01-01

    A personal computer application (CXWIN4G) has been written which greatly simplifies the task of extracting skin friction measurements from interferograms of oil flows on the surface of wind tunnel models. Images are first calibrated, using a novel approach to one-camera photogrammetry, to obtain accurate spatial information on surfaces with curvature. As part of the image calibration process, an auxiliary file containing the wind tunnel model geometry is used in conjunction with a two-dimensional direct linear transformation to relate the image plane to the physical (model) coordinates. The application then applies a nonlinear regression model to accurately determine the fringe spacing from interferometric intensity records as required by the Fringe Imaging Skin Friction (FISF) technique. The skin friction is found through application of a simple expression that makes use of lubrication theory to relate fringe spacing to skin friction.

  9. Three-dimensional displacement measurement by fringe projection and speckle photography

    SciTech Connect

    Barrientos, B.; Garcia-Marquez, J.; Cerca, M.; Hernandez-Bernal, C.

    2008-04-15

    3D displacement fields are measured by the combination of two optical methods, fringe projection and speckle photography. The use of only one camera recording the necessary information implies that no calibration procedures are necessary as is the case in techniques based on stereoscopy. The out-of-plane displacement is measured by fringe projection whereas speckle photography yields the 2-D in-plane component. To show the feasibility of the technique, we analyze a detailed morphological spatio-temporal evolution of a model of the Earth's crust while subjected to compression forces. The results show that the combination of fringe projection and speckle photography is well suited for this type of studies.

  10. Simulation method for interference fringe patterns in measuring gear tooth flanks by laser interferometry.

    PubMed

    Fang, Suping; Wang, Leijie; Komori, Masaharu; Kubo, Aizoh

    2010-11-20

    We present a ray-tracing-based method for simulation of interference fringe patterns (IFPs) for measuring gear tooth flanks with a two-path interferometer. This simulation method involves two steps. In the first step, the profile of an IFP is achieved by means of ray tracing within the object path of the interferometer. In the second step, the profile of an IFP is filled with interference fringes, according to a set of functions from an optical path length to a fringe gray level. To examine the correctness of this simulation method, simulations are performed for two spur involute gears, and the simulated IFPs are verified by experiments using the actual two-path interferometer built on an optical platform.

  11. Simple and accurate empirical absolute volume calibration of a multi-sensor fringe projection system

    NASA Astrophysics Data System (ADS)

    Gdeisat, Munther; Qudeisat, Mohammad; AlSa`d, Mohammed; Burton, David; Lilley, Francis; Ammous, Marwan M. M.

    2016-05-01

    This paper suggests a novel absolute empirical calibration method for a multi-sensor fringe projection system. The optical setup of the projector-camera sensor can be arbitrary. The term absolute calibration here means that the centre of the three dimensional coordinates in the resultant calibrated volume coincides with a preset centre to the three-dimensional real-world coordinate system. The use of a zero-phase fringe marking spot is proposed to increase depth calibration accuracy, where the spot centre is determined with sub-pixel accuracy. Also, a new method is proposed for transversal calibration. Depth and transversal calibration methods have been tested using both single sensor and three-sensor fringe projection systems. The standard deviation of the error produced by this system is 0.25 mm. The calibrated volume produced by this method is 400 mm×400 mm×140 mm.

  12. Eukaryotic expression, purification, crystallization and preliminary X-ray analysis of murine Manic Fringe

    SciTech Connect

    Jinek, Martin; Conti, Elena

    2006-08-01

    The catalytic domain of the murine glycosyltransferase Manic Fringe was expressed in insect cells. Removal by site-directed mutagenesis of two N-glycosylation sites present in the protein was essential to obtain crystals that diffracted to 1.8 Å resolution. Fringe proteins are Golgi-resident β1,3-N-acetylglucosaminyltransferases that regulate development in metazoa through glycosylation of the Notch receptor and its ligands. The catalytic domain of murine Manic Fringe was expressed in the baculovirus/insect-cell system as a secreted protein. Mass-spectrometric analysis of the purified protein indicated the presence of two N-linked glycans. Abolishing the glycosylation sites by site-directed mutagenesis was necessary in order to obtain orthorhombic crystals that diffracted to 1.8 Å resolution. For phasing, a highly redundant data set was collected using a crystal soaked with halide salts.

  13. The theoretical basis of the moiré fringe signal quality detecting by observing the figures

    NASA Astrophysics Data System (ADS)

    Yi, Jie; An, Li-min; Liu, Chun-xia

    2011-08-01

    The moiré fringe signal quality decides the precision of the encoder. In the production process of RESR, usually, the moiré fringe signal quality is detected by the Lissajou graphs observing by the oscilloscope. Lissajou graph is the common method for analyzing the dc level of two analog signals, the amplitude of alternating current, the phase of signal, the relation of frequencies and other parameters. It is convenient, intuitive, and would not be affected by the rate; furthermore, it applies to be used for field detection. The ideal moiré fringe signal has two sine signals which phase difference is 90°, and prefect round Lissajou graph. However, in practice, for a variety of factors, moiré fringe photoelectric signal has dc level, higher harmonic, orthogonality deviation, equal amplitude deviation, and so on; that is why Lissajou graph will appear offset or distortion. So we can observe the shape's deviation of the Lissajou graph in order to judge the signal deviations. This paper introduces the diameter deviation to describe deviation between the Lissajou graph of actual signal and the Lissajou graph of ideal signal, establishes the mathematical model of diameter deviation, and theoretically analyzes the relationship between the diameter deviation and the parameters of moiré fringe photoelectric signal. Using the VB6.0 simulation software to prove the results of the theoretical analysis, we find that the simulation results agree with the previous detection, which supply theoretical foundation for the observation of Lissajou graph. After analyzing the character of the encoder's signal when the encoder works in a uniformly accelerated motion, we point out the applicative conditions of the observation of Lissajou graph detecting moiré fringe signal. The conclusions of this paper have important significance for detecting the signal quality of encoder, and have certain reference value for detecting other signals.

  14. Fringe-controlled biodegradation under dynamic conditions: quasi 2-D flow-through experiments and reactive-transport modeling.

    PubMed

    Eckert, Dominik; Kürzinger, Petra; Bauer, Robert; Griebler, Christian; Cirpka, Olaf A

    2015-01-01

    Biodegradation in contaminated aquifers has been shown to be most pronounced at the fringe of contaminant plumes, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. While physical mixing of contaminant and electron acceptor by transverse dispersion has been shown to be the major bottleneck for biodegradation in steady-state plumes, so far little is known on the effect of flow and transport dynamics (caused, e.g., by a seasonally fluctuating groundwater table) on biodegradation in these systems. Towards this end we performed experiments in quasi-two-dimensional flow-through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth, also maintenance and dormancy are important processes that affect biodegradation performance under transient environmental conditions and therefore deserve increased consideration in future reactive-transport modeling.

  15. Evaluation of groundwater pollution potential of sewage-irrigated vegetable growing areas of the eastern fringe of Calcutta city.

    PubMed

    Mitra, A; Gupta, S K

    2000-01-01

    In recent years recycling in agriculture is a common method of disposal or utilisation of waste. However, recycling of wastes may cause contamination of groundwater by toxic elements like heavy metals, cationic and anionic contaminants and pathogens. Groundwater of shallow and deep tubewells was collected during 1991 to 1997 from raw sewage effluent irrigated garbage farming areas on the eastern fringe of Calcutta city. In general raw sewage effluents, sludges and sewage-irrigated soils contain very high amounts of cations, anions, organics and heavy metals. It is found that most of the groundwater contained undesirable pH, total dissolved solids, total hardness, calcium, magnesium, phenolic compounds, iron and manganese and the observed values or concentrations were much above the maximum desirable limits specified by World Health Organisation (WHO) and Bureau of Indian Standards (BIS) for use as drinking water. Groundwater of that area may be used for irrigation. Dispersion by leaching of the metals, cationic and anionic contaminants from irrigated soil and from settled bottom sludge in unlined sewage channels are the principal causes of groundwater contamination. Some management plans have been suggested to control further deterioration of groundwater quality.

  16. Periodic ice banding in freezing colloidal dispersions.

    PubMed

    Anderson, Anthony M; Worster, M Grae

    2012-12-04

    Concentrated colloidal alumina dispersions were frozen in a directional solidification apparatus that provides independent control of the freezing rate and temperature gradient. Two distinct steady-state modes of periodic ice banding were observed in the range of freezing rates examined. For each mode, the wavelength between successive bands of segregated ice decreases with increasing freezing rate. At low freezing rates (0.25-3 μm s(-1)), the ice segregates from the suspension into ice lenses, which are cracklike in appearance, and there is visible structure in the layer of rejected particles in the unfrozen region ahead of the ice lenses. In this regime, we argue that compressive cryosuction forces lead to the irreversible aggregation of the rejected particles into a close-packed cohesive layer. The temperature in the aggregated layer is depressed below the bulk freezing point by more than 2 °C before the ice lenses are encountered; moreover, this undercooled region appears as a light-colored layer. The magnitude of the undercooling and the color change in this region both suggest the presence of pore ice and the formation of a frozen fringe. The possibility of a frozen fringe is supported by a quantitative model of the freezing behavior. At intermediate freezing rates, around 4 μm s(-1), the pattern of ice segregation is disordered, coinciding with the disappearance of the dark- and light-colored layers. Finally, at high freezing rates (5-10 μm s(-1)), there is a new mode of periodic ice banding that is no longer cracklike and is absent of any visible structure in the suspension ahead of the ice bands. We discuss the implications of our experimental findings for theories of ice lensing.

  17. Real-time detection and elimination of nonorthogonality error in interference fringe processing

    SciTech Connect

    Hu Haijiang; Zhang Fengdeng

    2011-05-20

    In the measurement system of interference fringe, the nonorthogonality error is a main error source that influences the precision and accuracy of the measurement system. The detection and elimination of the error has been an important target. A novel method that only uses the cross-zero detection and the counting is proposed to detect and eliminate the nonorthogonality error in real time. This method can be simply realized by means of the digital logic device, because it does not invoke trigonometric functions and inverse trigonometric functions. And it can be widely used in the bidirectional subdivision systems of a Moire fringe and other optical instruments.

  18. Threshold voltage model of junctionless cylindrical surrounding gate MOSFETs including fringing field effects

    NASA Astrophysics Data System (ADS)

    Gupta, Santosh Kumar

    2015-12-01

    2D Analytical model of the body center potential (BCP) in short channel junctionless Cylindrical Surrounding Gate (JLCSG) MOSFETs is developed using evanescent mode analysis (EMA). This model also incorporates the gate bias dependent inner and outer fringing capacitances due to the gate-source/drain fringing fields. The developed model provides results in good agreement with simulated results for variations of different physical parameters of JLCSG MOSFET viz. gate length, channel radius, doping concentration, and oxide thickness. Using the BCP, an analytical model for the threshold voltage has been derived and validated against results obtained from 3D device simulator.

  19. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms.

    PubMed

    Volkov, V V; Han, M G; Zhu, Y

    2013-11-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice.

  20. Wide-band acousto-optic deflectors with high efficiency for visible range fringe pattern projector.

    PubMed

    Dupont, S; Kastelik, J C; Causa, F

    2007-10-01

    A laser fringe projection system based on a pair of identical acousto-optic TeO(2) deflectors operated at the same frequency and using tangential phase matching anisotropic interaction is demonstrated, achieving large bandwidth and high efficiency. A 40 MHz bandwidth and an acousto-optic efficiency higher than 60% have been measured at wavelength of 514 nm. The specific pris-matic configuration of the in-house developed deflectors greatly facilitates optical alignment of the instrument. The spatial period of the interference fringes can be dynamically controlled over almost one decade by tuning the frequency of the acoustic carriers.

  1. Automatic Fringe Detection for Oil Film Interferometry Measurement of Skin Friction

    NASA Technical Reports Server (NTRS)

    Naughton, Jonathan W.; Decker, Robert K.; Jafari, Farhad

    2001-01-01

    This report summarizes two years of work on investigating algorithms for automatically detecting fringe patterns in images acquired using oil-drop interferometry for the determination of skin friction. Several different analysis methods were tested, and a combination of a windowed Fourier transform followed by a correlation was found to be most effective. The implementation of this method is discussed and details of the process are described. The results indicate that this method shows promise for automating the fringe detection process, but further testing is required.

  2. Real-time detection and elimination of nonorthogonality error in interference fringe processing.

    PubMed

    Hu, Haijiang; Zhang, Fengdeng

    2011-05-20

    In the measurement system of interference fringe, the nonorthogonality error is a main error source that influences the precision and accuracy of the measurement system. The detection and elimination of the error has been an important target. A novel method that only uses the cross-zero detection and the counting is proposed to detect and eliminate the nonorthogonality error in real time. This method can be simply realized by means of the digital logic device, because it does not invoke trigonometric functions and inverse trigonometric functions. And it can be widely used in the bidirectional subdivision systems of a Moiré fringe and other optical instruments.

  3. Integrated particles sensor formed on single substrate using fringes formed by diffractive elements

    NASA Technical Reports Server (NTRS)

    Gharib, Morteza (Inventor); Fourguette, Dominique (Inventor); Modarress, Darius (Inventor); Taugwalder, Frederic (Inventor); Forouhar, Siamak (Inventor)

    2005-01-01

    Integrated sensors are described using lasers on substrates. In one embodiment, a first sensor forms a laser beam and uses a quartz substrate to sense particle motion by interference of the particles with a diffraction beam caused by a laser beam. A second sensor uses gradings to produce an interference. In another embodiment, an integrated sensor includes a laser element, producing a diverging beam, and a single substrate which includes a first diffractive optical element placed to receive the diverging beam and produce a fringe based thereon, a scattering element which scatters said fringe beam based on particles being detected, and a second diffractive element receiving scattered light.

  4. Highly dispersive slot waveguides.

    PubMed

    Zhang, Lin; Yue, Yang; Xiao-Li, Yinying; Beausoleil, Raymond G; Willner, Alan E

    2009-04-27

    We propose a slot-waveguide with high dispersion, in which a slot waveguide is coupled to a strip waveguide. A negative dispersion of up to -181520 ps/nm/km is obtained due to a strong interaction of the slot and strip modes. A flat and large dispersion is achievable by cascading the dispersive slot-waveguides with varied waveguide thickness or width for dispersion compensation and signal processing applications. We show - 31300 ps/nm/km dispersion over 147-nm bandwidth with <1% variance.

  5. SMED - Sulphur MEditerranean Dispersion

    NASA Astrophysics Data System (ADS)

    Salerno, Giuseppe G.; Sellitto, Pasquale; Corradini, Stefano; Di Sarra, Alcide Giorgio; Merucci, Luca; Caltabiano, Tommaso; La Spina, Alessandro

    2016-04-01

    Emissions of volcanic gases and particles can have profound impacts on terrestrial environment, atmospheric composition, climate forcing, and then on human health at various temporal and spatial scales. Volcanic emissions have been identified as one of the largest sources of uncertainty in our understanding of recent climate change trends. In particular, a primary role is acted by sulphur dioxide emission due to its conversion to volcanic sulphate aerosol via atmospheric oxidation. Aerosols may play a key role in the radiative budget and then in photochemistry and tropospheric composition. Mt. Etna is one of the most prodigious and persistent emitters of gasses and particles on Earth, accounting for about 10% of global average volcanic emission of CO2 and SO2. Its sulphur emissions stand for 0.7 × 106 t S/yr9 and then about 10 times bigger than anthropogenic sulphur emissions in the Mediterranean area. Centrepiece of the SMED project is to advance the understanding of volcanogenic sulphur dioxide and sulphate aerosol particles dispersion and radiative impact on the downwind Mediterranean region by an integrated approach between ground- and space-based observations and modelling. Research is addressed by exploring the potential relationship between proximal SO2 flux and aerosol measured remotely in the volcanic plume of Mt. Etna between 2000 and 2014 and distal aerosol ground-based measurements in Lampedusa, Greece, and Malta from AERONET network. Ground data are combined with satellite multispectral polar and geostationary imagers able to detect and retrieve volcanic ash and SO2. The high repetition time of SEVIRI (15 minutes) will ensure the potential opportunity to follow the entire evolution of the volcanic cloud, while, the higher spatial resolution of MODIS (1x1 km2), are exploited for investigating the probability to retrieve volcanic SO2 abundances from passive degassing. Ground and space observations are complemented with atmospheric Lagrangian model

  6. Resolving fringe ambiguities of a wide-field Michelson interferometer using visibility measurements of a noncollimated laser beam.

    PubMed

    Wan, Xiaoke; Wang, Ji; Ge, Jian

    2009-09-10

    An actively stabilized interferometer with a constant optical path difference is a key element in long-term astronomical observation, and resolving interference fringe ambiguities is important to produce high-precision results for the long term. We report a simple and reliable method of resolving fringe ambiguities of a wide-field Michelson interferometer by measuring the interference visibility of a noncollimated single-frequency laser beam. Theoretical analysis shows that the interference visibility is sensitive to a subfringe phase shift, and a wide range of beam arrangements is suitable for real implementation. In an experimental demonstration, a Michelson interferometer has an optical path difference of 7 mm and a converging monitoring beam has a numerical aperture of 0.045 with an incidental angle of 17 degrees. The resolution of visibility measurements corresponds to approximately 1/16 fringe in the interferometer phase shift. The fringe ambiguity-free region is extended over a range of approximately 100 fringes.

  7. Removing harmonic distortion of measurements of a defocusing three-step phase-shifting digital fringe projection system

    NASA Astrophysics Data System (ADS)

    XU, Zi-Xin; Chan, Yuk-Hee

    2017-03-01

    Binary defocusing method was adopted in 3D profilometry as it allows real-time measurement and does not need to handle the luminance nonlinearity of a projector. Current patch-based binary fringe patterns are periodic and carry strong harmonic distortion as compared with the ideal sinusoidal fringe patterns, which affects the measuring performance remarkably. In this paper, we propose a framework for generating aperiodic fringe patterns based on optimized patches. The produced fringe patterns can significantly lower the noise floor and suppress the harmonic distortion in the constructed phase map. Accordingly, the achieved depth measuring performance can be significantly improved. Special care is also taken during the optimization of the patches in our framework such that the depth measuring performance is robust to fringe period and defocusing extent.

  8. Ancient mitochondrial DNA from the northern fringe of the Neolithic farming expansion in Europe sheds light on the dispersion process

    PubMed Central

    Malmström, Helena; Linderholm, Anna; Skoglund, Pontus; Storå, Jan; Sjödin, Per; Gilbert, M. Thomas P.; Holmlund, Gunilla; Willerslev, Eske; Jakobsson, Mattias; Lidén, Kerstin; Götherström, Anders

    2015-01-01

    The European Neolithization process started around 12 000 years ago in the Near East. The introduction of agriculture spread north and west throughout Europe and a key question has been if this was brought about by migrating individuals, by an exchange of ideas or a by a mixture of these. The earliest farming evidence in Scandinavia is found within the Funnel Beaker Culture complex (Trichterbecherkultur, TRB) which represents the northernmost extension of Neolithic farmers in Europe. The TRB coexisted for almost a millennium with hunter–gatherers of the Pitted Ware Cultural complex (PWC). If migration was a substantial part of the Neolithization, even the northerly TRB community would display a closer genetic affinity to other farmer populations than to hunter–gatherer populations. We deep-sequenced the mitochondrial hypervariable region 1 from seven farmers (six TRB and one Battle Axe complex, BAC) and 13 hunter–gatherers (PWC) and authenticated the sequences using postmortem DNA damage patterns. A comparison with 124 previously published sequences from prehistoric Europe shows that the TRB individuals share a close affinity to Central European farmer populations, and that they are distinct from hunter–gatherer groups, including the geographically close and partially contemporary PWC that show a close affinity to the European Mesolithic hunter–gatherers. PMID:25487325

  9. Ancient mitochondrial DNA from the northern fringe of the Neolithic farming expansion in Europe sheds light on the dispersion process.

    PubMed

    Malmström, Helena; Linderholm, Anna; Skoglund, Pontus; Storå, Jan; Sjödin, Per; Gilbert, M Thomas P; Holmlund, Gunilla; Willerslev, Eske; Jakobsson, Mattias; Lidén, Kerstin; Götherström, Anders

    2015-01-19

    The European Neolithization process started around 12 000 years ago in the Near East. The introduction of agriculture spread north and west throughout Europe and a key question has been if this was brought about by migrating individuals, by an exchange of ideas or a by a mixture of these. The earliest farming evidence in Scandinavia is found within the Funnel Beaker Culture complex (Trichterbecherkultur, TRB) which represents the northernmost extension of Neolithic farmers in Europe. The TRB coexisted for almost a millennium with hunter-gatherers of the Pitted Ware Cultural complex (PWC). If migration was a substantial part of the Neolithization, even the northerly TRB community would display a closer genetic affinity to other farmer populations than to hunter-gatherer populations. We deep-sequenced the mitochondrial hypervariable region 1 from seven farmers (six TRB and one Battle Axe complex, BAC) and 13 hunter-gatherers (PWC) and authenticated the sequences using postmortem DNA damage patterns. A comparison with 124 previously published sequences from prehistoric Europe shows that the TRB individuals share a close affinity to Central European farmer populations, and that they are distinct from hunter-gatherer groups, including the geographically close and partially contemporary PWC that show a close affinity to the European Mesolithic hunter-gatherers.

  10. Lectures on Dispersion Theory

    DOE R&D Accomplishments Database

    Salam, A.

    1956-04-01

    Lectures with mathematical analysis are given on Dispersion Theory and Causality and Dispersion Relations for Pion-nucleon Scattering. The appendix includes the S-matrix in terms of Heisenberg Operators. (F. S.)

  11. Salary Guides and Fringe Benefits for Non-Certified Personnel, 1972-73. Bulletin No. III.

    ERIC Educational Resources Information Center

    New Jersey School Boards Association, Trenton. Div. of Special Services.

    This bulletin lists salary guide and fringe benefit data for noncertified personnel in 162 of New Jersey's 604 school districts. The data provided are grouped according to (1) office and attendance personnel, (2) maintenance and operations personnel, (3) transportation personnel, and (4) cafeteria personnel. Each section reports the minimum and…

  12. 29 CFR 4.176 - Payment of fringe benefits to temporary and part-time employees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the holiday, would be due no holiday benefits for that week. (3) Holiday or vacation pay obligations... paying such employees a proportion of the holiday or vacation benefits due full-time employees based on... week (40 hours) paid vacation under the applicable fringe benefit determination, then the...

  13. 29 CFR 4.173 - Meeting requirements for vacation fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Meeting requirements for vacation fringe benefits. 4.173... benefits. (a) Determining length of service for vacation eligibility. It has been found that for many types... his liability for vacation benefits for those workers in his employ. If prospective contractors...

  14. 29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 1 2011-07-01 2011-07-01 false Contract specification of determined minimum wages and... of determined minimum wages and fringe benefits. (a) Any contract in excess of $2,500 shall contain, as an attachment, the applicable, currently effective wage determination specifying the minimum...

  15. 29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 1 2013-07-01 2013-07-01 false Contract specification of determined minimum wages and... of determined minimum wages and fringe benefits. (a) Any contract in excess of $2,500 shall contain, as an attachment, the applicable, currently effective wage determination specifying the minimum...

  16. 29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Contract specification of determined minimum wages and... of determined minimum wages and fringe benefits. (a) Any contract in excess of $2,500 shall contain, as an attachment, the applicable, currently effective wage determination specifying the minimum...

  17. 29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 1 2012-07-01 2012-07-01 false Contract specification of determined minimum wages and... of determined minimum wages and fringe benefits. (a) Any contract in excess of $2,500 shall contain, as an attachment, the applicable, currently effective wage determination specifying the minimum...

  18. 29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Contract specification of determined minimum wages and... of determined minimum wages and fringe benefits. (a) Any contract in excess of $2,500 shall contain, as an attachment, the applicable, currently effective wage determination specifying the minimum...

  19. Absolute height measurement of specular surfaces with modified active fringe reflection photogrammetry

    NASA Astrophysics Data System (ADS)

    Ren, Hongyu; Jiang, Xiangqian; Gao, Feng; Zhang, Zonghua

    2014-07-01

    Deflectometric methods have been studied for more than a decade for slope measurement of specular freeform surfaces through utilization of the deformation of a sample pattern after reflection from a tested sample surface. Usually, these approaches require two-directional fringe patterns to be projected on a LCD screen or ground glass and require slope integration, which leads to some complexity for the whole measuring process. This paper proposes a new mathematical measurement model for measuring topography information of freeform specular surfaces, which integrates a virtual reference specular surface into the method of active fringe reflection photogrammetry and presents a straight-forward relation between height of the tested surface and phase signals. This method only requires one direction of horizontal or vertical sinusoidal fringe patterns to be projected from a LCD screen, resulting in a significant reduction in capture time over established methods. Assuming the whole system has been precalibrated during the measurement process, the fringe patterns are captured separately via the virtual reference and detected freeform surfaces by a CCD camera. The reference phase can be solved according to the spatial geometric relation between the LCD screen and the CCD camera. The captured phases can be unwrapped with a heterodyne technique and optimum frequency selection method. Based on this calculated unwrapped-phase and that proposed mathematical model, absolute height of the inspected surface can be computed. Simulated and experimental results show that this methodology can conveniently calculate topography information for freeform and structured specular surfaces without integration and reconstruction processes.

  20. New approach for identifying the zero-order fringe in variable wavelength interferometry

    NASA Astrophysics Data System (ADS)

    Galas, Jacek; Litwin, Dariusz; Daszkiewicz, Marek

    2016-12-01

    The family of VAWI techniques (for transmitted and reflected light) is especially efficient for characterizing objects, when in the interference system the optical path difference exceeds a few wavelengths. The classical approach that consists in measuring the deflection of interference fringes fails because of strong edge effects. Broken continuity of interference fringes prevents from correct identification of the zero order fringe, which leads to significant errors. The family of these methods has been proposed originally by Professor Pluta in the 1980s but that time image processing facilities and computers were hardly available. Automated devices unfold a completely new approach to the classical measurement procedures. The Institute team has taken that new opportunity and transformed the technique into fully automated measurement devices offering commercial readiness of industry-grade quality. The method itself has been modified and new solutions and algorithms simultaneously have extended the field of application. This has concerned both construction aspects of the systems and software development in context of creating computerized instruments. The VAWI collection of instruments constitutes now the core of the Institute commercial offer. It is now practically applicable in industrial environment for measuring textile and optical fibers, strips of thin films, testing of wave plates and nonlinear affects in different materials. This paper describes new algorithms for identifying the zero order fringe, which increases the performance of the system as a whole and presents some examples of measurements of optical elements.

  1. Simultaneous estimation of unwrapped phase and phase derivative from a closed fringe pattern

    NASA Astrophysics Data System (ADS)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2016-12-01

    We propose a new approach for the direct estimation of the unwrapped phase from a single closed fringe pattern. The fringe analysis is performed along a given row/column at a time by approximating the phase with a weighted linear combination of linearly independent basis functions. Gaussian radial basis functions with equally distributed centers and a fixed variance are considered for the phase approximation. A state space model is defined with the weights of the basis functions as the state vector elements. Extended Kalman filter is effectively utilized for the accurate state estimation. A fringe density estimation based criteria is established to select whether the phase estimation is performed in a row by row or column by column manner. In the seed row/column decided based on this criteria, the optimal basis dimension is computed. The proposed method effectively renders itself in the simultaneous estimation of the phase and the phase derivative. The proposed phase modeling approach also allows us to successfully demodulate the low density fringe patterns. Simulation and experimental results validate the practical applicability of the proposed method.

  2. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Taxation of fringe benefits-1985 through 1988 (temporary). 1.61-2T Section 1.61-2T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Definition of Gross Income, Adjusted Gross Income, and Taxable Income §...

  3. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Taxation of fringe benefits-1985 through 1988 (temporary). 1.61-2T Section 1.61-2T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Definition of Gross Income, Adjusted Gross Income, and Taxable Income §...

  4. Comparison of phase recovery methods in spiral speckle pattern interferometry correlation fringes

    NASA Astrophysics Data System (ADS)

    Vadnjal, Ana Laura; Etchepareborda, Pablo; Bianchetti, Arturo; Veiras, Francisco E.; Federico, Alejandro; Kaufmann, Guillermo H.

    2016-05-01

    Spiral interferometry can be used as a solution to the problem of sign ambiguity presented in the conventional speckle pattern interferometric technique when the optical phase needs to be reconstructed from a single closed fringe system. Depressions and elevations of the topography corresponding to the object deformation are distinguished by the direction of rotation of the local spiral fringe pattern. In this work, we implement and compare several methods for optical phase reconstruction by analyzing a single image composed of spiral speckle pattern interferometry correlation fringes. The implemented methods are based on contour line demodulation, center line demodulation, Spiral Phase Quadrature Transform and the 2D Riesz transform with multivector structure. Contour line and center line demodulation approaches are exclusively dedicated to images containing a fringe system with spiral structure. The others are based on the 2D Riesz transform, these being well known approaches in conventional interferometry. We examine simulated experiments and analyze some of the emerging drawbacks for solving the phase reconstruction problem by using different mean values of speckle size and background noise levels. We also discuss several numerical procedures that may well improve the efficiency and robustness of the presented numerical implementations. The performance of the implemented demodulation methods is evaluated by using a universal image quality index and therefore a quantitative comparison is also presented.

  5. High-speed digital color fringe projection technique for three-dimensional facial measurements

    NASA Astrophysics Data System (ADS)

    Liu, Cheng-Yang; Chang, Li-Jen; Wang, Chung-Yi

    2016-04-01

    Digital fringe projection techniques have been widely studied in industrial applications because of the advantages of high accuracy, fast acquisition and non-contact operation. In this study, a single-shot high-speed digital color fringe projection technique is proposed to measure three-dimensional (3-D) facial features. The light source used in the measurement system is structured light with color fringe patterns. A projector with digital light processing is used as light source to project color structured light onto face. The distorted fringe pattern image is captured by the 3-CCD color camera and encoded into red, green and blue channels. The phase-shifting algorithm and quality guided path unwrapping algorithm are used to calculate absolute phase map. The detecting angle of the color camera is adjusted by using a motorized stage. Finally, a complete 3-D facial feature is obtained by our technique. We have successfully achieved simultaneous 3-D phase acquisition, reconstruction and exhibition at a speed of 0.5 s. The experimental results may provide a novel, high accuracy and real-time 3-D shape measurement for facial recognition system.

  6. Salary Guides and Fringe Benefits for Non-Certified Personnel, 1972-73. Bulletin No. II.

    ERIC Educational Resources Information Center

    New Jersey School Boards Association, Trenton. Div. of Special Services.

    This bulletin lists salary guide and fringe benefit data for noncertified personnel in 155 of New Jersey's 604 school districts. The data provided in this bulletin are grouped according to (1) office personnel and attendance personnel, (2) maintenance and operations personnel, (3) transportation personnel, and (4) cafeteria personnel. Each section…

  7. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... maintenance of, and insurance for, the automobile. Neither an employer nor an employee may reduce the Annual... items. Examples of fringe benefits include: an employer-provided automobile, a flight on an employer... the first person is considered use by the second person. For example, provision of an automobile to...

  8. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... maintenance of, and insurance for, the automobile. Neither an employer nor an employee may reduce the Annual... items. Examples of fringe benefits include: an employer-provided automobile, a flight on an employer... the first person is considered use by the second person. For example, provision of an automobile to...

  9. Discontinuing Social Security: Reallocating Employer Funds to Improve Employer Fringe Benefit Plans.

    ERIC Educational Resources Information Center

    Marsee, Jeffrey A.

    Texarkana (Texas) Community College and Texarkana Independent School District left the federal Social Security System (SSS) and reallocated SSS funds to a self-administered fringe benefit program, while also returning employees' SSS contributions to them intact. Several safeguards for Texas employees were already in place through the Texas Teacher…

  10. Application of robust color composite fringe in flip-chip solder bump 3-D measurement

    NASA Astrophysics Data System (ADS)

    Kuo, Chung-Feng Jeffrey; Wu, Han-Cheng

    2017-04-01

    This study developed a 3-D measurement system based on flip-chip solder bump, used fringes with different modulation intensities in color channels, in order to produce color composite fringe with robustness, and proposed a multi-channel composite phase unwrapping algorithm, which uses fringe modulation weights of different channels to recombine the phase information for better measurement accuracy and stability. The experimental results showed that the average measurement accuracy is 0.43μm and the standard deviation is 1.38 μm. The results thus proved that the proposed 3-D measurement system is effective in measuring a plane with a height of 50 μm. In the flip-chip solder bump measuring experiment, different fringe modulation configurations were tested to overcome the problem of reflective coefficient between the flip-chip base board and the solder bump. The proposed system has a good measurement results and robust stability in the solder bump measurement, and can be used for the measurement of 3-D information for micron flip-chip solder bump application.

  11. Moire-Fringe Images of Twin Boundaries in Chemical Vapor Deposited Diamond

    DTIC Science & Technology

    1992-07-10

    Features in lattice image micrographs of chemical vapor deposited diamond can be interpreted as Moire fringes that occur when viewing twin boundaries that...are inclined to the electron beam. The periodicities in images of inclined twin boundaries with Sigma=3 and Sigma=9 misorientations have been modeled by computer graphic simulation.

  12. Accurate and flexible calibration technique for fringe projection profilometry by using encoded points and Fourier analysis

    NASA Astrophysics Data System (ADS)

    González, Andrés. L.; Contreras, Carlos R.; Meneses, Jaime E.

    2014-05-01

    In order to get measures with a high accurate, three-dimensional reconstruction systems are implemented in industrial, medical, and investigative fields. To obtain high accurate is necessary to carry out an appropriate calibration procedure. In fringe projection profilometry, this procedure allows obtaining a relation between absolute phase and three-dimensional (3D) information of the object in study; however, to execute such procedure a precise movement stage is required. A fringe projection system is formed by a projector, a digital camera and a control unit, called like a projection-acquisition unit in this paper. The calibration of the projection-acquisition unit consists in to establish the parameters that are required to transform the phase of the projected fringes to metric coordinates of the object surface. These parameters are a function of the intrinsic and extrinsic parameters of both camera and projector, due to the projector is modeled as an inverse camera. For this purpose, in this paper a novel and flexible calibration method that allows calibrating any device that works with fringe projection profilometry is proposed. In this method is used a reference plane placed in random positions and the projection of an encoded pattern of control points. The camera parameters are computed using Zhang's calibration method; and the projector parameters are computed from the camera parameters and the phase of the pattern of control points, which is determined by using Fourier analysis. Experimental results are presented to demonstrate the performance of the calibration method.

  13. Fringe proteins modulate Notch-ligand cis and trans interactions to specify signaling states

    PubMed Central

    LeBon, Lauren; Lee, Tom V; Sprinzak, David; Jafar-Nejad, Hamed; Elowitz, Michael B

    2014-01-01

    The Notch signaling pathway consists of multiple types of receptors and ligands, whose interactions can be tuned by Fringe glycosyltransferases. A major challenge is to determine how these components control the specificity and directionality of Notch signaling in developmental contexts. Here, we analyzed same-cell (cis) Notch-ligand interactions for Notch1, Dll1, and Jag1, and their dependence on Fringe protein expression in mammalian cells. We found that Dll1 and Jag1 can cis-inhibit Notch1, and Fringe proteins modulate these interactions in a way that parallels their effects on trans interactions. Fringe similarly modulated Notch-ligand cis interactions during Drosophila development. Based on these and previously identified interactions, we show how the design of the Notch signaling pathway leads to a restricted repertoire of signaling states that promote heterotypic signaling between distinct cell types, providing insight into the design principles of the Notch signaling system, and the specific developmental process of Drosophila dorsal-ventral boundary formation. DOI: http://dx.doi.org/10.7554/eLife.02950.001 PMID:25255098

  14. IN SITU ABIOTIC DETOXIFICATION AND IMMOBILIZATION OF HEXAVALENT CHROMIUM IN THE CAPILLARY FRINGE ZONE

    EPA Science Inventory

    Detailed site characterization data from the former electroplating shop at the U.S. Coast Guard Air Support Center, Elizabeth City, North Carolina suggested that the elevated Cr(VI) in the capillary fringe area had contaminated the ground water at the site. Most of the mobile Cr(...

  15. 26 CFR 1.162-25T - Deductions with respect to noncash fringe benefits (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Deductions with respect to noncash fringe... illustrate the provisions of this section. Example 1. On January 1, 1986, X Company owns and provides the use... percent of $5,600) in E's gross income for 1986. X may not deduct the amount included in E's income...

  16. Vortex-Airfoil Interaction and Application of Methods for Digital Fringe Analysis.

    DTIC Science & Technology

    1986-03-15

    Table of Contents 1. Introduction 1 2. A model for vortex paths around a profile and the sound generated by vortex-profile interaction 2"-- 3...I’ S.TTE(d~,t. TYPE OF PIrPORT a PERID COWERED ’. * Vortex-airfoil interaction and application of *methods for digital fringe analysis. 1 6

  17. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC... 1205; (2) The pilot exits the DC SFRA by the most direct route before proceeding on course; and (3) The... at a fringe airport or transit the DC SFRA unless that pilot complies with the DC SFRA...

  18. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC... 1205; (2) The pilot exits the DC SFRA by the most direct route before proceeding on course; and (3) The... at a fringe airport or transit the DC SFRA unless that pilot complies with the DC SFRA...

  19. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC... 1205; (2) The pilot exits the DC SFRA by the most direct route before proceeding on course; and (3) The... at a fringe airport or transit the DC SFRA unless that pilot complies with the DC SFRA...

  20. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC... 1205; (2) The pilot exits the DC SFRA by the most direct route before proceeding on course; and (3) The... at a fringe airport or transit the DC SFRA unless that pilot complies with the DC SFRA...

  1. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Washington, DC... 1205; (2) The pilot exits the DC SFRA by the most direct route before proceeding on course; and (3) The... at a fringe airport or transit the DC SFRA unless that pilot complies with the DC SFRA...

  2. Theoretical study of the properties of X-ray diffraction moiré fringes. I

    SciTech Connect

    Yoshimura, Jun-ichi

    2015-05-14

    A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory, where the effect of the Pendellösung intensity oscillation on the moiré pattern is explained in detail. A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997 ▸). Acta Cryst. A53, 810–812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect of Pendellösung intensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general.

  3. On the development of a low-cost rigid borescopic fringe projection system

    NASA Astrophysics Data System (ADS)

    Schlobohm, Jochen; Pösch, Andreas; Kästner, Markus; Reithmeier, Eduard

    2015-01-01

    Examining the geometry of complex industrial free form objects, like a blade integrated disk (blisk) of a jet engine compressor, is currently subject to research. High measurement precision and speed are required and the complex geometry poses a challenge for state of the art measurement systems. In order to fulfill typical inspection requirements, the fringe projection methodology was adapted in this work to accomplish the task of fast and precise geometry examination. A low cost borescopic fringe projection system for 3D shape measurement based on consumer electronics combined with state of the art optics was developed. Nevertheless, it is able to provide measurement uncertainties comparable to professional systems. We are using a portable consumer LED-beamer, which we have modified to fit the optics of the borescope and a Raspberry Pi single-board computer with a 5 megapixel camera to capture the fringe patterns. With this setup and fringe projection algorithms, which have been developed by this institute over the last years, we were able to perform high quality measurements while still being suitable for a compact inspection system. Measurements with high point densities are possible even in narrow areas of parts with complex geometries like blisks. The measuring system and first measurement results will be presented at the conference.

  4. Tangent least-squares fitting filtering method for electrical speckle pattern interferometry phase fringe patterns

    NASA Astrophysics Data System (ADS)

    Tang, Chen; Wang, Wenping; Yan, Haiqing; Gu, Xiaohui

    2007-05-01

    An efficient method is proposed to reduce the noise from electrical speckle pattern interferometry (ESPI) phase fringe patterns obtained by any technique. We establish the filtering windows along the tangent direction of phase fringe patterns. The x and y coordinates of each point in the established filtering windows are defined as the sine and cosine of the half-wrapped phase multiplied by a random quantity, then phase value is calculated using these points' coordinates based on a least-squares fitting algorithm. We tested the proposed methods on the computer-simulated speckle phase fringe patterns and the experimentally obtained phase fringe pattern, respectively, and compared them with the improved sine/cosine average filtering method [Opt. Commun. 162, 205 (1999)] and the least-squares phase-fitting method [Opt. Lett. 20, 931 (1995)], which may be the most efficient methods. In all cases, our results are even better than the ones obtained with the two methods. Our method can overcome the main disadvantages encountered by the two methods.

  5. Fringe jump analysis and electronic corrections for the Tore Supra far infrared interferometer.

    PubMed

    Gil, C; Barbuti, A; Elbèze, D; Pastor, P; Philip, J; Toulouse, L

    2008-10-01

    On the Tore Supra tokamak, the ten-channel far infrared interferometer consists of a double color (119 and 195 microm) system with two detectors for each channel to measure the plasma density. The phase measurement is obtained by combining a 100 kHz shifted reference beam with the probing beam that has crossed the plasma. The achieved precision--a few percent of a fringe--is very good compared with the expected variations due to plasma, which are on the order of several fringes. However, the counting of the fringe variations can be affected when the signal is perturbed by electromagnetic interferences or when it deviates in the presence of strong plasma refraction changes occurring during ICRH breakdowns, pellet injections, or disruptions. This induces a strong decrease in the reliability of the measurement, which is an important concern when the diagnostic is used for density control. We describe in this paper the renewing of the electronics that has been achieved to reduce and correct the number of the so-called fringe jumps. A new zero crossing method for phase measurement is used, together with a field programmable gate array semiconductor integration, to measure the phase and activate the algorithm of corrections every 10 micros. Comparisons between a numerical oscilloscope analysis and the corrected acquired data in the case of laboratory amplitude modulation tests and in the case of real plasma perturbations are also discussed.

  6. Links between fringe pattern analysis and digital image correlation: windowed, optimal, and tracking (WOT)

    NASA Astrophysics Data System (ADS)

    Qian, Kemao

    2014-07-01

    A windowed, optimal and tracking (WOT) strategy for measurement data analysis is described, explained and discussed. Many fringe pattern analysis and digital image correlation algorithms adopted this strategy, and thus their similarities and links are revealed. Although this strategy is not new, highlighting it is believed to be helpful for future algorithm development.

  7. Dispersion y dinamica poblacional

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dispersal behavior of fruit flies is appetitive. Measures of dispersion involve two different parameter: the maximum distance and the standard distance. Standard distance is a parameter that describes the probalility of dispersion and is mathematically equivalent to the standard deviation around ...

  8. Control bandwidth improvements in GRAVITY fringe tracker by switching to a synchronous real time computer architecture

    NASA Astrophysics Data System (ADS)

    Abuter, Roberto; Dembet, Roderick; Lacour, Sylvestre; di Lieto, Nicola; Woillez, Julien; Eisenhauer, Frank; Fedou, Pierre; Phan Duc, Than

    2016-08-01

    The new VLTI (Very Large Telescope Interferometer) 1 instrument GRAVITY5, 22, 23 is equipped with a fringe tracker16 able to stabilize the K-band fringes on six baselines at the same time. It has been designed to achieve a performance for average seeing conditions of a residual OPD (Optical Path Difference) lower than 300 nm with objects brighter than K = 10. The control loop implementing the tracking is composed of a four stage real time computer system compromising: a sensor where the detector pixels are read in and the OPD and GD (Group Delay) are calculated; a controller receiving the computed sensor quantities and producing commands for the piezo actuators; a concentrator which combines both the OPD commands with the real time tip/tilt corrections offloading them to the piezo actuator; and finally a Kalman15 parameter estimator. This last stage is used to monitor current measurements over a window of few seconds and estimate new values for the main Kalman15 control loop parameters. The hardware and software implementation of this design runs asynchronously and communicates the four computers for data transfer via the Reflective Memory Network3. With the purpose of improving the performance of the GRAVITY5, 23 fringe tracking16, 22 control loop, a deviation from the standard asynchronous communication mechanism has been proposed and implemented. This new scheme operates the four independent real time computers involved in the tracking loop synchronously using the Reflective Memory Interrupts2 as the coordination signal. This synchronous mechanism had the effect of reducing the total pure delay of the loop from 3.5 [ms] to 2.0 [ms] which then translates on a better stabilization of the fringes as the bandwidth of the system is substantially improved. This paper will explain in detail the real time architecture of the fringe tracker in both is synchronous and synchronous implementation. The achieved improvements on reducing the delay via this mechanism will be

  9. Dispersion in the Surfzone: Tracer Dispersion Studies

    DTIC Science & Technology

    2011-09-30

    objective is to improve understanding and modeling of dispersion of tracers (pol­ lution, fecal indicator bacteria, fine sediments) within the...discussed further here. Stochastic Particle Simulation for Surfzone Dispersion Drifter-derived diffusivities are time-dependent. In an unbounded...diffusion. Here HB06 particle trajectories are stochastically simulated with the Langevin equations with a shoreline boundary to explain the observed

  10. Theory of dispersive microlenses

    NASA Technical Reports Server (NTRS)

    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.

  11. Recovery of absolute phases for the fringe patterns of three selected wavelengths with improved anti-error capability

    NASA Astrophysics Data System (ADS)

    Long, Jiale; Xi, Jiangtao; Zhang, Jianmin; Zhu, Ming; Cheng, Wenqing; Li, Zhongwei; Shi, Yusheng

    2016-09-01

    In a recent published work, we proposed a technique to recover the absolute phase maps of fringe patterns with two selected fringe wavelengths. To achieve higher anti-error capability, the proposed method requires employing the fringe patterns with longer wavelengths; however, longer wavelength may lead to the degradation of the signal-to-noise ratio (SNR) in the surface measurement. In this paper, we propose a new approach to unwrap the phase maps from their wrapped versions based on the use of fringes with three different wavelengths which is characterized by improved anti-error capability and SNR. Therefore, while the previous method works on the two-phase maps obtained from six-step phase-shifting profilometry (PSP) (thus 12 fringe patterns are needed), the proposed technique performs very well on three-phase maps from three steps PSP, requiring only nine fringe patterns and hence more efficient. Moreover, the advantages of the two-wavelength method in simple implementation and flexibility in the use of fringe patterns are also reserved. Theoretical analysis and experiment results are presented to confirm the effectiveness of the proposed method.

  12. Detecting land-use/land-cover change in rural-urban fringe areas using extended change-vector analysis

    NASA Astrophysics Data System (ADS)

    He, Chunyang; Wei, Anni; Shi, Peijun; Zhang, Qiaofeng; Zhao, Yuanyuan

    2011-08-01

    Detecting land-use/land-cover (LULC) changes in rural-urban fringe areas (RUFAs) timely and accurately using satellite imagery is essential for land-use planning and management in China. Although traditional spectral-based change-vector analysis (CVA) can effectively detect LULC change in many cases, it encounters difficulties in RUFAs because of deficiencies in the spectral information of satellite images. To detect LULC changes in RUFAs effectively, this paper proposes an extended CVA approach that incorporates textural change information into the traditional spectral-based CVA. The extended CVA was applied to three different pilot RUFAs in China with different remotely sensed data, including Landsat Thematic Mapper (TM), China-Brazil Earth Resources Satellite (CBERS) and Advanced Land Observing Satellite (ALOS) images. The results demonstrated the improvement of the extended CVA compared to the traditional spectral-based CVA with the overall accuracy increased between 4.66% and 8.00% and the kappa coefficient increased between 0.10 and 0.15, respectively. The advantage of the extended CVA lies in its integration of both spectral and textural change information to detect LULC changes, allowing for effective discrimination of LULC changes that are spectrally similar but texturally different in RUFAs. The extended CVA has great potential to be widely used for LULC-change detection in RUFAs, which are often heterogeneous and fragmental in nature, with rich textural information.

  13. Cost-effective and full-field method for measuring vibration of loudspeaker membrane using fringe projection

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Li, Yong; Zhang, Zhiliang; Gao, Peng

    2014-11-01

    We proposed a cost-effective and full-field method for measuring vibration of loudspeaker using general industrial camera and fringe projection. The loudspeaker is excited by a sinusoidal signal. The fringe pattern is projected on the measured loudspeaker membrane that is dynamically deformed. Then the deformed fringes are captured by a camera. A trigger generation circuit is designed to control the camera. The Fourier Transform Profilometry (FTP) is adopted for 3D shape reconstruction. The validity of this method is approved by experiments. The cost of proposed measurement system is dramatically lower than that using high-speed camera.

  14. Analysis of the marriage and fertility survey of Yi minority women in the fringe areas of Liangshan Mountain.

    PubMed

    Pan, X; Wang, R; Zhang, P

    1991-01-01

    Based on data from a survey of 937 Yi women aged 15-64 years in Bianyuan on Liangshan Mountain in Malong and Gaoping Townships in China, this study compared the marriage and fertility characteristics of 1986 to those of 1982. The more closely the Yi live together, the worse their economic and health care conditions are due to their isolation from the outside world. These conditions are not conducive to the practice of birth control. The results show that married Yi women living in fringe areas have fewer live births than Yi women living on Liangshan Mountain. Child survival is similar in both areas. The Yi of Liangshan Mountain believe that high fertility is a necessary compensation for high mortality. Evidence from Yi in fringe areas may help dispel the fears of birth control and change beliefs about the balance between mortality and births. The Yi in fringe areas have better economic, cultural, and health care facilities. They exhibited a postponed mean age of first marriage, fewer early marriages, and lower mortality. Life expectancy was longer and fertility lower as a result of the birth control program operating in the fringe area. Fertility among the Yi women in Bianyuan is 19.85% among the unmarried, 75.46% among the married, 4.48% among the widowed, and .21% among the divorced. Fertility is higher for the married and unmarried but lower for the divorced or widowed than in fringe areas. A higher percentage of 15-19 years old and a lower percentage of 20-24 years olds are married in Liangshan Mountain. 80% of Yi women 20-24 years old who live in fringe areas are married. The mean age at marriage has been slowly rising, and until the 1980s, there was little significant difference between Yi women in fringe or mountain areas. There is as low rate of widowed and divorced women in fringe areas. The mean age of first birth has also risen over time. Liangshan Mountain fertility was 201.12/1000 for general fertility and 7.49993 for total fertility, while for fringe

  15. Formation of uniform fringe pattern free from diffraction noise at LDA measurement volume using holographic imaging configuration

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Nirala, A. K.

    2016-05-01

    In the present study we have proposed a technique for improving fringe quality at laser Doppler anemometry measurement volume in real time using single hololens imaging configuration over conventional imaging configuration with Gaussian beam optics. In order to remove interference fringe gradients as well as higher order diffraction noise formed at measurement volume in the former approach, a combined hololens imaging system has also been proposed. For qualitative as well as quantitative analysis of fringes formed at measurement volume, atomic force microscopy (AFM) analysis has been performed.

  16. The Trajectory of Dispersal Research in Conservation Biology. Systematic Review

    PubMed Central

    Driscoll, Don A.; Banks, Sam C.; Barton, Philip S.; Ikin, Karen; Lentini, Pia; Lindenmayer, David B.; Smith, Annabel L.; Berry, Laurence E.; Burns, Emma L.; Edworthy, Amanda; Evans, Maldwyn J.; Gibson, Rebecca; Heinsohn, Rob; Howland, Brett; Kay, Geoff; Munro, Nicola; Scheele, Ben C.; Stirnemann, Ingrid; Stojanovic, Dejan; Sweaney, Nici; Villaseñor, Nélida R.; Westgate, Martin J.

    2014-01-01

    decisions. Ambitious, multi-disciplinary research programs studying many species are critical for advancing dispersal research. PMID:24743447

  17. Impact of land-use change and hard structures on the evolution of fringing marsh shorelines

    NASA Astrophysics Data System (ADS)

    Mattheus, Christopher R.; Rodriguez, Antonio B.; McKee, Brent A.; Currin, Carolyn A.

    2010-07-01

    Estuarine fringe marshes provide essential ecosystem services to coastal regions, including carbon sequestration and provision of shelter and nursery grounds for aquatic and terrestrial animals. The ability of a marsh to sustain itself by vertical accretion in response to sea-level rise is, in part, limited by inorganic sediment supply. Models attempting to forecast salt-marsh response to future sea-level rise commonly ignore land-use changes, despite the recent coastal population boom and the potential of land-use changes to alter sediment sources and modify established sediment-transport pathways. This study investigates the impacts of landscape modifications, which are typical of coastal areas, on the nearshore sedimentation and edge evolution of two fringing marshes. The sites examined include a marsh fringing the upper bay and a marsh fringing a beach ridge on the estuarine shoreline of a barrier island. Both sites are located in the same estuarine system, have similar hydrologic settings and comparable vegetation densities. Previous work, marsh cores, and a historical record from aerial photos indicate that although the fringe marshes are in different geomorphic locations, prior to anthropogenic modifications they were similar in terms of nearshore-sediment composition, scarp-shoreline morphology, and shoreline trajectory. The upper-bay marsh was impacted by the introduction of tree farming in the watershed of a tributary creek to the upper bay, which increased upland erosion and caused higher sedimentation rates in the estuary. The back-barrier marsh, which received no contribution from the tree farm because it is distal with respect to river input, was modified by the installation of a pier and rock sill. Terrestrial LIDAR, surface elevation tables, and accretion rates obtained from radioisotope analyses show that the deforestation induced high rates of nearshore and marsh accretion at the upper-bay site, which is promoting marsh colonization and expansion

  18. Light-scattering and dispersion behavior of multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Saltiel, Craig; Manickavasagam, Siva; Pinar Mengüc, M.; Andrews, Rodney

    2005-08-01

    Elliptically polarized light-scattering measurements were performed to investigate the dispersion behavior of multiwalled carbon nanotubes (MWNT). Xylene- and pyridine-derived MWNT powders were dispersed in water and ethanol in separate optic cells and allowed to sit undisturbed over a two-week time period after probe sonication. Continuous light-scattering measurements taken between scattering angles of 10-170 deg and repeated over several days showed that the nanotubes formed fractal-like networks. The pyridine-derived MWNTs showed greater dispersion variation over time, tending to aggregate and clump much faster than the xylene-derived tubes. The water suspensions appeared much more stable than the ethanol suspensions, which transformed into nonfractal morphology after a few hours. We relate the dispersion stability to size and fringe patterns on the outer surface of the nanotubes. Measured values of fractal dimension were distinctly lower than those in previous studies of single-walled carbon nanotubes. Profiles of both diagonal and off-diagonal scattering matrix elements are presented.

  19. Dispersion management with metamaterials

    DOEpatents

    Tassin, Philippe; Koschny, Thomas; Soukoulis, Costas M.

    2017-03-07

    An apparatus, system, and method to counteract group velocity dispersion in fibers, or any other propagation of electromagnetic signals at any wavelength (microwave, terahertz, optical, etc.) in any other medium. A dispersion compensation step or device based on dispersion-engineered metamaterials is included and avoids the need of a long section of specialty fiber or the need for Bragg gratings (which have insertion loss).

  20. Dispersion in photonic crystals

    NASA Astrophysics Data System (ADS)

    Witzens, Jeremy

    2005-11-01

    Investigations on the dispersive properties of photonic crystals, modified scattering in ring-resonators, monolithic integration of vertical-cavity surface-emitting lasers and advanced data processing techniques for the finite-difference time-domain method are presented. Photonic crystals are periodic mesoscopic arrays of scatterers that modify the propagation properties of electromagnetic waves in a similar way as "natural" crystals modify the properties of electrons in solid-state physics. In this thesis photonic crystals are implemented as planar photonic crystals, i.e., optically thin semiconductor films with periodic arrays of holes etched into them, with a hole-to-hole spacing of the order of the wavelength of light in the dielectric media. Photonic crystals can feature forbidden frequency ranges (the band-gaps) in which light cannot propagate. Even though most work on photonic crystals has focused on these band-gaps for application such as confinement and guiding of light, this thesis focuses on the allowed frequency regions (the photonic bands) and investigates how the propagation of light is modified by the crystal lattice. In particular the guiding of light in bulk photonic crystals in the absence of lattice defects (the self-collimation effect) and the angular steering of light in photonic crystals (the superprism effect) are investigated. The latter is used to design a planar lightwave circuit for frequency domain demultiplexion. Difficulties such as efficient insertion of light into the crystal are resolved and previously predicted limitations on the resolution are circumvented. The demultiplexer is also fabricated and characterized. Monolithic integration of vertical-cavity surface-emitting lasers by means of resonantly enhanced grating couplers is investigated. The grating coupler is designed to bend light through a ninety-degree angle and is characterized with the finite-difference time-domain method. The vertical-cavity surface-emitting lasers are

  1. Modelling Infragravity Waves and Currents across a Fringing Reef: Ningaloo Reef, Western Australia

    NASA Astrophysics Data System (ADS)

    van Dongeren, A. R.; Duong Minh, T.; Lowe, R.; Roelvink, J.; Ranasinghe, R.; Symonds, G.

    2010-12-01

    The majority of the world’s coastlines contain submerged reef structures of various types, i.e. tropical coral reefs, relic temperate limestone platforms, and other submerged rock formations. Relatively little research has been conducted to study nearshore hydrodynamic processes that occur in reef environments. A good understanding of these processes is important because waves and wave-induced currents drive sediment transport, nutrient dynamics, and dispersal of larval coral and fish. Through the development of improved hydrodynamic models, the impact of environmental changes and human impacts on reefs may be accurately assessed. However, predictive models have historically been developed and tested using sandy coast environments. There are some important differences with reefs: wave breaking over the reef results in onshore flows with a higher bed friction coefficient, as well as set-up. Recent field studies (e.g., Lowe et al. JPO, 2009a) have shown the transformation of swell energy on reefs, and numerical model studies (Symonds and Black, JCR 2001, Ranasinghe et al., Coastal Eng. 2006, Lowe et al. J. Geoph. Res. 2009b) have shown that the spatial pattern of mean wave heights and mean currents can be qualitatively reproduced. However, the bulk of the measured variability is often in the infragravity frequency band (Pequignet et al. Geoph. Res. Lett., 2009 and Lowe et al., in prep.). The recently developed open-source model XBeach (Roelvink et al, Coastal Eng. 2009) is specifically designed to model these wave motions and associated sediment transport and has been successfully applied to sandy coasts (McCall et al., Coastal Eng. 2010). The objective of this paper is to apply XBeach to simulate infragravity forcing at Ningaloo Reef, a large fringing coral reef located along the northwest coastline of Western Australia. A field experiment at Ningaloo Reef (Western Australia) conducted in June 2009 by Lowe et al (in prep.) specifically aimed at measuring

  2. Center searching and tracking of circular interference fringes for precision measurement

    NASA Astrophysics Data System (ADS)

    Li, Yan; Qu, Shiliang; Qu, Jian; Luo, Zhiyong

    2012-02-01

    We report an algorithm for searching and tracking the center of the circular interference fringes. The algorithm was programmed by VB.NET for processing the interference images captured by CCD camera. Images were changed into binary gray-level format by the Otsu method. The circular scanning method was used to extract the outline of circular interference fringes, and then the coordinates of the perpendicular subtenses were used to remove noise pixels. Finally, the coordinate of the center was calculated by statistical method. The experimental results are in good agreement with the simulation images. The algorithm had subpixel accuracy and anti-noise ability. Thus, the algorithm can be used in accurate measurement for its automatic processing ability.

  3. Two-step fringe pattern analysis with a Gabor filter bank

    NASA Astrophysics Data System (ADS)

    Rivera, Mariano; Dalmau, Oscar; Gonzalez, Adonai; Hernandez-Lopez, Francisco

    2016-10-01

    We propose a two-shot fringe analysis method for Fringe Patterns (FPs) with random phase-shift and changes in illumination components. These conditions reduce the acquisition time and simplify the experimental setup. Our method builds upon a Gabor Filter (GF) bank that eliminates noise and estimates the phase from the FPs. The GF bank allows us to obtain two phase maps with a sign ambiguity between them. Due to the fact that the random sign map is common to both computed phases, we can correct the sign ambiguity. We estimate a local phase-shift from the absolute wrapped residual between the estimated phases. Next, we robustly compute the global phase-shift. In order to unwrap the phase, we propose a robust procedure that interpolates unreliable phase regions obtained after applying the GF bank. We present numerical experiments that demonstrate the performance of our method.

  4. Fringe field interference of neighbor magnets in China spallation neutron source

    NASA Astrophysics Data System (ADS)

    Li, L.; Kang, W.; Wu, X.; Deng, C. D.; Li, S.; Yang, M.; Zhou, J. X.; Liu, Y. Q.; Wu, Y. W.

    2016-12-01

    In CSNS accelerator construction, the field measurement of all RCS magnets have been finished and the magnets have been installed in the tunnel before the end of 2015. The electromagnetic quadrupoles have a large aperture and the core-to-core distance between magnets is rather short in some places. The corrector magnet or the sextupole magnet is closer to one of the quadrupole magnets which caused certain interference. The interference caused by magnetic fringe field has been appeared and it becomes a significant issue in beam dynamics for beam loss control in this high-intensity proton accelerator. We have performed 3D computing simulations to study integral field distributions between the quadrupole and the corrector magnets, and the sextupole and the other quadrupole magnets. The effect of the magnetic fringe field and the interference has been investigated with different distances of the neighbor magnets. The simulation and the field measurement results will be introduced in this paper.

  5. Three-dimensional surface inspection for semiconductor components with fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Deng, Fuqin; Ding, Yi; Peng, Kai; Xi, Jiangtao; Yin, Yongkai; Zhu, Ziqi

    2016-11-01

    With the increasing integration level of components in modern electronic devices, three-dimensional automated optical inspection has been widely used in the manufacturing process of electronic and communication industries to improve the product quality. In this paper, we develop a three-dimensional inspection and metrology system for semiconductor components with fringe projection profilometry, which is composed of industry camera, telecentric lens and projection module. This system is used to measure the height, flatness, volume, shape, coplanarity for quality checking. To detect the discontinuous parts in the internal surface of semiconductor components, we employ the fringes with multiple spatial frequencies to avoid the measurement ambiguity. The complete three-dimensional information of semiconductor component is obtained by fusing the absolute phase maps from different views. The practical inspection results show that the depth resolution of our system reaches 10 μm . This system can be further embedded for the online inspection of various electronic and communication products.

  6. Vibration analysis of a metal plate by using laser vibrometry and fringe projection

    NASA Astrophysics Data System (ADS)

    Barrientos, B.; Moreno, D.; Cywiak, M.; Pérez-López, C.; Mendoza-Santoyo, F.

    2006-02-01

    Mechanical devices are normally used under conditions of dynamic motion. Due to resonance effects, this condition produces undesired modes of vibration, which are necessary to be measured for satisfactory design. This work describes the use of laser vibrometry in conjunction with fringe projection and the proper orthogonal decomposition method to analyze the dynamical behaviour of a metal plate when subjected to external vibration. In the proposed method, point velocity measurements of the metal plate obtained by a laser vibrometer are put in phase by the use of an instantaneous out-of-plane displacement image obtained by the fringe projection technique. In this case, the plate was driven by an electromagnetic shaker which in turn was fed with a range of frequencies that covered the first 4 resonant modes.

  7. Fringe structures and tunable bandgap width of 2D boron nitride nanosheets.

    PubMed

    Feng, Peter; Sajjad, Muhammad; Li, Eric Yiming; Zhang, Hongxin; Chu, Jin; Aldalbahi, Ali; Morell, Gerardo

    2014-01-01

    We report studies of the surface fringe structures and tunable bandgap width of atomic-thin boron nitride nanosheets (BNNSs). BNNSs are synthesized by using digitally controlled pulse deposition techniques. The nanoscale morphologies of BNNSs are characterized by using scanning electron microscope (SEM), and transmission electron microscopy (TEM). In general, the BNNSs appear microscopically flat in the case of low temperature synthesis, whereas at high temperature conditions, it yields various curved structures. Experimental data reveal the evolutions of fringe structures. Functionalization of the BNNSs is completed with hydrogen plasma beam source in order to efficiently control bandgap width. The characterizations are based on Raman scattering spectroscopy, X-ray diffraction (XRD), and FTIR transmittance spectra. Red shifts of spectral lines are clearly visible after the functionalization, indicating the bandgap width of the BNNSs has been changed. However, simple treatments with hydrogen gas do not affect the bandgap width of the BNNSs.

  8. Spectral interference fringes in chirped large-mode-area fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Poozesh, Reza; Madanipour, Khosro; Vatani, Vahid

    2016-09-01

    Spectral interference fringes were experimentally observed in chirped large mode area fiber Bragg grating (CFBG) in the overlapping region of the reflected spectrum of fiber modes by a high resolution spectrometer. It was demonstrated that the interference is due to optical path difference of the reflected modes in slight chirped FBGs. By assuming chirped fiber Bragg gratings as a Fabry-Perot (FP) cavity, free spectral range (FSR) of FP was calculated 0.08 nm which is matched with measurement very well. Furthermore, the experiments show that axial tension and temperature changes of the CFBG do not have observable effects on the magnitude of FSR, however coiling of the fiber deceases spectral interference fringe amplitude without sensible effect on FSR magnitude. The results of this work can be utilized in bending sensors.

  9. Closed-form Maker fringe formulas for poled polymer thin films in multilayer structures.

    PubMed

    Park, Dong Hun; Herman, Warren N

    2012-01-02

    We report new closed-form expressions for Maker fringes of anisotropic and absorbing poled polymer thin films in multilayer structures that include back reflections of both fundamental and second-harmonic waves. The expressions, based on boundary conditions at each interface, can be applied to multilayer structures containing a buffer and a transparent conducting oxide layer, which might enhance multiple reflections of fundamental and second-harmonic waves inside a nonlinear thin film layer. This formulation facilitates Maker fringe analysis for a sample containing additional multilayer structures on either side of a poled polymer thin film. Experimental data and numerical simulations are given to indicate the importance of inclusion of such a reflective layer in analyses for reliable characterization of second-harmonic tensor elements.

  10. Inner vane fringes of barn owl feathers reconsidered: morphometric data and functional aspects.

    PubMed

    Bachmann, Thomas; Wagner, Hermann; Tropea, Cameron

    2012-07-01

    It is a challenge to understand how barn owls (Tyto alba) reduce noise during flight to be able to hunt small mammals by audition. Several specializations of the wing and the wing feathers have been implicated in noise reduction. What has been overlooked so far are the fringes at the inner vanes of remiges. We demonstrated, by using precise imaging techniques combined with morphometric measurements and air-flow studies, that these fringes merge into neighboring feather vanes by gliding into the grooves at the lower wing surface that are formed by parallel-oriented barb shafts. The connection of adjacent feathers results in a smooth lower wing surface and thus reduces sharp and noisy edges. This finding sheds new light on the mechanisms underlying noise reduction of flying owls.

  11. Carrier fringes in the two-aperture common-path interferometer.

    PubMed

    Meneses-Fabian, Cruz; Rodriguez-Zurita, Gustavo

    2011-03-01

    We present a method to introduce a linear phase into an interference pattern. This phase is introduced when a grating is placed outside of the Fourier plane of a two-aperture common-path interferometer, which is built using a 4f optical imaging system. Based on an analysis of near-field diffraction, the introduction of the carrier fringes is mathematically justified. It is important to note that no tilt between the two beams is requested to produce this effect, and it turns out to be simpler, easier, and more versatile than other existing methods. The main attributes and advantages of the setup will be discussed and illustrated in detail with experimental fringe patterns.

  12. Tailored Fringed Platforms Produced by Laser Interference for Aligned Neural Cell Growth.

    PubMed

    Peláez, Ramón J; González-Mayorga, Ankor; Gutiérrez, María C; García-Rama, Concepción; Afonso, Carmen N; Serrano, María C

    2016-02-01

    Ordering neural cells is of interest for the development of neural interfaces. The aim of this work is to demonstrate an easy-to-use, versatile, and cost/time effective laser-based approach for producing platforms that promote oriented neural growth. We use laser interferometry to generate fringed channels with topography on partially reduced graphene oxide layers as a proof-of-concept substrate. We study cell adhesion, morphology, viability, and differentiation in cultures of embryonic neural progenitor cells on platforms with a 9.4 μm period. Results evidence that fringed platforms significantly promote neurite alignment (≈50% at 6 d), while preserving viability and neural differentiation.

  13. Visual modeling of laser Doppler anemometer signals by moiré fringes.

    PubMed

    Durst, F; Stevenson, W H

    1976-01-01

    This report describes the employment of moiré patterns to model visually interference phenomena in general and laser Doppler anemometer signals in particular. The modeling includes signals created in dual beam and reference beam anemometers by both single particles and particle pairs. The considerations are extended to visual modeling of multiparticle signals and the decay of signal quality in the presence of many particles. The fringe model of the laser Doppler anemometer is also considered, and moiré patterns are employed to demonstrate the interference fringes in the crossover region of two intersecting laser beams. Gaussian beam properties are taken into account to allow the effects of improperly designed optical systems to be studied. Instructions for using computer generated transparencies to produce the different moiré patterns are provided to allow the reader to study in detail the various interference phenomena described.

  14. Phase-stepping fiber-optic projected fringe system for surface topography measurements

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R. (Inventor); Beheim, Glenn (Inventor)

    1992-01-01

    A projected fringe interferometer for measuring the topography of an object is presented. The interferometer periodically steps the phase angle between a pair of light beams emanating from a common source. The steps are pi/2 radians (90 deg) apart, and at each step a video image of the fringes is recorded and stored. Photodetectors measure either the phase and theta of the beams or 2(theta). Either of the measures can be used to control one of the light beams so that the 90 deg theta is accurately maintained. A camera, a computer, a phase controller, and a phase modulator established closed-loop control of theta. Measuring the phase map of a flat surface establishes a calibration reference.

  15. Blind phase error suppression for color-encoded digital fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Ma, S.; Zhu, R.; Quan, C.; Li, B.; Tay, C. J.; Chen, L.

    2012-04-01

    Color-encoded digital fringe projection profilometry (CDFPP) has the advantage of fast speed, non-contact and full-field testing. It is one of the most important dynamic three-dimensional (3D) profile measurement techniques. However, due to factors such as color cross-talk and gamma distortion of electro-optical devices, phase errors arise when conventional phase-shifting algorithms with fixed phase shift values are utilized to retrieve phases. In this paper, a simple and effective blind phase error suppression approach based on isotropic n-dimensional fringe pattern normalization (INFPN) and carrier squeezing interferometry (CSI) is proposed. It does not require pre-calibration for the gamma and color-coupling coefficients or the phase shift values. Simulation and experimental works show that our proposed approach is able to effectively suppress phase errors and achieve accurate measurement results in CDFPP.

  16. A New Facility for Testing Superconducting Solenoid Magnets with Large Fringe Fields at Fermilab

    SciTech Connect

    Orris, D.; Carcagno, R.; Nogiec, J.; Rabehl, R.; Sylvester, C.; Tartaglia, M.

    2013-09-01

    Testing superconducting solenoid with no iron flux return can be problematic for a magnet test facility due to the large magnetic fringe fields generated. These large external fields can interfere with the operation of equipment while precautions must be taken for personnel supporting the test. The magnetic forces between the solenoid under test and the external infrastructure must also be taken under consideration. A new test facility has been designed and built at Fermilab specifically for testing superconducting magnets with large external fringe fields. This paper discusses the test stand design, capabilities, and details of the instrumentation and controls with data from the first solenoid tested in this facility: the Muon Ionization Cooling Experiment (MICE) coupling coil.

  17. A surface profile reconstruction system using sinusoidal phase-modulating interferometry and fiber-optic fringe projection

    NASA Astrophysics Data System (ADS)

    En, Bo; Fa-jie, Duan; Chang-rong, Lv; Fan, Feng; Xiao, Fu

    2014-06-01

    A fiber-optic sinusoidal phase modulating (SPM) interferometer for surface profile reconstruction is presented. Sinusoidal phase modulation is created by modulating the drive voltage of the piezoelectric transducer. The surface profile is constructed basing on fringe projection. Fringe patterns are vulnerable to external disturbances such as temperature fluctuation and mechanical vibration, which cause phase drift and decrease measuring accuracy. We build a closed-loop feedback phase compensation system, the bias value of external disturbances superimposed on fringe patterns can be reduced to about 50 mrad, and the phase stability for interference fringes is less than 5.76 mrad. By measuring the surface profile of a paper plate for two times, the repeatability is estimated to be about 11 nm, and is equivalent to be about λ/69. For a plane with 100 × 100 points, a single measurement takes less than 140 ms, and the feasibility for real-time profile measurement with high accuracy has been verified.

  18. First 230 GHz VLBI fringes on 3C 279 using the APEX Telescope

    NASA Astrophysics Data System (ADS)

    Wagner, J.; Roy, A. L.; Krichbaum, T. P.; Alef, W.; Bansod, A.; Bertarini, A.; Güsten, R.; Graham, D.; Hodgson, J.; Märtens, R.; Menten, K.; Muders, D.; Rottmann, H.; Tuccari, G.; Weiss, A.; Wieching, G.; Wunderlich, M.; Zensus, J. A.; Araneda, J. P.; Arriagada, O.; Cantzler, M.; Duran, C.; Montenegro-Montes, F. M.; Olivares, R.; Caro, P.; Bergman, P.; Conway, J.; Haas, R.; Johansson, J.; Lindqvist, M.; Olofsson, H.; Pantaleev, M.; Buttaccio, S.; Cappallo, R.; Crew, G.; Doeleman, S.; Fish, V.; Lu, R.-S.; Ruszczyk, C.; SooHoo, J.; Titus, M.; Freund, R.; Marrone, D.; Strittmatter, P.; Ziurys, L.; Blundell, R.; Primiani, R.; Weintroub, J.; Young, K.; Bremer, M.; Sánchez, S.; Marscher, A. P.; Chilson, R.; Asada, K.; Inoue, M.

    2015-09-01

    Aims: We report about a 230 GHz very long baseline interferometry (VLBI) fringe finder observation of blazar 3C 279 with the APEX telescope in Chile, the phased submillimeter array (SMA), and the SMT of the Arizona Radio Observatory (ARO). Methods: We installed VLBI equipment and measured the APEX station position to 1 cm accuracy (1σ). We then observed 3C 279 on 2012 May 7 in a 5 h 230 GHz VLBI track with baseline lengths of 2800 Mλ to 7200 Mλ and a finest fringe spacing of 28.6 μas. Results: Fringes were detected on all baselines with signal-to-noise ratios of 12 to 55 in 420 s. The correlated flux density on the longest baseline was ~0.3 Jy beam-1, out of a total flux density of 19.8 Jy. Visibility data suggest an emission region ≲ 38 μas in size, and at least two components, possibly polarized. We find a lower limit of the brightness temperature of the inner jet region of about 1010 K. Lastly, we find an upper limit of 20% on the linear polarization fraction at a fringe spacing of ~ 38 μas. Conclusions: With APEX the angular resolution of 230 GHz VLBI improves to 28.6 μas. This allows one to resolve the last-photon ring around the Galactic Center black hole event horizon, expected to be 40 μas in diameter, and probe radio jet launching at unprecedented resolution, down to a few gravitational radii in galaxies like M 87. To probe the structure in the inner parsecs of 3C 279 in detail, follow-up observations with APEX and five other mm-VLBI stations have been conducted (March 2013) and are being analyzed.

  19. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

    NASA Astrophysics Data System (ADS)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H.

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp = 200…600 μm, porosity ε = 0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol) = 0 after t = 6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  20. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

    PubMed

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  1. High-resolution liquid-crystal phase grating formed by fringing fields from interdigitated electrodes.

    PubMed

    Lindquist, R G; Kulick, J H; Nordin, G P; Jarem, J M; Kowel, S T; Friends, M; Leslie, T M

    1994-05-01

    We report the formation of thin anisotropic phase gratings in a nematic liquid-crystalline film by use of lateral (fringing) electric fields induced by transparent interdigitated electrodes. These gratings yield high diffraction efficiency (>30%) with a strong dependence on the readout beam incidence angle. In addition, the formation of a defect wall is observed that has a significant effect on the diffraction properties of the phase grating.

  2. Fast in-situ tool inspection based on inverse fringe projection and compact sensor heads

    NASA Astrophysics Data System (ADS)

    Matthias, Steffen; Kästner, Markus; Reithmeier, Eduard

    2016-11-01

    Inspection of machine elements is an important task in production processes in order to ensure the quality of produced parts and to gather feedback for the continuous improvement process. A new measuring system is presented, which is capable of performing the inspection of critical tool geometries, such as gearing elements, inside the forming machine. To meet the constraints on sensor head size and inspection time imposed by the limited space inside the machine and the cycle time of the process, the measuring device employs a combination of endoscopy techniques with the fringe projection principle. Compact gradient index lenses enable a compact design of the sensor head, which is connected to a CMOS camera and a flexible micro-mirror based projector via flexible fiber bundles. Using common fringe projection patterns, the system achieves measuring times of less than five seconds. To further reduce the time required for inspection, the generation of inverse fringe projection patterns has been implemented for the system. Inverse fringe projection speeds up the inspection process by employing object-adapted patterns, which enable the detection of geometry deviations in a single image. Two different approaches to generate object adapted patterns are presented. The first approach uses a reference measurement of a manufactured tool master to generate the inverse pattern. The second approach is based on a virtual master geometry in the form of a CAD file and a ray-tracing model of the measuring system. Virtual modeling of the measuring device and inspection setup allows for geometric tolerancing for free-form surfaces by the tool designer in the CAD-file. A new approach is presented, which uses virtual tolerance specifications and additional simulation steps to enable fast checking of metric tolerances. Following the description of the pattern generation process, the image processing steps required for inspection are demonstrated on captures of gearing geometries.

  3. The classification of LANDSAT data for the Orlando, Florida, urban fringe area

    NASA Technical Reports Server (NTRS)

    Walthall, C. L.; Knapp, E. M.

    1978-01-01

    Procedures used to map residential land cover on the Orlando, Florida, Urban fringe zone are detailed. The NASA Bureau of the Census Applications Systems Verification and Transfer project and the test site are described as well as the LANDSAT data used as the land cover information sources. Both single-date LANDSAT data processing and multitemporal principal components LANDSAT data processing are described. A summary of significant findings is included.

  4. Representation of image distortion by Moiré fringes at phase singularity state.

    PubMed

    Samavati, Katayoon; Taghi Tavassoly, M; Ghomi, Hamid

    2017-01-10

    When a grating is imaged by an optical imaging system, due to the aberrations of the system, the parameters of the image grating suffer minute gradual changes across the image. Superimposing an ideal grating image over the real grating image at the phase singularity state of the two gratings leads to phase contours, special Moiré fringes, which directly represent the distortions over the image. In this report, after a brief review of the required theoretical bases, we show when the parameters of a grating change linearly the corresponding Moiré fringes at the singularity state are represented by quadratic functions, and for nonlinear changes higher order functions are involved. Thus, by imposing desired changes on the parameters of a grating one can produce Moiré fringes satisfying functions of required orders. In the experimental part of the report we apply the technique to evaluate the image distortions imposed by a conventional camera and cameras installed in a mobile and in a tablet.

  5. A SEARCH FOR SEPARATED FRINGE PACKET BINARIES USING THE CHARA ARRAY

    SciTech Connect

    Raghavan, Deepak; McAlister, Harold A.; Farrington, Chris D.; Ten Brummelaar, Theo A.; Sturmann, Laszlo; Sturmann, Judit; Turner, Nils H.; Ridgway, Stephen T.

    2012-01-20

    We present the results of a comprehensive search for new companions to nearby solar-type stars using the separated fringe packet (SFP) technique at the Center for High Angular Resolution Astronomy (CHARA) Array. Our search included 636 observations of 186 stars, searching for companions with separations of approximately 8-80 mas and moderate brightness ratios ({Delta}K {approx}< 1.5). This survey was undertaken to support a comprehensive assessment of companions to solar-type stars within 25 pc. We detected separated fringe companions to two stars (HD 3196 and 79096) and found faint companion signatures to two more stars (HD 98231 and 137763). All of these companions are previously known by spectroscopic methods, and three of them have speckle interferometric observations as well. The faint companion seen to HD 98231 represents the first visual detection of this spectroscopic companion. Our null detection for new companions implies that the presumed gap between spectroscopic and visual techniques has largely been filled for nearby solar-type stars, thanks to systematic radial-velocity observations over multiple decades and a thorough coverage using visual techniques, especially speckle interferometric observations. We also generate simulated fringe packets to derive detection limits for SFP binaries using the CHARA Array.

  6. Theoretical study of the properties of X-ray diffraction moiré fringes. I.

    PubMed

    Yoshimura, Jun-ichi

    2015-07-01

    A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997). Acta Cryst. A53, 810-812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect of Pendellösung intensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general.

  7. Optimal multi-photon phase sensing with a single interference fringe

    PubMed Central

    Xiang, G. Y.; Hofmann, H. F.; Pryde, G. J.

    2013-01-01

    Quantum entanglement can help to increase the precision of optical phase measurements beyond the shot noise limit (SNL) to the ultimate Heisenberg limit. However, the N-photon parity measurements required to achieve this optimal sensitivity are extremely difficult to realize with current photon detection technologies, requiring high-fidelity resolution of N + 1 different photon distributions between the output ports. Recent experimental demonstrations of precision beyond the SNL have therefore used only one or two photon-number detection patterns instead of parity measurements. Here we investigate the achievable phase sensitivity of the simple and efficient single interference fringe detection technique. We show that the maximally-entangled “NOON” state does not achieve optimal phase sensitivity when N > 4, rather, we show that the Holland-Burnett state is optimal. We experimentally demonstrate this enhanced sensitivity using a single photon-counted fringe of the six-photon Holland-Burnett state. Specifically, our single-fringe six-photon measurement achieves a phase variance three times below the SNL. PMID:24067490

  8. Noise Removal in Interferometric Fringe Patterns: Application to Quantitative Stress Determination Using Speckle Interferometry

    NASA Astrophysics Data System (ADS)

    Diallo, M.; Rumzan, I.; Schmitt, D. R.

    2001-12-01

    Dual beam " Electronic speckle Interferometry" (EPSI) is used to record stress-relief displacements induced by the drilling of blind holes into prestressed materials. Interpretation of the resulting interferograms in term of stress magnitude can be achieved by iterative least squares minimization approach that uses the positions of fringes minima and maxima. An automated picking of these extrema can often be difficult because of superimposed noise that degrade the data quality. To improve the accuracy subsequent fringe positions picking, we apply a nonlinear image filtering technique based on inhomogeneous diffusion to remove the noise and smooth the extrema. In this technique, the image is represented as a surface in three-space and the inhomogeneous diffusion is based on analogy to the heat diffusion with the particularity that the conduction coefficient, taken as the inverse of the surface gradient is spatially variant. The rate of the surface diffusion is only dependent on the average value of the normal curvature in any two orthogonal directions and not on its magnitude thus allowing preservation of image structure. The noise removal process is achieved through averaging of its divergent direction. This averaging preserves "clean" image structures as their direction is nondivergent. Application of this technique on both synthetic and experimental data provided satisfactory results. Although our application focuses on the determination of mechanical parameters, the method could be directly applied to assist the interpretation of SAR interferometric fringe patterns or in reducing the noise in otherwise coherent seismic images. >http://www-geo.phys.ualberta.ca/ ~irumzan

  9. Patch-wise denoising of phase fringe patterns based on matrix enhancement

    NASA Astrophysics Data System (ADS)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2016-12-01

    We propose a new approach for the denoising of a phase fringe pattern recorded in an optical interferometric setup. The phase fringe pattern which is generally corrupted by high amount of speckle noise is first converted into an exponential phase field. This phase field is divided into a number of overlapping patches. Owing to the small size of each patch, the presence of a simple structure of the interference phase is assumed in it. Accordingly, the singular value decomposition (SVD) of the patch allows us to separate the signal and noise components effectively. The patch is reconstructed only with the signal component. In order to further improve the robustness of the proposed method, an enhanced data matrix is generated using the patch and the SVD of this enhanced matrix is computed. The matrix enhancement results in an increased dimension of the noise subspace which thus accommodates more amount of noise component. Reassignment of the filtered pixels of the preceding patch in the current patch improves the noise filtering accuracy. The fringe denoising capability in function of the noise level and the patch size is studied. Simulation and experimental results are provided to demonstrate the practical applicability of the proposed method.

  10. A phase retrieval algorithm based on color-frequency encoding for fringe reflection technique

    NASA Astrophysics Data System (ADS)

    Ma, Suodong; Li, Bo

    2016-09-01

    Free-form optics have a wide range of applications since they can simplify the structure of an optical system, meanwhile significantly improving the system performance. Compared to optics with traditional profiles, optical testing for freeform surface is more difficult. Although a laser interferometer can reach the surface measurement precision in nanometer scale, it has problems of a limited measurement range, a complex system configuration and relatively high requirements of working conditions. Fringe reflection technique (FRT) is gradually becoming a powerful tool for free-form surface testing owing to its advantages of simple system structure, high measurement accuracy, large dynamic range, etc. However, multiple groups of fringe images are required to display in two orthogonal directions respectively during the FRT measurement to obtain the corresponding surface gradient information. It hinders the fast detection of free-form surface to a certain extent. In order to overcome the above shortcoming, a phase retrieval algorithm based on color-frequency encoding for FRT is proposed in this paper, which can achieve the absolute phase meanwhile reducing the required number of fringe images for measurement. Experimental results demonstrate the effectiveness of the proposed method.

  11. Dispersal of forest insects

    NASA Technical Reports Server (NTRS)

    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.

  12. Visualizing Dispersion Interactions

    ERIC Educational Resources Information Center

    Gottschalk, Elinor; Venkataraman, Bhawani

    2014-01-01

    An animation and accompanying activity has been developed to help students visualize how dispersion interactions arise. The animation uses the gecko's ability to walk on vertical surfaces to illustrate how dispersion interactions play a role in macroscale outcomes. Assessment of student learning reveals that students were able to develop…

  13. Dispersion strengthened copper

    DOEpatents

    Sheinberg, H.; Meek, T.T.; Blake, R.D.

    1990-01-09

    A composition of matter is described which is comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide. A method for making this composition of matter is also described. This invention relates to the art of powder metallurgy and, more particularly, it relates to dispersion strengthened metals.

  14. Seed dispersal in fens

    USGS Publications Warehouse

    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.

  15. Spores Disperse, Too!

    ERIC Educational Resources Information Center

    Schumann, Donna N.

    1981-01-01

    Suggests the use of spores and spore-producing structures to show adaptations facilitating spore dispersal and dispersal to favorable environments. Describes several activities using horsetails, ferns, and mosses. Lists five safety factors related to use of mold spores in the classroom. (DS)

  16. Improved 3D displacement measurements method and calibration of a combined fringe projection and 2D-DIC system

    NASA Astrophysics Data System (ADS)

    Siegmann, Philip; Felipe-Sese, Luis; Diaz-Garrido, Francisco

    2017-01-01

    An improved measurement method and an automatic calibration procedure are proposed for a combined 2D Digital Image Correlation and Fringe Projection system that allows measuring in- and out-of-plane displacement maps with only one image at each deformation stage of a specimen. The proposed method increases the accuracy and range of the out-of-plane displacements by taking into account the divergences of both the projected fringes (uncollimated) and the camera (with non-zero FOV). The calibration is performed automatically by acquiring a sequence of images of a reference plane by displacing perpendicular to it the camera and fringe projector with a motorized translation stage. The acquired images are then used to obtain a fringe function for each pixel and the necessary parameters required for the correction of the in-plane displacements. Furthermore, a closed form expression is obtained that relates the out-of-plane displacements with the shifted phase at each pixel for a given experimental set-up. This expression is in good agreement with the fringe function obtained by fitting a simple 2nd order polynomial to the experimental obtained calibration data. Finally, the polynomial approach is proposed as a fringe function because it avoids the errors in the determination of the required parameters of the theoretical expression as well as some small misalignment or aberration effects.

  17. 3D phase-shifting fringe projection system on the basis of a tailored free-form mirror.

    PubMed

    Zwick, Susanne; Heist, Stefan; Steinkopf, Ralf; Huber, Sandra; Krause, Sylvio; Bräuer-Burchardt, Christian; Kühmstedt, Peter; Notni, Gunther

    2013-05-10

    Phase-shifting fringe projection is an effective method to perform 3D shape measurements. Conventionally, fringe projection systems utilize a digital projector that images fringes into the measurement plane. The performance of such systems is limited to the visible spectral range, as most projectors experience technical limitations in UV or IR spectral ranges. However, for certain applications these spectral ranges are of special interest. We present a wideband fringe projector that has been developed on the basis of a picture generating beamshaping mirror. This mirror generates a sinusoidal fringe pattern in the measurement plane without any additional optical elements. Phase shifting is realized without any mechanical movement by a multichip LED. As the system is based on a single mirror, it is wavelength-independent in a wide spectral range and therefore applicable in UV and IR spectral ranges. We present the design and a realized setup of this fringe projection system and the characterization of the generated intensity distribution. Experimental results of 3D shape measurements are presented.

  18. Rates of Gravel Dispersion

    NASA Astrophysics Data System (ADS)

    Haschenburger, J. K.

    2010-12-01

    Sediment transfers in gravel-bed rivers involve the three-dimensional dispersion of mixed size sediment. From a kinematics standpoint, few studies are available to inform on the streamwise and vertical rates of sediment dispersion in natural channels. This research uses a gravel tracing program to quantify dispersion rates over 19 flood seasons. Empirical observations come from Carnation Creek, a small gravel-bed river with large woody debris located on the west coast of Vancouver Island, Canada. Frequent floods and the relatively limited armor layer facilitate streambed activity and relatively high bedload transport rates, typically under partial sediment transport conditions. Over 2500 magnetically tagged stones, ranging in size from 16 to 180 mm, were deployed on the bed surface between 1989 and 1992 in four generations. To quantify gravel dispersion over distances up to 2.6 km, observations are taken from 11 recoveries. Over 280 floods capable of moving bedload occurred during this period, with five exceeding the estimated bankfull discharge. Streamwise dispersion is quantified by virtual velocity, while dispersion into the streambed is quantified by a vertical burial rate. The temporal trend in streamwise dispersion rates is described by a power function. Initial virtual velocities decline rapidly from around 1.4 m/hr to approach an asymptote value of about 0.2 m/hr. The rapid change corresponds to a significant increase in the proportion of buried tracers due to vertical mixing. Initial burial rates reflect the magnitude of the first flood after tracer deployment and range from 0.07 to 0.46 cm/hr depending on tracer generation. Burial rates converge to about 0.06 cm/hr after the fourth flood season and then gradually decline to about 0.01 cm/hr. Thus, the rate of streamwise dispersion exceeds that of vertical dispersion by three orders of magnitude when the movement of sediment routinely activated by floods is considered.

  19. Chirped laser dispersion spectroscopy using a directly modulated quantum cascade laser

    SciTech Connect

    Hangauer, Andreas Nikodem, Michal; Wysocki, Gerard; Spinner, Georg

    2013-11-04

    Chirped laser dispersion spectroscopy (CLaDS) utilizing direct modulation of a quantum cascade laser (QCL) is presented. By controlling the laser bias nearly single- and dual-sideband CLaDS operation can be realized in an extremely simplified optical setup with no external optical modulators. Capability of direct single-sideband modulation is a unique feature of QCLs that exhibit a low linewidth enhancement factor. The developed analytical model shows excellent agreement with the experimental, directly modulated CLaDS spectra. This method overcomes major technical limitations of mid-infrared CLaDS systems by allowing significantly higher modulation frequencies and eliminating optical fringes introduced by external modulators.

  20. Surface profile measurement using spatially dispersed short coherence interferometry

    NASA Astrophysics Data System (ADS)

    Hassan, Mothana A.; Martin, Haydn; Jiang, Xiangqian

    2014-04-01

    Improved online techniques for surface profile measurement can be beneficial in high/ultra-precision manufacturing, in terms of enabling manufacture and reducing costs. This paper introduces a spatially dispersed short-coherence interferometer sourced by a super luminescent diode. This technique uses a broadband light source, which is spatially dispersed across a surface using a reflective grating and a scan lens. In this way, the phase data pertaining to surface at height is spectrally encoded. The light reflected from the surface is interfered with a reference beam in a Michelson interferometer, after which the resulting fringes are interrogated by a spectrometer. Phase shifting interferometry is used to extract the spectrally encoded phase information by analysing four captured frames using a Carré algorithm procedure; in this way, surface height can be determined across a profile on a sample. The short coherent light utilized in this interferometric technique means it has the potential for an application as a remote probe through an optical fibre link. This paper describes the concept of a spatially dispersed short coherence interferometer and provides some of the initial experimental results.

  1. 6-station, 5-baseline fringe tracking with the new classic data acquisition system at the Navy Precision Optical Interferometer

    NASA Astrophysics Data System (ADS)

    Landavazo, M. I.; Jorgensen, A. M.; Sun, B.; Newman, K.; Mozurkewich, David; van Belle, G. T.; Hutter, Donald J.; Schmitt, H. R.; Armstrong, J. T.; Baines, E. K.; Restaino, S. R.

    2014-07-01

    The Navy Precision Optical Interferometer (NPOI) has a station layout which makes it uniquely suited for imaging. Stellar surface imaging requires a variety of baseline lengths and in particular long baselines with resolution much smaller than the diameter of the target star. Because the fringe signal-to-noise ratio (SNR) is generally low on such long baselines, fringe-tracking cannot be carried out on those baselines directly. Instead, baseline bootstrapping must be employed in which the long baseline is composed of a number of connected shorter baselines. When fringes are tracked on all the shorter baselines fringes are also present on the long baseline. For compact sources, such as stellar disks, the shorter baselines generally have higher SNR and making them short enough that the source is unresolved by them is ideal. Thus, the resolution, or number of pixels across a stellar disk, is roughly equal to the ratio of the length of the long baseline to the length of the short baselines. The more bootstrapped baselines, the better the images produced. If there is also a wide wavelength coverage, wavelength bootstrapping can also be used under some circumstances to increase the resolution further. The NPOI is unique in that it allows 6-station, 5-baseline bootstrapping, the most of any currently operating interferometer. Furthermore, the NPOI Classic beam combiner has wavelength coverage from 450 nm to 850 nm. However, until now, this capability has not been fully exploited. The stellar surface imaging project which was recently funded by the National Science Foundation is exploiting this capability. The New Classic data acquisition system, reported separately, is the hardware which delivers the data to the fringe-tracking algorithm. In this paper we report on the development of the fringe-tracking capability with the New Classic data acquisition system. We discuss the design of the fringe tracking algorithm and present performance results from simulations and on sky

  2. Dispersion strengthened copper

    DOEpatents

    Sheinberg, Haskell; Meek, Thomas T.; Blake, Rodger D.

    1990-01-01

    A composition of matter comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide, and a method for making this composition of matter.

  3. Dispersion strengthened copper

    DOEpatents

    Sheinberg, Haskell; Meek, Thomas T.; Blake, Rodger D.

    1989-01-01

    A composition of matter comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide, and a method for making this composition of matter.

  4. Nanocrystal dispersed amorphous alloys

    NASA Technical Reports Server (NTRS)

    Perepezko, John H. (Inventor); Allen, Donald R. (Inventor); Foley, James C. (Inventor)

    2001-01-01

    Compositions and methods for obtaining nanocrystal dispersed amorphous alloys are described. A composition includes an amorphous matrix forming element (e.g., Al or Fe); at least one transition metal element; and at least one crystallizing agent that is insoluble in the resulting amorphous matrix. During devitrification, the crystallizing agent causes the formation of a high density nanocrystal dispersion. The compositions and methods provide advantages in that materials with superior properties are provided.

  5. A Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing the Functions of Tidal Fringe Wetlands Along the Mississippi and Alabama Gulf Coast

    DTIC Science & Technology

    2007-04-01

    Hydrogeomorphic Approach vernal pools, prairie potholes in North and South Dakota, playa lakes in the high plains of Texas, kettles in New England...through evapotranspiration, intermittent or perennial outlets, or recharge to groundwater. Prairie potholes, playa lakes , vernal pools, and cypress domes...alterniflora salt marshes are a common example of tidal fringe wetlands. Lacustrine Fringe Lacustrine fringe wetlands are adjacent to lakes where

  6. Fickian dispersion is anomalous

    DOE PAGES

    Cushman, John H.; O’Malley, Dan

    2015-06-22

    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 wemore » 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. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.« less

  7. Fickian dispersion is anomalous

    SciTech Connect

    Cushman, John H.; O’Malley, Dan

    2015-06-22

    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. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.

  8. Fickian dispersion is anomalous

    NASA Astrophysics Data System (ADS)

    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.

  9. Endoscopic fringe projection for in-situ inspection of a sheet-bulk metal forming process

    NASA Astrophysics Data System (ADS)

    Matthias, Steffen; Kästner, Markus; Reithmeier, Eduard

    2015-05-01

    Sheet-bulk metal forming is a new production process capable of performing deep-drawing and massive forming steps in a single operation. However, due to the high forming forces of the forming process, continuous process control is required in order to detect wear on the forming tool before production quality is impacted. To be able to measure the geometry of the forming tool in the limited space of forming presses, a new inspection system is being developed within the SFB/TR 73 collaborative research center. In addition to the limited space, the process restricts the amount of time available for inspection. Existing areal optical measurement systems suffer from shadowing when measuring the tool's inner elements, as they cannot be placed in the limited space next to the tool, while tactile measurement systems cannot meet the time restrictions for measuring the areal geometries. The new inspection system uses the fringe projection optical measurement principle to capture areal geometry data from relevant parts of the forming tool in short time. Highresolution image fibers are used to connect the system's compact sensor head to a base unit containing both camera and projector of the fringe projection system, which can be positioned outside of the moving parts of the press. To enable short measurement times, a high intensity laser source is used in the projector in combination with a digital micro-mirror device. Gradient index lenses are featured in the sensor head to allow for a very compact design that can be used in the narrow space above the forming tool inside the press. The sensor head is attached to an extended arm, which also guides the image fibers to the base unit. A rotation stage offers the possibility to capture measurements of different functional elements on the circular forming tool by changing the orientation of the sensor head next to the forming tool. During operation of the press, the arm can be travelled out of the moving parts of the forming press

  10. Population redistribution within the rural-urban fringe: a typology of small towns and rural municipalities in the state of New Jersey.

    PubMed

    Airola, T M; Parker, R A

    1983-11-01

    Population redistribution within the rural-urban fringe of the United States is examined using the state of New Jersey over the period 1970-1980 as an example. "This article provides additional evidence for the redistribution of population to the rural-urban fringe and identifies those types of municipalities that experienced the greatest growth during the 1970s. Furthermore, it finds that the factors that account for population growth at the rural-urban fringe are not only those associated with suburbanization, but also those associated with nonmetropolitan growth. It also demonstrates that population growth at the rural-urban fringe varies not only by municipal type but also by race."

  11. Dynamic recalibration of scalable fringe-projection systems for large-scale object metrology.

    PubMed

    Hovorov, Viktor; Lalor, Michael; Burton, David; Lilley, Francis

    2010-03-10

    Three-dimensional (3D) surface shape measurement is a vital component in many industrial processes. The subject has developed significantly over recent years and a number of mainly noncontact techniques now exist for surface measurement, exhibiting varying levels of maturity. Within the larger group of 3D measurement techniques, one of the most promising approaches is provided by those methods that are based upon fringe analysis. Current techniques mainly focus on the measurement of small and medium-scale objects, while work on the measurement of larger objects is not so well developed. One potential solution for the measurement of large objects that has been proposed by various researchers is the concept of performing multipanel measurement and the system proposed here uses this basic approach, but in a flexible form of a single moveable sensor head that would be cost effective for measuring very large objects. Most practical surface measurement techniques require the inclusion of a calibration stage to ensure accurate measurements. In the case of fringe analysis techniques, phase-to-height calibration is required, which includes the use of phase-to-height models. Most existing models (both analytical and empirical) are intended to be used in a static measurement mode, which means that, typically, a single calibration is performed prior to multiple measurements being made using an unvarying system geometry. However, multipanel measurement strategies do not necessarily keep the measurement system geometry constant and thus require dynamic recalibration. To solve the problem of dynamic recalibration, we propose a class of models called hybrid models. These hybrid models inherit the basic form of analytical models, but their coefficients are obtained in an empirical manner. The paper also discusses issues associated with all phase-to-height models used in fringe analysis that have a quotient form, identifying points of uncertainty and regions of distortion as issues

  12. Dynamic recalibration of scalable fringe-projection systems for large-scale object metrology

    SciTech Connect

    Hovorov, Viktor; Lalor, Michael; Burton, David; Lilley, Francis

    2010-03-10

    Three-dimensional (3D) surface shape measurement is a vital component in many industrial processes. The subject has developed significantly over recent years and a number of mainly noncontact techniques now exist for surface measurement, exhibiting varying levels of maturity. Within the larger group of 3D measurement techniques, one of the most promising approaches is provided by those methods that are based upon fringe analysis. Current techniques mainly focus on the measurement of small and medium-scale objects, while work on the measurement of larger objects is not so well developed. One potential solution for the measurement of large objects that has been proposed by various researchers is the concept of performing multipanel measurement and the system proposed here uses this basic approach, but in a flexible form of a single moveable sensor head that would be cost effective for measuring very large objects. Most practical surface measurement techniques require the inclusion of a calibration stage to ensure accurate measurements. In the case of fringe analysis techniques, phase-to-height calibration is required, which includes the use of phase-to-height models. Most existing models (both analytical and empirical) are intended to be used in a static measurement mode, which means that, typically, a single calibration is performed prior to multiple measurements being made using an unvarying system geometry. However, multipanel measurement strategies do not necessarily keep the measurement system geometry constant and thus require dynamic recalibration. To solve the problem of dynamic recalibration, we propose a class of models called hybrid models. These hybrid models inherit the basic form of analytical models, but their coefficients are obtained in an empirical manner. The paper also discusses issues associated with all phase-to-height models used in fringe analysis that have a quotient form, identifying points of uncertainty and regions of distortion as issues

  13. A general theory of interference fringes in x-ray phase grating imaging

    SciTech Connect

    Yan, Aimin; Wu, Xizeng E-mail: liu@ou.edu; Liu, Hong E-mail: liu@ou.edu

    2015-06-15

    Purpose: The authors note that the concept of the Talbot self-image distance in x-ray phase grating interferometry is indeed not well defined for polychromatic x-rays, because both the grating phase shift and the fractional Talbot distances are all x-ray wavelength-dependent. For x-ray interferometry optimization, there is a need for a quantitative theory that is able to predict if a good intensity modulation is attainable at a given grating-to-detector distance. In this work, the authors set out to meet this need. Methods: In order to apply Fourier analysis directly to the intensity fringe patterns of two-dimensional and one-dimensional phase grating interferometers, the authors start their derivation from a general phase space theory of x-ray phase-contrast imaging. Unlike previous Fourier analyses, the authors evolved the Wigner distribution to obtain closed-form expressions of the Fourier coefficients of the intensity fringes for any grating-to-detector distance, even if it is not a fractional Talbot distance. Results: The developed theory determines the visibility of any diffraction order as a function of the grating-to-detector distance, the phase shift of the grating, and the x-ray spectrum. The authors demonstrate that the visibilities of diffraction orders can serve as the indicators of the underlying interference intensity modulation. Applying the theory to the conventional and inverse geometry configurations of single-grating interferometers, the authors demonstrated that the proposed theory provides a quantitative tool for the grating interferometer optimization with or without the Talbot-distance constraints. Conclusions: In this work, the authors developed a novel theory of the interference intensity fringes in phase grating x-ray interferometry. This theory provides a quantitative tool in design optimization of phase grating x-ray interferometers.

  14. The effects of the solar radiation pressure on the F-ring particles

    NASA Astrophysics Data System (ADS)

    Sfair, R.; Giuliatti Winter, S.

    The Saturn s F-ring is a narrow ring orbiting outside the main ring system of Saturn It is located between two close satellites Prometheus the interior one and Pandora The gravitational interactions between the ring particles and the satellites can be responsible for several structures found in this ring Showalter et al 1992 showed that the F-ring material could be divided into two regions a core composed by centimeter or large particles and a dust envelope composed by mu m particles Recent observations by Cassini instruments brought more complications to this region with the discovery of two new faint rings between the A ring and Prometheus one of these rings has the satellite Atlas embedded on it These new rings are tenuous like the dust envelope which surround the F-ring and the solar radiation force can play a significant role in this dynamical environment In this work we analysed the effects due to the solar radiation forces on the particles of the F ring and the two new discovered rings In this analysis we also included the perturbation of the satellite Prometheus on the F ring particles and the satellite Atlas on the new rings particles We have numerically simulated particles with size ranging from 1-500 mu m in radius The density of these particles was assumed to be 1g cm 3 Our results show that a sample of scattered F ring particles can be trapped due to Prometheus effects However the particles from the new discovered rings have a short lifetime due to the solar radiation pressure Only those particles coorbital to Atlas

  15. A 3D Optical Surface Profilometer Using a Dual-Frequency Liquid Crystal-Based Dynamic Fringe Pattern Generator

    PubMed Central

    Joo, Kyung-Il; Kim, Mugeon; Park, Min-Kyu; Park, Heewon; Kim, Byeonggon; Hahn, JoonKu; Kim, Hak-Rin

    2016-01-01

    We propose a liquid crystal (LC)-based 3D optical surface profilometer that can utilize multiple fringe patterns to extract an enhanced 3D surface depth profile. To avoid the optical phase ambiguity and enhance the 3D depth extraction, 16 interference patterns were generated by the LC-based dynamic fringe pattern generator (DFPG) using four-step phase shifting and four-step spatial frequency varying schemes. The DFPG had one common slit with an electrically controllable birefringence (ECB) LC mode and four switching slits with a twisted nematic LC mode. The spatial frequency of the projected fringe pattern could be controlled by selecting one of the switching slits. In addition, moving fringe patterns were obtainable by applying voltages to the ECB LC layer, which varied the phase difference between the common and the selected switching slits. Notably, the DFPG switching time required to project 16 fringe patterns was minimized by utilizing the dual-frequency modulation of the driving waveform to switch the LC layers. We calculated the phase modulation of the DFPG and reconstructed the depth profile of 3D objects using a discrete Fourier transform method and geometric optical parameters. PMID:27801812

  16. Detection and evaluation of droplet and bubble fringe patterns in images of planar interferometric measurement techniques using the wavelet transform

    NASA Astrophysics Data System (ADS)

    Hardalupas, Y.; Taylor, A. M. K. P.; Zarogoulidis, K.

    2014-08-01

    The acquired images of interferometric particle sizing techniques are characterized by intense fringe pattern overlapping in dense droplet and bubble areas, which hinders the image processing process and subsequent information extraction. Methods employed, such as thresholding and the Hough transform and template cross-correlation, exhibit weaknesses when processing such dense areas of interest. We investigate the viability of applying the wavelet transform (WT) for the detection of the fringe pattern centers and the evaluation of the particle size. We present the basics of the WT using the Mexican hat, which exhibits excellent localization properties and present two different alternatives routes in detecting the fringe patterns in the compressed and uncompressed fringe pattern cases. We found that in comparison to the most reported methods for image evaluation, such as intensity thresholding and plain cross-correlation, the WT is a very efficient tool for detecting the patterns, even in images with high-number fringe pattern areas. The usage of the WT for the sizing of the imaged droplets and bubbles is also examined, in comparison to the Fast Fourier Transform (FFT).

  17. Effect of fringe-artifact correction on sub-tomogram averaging from Zernike phase-plate cryo-TEM

    PubMed Central

    Kishchenko, Gregory P.; Danev, Radostin; Fisher, Rebecca; He, Jie; Hsieh, Chyongere; Marko, Michael; Sui, Haixin

    2015-01-01

    Zernike phase-plate (ZPP) imaging greatly increases contrast in cryo-electron microscopy, however fringe artifacts appear in the images. A computational de-fringing method has been proposed, but it has not been widely employed, perhaps because the importance of de-fringing has not been clearly demonstrated. For testing purposes, we employed Zernike phase-plate imaging in a cryo-electron tomographic study of radial-spoke complexes attached to microtubule doublets. We found that the contrast enhancement by ZPP imaging made nonlinear denoising insensitive to the filtering parameters, such that simple low-frequency band-pass filtering made the same improvement in map quality. We employed sub-tomogram averaging, which compensates for the effect of the “missing wedge” and considerably improves map quality. We found that fringes (caused by the abrupt cut-on of the central hole in the phase plate) can lead to incorrect representation of a structure that is well-known from the literature. The expected structure was restored by amplitude scaling, as proposed in the literature. Our results show that de-fringing is an important part of image-processing for cryo-electron tomography of macromolecular complexes with ZPP imaging. PMID:26210582

  18. Effect of fringe-artifact correction on sub-tomogram averaging from Zernike phase-plate cryo-TEM.

    PubMed

    Kishchenko, Gregory P; Danev, Radostin; Fisher, Rebecca; He, Jie; Hsieh, Chyongere; Marko, Michael; Sui, Haixin

    2015-09-01

    Zernike phase-plate (ZPP) imaging greatly increases contrast in cryo-electron microscopy, however fringe artifacts appear in the images. A computational de-fringing method has been proposed, but it has not been widely employed, perhaps because the importance of de-fringing has not been clearly demonstrated. For testing purposes, we employed Zernike phase-plate imaging in a cryo-electron tomographic study of radial-spoke complexes attached to microtubule doublets. We found that the contrast enhancement by ZPP imaging made nonlinear denoising insensitive to the filtering parameters, such that simple low-frequency band-pass filtering made the same improvement in map quality. We employed sub-tomogram averaging, which compensates for the effect of the "missing wedge" and considerably improves map quality. We found that fringes (caused by the abrupt cut-on of the central hole in the phase plate) can lead to incorrect representation of a structure that is well-known from the literature. The expected structure was restored by amplitude scaling, as proposed in the literature. Our results show that de-fringing is an important part of image-processing for cryo-electron tomography of macromolecular complexes with ZPP imaging.

  19. Polynomial fitting model for phase reconstruction: interferograms with high fringe density

    NASA Astrophysics Data System (ADS)

    Téllez-Quiñones, Alejandro; Malacara-Doblado, Daniel; García-Márquez, Jorge

    2012-09-01

    A data fitting model is proposed to estimate phases from its cosine and sine. The a priori assumption is that the phases to be reconstructed should be expressed by polynomials. The cosine and sine of the phases are obtained from interferograms with high fringe density by generalized phase-shifting techniques The proposed method is employed for phase reconstrution by line integration of the phase gradient or any other phase-unwrapping technique and the fit is achieved by a least-squares minimization.

  20. A new optical wavelength ratio measurement apparatus: The fringe counting sigmameter

    SciTech Connect

    Juncar, P.; Elandaloussi, H.; Himbert, M.

    1994-12-31

    A new compact and achromatic Michelson-type interferometer with a variable path difference is presented. This {open_quotes}fringe-counting sigmameter{close_quotes} allows to measure optical wavelength ratios between two radiations emitted by stabilized lasers. Maintained in vacuum, this apparatus can determine wavelength/frequency laser radiation from 0,36 {mu}m to 1,5 {mu}m with a relative accuracy of 5.10{sup -9}, with the use of a reference stabilized He-Ne laser.

  1. Oil on the Water Characterization with Coherent Fringe Projection and Digital Holographic In-line Interferometry

    DTIC Science & Technology

    2013-01-01

    pu) zero indexes means, that possible constant phase shift may be introduced during reflection from the surface. From Eq.(3) it can be seen that...plot (m= M=0.5, P= 0.3369 cm, L=0.7cm, R =170cm, b = 8.5 105 and assuming no constant phase shift during reflection). 4. Comparison of experimental...DW2A.19.pdf Digital Holography and 3D Imaging Technical Digest ©2013 OSA Oil on the water characterization with coherent fringe projection and digital

  2. Superresolution of interference fringes in parallel four-step phase-shifting digital holography.

    PubMed

    Tahara, Tatsuki; Lee, Yonghee; Ito, Yasunori; Xia, Peng; Shimozato, Yuki; Takahashi, Yuki; Awatsuji, Yasuhiro; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2014-03-15

    A superresolution method for interference fringes obtained by parallel four-step phase-shifting digital holography is proposed. A complex amplitude distribution of an object wave is derived from a recorded hologram by parallel phase-shifting interferometry using two pixels without any interpolation procedures. Multiple distributions are derived by changing one of the two pixels when conducting phase-shifting interferometry. The angular spectrum distribution of the object wave is obtained by both the Fourier transforms and synthesis of the spectrum distribution from the Fourier-transformed images in the spatial frequency domain. Available space bandwidth is extended to half of that of an image sensor.

  3. First On-Sky Fringes with an Up-Conversion Interferometer Tested on a Telescope Array

    NASA Astrophysics Data System (ADS)

    Darré, P.; Baudoin, R.; Gomes, J.-T.; Scott, N. J.; Delage, L.; Grossard, L.; Sturmann, J.; Farrington, C.; Reynaud, F.; Brummelaar, T. A. Ten

    2016-12-01

    The Astronomical Light Optical Hybrid Analysis project investigates the combined use of a telescope array interferometer and nonlinear optics to propose a new generation of instruments dedicated to high-resolution imaging for infrared astronomy. The nonlinear process of optical frequency conversion transfers the astronomical light to a shorter wavelength domain. Here, we report on the first fringes obtained on the sky with the prototype operated at 1.55 μ m in the astronomical H band and implemented on the Center for High Angular Resolution Astronomy telescope array. This seminal result allows us to foresee a future extension to the challenging midinfrared spectral domain.

  4. Image aberrations in optical three-dimensional measurement systems with fringe projection.

    PubMed

    Brakhage, Peter; Notni, Gunther; Kowarschik, Richard

    2004-06-01

    In optical shape measurement systems, systematic errors appear as a result of imaging aberrations of the lens assemblies in the cameras and projectors. A mathematical description of this effect is intended to correct the whole measurement area with a few independent coefficients. We apply the ideas of photogrammetry to one- and two-dimensional fringe projection techniques. We also introduce some new terms for close-range applications and telecentric objectives. Further, an algorithm for distance-dependent corrections is introduced. Also, we describe a new method with which to determine coefficients of aberration with an optimization-based method.

  5. Large-angle and high-efficiency tunable phase grating using fringe field switching liquid crystal.

    PubMed

    Xu, Daming; Tan, Guanjun; Wu, Shin-Tson

    2015-05-04

    We propose a switchable phase grating using fringe field switching (FFS) cells. The FFS phase grating possesses several attractive features: large diffraction angle, high diffraction efficiency, fast response time, and high contrast ratio. It can diffract >32% light to ± 2nd orders with a large diffraction angle of 12.1°. Meanwhile, its response time remains relatively fast even at -40°C. A simulation model is developed to explain the experimental results and good agreement is obtained. We also demonstrate a blazed phase grating to achieve tunable beam steering between 0th, 1st and 2nd orders.

  6. Phase-object detection by use of double-exposure fringe-modulated speckle patterns.

    PubMed

    Tebaldi, Myrian; Angel, Luciano; Trivi, Marcelo; Bolognini, Néstor

    2003-01-01

    We study the properties of a double-exposure image specklegram of a diffuse object obtained by use of a double-aperture pupil. A phase object is placed in front of one aperture during the first or the second exposure. Also, it is assumed that a uniform displacement of the diffuser between exposures is produced. The recorded specklegram is coherently illuminated and analyzed by Fourier transform operations. The average intensity distribution and the interference fringe visibility in the Fourier plane are investigated. On this basis, an alternative interference technique to detect phase objects is proposed.

  7. Dynamical Effects Due to Fringe Field of the Magnets in Circular Accelerators

    SciTech Connect

    Cai, Y.; Nosochkov, Yu.; /SLAC

    2005-05-16

    The leading Lie generators, including the chromatic effects, due to hard-edge fringe field of single multipole and solenoid are derived from the vector potentials within a Hamiltonian system. These nonlinear generators are applied to the interaction region of PEP-II to analyze the linear errors due to the feed-down from the off-centered quadrupoles and solenoid. The nonlinear effects of tune shifts at large amplitude, the synchro-betatron sidebands near half integer and their impacts on the dynamic aperture are studied in the paper.

  8. Two-dimensional phase unwrapping algorithms for fringe pattern analysis: a comparison study

    NASA Astrophysics Data System (ADS)

    Yang, Fang; Wang, Zhaomin; Wen, Yongfu; Qu, Weijuan

    2015-03-01

    Phase unwrapping is a process to reconstruct the absolute phase from a wrapped phase map whose range is (-π, π]. As the absolute phase cannot be directly extracted from the fringe pattern, phase unwrapping is therefore required by phasemeasure techniques. Currently, many phase unwrapping algorithms have been proposed. In this paper, four popular phase unwrapping algorithms, including the Goldstein's branch cut method, the quality-guided method, the Phase Unwrapping via Max Flow (PUMA) method, and the phase estimation using adaptive regularization based on local smoothing method (PERALS), are reviewed and discussed. Detailed accuracy comparisons of these methods are provided as well.

  9. Investigation of phase error correction for digital sinusoidal phase-shifting fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Ma, S.; Quan, C.; Zhu, R.; Tay, C. J.

    2012-08-01

    Digital sinusoidal phase-shifting fringe projection profilometry (DSPFPP) is a powerful tool to reconstruct three-dimensional (3D) surface of diffuse objects. However, a highly accurate profile is often hindered by nonlinear response, color crosstalk and imbalance of a pair of digital projector and CCD/CMOS camera. In this paper, several phase error correction methods, such as Look-Up-Table (LUT) compensation, intensity correction, gamma correction, LUT-based hybrid method and blind phase error suppression for gray and color-encoded DSPFPP are described. Experimental results are also demonstrated to evaluate the effectiveness of each method.

  10. First On-Sky Fringes with an Up-Conversion Interferometer Tested on a Telescope Array.

    PubMed

    Darré, P; Baudoin, R; Gomes, J-T; Scott, N J; Delage, L; Grossard, L; Sturmann, J; Farrington, C; Reynaud, F; Brummelaar, T A Ten

    2016-12-02

    The Astronomical Light Optical Hybrid Analysis project investigates the combined use of a telescope array interferometer and nonlinear optics to propose a new generation of instruments dedicated to high-resolution imaging for infrared astronomy. The nonlinear process of optical frequency conversion transfers the astronomical light to a shorter wavelength domain. Here, we report on the first fringes obtained on the sky with the prototype operated at 1.55  μm in the astronomical H band and implemented on the Center for High Angular Resolution Astronomy telescope array. This seminal result allows us to foresee a future extension to the challenging midinfrared spectral domain.

  11. Carbon Nanostructure Examined by Lattice Fringe Analysis of High Resolution Transmission Electron Microscopy Images

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Tomasek, Aaron J.; Street, Kenneth; Thompson, William K.

    2002-01-01

    The dimensions of graphitic layer planes directly affect the reactivity of soot towards oxidation and growth. Quantification of graphitic structure could be used to develop and test correlations between the soot nanostructure and its reactivity. Based upon transmission electron microscopy images, this paper provides a demonstration of the robustness of a fringe image analysis code for determining the level of graphitic structure within nanoscale carbon, i.e. soot. Results, in the form of histograms of graphitic layer plane lengths, are compared to their determination through Raman analysis.

  12. Carbon Nanostructure Examined by Lattice Fringe Analysis of High Resolution Transmission Electron Microscopy Images

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Tomasek, Aaron J.; Street, Kenneth; Thompson, William K.; Hull, David R.

    2003-01-01

    The dimensions of graphitic layer planes directly affect the reactivity of soot towards oxidation and growth. Quantification of graphitic structure could be used to develop and test correlations between the soot nanostructure and its reactivity. Based upon transmission electron microscopy images, this paper provides a demonstration of the robustness of a fringe image analysis code for determining the level of graphitic structure within nanoscale carbon, i.e., soot. Results, in the form of histograms of graphitic layer plane lengths, are compared to their determination through Raman analysis.

  13. Fringe-free, Background-free, Collinear Third Harmonic Generation FROG Measurements for Multiphoton Microscopy

    SciTech Connect

    Chadwick, R; Spahr, E; Squier, J A; Durfee, C G; Walker, B C; Fittinghoff, D N

    2006-07-21

    Collinear pulse measurement tools useful at the full numerical aperture (NA) of multiphoton microscope objectives are a necessity for a quantitative characterization of the femtosecond pulses focused by these systems. In this letter, we demonstrate a simple new technique, for characterizing the pulse at the focus in a multiphoton microscope. This technique, a background-free, fringe-free, form of frequency-resolved optical gating, uses the third harmonic signal generated from a glass coverslip. Here it is used to characterize 100 fs pulses (typical values for a multiphoton microscope) at the focus of a 0.65 NA objective.

  14. Special features of Newton-type fringe formation in a diffraction interferometer

    SciTech Connect

    Koronkevich, Voldemar P.; Lenkova, Galina A.; Matochkin, Aleksey E

    2006-01-01

    An interferometer with a Fresnel zone plate located in the center of curvature of a concave mirror was studied. Attention was paid to the unique features of the interference field, which has a special point at which the path difference is equal to zero, thereby allowing for the observation of Newton-type fringes in white and quasi-monochromatic light. The conditions necessary for reducing the instrumental error to values less than lambda/20 were determined. Methods for suppressing noise and destructive interference patterns were also found. Metrological tests were carried out, and they proved the possibility of using this interferometer for industrial testing of spherical and parabolic mirrors.

  15. Fringe jump analysis and implementation of polarimetry on the ASDEX Upgrade DCN interferometer

    SciTech Connect

    Mlynek, A. Casali, L.; Eixenberger, H.; Ford, O.

    2014-11-15

    The ASDEX Upgrade tokamak is equipped with a 5-channel DCN interferometer with a probing wavelength of 195 μm. Up to now, phase measurement and density calculation have been accomplished by hard-wired phase counting electronics. Meanwhile, a fast digitizer has been installed which acquires the raw signals. That way, the various causes of counting errors by integer multiples of 2π, so-called fringe jumps, can be analyzed, and phase reconstruction schemes based on digital signal processing can be developed. In addition, a prototype polarimeter setup has been installed on one channel and allows for measurement of the Faraday rotation experienced by the probing beam.

  16. KISMET tungsten dispersal experiment

    SciTech Connect

    Wohletz, K.; Kunkle, T.; Hawkins, W.

    1996-12-01

    Results of the KISMET tungsten dispersal experiment indicate a relatively small degree of wall-rock contamination caused by this underground explosive experiment. Designed as an add-on to the KISMET test, which was performed in the U-1a.02 drift of the LYNER facility at Nevada Test Site on 1 March 1995, this experiment involved recovery and analysis of wall-rock samples affected by the high- explosive test. The chemical, high-explosive blast drove tungsten powder, placed around the test package as a plutonium analog, into the surrounding wall- rock alluvium. Sample analyses by an analytical digital electron microscope (ADEM) show tungsten dispersed in the rock as tiny (<10 {mu}m) particles, agglomerates, and coatings on alluvial clasts. Tungsten concentrations, measured by energy dispersive spectral analysis on the ADEM, indicate penetration depths less than 0.1 m and maximum concentrations of 1.5 wt % in the alluvium.

  17. Three-dimensional displacement fields measured in a deforming granular-media surface by combined fringe projection and speckle photography

    NASA Astrophysics Data System (ADS)

    Barrientos, B.; Cerca, M.; García-Márquez, J.; Hernández-Bernal, C.

    2008-10-01

    3D displacement fields on a diffuse surface are measured by a combination of two optical methods, fringe projection and speckle photography. The use of a single camera for recording information from the two methods implies that no calibration procedures are necessary, as is the case in stereoscopy-based techniques. Out-of-plane displacements are measured by fringe projection whereas speckle photography yields the 2D in-plane component. By using this technique, we analyze in detail the morphological spatial-temporal evolution of an analogue model of the Earth's crust while subjected to compression forces. We discuss the experimental results and their relevance to the micromechanics of a surface of dry, non-cohesive and dilatant granular media. The results show that the combination of fringe projection and speckle photography is well suited for this type of study and allows the characterization of strain at the grain scale.

  18. Electro-optic characteristics of 90° twisted nematic liquid crystal display driven by fringe-electric field

    NASA Astrophysics Data System (ADS)

    Song, I. S.; Shin, S. S.; Kim, H. Y.; Song, S. H.; Lee, S. H.

    2004-02-01

    We investigated the electro-optic characteristics of a fringe-field driven twisted nematic (TN) display. In the absence of an electric field, the liquid crystals (LCs) are initially twisted 90° from the top to the bottom substrate under parallel polarizers so that the cell appears to be black. In the presence of a fringe-electric field, the LCs with negative dielectric anisotropy are rotated toward a plane that is almost perpendicular to the horizontal component of the fringe field, above the entire electrode surface. The cell then appears to be white, and shows high transmittance. In addition, the cell displays a wide viewing angle and has excellent color characteristics over a wide viewing range due to almost in-plane switching, unlike a conventional TN device where the LC director tilts upward in only one direction and results in a narrow viewing angle.

  19. Strain distribution in an Si single crystal measured by interference fringes of X-ray mirage diffraction.

    PubMed

    Jongsukswat, Sukswat; Fukamachi, Tomoe; Ju, Dongying; Negishi, Riichirou; Hirano, Keiichi; Kawamura, Takaaki

    2013-10-01

    In X-ray interference fringes accompanied by mirage diffraction, variations have been observed in the spacing and position of the fringes from a plane-parallel Si single crystal fixed at one end as a function of distance from the incident plane of the X-rays to the free crystal end. The variations can be explained by distortion of the sample crystal due to gravity. From the variations and positions of the fringes, the strain gradient of the crystal has been determined. The distribution of the observed strain agrees with that expected from rod theory except for residual strain. When the distortion is large, the observed strain distribution does not agree with that expected from rod theory.

  20. Effective elimination of laser interference fringing in fluorescence microscopy by spinning azimuthal incidence angle.

    PubMed

    Mattheyses, Alexa L; Shaw, Keith; Axelrod, Daniel

    2006-08-01

    Laser illumination used in both conventional widefield epi-fluorescence as well as in total internal reflection fluorescence (TIRF) microscopy is subject to nonuniformities in intensity that obscure true image details. These intensity variations are interference fringes arising from coherent light scattering and diffraction at every surface in the laser light's optical path, including the lenses, mirrors, and coverslip. We present an inexpensive technique for effectively eliminating these interference fringes based upon introduction of the excitation laser beam by oblique through-the-objective incidence coupled with rapid azimuthal rotation of the plane of incidence. Although this rotation can be accomplished in several ways, a particularly simple method applicable to a free laser beam is to use an optical wedge, spun on a motor, which diverts the beam into a hollow cone of fixed angle. A system of lenses converts this collimated beam cone into a focused spot that traces a circle at the objective's back focal plane. Consequently, a collimated beam with fixed polar angle and spinning azimuthal angle illuminates the sample. If the wedge is spun rapidly, then the different interference patterns at every particular azimuthal incidence angle average out over a single camera exposure to produce an effectively uniform field of illumination.