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Sample records for fringe sensor unit

  1. The PRIMA Fringe Sensor Unit

    CERN Document Server

    Sahlmann, Johannes; Abuter, Roberto; Accardo, Matteo; Mottini, Sergio; Delplancke, Francoise

    2009-01-01

    The Fringe Sensor Unit (FSU) is the central element of the Phase Referenced Imaging and Micro-arcsecond Astrometry (PRIMA) dual-feed facility and provides fringe sensing for all observation modes, comprising off-axis fringe tracking, phase referenced imaging, and high-accuracy narrow-angle astrometry. It is installed at the Very Large Telescope Interferometer (VLTI) and successfully servoed the fringe tracking loop during the initial commissioning phase. Unique among interferometric beam combiners, the FSU uses spatial phase modulation in bulk optics to retrieve real-time estimates of fringe phase after spatial filtering. A R=20 spectrometer across the K-band makes the retrieval of the group delay signal possible. The FSU was integrated and aligned at the VLTI in summer 2008. It yields phase and group delay measurements at sampling rates up to 2 kHz, which are used to drive the fringe tracking control loop. During the first commissioning runs, the FSU was used to track the fringes of stars with K-band magnitu...

  2. First results from fringe tracking with the PRIMA fringe sensor unit

    CERN Document Server

    Sahlmann, J; Menardi, S; Schmid, C; Di Lieto, N; Delplancke, F; Frahm, R; Gomes, N; Haguenauer, P; Leveque, S; Morel, S; Mueller, A; Duc, T Phan; Schuhler, N; van Belle, G; 10.1117/12.856896

    2010-01-01

    The fringe sensor unit (FSU) is the central element of the phase referenced imaging and micro-arcsecond astrometry (PRIMA) dual-feed facility for the Very Large Telescope interferometer (VLTI). It has been installed at the Paranal observatory in August 2008 and is undergoing commissioning and preparation for science operation. Commissioning observations began shortly after installation and first results include the demonstration of spatially encoded fringe sensing and the increase in VLTI limiting magnitude for fringe tracking. However, difficulties have been encountered because the FSU does not incorporate real-time photometric correction and its fringe encoding depends on polarisation. These factors affect the control signals, especially their linearity, and can disturb the tracking control loop. To account for this, additional calibration and characterisation efforts are required. We outline the instrument concept and give an overview of the commissioning results obtained so far. We describe the effects of...

  3. Dispersed fringe sensor for the Giant Magellan Telescope.

    Science.gov (United States)

    van Dam, Marcos A; McLeod, Brian A; Bouchez, Antonin H

    2016-01-20

    The Giant Magellan Telescope (GMT) consists of seven 8.365 m segments, with gaps of 0.345 m between adjacent segments. A unique challenge for GMT lies in phasing the segments and, in particular, how to measure segment piston optically while the telescope is in science operation. In this paper, we present a dispersed fringe sensor (DFS) to make these measurements using a novel algorithm. We show that using four off-axis DFSs operating at J-band with 10 ms exposures, we are able to measure segment piston to the required 50 nm accuracy every 30 s with over 90% sky coverage.

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

    Science.gov (United States)

    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.

  5. Fast in-situ tool inspection based on inverse fringe projection and compact sensor heads

    Science.gov (United States)

    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.

  6. A microfabricated fringing field capacitive pH sensor with an integrated readout circuit

    Energy Technology Data Exchange (ETDEWEB)

    Arefin, Md Shamsul, E-mail: md.arefin@monash.edu; Redoute, Jean-Michel; Rasit Yuce, Mehmet [Electrical and Computer Systems Engineering, Monash University, Melbourne (Australia); Bulut Coskun, M.; Alan, Tuncay; Neild, Adrian [Mechanical and Aerospace Engineering, Monash University, Melbourne (Australia)

    2014-06-02

    This work presents a microfabricated fringe-field capacitive pH sensor using interdigitated electrodes and an integrated modulation-based readout circuit. The changes in capacitance of the sensor result from the permittivity changes due to pH variations and are converted to frequency shifts using a crossed-coupled voltage controlled oscillator readout circuit. The shift in resonant frequency of the readout circuit is 30.96 MHz for a change in pH of 1.0–5.0. The sensor can be used for the measurement of low pH levels, such as gastric acid, and can be integrated with electronic pills. The measurement results show high repeatability, low noise, and a stable output.

  7. Fast processing of optical fringe movement in displacement sensors without using an ADC

    Science.gov (United States)

    Hussain, Babar; Muhammad, Taj; Rehan, Muhammad; Aman, Haroon; Aslam, Muhammad; Ikram, Masroor; Raja, M. Yasin Akhtar

    2013-09-01

    An interferometer based optical sensor for displacement measurement is reported. This method requires quite simple signal processing as well as least electronic components. Referring to this technique, two photodiodes spatially shifted by 90 degrees were used. The output of photodiodes was converted into rectangular signals which were extracted in LabVIEW using the data acquisition card without using an analog to digital converters (ADC). We have also processed the signals in C++ after acquiring via parallel port. A Michelson interferometer configuration was used to produce linear fringes for the detection of displacements. The displacement less than 100 nm could be measured using this technique.

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

    Science.gov (United States)

    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. Topographical features of physiographic unit borders on reef flat in fringing reefs

    OpenAIRE

    Nakai, Tatsuo

    2007-01-01

    In coral reef ecosystem spatial structure of 10^1-10^3m scale provide very important aspect in coral reef conservation. Nakai (2007) showed that physiographic unit (PGU) could be set as well as zonation on reef flat of fringing reef. The borders of PGUs delimiting it from the open sea or an adjacent PGU are constituted by landforms such as reef crest or channels. In this article the landforms becoming the borders of PGUs were discussed and the PGU property was clarified.

  10. An improved sensor for precision detection of in situ stem water content using a frequency domain fringing capacitor.

    Science.gov (United States)

    Zhou, Haiyang; Sun, Yurui; Tyree, Melvin T; Sheng, Wenyi; Cheng, Qiang; Xue, Xuzhang; Schumann, Henrik; Schulze Lammers, Peter

    2015-04-01

    One role of stems is that of water storage. The water content of stems increases and decreases as xylem water potential increases and decreases, respectively. Hence, a nondestructive method to measure stem water content (StWC) = (volume of water) : (volume of stem), could be useful in monitoring the drought stress status of plants. We introduce a frequency domain inner fringing capacitor-sensor for measuring StWC which operates at 100 MHz frequency. The capacitor-sensor consists of two wave guides (5-mm-wide braided metal) that snugly fit around the surface of a stem with a spacing of 4-5 mm between guides. Laboratory measurements on analog stems reveals that the DC signal output responds linearly to the relative dielectric constant of the analog stem, is most sensitive to water content between the waveguides to a depth of c. 3 mm from the stem surface, and calibrations based on the gravimetric water loss of excised stems of plants revealed a resolution in StWC of < ± 0.001 v/ v. The sensor performed very well on whole plants with a 100-fold increased resolution compared with previous frequency domain and time domain reflectometry methods and, hence, may be very useful for future research requiring nondestructive measurements of whole plants. © European Union 2014. New Phytologist © 2014 New Phytologist Trust.

  11. Inertial measurement unit using rotatable MEMS sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Stewart M.; Allen, James J.

    2006-06-27

    A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator for drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows, for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.

  12. Inertial measurement unit using rotatable MEMS sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Stewart M. (Albuquerque, NM); Allen, James J. (Albuquerque, NM)

    2007-05-01

    A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.

  13. Inertial measurement unit using rotatable MEMS sensors

    Science.gov (United States)

    Kohler, Stewart M.; Allen, James J.

    2007-05-01

    A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.

  14. Hierarchical fringe tracking

    CERN Document Server

    Petrov, Romain G; Boskri, Abdelkarim; Folcher, Jean-Pierre; Lagarde, Stephane; Bresson, Yves; Benkhaldoum, Zouhair; Lazrek, Mohamed; Rakshit, Suvendu

    2014-01-01

    The limiting magnitude is a key issue for optical interferometry. Pairwise fringe trackers based on the integrated optics concepts used for example in GRAVITY seem limited to about K=10.5 with the 8m Unit Telescopes of the VLTI, and there is a general "common sense" statement that the efficiency of fringe tracking, and hence the sensitivity of optical interferometry, must decrease as the number of apertures increases, at least in the near infrared where we are still limited by detector readout noise. Here we present a Hierarchical Fringe Tracking (HFT) concept with sensitivity at least equal to this of a two apertures fringe trackers. HFT is based of the combination of the apertures in pairs, then in pairs of pairs then in pairs of groups. The key HFT module is a device that behaves like a spatial filter for two telescopes (2TSF) and transmits all or most of the flux of a cophased pair in a single mode beam. We give an example of such an achromatic 2TSF, based on very broadband dispersed fringes analyzed by g...

  15. A Self-Powered and Autonomous Fringing Field Capacitive Sensor Integrated into a Micro Sprinkler Spinner to Measure Soil Water Content

    Directory of Open Access Journals (Sweden)

    Eduardo Ferreira da Costa

    2017-03-01

    Full Text Available We present here the design and fabrication of a self-powered and autonomous fringing field capacitive sensor to measure soil water content. The sensor is manufactured using a conventional printed circuit board and includes a porous ceramic. To read the sensor, we use a circuit that includes a 10 kHz triangle wave generator, an AC amplifier, a precision rectifier and a microcontroller. In terms of performance, the sensor’s capacitance (measured in a laboratory prototype increases up to 5% when the volumetric water content of the porous ceramic changed from 3% to 36%, resulting in a sensitivity of S = 15.5 pF per unity change. Repeatability tests for capacitance measurement showed that the θ v sensor’s root mean square error is 0.13%. The average current consumption of the system (sensor and signal conditioning circuit is less than 1.5 μ A, which demonstrates its suitability for being powered by energy harvesting systems. We developed a complete irrigation control system that integrates the sensor, an energy harvesting module composed of a microgenerator installed on the top of a micro sprinkler spinner, and a DC/DC converter circuit that charges a 1 F supercapacitor. The energy harvesting module operates only when the micro sprinkler spinner is irrigating the soil, and the supercapacitor is fully charged to 5 V in about 3 h during the first irrigation. After the first irrigation, with the supercap fully charged, the system can operate powered only by the supercapacitor for approximately 23 days, without any energy being harvested.

  16. A Self-Powered and Autonomous Fringing Field Capacitive Sensor Integrated into a Micro Sprinkler Spinner to Measure Soil Water Content

    Science.gov (United States)

    da Costa, Eduardo Ferreira; de Oliveira, Nestor E.; Morais, Flávio J. O.; Carvalhaes-Dias, Pedro; Duarte, Luis Fernando C.; Cabot, Andreu; Siqueira Dias, J. A.

    2017-01-01

    We present here the design and fabrication of a self-powered and autonomous fringing field capacitive sensor to measure soil water content. The sensor is manufactured using a conventional printed circuit board and includes a porous ceramic. To read the sensor, we use a circuit that includes a 10 kHz triangle wave generator, an AC amplifier, a precision rectifier and a microcontroller. In terms of performance, the sensor’s capacitance (measured in a laboratory prototype) increases up to 5% when the volumetric water content of the porous ceramic changed from 3% to 36%, resulting in a sensitivity of S=15.5 pF per unity change. Repeatability tests for capacitance measurement showed that the θv sensor’s root mean square error is 0.13%. The average current consumption of the system (sensor and signal conditioning circuit) is less than 1.5 μA, which demonstrates its suitability for being powered by energy harvesting systems. We developed a complete irrigation control system that integrates the sensor, an energy harvesting module composed of a microgenerator installed on the top of a micro sprinkler spinner, and a DC/DC converter circuit that charges a 1 F supercapacitor. The energy harvesting module operates only when the micro sprinkler spinner is irrigating the soil, and the supercapacitor is fully charged to 5 V in about 3 h during the first irrigation. After the first irrigation, with the supercap fully charged, the system can operate powered only by the supercapacitor for approximately 23 days, without any energy being harvested. PMID:28287495

  17. Sensor concentrator unit for the Continuous Automated Vault Inventory System

    Energy Technology Data Exchange (ETDEWEB)

    Nodine, R.N.; Lenarduzzi, R.

    1997-06-01

    The purpose of this document is to describe the use and operation of the sensor concentrator in the Continuous Automated Vault Inventory System (CAVIS). The CAVIS electronically verifies the presence of items of stored special nuclear material (SNM). US Department of Energy orders require that stored SNM be inventoried periodically to provide assurance that the material is secure. Currently this inventory is a highly manual activity, requiring personnel to enter the storage vaults. Using a CAVIS allows the frequency of physical inventories to be significantly reduced, resulting in substantial cost savings, increased security, and improved safety. The electronic inventory of stored SNM requires two different types of sensors for each item. The two sensors measure different parameters of the item, usually weight and gamma rays. A CAVIS is constructed using four basic system components: sensors, sensor concentrators, a data collection unit, and a database/user interface unit. One sensor concentrator supports the inventory of up to 20 items (40 sensors) and continuously takes readings from the item sensors. On request the sensor concentrator outputs the most recent sensor readings to the data collection unit. The information transfer takes place over a RS485 communications link. The data collection unit supports from 1 to 120 sensor concentrators (1 to 2,400 items) and is referred to as the Sensor Polling and Configuration System (SPCS). The SPCS is connected by a secure Transmission Control Protocol/Internet Protocol (TCP/IP) network to the database/user interface unit, which is referred to as the Graphical Facility Information Center (GraFIC). A CAVIS containing more than 2,400 items is supported by connecting additional SPCS units to the GraFIC.

  18. Sensor concentrator unit for the Continuous Automated Vault Inventory System

    Energy Technology Data Exchange (ETDEWEB)

    Nodine, R.N.; Lenarduzzi, R.

    1997-06-01

    The purpose of this document is to describe the use and operation of the sensor concentrator in the Continuous Automated Vault Inventory System (CAVIS). The CAVIS electronically verifies the presence of items of stored special nuclear material (SNM). US Department of Energy orders require that stored SNM be inventoried periodically to provide assurance that the material is secure. Currently this inventory is a highly manual activity, requiring personnel to enter the storage vaults. Using a CAVIS allows the frequency of physical inventories to be significantly reduced, resulting in substantial cost savings, increased security, and improved safety. The electronic inventory of stored SNM requires two different types of sensors for each item. The two sensors measure different parameters of the item, usually weight and gamma rays. A CAVIS is constructed using four basic system components: sensors, sensor concentrators, a data collection unit, and a database/user interface unit. One sensor concentrator supports the inventory of up to 20 items (40 sensors) and continuously takes readings from the item sensors. On request the sensor concentrator outputs the most recent sensor readings to the data collection unit. The information transfer takes place over a RS485 communications link. The data collection unit supports from 1 to 120 sensor concentrators (1 to 2,400 items) and is referred to as the Sensor Polling and Configuration System (SPCS). The SPCS is connected by a secure Transmission Control Protocol/Internet Protocol (TCP/IP) network to the database/user interface unit, which is referred to as the Graphical Facility Information Center (GraFIC). A CAVIS containing more than 2,400 items is supported by connecting additional SPCS units to the GraFIC.

  19. Foot Pose Estimation Using an Inertial Sensor Unit and Two Distance Sensors

    Directory of Open Access Journals (Sweden)

    Pham Duy Duong

    2015-07-01

    Full Text Available There are many inertial sensor-based foot pose estimation algorithms. In this paper, we present a methodology to improve the accuracy of foot pose estimation using two low-cost distance sensors (VL6180 in addition to an inertial sensor unit. The distance sensor is a time-of-flight range finder and can measure distance up to 20 cm. A Kalman filter with 21 states is proposed to estimate both the calibration parameter (relative pose of distance sensors with respect to the inertial sensor unit and foot pose. Once the calibration parameter is obtained, a Kalman filter with nine states can be used to estimate foot pose. Through four activities (walking, dancing step, ball kicking, jumping, it is shown that the proposed algorithm significantly improves the vertical position estimation.

  20. Low-Cost Sensor Units for Measuring Urban Air Quality

    Science.gov (United States)

    Popoola, O. A.; Mead, M.; Stewart, G.; Hodgson, T.; McLoed, M.; Baldovi, J.; Landshoff, P.; Hayes, M.; Calleja, M.; Jones, R.

    2010-12-01

    Measurements of selected key air quality gases (CO, NO & NO2) have been made with a range of miniature low-cost sensors based on electrochemical gas sensing technology incorporating GPS and GPRS for position and communication respectively. Two types of simple to operate sensors units have been designed to be deployed in relatively large numbers. Mobile handheld sensor units designed for operation by members of the public have been deployed on numerous occasions including in Cambridge, London and Valencia. Static sensor units have also been designed for long-term autonomous deployment on existing street furniture. A study was recently completed in which 45 sensor units were deployed in the Cambridge area for a period of 3 months. Results from these studies indicate that air quality varies widely both spatially and temporally. The widely varying concentrations found suggest that the urban environment cannot be fully understood using limited static site (AURN) networks and that a higher resolution, more dispersed network is required to better define air quality in the urban environment. The results also suggest that higher spatial and temporal resolution measurements could improve knowledge of the levels of individual exposure in the urban environment.

  1. Finite fringe hologram

    Science.gov (United States)

    Heflinger, L. O.

    1970-01-01

    In holographic interferometry a small movement of apparatus between exposures causes the background of the reconstructed scene to be covered with interference fringes approximately parallel to each other. The three-dimensional quality of the holographic image is allowable since a mathematical model will give the location of the fringes.

  2. A mobile Magnetic Sensor Unit for the KATRIN Main Spectrometer

    CERN Document Server

    Osipowicz, A; Letnev, J; Marte, P; Müller, A; Spengler, A; Unru, A; 10.1088/1748-0221/7/06/T06002

    2012-01-01

    The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to measure the electron neutrino mass with an unprecedented sensitivity of 0.2 eV/c2, using b decay electrons from tritium decay. For the control of magnetic field in the main spectrometer area of the KATRIN experiment a mobile magnetic sensor unit is constructed and tested at the KATRIN main spectrometer site. The unit moves on inner rails of the support structures of the low field shaping coils which are arranged along the the main spectrometer. The unit propagates on a caterpillar drive and contains an electro motor, battery pack, board electronics, 2 triaxial flux gate sensors and 2 inclination senors. During operation all relevant data are stored on board and transmitted to the master station after the docking station is reached.

  3. New radiation sensor embedded in a metal detection unit

    Energy Technology Data Exchange (ETDEWEB)

    Osovizky, A.; Cohen-Zada, I.; Vulasky, E.; Ginzburg, D.; Manor, A.; Ankry, N.; Pushkarsky, V.; Lefevre, M. [Health Physics Instrumentation Department, Rotem Industries Ltd. (Israel); Ghelman, M.; Marcus, E.; Kadmon, Y.; Cohen, Y. [Electronics and Control Laboratories, Nuclear Research Center - Negev, Beer-Sheva (Israel)

    2009-07-01

    This work introduces the embedment of a radiation detection unit within a metal detector. The radiation sensor, based on the Silicon Photomultiplier (SiPM) coupled to a scintillation crystal, was successfully incorporated into a common metal detection unit. The results for sensitivity are presented. The study also shows that SiPM is not affected by microphone noises (which make PIN-diodes improper to some applications) and by the alternating type of the voltage supply (which means that SiPM can be used either in portable or in stationary applications)

  4. An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs

    Directory of Open Access Journals (Sweden)

    Ching-Hsing Luo

    2011-07-01

    Full Text Available In this work, an asynchronous multi-sensor micro control unit (MCU core is proposed for wireless body sensor networks (WBSNs. It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE, and an error correct coder (ECC. To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs.

  5. 77 FR 42419 - Airworthiness Directives; Honeywell International, Inc. Global Navigation Satellite Sensor Units

    Science.gov (United States)

    2012-07-19

    ... International, Inc. Global Navigation Satellite Sensor Units AGENCY: Federal Aviation Administration (FAA), DOT... augmentation system (WAAS) global navigation satellite sensor units (GNSSU). This AD requires you cease all... positioning system (GPS) sensor and the same software as the Model KGS200 Mercury\\2\\ GNSSU. A software problem...

  6. Fringe Mind Strategies

    NARCIS (Netherlands)

    Sleutels, J.J.M.

    2013-01-01

    This paper discusses a number of basic strategies for modeling the mind in historical perspective. The best-known strategies are expansionism and eliminativism, which are both problematic: eliminativism compromises our self-understanding, while expansionism is unable to cope with fringe minds. Using

  7. Fringe Mind Strategies

    Directory of Open Access Journals (Sweden)

    Jan Sleutels

    2013-09-01

    Full Text Available This paper discusses a number of basic strategies for modeling the mind in historical perspective. The best-known strategies are expansionism and eliminativism, which are both problematic: eliminativism compromises our self-understanding, while expansionism is unable to cope with fringe minds. Using Julian Jaynes’s theory of the bicameral mind as an example, an alternative strategy is outlined to meet the challenges posed by the history of the mind.

  8. Fringing in MonoCam Y4 filter images

    Science.gov (United States)

    Brooks, J.; Fisher-Levine, M.; Nomerotski, A.

    2017-05-01

    We study the fringing patterns observed in MonoCam, a camera with a single Large Synoptic Survey Telescope (LSST) CCD sensor. Images were taken at the U.S. Naval Observatory in Flagstaff, Arizona (NOFS) employing its 1.3 m telescope and an LSST y4 filter. Fringing occurs due to the reflection of infrared light (700 nm or larger) from the bottom surface of the CCD which constructively or destructively interferes with the incident light to produce a net ``fringe'' pattern which is superimposed on all images taken. Emission lines from the atmosphere, dominated by hydroxyl (OH) spectra, can change in their relative intensities as the night goes on, producing different fringe patterns in the images taken. We found through several methods that the general shape of the fringe patterns remained constant, though with slight changes in the amplitude and phase of the fringes. We also found that a superposition of fringes from two monochromatic lines taken in the lab offered a reasonable description of the sky data.

  9. Method for sensing an analyte in a fluid and sensor unit for such method

    NARCIS (Netherlands)

    Dekker, N.H.; Pedaci, F.; Barland, S.

    2012-01-01

    The invention provides a method for sensing with a sensor system an analyte in an analyte fluid. The sensor system comprises a micron scale birefringent entity, a laser unit configured to generate polarized laser light, a polarization rotation device, wherein the laser unit and polarization rotation

  10. Endoscopic fringe projection for in-situ inspection of a sheet-bulk metal forming process

    Science.gov (United States)

    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

  11. An interrogation unit for passive wireless SAW sensors based on fourier transform.

    Science.gov (United States)

    Hamsch, Matthias; Hoffmann, Rene; Buff, Werner; Binhack, Michael; Klett, Stefan

    2004-11-01

    The application of surface acoustic wave (SAW) resonators as sensor elements for different physical parameters such as temperature, pressure, and force has been well-known for several years. The energy storage in the SAW and the direct conversion from physical parameter to a parameter of the wave, such as frequency or phase, enables the construction of a passive sensor that can be interrogated wireless. This paper presents a temperature-measurement system based on passive wireless SAW sensors. The principle of SAW sensors and SAW sensor interrogation is discussed briefly. A new measurement device developed for analyzing the sensor signals is introduced. Compared to former interrogation units that detect resonance frequency of the SAW resonator by comparing amplitudes of sensor response signals related to different stimulating frequencies, the new equipment is able to measure the resonance frequency directly by calculating a Fourier transformation of the resonator response signal. Measurement results of an experimental setup and field tests are presented and discussed.

  12. 10 CFR 5.525 - Fringe benefits.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement...

  13. They shall wear fringes.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Theoretical Analysis of Interferometer Wave Front Tilt and Fringe Radiant Flux on a Rectangular Photodetector

    Directory of Open Access Journals (Sweden)

    Franz Konstantin Fuss

    2013-09-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  17. Automatic Fringe Detection Of Dynamic Moire Patterns

    Science.gov (United States)

    Fang, Jing; Su, Xian-ji; Shi, Hong-ming

    1989-10-01

    Fringe-carrier method is used in automatic fringe-order numbering of dynamic in-plane moire patterns. In experiment both static carrier and dynamic moire patterns are recorded. The image files corresponding to instants are set up to assign fringe orders automatically. Subtracting the carrier image from the modulated ones, the moire patterns due to the dynamic deformations are restored with fringe-order variation displayed by different grey levels.

  18. Initial Realization of a Sensor Fusion Based Onboard Maritime Integrated PNT Unit

    Directory of Open Access Journals (Sweden)

    Ralf Ziebold

    2013-03-01

    Full Text Available This paper introduces the basic concept of the Position Navigation and Timing (PNT Module as future part of a ship side Integrated Navigation System (INS. Core of the PNT Module is a sensor fusion based processing system (PNT Unit. The paper will focus on important aspects and first results of the initial practical realization of such a PNT Unit, including a realization of a Consistent Common Reference System (CCRS, GNSS/IMU tightly coupled positioning results as well as contingency performance of the inertial sensors.

  19. Homomorphic partial differential equation filtering method for electronic speckle pattern interferometry fringes based on fringe density

    Institute of Scientific and Technical Information of China (English)

    Fang Zhang; Wenyao Liu; Lin Xia; Jinjiang Wang; Yue Zhu

    2009-01-01

    Noise reduction is one of the most exciting problems in electronic speckle pattern interferometry. We present a homomorphic partial differential equation filtering method for interferometry fringe patterns. The diffusion speed of the equation is determined based on the fringe density. We test the new method on the computer-simulated fringe pattern and experimentally obtain the fringe pattern, and evaluate its filtering performance. The qualitative and quantitative analysis shows that this technique can filter off the additive and multiplicative noise of the fringe patterns effectively, and avoid blurring high-density fringe. It is more capable of improving the quality of fringe patterns than the classical filtering methods.

  20. A dual-mode proximity sensor with integrated capacitive and temperature sensing units

    Science.gov (United States)

    Qiu, Shihua; Huang, Ying; He, Xiaoyue; Sun, Zhiguang; Liu, Ping; Liu, Caixia

    2015-10-01

    The proximity sensor is one of the most important devices in the field of robot application. It can accurately provide the proximity information to assistant robots to interact with human beings and the external environment safely. In this paper, we have proposed and demonstrated a dual-mode proximity sensor composed of capacitive and resistive sensing units. We defined the capacitive type proximity sensor perceiving the proximity information as C-mode and the resistive type proximity sensor detecting as R-mode. Graphene nanoplatelets (GNPs) were chosen as the R-mode sensing material because of its high performance. The dual-mode proximity sensor presents the following features: (1) the sensing distance of the dual-mode proximity sensor has been enlarged compared with the single capacitive proximity sensor in the same geometrical pattern; (2) experiments have verified that the proposed sensor can sense the proximity information of different materials; (3) the proximity sensing capability of the sensor has been improved by two modes perceive collaboratively, for a plastic block at a temperature of 60 °C: the R-mode will perceive the proximity information when the distance d between the sensor and object is 6.0-17.0 mm and the C-mode will do that when their interval is 0-2.0 mm additionally two modes will work together when the distance is 2.0-6.0 mm. These features indicate our transducer is very valuable in skin-like sensing applications.

  1. Improvement of a sensor unit for wrist blood pressure monitoring system

    Science.gov (United States)

    Koo, Sangjun; Kwon, Jongwon; Park, Yongman; Ayuzenara, Odgerel; Kim, Hiesik

    2007-12-01

    A blood pressure sensor unit for ubiquitous healthcare monitoring was newly developed. The digital wrist band-type blood pressure devices for home are popular already in the market. It is useful for checking blood pressure level at home and control of hypertension. Especially, it is very essential home device to check the health condition of blood circulation disease. Nowadays many product types are available. But the measurement of blood pressure is not accurate enough compared with the mechanical type. It needs to be upgraded to assure the precise health data enough to use in the hospital. The structure, feature and output signal of capacitor type pressure sensors are analyzed. An improved design of capacitor sensor is suggested. It shows more precise health data after use on a wrist band type health unit. They can be applied for remote u-health medical service.

  2. Dispersed Fringe Sensing Analysis - DFSA

    Science.gov (United States)

    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

  3. Self-Correcting HVAC Controls: Algorithms for Sensors and Dampers in Air-Handling Units

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Nicholas; Brambley, Michael R.; Katipamula, Srinivas

    2009-12-31

    This report documents the self-correction algorithms developed in the Self-Correcting Heating, Ventilating and Air-Conditioning (HVAC) Controls project funded jointly by the Bonneville Power Administration and the Building Technologies Program of the U.S. Department of Energy. The algorithms address faults for temperature sensors, humidity sensors, and dampers in air-handling units and correction of persistent manual overrides of automated control systems. All faults considered create energy waste when left uncorrected as is frequently the case in actual systems.

  4. The LINC-NIRVANA fringe and flexure tracker control system

    Science.gov (United States)

    Rost, Steffen; Eckart, Andreas; Horrobin, Matthew; Lindhorst, Bettina; Rauch, Christoph; Smajic, Semir; Straubmeier, Christian; Tremou, Evangelia; Wank, Imke; Zuther, Jens; Pott, Jörg-Uwe

    2012-07-01

    We present the latest status of the control system of the LN (LINC-NIRVANA) FFTS (Fringe and Flexure Tracker System) for the LBT. The software concept integrates the sensor data and control of the various subsystems and provides the interaction with the whole LN instrument. Varying conditions and multiple configurations for observations imply a flexible interconnection of the control loops for the hardware manipulators with respect to the time-critical data analysis of the fringe detection. In this contribution details of the implementation of the algorithms on a real-time Linux PC are given. By considering the results from simulations of the system dynamics, lab experiments, atmospheric simulations, and telescope characterization the optimal parameter setup for an observation can be chosen and basic techniques for adaption to changing conditions can be derived.

  5. Development of an Emergency Locking Unit for a Belt-In-Seat (BIS System Using a MEMS Acceleration Sensor

    Directory of Open Access Journals (Sweden)

    Chang Hyun Baek

    2010-04-01

    Full Text Available This paper proposes an emergency locking unit (ELU for a seat belt retractor which is mounted on the back frame of a vehicle seat. The proposed unit uses a recliner sensor based on a MEMS acceleration sensor and solenoid mechanism. The seat has an upper frame supported to tilt on a lower frame. The retractor in belt in seat (BIS system is supported by the upper frame. The proposed recliner sensor based on a MEMS acceleration sensor comprises orientation means for maintaining a predetermined orientation of emergency relative to the lower frame independently of the force of gravity when the upper frame tilts on the lower frame. Experimental results show that the developed recliner sensor unit operates effectively with respect to rollover angles. Thus, the developed unit will have a considerable potential to offer a new design concept in BIS system.

  6. Fringe formation in dual-hologram interferometry

    Science.gov (United States)

    Burner, A. W.

    1990-01-01

    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.

  7. Rezoning of fringe at 105-KE Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Leitz, E.E.

    1960-02-26

    A study was made to determine the optimum arrangement of the fringe flow zones at KE Reactor. Also considered, was the possibility of converting part or all of the existing fringe zone (actually three flow zones) from solid metal to I & E metal to decrease rupture potential in these low flow zones. The necessity for this study was indicated by high tube outlet temperatures in the fringe flow zones and the recent occurrence of two solid metal ruptures in process tubes located in the fringe zone of the reactor. Two additional solid ruptures occurred during the period that conversion to I & E in zone 2, as recommended below, was being completed.

  8. Modulation index optimization for optical fringe suppression in wavelength modulation spectroscopy

    Science.gov (United States)

    Xiong, Bo; Du, Zhenhui; Li, Jinyi

    2015-11-01

    Optical fringes constitute one of the major obstacles in the gas detection based on wavelength modulation spectroscopy (WMS). In order to suppress optical fringes, a convenient method of modulation index optimization was presented, using the signal-fringe ratio as a criterion. In addition to suppressing optical fringes, the optimized modulation index enables the detection of gas absorption. This method was demonstrated in a WMS based oxygen sensor. By comparing the sensor performances with and without the use of the optimized modulation index, we showed that the optical fringes are reduced by using the optimized modulation index; furthermore, the system stability and detection limit are improved. More specifically, the long-term fluctuation of the sensor measurement is dramatically reduced by a factor of 8, and a detection limit of as low as 120 ppm (with effective optical path length of 32 cm and integral time of 2.6 s), characterized by the Allan variance, was derived. This method can be applied in other existing WMS systems without the need for additional devices or complex algorithms and has the potential to be used in both laboratory and industrial settings.

  9. Validation of distal limb mounted inertial-measurement-unit sensors for stride detection in Warmblood horses at walk and trot

    NARCIS (Netherlands)

    Bragança, F M; Bosch, S; Voskamp, J P; Marin-Perianu, M; Van der Zwaag, B J; Vernooij, J C M; van Weeren, P R; Back, W

    2016-01-01

    BACKGROUND: Inertial-measurement-unit (IMU)-sensor-based techniques are becoming more popular in horses as a tool for objective locomotor assessment. OBJECTIVES: To describe, evaluate and validate a method of stride detection and quantification at walk and trot using distal limb mounted IMU-sensors.

  10. Validation of distal limb mounted inertial measurement unit sensors for stride detection in Warmblood horses at walk and trot

    NARCIS (Netherlands)

    Braganca, F.M.; Bosch, Stephan; Voskamp, J.P.; Marin-Perianu, M.; Zwaag, van der B.J.; Vernooij, J.C.; Weeren, van P.R.; Back, W.

    2016-01-01

    Background: Inertial measurement unit (IMU) sensor-based techniques are becoming more popular in horses as a tool for objective locomotor assessment. Objectives: To describe, evaluate and validate a method of stride detection and quantification at walk and trot using distal limb mounted IMU sensors

  11. Community Air Sensor Network (CAIRSENSE) project: evaluation of low-cost sensor performance in a suburban environment in the southeastern United States

    Science.gov (United States)

    Jiao, Wan; Hagler, Gayle; Williams, Ronald; Sharpe, Robert; Brown, Ryan; Garver, Daniel; Judge, Robert; Caudill, Motria; Rickard, Joshua; Davis, Michael; Weinstock, Lewis; Zimmer-Dauphinee, Susan; Buckley, Ken

    2016-11-01

    Advances in air pollution sensor technology have enabled the development of small and low-cost systems to measure outdoor air pollution. The deployment of a large number of sensors across a small geographic area would have potential benefits to supplement traditional monitoring networks with additional geographic and temporal measurement resolution, if the data quality were sufficient. To understand the capability of emerging air sensor technology, the Community Air Sensor Network (CAIRSENSE) project deployed low-cost, continuous, and commercially available air pollution sensors at a regulatory air monitoring site and as a local sensor network over a surrounding ˜ 2 km area in the southeastern United States. Collocation of sensors measuring oxides of nitrogen, ozone, carbon monoxide, sulfur dioxide, and particles revealed highly variable performance, both in terms of comparison to a reference monitor as well as the degree to which multiple identical sensors produced the same signal. Multiple ozone, nitrogen dioxide, and carbon monoxide sensors revealed low to very high correlation with a reference monitor, with Pearson sample correlation coefficient (r) ranging from 0.39 to 0.97, -0.25 to 0.76, and -0.40 to 0.82, respectively. The only sulfur dioxide sensor tested revealed no correlation (r 0.5), step-wise multiple linear regression was performed to determine if ambient temperature, relative humidity (RH), or age of the sensor in number of sampling days could be used in a correction algorithm to improve the agreement. Maximum improvement in agreement with a reference, incorporating all factors, was observed for an NO2 sensor (multiple correlation coefficient R2adj-orig = 0.57, R2adj-final = 0.81); however, other sensors showed no apparent improvement in agreement. A four-node sensor network was successfully able to capture ozone (two nodes) and PM (four nodes) data for an 8-month period of time and show expected diurnal concentration patterns, as well as potential

  12. 36 CFR 1211.525 - Fringe benefits.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Fringe benefits. 1211.525 Section 1211.525 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL... regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  13. 40 CFR 5.525 - Fringe benefits.

    Science.gov (United States)

    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....

  14. 22 CFR 146.525 - Fringe benefits.

    Science.gov (United States)

    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....

  15. 28 CFR 54.525 - Fringe benefits.

    Science.gov (United States)

    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. American Involvement in Fringe Religious Cults

    Science.gov (United States)

    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…

  17. Fringe tracking performance monitoring: FINITO at VLTI

    CERN Document Server

    Merand, A; Berger, J -P; Percheron, I; Poupar, S

    2012-01-01

    Since April 2011, realtime fringe tracking data are recorded simultaneously with data from the VLTI/AMBER interferometric beam combiner. Not only this offers possibilities to post-process AMBER reduced data to obtain more accurate interferometric quantities, it also allows to estimate the performance of the fringe tracking a function of the conditions of seeing, coherence time, flux, etc. First we propose to define fringe tracking performance metrics in the AMBER context, in particular as a function of AMBER's integration time. The main idea is to determine the optimal exposure time for AMBER: short exposures are dominated by readout noise and fringes in long exposures are completely smeared out. Then we present this performance metrics correlated with Paranal local ASM (Ambient Site Monitor) measurements, such as seeing, coherence time or wind speed for example. Finally, we also present some preliminary results of attempts to model and predict fringe tracking performances, using Artificial Neural Networks.

  18. Self-Mixing Fringes of Vertical-Cavity Surface-Emitting Lasers under Dual Reflector Feedback

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang; ZHANG Shu-Lian; ZHANG Lian-Qing; TAN Yi-Dong

    2006-01-01

    The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed.Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensors has been improved by 10 times. The role of the each reflector has been discussed in detail.

  19. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  20. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  1. Preliminary study of a dispersed fringe type sensing system

    Institute of Scientific and Technical Information of China (English)

    Yong Zhang; Gen-Rong Liu; Yue-Fei Wang; Ye-Ping Li; Ya-Jun Zhang; Liang Zhang

    2009-01-01

    Telescopes with large aspherical primary mirrors collect more light and are therefore sought after by astronomers. Instead of using a single large one-piece mirror, smaller segments can be assembled into a useable telescopic primary. Because the seg-ments must fit together to create the effect of a single mirror, segmented optics present unique challenges to the fabrication and testing that are absent in monolithic optics. A dispersed fringe sensor (DFS) using a broadband point source is an efficient method for cophasing and is also highly automated and robust. Unlike the widely adopted Shack-Hartmann Wavefront sensor and curvature wavefront sensor with edge sensors for cali-bration of relative pistons, DFS can estimate the piston between segments by only using the spectrum formed by the transmissive grating's dispersion, and therefore can replace the edge sensors, which are difficult to calibrate. We introduce the theory of the DFS and Dispersed Hartmann Sensor (DHS) for further utilization of the coarse phasing method of DFS. According to the theory, we bring out the preliminary system design of the cophas-ing experimental system based on DFS and DHS which is now established in our institute. Finally, a summary is reached.

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

    Science.gov (United States)

    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.

  3. Performance of an electrochemical COD (chemical oxygen demand) sensor with an electrode-surface grinding unit.

    Science.gov (United States)

    Geun Jeong, Bong; Min Yoon, Seok; Ho Choi, Chang; Koang Kwon, Kil; Sik Hyun, Moon; Heui Yi, Dong; Soo Park, Hyung; Kim, Mia; Joo Kim, Hyung

    2007-12-01

    An electrochemical COD (chemical oxygen demand) sensor using an electrode-surface grinding unit was investigated. The electrolyzing (oxidizing) action of copper on an organic species was used as the basis of the COD measuring sensor. Using a simple three-electrode cell and a surface grinding unit, the organic species is activated by the catalytic action of copper and oxidized at a working electrode, poised at a positive potential. When synthetic wastewater was fed into the system, the measured Coulombic yields were found to be dependent on the COD of the synthetic wastewater. A linear correlation between the Coulombic yields and the COD of the synthetic wastewater was established (10-1000 mg L(-1)) when the electrode-surface grinding procedure was activated briefly at 8 h intervals. When various kinds of wastewater samples obtained from various sewage treatment plants were measured, linear correlations (r(2)> or = 0.92) between the measured EOD (electrochemical oxygen demand) value and COD of the samples were observed. At a practical wastewater treatment plant, the measurement system was successfully operated with high accuracy and good stability over 3 months. These experimental results show that the application of the measurement system would be a rapid and practical method for the determination of COD in water industries.

  4. 29 CFR 4.170 - Furnishing fringe benefits or equivalents.

    Science.gov (United States)

    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...

  5. Fringe Benefits: Should We Milk This Sacred Cow?

    OpenAIRE

    Robert W. Turner

    1989-01-01

    Addresses the effect on revenue of taxing fringe benefits. Asks whether taxing fringe benefits would lead to a dramatic decrease in the share of compensation paid in the form of fringes and whether the level of total compensation is affected by the tax free status of fringe benefits.

  6. Cordless hand-held optical 3D sensor

    Science.gov (United States)

    Munkelt, Christoph; Bräuer-Burchardt, Christian; Kühmstedt, Peter; Schmidt, Ingo; Notni, Gunther

    2007-07-01

    A new mobile optical 3D measurement system using phase correlation based fringe projection technique will be presented. The sensor consist of a digital projection unit and two cameras in a stereo arrangement, whereby both are battery powered. The data transfer to a base station will be done via WLAN. This gives the possibility to use the system in complicate, remote measurement situations, which are typical in archaeology and architecture. In the measurement procedure the sensor will be hand-held by the user, illuminating the object with a sequence of less than 10 fringe patterns, within a time below 200 ms. This short sequence duration was achieved by a new approach, which combines the epipolar constraint with robust phase correlation utilizing a pre-calibrated sensor head, containing two cameras and a digital fringe projector. Furthermore, the system can be utilized to acquire the all around shape of objects by using the phasogrammetric approach with virtual land marks introduced by the authors 1, 2. This way no matching procedures or markers are necessary for the registration of multiple views, which makes the system very flexible in accomplishing different measurement tasks. The realized measurement field is approx. 100 mm up to 400 mm in diameter. The mobile character makes the measurement system useful for a wide range of applications in arts, architecture, archaeology and criminology, which will be shown in the paper.

  7. Population redistribution within the rural-urban fringe: a typology of small towns and rural municipalities in the state of New Jersey.

    Science.gov (United States)

    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."

  8. An Efficient Micro Control Unit with a Reconfigurable Filter Design for Wireless Body Sensor Networks (WBSNs

    Directory of Open Access Journals (Sweden)

    Chiung-An Chen

    2012-11-01

    Full Text Available In this paper, a low-cost, low-power and high performance micro control unit (MCU core is proposed for wireless body sensor networks (WBSNs. It consists of an asynchronous interface, a register bank, a reconfigurable filter, a slop-feature forecast, a lossless data encoder, an error correct coding (ECC encoder, a UART interface, a power management (PWM, and a multi-sensor controller. To improve the system performance and expansion abilities, the asynchronous interface is added for handling signal exchanges between different clock domains. To eliminate the noise of various bio-signals, the reconfigurable filter is created to provide the functions of average, binomial and sharpen filters. The slop-feature forecast and the lossless data encoder is proposed to reduce the data of various biomedical signals for transmission. Furthermore, the ECC encoder is added to improve the reliability for the wireless transmission and the UART interface is employed the proposed design to be compatible with wireless devices. For long-term healthcare monitoring application, a power management technique is developed for reducing the power consumption of the WBSN system. In addition, the proposed design can be operated with four different bio-sensors simultaneously. The proposed design was successfully tested with a FPGA verification board. The VLSI architecture of this work contains 7.67-K gate counts and consumes the power of 5.8 mW or 1.9 mW at 100 MHz or 133 MHz processing rate using a TSMC 0.18 μm or 0.13 μm CMOS process. Compared with previous techniques, this design achieves higher performance, more functions, more flexibility and higher compatibility than other micro controller designs.

  9. Development of microcontroller-based acquisition and processing unit for fiber optic vibration sensor

    Science.gov (United States)

    Suryadi; Puranto, P.; Adinanta, H.; Waluyo, T. B.; Priambodo, P. S.

    2017-04-01

    Microcontroller based acquisition and processing unit (MAPU) has been developed to measure vibration signal from fiber optic vibration sensor. The MAPU utilizes a 32-bit ARM microcontroller to perform acquisition and processing of the input signal. The input signal is acquired with 12 bit ADC and processed using FFT method to extract frequency information. Stability of MAPU is characterized by supplying a constant input signal at 500 Hz for 29 hours and shows a stable operation. To characterize the frequency response, input signal is swapped from 20 to 1000 Hz with 20 Hz interval. The characterization result shows that MAPU can detect input signal from 20 to 1000 Hz with minimum signal of 4 mV RMS. The experiment has been set that utilizes the MAPU with singlemode-multimode-singlemode (SMS) fiber optic sensor to detect vibration which is induced by a transducer in a wooden platform. The experimental result indicates that vibration signal from 20 to 600 Hz has been successfully detected. Due to the limitation of the vibration source used in the experiment, vibration signal above 600 Hz is undetected.

  10. Inertial measurement unit-camera calibration based on incomplete inertial sensor information

    Institute of Scientific and Technical Information of China (English)

    Hong LIU; Yu-long ZHOU; Zhao-peng GU

    2014-01-01

    This paper is concerned with the problem of estimating the relative orientation between an inertial measurement unit (IMU) and a camera. Unlike most existing IMU-camera calibrations, the main challenge in this paper is that the information output from the IMU is incomplete. For example, only two tilt information can be read from the gravity sensor of a smart phone. Despite incomplete inertial information, there are strong restrictions between the IMU and camera coordinate systems. This paper addresses the incomplete information based IMU-camera calibration problem by exploiting the intrinsic restrictions among the coordinate transformations. First, the IMU transformation between two poses is formulated with the unknown IMU information. Then the defective IMU information is restored using the complementary visual information. Finally, the Levenberg-Marquardt (LM) algorithm is applied to estimate the optimal calibration result in noisy environments. Experiments on both synthetic and real data show the validity and robustness of our algorithm.

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

    Science.gov (United States)

    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.

  12. PERSPECTIVE: Fire on the fringe

    Science.gov (United States)

    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

  13. Portable air quality sensor unit for participatory monitoring: an end-to-end VESNA-AQ based prototype

    Science.gov (United States)

    Vucnik, Matevz; Robinson, Johanna; Smolnikar, Miha; Kocman, David; Horvat, Milena; Mohorcic, Mihael

    2015-04-01

    Key words: portable air quality sensor, CITI-SENSE, participatory monitoring, VESNA-AQ The emergence of low-cost easy to use portable air quality sensors units is opening new possibilities for individuals to assess their exposure to air pollutants at specific place and time, and share this information through the Internet connection. Such portable sensors units are being used in an ongoing citizen science project called CITI-SENSE, which enables citizens to measure and share the data. The project aims through creating citizens observatories' to empower citizens to contribute to and participate in environmental governance, enabling them to support and influence community and societal priorities as well as associated decision making. An air quality measurement system based on VESNA sensor platform was primarily designed within the project for the use as portable sensor unit in selected pilot cities (Belgrade, Ljubljana and Vienna) for monitoring outdoor exposure to pollutants. However, functionally the same unit with different set of sensors could be used for example as an indoor platform. The version designed for the pilot studies was equipped with the following sensors: NO2, O3, CO, temperature, relative humidity, pressure and accelerometer. The personal sensor unit is battery powered and housed in a plastic box. The VESNA-based air quality (AQ) monitoring system comprises the VESNA-AQ portable sensor unit, a smartphone app and the remote server. Personal sensor unit supports wireless connection to an Android smartphone via built-in Wi-Fi. The smartphone in turn serves also as the communication gateway towards the remote server using any of available data connections. Besides the gateway functionality the role of smartphone is to enrich data coming from the personal sensor unit with the GPS location, timestamps and user defined context. This, together with an accelerometer, enables the user to better estimate ones exposure in relation to physical activities, time

  14. Color fringe projection profilometry using geometric constraints

    Science.gov (United States)

    Cheng, Teng; Du, Qingyu; Jiang, Yaxi

    2017-09-01

    A recently proposed phase unwrapping method using geometric constraints performs well without requiring additional camera, more patterns or global search. The major limitation of this technique is the confined measurement depth range (MDR) within 2π in phase domain. To enlarge the MDR, this paper proposes using color fringes for three-dimensional (3D) shape measurement. Each six fringe periods encoded with six different colors are treated as one group. The local order within one group can be identified with reference to the color distribution. Then the phase wrapped period-by-period is converted into the phase wrapped group-by-group. The geometric constraints of the fringe projection system are used to determine the group order. Such that the MDR is extended from 2π to 12π by six times. Experiment results demonstrate the success of the proposed method to measure two isolated objects with large MDR.

  15. Fringe detection in noisy complex interferograms.

    Science.gov (United States)

    Trouvé, E; Caramma, M; Maître, H

    1996-07-10

    A new algorithm to estimate the two-dimensional local frequencies of phase interferometric data is described. With a complex sine-wave model, demonstration is given that a conventional multiple-signal classification (MUSIC) algorithm can be used in spite of multiplicative noise perturbations. A faster algorithm dedicated to the processing of interferograms is developed and a measure of confidence in the estimate is proposed. We studied numerical performances using synthetic fringes. As a result of the frequency estimation, knowledge of the fringe local width and orientation can be applied to restore noisy phase data. Results of a complex phase filter are presented for real interferograms obtained from synthetic aperture radar images.

  16. Fringe Benefits Compensation of Real Estate Agents and Brokers

    OpenAIRE

    Daniel T. Winkler; W. Keener Hughen

    2012-01-01

    Fringe benefits compensation offered by employers has grown rapidly over the past 50 years. Research in this area has been primarily limited to hourly and salaried employees. This study examines employer-based fringe benefits compensation of real estate agents and brokers. A model is developed that jointly estimates the income, hours worked, and fringe benefits compensation. The findings indicate that fringe benefits increase according to hours worked and the sales professional¡¦s contributio...

  17. Control bandwidth improvements in GRAVITY fringe tracker by switching to a synchronous real time computer architecture

    Science.gov (United States)

    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

  18. The Offerings of Fringe Figures and Migrants

    Science.gov (United States)

    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…

  19. 31 CFR 28.525 - Fringe benefits.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Fringe benefits. 28.525 Section 28.525 Money and Finance: Treasury Office of the Secretary of the Treasury NONDISCRIMINATION ON THE BASIS... medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  20. The Offerings of Fringe Figures and Migrants

    Science.gov (United States)

    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…

  1. 26 CFR 1.132-9 - Qualified transportation fringes.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What...

  2. Mass flow-rate control unit to calibrate hot-wire sensors

    Energy Technology Data Exchange (ETDEWEB)

    Durst, F.; Uensal, B. [FMP Technology GmbH, Erlangen (Germany); Haddad, K. [FMP Technology GmbH, Erlangen (Germany); Friedrich-Alexander-Universitaet Erlangen-Nuernberg, LSTM-Erlangen, Institute of Fluid Mechanics, Erlangen (Germany); Al-Salaymeh, A.; Eid, Shadi [University of Jordan, Mechanical Engineering Department, Faculty of Engineering and Technology, Amman (Jordan)

    2008-02-15

    Hot-wire anemometry is a measuring technique that is widely employed in fluid mechanics research to study the velocity fields of gas flows. It is general practice to calibrate hot-wire sensors against velocity. Calibrations are usually carried out under atmospheric pressure conditions and these suggest that the wire is sensitive to the instantaneous local volume flow rate. It is pointed out, however, that hot wires are sensitive to the instantaneous local mass flow rate and, of course, also to the gas heat conductivity. To calibrate hot wires with respect to mass flow rates per unit area, i.e., with respect to ({rho}U), requires special calibration test rigs. Such a device is described and its application is summarized within the ({rho}U) range 0.1-25 kg/m{sup 2} s. Calibrations are shown to yield the same hot-wire response curves for density variations in the range 1-7 kg/m{sup 3}. The application of the calibrated wires to measure pulsating mass flows is demonstrated, and suggestions are made for carrying out extensive calibrations to yield the ({rho}U) wire response as a basis for advanced fluid mechanics research on ({rho}U) data in density-varying flows. (orig.)

  3. Modelling and analysis of fringing and metal thickness effects in MEMS parallel plate capacitors

    Science.gov (United States)

    Shah, Kriyang; Singh, Jugdutt; Zayegh, Aladin

    2005-12-01

    This paper presents a detailed design and analysis of fringing and metal thickness effects in a Micro Electro Mechanical System (MEMS) parallel plate capacitor. MEMS capacitor is one of the widely deployed components into various applications such are pressure sensor, accelerometers, Voltage Controlled Oscillator's (VCO's) and other tuning circuits. The advantages of MEMS capacitor are miniaturisation, integration with optics, low power consumption and high quality factor for RF circuits. Parallel plate capacitor models found in literature are discussed and the best suitable model for MEMS capacitors is presented. From the equations presented it is found that fringing filed and metal thickness have logarithmic effects on capacitance and depend on width of parallel plates, distance between them and thickness of metal plates. From this analysis a precise model of a MEMS parallel plate capacitor is developed which incorporates the effects of fringing fields and metal thickness. A parallel plate MEMS capacitor has been implemented using Coventor design suite. Finite Element Method (FEM) analysis in Coventorware design suite has been performed to verify the accuracy of the proposed model for suitable range of dimensions for MEMS capacitor Simulations and analysis show that the error between the designed and the simulated values of MEMS capacitor is significantly reduced. Application of the modified model for computing capacitance of a combed device shows that the designed values greatly differ from simulated results noticeably from 1.0339pF to 1.3171pF in case of fringed devices.

  4. Combined use of a priori data for fast system self-calibration of a non-rigid multi-camera fringe projection system

    Science.gov (United States)

    Stavroulakis, Petros I.; Chen, Shuxiao; Sims-Waterhouse, Danny; Piano, Samanta; Southon, Nicholas; Bointon, Patrick; Leach, Richard

    2017-06-01

    In non-rigid fringe projection 3D measurement systems, where either the camera or projector setup can change significantly between measurements or the object needs to be tracked, self-calibration has to be carried out frequently to keep the measurements accurate1. In fringe projection systems, it is common to use methods developed initially for photogrammetry for the calibration of the camera(s) in the system in terms of extrinsic and intrinsic parameters. To calibrate the projector(s) an extra correspondence between a pre-calibrated camera and an image created by the projector is performed. These recalibration steps are usually time consuming and involve the measurement of calibrated patterns on planes, before the actual object can continue to be measured after a motion of a camera or projector has been introduced in the setup and hence do not facilitate fast 3D measurement of objects when frequent experimental setup changes are necessary. By employing and combining a priori information via inverse rendering, on-board sensors, deep learning and leveraging a graphics processor unit (GPU), we assess a fine camera pose estimation method which is based on optimising the rendering of a model of a scene and the object to match the view from the camera. We find that the success of this calibration pipeline can be greatly improved by using adequate a priori information from the aforementioned sources.

  5. Research on a Power Management System for Thermoelectric Generators to Drive Wireless Sensors on a Spindle Unit

    Directory of Open Access Journals (Sweden)

    Sheng Li

    2014-07-01

    Full Text Available Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle.

  6. Research on a power management system for thermoelectric generators to drive wireless sensors on a spindle unit.

    Science.gov (United States)

    Li, Sheng; Yao, Xinhua; Fu, Jianzhong

    2014-07-16

    Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle.

  7. Fringe positions in double-exposure speckle photography.

    Science.gov (United States)

    Hinsch, K

    1989-12-15

    Double-exposure records in speckle photography or particle image velocimetry are often evaluated by analysis of the system of Young's diffraction fringes. Fringe spacing, necessary to calculate the displacement, is determined from the positions of fringe maxima or minima. These, however, are influenced by the diffraction halo function and by fringe visibility. A generalized theory of the effects is presented, including position dependent visibility and fringe phase. Evaluations are given for disk-shaped particle images in particle image velocimetry, and for coherent and incoherent speckle photography. Fringe shifts are determined numerically for commonly encountered values of fringe density and visibility thus presenting a basis for rapid assessment of accuracy in metrological experiments.

  8. Airborne observations of bioaerosol over the Southeast United States using a Wideband Integrated Bioaerosol Sensor

    Science.gov (United States)

    Ziemba, Luke D.; Beyersdorf, Andreas J.; Chen, Gao; Corr, Chelsea A.; Crumeyrolle, Suzanne N.; Diskin, Glenn; Hudgins, Charlie; Martin, Robert; Mikoviny, Tomas; Moore, Richard; Shook, Michael; Thornhill, K. Lee; Winstead, Edward L.; Wisthaler, Armin; Anderson, Bruce E.

    2016-07-01

    Biological aerosols represent a diverse subset of particulate matter that is emitted directly to the atmosphere in the form of (but not limited to) bacteria, fungal spores, pollens, viruses, and plant debris. These particles can have local air quality implications, but potentially play a larger climate role by acting as efficient ice nucleating particles (INPs) and cloud condensation nuclei. We have deployed a Wideband Integrated Bioaerosol Sensor on the NASA DC-8 aircraft to (1) quantify boundary layer (BL) variability of fluorescent biological aerosol particle (FBAP) concentrations in the Southeast United States (SEUS), (2) link this variability explicitly to land cover heterogeneity in the region, and (3) examine the vertical profile of bioaerosols in the context of convective vertical redistribution. Flight-averaged FBAP concentrations ranged between 0.1 and 0.43 scm-3 (cm-3 at standard temperature and pressure) with relatively homogeneous concentrations throughout the region; croplands showed the highest concentrations in the BL (0.37 scm-3), and lowest concentrations were associated with evergreen forests (0.24 scm-3). Observed FBAP concentrations are in generally good agreement with model parameterized emission rates for bacteria, and discrepancies are likely the result of fungal spore contributions. Shallow convection in the region is shown to be a relatively efficient lofting mechanism as the vertical transport efficiency of FBAP is at least equal to black carbon aerosol, suggesting that ground-level FBAP survives transport into the free troposphere to be available for INP activation. Comparison of the fraction of coarse-mode particles that were biological (fFBAP) suggested that the SEUS (fFBAP = 8.5%) was a much stronger source of bioaerosols than long-range transport during a Saharan Air Layer (SAL) dust event (fFBAP = 0.17%) or summertime marine emissions in the Gulf of Mexico (fFBAP = 0.73%).

  9. Comparison of LASER and LED illumination for fiber optic fringe projection

    Science.gov (United States)

    Matthias, Steffen; Kästner, Markus; Reithmeier, Eduard

    2016-04-01

    The inspection of functional elements is a crucial part of modern production cycles. However, with higher integration of production machinery and products, the accessibility for measurement systems is more and more limited. A solution for this problem can be found in endoscopy techniques, which are able to transport the image information for optical measurement methods. In this paper, an optical inspection system based on the fringe projection profilometry technique is presented. The fiber-optic fringe projection system uses two high-resolution image fibers to connect a compact sensor head to the pattern generation and camera unit. In order to keep inspection times low, the system is developed with particular focus on fast projection times. This can be achieved by using a digital micro-mirror device, which is capable of projecting grey-scale patterns at a rate of more than 10 images per second. However, due to the low numerical aperture of the optical fibers, a limiting factor for the pattern rate is the illumination path of the pattern generator. Two different designs of the illumination path are presented, which are based on a LASER light source as well as a LED light source. Due to low beam divergence and high intensities LASERs are well suited for fiber coupling. Unfortunately, the coherent property of the light has negative effects in certain measurement applications, as interference patterns, the so called speckle, appear on rough surfaces. Although speckle reducing methods are employed in the LASER beam path, the emergence of interference cannot be prevented completely. As an alternative, an illumination path based on a LED light source is demonstrated. To compare the effects of the speckle, based on measurements on a planar calibration standard both designs are compared in terms of phase noise, which is directly related to the noise in the reconstructed 3-D point data. Additionally, optical power measurements of both methods are compared to give an

  10. Saturn's F-ring and inner satellite

    Science.gov (United States)

    1981-01-01

    Saturn's F-ring and its inner shepherding satellite (1980S27) are pictured in this closeup Voyager 2 image acquired Aug. 25 from a range of 365,000 kilometers (227,000 miles). Features as small as 6 km. (3.7 mi.) across are visible. The satellite is elongated and irregular, with its longest axis pointing toward the center of Saturn (toward the upper right in this view). As seen here, the F-ring is thin and does not show the multiple, braided structure Voyager 1 saw last fall. Nor is there any indication of a band or kink in the ring at its closest point to the shepherd; such a feature would be consistent with some of the theories advanced on the formation of the braids. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  11. Flexible calibration procedure for fringe projection profilometry

    OpenAIRE

    Vargas, Javier; Quiroga Mellado, Juan Antonio; Terrón López, María José

    2007-01-01

    A novel calibration method for whole field three-dimensional shape measurement by means of fringe projection is presented. Standard calibration techniques, polynomial-and model-based, have practical limitations such as the difficulty of measuring large fields of view, the need to use precise z stages, and bad calibration results due to inaccurate calibration points. The proposed calibration procedure is a mixture of the two main standard techniques, sharing their benefits and avoiding their m...

  12. New ITF measure method based on fringes

    Science.gov (United States)

    Fang, Qiaoran; Liu, Shijie; Gao, Wanrong; Zhou, You; Liu, HuanHuan

    2016-01-01

    With the unprecedented developments of the intense laser and aerospace projects', the interferometer is widely used in detecting middle frequency indicators of the optical elements, which put forward very high request towards the interferometer system transfer function (ITF). Conventionally, the ITF is measured by comparing the power spectra of known phase objects such as high-quality phase step. However, the fabrication of phase step is complex and high-cost, especially in the measurement of large-aperture interferometer. In this paper, a new fringe method is proposed to measure the ITF without additional objects. The frequency was changed by adjusting the number of fringes, and the normalized transfer function value was measured at different frequencies. The ITF value measured by fringe method was consistent with the traditional phase step method, which confirms the feasibility of proposed method. Moreover, the measurement error caused by defocus was analyzed. The proposed method does not require the preparation of a step artifact, which greatly reduces the test cost, and is of great significance to the ITF measurement of large aperture interferometer.

  13. Spectral interference fringes in chirped large-mode-area fiber Bragg gratings

    Science.gov (United States)

    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.

  14. Design of an Integrated Sensor Platform for Vital Sign Monitoring of Newborn Infants at Neonatal Intensive Care Units

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2010-01-01

    Full Text Available Continuous health status monitoring and advances in medical treatments have resulted in a significant increase of survival rate in critically ill infants admitted into Neonatal Intensive Care Units (NICUs. The quality of life and long-term health prospects of the neonates depend increasingly on the reliability and comfort of the monitoring systems. In this paper, we present the design work of a smart jacket for vital sign monitoring of neonates at a NICU. The design represents a unique integration of sensor technology, user focus and design aspects. Textile sensors, a reflectance pulse oximeter and a wearable temperature sensor were proposed to be embedded into the smart jacket. Location of the sensor, materials and appearance were designed to optimize the functionality, patient comfort and the possibilities for aesthetic features. Prototypes were built for demonstrating the design concept and experimental results were obtained from tests on premature babies at the NICU of M�xima Medical Centre (MMC in Veldhoven, the Netherlands.

  15. Regularized quadratic cost function for oriented fringe-pattern filtering.

    Science.gov (United States)

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

    2009-06-01

    We use the regularization theory in a Bayesian framework to derive a quadratic cost function for denoising fringe patterns. As prior constraints for the regularization problem, we propose a Markov random field model that includes information about the fringe orientation. In our cost function the regularization term imposes constraints to the solution (i.e., the filtered image) to be smooth only along the fringe's tangent direction. In this way as the fringe information and noise are conveniently separated in the frequency space, our technique avoids blurring the fringes. The attractiveness of the proposed filtering method is that the minimization of the cost function can be easily implemented using iterative methods. To show the performance of the proposed technique we present some results obtained by processing simulated and real fringe patterns.

  16. A Method To Remove Fringes From Images Using Wavelets

    CERN Document Server

    Rojo, P; Rojo, Patricio; Harrington, Joseph

    2006-01-01

    We have developed a new method that uses wavelet analysis to remove interference fringe patterns from images. This method is particularly useful for flat fields in the common case where fringes vary between the calibration and object data. We analyze the efficacy of this method by creating fake flats with fictitious fringes and removing the fringes. We find that the method removes 90% of the fringe pattern if its amplitude is equal to the random noise level and 60% if the fringe amplitude is $\\approx 1/10$ of the noise level. We also present examples using real flat field frames. A routine written in the Interactive Data Language (IDL) that implements this algorithm is available from the authors and as an attachment to this paper.

  17. Colloid Mobilization and Transport during Capillary Fringe Fluctuations

    Science.gov (United States)

    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.

  18. LineVISAR. A fringe-trace data analysis program

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, Michael D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    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.

  19. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications

    Directory of Open Access Journals (Sweden)

    Mohammad Tariqul Islam

    2015-05-01

    Full Text Available This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator and CLS (capacitive loaded strip unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2 covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors.

  20. Automatic abstraction of interference fringes with image technique

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An automatic abstraction technique of interference fringes used in phase-modulation and phase-scanning-modulation interferometer is presented.For the measurement of amplitudes of interference fringes,fringes are fitted and their central points are determined automatically according to their distribution rules.However,for the measurement of their phases,fringes should be recognized and processed with different calculating algorithms and least-square optimization methods depending on the scanning modulation mode.When this technique is used for measurement of surface roughness,the measurement uncertainty is better than 5nm and the repeatability is less than 5%.

  1. Analytical transfer matrix of a quadrupole fringe

    Institute of Scientific and Technical Information of China (English)

    PENG Yue-Mei; XU Gang

    2011-01-01

    The analytical linear transfer matrices for different quadrupole fringes including quadratic,high order power and exponential models are deduced in this paper.As an example,the transfer matrices of the quadrupole BEPC Ⅱ 105Q are computed for the above three models and compared with hard edge and sliceby-slice models in cases of near 60° and 90° FODO cells.These models' results are much better than the hard edge model's,and can meet the requirement of accurate calculation.

  2. Fringe Projection Measurement System in Reverse Engineering

    Institute of Scientific and Technical Information of China (English)

    林朝辉; 何海涛; 郭红卫; 陈明仪; 石璇; 俞涛

    2005-01-01

    Acquisition of physical data with high precision is a key step in reverse engineering ( RE). It is an important stimulative for the progress of reverse engineering with which various digitizing devices are invented, developed and made applicable. This paper introduces a three dimensional optical measurement method based on digital fringe projection technique in RE to improve the technique through its application. A practical example is presented and the result demonstrates the applicability and feasibility of the measurement system as well as the reliability and validity of relevant methods and algorithms.

  3. STRATEGI YANG TEPAT UNTUK MENGANTISIPASI PERKEMBANGAN FRINGE-SETTLEMENTS DI KA-WASAN RURAL-URBAN FRINGE BERDASARKAN MODEL KOMBINASI

    Directory of Open Access Journals (Sweden)

    Imma Widyawati Agustin

    2012-11-01

    Full Text Available This research is used a combination model by the proportion of urban land use functions, residential properties and the proportion of agricultural land use. It was also calculated based on the distance bands. The objective of this research is to improve the policy of fringe-settlements development in the rural-urban fringe area. This result are: (1 There has been a conversion of productive agricultural-land into residential-land. (2 New fringe-settlements should be established in inner fringe. Outer fringe area should be keep for agricultural-land. Thus, there is a balance in the rural-urban fringe area. (3 An appropriate strategy for rural-urban fringe area is: Tax Defferal and Abatement Laws is suitable to be applied in the inner fringe area because the majority of the population in no longer committed to preserve agricultural and activities. Utility Extension Policy and Police Power Mechanism are suitable to be applied in the outer fringe area because the availability of agricultural land is still a lot and the farmer committed to agricultural land and agricultural activities.

  4. Fast Thermal Calibration of Low-Grade Inertial Sensors and Inertial Measurement Units

    Directory of Open Access Journals (Sweden)

    Yalong Ban

    2013-09-01

    Full Text Available The errors of low-cost inertial sensors, especially Micro-Electro Mechanical Systems (MEMS ones, are highly dependent on environmental conditions such as the temperature. Thus, there is a need for the development of accurate and reliable thermal compensation models to reduce the impact of such thermal drift of the sensors. Since the conventional thermal calibration methods are typically time-consuming and costly, an efficient thermal calibration method to investigate the thermal drift of a full set of gyroscope and accelerometer errors (i.e., biases, scale factor errors and non-orthogonalities over the entire temperature range in a few hours is proposed. The proposed method uses the idea of the Ramp method, which removes the time-consuming process of stabilizing the sensor temperature, and addresses its inherent problems with several improvements. We change the temperature linearly for a complete cycle and take a balanced strategy by making comprehensive use of the sensor measurements during both heating and cooling processes. Besides, an efficient 8-step rotate-and-static scheme is designed to further improve the calibration accuracy and efficiency. Real calibration tests showed that the proposed method is suitable for low-grade IMUs and for both lab and factory calibration due to its efficiency and sufficient accuracy.

  5. Fast thermal calibration of low-grade inertial sensors and inertial measurement units.

    Science.gov (United States)

    Niu, Xiaoji; Li, You; Zhang, Hongping; Wang, Qingjiang; Ban, Yalong

    2013-09-12

    The errors of low-cost inertial sensors, especially Micro-Electro Mechanical Systems (MEMS) ones, are highly dependent on environmental conditions such as the temperature. Thus, there is a need for the development of accurate and reliable thermal compensation models to reduce the impact of such thermal drift of the sensors. Since the conventional thermal calibration methods are typically time-consuming and costly, an efficient thermal calibration method to investigate the thermal drift of a full set of gyroscope and accelerometer errors (i.e., biases, scale factor errors and non-orthogonalities) over the entire temperature range in a few hours is proposed. The proposed method uses the idea of the Ramp method, which removes the time-consuming process of stabilizing the sensor temperature, and addresses its inherent problems with several improvements. We change the temperature linearly for a complete cycle and take a balanced strategy by making comprehensive use of the sensor measurements during both heating and cooling processes. Besides, an efficient 8-step rotate-and-static scheme is designed to further improve the calibration accuracy and efficiency. Real calibration tests showed that the proposed method is suitable for low-grade IMUs and for both lab and factory calibration due to its efficiency and sufficient accuracy.

  6. sensor for mainstream capnography based on TDLAS

    Science.gov (United States)

    Hartmann, A.; Strzoda, R.; Schrobenhauser, R.; Weigel, R.

    2014-09-01

    The setup and signal processing for a mainstream capnography sensor is presented in this paper. The probe exhibits an optical path length of 2.5 cm and is equipped with a vertical-cavity surface-emitting laser at 2 μm. The sensor does not need any calibration, since the CO2 absorption line as well as the laser background is measured using direct tunable diode laser absorption spectroscopy. Unavoidable optical fringes are reduced with a self-developed fringe rejection method. The sensor achieves a concentration resolution 30 Hz.

  7. Sensor fusion system to estimate the trajectory of a low cost mobile robotic platform using an Inertial Measurement Unit

    Science.gov (United States)

    Botero V., J.-S.; M. Rico, G.; Villegas C, J.-P.

    2016-07-01

    In this paper, the development and implementation of an algorithm is presented to identify the trajectory of a mobile robot based on data from an Inertial Measurement Unit with nine degrees of freedom consisting of a 3-axis accelerometers, an 3-axis gyroscopes, an 3- axis magnetometers, and an additional temperature sensor to compensate for temperature errors. The combined information from this set of sensors allows determining the trajectory and orientation of the robot at any moment to complement the information from its navigation system. Initially, it was necessary to build controlled test environments that allow observing and getting to know the trajectory and the dimensions thereof for capturing the raw data of the mobile robotic platform. Then, the data obtained form the sensor was processed off-line applying a Kalman filter with the aim to remove Gaussian noise; to estimating the trajectory and the absolute orientation of the mobile robotic platform the proposed algorithm was implemented. This implementation used the hardware elements are inexpensive, thus allowing the necessary testing, the data analysis and the interpretation of the outcome to be replicable and to be used as an educational tool within courses of undergraduate and master level. The elements of hardware used in this implementation are cheap, allowing its reproduction for the analysis and interpretation of data and can be used as an educational tool in courses of undergraduate and master level.

  8. 29 CFR 4.52 - Fringe benefit determinations.

    Science.gov (United States)

    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...

  9. 26 CFR 1.132-6 - De minimis fringes.

    Science.gov (United States)

    2010-04-01

    ... tickets; coffee, doughnuts, and soft drinks; local telephone calls; and flowers, fruit, books, or similar... 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...

  10. Increase in sensitivity of sensor units of environment refraction index change based on superficial plasmon resonance

    Directory of Open Access Journals (Sweden)

    Ushenin Yu. V.

    2011-04-01

    Full Text Available Results of computer modeling of an angular spectrum superficial plasmon resonance in metal films measurements with device PLAZMON-5 with infra-red radiator are analysed. It is shown that use of an infra-red source of radiation allows to improve sensitivity of sensor device in comparison with source of visible light. On an example of dielectric refraction indexes measurement with PLAZMON-5 device experimental check of theoretical calculations has been carried out.

  11. Imaging of mass transfer process using artificial fringe deflection

    Science.gov (United States)

    Chhaniwal, Vani K.; Narayanamurthy, Chittur S.; Anand, Arun

    2014-07-01

    A noninterferometric technique used to measure the diffusion coefficients of transparent liquid solutions is reported. This technique uses a white light source and a diffusion cell, with an artificially developed fringe pattern of dark and white stripes at its entrance. As the diffusion process takes place in the cell, the light passing through this nonuniform refractive index medium will bend toward the higher refractive index region, which results in a fringe shift. This shift in the fringe pattern at different times is recorded in a personal computer (PC) using a CCD camera for the calculation of diffusion coefficients. The fringe shift is calculated after skeletonization and linear fit of the captured fringe system. The diffusion coefficient of different concentrations of ammonium dihydrogen phosphate was determined using the proposed technique and the measured values lay within 1% of the reported values. Detailed theoretical and experimental analyses with a comparison of other existing results are discussed.

  12. Experimental evidence for formation mechanism of regular circular fringes

    Science.gov (United States)

    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.

  13. Micro analysis of fringe field formed inside LDA measuring volume

    Science.gov (United States)

    Ghosh, Abhijit; Nirala, A. K.

    2016-05-01

    In the present study we propose a technique for micro analysis of fringe field formed inside laser Doppler anemometry (LDA) measuring volume. Detailed knowledge of the fringe field obtained by this technique allows beam quality, alignment and fringe uniformity to be evaluated with greater precision and may be helpful for selection of an appropriate optical element for LDA system operation. A complete characterization of fringes formed at the measurement volume using conventional, as well as holographic optical elements, is presented. Results indicate the qualitative, as well as quantitative, improvement of fringes formed at the measurement volume by holographic optical elements. Hence, use of holographic optical elements in LDA systems may be advantageous for improving accuracy in the measurement.

  14. Adaptive DFT-based Interferometer Fringe Tracking

    Science.gov (United States)

    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.

  15. Advancing Discrimination Performance by Integrating an Inertial Measurement Unit with a Handheld EMI Sensor

    Science.gov (United States)

    2012-07-01

    sensor head (bottom left) and the measured EMI data (bottom right). Spatial Trajectory EM I D ata and M odel Fit Sweep Pattern -1.0 -0.5 0.0 X (m) 0.6...using the grid template are stored electronically as collected on the Allegro data acquisition computer and downloaded via serial port to a notebook...output options ( serial lines, USB ports, etc.). A serial line is used to provide synchronization of the IMU data with the EM61 data. The serial line

  16. Design, Fabrication and pseudo Field Evaluation of a Sugar Beet Crust Breaker and Weeding Unit Equipped with an Infrared Sensor

    Directory of Open Access Journals (Sweden)

    E Chaligar

    2014-09-01

    Full Text Available In conventional cultivation of sugar beet the weeding and crust breaking are mostly performed manually. The objectives of this research were to design, fabricate and evaluate a soil crust breaker and weeding implement equipped with a detecting sensor. Each unit consisted of a distance detecting sensor and a hydro-motor for driving the blades and pneumatic valves for moving the blades. The hydro-motor was activated by the sensors. To avoid damaging the plants, a command signal was sent to the pneumatic valves to move the blades up and down and pass safely. Three configurations of cutting blades were considered which could be mounted to the crust breaker. The field evaluation was conducted with two tractor forward speeds (0.4 and 1 km h-1 and four plant-to-plant spacings within rows (20, 25, 30 and 40 cm all with three different blade shapes. For field evaluation split plot experiments arranged in a completely randomized block design with three replications. The number of plants damaged (evaluated only for four-lobe blades and size of broken crusts (evaluated for all blade shapes for various treatments were recorded and compared. The results of analysis indicated that the higher the inter-row spacing the lower the injury to the plant. The highest and the least damage to the plants occurred for within-row plant spacings of 20 and 40 cm, respectively. The forward speed was also significantly affected the percent of plant damaged. The forward speed of 1 km h-1 at 20 cm spacing had the most (59% and the speed of 0.40 km h-1 at 40 cm spacing had the least effect (3.3% on the percent of plant damage. The two-lobe blade could result in the maximum surface area broken.

  17. Studi Awal Teknologi WIFI Untuk Diimplementasikan Pada Pembuatan Prototipe Sistem Remote Terminal Unit Multi Sensor Dengan Energi Mandiri

    Directory of Open Access Journals (Sweden)

    Asep Insani

    2012-09-01

    Full Text Available Dalam makalah ini dipaparkan tentang hasil studi awal teknologi wifi dalam rangka perancangan dan pembuatan prototipe sistem remote terminal unit (RTU multi sensor dengan energi mandiri untuk mercusuar di wilayah pulau-pulau kecil dan perbatasan yang akan digunakan untuk pengukuran dan komunikasi data serta pemantauan lingkungan. Dalam rangka pembuatan prototipe tersebut terlebih dahulu dibuat model sistem skala laboratorium, kemudian disempurnakan dan dikembangkan menjadi prototipe sistem. Seiring dengan pembuatan model skala laboratorium telah dilakukan pecobaan-percobaan meliputi mode operasi wireless, analisa dan pengamatan karakteristik teknologi wifi, mengetahui jarak optimal jaringan kabel di beberapa tempat dan jarak yang berbeda dengan menggunakan laptop. Dari penelitian ini didapat hasil percobaan yang terkait dengan posisi dan jarak yang optimal untuk mengakses jaringan nirkabel yang digunakan sebagai masukan atau bahan pertimbangan untuk penempatan suatu akses point dari RTU.  Dengan demikian  pengguna jaringan nirkabel dapat dengan mudah mendapatkan signal dan transfer rate yang paling optimum disetiap lokasi disekitar mercusuar.

  18. STRATEGI YANG TEPAT UNTUK MENGANTISIPASI PERKEMBANGAN FRINGE-SETTLEMENTS DI KA-WASAN RURAL-URBAN FRINGE BERDASARKAN MODEL KOMBINASI

    OpenAIRE

    Imma Widyawati Agustin; Hisashi Kubota

    2012-01-01

    This research is used a combination model by the proportion of urban land use functions, residential properties and the proportion of agricultural land use. It was also calculated based on the distance bands. The objective of this research is to improve the policy of fringe-settlements development in the rural-urban fringe area. This result are: (1) There has been a conversion of productive agricultural-land into residential-land. (2) New fringe-settlements should be established in inner frin...

  19. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Taxation of fringe benefits-1985 through 1988..., and Taxable Income § 1.61-2T Taxation of fringe benefits—1985 through 1988 (temporary). (a) Fringe.... This section is effective from January 1, 1985, to December 31, 1988, with respect to fringe...

  20. 29 CFR 4.173 - Meeting requirements for vacation fringe benefits.

    Science.gov (United States)

    2010-07-01

    ... fringe benefit determinations issued under the Act require an employer to furnish to employees working on... applicable fringe benefit determination, an employer must take the following two factors into consideration... benefits under fringe benefit determinations issued pursuant to the Act. (4) Some fringe...

  1. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Science.gov (United States)

    2010-07-01

    ... fringe benefit determination by furnishing any equivalent combinations of “bona fide” fringe benefits or... benefit determination contained in the contract for fringe benefits which are so specified, the... obligation by furnishing, in lieu of those benefits specified in the applicable fringe benefit...

  2. Fringe inverse videogrammetry based on global pose estimation.

    Science.gov (United States)

    Xiao, Yong-Liang; Su, Xianyu; Chen, Wenjing

    2011-10-10

    Fringe inverse videogrammetry based on global pose estimation is presented to measure a three-dimensional (3D) coordinate. The main components involve an LCD screen, a tactile probe equipped with a microcamera, and a portable personal computer. The LCD is utilized to display fringes, a microcamera is installed on the tactile probe, and the 3D coordinate of the center of the probe tip can be calculated through the microcamera's pose. Fourier fringe analysis is exploited to complete subpixel location of reference points. A convex-relaxation optimization algorithm is employed to estimate the global camera pose, which guarantees global convergence compared with bundle adjustment, a local pose estimation algorithm. The experiments demonstrate that fringe inverse videogrammetry can measure the 3D coordinate precisely. © 2011 Optical Society of America

  3. Does Gender Influence the Provision of Fringe Benefits?

    DEFF Research Database (Denmark)

    Rand, John; Tarp, Finn

    2011-01-01

    leave, social benefits, and health insurance. This gender effect exists especially with regard to mandatory social insurance and is robust to the inclusion of standard determinants of wage compensation. The study also explores whether this finding is linked to gender differences in social networks......This contribution studies the provision of fringe benefits using a unique survey of small and medium-sized enterprises (SMEs) in Vietnam. Analysis of the survey reveals that women who own SMEs are more likely than men who own similar firms to provide employees with fringe benefits such as annual...... and workforce structure, worker recruitment mechanisms, and the degree of unionization. However, these factors cannot fully account for the observed differences in fringe benefits along the “gender of owner” dimension. There remains a sizable and unexplained fringe benefits premium paid to employees in women...

  4. Ghost fringe removal techniques using Lissajous data presentation

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. Design of the wavefront sensor unit of ARGOS, the LBT laser guide star system

    CERN Document Server

    Bonaglia, Marco

    2012-01-01

    ARGOS is the laser guide star ground layer adaptive optics system of the LBT. ARGOS is designed to bring a moderate but uniform reduction of the PSF size over a FoV as large as 4x4arcmin, allowing a significative increase of the science throughput of LUCI, the LBT NIR imager and MOS. ARGOS relays on 3 Rayleigh beacons to sense the lower layers of the atmosphere achieving almost 100% sky coverage. The ground layer AO correction is allowed by the 2 adaptive secondaries of the LBT. This PhD thesis first discusses a study based on numerical simulations and aimed to evaluate the performance of ARGOS. This work has been carried out using CAOS and representing in the code most of the features that characterize the system itself: as the laser beacon propagation in the atmosphere, the SH type wavefront sensing, the AO reconstruction and closed loop delays and the atmosphere tip-tilt sensing done using a NGS and a quad-cell type sensor. The results obtained in this study are in agreement and definitively confirm the pe...

  7. Community Air Sensor Network (CAIRSENSE) project: Evaluation of low-cost sensor performance in a suburban environment in the southeastern United States

    Science.gov (United States)

    Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of a large number of sensors across a small geographic area would have potential benefits to supplement traditional monitoring n...

  8. Intuitive decisions on the fringes of consciousness

    Directory of Open Access Journals (Sweden)

    Mark C. Price

    2008-01-01

    Full Text Available Decision making research often dichotomises between more deliberative, cognitive processes and more heuristic, intuitive and emotional processes. We argue that within this two-systems framework (e.g., Kahneman, 2002 there is ambiguity over how to map the System 1/System 2 axis, and the notion of intuitive processing, onto the distinction between conscious and non-conscious processes. However the convergent concepts of experience-based metacognitive judgements (Koriat, 2007 and of fringe consciousness (Mangan, 1993 can clarify intuitive processing as an informative extit{conscious feeling} without conscious access to the antecedents of the feeling. We stress that these intuitive feelings can be used to guide behaviour in a controlled and contextually sensitive manner that would not be permitted by purely non-conscious influences on behaviour. An outline is provided for how to empirically recognise these intuitive feelings. This is illustrated with an example from research on implicit learning where intuitive feelings may play an important role in peoples' decisions and judgements. Finally we suggest that our approach to understanding intuitive feelings softens rather than reinforces the two-systems dichotomy.

  9. Fluorogenic mercury ion sensor based on pyrene-amino mercapto thiadiazole unit.

    Science.gov (United States)

    Rani, B Kirthika; John, S Abraham

    2017-09-15

    A highly selective and sensitive determination of Hg(2+) in water samples with bioimaging applications in living cells using a fluorogenic pyrene-amino mercapto thiadiazole (PYAMT) probe is described. The probe PYAMT exhibited three absorption peaks at 333, 348 and 394nm and emission maxima at 378, 388 and 397nm (λex=348nm). It showed significant fluorescent quenching (96%) with I/I0=0.051 upon the addition of 2.5μM Hg(2+) ion in CH3CN(ACN):H2O (1:1, v/v; pH 7.2), whereas its fluorescence remained unaltered in the presence of other metal ions. The quenching phenomenon is attributed to the heavy atom effect of Hg(2+) ion followed by electron transfer. The fluorescence intensity decreased linearly against a wide range from 100nM to 2.5μM Hg(2+) (R(2)=0.9937) with a limit of detection as low as 0.35nM (S/N=3). The binding stoichiometry ratio of PYAMT-Hg(2+) is proved to be 1:1 by fluorescence and DFT measurements. The sensor possesses high association constant with Hg(2+) ion in the order of 9.08×10(5)M(-1) and it is also capable of reversibly detecting cysteine with OFF-ON mechanism. Finally, the proposed method is successfully applied to selectively detect Hg(2+) ion in real water samples and bioimaging studies in live cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Removing the Fringes from Space Telescope Imaging Spectrograph Slitless Spectra

    Science.gov (United States)

    Malumuth, Eliot M.; Hill, Robert S.; Gull, Ted; Woodgate, Bruce E.; Bowers, Charles W.; Kimble, Randy A.; Lindler, Don; Plait, Phil; Blouke, Morley

    2003-02-01

    Using what is known about the physical and chemical structure of the CCD detector on the Space Telescope Imaging Spectrograph (STIS) and over 50 calibration images taken with different wavelength mappings onto the detector, we have devised a model function that allows us to predict the fringing of any spectral image taken with the STIS CCD. This function is especially useful for spectra taken without a slit with the G750L grating. The STIS parallel observing program uses this ``slitless spectroscopy'' mode extensively. The arbitrary mapping of wavelength versus position that results from each source's chance position in the field renders direct calibration of the fringe amplitudes in this mode impossible. However, we find that correcting observed data using our semiempirical fringing model produces a substantial reduction in the fringe amplitudes. Tests using the flux calibration white dwarf standard G191-B2B show that we can reduce the fringe amplitude in the 9000-10000 Å region from about 20% peak to peak (10% rms) to about 4% peak to peak (2% rms) using the model, while a standard calibration using a ``fringe flat'' reduces the fringe amplitudes to 3.3% peak to peak (1.7% rms). The same technique is applicable to other astronomical CCDs. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Funding of this activity was through the Space Telescope Imaging Spectrograph Guaranteed Time Observations.

  11. Wireless sensor and data transmission needs and technologies for patient monitoring in the operating room and intensive care unit.

    Science.gov (United States)

    Paksuniemi, M; Sorvoja, H; Alasaarela, E; Myllyla, R

    2005-01-01

    In the intensive care unit, or during anesthesia, patients are attached to monitors by cables. These cables obstruct nursing staff and hinder the patients from moving freely in the hospital. However, rapidly developing wireless technologies are expected to solve these problems. To this end, this study revealed problem areas in current patient monitoring and established the most important medical parameters to monitor. In addition, usable wireless techniques for short-range data transmission were explored and currently employed wireless applications in the hospital environment were studied. The most important parameters measured of the patient include blood pressures, electrocardiography, respiration rate, heart rate and temperature. Currently used wireless techniques in hospitals are based on the WMTS and WLAN standards. There are no viable solutions for short-range data transmission from patient sensors to patient monitors, but potentially usable techniques in the future are based on the WPAN standards. These techniques include Bluetooth, ZigBee and UWB. Other suitable techniques might be based on capacitive or inductive coupling. The establishing of wireless techniques depends on ensuring the reliability of data transmission, eliminating disturbance by other wireless devices, ensuring patient data security and patient safety, and lowering the power consumption and price.

  12. Novel fringe scanning/Fourier transform method of synthetic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, T.M.; Albano, R.K.

    1993-08-01

    We have developed a one-dimensional theory and a computer model for synthetically imaging scenes using a novel fringe scanning/Fourier transform technique. Our method probes a scene using two interfering beams of slightly different frequency. These beams form a moving fringe pattern which scans the scene and resonates with any spatial frequency components having the same spatial frequency as the scanning fringe pattern. A simple, non-imaging detector above the scene observes any scattered radiation from the scene falling onto it. If a resonance occurs between the scanning fringe pattern and the scene, then the scattered radiation will be modulated at the difference frequency between the two probing beams. By changing the spatial period of the fringe pattern and then measuring the amplitude and phase of the modulated radiation that is scattered from the scene, the Fourier amplitudes and phases of the different spatial frequency components making up the scene can be measured. A synthetic image of the scene being probed can be generated from this Fourier amplitude and phase data by taking the inverse Fourier transform of this information. This technique could be used to image objects using light, ultrasonic, or other electromagnetic or acoustic waves.

  13. The quest for synergy when developing the urban fringe

    DEFF Research Database (Denmark)

    Hansen, Jesper Rohr; Engberg, Lars A.

    How can planning policies related to urban fringe development and disadvantaged neighbourhoods create synergy? This question is approached and answered by various research fields and explored on various urban-planning levels, displaying case-studies related to urban regeneration, post-industrial ......). Finally, the paper concludes, assessing whether the synergies of urban-fringe development have another character than more explicit ‘trickle-down’ strategies located in existing research of urban regeneration.......How can planning policies related to urban fringe development and disadvantaged neighbourhoods create synergy? This question is approached and answered by various research fields and explored on various urban-planning levels, displaying case-studies related to urban regeneration, post......-industrial and suburban development and urban fringe literature. The present paper adds to these discussions by analysing two case-studies in Denmark in which local government pursue traditional urban-growth strategies in urban-fringe development - a post-industrial harbour and a large suburb, located just outside...

  14. Δ B mechanism for fringe-field organic magnetoresistance

    Science.gov (United States)

    Cox, M.; Kersten, S. P.; Veerhoek, J. M.; Bobbert, P.; Koopmans, B.

    2015-04-01

    Fringe fields emanating from magnetic domain structures can give rise to magnetoresistance in organic semiconductors. In this article, we explain these magnetic-field effects in terms of a Δ B mechanism. This mechanism describes how variations in magnetic-field strength between two polaron hopping sites can induce a difference in precessional motion of the polaron spins, leading to mixing of their spin states. In order to experimentally explore the fringe-field effects, polymer thin-film devices on top of a rough in-plane magnetized cobalt layer are investigated. The cobalt layer can be described by a distribution of out-of-plane magnetic anisotropies, most likely induced by thickness variations in the cobalt. With a magnetic field perpendicular to the cobalt layer, fringe fields are created because some domains are magnetized out of plane whereas the magnetization of other domains remains approximately in plane. By varying the distance between the polymer layer and the cobalt layer, we find that the magnetoresistance arising from these fringe fields reduces with the gradient in the fringe fields, in agreement with the Δ B mechanism.

  15. DInSAR fringes simulation of sandbox models

    Science.gov (United States)

    Derron, Marc-Henri; Carrea, Dario; Michoud, Clément; Jaboyedoff, Michel

    2015-04-01

    Interpreting satellite DInSAR patterns of slope movements can be difficult because of unwrapping problems, loss of coherence or radar imaging geometry limitations (layover, shadowing …). We investigate the potential of simulating interferometric fringes as a tool to help understanding real DInSAR images. Various types of gravitational slope deformations (sliding, toppling …) have been produced in a sandbox in the lab. These experiments were monitored with a micro-lidar Minolta-Konika Vivid 9i to get successive Digital Elevation Models of the surface. A pair of DEM is then used to simulate DInSAR fringes patterns, with the possibility to vary the wavelength, the angle between the line of sight and the ground displacement, the look angle, the baseline, etc. DInSAR fringes simulated here are idealized. They are not affected by any noise, decoherence, layover or shadow effects; radar image deformations are computed in ancillary files. However it appears that even these ideal wrapped fringes patterns get rapidly very complex when deformation is strong. Then this kind of tool is of interest to better constrain ground surface deformations from resulting InSAR fringes (from lab models or real landslides data). It makes also possible to test how the acquisition geometry impacts the InSAR result depending on the type of slope movement considered.

  16. Beyond the Fringe: The Role of Recreation in Multi-Functional Urban Fringe Landscapes

    Directory of Open Access Journals (Sweden)

    Ian GILHESPY

    2013-12-01

    Full Text Available This paper reviews some of the academic literature and policy documents that relate to and promote the need for urban design and the re-invigoration of the processes and practices of ‘masterplanning’. Specifically, this paper concerns the implications for recreation in areas that have been conceptualised in a number of ways including ‘urban fringe’ and ‘fringe-belt’ and the ways in which these areas are being re-developed as multi-functional spaces in the planning process. The paper pays particular attention to the proposed development of the ‘North Plymouth Community Park’ examining the claims made for the sustainable characteristics of the development and questioning the absence of the cultural aspects of recreation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Haridas, Divya [Department of Physics, National Institute of Technology Calicut, Kerala, 673601 (India); P, Vibin Antony; Sajith, V.; Sobhan, C. B. [School of Nano Science and Technology, National Institute of Technology Calicut, Kerala, 673601 (India)

    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.

  18. VLTI First Fringes with Two Auxiliary Telescopes at Paranal

    Science.gov (United States)

    2005-03-01

    interferometric installation of this size and crucial for its exceptional performance. The ATs may be placed at 30 different positions and thus be combined in a very large number of ways. If the 8.2-m VLT Unit Telescopes are also taken into account, no less than 254 independent pairings of two telescopes ("baselines"), different in length and/or orientation, are available. Moreover, while the largest possible distance between two 8.2-m telescopes (ANTU and YEPUN) is about 130 metres, the maximal distance between two ATs may reach 200 metres. As the achievable image sharpness increases with telescope separation, interferometric observations with the ATs positioned at the extreme positions will therefore yield sharper images than is possible by combining light from the large telescopes alone. All of this will enable the VLTI to obtain exceedingly detailed (sharp) and very complete images of celestial objects - ultimately with a resolution that corresponds to detecting an astronaut on the Moon. Auxiliary Telescope no. 1 (AT1) was installed on the observatory's platform in January 2004. Now, one year later, the second of the four to be delivered, has been integrated into the VLTI. The installation period lasted two months and ended around midnight during the night of February 2-3, 2005. With extensive experience from the installation of AT1, the team of engineers and astronomers were able to combine the light from the two Auxiliary Telescopes in a very short time. In fact, following the necessary preparations, it took them only five minutes to adjust this extremely complex optical system and successfully capture the "First Fringes" with the VINCI test instrument! The star which was observed is named HD62082 and is just at the limit of what can be observed with the unaided eye (its visual magnitude is 6.2). The fringes were as clear as ever, and the VLTI control system kept them stable for more than one hour. Four nights later this exercise was repeated successfully with the mid

  19. Una técnica para filtrar patrones de fringing

    Science.gov (United States)

    Ostrov, P. G.

    Se presenta una nueva técnica para filtrar los patrones de fringing producidos en los CCDs tipo RCA. El método consiste en construir un mapa con los ángulos de inclinación de las franjas en cada punto de la imagen. Este mapa es ulteriormente utilizado para alinear con el patrón de interferencia una ventana estrecha, sobre la que se aplica un filtro de mediana. Este procedimiento permite eliminar la mayor parte del ruido del patrón de fringing sin destruirlo.

  20. Analytical expressions for fringe fields in multipole magnets

    Directory of Open Access Journals (Sweden)

    B. D. Muratori

    2015-06-01

    Full Text Available 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

  1. Phase extraction from fringe pattern via light propagation.

    Science.gov (United States)

    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.

  2. Encryption of 3D Point Cloud Object with Deformed Fringe

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2016-01-01

    Full Text Available A 3D point cloud object encryption method was proposed with this study. With the method, a mapping relationship between 3D coordinates was formulated and Z coordinate was transformed to deformed fringe by a phase coding method. The deformed fringe and gray image were used for encryption and decryption with simulated off-axis digital Fresnel hologram. Results indicated that the proposed method is able to accurately decrypt the coordinates and gray image of the 3D object. The method is also robust against occlusion attacks.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  4. Non-destructive 3D shape measurement of transparent and black objects with thermal fringes

    Science.gov (United States)

    Brahm, Anika; Rößler, Conrad; Dietrich, Patrick; Heist, Stefan; Kühmstedt, Peter; Notni, Gunther

    2016-05-01

    Fringe projection is a well-established optical method for the non-destructive contactless three-dimensional (3D) measurement of object surfaces. Typically, fringe sequences in the visible wavelength range (VIS) are projected onto the surfaces of objects to be measured and are observed by two cameras in a stereo vision setup. The reconstruction is done by finding corresponding pixels in both cameras followed by triangulation. Problems can occur if the properties of some materials disturb the measurements. If the objects are transparent, translucent, reflective, or strongly absorbing in the VIS range, the projected patterns cannot be recorded properly. To overcome these challenges, we present a new alternative approach in the infrared (IR) region of the electromagnetic spectrum. For this purpose, two long-wavelength infrared (LWIR) cameras (7.5 - 13 μm) are used to detect the emitted heat radiation from surfaces which is induced by a pattern projection unit driven by a CO2 laser (10.6 μm). Thus, materials like glass or black objects, e.g. carbon fiber materials, can be measured non-destructively without the need of any additional paintings. We will demonstrate the basic principles of this heat pattern approach and show two types of 3D systems based on a freeform mirror and a GOBO wheel (GOes Before Optics) projector unit.

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

    Science.gov (United States)

    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)

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

    Science.gov (United States)

    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)

  7. Real-time 3-D shape measurement with composite phase-shifting fringes and multi-view system.

    Science.gov (United States)

    Tao, Tianyang; Chen, Qian; Da, Jian; Feng, Shijie; Hu, Yan; Zuo, Chao

    2016-09-01

    In recent years, fringe projection has become an established and essential method for dynamic three-dimensional (3-D) shape measurement in different fields such as online inspection and real-time quality control. Numerous high-speed 3-D shape measurement methods have been developed by either employing high-speed hardware, minimizing the number of pattern projection, or both. However, dynamic 3-D shape measurement of arbitrarily-shaped objects with full sensor resolution without the necessity of additional pattern projections is still a big challenge. In this work, we introduce a high-speed 3-D shape measurement technique based on composite phase-shifting fringes and a multi-view system. The geometry constraint is adopted to search the corresponding points independently without additional images. Meanwhile, by analysing the 3-D position and the main wrapped phase of the corresponding point, pairs with an incorrect 3-D position or a considerable phase difference are effectively rejected. All of the qualified corresponding points are then corrected, and the unique one as well as the related period order is selected through the embedded triangular wave. Finally, considering that some points can only be captured by one of the cameras due to the occlusions, these points may have different fringe orders in the two views, so a left-right consistency check is employed to eliminate those erroneous period orders in this case. Several experiments on both static and dynamic scenes are performed, verifying that our method can achieve a speed of 120 frames per second (fps) with 25-period fringe patterns for fast, dense, and accurate 3-D measurement.

  8. Engaging Fringe Stakeholders in Business and Society Research

    DEFF Research Database (Denmark)

    McCarthy, Lauren; Muthuri, Judy N.

    2016-01-01

    Business and society (B&S) researchers, as well as practitioners, have been critiqued for ignoring those with less voice and power (e.g., women, nonliterate, or indigenous peoples) often referred to as “fringe stakeholders.” Existing methods used in B&S research often fail to address issues of me...

  9. Modelling wave transformation across a fringing reef using swash

    NARCIS (Netherlands)

    Zijlema, M.

    2012-01-01

    This paper presents the application of the open source non-hydrostatic wave-flow model SWASH to wave propagation over a fringing reef, and the results are discussed and compared with observations obtained from a laboratory experiment subjected to various incident wave conditions. This study focus no

  10. Modelling wave transformation across a fringing reef using SWASH

    NARCIS (Netherlands)

    Zijlema, M.

    2012-01-01

    This paper presents the application of the open source non-hydrostatic wave-flow model SWASH to wave propagation over a fringing reef, and the results are discussed and compared with observations obtained from a laboratory experiment subjected to various incident wave conditions. This study focus no

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

    Science.gov (United States)

    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.

  12. Children on the Fringe: "Oliver Twist" without the Music.

    Science.gov (United States)

    Barron, Daniel D.

    1998-01-01

    Argues that school library media specialists have a role to play in exposing the world of children on the fringes of society. Describes selected resources for teachers and older students, as well as books for students that focus on this theme. (AEF)

  13. 26 CFR 1.61-21 - Taxation of fringe benefits.

    Science.gov (United States)

    2010-04-01

    ... 117(d)); meals or lodging furnished to an employee for the convenience of the employer (section 119... partner, director, or an independent contractor. For convenience, the term “employee” includes any person... employer of the recipient of the fringe benefit, but may be, for example, a client or customer of...

  14. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or...

  15. 29 CFR 4.50 - Types of wage and fringe benefit determinations.

    Science.gov (United States)

    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,...

  16. 29 CFR 4.54 - Locality basis of wage and fringe benefit determinations.

    Science.gov (United States)

    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...

  17. 29 CFR 4.176 - Payment of fringe benefits to temporary and part-time employees.

    Science.gov (United States)

    2010-07-01

    ... week (40 hours) paid vacation under the applicable fringe benefit determination, then the part-time... pension benefits specified in the applicable fringe benefit determination. Thus, if the determination... 29 Labor 1 2010-07-01 2010-07-01 true Payment of fringe benefits to temporary and...

  18. 29 CFR 4.165 - Wage payments and fringe benefits-in general.

    Science.gov (United States)

    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...

  19. 29 CFR 4.172 - Meeting requirements for particular fringe benefits-in general.

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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…

  1. ZnO coated Fabry-Perot interferometric optical fiber for detection of gasoline blend vapors: Refractive index and fringe visibility manipulation studies

    Science.gov (United States)

    Pawar, Dnyandeo; Kitture, Rohini; Kale, S. N.

    2017-03-01

    ZnO nanoparticles-coated Fabry-Perot interferometer based optical fiber sensor is demonstrated to detect different gasoline blend concentrations in ethanol. Different gasoline blends (with ethanol varying from 0% (E0) to 100% (E100)) have been subjected to the sensor to observe the change in refractive index of the material that leads to the wavelength shift and fringe visibility change of the interference spectrum. The sensor shows the remarkable response with different gasoline blend mixtures within the time span of 0-60 s in terms of wavelength and Intensity (power) shift. The maximum wavelength shift of 12.1 nm is observed for E0 mixture and least of 3 nm for E100 in 60 s, respectively. A fast response time and recovery time of 5 s and 9 s, respectively, are obtained for E0 mixture. The results are related to the formation of interference pattern due the ZnO-mediated-Fabry-Perot cavity, changes in refractive index with the change in external gaseous environment, changes in fringe visibility of the spectrum and the interaction of oxygen vacancies on ZnO surface with the gasoline moieties. The rates of sensing and recovery times are related to the Reid vapor pressures of ethanol and gasoline. Hence a dual scale of sensing, both in terms of wavelength shift (refractive index) and intensity shift (fringe visibility) has been proposed for gasoline blend sensing.

  2. Racial Differences in Fringe Benefits and Compensation

    OpenAIRE

    Mok, Wallace; Siddique, Zahra

    2009-01-01

    This paper examines differences in two important components of non-wage compensation, employer provided health insurance and pensions, across African Americans and the whites in the United States. Using data from the Current Population Survey (CPS) and the National Longitudinal Survey of Youth (NLSY), we study the recent trends in the recipiency of this non-wage compensation across race groups. Our results show that African American men on average are significantly less likely to receive empl...

  3. Identification and Spatial Distribution of Remotely Sensed Sand on Fringing Reefs of Oahu, Hawaii

    Science.gov (United States)

    Conger, C. L.; Fletcher, C. H.; Hochberg, E. J.

    2004-12-01

    What surficial spatial patterns predominate among sand accumulations on fringing reefs? Do these patterns provide clues to transport mechanisms and factors governing deposition? Understanding of these spatial characteristics is integral for studying sand as a resource, a benthic habitat, and a mobile geologic unit on the sea floor. Using Quickbird imagery of fringing reefs on Oahu, Hawaii, we tested multiple data processing techniques with a linear classifier that utilized a fixed set of training groups and a truth image. Results show the Lyzenga method provided the best quantitative results, and analyst review finds this method to be the best qualitative spatial display as well. Highly accurate spatial data produced from the classified image, combined with bathymetry data from Shoals LIDAR were then utilized to begin identifying spatial distribution of the sandy substrate across the sea floor. Using basic geomorphologic reef descriptions and general spatial characteristics of the sandy substrate is the first step in identifying patterns of distribution within and juxtaposition to the reef. These results, when compiled from several sites, may begin to provide better understanding of sand's role in the reef geomorphology, though current results are not yet sufficient for predicting sandy substrate characteristics from remotely sensed data.

  4. A Compact Energy Harvesting System for Outdoor Wireless Sensor Nodes Based on a Low-Cost In Situ Photovoltaic Panel Characterization-Modelling Unit.

    Science.gov (United States)

    Antolín, Diego; Medrano, Nicolás; Calvo, Belén; Martínez, Pedro A

    2017-08-04

    This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units-characterization and modelling-are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc. Experimental comparison to a classical pilot panel based VOC algorithm show better efficiency under the same tested conditions.

  5. Nanocrystal Phase Identification by Lattice Fringe Fingerprinting from High Resolution Transmission Electron Microscope Images

    Science.gov (United States)

    Bjorge, Ruben; Seipel, Bjoern; Moeck, Peter; Fraundorf, Philip

    2006-05-01

    Lattice fringe fingerprinting is a novel and powerful method of identifying and characterizing nanocrystalline structures or materials based on images from direct space high-resolution transmission electron microscopy (HRTEM). We examine Fourier transformed HRTEM images of nanocrystals in certain orientations (i.e. lattice fringes and cross fringes) in order to obtain a lattice fringe fingerprint plot. Such plots are used to identify a crystalline nanoparticle by comparing the experimental data with data that are derived from a comprehensive database. A lattice fringe fingerprint plot is similar to a classical X-ray powder diffractogram, but an important advantage is that the intersection angles of lattice fringes give us additional information. When transmission electron microscope image acquisition and data interpretation are automated and connected to a comprehensive database (such as our Nano-Crystallography Database, http://nanocrystallography.research.pdx.edu/), fringe fingerprinting will be able to compete with powder X-ray diffraction in identifying unknown nanocrystals on a routine basis.

  6. Coherence Enhancing Diffusion and Windowed Fourier Filtering for Fringe Patterns Denoising (II)

    Science.gov (United States)

    Wang, Haixia; Kemao, Qian

    2010-04-01

    Fringe patterns produced by various optical interferometric techniques encode the information of deformation, refractive index, vibration, etc. Noise as one of the key problems affects further processing of the fringe patterns and reduces the final measurement quality. Coherence enhancing diffusion (CED) is a partial differential equation based denoising model that suppresses the noise as well as preserves the flow-like structure. Windowed Fourier transform-based windowed Fourier filtering (WFF) is another useful fringe pattern denoising tool that removes noise by thresholding the windowed Fourier transform spectrum. An adaptive windowed Fourier filtering (AWFF) that denoises the fringe pattern based on pixels' local frequencies is proposed in this paper. The performance of AWFF is compared with WFF and CED by applying them to fringe patterns that contain speckle noise and different levels of frequencies. Quantitative results will be given on simulated fringe patterns. Experimental fringe pattern will also be tested to illustrate the performance of these methods.

  7. Note: Optical fiber milled by focused ion beam and its application for Fabry-Pérot refractive index sensor

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Wang, Fei; Savenko, Alexey;

    2011-01-01

    We introduce a highly compact fiber-optic Fabry-Pérot refractive index sensor integrated with a fluid channel that is fabricated directly near the tip of a 32 μm in diameter single-mode fiber taper. The focused ion beam technique is used to efficiently mill the microcavity from the fiber side...... and finely polish the end facets of the cavity with a high spatial resolution. It is found that a fringe visibility of over 15 dB can be achieved and that the sensor has a sensitivity of ∼1731 nm/RIU (refractive index units) and a detection limit of ∼5.78 × 10−6 RIU. This miniature integrated all-in-fiber...

  8. The Ecology of Fringe Science and its Bearing on Policy

    CERN Document Server

    Collins, HM; Reyes-Galindo, LI

    2016-01-01

    In this paper we illustrate the tension between mainstream 'normal', 'unorthodox' and 'fringe' science that is the focus of two ongoing projects that are analysing the full ecology of physics knowledge. The first project concentrates on empirically understanding the notion of consensus in physics by investigating the policing of boundaries that is carried out at the arXiv preprint server, a fundamental element of the contemporary physics publishing landscape. The second project looks at physics outside the mainstream and focuses on the set of organisations and publishing outlets that have mushroomed outside of mainstream physics to cover the needs of 'alternative', 'independent' and 'unorthodox' scientists. Consolidating both projects into the different images of science that characterise the mainstream (based on consensus) and the fringe (based on dissent), we draw out an explanation of why today's social scientists ought to make the case that, for policy-making purposes, the mainstream's consensus should be...

  9. Study of Lau fringes generated by a photorefractive volume grating

    Science.gov (United States)

    Forte, Gustavo; Tebaldi, Myrian; Bolognini, Nestor

    2017-08-01

    In this work the Lau fringes generated by using a combination of an amplitude grating and a photorefractive volume phase grating is theoretically and experimentally analyzed. A model based on the path integral formalism to calculate the patterns intensity is employed. We show that the Lau pattern behavior is governed by the output pupil diameter of the imaging recording system, the DC external electric field and the crystal thickness. The introduction of a phase modulation that gathers the previously mentioned parameters allows determining the condition to optimize the fringe visibility. In this case, the visibility maintains a sinusoidal dependence as it happened with planar grating experiments. The experimental results confirm the theoretical model proposed.

  10. Advanced split-illumination electron holography without Fresnel fringes

    Energy Technology Data Exchange (ETDEWEB)

    Tanigaki, Toshiaki, E-mail: tanigaki-toshiaki@riken.jp [Center for Emergent Matter Science (CEMS), RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Aizawa, Shinji; Park, Hyun Soon [Center for Emergent Matter Science (CEMS), RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Harada, Ken [Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan); Shindo, Daisuke [Center for Emergent Matter Science (CEMS), RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan)

    2014-02-01

    Advanced split-illumination electron holography was developed by employing two biprisms in the illuminating system to split an electron wave into two coherent waves and two biprisms in the imaging system to overlap them. A focused image of an upper condenser-biprism filament was formed on the sample plane, and all other filaments were placed in its shadow. This developed system makes it possible to obtain precise reconstructed object waves without modulations due to Fresnel fringes, in addition to holograms of distant objects from reference waves. - Highlights: • Advanced split-illumination electron holography without Fresnel fringes is developed. • Two biprisms are installed in illuminating system of microscope. • High-precision holographic observations of an area locating far from the sample edge become possible.

  11. Wrapped statistics-based phase retrieval from interference fringes

    Science.gov (United States)

    Waghmare, Rahul G.; Sai Subrahmanyam Gorthi, R. K.; Mishra, Deepak

    2016-08-01

    We propose a wrapped statistics-based approach for phase estimation from noisy reconstructed interference fringes in digital holographic interferometry. The state space model required here is formed by Taylor series expansion of the phase function as state model and the wrapped dynamical system as measurement model. Prediction of the state using Kalman filter is straightforward since the state model is linear. However, the non-linearity issue induced due to the wrapping of the measurements is handled by changing the innovation correction step, which accounts for the probability of wrappings. Through the simulation and experimental study, we have shown that the proposed approach is robust to both, noise in fringe pattern as well as the dynamic range of the phase pattern, simultaneously. Moreover, it outperforms when compared with the other state-of-the-art phase retrieval approaches.

  12. Structured light system calibration method with optimal fringe angle.

    Science.gov (United States)

    Li, Beiwen; Zhang, Song

    2014-11-20

    For structured light system calibration, one popular approach is to treat the projector as an inverse camera. This is usually performed by projecting horizontal and vertical sequences of patterns to establish one-to-one mapping between camera points and projector points. However, for a well-designed system, either horizontal or vertical fringe images are not sensitive to depth variation and thus yield inaccurate mapping. As a result, the calibration accuracy is jeopardized if a conventional calibration method is used. To address this limitation, this paper proposes a novel calibration method based on optimal fringe angle determination. Experiments demonstrate that our calibration approach can increase the measurement accuracy up to 38% compared to the conventional calibration method with a calibration volume of 300(H)  mm×250(W)  mm×500(D)  mm.

  13. Complex fringes around magnetite porphyroclasts: growth and deformation history.

    OpenAIRE

    Lagoeiro, Leonardo Evangelista; Barbosa, Paola Ferreira; Fueten, Frank

    2011-01-01

    Deformed strain fringes in iron formation rocks show complex quartz fiber patterns that grew alongside magnetite porphyroclasts embedded in a matrix of quartz and iron oxides during coaxial to non-coaxial deformation. These rocks have been deformed by a combination of processes involving microfracturing, pressure solution and dislocation glide at temperatures of approximately 300 °C. Detailed microstructural observation and crystallographic analysis show that quartz fiber growth is not contro...

  14. A quantum radar detection protocol for fringe visibility enhancement

    Science.gov (United States)

    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.

  15. SFFT based phase demodulation for faster interference fringes analysis

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Settlement Dynamics In The Northern Fringes Of Port Harcourt Metropolis

    Directory of Open Access Journals (Sweden)

    Ibama Brown

    2015-05-01

    Full Text Available ABSTRACT Growth in Port Harcourt has been experienced in terms of population and space. However while some settlements in the northern fringes of Port Harcourt metropolis are growing rapidly some are almost stagnant if not shrinking. This work has identified reasons why Port Harcourt is growing towards the north factors for changes in population land-use and infrastructure the magnitude of the changes in population and infrastructure have been identified the role of both the public and private sector in addressing the issue of rapid growth of settlements that are immerging as the bigger settlements in an unplanned and uncontrollable way have been discussed. Questionnaires were administered oral interviews were conducted and personal observations helped in gathering information about the study area. Findings indicates that there is correlation between population and infrastructural development some settlements are densely populated while others are sparsely populated some settlements need facilities that will cause multipliers effect while others need facilities that will serve their basic needs. People are moving to the northern fringes of Port Harcourt metropolis because land is available less expensive and the topography encourages infrastructural development. This work has assessed the dynamics of settlements in the northern fringes of Port Harcourt metropolis by looking at changes in population and infrastructure.

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

    Science.gov (United States)

    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.

  19. Effect of fringe divergence in fluid acceleration measurement using LDA

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Se Jong; Sung, Hyung Jin [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Nobach, Holger; Tropea, Cam [Technische Universitat Darmstadt, Darmstadt (Germany)

    2004-07-01

    The laser Doppler technique is well-established as a velocity measurement technique of high precision for flow velocity. Recently, the laser Doppler technique has also been used to measure acceleration of fluid particles. Acceleration is interesting from a fluid mechanics point of view, since the Navier Stokes equations, specifically the left-hand-side, are formulated in terms of fluid acceleration. Further, there are several avenues to estimating the dissipation rate using the acceleration. However such measurements place additional demands on the design of the optical system; in particular fringe non-uniformity must be held below about 0.0001 to avoid systematic errors. Relations expressing fringe divergence as a function of the optical parameters of the system have been given in the literature; however, direct use of these formulae to minimize fringe divergence lead either to very large measurement volumes or to extremely high intersection angles. This dilemma can be resolved by using an off-axis receiving arrangement, in which the measurement volume is truncated by a pinhole in front of the detection plane. In the present study an optical design study is performed for optimizing laser Doppler systems for fluid acceleration measurements. This is followed by laboratory validation using a round free jet and a stagnation flow, two flows in which either fluid acceleration has been previously measured or in which the acceleration is known analytically. A 90 degree off-axis receiving angle is used with a pinhole or a slit.

  20. Sensors and actuators, Twente

    NARCIS (Netherlands)

    Bergveld, P.

    1989-01-01

    This paper describes the organization and the research programme of the Sensor and Actuator (S&A) Research Unit of the University of Twente, Enschede, the Netherlands. It includes short descriptions of all present projects concerning: micromachined mechanical sensors and actuators, optical sensors,

  1. Improved Spectral Resolution of Long-Period Fiber Grating Sensors for Ultra-High Temperature Environments Using Narrow Interferences between Regenerated Gratings

    DEFF Research Database (Denmark)

    Kristensen, Martin; Russell, J; Gao, Shaorui;

    2014-01-01

    The advantages of D-shape fiber in combination with an optical analog of Ramsey fringes using LPGs are presented. The mode-profiles of the sensor were characterized experimentally to provide deeper knowledge about improved functionality....

  2. Biomechanical jumping differences among elite female handball players with and without previous anterior cruciate ligament reconstruction: a novel inertial sensor unit study.

    Science.gov (United States)

    Setuain, Igor; Millor, Nora; González-Izal, Miriam; Gorostiaga, Esteban M; Gómez, Marisol; Alfaro-Adrián, Jesús; Maffiuletti, Nicola A; Izquierdo, Mikel

    2015-09-01

    Persistent biomechanical and jumping capacity alterations have been observed among female athletes who have sustained anterior cruciate ligament (ACL) injuries. The purpose of this study was to examine if biomechanical jumping differences persist among a cohort of elite female handball players with previous ACL reconstruction several years after return to top-level competition. In order to achieve this goal, a direct mechanics simplified analysis by using a single Inertial Sensor Unit (IU) was used. Twenty-one elite female (6 anterior cruciate ligament reconstructed and 15 uninjured control players) handball players were recruited and evaluated 6.0 ± 3.5 years after surgical anterior cruciate ligament reconstruction. Bilateral and unilateral vertical jumps were performed to evaluate the functional performance and a single inertial sensor unit was employed in order to collect 3D acceleration and 3D orientation data. Previously ACL-reconstructed analysed athletes demonstrated significant (p reconstruction. Identification of the encountered deficits through the use of an IU devise could provide clinicians with a new reliable tool for movement analysis in a clinical setting.

  3. Evaluation of wildfire patterns at the wildland-urban fringe across the continental U.S.

    Science.gov (United States)

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

    2014-12-01

    Wildfires threaten ecosystems and urban development across the United States, posing significant implications for land management and natural processes such as watershed hydrology. This study investigates the spatial association between large wildfires and urbanization. Several geospatial dataset are combined to map wildfires (Monitoring Trends in Burn Severity for 1984 to 2012) and housing density (SILVIS Lab Spatial Analysis for Conservation and Sustainability decadal housing density for 1940 to 2030) relative to natural wildlands across the contiguous U.S. Several buffers (i.e. 25 km) are developed around wildlands (Protected Areas Database of the United States) to quantify the change and relationship in spatial fire and housing density patterns. Since 1984, wildfire behavior is cyclical and follows general climatology, where warmer years have more and larger fires. Ignition locations also follow transportation corridors and development which provide easy accessibility to wildlands. In California, both fire frequency and total acres burned exhibit increasing trends (statistically significant at 95%). The 1980s average wildfire frequency and total acres burned was 3100 fires and approximately 1200 km2, respectively. These numbers have increased to 2200 fires and over 1500 km2 in the 2010 to 2012 period alone. Initial observations also show that decennial population and area burned for four major Californian counties (Los Angeles, San Bernardino, San Diego, and Shasta) show strong correlation between the last decade of burned area, urban-fringe proximity, and urbanization trends. Improving our understanding of human induced wildfire regimes provides key information on urban fringe communities most vulnerable to the wildfire risks and can help inform regional development planning.

  4. Displacement sensor containing magnetic field sensing element between a pair of biased magnets movable as a unit

    Science.gov (United States)

    Bahr, Joseph K. (Inventor); Johnson, Mont A. (Inventor)

    2003-01-01

    A displacement sensor for providing an indication of the position of a first body relative to a second body, the first body being displaceable relative to the second body in a displacement direction. The sensor is composed of: two magnets that are spaced from one another in the displacement direction to define therebetween a region containing a magnetic field; a magnetic field sensing element mounted in the region; and components for coupling at least one of the magnets to one of the bodies and the magnetic field sensing element to the other of the bodies to produce a relative displacement between the at least one magnet and the magnetic field sensing element in the displacement direction in response to displacement of the first body relative to the second body.

  5. Development of an Exhaled Breath Monitoring System with Semiconductive Gas Sensors, a Gas Condenser Unit, and Gas Chromatograph Columns

    Directory of Open Access Journals (Sweden)

    Toshio Itoh

    2016-11-01

    Full Text Available Various volatile organic compounds (VOCs in breath exhaled by patients with lung cancer, healthy controls, and patients with lung cancer who underwent surgery for resection of cancer were analyzed by gas condenser-equipped gas chromatography-mass spectrometry (GC/MS for development of an exhaled breath monitoring prototype system involving metal oxide gas sensors, a gas condenser, and gas chromatography columns. The gas condenser-GC/MS analysis identified concentrations of 56 VOCs in the breath exhaled by the test population of 136 volunteers (107 patients with lung cancer and 29 controls, and selected four target VOCs, nonanal, acetoin, acetic acid, and propanoic acid, for use with the condenser, GC, and sensor-type prototype system. The prototype system analyzed exhaled breath samples from 101 volunteers (74 patients with lung cancer and 27 controls. The prototype system exhibited a level of performance similar to that of the gas condenser-GC/MS system for breath analysis.

  6. Development of an Exhaled Breath Monitoring System with Semiconductive Gas Sensors, a Gas Condenser Unit, and Gas Chromatograph Columns.

    Science.gov (United States)

    Itoh, Toshio; Miwa, Toshio; Tsuruta, Akihiro; Akamatsu, Takafumi; Izu, Noriya; Shin, Woosuck; Park, Jangchul; Hida, Toyoaki; Eda, Takeshi; Setoguchi, Yasuhiro

    2016-11-10

    Various volatile organic compounds (VOCs) in breath exhaled by patients with lung cancer, healthy controls, and patients with lung cancer who underwent surgery for resection of cancer were analyzed by gas condenser-equipped gas chromatography-mass spectrometry (GC/MS) for development of an exhaled breath monitoring prototype system involving metal oxide gas sensors, a gas condenser, and gas chromatography columns. The gas condenser-GC/MS analysis identified concentrations of 56 VOCs in the breath exhaled by the test population of 136 volunteers (107 patients with lung cancer and 29 controls), and selected four target VOCs, nonanal, acetoin, acetic acid, and propanoic acid, for use with the condenser, GC, and sensor-type prototype system. The prototype system analyzed exhaled breath samples from 101 volunteers (74 patients with lung cancer and 27 controls). The prototype system exhibited a level of performance similar to that of the gas condenser-GC/MS system for breath analysis.

  7. Field test of a multi-frequency electromagnetic induction sensor for the study of soil moisture in different land-soil units

    Science.gov (United States)

    Calamita, Giuseppe; Onorati, Beniamino; Perrone, Angela; Manfreda, Salvatore; Brocca, Luca

    2015-04-01

    appealing compared to satellite remote sensing (RS) methods. However, similarly to RS, the interpretation of the EMI measurements is not straightforward due to the simultaneous influence of different soil properties. So far, the great majority of the studies have used mono-frequency EMI sensors for periods of time shorter than one year. Moreover studies over area with medium to high vegetation density are still quite rare. The focus of this work is to evaluate the usability of the GEM-300 multi-frequency EMI sensor for spatial and temporal SM retrieval at the hillslope scale over a number of diverse land-soil units including some of the less explored types, like highland forested areas. Further, some aspects relating to the inherent stability of the GEM-300 sensor, which were never addressed before in this research area, are also explored. The test sites are located in the "Fiumarella di Corleto" experimental basin, located in Basilicata region (southern Italy). The experimentation lasted from May 2012 to May 2013. Regular grids (80 x 80 mq) and a transect (60 m) were used as spatial sampling schemes. A TDR mobile probe was used for SM measurements on the 25 points of each grid whereas fixed buried TDR probes were used on the 11 points of transect. The obtained results allowed us to investigate the spatial and temporal variability and relation between TDR and EMI sensors.

  8. Research and development of a stabilizing holographic interference fringe system based on linear CCD

    Science.gov (United States)

    Li, Chaoming; Chen, Xinrong; Wu, Jianhong; Ju, Jianzhi; Zhu, Yayi; Hu, Zuyuan

    2009-07-01

    A method that is to stabilize holographic interference fringe during holographic recording process is put forward in this paper. As the kernel of this method, a negative feedback system based on linear CCD and piezoelectric ceramics (PZT) which is used to compensate the interference fringe random drift caused by various external vibrations in long time recording process was introduced in details. The proportion-integral-derivative method (PID) is adopted to control the moving of PZT which is used to compensate the drift of the interference fringes accurately. Thus the interference fringe can be frozen. Experiment results shows that this negative feedback system by controlling the optical path difference can effectively compensate the interference fringe random drift caused by various external vibrations in long time recording process. After using this system, the mean squared error of the interference fringe drift value can be under λ / 60 and the quality of the holographic grating is improved greatly.

  9. A novel method to obtain electronic speckle pattern interferometry fringe patterns with high contrast

    Institute of Scientific and Technical Information of China (English)

    Mengwei Li; Chen Tang; Gao Wang; Hongwei Ren; Ke Tang; Tianyu Ye

    2009-01-01

    Traditional speckle fringe patterns of electronic speckle pattern interferometry(ESPI)are obtained by adding,subtracting,or multiplying the speckle patterns recorded before and after the deformation.However,these speckle fringe patterns are of limited visibility,especially for addition and multiplication fringe patterns.We propose a novel method to obtain speckle fringe patterns of ESPI from undeformed and deformed speckle patterns.The fringe pattern generated by our method is of high contrast and has better quality than subtraction fringe.The new method is simple and does not require more computational effort.The proposed method is tested on the experimentally obtained undeformed and deformed speckle patterns.The experimental results illustrate the performance of this approach.

  10. Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system.

    Science.gov (United States)

    Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Bennett, N Robert; Pelc, Norbert; Fahrig, Rebecca

    2013-02-01

    Using hybrid x-ray∕MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine

  11. Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Lillaney, Prasheel; Pelc, Norbert [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Shin Mihye [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Hinshaw, Waldo; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Bennett, N. Robert [Department of Radiology, Stanford University, Stanford, California 94305 and Qualcomm MEMS Technologies, San Jose, California 95134 (United States)

    2013-02-15

    Purpose: Using hybrid x-ray/MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. Methods: The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also

  12. Optical sensor technology for simultaneous measurement of particle speed and concentration of micro sized particles

    DEFF Research Database (Denmark)

    Clausen, Casper; Han, Anpan; Kristensen, Martin

    2013-01-01

    Experimental characterization of a sensor technology that can measure particle speed and concentration simultaneously in liquids and gases is presented here. The basic sensor principle is based on an optical element that shapes a light beam into well-defined fringes. The technology can be described...... independently from particle speeds and is a key advantage compared to normal Laser Particle Counters....

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

    Science.gov (United States)

    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...

  14. Removal of Spectro-Polarimetric Fringes by 2D Pattern Recognition

    OpenAIRE

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

    2012-01-01

    We present a pattern-recognition based approach to the problem of removal of polarized fringes from spectro-polarimetric data. We demonstrate that 2D 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...

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

    Science.gov (United States)

    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.

  16. Partial-differential-equation-based coherence-enhancing denoising for fringe patterns

    Science.gov (United States)

    Wang, Haixia; Qian, Kemao; Gao, Wenjing; Lin, Feng; Seah, Hock Soon

    2008-11-01

    Fringe patterns produced by electronic speckle pattern interferometry (ESPI) are evaluated to measure the deformation on object surfaces. Noise is one of the key problems affecting further processing of the fringe patterns and reduces the final measurement quality. This paper presents a partial differential equations (PDEs) based coherence enhancing denoising model to reduce the noise, enhance the flow-like structure and improve the image quality of fringe patterns. Experimental results show that this filter is flexible and capable of removing most of the noise in ESPI fringe patterns.

  17. Transport of volatile organic compounds across the capillary fringe

    Science.gov (United States)

    McCarthy, Kathleen A.; Johnson, Richard L.

    1993-01-01

    Physical experiments were conducted to investigate the transport of a dissolved volatile organic compound (trichloroethylene, TCE) from shallow groundwater to the unsaturated zone under a variety of conditions including changes in the soil moisture profile and water table position. Experimental data indicated that at moderate groundwater velocities (0.1 m/d), vertical mechanical dispersion was negligible and molecular diffusion was the dominant vertical transport mechanism. Under these conditions, TCE concentrations decreased nearly 3 orders of magnitude across the capillary fringe and soil gas concentrations remained low relative to those of underlying groundwater. Data collected during a water table drop showed a short-term increase in concentrations throughout most of the unsaturated zone, but these concentrations quickly declined and approached initial values after the water table was returned to its original level. In the deep part of the unsaturated zone, the water table drop resulted in a long-term decrease in concentrations, illustrating the effects of hysteresis in the soil moisture profile. A two-dimensional random walk advection-diffusion model was developed to simulate the experimental conditions, and numerical simulations agreed well with experimental data. A simpler, one-dimensional finite-difference diffusion-dispersion model was also developed. One-dimensional simulations based on molecular diffusion also agreed well with experimental data. Simulations which incorporated mechanical dispersion tended to overestimate flux across the capillary fringe. Good agreement between the one- and two-dimensional models suggested that a simple, one-dimensional approximation of vertical transport across the capillary fringe can be useful when conditions are appropriate.

  18. Fringe pattern analysis for optical metrology theory, algorithms, and applications

    CERN Document Server

    Servin, Manuel; Padilla, Moises

    2014-01-01

    The main objective of this book is to present the basic theoretical principles and practical applications for the classical interferometric techniques and the most advanced methods in the field of modern fringe pattern analysis applied to optical metrology. A major novelty of this work is the presentation of a unified theoretical framework based on the Fourier description of phase shifting interferometry using the Frequency Transfer Function (FTF) along with the theory of Stochastic Process for the straightforward analysis and synthesis of phase shifting algorithms with desired properties such

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

    Science.gov (United States)

    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

  20. Optical/Digital Fringe Multiplication in Projection Moiré

    Institute of Scientific and Technical Information of China (English)

    MAO Ling-tao; AN Li-qian; FANG Cui-chang

    2004-01-01

    In this paper, the optical/digital fringe multiplication (O/DFM) is realized in projection moiré using digital image processing (DIP). Both deformed grating and reference grating are captured using a CCD camera. The reference grating can also be produced using DIP. With the O/DFM, the pattern is multiplied with an image processing software, which is developed using MATLAB 6.5. Also with DIP, the phase shifting can become much simpler, and the automation can be adopted. The multiplied pattern is much thinner and easier to read, and sensitivity of measurement can be enhanced.

  1. Engaging Fringe Stakeholders in Business and Society Research

    DEFF Research Database (Denmark)

    McCarthy, Lauren; Muthuri, Judy N.

    2016-01-01

    Business and society (B&S) researchers, as well as practitioners, have been critiqued for ignoring those with less voice and power (e.g., women, nonliterate, or indigenous peoples) often referred to as “fringe stakeholders.” Existing methods used in B&S research often fail to address issues...... methods may be used by researchers to achieve more inclusive, and thus more credible, stakeholder research that can improve decision making within businesses. Furthermore, we argue that ingrained social and environmental problems tackled by B&S research and the unique context in which they occur may open...

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

    Science.gov (United States)

    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

  3. SIMULTANEOUS RECORDING OF FRINGE PATTERNS WITH ONE CAMERA

    Institute of Scientific and Technical Information of China (English)

    SU Fei; DAI Fulong; CHIAN Kerm Sin; YI Sung

    2004-01-01

    A novel method to separate and simultaneously record the Moiré interferometry fringe patterns of three deformation fields with only one CCD camera is developed; details of its operation principle, key points and error analysis are presented. With this technique, the deformation in U, V and W fields can be measured simultaneously, so dynamic test with comprehensive information can be performed. The advantage of this technique over other similar techniques lies in its simplicity, easy implementation and low cost. An application of this technique is given to show its feasibility. Technical problems that may be caused with this technique are also analyzed.

  4. Influence of cavity loss on an extrinsic Fabry-Perot cavity intensity-based pressure sensor.

    Science.gov (United States)

    Lű, Tao

    2015-09-01

    We present an extrinsic Fabry-Perot cavity intensity-based pressure sensor that mainly comprises a single-mode fiber end and an elastic monocrystalline silicon layer bonded to a silicon diaphragm. We investigated the influence of cavity loss on the performance indexes (PIS) of the intensity-based extrinsic Fabry-Perot cavity optical fiber pressure sensor. A buffer unit made of three incompressible oil cavities attenuated outside pressure and transformed pressure information into cavity length microchange information. Experimental results indicated that, under center quadrature-points within the linear regions of adjacent fringes, for an applied 40 kPa external pressure, cavity length was modulated by pressures of 69.9 kPa-109.9 kPa, 150.1 kPa-190 kPa, 220.1 kPa-259.9 kPa, and 279.9 kPa-319.9 kPa, output intensity ranges increased as 1 μW, 1.02 μW, 1.03 μW, and 1.05 μW, sensitivity increased as 0.01909 μW/kPa, 0.01986 μW/kPa, 0.02127 μW/kPa, and 0.02387 μW/kPa, but linearity degraded, as indicated by the standard deviation of linear fits of 0.02607, 0.02664, 0.02935, and 0.04879 due to cavity loss. Furthermore, the pressure ranges within the same quarter period decreased as 40 kPa, 37.45 kPa, 32.4 kPa, and 30.15 kPa. Consequently, the same lengths of linear regions within adjacent fringes of an approximately sinusoidal curve corresponded to different measurement ranges, linearities, and sensitivities. Initial cavity length must be chosen to optimize both signal strength and the PIS studied here in manufacturing this type sensor.

  5. Measurement uncertainty budget of an interferometric flow velocity sensor

    Science.gov (United States)

    Bermuske, Mike; Büttner, Lars; Czarske, Jürgen

    2017-06-01

    Flow rate measurements are a common topic for process monitoring in chemical engineering and food industry. To achieve the requested low uncertainties of 0:1% for flow rate measurements, a precise measurement of the shear layers of such flows is necessary. The Laser Doppler Velocimeter (LDV) is an established method for measuring local flow velocities. For exact estimation of the flow rate, the flow profile in the shear layer is of importance. For standard LDV the axial resolution and therefore the number of measurement points in the shear layer is defined by the length of the measurement volume. A decrease of this length is accompanied by a larger fringe distance variation along the measurement axis which results in a rise of the measurement uncertainty for the flow velocity (uncertainty relation between spatial resolution and velocity uncertainty). As a unique advantage, the laser Doppler profile sensor (LDV-PS) overcomes this problem by using two fan-like fringe systems to obtain the position of the measured particles along the measurement axis and therefore achieve a high spatial resolution while it still offers a low velocity uncertainty. With this technique, the flow rate can be estimated with one order of magnitude lower uncertainty, down to 0:05% statistical uncertainty.1 And flow profiles especially in film flows can be measured more accurately. The problem for this technique is, in contrast to laboratory setups where the system is quite stable, that for industrial applications the sensor needs a reliable and robust traceability to the SI units, meter and second. Small deviations in the calibration can, because of the highly position depending calibration function, cause large systematic errors in the measurement result. Therefore, a simple, stable and accurate tool is needed, that can easily be used in industrial surroundings to check or recalibrate the sensor. In this work, different calibration methods are presented and their influences to the

  6. FSD-HSO Optimization Algorithm for Closed Fringes Interferogram Demodulation

    Directory of Open Access Journals (Sweden)

    Ulises H. Rodriguez-Marmolejo

    2016-01-01

    Full Text Available Due to the physical nature of the interference phenomenon, extracting the phase of an interferogram is a known sinusoidal modulation problem. In order to solve this problem, a new hybrid mathematical optimization model for phase extraction is established. The combination of frequency guide sequential demodulation and harmony search optimization algorithms is used for demodulating closed fringes patterns in order to find the phase of interferogram applications. The proposed algorithm is tested in four sets of different synthetic interferograms, finding a range of average relative error in phase reconstructions of 0.14–0.39 rad. For reference, experimental results are compared with the genetic algorithm optimization technique, obtaining a reduction in the error up to 0.1448 rad. Finally, the proposed algorithm is compared with a very known demodulation algorithm, using a real interferogram, obtaining a relative error of 1.561 rad. Results are shown in patterns with complex fringes distribution.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. Holographic images reconstructed from GMR-based fringe pattern

    Directory of Open Access Journals (Sweden)

    Kikuchi Hiroshi

    2013-01-01

    Full Text Available We have developed a magneto-optical spatial light modulator (MOSLM using giant magneto-resistance (GMR structures for realizing a holographic three-dimensional (3D display. For practical applications, reconstructed image of hologram consisting of GMR structures should be investigated in order to study the feasibility of the MOSLM. In this study, we fabricated a hologram with GMR based fringe-pattern and demonstrated a reconstructed image. A fringe-pattern convolving a crossshaped image was calculated by a conventional binary computer generated hologram (CGH technique. The CGH-pattern has 2,048 × 2,048 with 5 μm pixel pitch. The GMR stack consists of a Tb-Fe-Co/CoFe pinned layer, a Ag spacer, a Gd-Fe free layer for light modulation, and a Ru capping layer, was deposited by dc-magnetron sputtering. The GMR hologram was formed using photo-lithography and Krion milling processes, followed by the deposition of a Tb-Fe-Co reference layer with large coercivity and the same Kerr-rotation angle compared to the free layer, and a lift-off process. The reconstructed image of the ON-state was clearly observed and successfully distinguished from the OFF-state by switching the magnetization direction of the free-layer with an external magnetic field. These results indicate the possibility of realizing a holographic 3D display by the MOSLM using the GMR structures.

  10. Large-scale full-field metrology using projected fringes: some challenges and solutions

    Science.gov (United States)

    Huntley, Jonathan M.; Ogundana, Tokunbo; Burguete, Richard L.; Coggrave, C. Russell

    2007-06-01

    The application of optical techniques to the measurement of shape and deformation of structures in the aerospace industry poses unique challenges resulting from the large length scales involved, which are typically in the 1-10 m range. For example, the relative immobility of large samples requires a network of sensors to be linked into a common global coordinate system; traceable calibration requires the development of new types of calibration artefact; and traditional interferometric techniques for displacement field mapping are frequently too sensitive to observe the physical effect of interest. We describe a system designed to address some of these problems based on the projected fringe technique combined with temporal phase unwrapping. Multiple cameras and projectors are linked into a common coordinate system using calibration concepts borrowed from the photogrammetry field. Traceable calibration is achieved through the use of reference spheres separated by a bar of known length. Traditional two-dimensional image processing techniques for recognizing circles (Hough transforms) have been extended to the automatic detection of spheres within the measured 3-D point clouds. Bundle adjustment software has been developed to refine the camera and projector calibration parameters as well as the rigid body translation and rotation coordinates defining the poses of the calibration artefact. An overview of all these aspects of the developed techniques is given in the paper. Typical results from a compression test on a large scale aluminium structure, performed on-site at Airbus UK using the developed system, are also presented.

  11. Sensor placement algorithm development to maximize the efficiency of acid gas removal unit for integrated gasification combined cycle (IGCC) power plant with CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Paul, P.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    Future integrated gasification combined cycle (IGCC) power plants with CO{sub 2} capture will face stricter operational and environmental constraints. Accurate values of relevant states/outputs/disturbances are needed to satisfy these constraints and to maximize the operational efficiency. Unfortunately, a number of these process variables cannot be measured while a number of them can be measured, but have low precision, reliability, or signal-to-noise ratio. In this work, a sensor placement (SP) algorithm is developed for optimal selection of sensor location, number, and type that can maximize the plant efficiency and result in a desired precision of the relevant measured/unmeasured states. In this work, an SP algorithm is developed for an selective, dual-stage Selexol-based acid gas removal (AGR) unit for an IGCC plant with pre-combustion CO{sub 2} capture. A comprehensive nonlinear dynamic model of the AGR unit is developed in Aspen Plus Dynamics® (APD) and used to generate a linear state-space model that is used in the SP algorithm. The SP algorithm is developed with the assumption that an optimal Kalman filter will be implemented in the plant for state and disturbance estimation. The algorithm is developed assuming steady-state Kalman filtering and steady-state operation of the plant. The control system is considered to operate based on the estimated states and thereby, captures the effects of the SP algorithm on the overall plant efficiency. The optimization problem is solved by Genetic Algorithm (GA) considering both linear and nonlinear equality and inequality constraints. Due to the very large number of candidate sets available for sensor placement and because of the long time that it takes to solve the constrained optimization problem that includes more than 1000 states, solution of this problem is computationally expensive. For reducing the computation time, parallel computing is performed using the Distributed Computing Server (DCS®) and the Parallel

  12. Sensor placement algorithm development to maximize the efficiency of acid gas removal unit for integrated gasifiction combined sycle (IGCC) power plant with CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Paul, P.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    Future integrated gasification combined cycle (IGCC) power plants with CO{sub 2} capture will face stricter operational and environmental constraints. Accurate values of relevant states/outputs/disturbances are needed to satisfy these constraints and to maximize the operational efficiency. Unfortunately, a number of these process variables cannot be measured while a number of them can be measured, but have low precision, reliability, or signal-to-noise ratio. In this work, a sensor placement (SP) algorithm is developed for optimal selection of sensor location, number, and type that can maximize the plant efficiency and result in a desired precision of the relevant measured/unmeasured states. In this work, an SP algorithm is developed for an selective, dual-stage Selexol-based acid gas removal (AGR) unit for an IGCC plant with pre-combustion CO{sub 2} capture. A comprehensive nonlinear dynamic model of the AGR unit is developed in Aspen Plus Dynamics® (APD) and used to generate a linear state-space model that is used in the SP algorithm. The SP algorithm is developed with the assumption that an optimal Kalman filter will be implemented in the plant for state and disturbance estimation. The algorithm is developed assuming steady-state Kalman filtering and steady-state operation of the plant. The control system is considered to operate based on the estimated states and thereby, captures the effects of the SP algorithm on the overall plant efficiency. The optimization problem is solved by Genetic Algorithm (GA) considering both linear and nonlinear equality and inequality constraints. Due to the very large number of candidate sets available for sensor placement and because of the long time that it takes to solve the constrained optimization problem that includes more than 1000 states, solution of this problem is computationally expensive. For reducing the computation time, parallel computing is performed using the Distributed Computing Server (DCS®) and the Parallel

  13. Qualitative analysis of land use change pressures, conditions and drivers in rural-urban fringes: A case of Nairobi rural-urban fringe, Kenya

    OpenAIRE

    Aggrey Daniel Maina Thuo

    2013-01-01

    This paper is grounded on the truism that the planet's future is urban. However, urban growth process is bringing rapid economic, social and physical changes. These changes are bringing rapid transformations in areas concerned, especially on land uses in rural-urban fringes. While this is happening, the pressures and drivers are not well documented and understood, particularly so for rural-urban fringes in developing countries such as Kenya.This paper is based on a qualitative research approa...

  14. 26 CFR 1.132-5T - Working condition fringe-1985 through 1988 (temporary).

    Science.gov (United States)

    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...

  15. Explanations for Long-Distance Counter-Urban Migration into Fringe Areas in Denmark

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    2009-01-01

    infl uence on migration to fringe areas. The study shows that a considerable share of movers to the fringe areas in Denmark can be characterised as income-transfer mover. They are people without employment moving to get lower housing costs. But there are also groups of people moving to employment...

  16. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Science.gov (United States)

    2010-07-01

    ... of the applicable fringe benefit determination is entitled to holiday pay or another day off with pay... in the fringe benefit determination are the reference points for determining whether an employee is... benefit determination listing New Year's Day as a named holiday, and if New Year's Day were...

  17. Decorrelation and fringe visibility: On the limiting behavior of varous electronic speckle pattern correlation interferometers

    DEFF Research Database (Denmark)

    Owner-Petersen, Mette

    1996-01-01

    I discuss the behavior of fringe formation in image-plane electronic speckle-pattern correlation interferometers as the limit of total decorrelation is approached. The interferometers are supposed to operate in the difference mode. The effect of decorrelation will be a decrease in fringe visibility...

  18. Multi-Sensor Architectures

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar; Ahmed, Zaki; Khan, M. Z.

    2012-01-01

    The use of multiple sensors typically requires the fusion of data from different type of sensors. The combined use of such a data has the potential to give an efficient, high quality and reliable estimation. Input data from different sensors allows the introduction of target attributes (target type......, size) into the association logic. This requires a more general association logic, in which both the physical position parameters and the target attributes can be used simultaneously. Although, the data fusion from a number of sensors could provide better and reliable estimation but abundance...... processing units for same type of multiple sensors, typically radar in our case....

  19. Analysis of the localization of Michelson interferometer fringes using Fourier optics and temporal coherence

    Energy Technology Data Exchange (ETDEWEB)

    Narayanamurthy, C S [Department of Physics, Indian Institute of Space Science and Technology (IIST), Department of Space (Govt of India), ATF Campus, VSSC, ISRO - PO, Thiruvananthapuram 695 022 (India)], E-mail: naamu.s@gmail.com

    2009-01-15

    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 have never been analysed seriously in any book. Because Michelson's interferometer is one of the important and fundamental optical experiments taught at both undergraduate and graduate levels, it would be appropriate to explain the localization of these fringes. In this paper, we analyse the localization of Michelson interferometer fringes using Fourier optics and temporal coherence, and show that they never localize at any plane even at infinity.

  20. Skeleton extraction and phase interpolation for single ESPI fringe pattern based on the partial differential equations.

    Science.gov (United States)

    Zhang, Fang; Wang, Danyu; Xiao, Zhitao; Geng, Lei; Wu, Jun; Xu, Zhenbei; Sun, Jiao; Wang, Jinjiang; Xi, Jiangtao

    2015-11-16

    A novel phase extraction method for single electronic speckle pattern interferometry (ESPI) fringes is proposed. The partial differential equations (PDEs) are used to extract the skeletons of the gray-scale fringe and to interpolate the whole-field phase values based on skeleton map. Firstly, the gradient vector field (GVF) of the initial fringe is adjusted by an anisotropic PDE. Secondly, the skeletons of the fringe are extracted combining the divergence property of the adjusted GVF. After assigning skeleton orders, the whole-field phase information is interpolated by the heat conduction equation. The validity of the proposed method is verified by computer-simulated and experimentally obtained poor-quality ESPI fringe patterns.

  1. The effect of wavefront corrugations on fringe motion in an astronomical interferometer with spatial filters

    CERN Document Server

    Tubbs, R

    2005-01-01

    Numerical simulations of atmospheric turbulence and AO wavefront correction are performed to investigate the timescale for fringe motion in optical interferometers with spatial filters. These simulations focus especially on partial AO correction, where only a finite number of Zernike modes are compensated. The fringe motion is found to depend strongly on both the aperture diameter and the level of AO correction used. In all of the simulations the coherence timescale for interference fringes is found to decrease dramatically when the Strehl ratio provided by the AO correction is <~30%. For AO systems which give perfect compensation of a limited number of Zernike modes, the aperture size which gives the optimum signal for fringe phase tracking is calculated. For AO systems which provide noisy compensation of Zernike modes (but are perfectly piston-neutral), the noise properties of the AO system determine the coherence timescale of the fringes when the Strehl ratio is <~30%.

  2. Fiber optic liquid refractive index sensor

    Science.gov (United States)

    Bhardwaj, Vanita; Gangwar, Rahul Kumar; Singh, Vinod Kumar

    2015-08-01

    In this present work we report fabrication of fiber optic liquid refractive index (RI) measurement sensor based on Michelson Interferometer method. This sensor was assembled by using graded index multimode (MM) fiber with core diameter 50 µm and the cladding of fiber was removed by simple chemical method. To perform this experiment a 2×2 3dB coupler is used. The fiber ends are then immersed in solvent and solution to provide reference and refractive index measurements, respectively. This method was successfully used to measure refractive index of Sodium Chloride (NaCl)-Water solution at different concentrations. The fringe contrast sensitivity of device is 92.90 dB/RIU measured in the RI range from 1.34 to 1.42 which is better than Mach-Zehnder Interferometer sensor [1] and Fabry perot based sensor [2]. The fabrication of sensor is simple, low cost and highly sensitive.

  3. RACIAL DIFFERENCES IN AVAILABILITY OF FRINGE BENEFITS AS AN EXPLANATION FOR THE UNEXPLAINED BLACKWHITE WAGE GAP FOR MALES IN US

    OpenAIRE

    Kristjan-Olari Leping

    2007-01-01

    The US black-white wage gap is an issue that has attracted thorough investigation, but so far the corresponding gap for fringe benefits has not received sufficient attention. Although ethnic differences in fringe benefits could affect wage differences, previous analysis of ethnic wage gaps in the vast majority of cases has not taken fringe benefits into account. In order to fill that gap in the existing literature, this article estimates the black-white gap for both wages and fringe benefits ...

  4. RACIAL DIFFERENCES IN AVAILABILITY OF FRINGE BENEFITS AS AN EXPLANATION FOR THE UNEXPLAINED BLACKWHITE WAGE GAP FOR MALES IN US

    OpenAIRE

    Kristjan-Olari Leping

    2007-01-01

    The US black-white wage gap is an issue that has attracted thorough investigation, but so far the corresponding gap for fringe benefits has not received sufficient attention. Although ethnic differences in fringe benefits could affect wage differences, previous analysis of ethnic wage gaps in the vast majority of cases has not taken fringe benefits into account. In order to fill that gap in the existing literature, this article estimates the black-white gap for both wages and fringe benefits ...

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

    Science.gov (United States)

    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. Accurate Calculation of Fringe Fields in the LHC Main Dipoles

    CERN Document Server

    Kurz, S; Siegel, N

    2000-01-01

    The ROXIE program developed at CERN for the design and optimization of the superconducting LHC magnets has been recently extended in a collaboration with the University of Stuttgart, Germany, with a field computation method based on the coupling between the boundary element (BEM) and the finite element (FEM) technique. This avoids the meshing of the coils and the air regions, and avoids the artificial far field boundary conditions. The method is therefore specially suited for the accurate calculation of fields in the superconducting magnets in which the field is dominated by the coil. We will present the fringe field calculations in both 2d and 3d geometries to evaluate the effect of connections and the cryostat on the field quality and the flux density to which auxiliary bus-bars are exposed.

  7. The LINC-NIRVANA fringe and flexure tracker: laboratory tests

    Science.gov (United States)

    Tremou, Evangelia; Eckart, Andreas; Horrobin, Matthew; Lindhorst, Bettina; Moser, Lydia; Rost, Steffen; Smajic, Semir; Straubmeier, Christian; Wank, Imke; Zuther, Jens; Bertram, Thomas

    2010-07-01

    LINC-NIRVANA is the NIR homothetic imaging camera for the Large Binocular Telescope (LBT). In close cooperation with the Adaptive Optics systems of LINC-NIRVANA the Fringe and Flexure Tracking System (FFTS) is a fundamental component to ensure a complete and time-stable wavefront correction at the position of the science detector in order to allow for long integration times at interferometric angular resolutions. In this contribution, we present the design and the realization of the ongoing FFTS laboratory tests, taking into account the system requirements. We have to sample the large Field of View and to follow the reference source during science observations to an accuracy of less than 2 microns. In particular, important tests such as cooling tests of cryogenic components and tip - tilt test (the repeatability and the precision under the different inclinations) are presented. The system parameters such as internal flexure and precision are discussed.

  8. Leaf cuticle topography retrieved by using fringe projection

    Science.gov (United States)

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

    2012-02-01

    The combination (often referred to as phase-stepping profilometry, PSP) of the fringe projection technique and the phase-stepping method allowed us to retrieve topographic maps of cuticles isolated from the abaxial surface of leaves; these were in turn sampled from an apple tree ( Malus domestica) of the variety Golden Delicious. The topographic maps enabled us to assess the natural features on the illuminated surface and also to detect the whole-field spatial variations in the thickness of the cuticle. Most of our attention was paid to retrieve the highly-resolved elevation information from the cuticle surface, which included the trace (in the order of tens of micrometers) left by ribs and veins. We expect that the PSP application for retrieving the cuticle topography will facilitate further studies on the dispersion and coverage of state-of-the-art agrochemical compounds meant to improve the defending properties of the cuticle. Methodological details are provided below.

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

    Science.gov (United States)

    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.

  10. Fringe Tracker for the VLTI Spectro-Imager

    CERN Document Server

    Corcione, L; Busher, D F; Gai, M; Ligori, S; Loreggia, D; Masssone, G; Young, J S

    2008-01-01

    The implementation of the simultaneous combination of several telescopes (from four to eight) available at Very Large Telescope Interferometer (VLTI) will allow the new generation interferometric instrumentation to achieve interferometric image synthesis with unprecedented resolution and efficiency. The VLTI Spectro Imager (VSI) is the proposed second-generation near-infrared multi-beam instrument for the Very Large Telescope Interferometer, featuring three band operations (J, H and K), high angular resolutions (down to 1.1 milliarcsecond) and high spectral resolutions. VSI will be equipped with its own internal Fringe Tracker (FT), which will measure and compensate the atmospheric perturbations to the relative beam phase, and in turn will provide stable and prolonged observing conditions down to the magnitude K=13 for the scientific combiner. In its baseline configuration, VSI FT is designed to implement, from the very start, the minimum redundancy combination in a nearest neighbor scheme of six telescopes o...

  11. Measuring the Sizes of Stars: Fringe Benefits of Interferometry

    Indian Academy of Sciences (India)

    Rajaram Nityananda

    2017-07-01

    Stars, other than the Sun, appear to our unaided eyes aspoints of light. Large telescopes show an image whose sizeis dictated by refractive index irregularities in the Earth’s atmosphere.The size of this blurring is much greater than thatof the star, and hence it is difficult to measure the stellar size.Fizeau showed how one might overcome this limitation usingthe two-slit interference technique. It was Michelson whocarried out this programme and made the first direct measurementof the giant star Betelguse in the constellation ofOrion. His value for the angular diameter, 47 milliarcsecondsor 2.6×10−7 radians, was completely confirmed by laterwork following his methods. The key concept introduced was ‘fringe visibility’, which turned out to be very fruitful in thelater development of optics as well as astronomy.

  12. 3D shape measurement with phase correlation based fringe projection

    Science.gov (United States)

    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.

  13. Phenological Classification of the United States: A Geographic Framework for Extending Multi-Sensor Time-Series Data

    Directory of Open Access Journals (Sweden)

    Willem J. D. van Leeuwen

    2010-02-01

    Full Text Available This study introduces a new geographic framework, phenological classification, for the conterminous United States based on Moderate Resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI time-series data and a digital elevation model. The resulting pheno-class map is comprised of 40 pheno-classes, each having unique phenological and topographic characteristics. Cross-comparison of the pheno-classes with the 2001 National Land Cover Database indicates that the new map contains additional phenological and climate information. The pheno-class framework may be a suitable basis for the development of an Advanced Very High Resolution Radiometer (AVHRR-MODIS NDVI translation algorithm and for various biogeographic studies.

  14. Automated Sensor Tuning for Seismic Event Detection at a Carbon Capture, Utilization, and Storage Site, Farnsworth Unit, Ochiltree County, Texas

    Science.gov (United States)

    Ziegler, A.; Balch, R. S.; Knox, H. A.; Van Wijk, J. W.; Draelos, T.; Peterson, M. G.

    2016-12-01

    We present results (e.g. seismic detections and STA/LTA detection parameters) from a continuous downhole seismic array in the Farnsworth Field, an oil field in Northern Texas that hosts an ongoing carbon capture, utilization, and storage project. Specifically, we evaluate data from a passive vertical monitoring array consisting of 16 levels of 3-component 15Hz geophones installed in the field and continuously recording since January 2014. This detection database is directly compared to ancillary data (i.e. wellbore pressure) to determine if there is any relationship between seismic observables and CO2 injection and pressure maintenance in the field. Of particular interest is detection of relatively low-amplitude signals constituting long-period long-duration (LPLD) events that may be associated with slow shear-slip analogous to low frequency tectonic tremor. While this category of seismic event provides great insight into dynamic behavior of the pressurized subsurface, it is inherently difficult to detect. To automatically detect seismic events using effective data processing parameters, an automated sensor tuning (AST) algorithm developed by Sandia National Laboratories is being utilized. AST exploits ideas from neuro-dynamic programming (reinforcement learning) to automatically self-tune and determine optimal detection parameter settings. AST adapts in near real-time to changing conditions and automatically self-tune a signal detector to identify (detect) only signals from events of interest, leading to a reduction in the number of missed legitimate event detections and the number of false event detections. Funding for this project is provided by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) through the Southwest Regional Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591. Additional support has been provided by site operator Chaparral Energy, L.L.C. and Schlumberger Carbon Services. Sandia National

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Steerable Capacitive Proximity Sensor

    Science.gov (United States)

    Jenstrom, Del T.; Mcconnell, Robert L.

    1994-01-01

    Steerable capacitive proximity sensor of "capaciflector" type based partly on sensing units described in GSC-13377 and GSC-13475. Position of maximum sensitivity adjusted without moving sensor. Voltage of each driven shield adjusted separately to concentrate sensing electric field more toward one side or other.

  18. Vision-based measurement system for structural vibration monitoring using non-projection quasi-interferogram fringe density enhanced by spectrum correction method

    Science.gov (United States)

    Zhong, Jianfeng; Zhong, Shuncong; Zhang, Qiukun; Zhuang, Yizhou; Lu, Huancai; Fu, Xinbin

    2017-01-01

    A non-projection fringe vision measurement system suitable for vibration monitoring was proposed by using the concept of a 2D optical coherence vibration tomography (2D-OCVT) technique. An artificial quasi-interferogram fringe pattern (QIFP), similar to the interferogram of the 2D-OCVT system, was pasted onto the surface of a vibrating structure as a sensor. Image sequences of the QIFP were captured by a high-speed CMOS camera that worked as a detector. It was possible to obtain both the in-plane and out-of-plane vibration simultaneously. The in-plane vibration was obtained by tracking the center of the imaged QIFP using an image cross-correlation method, whilst the out-of-plane vibration was obtained from the changes in period density of the imaged QIFP. The influence of the noise sources from the CMOS image sensor, together with the effect of the imaging distance, the period density of the QIFP and also the key parameters of the fringe density enhanced by the spectrum correction method on the accuracy of the displacement measurement, were investigated by numerical simulations and experiments. Compared with the results from a conventional accelerometer-based measurement system, the proposed method was demonstrated to be an effective and accurate technique for measuring structural vibration without introducing any extra mass from the accelerometer. The significant advantages of this method include its simple installation and real-time dynamic response measurement capability, making the measurement system ideal for the low- and high-frequency vibration monitoring of engineering structures.

  19. Measurement, analysis and modification of the fifth-order fringe field components of magnetic quadrupole lenses

    Energy Technology Data Exchange (ETDEWEB)

    Moloney, G.R.; Jamieson, D.N.; Legge, G.J.F. (School of Physics, Univ. of Melbourne, Parkville (Australia))

    1991-03-01

    Extensive, quantitative measurements of magnetic quadrupole lens fringe fields have been conducted. The fringe field region of magnetic quadrupole lenses has been shown to contain significant contamination by higher-order multipole fields. These multipole components will contribute to the aberration coefficients of the lens. One of the largest components is the duodecapole component, which contributes to the fifth-order geometric aberrations of the lens. The measured multipole profiles in the fringe field region of the Melbourne quadrupoles are presented. We also present the results of an investigation into the effect of modifying the quadrupole pole tip profile at the pole ends. (orig.).

  20. Denoising in electronic speckle pattern interferometry fringes by the filtering method based on partial differential equations

    Science.gov (United States)

    Tang, Chen; Zhang, Fang; Yan, Haiqing; Chen, Zhanqing

    2006-04-01

    Denoising in electronic speckle pattern interferometry fringes is the key problem in electronic speckle pattern interferometry. We present the new filtering method based on partial differential equations (called PDE filtering method) to electronic speckle pattern interferometry fringes. The PDE filtering method transforms the image processing to solving the partial differential equations. We test the proposed method on experimentally obtained electronic speckle pattern interferometry fringes, and compare with traditional mean filtering and low-pass Fourier filtering methods. The experimental results show that the technique is capable of effectively removing noise. The PDE filtering method is flexible and has fast computational speed and stable results.

  1. Removal of Spectro-Polarimetric Fringes by 2D Pattern Recognition

    CERN Document Server

    Casini, R; Schad, T A

    2012-01-01

    We present a pattern-recognition based approach to the problem of removal of polarized fringes from spectro-polarimetric data. We demonstrate that 2D 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Casini, R.; Judge, P. G. [High Altitude Observatory, NCAR P.O. Box 3000, Boulder, CO 80307-3000 (United States); Schad, T. A. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    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.

  3. Evaluation of absolute phase for 3D profile measurement using fringe projection

    Institute of Scientific and Technical Information of China (English)

    Mengtao Huang; Zhuangde Jiang; Bing Li; Suping Fang

    2006-01-01

    A new method of absolute phase evaluation for three-dimensional (3D) profile measurement using fringe projection is presented, which combines the gray code and the phase shift technique. Two kinds of fringe patterns are projected onto the object surface respectively, one is sinusoidal intensity distribution used for phase demodulation and the other is gray code fringe pattern for unwrapping. These images are acquired by camera and stored into computer. The absolute phase is obtained by analyzing these images. The validity of this method is verified experimentally. The method is superior to other phase unwrapping methods.

  4. Reduction of interference fringes in absorption imaging of cold atom cloud using eigenface method

    Institute of Scientific and Technical Information of China (English)

    Xiaolin Li; Min Ke; Bo Yan; Yuzhu Wang

    2007-01-01

    Eigenface method used in face recognition is introduced to reduce the pattern of interference fringes appearing in the absorption image of cold rubidium atom cloud trapped by an atom chip. The standard method for processing the absorption image is proposed, and the origin of the interference fringes is analyzed. Compared with the standard processing method which uses only one reference image, we take advantage of fifty reference images and reconstruct a new reference image which is more similar to the absorption image than all of the fifty original reference images. Then obvious reduction of interference fringes can be obtained.

  5. Surface height retrieval based on fringe shifting of color-encoded structured light pattern.

    Science.gov (United States)

    Chen, Hui Jun; Zhang, Jue; Fang, Jing

    2008-08-15

    A new method of fringe shifting for color structured pattern projection is presented for three-dimensional (3D) surface height measurement. Temporal encoding of color stripes is combined with locally spatial shifting of multiple fringes to realize image acquisition with a small number of pattern projections. Object topography is retrieved with high resolution by decoding the code word of each fringe with the help of the redundant information provided by the shifting patterns and the encoding patterns in their temporal and spatial neighborhoods. An application to evaluate the shape of a buckled tube demonstrates the effectiveness of the method.

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

    Science.gov (United States)

    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.

  7. Fringe Capacitance Correction for a Coaxial Soil Cell

    Directory of Open Access Journals (Sweden)

    John D. Wanjura

    2011-01-01

    Full Text Available 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

  8. Cambrian to Lower Ordovician complexes of the Kokchetav Massif and its fringing (Northern Kazakhstan): Structure, age, and tectonic settings

    Science.gov (United States)

    Degtyarev, K. E.; Tolmacheva, T. Yu.; Tretyakov, A. A.; Kotov, A. B.; Shatagin, K. N.

    2016-01-01

    A comprehensive study of the Lower Palaeozoic complexes of the Kokchetav Massif and its fringing has been carried out. It has allowed for the first time to discover and investigate in detail the stratified and intrusive complexes of the Cambrian-Early Ordovician. Fossil findings and isotope geochronology permitted the determination of their ages. The tectonic position and internal structures of those complexes have also been defined and their chemical features have been analyzed as well. The obtained data allowed us to put forward a model of the geodynamic evolution of Northern Kazakhstan in the Late Ediacaran-Earliest Ordovician. The accumulation of the oldest Ediacaran to Earliest Cambrian siliciclastics and carbonates confined to the Kokchetav Massif and its fringing occurred in a shallow shelf environment prior to its collision with the Neoproterozoic Daut island arc: complexes of the latter have been found in the northeast of the studied area. The Early Cambrian subduction of the Kokchetav Massif under the Daut island arc, their following collision and exhumation of HP complexes led to the formation of rugged ground topography, promoting deposition of siliceous-clastic and coarse clastic units during the Middle to early Late Cambrian. Those sediments were mainly sourced from eroded metamorphic complexes of the Kokchetav Massif basement. At the end of the Late Cambrian to the Early Ordovician within the boundaries of the massif with the Precambrian crust, volcanogenic and volcano-sedimentary units along with gabbros and granites with intraplate affinities were formed. Simultaneously in the surrounding zones, which represent relics of basins with oceanic crust, N-MORB- and E-MORB-type ophiolites were developed. These complexes originated under extensional settings occurred in the majority of the Caledonides of Kazakhstan and Northern Tian Shan. In the Early Floian Stage (Early Ordovician) older heterogeneous complexes were overlain by relatively monotonous

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

    Science.gov (United States)

    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.

  10. 3D shape measurement of optical free-form surface based on fringe projection

    Science.gov (United States)

    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.

  11. Modeling of the fringe shift in multiple beam interference for glass fibers

    Indian Academy of Sciences (India)

    A M Hamed

    2008-04-01

    A quadratic model is suggested to describe the fringe shift occurred due to the phase variations of uncladded glass fiber introduced between the two plates of the liquid wedge interferometer. The fringe shift of the phase object is represented in the harmonic term which appears in the denominator of the Airy distribution formula of Fabry-Perot's interferometer. A computer program is written to plot the computed fringe shifts of the described model. An experiment is conducted using liquid wedge interferometer where the fiber of a nearly quadratic thickness variation is introduced between the two plates of the interferometer. The obtained fringe shift shows a good agreement with the proposed quadratic model. Also, it is compared with the previous theoretical shift based on ray optics of semi-circular shape.

  12. Basic Science of the Fundamentals and Dynamics of Social-Fringe Group Formation and Sustainment

    Science.gov (United States)

    2012-08-01

    Counseling Psychology Ph ilosophy (3) Mathemancs Human Fact ors (2) Civil Engineering Secondary Political Science (2) Religious St udies ... Mexico , S. Korea). Study of Social Fringe Group Formation Processes: Crystallization vs. Transformation This proposes to use case study analysis to

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

    Science.gov (United States)

    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.

  14. Noise reduction in electronic speckle pattern interferometry fringes by fourth-order partial differential equations

    Science.gov (United States)

    Lv, Wei; Tang, Chen; Wang, Wenping

    2007-01-01

    Noise reduction is one of the largest problems and biggest difficulties involved in electronic speckle pattern interferometry (ESPI). Although the second-order PDEs denoising method is a useful tool of noise reduction for the ESPI fringe patterns, its main drawback is that the second-order PDE model does not remove impulse noise, a 3×3 mean window filter is generally needed to improve the fringes. For overcome this main drawback, in this paper we apply the fourth-order PDE denoising model to the computer-simulated and experimentally obtained ESPI fringe, respectively. In both tests, the fourth-order PDE denoising model clearly outperforms the second-order PDE denoising model. Experimental results have confirmed that the fourth-order PDE denoising model is capable of removing noise in ESPI fringe images effectively.

  15. Change Phenomena of Spatial Physical in the Dynamics of Development in Urban Fringe Area

    National Research Council Canada - National Science Library

    Batara Surya

    2016-01-01

      The study aims at analyzing change of spatial physical, spatial articulation, spatial structure, social and agglomeration and deagglomeration of function in the dynamics of development in the fringe...

  16. Measurement of thickness profiles of glass plates by analyzing Haidinger fringes.

    Science.gov (United States)

    Park, Ju Eun; Kim, Jiung; Cha, Myoungsik

    2017-03-01

    We report what we believe is a novel method for measuring the thickness profiles of plane parallel plates by analyzing their Haidinger fringes. When an extended monochromatic source is viewed through a ∼1-mm-thick plate, concentric transmission-type Haidinger fringes can easily be observed. Small variations in the plate thickness result in changes in the radii of the ring fringes. In this study, we scanned 20-mm-diameter fused silica and BK7 plates while tracing a specific ring in each fringe pattern to measure the thickness profiles of the plates, achieving an uncertainty of 2 nm in the measurements of the thickness differences between two locations on each plate.

  17. High-quality binary fringe generation via joint optimization on intensity and phase

    Science.gov (United States)

    Xiao, Yi; Li, Youfu

    2017-10-01

    There have been active studies on optimized dithering techniques to improve 3D shape measurement quality with defocused projectors. These techniques optimize the fringe quality in either phase domain or intensity domain according to their objective functions. Phase based optimization is direct and effective, but is sensitive to projector defocus levels. Intensity based optimization is robust to projector defocus levels, but it does not fully improve the phase quality. This paper presents a joint optimization technique to combine the merits of both the intensity and phase based optimization, which includes a pre-intensity optimization and a further optimization based on the synthesized error function. Then this technique is implemented in two frameworks, the whole-fringe optimization and the best-patch optimization, to generate binary fringe patterns. Both simulations and experiments show that the proposed technique can generate binary fringe patterns with high phase quality and robustness to projector defocus levels.

  18. Lens distortion elimination for improving measurement accuracy of fringe projection profilometry

    Science.gov (United States)

    Li, Kai; Bu, Jingjie; Zhang, Dongsheng

    2016-10-01

    Fringe projection profilometry (FPP) is a powerful method for three-dimensional (3D) shape measurement. However, the measurement accuracy of the existing FPP is often hindered by the distortion of the lens used in FPP. In this paper, a simple and efficient method is presented to overcome this problem. First, the FPP system is calibrated as a stereovision system. Then, the camera lens distortion is eliminated by correcting the captured images. For the projector lens distortion, distorted fringe patterns are generated according to the lens distortion model. With these distorted fringe patterns, the projector can project undistorted fringe patterns, which means that the projector lens distortion is eliminated. Experimental results show that the proposed method can successfully eliminate the lens distortions of FPP and therefore improves its measurement accuracy.

  19. Sediment transport and carbon sequestration characteristics along mangrove fringed coasts

    Institute of Scientific and Technical Information of China (English)

    TU Qiang; YANG Shengyun; ZHOU Qiulin; YANG Juan

    2015-01-01

    Mangroves play an important role in sequestering carbon and trapping sediments. However, the effectiveness of such functions is unclear due to the restriction of knowledge on the sedimentation process across the vegetation boun-daries. To detect the effects of mangrove forests on sediment transportation and organic carbon sequestration, the granulometric and organic carbon characteristics of mangrove sediments were investigated from three vegetation zones of four typical mangrove habitats on the Leizhou Peninsula coast. Based on our results, sediment transport was often“environmentally sensitive”to the vegetation friction. A transition of the sediment transport mode from the mudflat zone to the interior/fringe zone was often detected from the cumulative frequency curve. The vegetation cover also assists the trapping of material, resulting in a significantly higher concentration of organic carbon in the interior surface sediments. However, the graphic parameters of core sediments reflected a highly temporal variability due to the sedimentation process at different locations. The sediment texture ranges widely from sand to mud, altho-ugh the sedimentary environments are restricted within the same energy level along the fluvial-marine transition zone. Based on the PCA results, the large variation was mainly attributed to either the mean grain size features or the organic carbon features. A high correlation between the depth andδ13C value also indicated an increasing storage of mangrove-derived organic carbon with time.

  20. 3D Alignment of nanowriters using fringe capacitance

    Science.gov (United States)

    Lally, Richard; Stark, Thomas; Reeves, Jeremy; Barrett, Lawrence; Bishop, David

    With the introduction of atomic calligraphy, high resolution nanoscale structures can be fabricated rapidly over a large surface area. This reliable, chemically stable and cost effective nanoscale writing method can be applied to a number of interesting applications. One specific application of this writing approach is to fabricate metamaterials, a process that requires precise alignment of the MEMS and substrate. Here we present a MEMS based solution coupling the well-studied comb drive capacitance effects with the less predictable close order fringe effects. The combined capacitance allows for precise measurements in the nanometer range. Using two sets of orthogonal static MEMS comb drives, the capacitance is used to discern the x, y, and z spatial displacement from the substrate. The unique SOI wafer is prepared creating a periodic array of silicon pillars. Placement of additional MEMS comb drives at the MEMS device edges will allow stage corrections for tip, tilt and rotational alignment thereby reducing the effects generated by variations in wafer thickness and surface smoothness. This work is funded by the DARPA A2P Program.

  1. Single frame profilometry with rapid phase demodulation on colour-coded fringes

    Science.gov (United States)

    Yee, Cong Kai; Yen, Kin Sam

    2017-08-01

    Digital fringe profilometry is a non-contact surface profiling technique with huge potential at real-time dynamic whole-field measurement. However, this technique is usually bottlenecked at the phase demodulation and unwrapping during fringe analysis. This paper proposes a single frame profilometry system that used direct arccosine function demodulation on colour-coded sinusoidal fringes to simplify the fringe analysis process. Since the range of arccosine function output is restricted from 0 to π, the intensity gradient was used along with arccosine function to demodulate the fringe intensity levels into wrapped phase map (0-2π). The projected fringes were coloured in red, green and blue according to the De Bruijn's sequence. The fringe order was identified directly from the colours of three consecutive fringes by matching to the De Bruijn's sequence to unwrap the wrapped phase map into continuous phase map. The phase differences between the continuous phase maps of reference plane and object surface were then obtained and related to the equipment setup position using trigonometry to rebuild the 3D model. The proposed method was tested experimentally by reconstructing three physical objects. Although the reconstructed surface contained phase errors due to gamma non-linearity, the geometrical shapes of the objects can be reconstructed with reasonable accuracy and consistency. The percentage deviations of dimensions in x, y and z-axis were 1.24%, -1.96% and -2.30% respectively. Meanwhile the uncertainties of dimensions in x, y and z-axis were ±0.15%, ±0.24% and ±1.07% respectively at 95% confidence level.

  2. The spatial distribution of green spaces in the urban fringe of Bangkok.

    OpenAIRE

    Hara, Yuji; Yokota, Shigehiro; Murakami, Akinobu; Takeuchi, Kazuhiko

    2004-01-01

    Urban green spaces with a wide variety of functions to ameliorate the urban environment have been decreased and fragmented in the urban fringe areas of Southeast Asian cities. In order to elaborate practical and efficient plans to conserve urban green spaces, and to monitor them continuously. From this view point, we inspected green cover, land-use and landholding, and their correlations in the urban fringe of Bangkok using GIS. As a result, the following four facts are revealed. First, urban...

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

    Science.gov (United States)

    2010-09-01

    spatial uncertainty on sound localization and to examine how such effects might be related to binaural detection and informational masking. 2 Methods...AFRL-RH-WP-TP-2012-0037 THE IMPACT OF MASKER FRINGE AND MASKER SPARIAL UNCERTAINTY ON SOUND LOCALIZATION Brian D. Simpson¹, Robert H...MASKER FRINGE AND MASKER SPARIAL UNCERTAINTY ON SOUND LOCALIZATION 5a. CONTRACT NUMBER IN-HOUSE 5b. GRANT NUMBER 5c

  4. Fringe trees, Crump-Mode-Jagers branching processes and $m$-ary search trees

    OpenAIRE

    Holmgren, Cecilia; Janson, Svante

    2016-01-01

    This survey studies asymptotics of random fringe trees and extended fringe trees in random trees that can be constructed as family trees of a Crump-Mode-Jagers branching process, stopped at a suitable time. This includes random recursive trees, preferential attachment trees, fragmentation trees, binary search trees and (more generally) $m$-ary search trees, as well as some other classes of random trees. We begin with general results, mainly due to Aldous (1991) and Jagers and Nerman (1984). T...

  5. Influence of the fringe field on moving of the charged particles in flat and cylindrical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Doskeyev, G.A.; Edenova, O.A. [Aktobe State University named after K. Zhubanov, Br. Zhubanov Street 263, 030000 Aktobe (Kazakhstan); Spivak-Lavrov, I.F., E-mail: spivakif@rambler.ru [Aktobe State University named after K. Zhubanov, Br. Zhubanov Street 263, 030000 Aktobe (Kazakhstan)

    2011-07-21

    This paper describes different analytic approaches to describe the fringe fields of flat and cylindrical capacitor structures. A method for the calculation of deflection of charged particles from the optical axis is developed. The behavior of a charged particle beam in a flat capacitor is approximated by using a sharp cut-off boundary for the field, which has the provision of taking fringe fields into account.

  6. On-Chip Method to Measure Mechanical Characteristics of a Single Cell by Using Moiré Fringe

    Directory of Open Access Journals (Sweden)

    Hirotaka Sugiura

    2015-06-01

    Full Text Available We propose a method to characterize the mechanical properties of cells using a robot-integrated microfluidic chip (robochip and microscopy. The microfluidic chip is designed to apply the specified deformations to a single detached cell using an on-chip actuator probe. The reaction force is simultaneously measured using an on-chip force sensor composed of a hollow folded beam and probe structure. In order to measure the cellular characteristics in further detail, a sub-pixel level of resolution of probe position is required. Therefore, we utilize the phase detection of moiré fringe. Using this method, the experimental resolution of the probe position reaches 42 nm. This is approximately ten times smaller than the optical wavelength, which is the limit of sharp imaging with a microscope. Calibration of the force sensor is also important in accurately measuring cellular reaction forces. We calibrated the spring constant from the frequency response, by the proposed sensing method of the probe position. As a representative of mechanical characteristics, we measured the elastic modulus of Madin-Darby Cannie Kidney (MDCK cells. In spite of the rigid spring constant, the resolution and sensitivity were twice that achieved in our previous study. Unique cellular characteristics can be elucidated by the improvements in sensing resolution and accuracy.

  7. Influence of Microwave Detuning on Ramsey Fringes of a Single Nitrogen Vacancy Center Spin in Diamond

    Institute of Scientific and Technical Information of China (English)

    HU Xin; LIU Gang-Qin; XU Zhang-Cheng; PAN Xin-Yu

    2012-01-01

    We investigate the Ramsey fringes of a single electron spin of the nitrogen-vacancy center in diamond with different microwave radiation frequency detunings.The fast Fourier transform demonstrates that the Ramsey fringes consist of three components caused by hyperfine interaction with 14N nuclear spin,and the Ramsey fringes cannot be well explained without the phase term of the three components,which has not been mentioned before.Each phase is determined by the microwave frequency detuning and the resonant Rabi frequency as well as the π/2 pulse.%We investigate the Ramsey fringes of a single electron spin of the nitrogen-vacancy center in diamond with different microwave radiation frequency detunings. The fast Fourier transform demonstrates that the Ramsey fringes consist of three components caused by hyperfine interaction with 14N nuclear spin, and the Ramsey fringes cannot be well explained without the phase term of the three components, which has not been mentioned before. Each phase is determined by the microwave frequency detuning and the resonant Rabi frequency as well as the π/2 pulse.

  8. Adaptive digital fringe projection technique for high dynamic range three-dimensional shape measurement.

    Science.gov (United States)

    Lin, Hui; Gao, Jian; Mei, Qing; He, Yunbo; Liu, Junxiu; Wang, Xingjin

    2016-04-04

    It is a challenge for any optical method to measure objects with a large range of reflectivity variation across the surface. Image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. This paper presents a new adaptive digital fringe projection technique which avoids image saturation and has a high signal to noise ratio (SNR) in the three-dimensional (3-D) shape measurement of objects that has a large range of reflectivity variation across the surface. Compared to previous high dynamic range 3-D scan methods using many exposures and fringe pattern projections, which consumes a lot of time, the proposed technique uses only two preliminary steps of fringe pattern projection and image capture to generate the adapted fringe patterns, by adaptively adjusting the pixel-wise intensity of the projected fringe patterns based on the saturated pixels in the captured images of the surface being measured. For the bright regions due to high surface reflectivity and high illumination by the ambient light and surfaces interreflections, the projected intensity is reduced just to be low enough to avoid image saturation. Simultaneously, the maximum intensity of 255 is used for those dark regions with low surface reflectivity to maintain high SNR. Our experiments demonstrate that the proposed technique can achieve higher 3-D measurement accuracy across a surface with a large range of reflectivity variation.

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

    Science.gov (United States)

    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.

  10. Transition-edge sensor pixel parameter design of the microcalorimeter array for the x-ray integral field unit on Athena

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Bandler, S. R.; Betancourt-Martinez, G. L.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Miniussi, A. R.; Porter, F. S.; Sadleir, J. E.; Sakai, K.; Wakeham, N. A.; Wassell, E. J.; Yoon, W.; Bennett, D. A.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Morgan, K. M.; Pappas, C. G.; Reintsema, C. N.; Swetz, D. S.; Ullom, J. N.; Irwin, K. D.; Akamatsu, H.; Gottardi, L.; den Hartog, R.; Jackson, B. D.; van der Kuur, J.; Barret, D.; Peille, P.

    2016-07-01

    The focal plane of the X-ray integral field unit (X-IFU) for ESA's Athena X-ray observatory will consist of 4000 transition edge sensor (TES) x-ray microcalorimeters optimized for the energy range of 0.2 to 12 keV. The instrument will provide unprecedented spectral resolution of 2.5 eV at energies of up to 7 keV and will accommodate photon fluxes of 1 mCrab (90 cps) for point source observations. The baseline configuration is a uniform large pixel array (LPA) of 4.28" pixels that is read out using frequency domain multiplexing (FDM). However, an alternative configuration under study incorporates an 18 × 18 small pixel array (SPA) of 2" pixels in the central 36" region. This hybrid array configuration could be designed to accommodate higher fluxes of up to 10 mCrab (900 cps) or alternately for improved spectral performance (report on the TES pixel designs that are being optimized to meet these proposed LPA and SPA configurations. In particular we describe details of how important TES parameters are chosen to meet the specific mission criteria such as energy resolution, count-rate and quantum efficiency, and highlight performance trade-offs between designs. The basis of the pixel parameter selection is discussed in the context of existing TES arrays that are being developed for solar and x-ray astronomy applications. We describe the latest results on DC biased diagnostic arrays as well as large format kilo-pixel arrays and discuss the technical challenges associated with integrating different array types on to a single detector die.

  11. Fringe Benefits for Administrators in Public Schools, 1979-80. Part 2 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    Science.gov (United States)

    Educational Research Service, Arlington, VA.

    Thirty tables present data from the third biennial survey of fringe benefits among non-superintendent administrators and supervisors in public elementary and secondary school systems. Designed to help school boards and administrators assess their non-cash compensation packages, the national survey drew responses from 803 districts in a random…

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

    Science.gov (United States)

    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…

  13. Fringe Benefits for Administrators in Public Schools, 1981-82. Part 2 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    Science.gov (United States)

    Educational Research Service, Arlington, VA.

    To help school boards and administrative personnel assess the noncash compensation packages in their districts, this fourth biennial survey provides information on fringe benefits given administrators and supervisors (other than superintendents) in a national stratified random sample of 1,044 of the nation's 11,313 public school districts.…

  14. Fringe Benefits for Superintendents in Public Schools, 1979-80. Part 1 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    Science.gov (United States)

    Educational Research Service, Arlington, VA.

    Displayed in 38 tables, the data in this third biennial survey of public school superintendents' fringe benefits are designed to help school boards and administrators assess their non-cash compensation packages. A national sample of 797 school districts--stratified by district enrollment size, expenditure per pupil, and geographic region--supplied…

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

    Directory of Open Access Journals (Sweden)

    Pedro Afonso

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  17. Optical 3D sensor for large objects in industrial application

    Science.gov (United States)

    Kuhmstedt, Peter; Heinze, Matthias; Himmelreich, Michael; Brauer-Burchardt, Christian; Brakhage, Peter; Notni, Gunther

    2005-06-01

    A new self calibrating optical 3D measurement system using fringe projection technique named "kolibri 1500" is presented. It can be utilised to acquire the all around shape of large objects. The basic measuring principle is the phasogrammetric approach introduced by the authors /1, 2/. The "kolibri 1500" consists of a stationary system with a translation unit for handling of objects. Automatic whole body measurement is achieved by using sensor head rotation and changeable object position, which can be done completely computer controlled. Multi-view measurement is realised by using the concept of virtual reference points. In this way no matching procedures or markers are necessary for the registration of the different images. This makes the system very flexible to realise different measurement tasks. Furthermore, due to self calibrating principle mechanical alterations are compensated. Typical parameters of the system are: the measurement volume extends from 400 mm up to 1500 mm max. length, the measurement time is between 2 min for 12 images up to 20 min for 36 images and the measurement accuracy is below 50μm.The flexibility makes the measurement system useful for a wide range of applications such as quality control, rapid prototyping, design and CAD/CAM which will be shown in the paper.

  18. Research Progress on F-P Interference—Based Fiber-Optic Sensors

    Science.gov (United States)

    Huang, Yi Wen; Tao, Jin; Huang, Xu Guang

    2016-01-01

    We review our works on Fabry-Perot (F-P) interferometric fiber-optic sensors with various applications. We give a general model of F-P interferometric optical fiber sensors including diffraction loss caused by the beam divergence and the Gouy phase shift. Based on different structures of an F-P cavity formed on the end of a single-mode fiber, the F-P interferometric optical sensor has been extended to measurements of the refractive index (RI) of liquids and solids, temperature as well as small displacement. The RI of liquids and solids can be obtained by monitoring the fringe contrast related to Fresnel reflections, while the ambient temperature and small displacement can be obtained by monitoring the wavelength shift of the interference fringes. The F-P interferometric fiber-optic sensors can be used for many scientific and technological applications. PMID:27598173

  19. Research Progress on F-P Interference-Based Fiber-Optic Sensors.

    Science.gov (United States)

    Huang, Yi Wen; Tao, Jin; Huang, Xu Guang

    2016-01-01

    We review our works on Fabry-Perot (F-P) interferometric fiber-optic sensors with various applications. We give a general model of F-P interferometric optical fiber sensors including diffraction loss caused by the beam divergence and the Gouy phase shift. Based on different structures of an F-P cavity formed on the end of a single-mode fiber, the F-P interferometric optical sensor has been extended to measurements of the refractive index (RI) of liquids and solids, temperature as well as small displacement. The RI of liquids and solids can be obtained by monitoring the fringe contrast related to Fresnel reflections, while the ambient temperature and small displacement can be obtained by monitoring the wavelength shift of the interference fringes. The F-P interferometric fiber-optic sensors can be used for many scientific and technological applications.

  20. Flux of nitrogen and sediment in a fringe mangrove forest in terminos lagoon, Mexico

    Science.gov (United States)

    Rivera-Monroy, Victor H.; Day, John W.; Twilley, Robert R.; Vera-Herrera, Francisco; Coronado-Molina, Carlos

    Fluxes of dissolved inorganic and organic nitrogen, particulate nitrogen, and total suspended sediments were measured in a fringe mangrove forest using the flume technique during a 15-month period in Terminos Lagoon, Mexico. The 12-m flume extended through a fringe forest from a tidal creek to a basin forest. There was a net import of dissolved inorganic nitrogen (NH +4 and NO -2+NO -3) from the creek and basin forest, while particulate (PN) and dissolved organic nitrogen (DON) were exported to the creek and basin forest. The tidal creek was the principal source of NH +4 (0·53 g m -2 year -1) and NO -2+NO -3 (0·08 g m -2 year -1) to the fringe forest, while the basin forest was the main source of total suspended sediments (TSS; 210 g m -2 year -1). Net export of PN occurred from the fringe forest to the tidal creek (0·52 g m -2 year -1) while less PN was exported to the basin forest (0·06 g m -2 year -1). The decrease in salinity during the rainy season indicated that nutrient concentrations in the tidal creek may have been influenced by inputs from rainfall and river discharge to the lagoon. There was a net import of TSS to the fringe forest from both the creek and basin forests, but the net input was 3·5 times higher at the fringe/basin interface. Particulate material exported from the forest during ebb tides generally had a higher C/N ratio than particulate matter imported into the forest on the flooding tide. This suggested that there was a greater nitrogen demand during ebb tide caused by the export of nitrogen-deficient detritus from fringe and basin mangroves. The exchange of nutrients among the tidal creek, the fringe, and basin forests in Estero Pargo is strongly influenced by seasonal weather forcing, such as winter storms, that can influence the magnitude and direction of water flow. The net annual import of inorganic nitrogen and the export of DON and PN suggest, in contrast to other mangrove systems, that the fringe mangrove forest in Estero Pargo

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Estimate of carbonate production by scleractinian corals at Luhuitou fringing reef, Sanya, China

    Institute of Scientific and Technical Information of China (English)

    SHI Qi; ZHAO MeiXia; ZHANG QiaoMin; YU KeFu; CHEN TianRan; LI Shu; WANG HanKui

    2009-01-01

    Carbonate production by scleractinian corals not only maintains coral reef growth, but also represents an important source of atmospheric carbon dioxide. In this paper the carbonate production by scler-actinian corals at Luhuitou fringing reef, Sanya, Hainan Island, China, is investigated with an ecological census-based method. Averaged carbonate production is 1.16±0.55 kg·m-2·a-1 and 3.52±1.32 kg·m-2·a-1 on the reef flat and reef slope, respectively, depending on the composition and distribution of corals and the intergeneric difference of skeletal growth. In response to the rapidly increasing hu-man impacts, coral carbonate production has decreased by 80%-89% at this fringing reef since the 1960s; as a result, the reef accretion rate declined and became lower than the rate of sea level rise. Further development of the Luhuitou fringing reef will switch significantly from lateral extension sea-wards to vertical growth, reflecting a response of coral reef bio-geomorphic process to strong human impacts under the background of global sea level rise. In addition, decrease in coral carbonate pro-duction reduced CO2 release from this fringing reef. In the future, it is likely that the role played by coral reefs, especially of fringing reefs, in the ocean and even in the global carbon cycle will be modified or weakened by the increasing human impacts.

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

    Science.gov (United States)

    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.

  5. 3D fingerprint imaging system based on full-field fringe projection profilometry

    Science.gov (United States)

    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.

  6. Fourier optics analysis of grating sensors with tilt errors.

    Science.gov (United States)

    Ferhanoglu, Onur; Toy, M Fatih; Urey, Hakan

    2011-06-15

    Dynamic diffraction gratings can be microfabricated with precision and offer extremely sensitive displacement measurements and light intensity modulation. The effect of pure translation of the moving part of the grating on diffracted order intensities is well known. This study focuses on the parameters that limit the intensity and the contrast of the interference. The effects of grating duty cycle, mirror reflectivities, sensor tilt and detector size are investigated using Fourier optics theory and Gaussian beam optics. Analytical findings reveal that fringe visibility becomes <0.3 when the optical path variation exceeds half the wavelength within the grating interferometer. The fringe visibility can be compensated by monitoring the interfering portion of the diffracted order light only through detector size reduction in the expense of optical power. Experiments were conducted with a grating interferometer that resulted in an eightfold increase in fringe visibility with reduced detector size, which is in agreement with theory. Findings show that diffraction grating readout principle is not limited to translating sensors but also can be used for sensors with tilt or other deflection modes.

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

    Science.gov (United States)

    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.

  8. Advanced Triangulation Displacement Sensors

    Science.gov (United States)

    Poteet, Wade M.; Cauthen, Harold K.

    1996-01-01

    Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

  9. Advanced Triangulation Displacement Sensors

    Science.gov (United States)

    Poteet, Wade M.; Cauthen, Harold K.

    1996-01-01

    Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

  10. A hybrid fringe analysis technique for the elimination of random noise in interferometric wrapped phase maps

    Science.gov (United States)

    Bhat, Gopalakrishna K.

    1994-10-01

    A fringe analysis technique, which makes use of the spatial filtering property of the Fourier transform method, for the elimination of random impulsive noise in the wrapped phase maps obtained using the phase stepping technique, is presented. Phase noise is converted into intensity noise by transforming the wrapped phase map into a continuous fringe pattern inside the digital image processor. Fourier transform method is employed to filter out the intensity noise and recover the clean wrapped phase map. Computer generated carrier fringes are used to preserve the sign information. This technique makes the two dimensional phase unwrapping process less involved, because it eliminates the local phase fluctuations, which act as pseudo 2π discontinuities. The technique is applied for the elimination of noise in a phase map obtained using electro-optic holography.

  11. CDA in-situ measurements during Cassini's F-ring plane crossings in 2017

    Science.gov (United States)

    Srama, Ralf; Moragas-Klostermeyer, Georg; Albin, Thomas; Economou, Thanasis; Hsu, Sean; Horanyi, Mihaly; Kempf, Sascha; Li, Yanwei; Postberg, Frank; Simolka, Jonas; Soja, Rachel; Strack, Heiko; Altobelli, Nicolas

    2017-04-01

    The Cosmic Dust Analyzer (CDA) onboard Cassini characterized successfully the dust environment at Saturn since 2004. The instrument measures the primary charge, speed, mass and composition of individual submicron and micron sized dust grains. Starting in December 2016 Cassini performed ring plane crossings at radial distances of 2.48 Saturn radii. For the first time, an in-situ dust detector explored this F-ring region of Saturn. CDA performed density, mass and compositional measurements. Furthermore, the High Rate Detector was activated using a high time and spatial resolution. The spatial resolution on January 2nd (2017) was as low as 2000 meters. Here, we do report preliminary results of the in-situ measurements of three F-ring orbit crossings. The relative encounter speed between Cassini and F-ring particles was approximately 20 km per second.

  12. A single-gap transflective liquid crystal driven by fringe and vertical electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Young Jin; Chin, Mi Hyung; Kim, Jin Ho; Her, Jung Hwa; Lee, Seung Hee [Polymer BIN Fusion Research Center, Department of Polymer Nano-Science and Technology, Chonbuk National University, Chonju, Chonbuk 561-756 (Korea, Republic of); Jin, Hyun Suk; Kim, Byeong Koo, E-mail: lsh1@chonbuk.ac.k [Mobile Product Development Department, LG Display Co., Ltd., Gumi, Gyungbuk 730-350 (Korea, Republic of)

    2009-07-21

    A single-gap transflective liquid-crystal display driven by a fringe electric field in the transmissive (T) region and a vertical electric field in the reflective (R) region was designed. In the device, a homogeneously aligned liquid crystal (LC) rotates almost in plane by a fringe field in the T-region whereas the LC tilts upwards by a vertical field in the R-region. A high surface pre-tilt angle of the LC in the R-region is achieved through polymerization of an UV curable reactive mesogen monomer at the surfaces and thus the effective cell retardation in the R-region becomes half of that in the T-region. Consequently, a transflective display driven by a vertical and a fringe electric field with a single cell gap and single gamma curves is realized.

  13. Far-infrared Michelson interferometer for tokamak electron density measurements using computer-generated reference fringes

    Energy Technology Data Exchange (ETDEWEB)

    Krug, P.A.; Stimson, P.A.; Falconer, I.S.

    1986-11-01

    A simple far-infrared interferometer which uses the 394 ..mu..m laser line from optically-pumped formic acid vapour to measure tokamak electron density is described. This interferometer is unusual in requiring only one detector and a single probing beam since reference fringes during the plasma shot are obtained by computer interpolation between the fringes observed immediately before and after the shot. Electron density has been measured with a phase resolution corresponding to + - 1/20 wavelength fringe shift, which is equivalent to a central density resolution of + - 0.1 x 10/sup 19/ m/sup -3/ for an assumed parabolic density distribution in a plasma of diameter of 0.2 m, and with a time resolution of 0.2 ms.

  14. Bandwidth smearing in optical interferometry: Analytic model of the transition to the double fringe packet

    CERN Document Server

    Lachaume, Régis

    2012-01-01

    Bandwidth smearing is a chromatic aberration due to the finite frequency bandwidth. In long-baseline optical interferometry terms, it is when the angular extension of the source is greater than the coherence length of the interferogram. As a consequence, separated parts of the source will contribute to fringe packets that are not fully overlapping; it is a transition from the classical interferometric regime to a double or multiple fringe packet. While studied in radio interferometry, there has been little work on the matter in the optical, where observables are measured and derived in a different manner, and are more strongly impacted by the turbulent atmosphere. We provide here the formalism and a set of usable equations to model and correct for the impact of smearing on the fringe contrast and phase, with the case of multiple stellar systems in mind. The atmosphere is briefly modeled and discussed.

  15. Separating Citizenization and Land Requisition: New Urbanization in Beijing’s Rural-Urban Fringe Area

    Institute of Scientific and Technical Information of China (English)

    Cui; Xianghua; Li; Min

    2015-01-01

    Through rapid urbanization, Beijing is entering into the advanced stage of industrialization and urbanization, while it, like many other cities, is faced with issues of low-quality urbanization and citizenization. Under the infl uences of both urbanization and suburbanization, the sprawling rural-urban fringe area becomes a tough issue to resolve. The reconstruction of 50 key villages in Beijing’s rural-urban fringe area that was started in 2010 has initially changed the citizenization-land requisition coupling model through recombining land use right, household registration, and social security to make farmers become new-type citizens with land use right. The practice in Beijing reveals that the fringe issues are caused by the new and old dual structures which are formed as a result of the urban-rural dual land system, and that the path to new urbanization in China is to separate citizenization from land requisition, so as to achieve the transformation towards a proactive urbanization.

  16. Separated Fringe Packet Observations with the CHARA Array II: $\\omega$ Andromeda, HD 178911, and {\\xi} Cephei

    CERN Document Server

    Farrington, Christopher D; Mason, Brian D; Hartkopf, William I; Mourard, Denis; Moravveji, Ehsan; McAlister, Harold A; Turner, Nils H; Sturmann, Laszlo; Sturmann, Judit

    2014-01-01

    When observed with optical long-baseline interferometers (OLBI), components of a binary star which are sufficiently separated produce their own interferometric fringe packets; these are referred to as Separated Fringe Packet (SFP) binaries. These SFP binaries can overlap in angular separation with the regime of systems resolvable by speckle interferometry at single, large-aperture telescopes and can provide additional measurements for preliminary orbits lacking good phase coverage, help constrain elements of already established orbits, and locate new binaries in the undersampled regime between the bounds of spectroscopic surveys and speckle interferometry. In this process, a visibility calibration star is not needed, and the separated fringe packets can provide an accurate vector separation. In this paper, we apply the SFP approach to {\\omega} Andromeda, HD 178911, and {\\xi} Cephei with the CLIMB three-beam combiner at the CHARA Array. For these systems we determine component masses and parallax of 0.963${\\pm...

  17. Ramsey fringes in a single InGaAs/GaAs quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Ester, P.; Stufler, S.; Michaelis Vasconcellos, S. de; Zrenner, A. [Universitaet Paderborn, Warburger Strasse 100, 33098 Paderborn (Germany); Bichler, M. [Walter Schottky Institut, TU Muenchen, Am Coulombwall, 85748 Garching (Germany)

    2006-08-15

    We report the observation of Ramsey fringes in single InGaAs/GaAs quantum dots. With double pulse p/2 excitation it is possible to control the occupancy and the phase of a quantum dot. The occupancy of the quantum dot oscillates with detuning. These Ramsey fringes are caused by a voltage dependent detuning of the QD. Due to the double pulse excitation the spectral sensitivity is strongly enhanced as compared to single pulse experiments. At long delay times we are able to resolve extremely narrow spectral fringes, clearly below the homogeneous linewidth of the underlying QD two level system. Our results demonstrate precision measurements on single quantum dots with strong implications for future quantum gates and quantum measurements. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Diffusive-dispersive mass transfer in the capillary fringe: Impact of water table fluctuations and heterogeneities

    DEFF Research Database (Denmark)

    Grathwohl, Peter; Haberer, Cristina; Ye, Yu;

    Diffusive–dispersive mass transfer in the capillary fringe is important for many groundwater quality issues such as transfer of volatile compounds into (and out of) the groundwater, the supply of oxygen for aerobic degradation of hydrocarbons as well as for precipitation of minerals (e.g. iron...... hydroxides). 2D-laboratory scale experiments were used to investigate the transfer of oxygen into groundwater under non-reactive and reactive conditions, at steady state and with water table fluctuations. Results show that transfer of oxygen is limited by transverse dispersion in the capillary fringe...... and the dispersion coefficients are the same as below the water table. Water table fluctuations cause temporarily increased fluxes of oxygen into groundwater during draining conditions and entrapped air after water table rise. High-permeability inclusions in the capillary fringe enhance mass transfer of oxygen...

  19. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under th

  20. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under

  1. Personal protective equipment with integrated POF sensors

    Science.gov (United States)

    Witt, J.; Schukar, M.; Krebber, K.; Pažoutová, H.; Demuth, J.; Santostefano, N.; Mäkinen, H.; Pietrowski, P.

    2013-05-01

    Within the EU project i-Protect fibre optic sensors for measuring heart rate, respiratory rate and skin temperature are being developed. The plastic optical fibre (POF) sensors are based on macrobending effects, photoplethysmography and fluorescence thermometry. The sensors and monitoring units are integrated into underwear and are communicating wireless via body area network and communication unit with the rescue command centre. All sensors can be removed from the underwear to allow washing the textile. First prototypes of the fibre optic sensors were tested in comparison to commercial reference sensors.

  2. PSF and MTF Measurement Methods for Thick CCD Sensor Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, P.Z.; Kotov, I.; Frank, J.; O' Connor, P.; Radeka, V.; Lawrence, D.M.

    2010-06-30

    Knowledge of the point spread function (PSF) of the sensors to be used in the Large Synoptic Survey Telescope (LSST) camera is essential for optimal extraction of subtle galaxy shape distortions caused by gravitational weak lensing. We have developed a number of techniques for measuring the PSF of candidate CCD sensors to be used in the LSST camera, each with its own strengths and weaknesses. The two main optical PSF measurement techniques that we use are the direct Virtual Knife Edge (VKE) scan as developed by Karcher, et al. and the indirect interference fringe method after Andersen and Sorensen that measures the modulation transfer function (MTF) directly. The PSF is derived from the MTF by Fourier transform. Other non-optical PSF measurement techniques that we employ include {sup 55}Fe x-ray cluster image size measurements and statistical distribution analysis, and cosmic ray muon track size measurements, but are not addressed here. The VKE technique utilizes a diffraction-limited spot produced by a Point-Projection Microscope (PPM) that is scanned across the sensor with sub-pixel resolution. This technique closely simulates the actual operating condition of the sensor in the telescope with the source spot size having an f/number close to the actual telescope design value. The interference fringe method uses a simple equal-optical-path Michelson-type interferometer with a single-mode fiber source that produces interference fringes with 100% contrast over a wide spatial frequency range sufficient to measure the MTF of the sensor directly. The merits of each measurement technique and results from the various measurement techniques on prototype LSST sensors are presented and compared.

  3. A threshold voltage model for high-κgate-dielectric MOSFETs considering fringing-field effect

    Institute of Scientific and Technical Information of China (English)

    Ji Feng; Xu Jing-Ping; Lai Pui-To

    2007-01-01

    In this paper, a threshold voltage model for high-κgate-dielectric metal-oxide-semiconductor field-effect transistors (MOSFETs) is developed, with more accurate boundary conditions of the gate dielectric derived through a conformal mapping transformation method to consider the fringing-field effects including the influences of high-κgate-dielectric and sidewall spacer. Comparing with similar models, the proposed model can be applied to general situations where the gate dielectric and sidewall spacer can have different dielectric constants. The influences of sidewall spacer and high-κgate dielectric on fringing field distribution of the gate dielectric and thus threshold voltage behaviours of a MOSFET are discussed in detail.

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

    Science.gov (United States)

    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.

  5. Pixelated speckle image holography carrier fringes for efficient superimposed light harvesting in organic solar cells

    Science.gov (United States)

    Zhou, Lei; Li, Yan-Qing; Chen, Jing-De; Ou, Qing-Dong; Tang, Jian-Xin; Zhou, Yun; Lin, Yi; Wei, Huai-Xin

    2017-06-01

    An inverted organic solar cell (OSC) device structure by incorporating pixelated speckle image holography carrier fringes (SIHFs) for efficient superimposed light harvesting is demonstrated. The proposed SIHF based OSCs yield an 18.2% increase in power conversion efficiency (PCE) compared to that of the flat control devices. Moreover, compared to the common two-dimensional (2D) periodic grating patterned OSCs, SIHF based devices achieve 7.8% higher short-circuit current (JSC) and 10.0% higher PCE. This observable improvement in PCE of SIHF based OSCs is mainly ascribed to the geometric effect due to the unique chaotic carrier fringes of SIHFs.

  6. Urban fringe renewal with urban catalysts elements: connections in an unconnected area

    OpenAIRE

    Yanru, Yang

    2014-01-01

    Based on Santa Coloma as a main case,analyzing how can be update there in this crisis situation to do suitable interventions to achieve a great effect. After analyzing the Santa Coloma area,I pay attention to its urban marginality.It has the territorial marginality,the marginality of the relationship with Barcelona,the marginality of the people and life style and so on. Urban fringe is corresponding the city center, the city of mainstream.The socalled "fringe" can be underst...

  7. Microscopic structured light 3D profilometry: Binary defocusing technique vs. sinusoidal fringe projection

    Science.gov (United States)

    Li, Beiwen; Zhang, Song

    2017-09-01

    This paper compares the binary defocusing technique with conventional sinusoidal fringe projection under two different 3D microscopic profilometry systems: (1) both camera and projector use telecentric lenses and (2) only camera uses a telecentric lens. Our simulation and experiments found that the binary defocusing technique is superior to the traditional sinusoidal fringe projection method by improving the measurement resolution approximately 19%. Finally, by taking the speed advantage of the binary defocusing technique, we presented a high-speed (500 Hz) and high-resolution (1600×1200) 3D microscopic profilometry system that could reach kHz.

  8. Fringing field correction of the second-order angular aberration in sector field electron energy analyzers

    Energy Technology Data Exchange (ETDEWEB)

    Yavor, M.I. [Institute for Analytical Instrumentation RAS, 190103 St. Petersburg (Russian Federation)], E-mail: mikhail.yavor@gmail.com; Belov, V.D.; Pomozov, T.V. [Institute for Analytical Instrumentation RAS, 190103 St. Petersburg (Russian Federation)

    2008-12-15

    A new way of correcting the second-order angular aberration in sector field and polar-toroidal electron energy analyzers with object and image located outside the field is proposed. Correction is performed by biasing the optic axis electrostatic potential inside the analyzer with respect to the potential of surrounding field-free space. The strength of the correcting aberration concentrated in the fringing field regions of the analyzer is calculated with the aid of the fringing field integral method. The described correction allows achieving second-order focusing and thus increasing the energy resolving power in sector field analyzers, in particular used for angle resolved energy measurements.

  9. Speckle and fringe dynamics in imagingspeckle-pattern interferometry for spatial-filtering velocimetry

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Iversen, Theis F. Q.; Yura, Harold T.

    2011-01-01

    This paper analyzes the dynamics of laser speckles and fringes, formed in an imaging-speckle-pattern interferometer with the purpose of sensing linear three-dimensional motion and out-of-plane components of rotation in real time, using optical spatial-filtering-velocimetry techniques. The ensemble...... and direction of all three linear displacement components of the object movement can be determined. Simultaneously, out-ofplane rotation of the object including the corresponding directions can be determined from the spatial gradient of the in-plane fringe motion throughout the observation plane. The theory...

  10. Functional and performance tests of the fringe and flexure tracking system for LINC-NIRVANA

    Science.gov (United States)

    Rauch, C.; Eckart, A.; Horrobin, M.; Lindhorst, B.; Rost, S.; Smajić, S.; Straubmeier, C.; Tremou, E.; Wank, I.; Zuther, J.

    2012-07-01

    LINC-NIRVANA is a near-Infrared homothetic, beam combining camera for the Large Binocular Telescope that offers Multi-Conjugate Adaptive Optics wavefront correction and fringe tracking to achieve a time-stable fringe pattern. Therefore, the trajectory of the reference source has to be followed as accurate as possible for a precise point spread function acquisition. The presented measurement campaign shows detector positioning errors exceeding the requirements significantly and indicates that these huge errors arise from the software, while the installed hardware matches the requirements.

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

    Science.gov (United States)

    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.

  12. Ion Composition of the Thermal Plasma in the F-Ring Region of Saturn

    Science.gov (United States)

    Ip, W. H.; Tseng, W. L.; Hsu, J. K.; Wei, C. E.; Shen, C. H.

    2016-12-01

    In the final phase of the Cassini mission in 2016-2017, the spacecraft will first move to orbits with periapse outside the F-ring and then to orbits grazing the upper atmosphere of Saturn. These trajectories will provide the unique opportunity to sample the structures and composition of Saturn's ionosphere but also those of the main rings. From an assessment of the neutral gas and plasma environment of the rings, we investigate the formation of molecular ions and nano-grains in the areas to be probed by Cassini during its F-ring and Proximal orbits

  13. Ramsey Fringes in an Electric-Field-Tunable Quantum Dot System

    Science.gov (United States)

    Stufler, S.; Ester, P.; Zrenner, A.; Bichler, M.

    2006-01-01

    We report on Ramsey fringes measured in a single InGaAs/GaAs quantum dot two-level system. We are able to control the transition energy of the system by Stark effect tuning. In combination with double pulse excitation this allows for a voltage controlled preparation of the phase and the occupancy of the two-level system. For long pulse delay times we observe extremely narrow fringes with spectral width below the homogeneous linewidth of the system. Implications on quantum information processing are discussed.

  14. The linkage between car-related fringe benefits and the travel behavior of knowledge workers

    DEFF Research Database (Denmark)

    Bendit, Eduard; Frenkel, Amnon; Kaplan, Sigal

    2011-01-01

    This study focuses on the linkage between car-related fringe benefits and the travel behavior of knowledge workers in commute and leisure trips. Specifically, this study compares the commuting and leisure travel behavior of knowledge workers who receive either a company-car or car allowance...... and travel times and non-sustainable transport modes, and (iii) high frequency of long-distance leisure trips. Policy implications include (i) directing policies towards reducing car ownership induced by car-related fringe benefits, (ii) encouraging company-car holders to ‘pay their way’, and (iii......) encouraging workers to use sustainable transport modes for commuting and leisure travel....

  15. 26 CFR 1.132-1T - Exclusion from gross income of certain fringe benefits-1985 through 1988 (temporary).

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Exclusion from gross income of certain fringe benefits-1985 through 1988 (temporary). 1.132-1T Section 1.132-1T Internal Revenue INTERNAL REVENUE SERVICE... 1988 (temporary). (a) In general. Gross income does not include any fringe benefit which qualifies as...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. Nonlinear effects of a modal domain optical fiber sensor in a vibration suppression control loop for a flexible structure

    Science.gov (United States)

    Lindner, D. K.; Zvonar, G. A.; Baumann, W. T.; Delos, P. L.

    1993-01-01

    Recently, a modal domain optical fiber sensor has been demonstrated as a sensor in a control system for vibration suppression of a flexible cantilevered beam. This sensor responds to strain through a mechanical attachment to the structure. Because this sensor is of the interferometric type, the output of the sensor has a sinusoidal nonlinearity. For small levels of strain, the sensor can be operated in its linear region. For large levels of strain, the detection electronics can be configured to count fringes. In both of these configurations, the sensor nonlinearity imposes some restrictions on the performance of the control system. In this paper we investigate the effects of these sensor nonlinearities on the control system, and identify the region of linear operation in terms of the optical fiber sensor parameters.

  19. Comparison of phase recovery methods in spiral speckle pattern interferometry correlation fringes

    Science.gov (United States)

    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.

  20. 29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

    Science.gov (United States)

    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 wages...

  1. A Pitch-variation Moiré Fringes Method of Temporal Phase Unwrapping Profilometry

    Institute of Scientific and Technical Information of China (English)

    Tian Jin-dong; Peng Xiang; Zhao Xiao-bo

    2007-01-01

    A method of pitch-variation moiré fringes is proposed to realize the temporal phase unwrapping for three-dimensional pattern by rotating two gratings. Furthermore a five-point fitting method is used to automatically compute the central duced to process the three-dimensional reconstruction. The theoretical analysis and experimental results show the validity of the proposed method.

  2. Application of robust color composite fringe in flip-chip solder bump 3-D measurement

    Science.gov (United States)

    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.

  3. Third-order particle motion through the fringing field of a homogeneous bending magnet

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, B. (2. Physikalisches Inst. der Justus-Liebig-Univ., Giessen (Germany)); Wollnik, H. (2. Physikalisches Inst. der Justus-Liebig-Univ., Giessen (Germany))

    1994-05-01

    The ion trajectories through the extended fringing field of a homogeneous magnet are approximated by analytic formulas including the effects of inclined and curved field boundaries. The results are expressed by transfer matrices. All expressions are compared to numerical integrations through typical field distributions. (orig.)

  4. Beam transport optics of dipole fringe field in the framework of third-order matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Sagalovsky, L. (Argonne National Lab. (USA))

    1990-12-01

    The paper describes analytical methods for studying the optical aberrations of charged particles' orbits in an extended fringing field of a dipole magnet. Solutions are obtained up to the third order in the formalism of the transfer matrix theory. (orig.).

  5. Absolute height measurement of specular surfaces with modified active fringe reflection photogrammetry

    Science.gov (United States)

    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.

  6. Telecentric 3D profilometry based on phase-shifting fringe projection.

    Science.gov (United States)

    Li, Dong; Liu, Chunyang; Tian, Jindong

    2014-12-29

    Three dimensional shape measurement in the microscopic range becomes increasingly important with the development of micro manufacturing technology. Microscopic fringe projection techniques offer a fast, robust, and full-field measurement for field sizes from approximately 1 mm2 to several cm2. However, the depth of field is very small due to the imaging of non-telecentric microscope, which is often not sufficient to measure the complete depth of a 3D-object. And the calibration of phase-to-depth conversion is complicated which need a precision translation stage and a reference plane. In this paper, we propose a novel telecentric phase-shifting projected fringe profilometry for small and thick objects. Telecentric imaging extends the depth of field approximately to millimeter order, which is much larger than that of microscopy. To avoid the complicated phase-to-depth conversion in microscopic fringe projection, we develop a new system calibration method of camera and projector based on telecentric imaging model. Based on these, a 3D reconstruction of telecentric imaging is presented with stereovision aided by fringe phase maps. Experiments demonstrated the feasibility and high measurement accuracy of the proposed system for thick object.

  7. Utilization of fringe projection technique for evaluation of wound dimensions and of healing progress

    Science.gov (United States)

    Saito, Marcia T.; Yoshimura, Elisabeth M.; Palácios, Francisco F.; Lino, Antonio C. L.; Palácios, Guillermo F.; Sousa, Marcelo V. P.

    2013-03-01

    Background: The methods used for evaluating wound dimensions, especially the chronic ones, are invasive and inaccurate. The fringe projection technique with phase shift is a non-invasive, accurate and low-cost optical method. Objective: The aim is to validate the technique through the determination of dimensions of objects of known topography and with different geometries and colors to simulate the wounds and tones of skin color. Taking into account the influence of skin wound optical factors, the technique will be used to evaluate actual patients' wound dimensions and to study its limitations in this application. Methods: Four sinusoidal fringe patterns, displaced ¼ of period each, were projected onto the objects surface. The object dimensions were obtained from the unwrapped phase map through the observation of the fringe deformations caused by the object topography and using phase shift analysis. An object with simple geometry was used for dimensional calibration and the topographic dimensions of the others were determined from it. After observing the compatibility with the data and validating the method, it was used for measuring the dimensions of real patients' wounds. Results and Conclusions: The discrepancies between actual topography and dimensions determined with Fringe Projection Technique and for the known object were lower than 0.50 cm. The method was successful in obtaining the topography of real patient's wounds. Objects and wounds with sharp topographies or causing shadow or reflection are difficult to be evaluated with this technique.

  8. Electrically actuated MEMS resonators: Effects of fringing field and nonlinear viscoelasticity

    Science.gov (United States)

    Farokhi, Hamed; Ghayesh, Mergen H.

    2017-10-01

    This paper studies the nonlinear electromechanical response of a MEMS resonator numerically. A nonlinear continuous multi-physics model of the MEMS resonator is developed taking into account the effects of fringing field, size, residual axial load, and viscoelasticity. Moreover, both longitudinal and transverse motions are accounted for in the system modelling and simulations. The equations of motion of the MEMS resonator are obtained employing Hamilton's principle together with the modified version of the couple stress based theory (to account for size effects) and the Kelvin-Voigt model (to account for nonlinear energy dissipation). The Meijs-Fokkema electrostatic load formula is used to reliably model the fringing field effects. The continuous multi-physics model, consisting of geometrical, electrical, and viscos nonlinearities is discretised via a weighted-residual method, yielding a set of nonlinearly coupled ordinary differential equations (ODEs). The resultant set of ODEs is solved numerically when the microresonator is actuated by a biased DC voltage and an AC voltage. The results of the numerical simulations are presented in the form of DC voltage-deflection, DC voltage-natural frequency, and AC frequency-displacement diagrams. The effects of fringing field, residual axial load, small-scale, and nonlinear energy dissipation are highlighted. It is shown that fringing field effects are significant on both static and dynamic electromechanical responses of the MEMS resonator.

  9. High-speed digital color fringe projection technique for three-dimensional facial measurements

    Science.gov (United States)

    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.

  10. Novel method of detecting movement of the interference fringes using one-dimensional PSD.

    Science.gov (United States)

    Wang, Qi; Xia, Ji; Liu, Xu; Zhao, Yong

    2015-06-02

    In this paper, a method of using a one-dimensional position-sensitive detector (PSD) by replacing charge-coupled device (CCD) to measure the movement of the interference fringes is presented first, and its feasibility is demonstrated through an experimental setup based on the principle of centroid detection. Firstly, the centroid position of the interference fringes in a fiber Mach-Zehnder (M-Z) interferometer is solved in theory, showing it has a higher resolution and sensitivity. According to the physical characteristics and principles of PSD, a simulation of the interference fringe's phase difference in fiber M-Z interferometers and PSD output is carried out. Comparing the simulation results with the relationship between phase differences and centroid positions in fiber M-Z interferometers, the conclusion that the output of interference fringes by PSD is still the centroid position is obtained. Based on massive measurements, the best resolution of the system is achieved with 5.15, 625 μm. Finally, the detection system is evaluated through setup error analysis and an ultra-narrow-band filter structure. The filter structure is configured with a one-dimensional photonic crystal containing positive and negative refraction material, which can eliminate background light in the PSD detection experiment. This detection system has a simple structure, good stability, high precision and easily performs remote measurements, which makes it potentially useful in material small deformation tests, refractivity measurements of optical media and optical wave front detection.

  11. Transport-related fringe benefits: implications for moving and the journey to work

    NARCIS (Netherlands)

    Ommeren, van Jos; Vlist, van der A.J.; Nijkamp, Peter

    2006-01-01

    Firms offer compensation not only through wages, but also offer transport-related fringe benefits such as transport benefits (company cars, travel, and parking benefits) and relocation benefits to job applicants. We argue that these benefits are not randomly offered to employees, but depend on the j

  12. Transport-related fringe benefits: implications for moving and the journey to work

    NARCIS (Netherlands)

    Ommeren, van Jos; Vlist, van der A.J.; Nijkamp, Peter

    2006-01-01

    Firms offer compensation not only through wages, but also offer transport-related fringe benefits such as transport benefits (company cars, travel, and parking benefits) and relocation benefits to job applicants. We argue that these benefits are not randomly offered to employees, but depend on the

  13. On the development of a low-cost rigid borescopic fringe projection system

    Science.gov (United States)

    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.

  14. New approach for identifying the zero-order fringe in variable wavelength interferometry

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. Simultaneous estimation of unwrapped phase and phase derivative from a closed fringe pattern

    Science.gov (United States)

    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.

  17. 44 CFR 208.40 - Reimbursement of fringe benefit costs during Activation.

    Science.gov (United States)

    2010-10-01

    ... System Member, Bill DHS for a pro-rata share of the premium based on the number of base hours worked...-rata share of the premium based on the number of hours each System Member worked during Activation The... people employed full-time during the year, Bill DHS for a pro-rata share of those fringe benefit...

  18. Questioning the medical fringe: the "cultural doxy" of Catholic hydropathy in Belgium, 1890-1914.

    Science.gov (United States)

    Peeters, Evert

    2010-01-01

    The relationship between orthodox (mainstream) medicine and heterodox (fringe) medicine during the nineteenth century continues to puzzle historians of medicine. Though many have qualified the sharp antagonism between the two as a (biased) historical construct, it remains difficult to lay bare the common problems that structured mainstream and fringe. In this contribution on the reception of hydrotherapy in the Belgian fin de siècle, I attempt to rethink the oppositional character of nineteenth-century fringe medicine at an empirical level. In many ways, I argue, Belgian hydropaths were prototypical proponents of medical heterodoxy, as they defended neohumoralist medical conceptions and shared an integrated Catholic "cosmology". Their moderate critique of bacteriological science, however, also echoed the unease felt by many established physicians. In their pretheoretical beliefs about the healer's intuition, they voiced traditional conceptions that stemmed not from the fringe but from everyday bedside medicine. The popularity of hydrotherapy, I argue, reflected one of many attempts to save a common "cultural doxy" shared by established physicians and heterodox healers alike, in the wake of bacteriology's analysis and standardization.

  19. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Science.gov (United States)

    2010-04-01

    ... rule. For example, the fact that $180 ($15 per month for 12 months) worth of transit passes can be... entertainment is not excludable as a de minimis fringe. (d) Special rules—(1) Transit passes. A transit pass... cards that enable an individual to travel on the transit system. The exclusion provided in...

  20. First 230 GHz VLBI Fringes on 3C 279 using the APEX Telescope

    CERN Document Server

    Wagner, J; 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

    2015-01-01

    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). We installed VLBI equipment and measured the APEX station position to 1 cm accuracy (1 sigma). We then observed 3C 279 on 2012 May 7 in a 5 hour 230 GHz VLBI track with baseline lengths of 2800 M$\\lambda$ to 7200 M$\\lambda$ and a finest fringe spacing of 28.6 micro-arcseconds. Fringes were detected on all baselines with SNRs of 12 to 55 in 420 s. The correlated flux density on the longest baseline was ~0.3 Jy/beam, out of a total flux density of 19.8 Jy. Visibility data suggest an emission region <38 uas 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 10^10 K. Lastly, we find an upper limit of 20% on the linear polarization fraction at a fringe spacing of ~38 uas. With APEX the angul...

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

    CERN Document Server

    Petrov, Romain G; Bresson, Yves; Agabi, Karim; Folcher, Jean-Pierre; Elhalkouj, Thami; Lagarde, Stephane; Benkhaldoun, Zouhair

    2016-01-01

    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...

  2. the impact of forest reserves on livelihoods of fringe communities in ...

    African Journals Online (AJOL)

    User

    and forest products at local market and for ex- ... negative impact on the livelihood of the people. This study was ..... Socio-Economic Characteristics of Fringe .... proximity to Kumasi, the cultural hub of ... It became clear that if the tourism poten-.

  3. Sensor Integration Using State Estimators

    Directory of Open Access Journals (Sweden)

    Jens G. Balchen

    1991-04-01

    Full Text Available Means for including very different types of sensors using one single unit are described. Accumulated data are represented using an updatable dynamic model, a Kalman filter. The scheme handles common phenomena such as skewed sampling, finite resolution measurements and information delays. Included is an example where 3D motion information is collected by one or more vision sensors.

  4. Identifying unknown nanocrystals by fringe fingerprinting in two dimensions and free-access crystallographic databases

    Science.gov (United States)

    Moeck, Peter; Čertik, Ondřej; Seipel, Bjoern; Groebner, Rebecca; Noice, Lori; Upreti, Girish; Fraundorf, Philip; Erni, Rolf; Browning, Nigel D.; Kiesow, Andreas; Jolivet, Jean-Pierre

    2005-11-01

    New needs to determine the crystallography of nanocrystals arise with the advent of science and engineering on the nanometer scale. Direct space high-resolution phase-contrast transmission electron microscopy (HRTEM) and atomic resolution Z-contrast scanning TEM (Z-STEM), when combined with tools for image-based nanocrystallography possess the capacity to meet these needs. This paper introduces such a tool, i.e. fringe fingerprinting in two dimensions (2D), for the identification of unknown nanocrystal phases and compares this method briefly to qualitative standard powder X-ray diffractometry (i.e. spatial frequency fingerprinting). Free-access crystallographic databases are also discussed because the whole fingerprinting concept is only viable if there are comprehensive databases to support the identification of an unknown nanocrystal phase. This discussion provides the rationale for our ongoing development of a dedicated free-access Nano-Crystallography Database (NCD) that contains comprehensive information on both nanocrystal structures and morphologies. The current status of the NCD project and plans for its future developments are briefly outlined. Although feasible in contemporary HRTEMs and Z-STEMs, fringe fingerprinting in 2D (and image-based nanocrystallography in general) will become much more viable with the increased availability of aberration-corrected transmission electron microscopes. When the image acquisition and interpretation are, in addition, automated in such microscopes, fringe fingerprinting in 2D will be able to compete with powder X-ray diffraction for the identification of unknown nanocrystal phases on a routine basis. Since it possesses a range of advantages over powder X-ray diffractometry, e.g., fringe fingerprint plots contain much more information for the identification of an unknown crystal phase, fringe fingerprinting in 2D may then capture a significant part of the nanocrystal metrology market.

  5. Metamaterial Sensors

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2013-01-01

    Full Text Available Metamaterials have attracted a great deal of attention due to their intriguing properties, as well as the large potential applications for designing functional devices. In this paper, we review the current status of metamaterial sensors, with an emphasis on the evanescent wave amplification and the accompanying local field enhancement characteristics. Examples of the sensors are given to illustrate the principle and the performance of the metamaterial sensor. The paper concludes with an optimistic outlook regarding the future of metamaterial sensor.

  6. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built us

  7. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built us

  8. 基于Goldstein滤波的数字散斑条纹图降噪方法%Digital Speckle Fringe Pattern Denoising Method Based on Goldstein Filtering

    Institute of Scientific and Technical Information of China (English)

    顾国庆; 王开福; 许星

    2012-01-01

    有效去除数字散斑条纹图中的噪声是散斑干涉测量技术中的关键问题.提出了一种基于Goldstein滤波的数字散斑条纹图平滑方法.该方法需要将散斑条纹图中的干涉相位转换为矢量空间中的单位矢量,并进行快速傅里叶变换(FFT),得到其频谱,然后对频谱进行加权处理,从而抑制噪声的频率成分,再将加权处理后的频谱变换到空间域,计算干涉相位,得到原始散斑条纹图的滤波结果.将该滤波方法运用于四步相移数字散斑干涉条纹图像处理.实验结果表明,该方法在滤除散斑噪声的同时能够有效地保护散斑条纹图的轮廓和细节信息,增强了散斑干涉条纹的对比度.%Getting rid of the noises is the key problem in digital speckle pattern interferometry (DSPI). A method based on Goldstein filtering for digital speckle fringe pattern smoothing is proposed. This algorithm maps the raw speckle interferogram to unit vectors in vector space and transforms them to frequency domain by fast Fourier transform (FFT). Then the weighting function is selected to weight the spectrum. The frequency of the speckle noises can be suppressed. Finally, the processed spectrum is transformed to space domain by inverse FFT and phases of filtering results are calculated. The filtering technique is used for the four-step phase-shifting digital speckle image processing. The experimental result shows that the speckle noise in the speckle fringe patterns is removed efficiently and the information of the fringe contour and structure is well preserved. The proposed method can increase the contrast of DSPI fringes.

  9. Parallel plate capacitor analogy of equatorial plasma bubble and associated fringe fields with implications to equatorial valley region irregularities

    Science.gov (United States)

    Mukherjee, S.; Patra, A. K.

    2014-08-01

    VHF radar echoes from the valley region plasma irregularities, displaying ascending pattern, are often observed during the active phase of equatorial plasma bubble in the close vicinity of the geomagnetic equator and have been attributed to bubble-related fringe field effect. These irregularities however are not observed at a few degrees away from the equator. In this paper, we attempt to understand this contrasting observational result by comparing fringe field at the geomagnetic equator and low latitudes. We use parallel plate capacitor analogy of equatorial plasma bubble and choose a few capacitor configurations, consistent with commonly observed dimension and magnetic field-aligned property of plasma bubble, for computing fringe field. Results show that fringe field decreases significantly with decreasing altitude as expected. Further, fringe field decreases remarkably with latitude, which clearly indicates the role of magnetic field-aligned property of plasma bubble in reducing the magnitude of fringe field at low latitudes compared to that at the geomagnetic equator. The results are presented and discussed in the light of current understanding of plasma bubble-associated fringe field-induced plasma irregularities in the valley region.

  10. Delineating Urban Fringe Area by Land Cover Information Entropy—An Empirical Study of Guangzhou-Foshan Metropolitan Area, China

    Directory of Open Access Journals (Sweden)

    Junyi Huang

    2016-05-01

    Full Text Available Rapid urbanization has caused many environmental problems, such as the heat island effect, intensifying air pollution, pollution from runoff, loss of wildlife habitat, etc. Accurate evaluations of these problems demand an accurate delineation of the spatial extent of the urban fringe. Conceptual and analytical ambiguity of the urban fringe and a general lack of consensus among researchers have made its measurement very difficult. This study reports a compound and reliable method to delineate the urban fringe area using a case study. Based on the 'fringe effect' theory in landscape ecology, the existing land cover information entropy model for defining the urban fringe is renewed by incorporating scale theory, cartography and urban geography theory. Results show that the urban fringe area of Guangzhou and Foshan metropolitan area covers an area of 2031 km2, and it occupies over 31% of the total study area. Result evaluation by industry structure data shows satisfactory correspondence with different land cover types. This paper reports the method and outcome of an attempt to provide an objective, repeatable and generally applicable method for mapping its spatial extent from remote sensing imageries, and could be beneficial to relevant urban studies and urban fringe management projects.

  11. Recovery of absolute phases for the fringe patterns of three selected wavelengths with improved anti-error capability

    Science.gov (United States)

    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. The particle motion through the fringing field of a toroidal condenser in a third-order approximation

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, B. [Giessen Univ. (Germany). 2. Physikalisches Inst.; Wollnik, H. [Giessen Univ. (Germany). 2. Physikalisches Inst.

    1995-09-01

    The ion trajectories through the extended fringing field of a toroidal condenser are calculated including the effects of curved field boundaries. The optical fringing-field effects are expressed by analytical formulas including fringing-field integrals using the transfer matrix method. These formulas describe in an effective third-order approximation all effects in the plane of deflection as well as in the perpendicular surface to this plane. The obtained expressions are compared to precise numerical ray-tracing calculations through typical field distributions. (orig.).

  13. A convenient look-up-table based method for the compensation of non-linear error in digital fringe projection

    Directory of Open Access Journals (Sweden)

    Chen Xiong

    2016-01-01

    Full Text Available Although the structured light system that uses digital fringe projection has been widely implemented in three-dimensional surface profile measurement, the measurement system is susceptible to non-linear error. In this work, we propose a convenient look-up-table-based (LUT-based method to compensate for the non-linear error in captured fringe patterns. Without extra calibration, this LUT-based method completely utilizes the captured fringe pattern by recording the full-field differences. Then, a phase compensation map is established to revise the measured phase. Experimental results demonstrate that this method works effectively.

  14. Formation of uniform fringe pattern free from diffraction noise at LDA measurement volume using holographic imaging configuration

    Science.gov (United States)

    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.

  15. Optical-Based Sensors for Monitoring Corrosion of Reinforcement Rebar via an Etched Cladding Bragg Grating

    Directory of Open Access Journals (Sweden)

    Faisal Rafiq Mahamd Adikan

    2012-11-01

    Full Text Available In this paper, we present the development and testing of an optical-based sensor for monitoring the corrosion of reinforcement rebar. The testing was carried out using an 80% etched-cladding Fibre Bragg grating sensor to monitor the production of corrosion waste in a localized region of the rebar. Progression of corrosion can be sensed by observing the reflected wavelength shift of the FBG sensor. With the presence of corrosion, the etched-FBG reflected spectrum was shifted by 1.0 nm. In addition, with an increase in fringe pattern and continuously, step-like drop in power of the Bragg reflected spectrum was also displayed.

  16. Impact of land-use change and hard structures on the evolution of fringing marsh shorelines

    Science.gov (United States)

    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

  17. Time-domain fiber loop ringdown sensor and sensor network

    Science.gov (United States)

    Kaya, Malik

    Optical fibers have been mostly used in fiber optic communications, imaging optics, sensing technology, etc. Fiber optic sensors have gained increasing attention for scientific and structural health monitoring (SHM) applications. In this study, fiber loop ringdown (FLRD) sensors were fabricated for scientific, SHM, and sensor networking applications. FLRD biosensors were fabricated for both bulk refractive index (RI)- and surface RI-based DNA sensing and one type of bacteria sensing. Furthermore, the effect of glucose oxidase (GOD) immobilization at the sensor head on sensor performance was evaluated for both glucose and synthetic urine solutions with glucose concentration between 0.1% and 10%. Detection sensitivities of the glucose sensors were achieved as low as 0.05%. For chemical sensing, heavy water, ranging from 97% to 10%, and several elemental solutions were monitored by using the FLRD chemical sensors. Bulk index-based FLRD sensing showed that trace elements can be detected in deionized water. For physical sensing, water and cracking sensors were fabricated and embedded into concrete. A partially-etched single-mode fiber (SMF) was embedded into a concrete bar for water monitoring while a bare SMF without any treatment was directly embedded into another concrete bar for monitoring cracks. Furthermore, detection sensitivities of water and crack sensors were investigated as 10 ml water and 0.5 mm surface crack width, respectively. Additionally fiber loop ringdown-fiber Bragg grating temperature sensors were developed in the laboratory; two sensor units for water, crack, and temperature sensing were deployed into a concrete cube in a US Department of Energy test bed (Miami, FL). Multi-sensor applications in a real concrete structure were accomplished by testing the six FLRD sensors. As a final stage, a sensor network was assembled by multiplexing two or three FLRD sensors in series and parallel. Additionally, two FLRD sensors were combined in series and

  18. Great prospects for fiber optics sensors

    Science.gov (United States)

    Hansen, T. E.

    1983-10-01

    Fiber optic sensors provide noise immunity and galvanic insulation at the measurement point. Interest in such sensors is increasing for these reasons. In the United States sales are expected to increase from 12 million dollars in 1981 to 180 million in 1991. Interferometric sensors based on single modus fibers deliver extremely high sensitivity, while sensors based on multi-modus fibers are more easily manufactured. The fiber optic sensors which are available today are based on point measurements. Development of fiber optic sensors in Norway is being carried out at the Central institute and has resulted in the development of medical manometers which are now undergoing clinical testing.

  19. Multiparametric methane sensor for environmental monitoring

    Science.gov (United States)

    Borecki, M.; Duk, M.; Kociubiński, A.; Korwin-Pawlowski, M. L.

    2016-12-01

    Today, methane sensors find applications mostly in safety alarm installations, gas parameters detection and air pollution classification. Such sensors and sensors elements exists for industry and home use. Under development area of methane sensors application is dedicated to ground gases monitoring. Proper monitoring of soil gases requires reliable and maintenance-free semi-constant and longtime examination at relatively low cost of equipment. The sensors for soil monitoring have to work on soil probe. Therefore, sensor is exposed to environment conditions, as a wide range of temperatures and a full scale of humidity changes, as well as rain, snow and wind, that are not specified for classical methane sensors. Development of such sensor is presented in this paper. The presented sensor construction consists of five commercial non dispersive infra-red (NDIR) methane sensing units, a set of temperature and humidity sensing units, a gas chamber equipped with a micro-fan, automated gas valves and also a microcontroller that controls the measuring procedure. The electronics part of sensor was installed into customized 3D printed housing equipped with self-developed gas valves. The main development of proposed sensor is on the side of experimental evaluation of construction reliability and results of data processing included safety procedures and function for hardware error correction. Redundant methane sensor units are used providing measurement error correction as well as improved measurement accuracy. The humidity and temperature sensors are used for internal compensation of methane measurements as well as for cutting-off the sensor from the environment when the conditions exceed allowable parameters. Results obtained during environment sensing prove that the gas concentration readings are not sensitive to gas chamber vertical or horizontal position. It is important as vertical sensor installation on soil probe is simpler that horizontal one. Data acquired during six

  20. Fringe structures and tunable bandgap width of 2D boron nitride nanosheets

    Directory of Open Access Journals (Sweden)

    Peter Feng

    2014-07-01

    Full Text Available 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.

  1. EFFECT OF DIGITAL FRINGE PROJECTION PARAMETERS ON 3D RECONSTRUCTION ACCURACY

    Directory of Open Access Journals (Sweden)

    A. Babaei

    2013-09-01

    This paper aims to evaluate different parameters which affect the accuracy of the final results. For this purpose, some test were designed and implemented. These tests assess the number of phase shifts, spatial frequency of the fringe pattern, light condition, noise level of images, and the color and material of target objects on the quality of resulted phase map. The evaluation results demonstrate that digital fringe projection method is capable of obtaining depth map of complicated object with high accuracy. The contrast test results showed that this method is able to work under different ambient light condition; although at places with high light condition will not work properly. The results of implementation on different objects with various materials, color and shapes demonstrate the high capability of this method of 3D reconstruction.

  2. Axial loading verification method for small bones using carrier fringes in speckle pattern interferometry

    Science.gov (United States)

    Dávila, A.; Márquez, S.; Landgrave, E.; Vázquez, Z.; Vera, K.; Caudillo, C.

    2015-06-01

    A computerized system for real-time displacement visualization using carrier fringes in an electronic speckle in-plane sensitive interferometer allows force calibration for micro-displacement analysis of rat bones and verification of axial loading conditions. Once the force has been calibrated and the load is applied along the bone axis, the difference-of-phase method is used to obtain the phase map, which after phase unwrapping, allows the evaluation of the displacements produced by the bone deformation. The proposed method avoids common loading mistakes using first carrier fringes to assure that the loads are within the measuring capabilities of the in-plane interferometer and the Carré phase-stepping method to compensate for linear phase step miscalibration. The experimental results obtained with the calibration of loading forces and axial loading verification show the advantages of the system proposed here over a system which uses a cantilever configuration to make a similar bone deformation analysis.

  3. Three-dimensional surface inspection for semiconductor components with fringe projection profilometry

    Science.gov (United States)

    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.

  4. Numerous possible oriented partial differential equations and investigation of their performance for optical interferometry fringes denoising.

    Science.gov (United States)

    Mi, Qinghua; Yan, Si; Tang, Chen

    2013-12-10

    Filtering methods based on oriented partial differential equations (OPDEs) have been demonstrated as a powerful tool for denoising while preserving all fringes. In this paper, we first briefly review the existing OPDEs and then derive numerous possible OPDE filtering models based on the variational methods. These models include a class of new single OPDE models, a class of new selective OPDE models, a class of new coupled OPDEs, and a class of new double OPDEs. We also investigate the performance of main OPDE models, including the choices of parameters and the influences of fringe orientation and diffusion control function on filtering results via our extensive experiments. Finally, we summarize the performance of these OPDEs.

  5. Visual modeling of laser Doppler anemometer signals by moiré fringes.

    Science.gov (United States)

    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.

  6. Fourier analysis of RGB fringe-projection profilometry and robust phase-demodulation methods against crosstalk distortion

    CERN Document Server

    Padilla, Moises; Garnica, Guillermo

    2016-01-01

    In this paper we apply the frequency transfer function (FTF) formalism to analyze the red, green and blue (RGB) phase-shifting fringe-projection profilometry technique. The phase-shifted fringe patterns in RGB fringe projection are typically corrupted by crosstalk because the sensitivity curves of most projection-recording systems overlap. Crosstalk distortion needs to be compensated in order to obtain high quality measurements. We study phase-demodulation methods for null/mild, moderate, and severe levels of RGB crosstalk. For null/mild crosstalk, we can estimate the searched phase-map using Bruning's 3-step phase-shifting algorithm (PSA). For moderate crosstalk, the RGB recorded data is usually preprocessed before feeding it into Bruning's PSA; alternatively, in this paper we propose a computationally more efficient approach, which combines crosstalk compensation and phase-demodulation into a single process. For severe RGB crosstalk, we expect non-sinusoidal fringes' profiles (distorting harmonics) and sign...

  7. Sensor Compendium

    CERN Document Server

    Artuso, M; Bolla, G; Bortoletto, D; Caberera, B; Carlstrom, J E; Chang, C L; Cooper, W; Da Via, C; Demarteau, M; Fast, J; Frisch, H; Garcia-Sciveres, M; Golwala, S; Haber, C; Hall, J; Hoppe, E; Irwin, K D; Kagan, H; Kenney, C; Lee, A T; Lynn, D; Orrell, J; Pyle, M; Rusack, R; Sadrozinski, H; Sanchez, M C; Seiden, A; Trischuk, W; Vavra, J; Wetstein, M; Zhu, R-Y

    2013-01-01

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future ...

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

    Science.gov (United States)

    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.

  9. Displaced workers and employer-provided health insurance: evidence of a wage/fringe benefit tradeoff?

    Science.gov (United States)

    Simon, K I

    2001-01-01

    Job changes that result from plant closings and mass layoffs provide an opportunity to see how workers respond to an employment shock that is arguably exogenous to individual productivity. Comparing compensation packages of displaced workers on their old and new jobs is a potentially promising method to infer a tradeoff between wages and non-wage benefits. Although displaced worker data overcomes many of the pitfalls to estimating wage/fringe tradeoffs by controlling for time-invariant unobserved productivity, time-varying unobservables could still bias estimates. In this analysis, I investigate the compensating wage differential for one particularly valuable benefit, employer-provided health insurance. I find that even after controlling for an extensive set of productivity factors, I obtain results indicating a wrong-signed tradeoff. Those who lose health insurance through the job change also lose wages relative to other displaced workers, while those who gain health insurance also gain in wages. Individuals expected to incur higher health care costs (older workers and workers who are likely to buy family coverage) do not experience steeper wage/health insurance tradeoffs as would be expected if employers were able to pass health care costs on to workers according to individual costs. Although this exercise fails to isolate a wage/fringe tradeoff, the strong correlation between changes in wages and changes in fringe benefits has important implications for public policy towards displaced workers. Further research is needed to understand the true magnitude and distribution of the costs of job displacement taking changes in fringe benefits into account.

  10. Performance of the LINC NIRVANA fringe and flexure tracker at delivery

    Science.gov (United States)

    Horrobin, Matthew; Eckart, Andreas; Beckmann, Udo; Connot, Claus; Dierkes, Jens; Lindhorst, Bettina; Nußbaum, Edmund; Rost, Steffen; Smajić, Semir; Straubmeier, Christian; Wank, Imke; Bertram, Thomas; Pott, Jörg-Uwe

    2014-07-01

    The LINC-NIRVANA Fringe and Flexure Tracking System has nearly completed assembly in the lab in Cologne, and will soon be ready for shipment and integration into the full LINC-NIRVANA system at MPIA Heidelberg. This paper provides an overview of the final assembly and testing phase in Cologne, concentrating on those aspects that directly affect instrument performance, including the detector performance and stability of the detector positioning system.

  11. Using a Monte-Carlo-based approach to evaluate the uncertainty on fringe projection technique

    CERN Document Server

    Molimard, Jérôme

    2013-01-01

    A complete uncertainty analysis on a given fringe projection set-up has been performed using Monte-Carlo approach. In particular the calibration procedure is taken into account. Two applications are given: at a macroscopic scale, phase noise is predominant whilst at microscopic scale, both phase noise and calibration errors are important. Finally, uncertainty found at macroscopic scale is close to some experimental tests (~100 {\\mu}m).

  12. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

    Science.gov (United States)

    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.

  13. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

    Science.gov (United States)

    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.

  14. Wind Sensor

    OpenAIRE

    Li, Jiaoyang; Ni, Jiqin

    2014-01-01

    Wind measurement is needed in many practical and scientific research situations. Some specific applications require to precisely measuring both wind direction and wind speed at the same time. Current commercial sensors for wind direction and wind speed measurement usually use ultrasonic technology and the sensors are very expensive (> $1500). In addition, the sensors are large in dimension and cannot measure airflow patterns in high spatial resolution. Therefore new and low cost wind speed an...

  15. Patch-wise denoising of phase fringe patterns based on matrix enhancement

    Science.gov (United States)

    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.

  16. A Flexible Fringe Projection Vision System with Extended Mathematical Model for Accurate Three-Dimensional Measurement

    Directory of Open Access Journals (Sweden)

    Suzhi Xiao

    2016-04-01

    Full Text Available In order to acquire an accurate three-dimensional (3D measurement, the traditional fringe projection technique applies complex and laborious procedures to compensate for the errors that exist in the vision system. However, the error sources in the vision system are very complex, such as lens distortion, lens defocus, and fringe pattern nonsinusoidality. Some errors cannot even be explained or rendered with clear expressions and are difficult to compensate directly as a result. In this paper, an approach is proposed that avoids the complex and laborious compensation procedure for error sources but still promises accurate 3D measurement. It is realized by the mathematical model extension technique. The parameters of the extended mathematical model for the ’phase to 3D coordinates transformation’ are derived using the least-squares parameter estimation algorithm. In addition, a phase-coding method based on a frequency analysis is proposed for the absolute phase map retrieval to spatially isolated objects. The results demonstrate the validity and the accuracy of the proposed flexible fringe projection vision system on spatially continuous and discontinuous objects for 3D measurement.

  17. Status monitoring and health assessment of Luhuitou fringing reef of Sanya,Hainan, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiaomin; SHI Qi; CHEN Gang; FONG T C W; WONG D C C; HUANG Hui; WANG Hankui; ZHAO Meixia

    2006-01-01

    The monitoring survey and health assessment for benthic community were carried out in Luhuitou fringing reef of Sanya, Hainan, China in 2002. Monitoring survey included manta tow, line intercept transect, video transect and digital photograph. The mean live coral cover was 23.40%. Comparison of used monitoring methods showed that video transect can replace line intercept transect, and 50 m transect is better than 20 m transect in uneven coral region. Survey data and comparison with previous research work showed that Luhuitou fringing reef has been damaged severely and has a general declining trend with live coral cover from about 85% in the 1960s down to 20% in 2004,but it still has quite high biodiversity and therefore has special protection value. Main factors of Luhuitou fringing reef declining were human activities including reef rock digging and curios collecting, destructive fishing, sediment and pollutant from coastal land, and recent marine aquaculture. Only strengthening integrated management can reach improvement and restoration of Luhuitou declining coral reef ecosystem.

  18. Novel Method of Detecting Movement of the Interference Fringes Using One-Dimensional PSD

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2015-06-01

    Full Text Available In this paper, a method of using a one-dimensional position-sensitive detector (PSD by replacing charge-coupled device (CCD to measure the movement of the interference fringes is presented first, and its feasibility is demonstrated through an experimental setup based on the principle of centroid detection. Firstly, the centroid position of the interference fringes in a fiber Mach-Zehnder (M-Z interferometer is solved in theory, showing it has a higher resolution and sensitivity. According to the physical characteristics and principles of PSD, a simulation of the interference fringe’s phase difference in fiber M-Z interferometers and PSD output is carried out. Comparing the simulation results with the relationship between phase differences and centroid positions in fiber M-Z interferometers, the conclusion that the output of interference fringes by PSD is still the centroid position is obtained. Based on massive measurements, the best resolution of the system is achieved with 5.15, 625 μm. Finally, the detection system is evaluated through setup error analysis and an ultra-narrow-band filter structure. The filter structure is configured with a one-dimensional photonic crystal containing positive and negative refraction material, which can eliminate background light in the PSD detection experiment. This detection system has a simple structure, good stability, high precision and easily performs remote measurements, which makes it potentially useful in material small deformation tests, refractivity measurements of optical media and optical wave front detection.

  19. A phase retrieval algorithm based on color-frequency encoding for fringe reflection technique

    Science.gov (United States)

    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.

  20. Experimental and Numerical Studies on Wave Breaking Characteristics over a Fringing Reef under Monochromatic Wave Conditions

    Directory of Open Access Journals (Sweden)

    Jong-In Lee

    2014-01-01

    Full Text Available Fringing reefs play an important role in protecting the coastal area by inducing wave breaking and wave energy dissipation. However, modeling of wave transformation and energy dissipation on this topography is still difficult due to the unique structure. In the present study, two-dimensional laboratory experiments were conducted to investigate the cross-shore variations of wave transformation, setup, and breaking phenomena over an idealized fringing reef with the 1/40 reef slope and to verify the Boussinesq model under monochromatic wave conditions. One-layer and two-layer model configurations of the Boussinesq model were used to figure out the model capability. Both models predicted well (r2>0.8 the cross-shore variation of the wave heights, crests, troughs, and setups when the nonlinearity is not too high (A0/h0<0.07 in this study. However, as the wave nonlinearity and steepness increase, the one-layer model showed problems in prediction and stability due to the error on the vertical profile of fluid velocity. The results in this study revealed that one-layer model is not suitable in the highly nonlinear wave condition over a fringing reef bathymetry. This data set can contribute to the numerical model verification.

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

    Science.gov (United States)

    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.

  2. 干涉条纹计数器的研制%Study of interference fringe counter

    Institute of Scientific and Technical Information of China (English)

    王守权; 张绍良; 张薇

    2000-01-01

    A new interference fringe counter on the basis of photoelectric principles which converts optical signals on ground glass into electrical ones is introduced. Some interference elements of counting and the means to eliminate the interference are analyzed. After data processing and calculating, number of interference fringes is displayed by the counter. This meter is automatic and the data processed are more precise than those of the existing interference fringe counter.%设计了一种新的干涉条纹计数仪,分析了对计数进行干扰的几种因素及排除的方法。该设计应用光电变换原理,把毛玻璃上的光信号转换成电信号,再经适当处理,把干涉条纹变化的数量用计数器记录并显示出来,比常规的干涉条纹计数手段更加自动化,数据更加准确直观。

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

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi, D. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Universita Politecnica delle Marche, via Brecce Bianche, 60131 Ancona (Italy); INFN, Section of Perugia (Italy)], E-mail: d.rinaldi@univpm.it; Pietroni, P. [Dipartimento di Meccanica, Universita Politecnica delle Marche, via Brecce Bianche, 60131 Ancona (Italy); Davi, F. [Dipartimento di Architettura, Costruzioni e Strutture, Universita Politecnica delle Marche, via Brecce Bianche, 60131 Ancona (Italy)

    2009-05-21

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

  4. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  5. Sensor web

    Science.gov (United States)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  6. Novel “turn on” fluorescent sensors based on anthracene and carbazone units for Cu (II) ion in CH{sub 3}CN–H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Serkan, E-mail: serdemir82@gmail.com; Malkondu, Sait

    2015-02-15

    Two novel anthracene-based receptors containing Schiff base and urea groups (AOC and ATC) were synthesized in one step and full characterized. The optical properties of receptors AOC and ATC towards metal ions were investigated by UV–visible and fluorescence spectroscopy. It was found that both receptors AOC and ATC show highly selectivity towards Cu{sup 2+} over other 17 metal ions in CH{sub 3}CN–H{sub 2}O (9/1, v/v). - Highlights: • Novel fluorescent sensors based on anthracene and carbazide AOC and ATC were synthesized. • The optical properties of AOC and ATC were observed by UV–visible and fluorescence spectroscopy. • AOC and ATC showed highly selective and sensitive to Cu{sup 2+} over other 17 metal ions.

  7. Improved 3D displacement measurements method and calibration of a combined fringe projection and 2D-DIC system

    Science.gov (United States)

    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.

  8. 3D phase-shifting fringe projection system on the basis of a tailored free-form mirror.

    Science.gov (United States)

    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.

  9. Exact modeling of lineshape and wavenumber variations for off-axis detectors in Fourier transform spectrometers (FTS) sensor systems

    Science.gov (United States)

    Niple, E.; Pires, A.; Poultney, S. K.

    1983-01-01

    The utilization of detector arrays in the focal planes of FTS sensor systems allows simultaneous spectral and spatial measurements. However, spectral lineshapes and wavenumber locations depend upon the size and location of the detector elements with respect to the Haidinger fringe pattern of the FTS sensor. These spectral distortions can be generalized as a shift and shape change of the FTS sensor lineshape. Depending on the distortions that can be tolerated, a degree of field-widening can be obtained for a given Haidinger fringe pattern. An exact model for predicting the FTS lineshape distortions is presented. The model is applied to several contemporary applications in order to quantify the magnitude of distortions to be expected.

  10. Simulating the evolution of an ethanol and gasoline source zone within the capillary fringe.

    Science.gov (United States)

    Yu, Soonyoung; Freitas, Juliana G; Unger, Andre J A; Barker, James F; Chatzis, John

    2009-02-27

    Blending of ethanol into gasoline as a fuel oxygenate has created the scenario where inadvertent releases of E95 into soil previously contaminated by gasoline may remobilize these pre-existing NAPLs and lead to higher dissolved hydrocarbon (BTEX) concentrations in groundwater. We contribute to the development of a risk-based corrective action framework addressing this issue by conducting two laboratory experiments involving the release of ethanol into a gasoline source zone established in the capillary fringe. We then develop and apply the numerical model CompFlow Bio to replicate three specific experimental observations: (1) depression of the capillary fringe by the addition of the gasoline fuel mixture due to a reduction in the surface tension between the gas and liquid phases, (2) further depression of the capillary fringe by the addition of ethanol, and (3) remobilization of the gasoline fuel mixture LNAPL source zone due to the cosolvent behaviour of ethanol in the presence of an aqueous phase, as well as a reduction in the interfacial tension between the aqueous/non-aqueous phases due to ethanol. While the simulated collapse of the capillary fringe was not as extensive as that which was observed, the simulated and observed remobilized non-aqueous phase distributions were in agreement following ethanol injection. Specifically, injection of ethanol caused the non-aqueous phase to advect downwards toward the water table as the capillary fringe continued to collapse, finally collecting on top of the water table in a significantly reduced area exhibiting higher saturations than observed prior to ethanol injection. Surprisingly, the simulated ethanol and gasoline aqueous phase plumes were uniform despite the redistribution of the source zone. Dissolution of gasoline into the aqueous phase was dramatically increased due to the cosolvency effect of ethanol on the non-aqueous phase source zone. We advocate further experimental studies focusing on eliminating data gaps

  11. Nonlinear analysis of cylindrical capacitive sensor used for measuring high precision spindle rotation errors

    Science.gov (United States)

    Xiang, Kui; Wang, Wen; Zhang, Min; Lu, Keqing; Fan, Zongwei; Chen, Zichen

    2015-02-01

    A novel cylindrical capacitive sensor (CCS) with differential, symmetrical and integrated structure was proposed to measure multi-degree-of-freedom rotation errors of high precision spindle simultaneously and to reduce impacts of multiple sensors installation errors on the measurement accuracy. The nonlinear relationship between the output capacitance of CCS and the radial gap was derived using the capacitance formula and was quantitatively analyzed. It was found through analysis that the thickness of curved electrode plates led to the existence of fringe effect. The influence of the fringe effect on the output capacitance was investigated through FEM simulation. It was found through analysis and simulation that the CCS could be optimized to improve the measurement accuracy.

  12. Multi-resolution optical 3D sensor

    Science.gov (United States)

    Kühmstedt, Peter; Heinze, Matthias; Schmidt, Ingo; Breitbarth, Martin; Notni, Gunther

    2007-06-01

    A new multi resolution self calibrating optical 3D measurement system using fringe projection technique named "kolibri FLEX multi" will be presented. It can be utilised to acquire the all around shape of small to medium objects, simultaneously. The basic measurement principle is the phasogrammetric approach /1,2,3/ in combination with the method of virtual landmarks for the merging of the 3D single views. The system consists in minimum of two fringe projection sensors. The sensors are mounted on a rotation stage illuminating the object from different directions. The measurement fields of the sensors can be chosen different, here as an example 40mm and 180mm in diameter. In the measurement the object can be scanned at the same time with these two resolutions. Using the method of virtual landmarks both point clouds are calculated within the same world coordinate system resulting in a common 3D-point cloud. The final point cloud includes the overview of the object with low point density (wide field) and a region with high point density (focussed view) at the same time. The advantage of the new method is the possibility to measure with different resolutions at the same object region without any mechanical changes in the system or data post processing. Typical parameters of the system are: the measurement time is 2min for 12 images and the measurement accuracy is below 3μm up to 10 μm. The flexibility makes the measurement system useful for a wide range of applications such as quality control, rapid prototyping, design and CAD/CAM which will be shown in the paper.

  13. Chemical sensors

    Science.gov (United States)

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  14. Small, Inexpensive Combined NOx Sensor and O2 Sensor

    Energy Technology Data Exchange (ETDEWEB)

    W. N. Lawless; C. F. Clark, Jr.

    2008-09-08

    electronic control units were designed and built. One control unit provides independent constant voltages to the NOx and oxygen sensors and reads the current from them (that is, detects the amount of test gas present). The second controller holds the fully-assembled sensor at the desired operating temperature and controllably pumps excess oxygen from the test chamber. While the development of the sensor body was a complete success, the development of the packaging was only partially successful. All of the basic principles were demonstrated, but the packaging was too complex to optimize the operation within the resources of the program. Thus, no fully-assembled sensors were sent to outside labs for testing of cross-sensitivities, response times, etc. Near the end of the program, Sensata Technologies of Attleboro, MA tested the sensor bodies and confirmed the CeramPhysics measurements as indicated in the following attached letter. Sensata was in the process of designing their own packaging for the sensor and performing cross-sensitivity tests when they stopped all sensor development work due to the automotive industry downturn. Recently Ceramatec Inc. of Salt Lake City has expressed an interest in testing the sensor, and other licensing opportunities are being pursued.

  15. Pathogen Sensors

    Directory of Open Access Journals (Sweden)

    Joseph Irudayaraj

    2009-10-01

    Full Text Available The development of sensors for detecting foodborne pathogens has been motivated by the need to produce safe foods and to provide better healthcare. However, in the more recent times, these needs have been expanded to encompass issues relating to biosecurity, detection of plant and soil pathogens, microbial communities, and the environment. The range of technologies that currently flood the sensor market encompass PCR and microarray-based methods, an assortment of optical sensors (including bioluminescence and fluorescence, in addition to biosensor-based approaches that include piezoelectric, potentiometric, amperometric, and conductometric sensors to name a few. More recently, nanosensors have come into limelight, as a more sensitive and portable alternative, with some commercial success. However, key issues affecting the sensor community is the lack of standardization of the testing protocols and portability, among other desirable elements, which include timeliness, cost-effectiveness, user-friendliness, sensitivity and specificity. [...

  16. Smart Sensors

    Science.gov (United States)

    Corsi, C.

    2007-01-01

    The term "Smart Sensors" refers to sensors which contain both sensing and signal processing capabilities with objectives ranging from simple viewing to sophisticated remote sensing, surveillance, search/track, weapon guidance, robotics, perceptronics and intelligence applications. Recently this approach is achieving higher goals by a new and revolutionary sensors concept which introduced inside the sensor some of the basic functions of living eyes, such as dynamic stare, non-uniformity compensation, spatial and temporal filtering. New objectives and requirements are presented for this type of new infrared smart sensor systems. This paper is concerned with the front end of FPA microbolometers processing, namely, the enhancement of target-to-noise ratio by background clutter suppression and the improvement in target detection by "smart" and pattern correlation thresholding.

  17. Development of compact cold-atom sensors for inertial navigation

    CERN Document Server

    Battelier, B; Fouché, L; Chichet, L; Antoni-Micollier, L; Porte, H; Napolitano, F; Lautier, J; Landragin, A; Bouyer, P

    2016-01-01

    Inertial sensors based on cold atom interferometry exhibit many interesting features for applications related to inertial navigation, particularly in terms of sensitivity and long-term stability. However, at present the typical atom interferometer is still very much an experiment---consisting of a bulky, static apparatus with a limited dynamic range and high sensitivity to environmental effects. To be compliant with mobile applications further development is needed. In this work, we present a compact and mobile experiment, which we recently used to achieve the first inertial measurements with an atomic accelerometer onboard an aircraft. By integrating classical inertial sensors into our apparatus, we are able to operate the atomic sensor well beyond its standard operating range, corresponding to half of an interference fringe. We report atom-based acceleration measurements along both the horizontal and vertical axes of the aircraft with one-shot sensitivities of $2.3 \\times 10^{-4}\\,g$ over a range of $\\sim 0...

  18. Automotive sensors

    Science.gov (United States)

    Marek, Jiri; Illing, Matthias

    2003-01-01

    Sensors are an essential component of most electronic systems in the car. They deliver input parameters for comfort features, engine and emission control as well as for the active and passive safety systems. New technologies such as silicon micromachining play an important role for the introduction of these sensors in all vehicle classes. The importance and use of these sensor technologies in today"s automotive applications will be shown in this article. Finally an outlook on important current developments and new functions in the car will be given.

  19. Piezoceramic Sensors

    CERN Document Server

    Sharapov, Valeriy

    2011-01-01

    This book presents the latest and complete information about various types of piezosensors. A sensor is a converter of the measured physical size to an electric signal. Piezoelectric transducers and sensors are based on piezoelectric effects. They have proven to be versatile tools for the measurement of various processes. They are used for quality assurance, process control and for research and development in many different industries. In each area of application specific requirements to the parameters of transducers and sensors are developed. This book presents the fundamentals, technical des

  20. Lateral ink mobility and fringe field effects across the porous matrix of an electrophoretic display

    Science.gov (United States)

    Li Tsui, Kelly; Ahumada, Manuel; Bryning, Mateusz; Hartono, Michelle; Lee, Sang-Joon J.

    2013-03-01

    This investigation studies fringe field between laterally adjacent electrodes in a reverse-emulsion electrophoretic display (REED). The display consists of a nanodroplet ink and a porous matrix that serves as the "paper" between planar electrodes. One relative advantage of this type of electronic paper display is that it can be produced with lowcost materials and manufacturing processes. A concern for image resolution, however, is the fringe field effect that occurs in the gaps between neighboring electrodes. Ideally the dye-containing nanodroplets in the ink move in a direction that is strictly perpendicular to the opposing pairs of electrodes. However, nanodroplet saturation and potential gradients from neighboring electrodes may result in lateral displacement of the nanodroplets as well. Accordingly, this study examines how fringe field between neighboring electrodes is affected by lateral spacing and applied voltage. Transient and steady-state effects were studied by fabricating and testing devices that were patterned with different lateral spacing between electrodes, and switching under different voltage levels. Relative luminance was extracted from digital microscope images, captured in the vicinity between neighboring electrodes. Measurements were recorded for electrode spacing of 20 μm, 40 μm, 60 μm, and 80 μm with devices switched at ±1.5 V and ±2.5 V. Gradients in luminance overlapped at lateral distances below 60 μm, and became distinct for left and right electrodes spaced by at least 80 μm. Higher applied voltage resulted in steeper transition between light and dark states, but exhibited distortion at electrode edges.

  1. The effects of the solar radiation pressure on the F-ring particles

    Science.gov (United States)

    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

  2. Vibrissa Sensor

    Science.gov (United States)

    2016-09-30

    Docket No. 300119 1 of 11 VIBRISSA SENSOR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention provides a... measured as strain. [0009] Thus, there is a need for a sensor utilizing a vibrissa that can detect dynamic and high frequency movement of the

  3. Carbon Nanostructure Examined by Lattice Fringe Analysis of High Resolution Transmission Electron Microscopy Images

    Science.gov (United States)

    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.

  4. Research and development of fringe projection-based methods in 3D shape reconstruction

    Institute of Scientific and Technical Information of China (English)

    WU Lu-shen; PENG Qing-jin

    2006-01-01

    This paper discusses current research and development of fringe projection-based techniques. A system based on Fourier transform profilometry (FTP) is proposed for three-dimensional (3D) shape recovery. The system improves the method of phase unwrapping to gain accurate 3D shapes of objects. The method uses a region-growing algorithm for the path prediction guided by the quality map to increase the recovering accuracy and provides a fast and simple tool for 3D shape recovery. The shape measurement and data recovery are integrated to offer a new method of 3D modelling. Examples are presented to verify the feasibility of the proposed method.

  5. Fringe View: Problems and Construction of Human Settlement Environment for Village-in-City

    Institute of Scientific and Technical Information of China (English)

    Mo Chuangrong; Li Xia; Wang Shugong; Chen Xingeng

    2005-01-01

    The construction of human settlement environment is one of the important contents in the domain of sustainable development. We try to annotate human settlement environment for "villagein-city" from the angle of fringe view. According to the macro-system thought of human setdement environment science, the evolvement, which can be generalized into four phases, connotation and problems (including social, economic, and environmental problems) of "village-in-city" are discussed primarily in this paper. Some domestic and international researches and practices are also summarized and assessed in the paper. Based on the analysis, some appropriate dues and suggestions for the construction of "village-in-city" have been put forward.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Fringe jump analysis and implementation of polarimetry on the ASDEX Upgrade DCN interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Mlynek, A., E-mail: amlynek@ipp.mpg.de; Casali, L.; Eixenberger, H. [Max-Planck-Institute for Plasma Physics, Garching 85748 (Germany); Ford, O. [Max-Planck-Institute for Plasma Physics, Greifswald 17491 (Germany)

    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.

  8. Sinusoidal phase-modulating fiber-optic interferometer fringe with a feedback control system.

    Science.gov (United States)

    Lv, Changrong; Duan, Fajie; Bo, En; Duan, Xiaojie; Feng, Fan; Fu, Xiao

    2014-09-20

    A displacement measurement system using a fiber-optic interferometer fringe projector with a feedback control system is presented and demonstrated. The system utilizes the integrating bucket method to detect the desired phase or the displacement and Fresnel reflection signal to realize measurement of the disturbance and feed it back to the modulated signal of the laser at the same time. The continuous signal truly reflects the error information, as the output light and reflected light share the same optical path. Practical experiments validate the feasibility of this method.

  9. Fringe jump analysis and implementation of polarimetry on the ASDEX Upgrade DCN interferometer.

    Science.gov (United States)

    Mlynek, A; Casali, L; Ford, O; Eixenberger, H

    2014-11-01

    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.

  10. First On-Sky Fringes with an Up-Conversion Interferometer Tested on a Telescope Array.

    Science.gov (United States)

    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. Fringe Field Effects on Bending Magnets, Derived for TRANSPORT/TURTLE

    CERN Document Server

    Blitz, Sam

    2013-01-01

    A realistic magnetic dipole has complex effects on a charged particle near the entrance and exit of the magnet, even with a constant and uniform magnetic field deep within the interior of the magnet. To satisfy Maxwell's equations, the field lines near either end of a realistic magnet are significantly more complicated, yielding non-trivial forces. The effects of this fringe field are calculated to first order, applying both the paraxial and thin lens approximations. We find that, in addition to zeroth order effects, the position of a particle directly impacts the forces in the horizontal and vertical directions.

  12. Two-dimensional phase unwrapping algorithms for fringe pattern analysis: a comparison study

    Science.gov (United States)

    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.

  13. Image aberrations in optical three-dimensional measurement systems with fringe projection.

    Science.gov (United States)

    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.

  14. A 3D Optical Surface Profilometer Using a Dual-Frequency Liquid Crystal-Based Dynamic Fringe Pattern Generator

    Directory of Open Access Journals (Sweden)

    Kyung-Il Joo

    2016-10-01

    Full Text Available 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.

  15. High-speed scanning stroboscopic fringe-pattern projection technology for three-dimensional shape precision measurement.

    Science.gov (United States)

    Yang, Guowei; Sun, Changku; Wang, Peng; Xu, Yixin

    2014-01-10

    A high-speed scanning stroboscopic fringe-pattern projection system is designed. A high-speed rotating polygon mirror and a line-structured laser cooperate to produce stable and unambiguous stroboscopic fringe patterns. The system combines the rapidity of the grating projection with the high accuracy of the line-structured laser light source. The fringe patterns have fast frame rate, great density, high precision, and high brightness, with convenience and accuracy in adjusting brightness, frequency, linewidth, and the amount of phase shift. The characteristics and the stability of this system are verified by experiments. Experimental results show that the finest linewidth can reach 40 μm and that the minimum fringe cycle is 80 μm. Circuit modulation makes the light source system flexibly adjustable, easy to control in real time, and convenient to project various fringe patterns. Combined with different light intensity adjustment algorithms and 3D computation models, the 3D topography with high accuracy can be obtained for objects measured under different environments or objects with different sizes, morphologies, and optical properties. The proposed system shows a broad application prospect for fast 3D shape precision measurements, particularly in the industrial field of 3D online detection for precision devices.

  16. Vibration sensors

    Science.gov (United States)

    Gupta, Amita; Singh, Ranvir; Ahmad, Amir; Kumar, Mahesh

    2003-10-01

    Today, vibration sensors with low and medium sensitivities are in great demand. Their applications include robotics, navigation, machine vibration monitoring, isolation of precision equipment & activation of safety systems e.g. airbags in automobiles. Vibration sensors have been developed at SSPL, using silicon micromachining to sense vibrations in a system in the 30 - 200 Hz frequency band. The sensing element in the silicon vibration sensor is a seismic mass suspended by thin silicon hinges mounted on a metallized glass plate forming a parallel plate capacitor. The movement of the seismic mass along the vertical axis is monitored to sense vibrations. This is obtained by measuring the change in capacitance. The movable plate of the parallel plate capacitor is formed by a block connected to a surrounding frame by four cantilever beams located on sides or corners of the seismic mass. This element is fabricated by silicon micromachining. Several sensors in the chip sizes 1.6 cm x 1.6 cm, 1 cm x 1 cm and 0.7 cm x 0.7 cm have been fabricated. Work done on these sensors, techniques used in processing and silicon to glass bonding are presented in the paper. Performance evaluation of these sensors is also discussed.

  17. An ontology for sensor networks

    Science.gov (United States)

    Compton, Michael; Neuhaus, Holger; Bermudez, Luis; Cox, Simon

    2010-05-01

    Sensors and networks of sensors are important ways of monitoring and digitizing reality. As the number and size of sensor networks grows, so too does the amount of data collected. Users of such networks typically need to discover the sensors and data that fit their needs without necessarily understanding the complexities of the network itself. The burden on users is eased if the network and its data are expressed in terms of concepts familiar to the users and their job functions, rather than in terms of the network or how it was designed. Furthermore, the task of collecting and combining data from multiple sensor networks is made easier if metadata about the data and the networks is stored in a format and conceptual models that is amenable to machine reasoning and inference. While the OGC's (Open Geospatial Consortium) SWE (Sensor Web Enablement) standards provide for the description and access to data and metadata for sensors, they do not provide facilities for abstraction, categorization, and reasoning consistent with standard technologies. Once sensors and networks are described using rich semantics (that is, by using logic to describe the sensors, the domain of interest, and the measurements) then reasoning and classification can be used to analyse and categorise data, relate measurements with similar information content, and manage, query and task sensors. This will enable types of automated processing and logical assurance built on OGC standards. The W3C SSN-XG (Semantic Sensor Networks Incubator Group) is producing a generic ontology to describe sensors, their environment and the measurements they make. The ontology provides definitions for the structure of sensors and observations, leaving the details of the observed domain unspecified. This allows abstract representations of real world entities, which are not observed directly but through their observable qualities. Domain semantics, units of measurement, time and time series, and location and mobility

  18. Battery management system with distributed wireless sensors

    Science.gov (United States)

    Farmer, Joseph C.; Bandhauer, Todd M.

    2016-02-23

    A system for monitoring parameters of an energy storage system having a multiplicity of individual energy storage cells. A radio frequency identification and sensor unit is connected to each of the individual energy storage cells. The radio frequency identification and sensor unit operates to sense the parameter of each individual energy storage cell and provides radio frequency transmission of the parameters of each individual energy storage cell. A management system monitors the radio frequency transmissions from the radio frequency identification and sensor units for monitoring the parameters of the energy storage system.

  19. Spatiotemporal variability of dimethylsulphoniopropionate on a fringing coral reef: the role of reefal carbonate chemistry and environmental variability.

    Directory of Open Access Journals (Sweden)

    Heidi L Burdett

    Full Text Available Oceanic pH is projected to decrease by up to 0.5 units by 2100 (a process known as ocean acidification, OA, reducing the calcium carbonate saturation state of the oceans. The coastal ocean is expected to experience periods of even lower carbonate saturation state because of the inherent natural variability of coastal habitats. Thus, in order to accurately project the impact of OA on the coastal ocean, we must first understand its natural variability. The production of dimethylsulphoniopropionate (DMSP by marine algae and the release of DMSP's breakdown product dimethylsulphide (DMS are often related to environmental stress. This study investigated the spatiotemporal response of tropical macroalgae (Padina sp., Amphiroa sp. and Turbinaria sp. and the overlying water column to natural changes in reefal carbonate chemistry. We compared macroalgal intracellular DMSP and water column DMSP+DMS concentrations between the environmentally stable reef crest and environmentally variable reef flat of the fringing Suleman Reef, Egypt, over 45-hour sampling periods. Similar diel patterns were observed throughout: maximum intracellular DMSP and water column DMS/P concentrations were observed at night, coinciding with the time of lowest carbonate saturation state. Spatially, water column DMS/P concentrations were highest over areas dominated by seagrass and macroalgae (dissolved DMS/P and phytoplankton (particulate DMS/P rather than corals. This research suggests that macroalgae may use DMSP to maintain metabolic function during periods of low carbonate saturation state. In the reef system, seagrass and macroalgae may be more important benthic producers of dissolved DMS/P than corals. An increase in DMS/P concentrations during periods of low carbonate saturation state may become ecologically important in the future under an OA regime, impacting larval settlement and increasing atmospheric emissions of DMS.

  20. Optical seismic sensor systems and methods

    Science.gov (United States)

    Beal, A. Craig; Cummings, Malcolm E.; Zavriyev, Anton; Christensen, Caleb A.; Lee, Keun

    2015-12-08

    Disclosed is an optical seismic sensor system for measuring seismic events in a geological formation, including a surface unit for generating and processing an optical signal, and a sensor device optically connected to the surface unit for receiving the optical signal over an optical conduit. The sensor device includes at least one sensor head for sensing a seismic disturbance from at least one direction during a deployment of the sensor device within a borehole of the geological formation. The sensor head includes a frame and a reference mass attached to the frame via at least one flexure, such that movement of the reference mass relative to the frame is constrained to a single predetermined path.

  1. MEMS sensor technology

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhuangde

    2012-01-01

    Since 1992 the author has led research group in Xi'an Jiaotong University to investigate and develop microelectro mechanical systems (MEMS) sensors, including pressure sensor, acceleration sensor, gas sensor, viscosity & density sensor, polymerase chain reaction (PCR) chip and integrated sensor etc. This paper introduces the technologies and research results related to MEMS sensors we achieved in the last 20 years.

  2. A PNPN tunnel field-effect transistor with high-k gate and low-k fringe dielectrics

    Institute of Scientific and Technical Information of China (English)

    Cui Ning; Liang Renrong; Wang Jing; Zhou Wei; Xu Jun

    2012-01-01

    A PNPN tunnel field effect transistor (TFET) with a high-k gate dielectric and a low-k fringe dielectric is introduced.The effects of the gate and fringe electric fields on the TFET's performance were investigated through two-dimensional simulations.The results showed that a high gate dielectric constant is preferable for enhancing the gate control over the channel,while a low fringe dielectric constant is useful to increase the band-to-band tunneling probability.The TFET device with the proposed structure has good switching characteristics,enhanced on-state current,and high process tolerance.It is suitable for low-power applications and could become a potential substitute in next-generation complementary metal-oxide-semiconductor technology.

  3. Human Settlements in Rural-urban Fringe%城乡结合带人居环境问题研究

    Institute of Scientific and Technical Information of China (English)

    刘丽

    2015-01-01

    On basis of human settlements theory, the research explored status quo of human settlements theory in rural-urban fringe, and analyzed and concluded predicaments confronted by rural-urban fringe, laying foundation for human settle-ments theory of rural-urban fringe.%在分析人居环境理论发展基础上,探讨了城乡结合带人居环境理论研究现状,并对我国城乡结合带现阶段普遍面临的困境进行分析总结,为城乡结合带人居环境理论的后续研究奠定基础。

  4. Location choice of Chinese urban fringe residents on employment, housing, and urban services: A case study of Nanjing

    Directory of Open Access Journals (Sweden)

    Xingping Wang

    2016-03-01

    Full Text Available Urban fringe area is the most important space for city development. It includes several complicated elements, such as population, space, and management organization. On the basis of local population attributes in the city fringe area combined with people’s movement characteristics in time and space, this article reclassifies basic public service facilities and discusses the relationship between facility layout and housing, employment, and commuter transportation. Through a questionnaire survey in Qiaobei District of the urban fringe area in Nanjing and on the basis of comparative analysis, we discuss the impact factor on the choice of housing, urban services, and the tolerance of commuting time. Our findings indicate mutual promoting and restricting connections among living, employment, and services. Workers’ living situation determines their daily behavior, such as dining, shopping, and entertainment. Furthermore, different income levels have a great influence on residents’ choices with regard to places to live and develop their careers.

  5. Viewing angle switching of liquid crystal display using fringe-field switching to control off-axis phase retardation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Young Jin; Kim, Jin Ho; Her, Jung Hwa; Lee, Seung Hee [Polymer BIN Fusion Research Center, Department of Polymer Nano-Science and Technology, Chonbuk National University, Chonju, Chonbuk 561-756 (Korea, Republic of); Park, Kyoung Ho; Lee, Joun Ho; Kim, Byeong Koo [Mobile Product Development Department, LG Display Company, Ltd, Gumi, Gyungbuk 730-350 (Korea, Republic of); Kang, Wan-Seok; Lee, Gi-Dong, E-mail: gdlee@dau.ac.k, E-mail: lsh1@chonbuk.ac.k [Department of Electronics Engineering, Dong-A University, Pusan 604-714 (Korea, Republic of)

    2010-03-03

    A viewing angle switchable liquid crystal display associated with fringe-field switching mode is proposed. In the device, one pixel is composed of a main pixel and a sub-pixel, in which both pixels are formed to generate a fringe electric field. However, the field directions are different from each other so that in the main pixel, the fringe field rotates the liquid crystal for displaying the main image, whereas it controls only the tilt angle of the liquid crystal without rotating in the sub-pixel region. In this way, phase retardation to cause leakage of light at the off-normal axis can be generated in the sub-pixel, and by utilizing the light, the main displayed image in the normal direction can be blocked in the oblique viewing direction.

  6. 冻胀过程与冻结缘特性%Process of Frost Heave and Characteristics of Frozen Fringe

    Institute of Scientific and Technical Information of China (English)

    何平; 邴慧; 张钊; 杨成松

    2004-01-01

    The complex process of soil freezing which relates to moisture field, temperature and stress field usually accompanies water migration and crystallization. The mechanism of water migration in the -frozen fringe is blurry though there have rather mature theory analyzing water migration in the unfrozen zone and fully-frozen zone. It is a visualized and easy method to calculate the potential gradient of frozen fringe by frost heave amount, the duration of the steady state of frost heaving and the coefficient of permeability based on the Darcy penetration theory, not directly considering water driving force, ice segregation temperature and the thickness of frozen fringe. The method is feasible by comparing the calculated amount of frost-heaving with the test data.

  7. TERRITORIAL DISCREPANCIES IN THE RURAL-URBAN FRINGE ZONE OF BUCHAREST

    Directory of Open Access Journals (Sweden)

    Florentina ION

    2015-06-01

    Full Text Available The rural-urban fringe area of Bucharest is the most economically dynamic region of Romania, and, at the same time, is the one, which suffered the most from the recent economic decline. The article is focused on the analysis of inequalities of social-economic variables, including differences in their spatial patterns, before and after the 2008 economic crisis. We involved two methods of inequality analysis. Gini coefficient was used to determine the overall level of inequalities in the region. Comparison with the region’s mean value was used for identification of spatial patterns of these inequalities. Our results highlight four trends in the overall level of inequality dynamics, while all the studied variables follow more or less accurately the same pattern of spatial dynamics. Our findings provide new arguments in support of the idea that the new processes in the Bucharest fringe zone follow the circular pattern, which privileges the northern part of the area, while south is the last to benefit from any new development.

  8. Physical collisions of moonlets and clumps with the Saturn's F-ring core

    CERN Document Server

    Charnoz, Sebastien

    2009-01-01

    Since 2004, observations of Saturn's F ring have revealed that the ring's core is surrounded by structures with radial scales of hundreds of kilometers, called "spirals" and "jets". Gravitational scattering by nearby moons was suggested as a potential production mechanism; however, it remained doubtful because a population of Prometheus-mass moons is needed and, obviously, such a population does not exist in the F ring region. We investigate here another mechanism: dissipative physical collisions of kilometer-size moonlets (or clumps) with the F-ring core. We show that it is a viable and efficient mechanism for producing spirals and jets, provided that massive moonlets are embedded in the F-ring core and that they are impacted by loose clumps orbiting in the F ring region, which could be consistent with recent data from ISS, VIMS and UVIS. We show also that coefficients of restitution as low as ~0.1 are needed to reproduce the radial extent of spirals and jets, suggesting that collisions are very dissipative ...

  9. Physical interpretation of the fringe shift measured on Michelson interferometer in optical media

    Energy Technology Data Exchange (ETDEWEB)

    Demjanov, V.V., E-mail: demjanov@nsma.r [Ushakov Maritime State Academy, Novorossyisk (Russian Federation)

    2010-02-15

    The shift of the interference fringe in the Michelson interferometer is absent in vacuum but present in measurements performed in dielectric media with the refractive index greater than unity. This experimental observation induced me to interpret physical processes occurred in the Michelson interferometer in a conceptually new way. I rejected the generally accepted additive rule c+-v for composition of the velocity v of the inertial body and the speed c of light as inapplicable in principle to non-inertial objects which electromagnetic waves just belong to. I used instead the non-relativistic formula of Fresnel for drag of light by a moving optical medium. This formula, and taking into account the physical effect of Lorentz contraction of the arm of interferometer, enabled me to construct the theoretical model that reproduces in essential features the parabolic dependence of the shift of the interference fringe on the dielectric permittivity of the light-carrying material. The Earth's speed relative to aether found from the experimental curve was estimated as 140-480 km/s. The range of the values refers to the projection of the speed on the horizontal plane of the experimental setup measured at various time of day and night.

  10. Vegetation of natural and artificial shorelines in Upper Klamath Basin’s fringe wetlands

    Science.gov (United States)

    Ray, Andrew M.; Irvine, Kathryn M.; Hamilton, Andy S.

    2013-01-01

    The Upper Klamath Basin (UKB) in northern California and southern Oregon supports large hypereutrophic lakes surrounded by natural and artificial shorelines. Lake shorelines contain fringe wetlands that provide key ecological services to the people of this region. These wetlands also provide a context for drawing inferences about how differing wetland types and wave exposure contribute to the vegetative assemblages in lake-fringe wetlands. Here, we summarize how elevation profiles and vegetation richness vary as a function of wave exposure and wetland type. Our results show that levee wetland shorelines are 4X steeper and support fewer species than other wetland types. We also summarize the occurrence probability of the five common wetland plant species that represent the overwhelming majority of the diversity of these wetlands. In brief, the occurrence probability of the culturally significant Nuphar lutea spp. polysepala and the invasive Phalaris arundinacea in wave exposed and sheltered sites varies based on wetland type. The occurrence probability for P. arundinacea was greatest in exposed portions of deltaic shorelines, but these trends were reversed on levees where the occurrence probability was greater in sheltered sites. The widespread Schoenoplectus acutus var. acutus occurred throughout all wetland and exposure type combinations but had a higher probability of occurrence in wave exposed sites. Results from this work will add to our current understanding of how wetland shoreline profiles interact with wave exposure to influence the occurrence probability of the dominant vegetative species in UKB’s shoreline wetlands.

  11. Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types

    Science.gov (United States)

    Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C.; Braithwaite, Colin; Kennedy, David M.; Spencer, Tom; Webster, Jody M.; Woodroffe, Colin D.

    2014-01-01

    In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy. PMID:24845540

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

    Science.gov (United States)

    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.

  13. Micro/Nano-scale Strain Distribution Measurement from Sampling Moiré Fringes.

    Science.gov (United States)

    Wang, Qinghua; Ri, Shien; Tsuda, Hiroshi

    2017-05-23

    This work describes the measurement procedure and principles of a sampling moiré technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moiré method or the spatial phase-shifting sampling moiré method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moiré fringes are generated to reconstruct a multiplication moiré pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moiré method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moiré fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moiré techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

  14. The effect of Hurricane Allen on the Bellairs fringing reef, Barbados

    Science.gov (United States)

    Mah, Anmarie J.; Stearn, Colin W.

    1986-01-01

    On August 4, 1980 Hurricane Allen damaged the northern fringing reef located just offshore from the Bellairs Research Institute of McGill University on the west coast of Barbados. During the summer and one winter month of 1981 a resurvey of the reef was done and the results were compared with a similar survey made in 1974. On a reefal scale the changes in the proportion of substrates before and after Hurricane Allen were statistically significant for all substrates and species with the exception of Millepora spp. Among the corals, Porites porites has been most affected by the catastrophe: its coverage was reduced by 96%. The other corals ( Siderastrea sidera, Porites astreoides, Montastrea annularis, and Agaricia agaricites) were reduced by 75 to 25%. Onshore transport is suggested by the high abundance of Acropora cervicornis (20%) and Madracis mirabilis (30%) in the rubble on the fringing reef (the former only grows seaward of the reef). Offshore transport is suggested by the relatively poor representation of Porites porites (32%) in the rubble. Shannon-Weaver diversity indices of the corals dropped from 1.61 to 1.26. The changes in diversity are best explained by the intermediate disturbance hypothesis.

  15. Rapid three-dimensional chromoscan system of body surface based on digital fringe projection

    Science.gov (United States)

    Wei, Bin; Liang, Jin; Li, Jie; Ren, Maodong

    2015-09-01

    This paper proposes a rapid body scanning system that uses optical digital fringe projection method. Twelve cameras and four digital projectors are placed around the human body from four different directions, so that the body surface threedimensional( 3D) point cloud data can be scanned in 5~8 seconds. It can overcome many difficulties in a traditional measurement method, such as laser scanning causes damage to human eye and low splicing accuracy using structured white light scanning system. First, an accurate calibration method based on close-range photogrammetry, is proposed and verified for calibrating the twelve cameras and the four digital projectors simultaneously, where a 1m×2m plate as calibration target with feature points pasted on its two-sides is used. An experiment indicates that the proposed calibration method, with a re-projection error less than 0.05pixels, has a considerable accuracy. The whole 3D body surface color point cloud data can be measured without splice different views of point cloud, because of the high accuracy calibration results. Then, in order to measure the whole body point cloud data with high accuracy, a combination of single and stereo camera measuring method, based on digital fringe projection, has presented to calculating 3D point cloud data. At last, a novel body chromoscan system is developed and a human body 3D digital model was scanned, by which a physical body model was manufactured using 3D printing technology.

  16. 4D metrology of flapping-wing micro air vehicle based on fringe projection

    Science.gov (United States)

    Zhang, Qican; Huang, Lei; Chin, Yao-Wei; Keong, Lau-Gih; Asundi, Anand

    2013-06-01

    Inspired by dominant flight of the natural flyers and driven by civilian and military purposes, micro air vehicle (MAV) has been developed so far by passive wing control but still pales in aerodynamic performance. Better understanding of flapping wing flight mechanism is eager to improve MAV's flight performance. In this paper, a simple and effective 4D metrology technique to measure full-field deformation of flapping membrane wing is presented. Based on fringe projection and 3D Fourier analysis, the fast and complex dynamic deformation, including wing rotation and wing stroke, of a flapping wing during its flight can be accurately reconstructed from the deformed fringe patterns recorded by a highspeed camera. An experiment was carried on a flapping-wing MAV with 5-cm span membrane wing beating at 30 Hz, and the results show that this method is effective and will be useful to the aerodynamicist or micro aircraft designer for visualizing high-speed complex wing deformation and consequently aid the design of flapping wing mechanism to enhanced aerodynamic performance.

  17. Physical interpretation of the fringe shift measured on Michelson interferometer in optical media

    CERN Document Server

    Demjanov, V V

    2009-01-01

    The shift of the interference fringe in the Michelson interferometer is absent in vacuum but present in measurements performed in dielectric media. This experimental observation induced me to interpret physical processes occurred in the Michelson interferometer in a conceptually new way. I rejected the generally accepted additive rule c+V or c-V for composition of the velocity V of the inertial body and the speed c of light as inapplicable in principle to non-inertial objects which electromagnetic waves just belong to. I used instead the non-relativistic formula of Fresnel for drag of light by a moving optical medium. The latter, and taking into account the physical effect of Lorentz contraction, enabled me to construct the theoretical model that reproduces in essential features the parabolic dependence of the fringe shift on the dielectric permittivity of the light-carrying material. The Earth's speed V relative to aether found from the linear portion of the experimental curve was estimated as 140-480 km/s.

  18. Temporal phase unwrapping algorithms for fringe projection profilometry: A comparative review

    Science.gov (United States)

    Zuo, Chao; Huang, Lei; Zhang, Minliang; Chen, Qian; Asundi, Anand

    2016-10-01

    In fringe projection profilometry (FPP), temporal phase unwrapping is an essential procedure to recover an unambiguous absolute phase even in the presence of large discontinuities or spatially isolated surfaces. So far, there are typically three groups of temporal phase unwrapping algorithms proposed in the literature: multi-frequency (hierarchical) approach, multi-wavelength (heterodyne) approach, and number-theoretical approach. In this paper, the three methods are investigated and compared in detail by analytical, numerical, and experimental means. The basic principles and recent developments of the three kind of algorithms are firstly reviewed. Then, the reliability of different phase unwrapping algorithms is compared based on a rigorous stochastic noise model. Furthermore, this noise model is used to predict the optimum fringe period for each unwrapping approach, which is a key factor governing the phase measurement accuracy in FPP. Simulations and experimental results verified the correctness and validity of the proposed noise model as well as the prediction scheme. The results show that the multi-frequency temporal phase unwrapping provides the best unwrapping reliability, while the multi-wavelength approach is the most susceptible to noise-induced unwrapping errors.

  19. Reproducible strain measurement in electronic devices by applying integer multiple to scanning grating in scanning moiré fringe imaging

    Directory of Open Access Journals (Sweden)

    Suhyun Kim

    2014-10-01

    Full Text Available Scanning moiré fringe (SMF imaging by high-angle annular dark field scanning transmission electron microscopy was used to measure the strain field in the channel of a transistor with a CoSi2 source and drain. Nanometer-scale SMFs were formed with a scanning grating size of ds at integer multiples of the Si crystal lattice spacing dl (ds ∼ ndl, n = 2, 3, 4, 5. The moiré fringe formula was modified to establish a method for quantifying strain measurement. We showed that strain fields in a transistor measured by SMF images were reproducible with an accuracy of 0.02%.

  20. Twin-core fiber-based sensor for measuring the strain and bending simultaneously

    Science.gov (United States)

    Yang, Yuanyuan; Zhang, Yaxun; Liu, Zhihai; Yang, Jun; Yuan, Libo

    2013-08-01

    A novel composite interferometer sensor is presented and its sensing characteristics are investigated. Based on the infiber integrated Michelson interferometer, a quartz tube is used to encapsulate the ends of the twin-core fiber and single mode fiber to form the dual extrinsic FP cavities. Thereby, the Michelson and FP configurations are integrated into a single fiber, which we call it Michelson-FP composite interferometer sensor. The novel sensor can respond to the axial strain and radial bending simultaneously. We have derived and analyzed the interferometer principle of the new structure. The analysis results show that the interferometer sensor could be considered as the superposition of Michelson interferometer and FP interferometer. Moreover, we establish a testing system and conduct a series of experiments to investigate the strain and bending characteristics. We measure the reflection spectra with the spectrum analyzer. The spectral response of the composite interferometer sensor presents two pattern fringes with different frequencies due to the respective optical path interferometers. The experimental results indicate that the composite interferometer sensor is very sensitive to the strain and bending characteristics, and the presented sensor has different strain and bending sensitivity coefficients. Due to these characteristics, the presented sensor might be able to measure the strain and bending characteristics simultaneously. In conclusion, the presented novel interferometer sensor is of compact structure, high integration and good strain and bending sensing characteristics. Thus, many types of fiber-optic sensors may be built based on it.

  1. Localization and Tracking of Implantable Biomedical Sensors

    Directory of Open Access Journals (Sweden)

    Ilknur Umay

    2017-03-01

    Full Text Available Implantable sensor systems are effective tools for biomedical diagnosis, visualization and treatment of various health conditions, attracting the interest of researchers, as well as healthcare practitioners. These systems efficiently and conveniently provide essential data of the body part being diagnosed, such as gastrointestinal (temperature, pH, pressure parameter values, blood glucose and pressure levels and electrocardiogram data. Such data are first transmitted from the implantable sensor units to an external receiver node or network and then to a central monitoring and control (computer unit for analysis, diagnosis and/or treatment. Implantable sensor units are typically in the form of mobile microrobotic capsules or implanted stationary (body-fixed units. In particular, capsule-based systems have attracted significant research interest recently, with a variety of applications, including endoscopy, microsurgery, drug delivery and biopsy. In such implantable sensor systems, one of the most challenging problems is the accurate localization and tracking of the microrobotic sensor unit (e.g., robotic capsule inside the human body. This article presents a literature review of the existing localization and tracking techniques for robotic implantable sensor systems with their merits and limitations and possible solutions of the proposed localization methods. The article also provides a brief discussion on the connection and cooperation of such techniques with wearable biomedical sensor systems.

  2. Localization and Tracking of Implantable Biomedical Sensors.

    Science.gov (United States)

    Umay, Ilknur; Fidan, Barış; Barshan, Billur

    2017-03-13

    Implantable sensor systems are effective tools for biomedical diagnosis, visualization and treatment of various health conditions, attracting the interest of researchers, as well as healthcare practitioners. These systems efficiently and conveniently provide essential data of the body part being diagnosed, such as gastrointestinal (temperature, pH, pressure) parameter values, blood glucose and pressure levels and electrocardiogram data. Such data are first transmitted from the implantable sensor units to an external receiver node or network and then to a central monitoring and control (computer) unit for analysis, diagnosis and/or treatment. Implantable sensor units are typically in the form of mobile microrobotic capsules or implanted stationary (body-fixed) units. In particular, capsule-based systems have attracted significant research interest recently, with a variety of applications, including endoscopy, microsurgery, drug delivery and biopsy. In such implantable sensor systems, one of the most challenging problems is the accurate localization and tracking of the microrobotic sensor unit (e.g., robotic capsule) inside the human body. This article presents a literature review of the existing localization and tracking techniques for robotic implantable sensor systems with their merits and limitations and possible solutions of the proposed localization methods. The article also provides a brief discussion on the connection and cooperation of such techniques with wearable biomedical sensor systems.

  3. Localization and Tracking of Implantable Biomedical Sensors

    Science.gov (United States)

    Umay, Ilknur; Fidan, Barış; Barshan, Billur

    2017-01-01

    Implantable sensor systems are effective tools for biomedical diagnosis, visualization and treatment of various health conditions, attracting the interest of researchers, as well as healthcare practitioners. These systems efficiently and conveniently provide essential data of the body part being diagnosed, such as gastrointestinal (temperature, pH, pressure) parameter values, blood glucose and pressure levels and electrocardiogram data. Such data are first transmitted from the implantable sensor units to an external receiver node or network and then to a central monitoring and control (computer) unit for analysis, diagnosis and/or treatment. Implantable sensor units are typically in the form of mobile microrobotic capsules or implanted stationary (body-fixed) units. In particular, capsule-based systems have attracted significant research interest recently, with a variety of applications, including endoscopy, microsurgery, drug delivery and biopsy. In such implantable sensor systems, one of the most challenging problems is the accurate localization and tracking of the microrobotic sensor unit (e.g., robotic capsule) inside the human body. This article presents a literature review of the existing localization and tracking techniques for robotic implantable sensor systems with their merits and limitations and possible solutions of the proposed localization methods. The article also provides a brief discussion on the connection and cooperation of such techniques with wearable biomedical sensor systems. PMID:28335384

  4. Wearable Flexible Sensors: A Review

    KAUST Repository

    Nag, Anindya

    2017-05-18

    The paper provides a review on some of the significant research work done on wearable flexible sensors (WFS). Sensors fabricated with flexible materials have been attached to a person along with the embedded system to monitor a parameter and transfer the significant data to the monitoring unit for further analyses. The use of wearable sensors has played a quite important role to monitor physiological parameters of a person to minimize any malfunctioning happening in the body. The paper categorizes the work according to the materials used for designing the system, the network protocols and different types of activities that were being monitored. The challenges faced by the current sensing systems and future opportunities for the wearable flexible sensors regarding its market values are also briefly explained in the paper.

  5. A real-time, full-field, and low-cost velocity sensing approach for linear motion using fringe projection techniques

    Science.gov (United States)

    Su, Wei-Hung; Co, Wei-Ting

    2016-06-01

    A velocity sensing approach using the fringe projection technique is presented. The moving object is projected with a sinusoidal fringe pattern. A CCD camera located at a different view angle observes the projected fringes on the dynamic object. The long exposure time of the CCD camera makes the fringes blurred by linear motion. The blurred fringes provide additional information to describe the depth displacement, and therefore the velocity vector can be identified. There is no need to take multiple-shot measurements to address the change in 3D positions at a sequence of time. Only one-shot measurement is required. Consequently, there is no need to perform image registration. The full-field approach also makes it possible to simultaneously inspect several objects.

  6. A 3D shape retrieval method for orthogonal fringe projection based on a combination of variational image decomposition and variational mode decomposition

    Science.gov (United States)

    Li, Biyuan; Tang, Chen; Zhu, Xinjun; Chen, Xia; Su, Yonggang; Cai, Yuanxue

    2016-11-01

    The orthogonal fringe projection technique has as wide as long practical application nowadays. In this paper, we propose a 3D shape retrieval method for orthogonal composite fringe projection based on a combination of variational image decomposition (VID) and variational mode decomposition (VMD). We propose a new image decomposition model to extract the orthogonal fringe. Then we introduce the VMD method to separate the horizontal and vertical fringe from the orthogonal fringe. Lastly, the 3D shape information is obtained by the differential 3D shape retrieval method (D3D). We test the proposed method on a simulated pattern and two actual objects with edges or abrupt changes in height, and compare with the recent, related and advanced differential 3D shape retrieval method (D3D) in terms of both quantitative evaluation and visual quality. The experimental results have demonstrated the validity of the proposed method.

  7. Load sensor

    NARCIS (Netherlands)

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder for

  8. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  9. Optical Fiber Temperature and Torsion Sensor Based on Lyot-Sagnac Interferometer.

    Science.gov (United States)

    Shao, Li-Yang; Zhang, Xinpu; He, Haijun; Zhang, Zhiyong; Zou, Xihua; Luo, Bin; Pan, Wei; Yan, Lianshan

    2016-10-24

    An optical fiber temperature and torsion sensor has been proposed by employing the Lyot-Sagnac interferometer, which was composed by inserting two sections of high-birefringence (HiBi) fiber into the Sagnac loop. The two inserted sections of HiBi fiber have different functions; while one section acts as the temperature sensitive region, the other can be used as reference fiber. The temperature and twist sensor based on the proposed interferometer structure have been experimentally demonstrated. The experimental results show that the envelope of the output spectrum will shift with the temperature evolution. The temperature sensitivity is calculated to be -17.99 nm/°C, which is enlarged over 12 times compared to that of the single Sagnac interferometer. Additionally, the fringe visibility of the spectrum will change due to the fiber twist, and the test results reveal that the fringe visibility and twist angle perfectly conform to a Sine relationship over a 360° twist angle. Consequently, simultaneous torsion and temperature measurement could be realized by detecting the envelope shift and fringe visibility of the spectrum.

  10. Evaluation of a mass flow sensor at a gin

    Science.gov (United States)

    As part of a system to optimize the cotton ginning process, a custom-built mass flow sensor was evaluated at USDA-ARS Cotton Ginning Research Unit at Stoneville, Mississippi. The mass flow sensor was fabricated based on the principle of the sensor patented by Thomasson and Sui. The optical and ele...

  11. Profilometry of discontinuous solids by means of co-phased demodulation of projected fringes with RGB encoding

    Science.gov (United States)

    Padilla, J. M.; Servin, M.; Garnica, G.

    2015-05-01

    Here we describe a 2-projectors and 1-camera setup for profilometry of discontinuous solids by means of co-phased demodulation of projected fringes and red, green, and blue (RGB) multichannel operation. The dual projection configuration for this profilometer is proposed to solve efficiently specular regions and self-occluding shadows due to discontinuities, which are the main drawbacks for a 1-projector 1-camera configuration. This is because the regions where shadows and specular reflections are generated, and the fringe contrast drops to zero, are in general different for each projection direction; thus, the resulting fringe patterns will have complementary phase information. Multichannel RGB operation allows us to work simultaneously with both projectors and to record independently the complementary fringe patterns phase-modulated by the 3D profile of the object under study. In other words, color encoding/decoding reduces the acquisition time respect to one-at-a-time grayscale operation and, in principle, enables the study of dynamic phenomena. The co-phased demodulation method implemented in this work benefits from the complex (analytic) nature of the output signals estimated with most phase demodulation methods (such as the Fourier method, and temporal phaseshifting algorithms). This allowed us to straightforwardly generate a single phase-map well-defined for the entire area of interest. Finally we assessed our proposed profilometry setup by measuring a fractured spherical cap made of (uncoated) expanded polystyrene. The results were satisfactory but in the authors' opinion this must be considered a preliminary report.

  12. Fringe Benefits Available to Public School Teachers in the Southeast. Research Report. Occasional Papers in Educational Policy Analysis.

    Science.gov (United States)

    Mabry, Rodney H.; And Others

    This project measured and evaluated the fringe benefit element of the teacher compensation package available in the 12 Southeastern Regional Council member states: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virgina. Data were collected by contacting members…

  13. Anti-spoof touchless 3D fingerprint recognition system using single shot fringe projection and biospeckle analysis

    Science.gov (United States)

    Chatterjee, Amit; Bhatia, Vimal; Prakash, Shashi

    2017-08-01

    Fingerprint is a unique, un-alterable and easily collected biometric of a human being. Although it is a 3D biological characteristic, traditional methods are designed to provide only a 2D image. This touch based mapping of 3D shape to 2D image losses information and leads to nonlinear distortions. Moreover, as only topographic details are captured, conventional systems are potentially vulnerable to spoofing materials (e.g. artificial fingers, dead fingers, false prints, etc.). In this work, we demonstrate an anti-spoof touchless 3D fingerprint detection system using a combination of single shot fringe projection and biospeckle analysis. For fingerprint detection using fringe projection, light from a low power LED source illuminates a finger through a sinusoidal grating. The fringe pattern modulated because of features on the fingertip is captured using a CCD camera. Fourier transform method based frequency filtering is used for the reconstruction of 3D fingerprint from the captured fringe pattern. In the next step, for spoof detection using biospeckle analysis a visuo-numeric algorithm based on modified structural function and non-normalized histogram is proposed. High activity biospeckle patterns are generated because of interaction of collimated laser light with internal fluid flow of the real finger sample. This activity reduces abruptly in case of layered fake prints, and is almost absent in dead or fake fingers. Furthermore, the proposed setup is fast, low-cost, involves non-mechanical scanning and is highly stable.

  14. Campaigning against Europe? The role of euroskeptic fringe and mainstream parties in the 2009 European Parliament election

    NARCIS (Netherlands)

    Adam, S.; Maier, M.; de Vreese, C.H.; Schuck, A.R.T.; Stetka, V.; Jalali, C.; Seeber, G.U.H.; Negrine, R.; Raycheva, L.; Berganza, R.; Róka, J.; Dobek-Ostrowska, B.; Nord, L.; Balzer, M.; Baumli, M.

    2013-01-01

    In this article, we analyze political parties' campaign communication during the 2009 European Parliamentary election in 11 countries (Austria, Bulgaria, Czech Republic, Germany, Hungary, The Netherlands, Poland, Portugal, Spain, Sweden, and the UK). We study which types of issues Euroskeptic fringe

  15. 215 GHz VLBI observations: Detection of fringes on the 1147 KM baseline Pico Veleta-Plateau de Bure

    NARCIS (Netherlands)

    Greve, A.; Torres, M.; Wink, J. E.; Grewing, M.; Wild, W.; Alcolea, J.; Barcia, A.; Colomer, F.; de Vincente, P.; Gomez-Gonzalez, J.; Lopez-Fernandez, I.; Graham, D. A.; Krichbaum, T. P.; Schwartz, R.; Standke, K. J.; Witzel, A.; Baudry, A.

    1995-01-01

    In a VLBI test experiment between the IRAM 3Om telescope at Pico Veleta,Spain, and one 15-m telescope of the IRAM interferometer on Plateau de Bure, France, we detected fringes at 215 GHz with signal to noise ratios between 6 8 and 10.2. On this 1147km long distance, of 0.28-0.43 milli arcseconds pr

  16. Urban expansion and transportation : the impact of urban form on commuting patterns on the city fringe of Beijing

    NARCIS (Netherlands)

    Zhao, Pengjun; Lue, Bin; de Roo, Gert

    2010-01-01

    A key issue in the development of China's growing megacities in the transport-related environmental costs due to rapid urban expansion. In light of this issue, the authors examine the impact of urban form on commuting patterns on the city fringe of Beijing. Based on household-survey data, the

  17. 29 CFR 4.1b - Payment of minimum compensation based on collectively bargained wage rates and fringe benefits...

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Payment of minimum compensation based on collectively bargained wage rates and fringe benefits applicable to employment under predecessor contract. 4.1b Section 4... Contract Labor Standards Provisions and Procedures § 4.1b Payment of minimum compensation based on...

  18. Optimization of fringe-type laser anemometers for turbine engine component testing

    Science.gov (United States)

    Seasholtz, R. G.; Oberle, L. G.; Weikle, D. H.

    1984-01-01

    The fringe type laser anemometer is analyzed using the Cramer-Rao bound for the variance of the estimate of the Doppler frequency as a figure of merit. Mie scattering theory is used to calculate the Doppler signal wherein both the amplitude and phase of the scattered light are taken into account. The noise from wall scatter is calculated using the wall bidirectional reflectivity and the irradiance of the incident beams. A procedure is described to determine the optimum aperture mask for the probe volume located a given distance from a wall. The expected performance of counter type processors is also discussed in relation to the Cramer-Rao bound. Numerical examples are presented for a coaxial backscatter anemometer. Previously announced in STAR as N84-25019

  19. A trophic model of fringing coral reefs in Nanwan Bay, southern Taiwan suggests overfishing.

    Science.gov (United States)

    Liu, Pi-Jen; Shao, Kwang-Tsao; Jan, Rong-Quen; Fan, Tung-Yung; Wong, Saou-Lien; Hwang, Jiang-Shiou; Chen, Jen-Ping; Chen, Chung-Chi; Lin, Hsing-Juh

    2009-09-01

    Several coral reefs of Nanwan Bay, Taiwan have recently undergone shifts to macroalgal or sea anemone dominance. Thus, a mass-balance trophic model was constructed to analyze the structure and functioning of the food web. The fringing reef model was comprised of 18 compartments, with the highest trophic level of 3.45 for piscivorous fish. Comparative analyses with other reef models demonstrated that Nanwan Bay was similar to reefs with high fishery catches. While coral biomass was not lower, fish biomass was lower than those of reefs with high catches. Consequently, the sums of consumption and respiratory flows and total system throughput were also decreased. The Nanwan Bay model potentially suggests an overfished status in which the mean trophic level of the catch, matter cycling, and trophic transfer efficiency are extremely reduced.

  20. Characteristics of Speed Line Cutter and Fringe Analysis of Workpiece Surface

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2014-02-01

    Full Text Available Easy to operate, speed line cutter has a high machining cost performance, so is very popular among the majority of users. The precision of guide rails, screws and nuts used in most of the machines is not high, and the machine control cannot compensate for the screw pitch error, clearance during the transmission and machining error due to electrode wear. Furthermore, control signal may also be lost in control process. The development of speed line cutter focuses on the quality and machining stability of CNC speed line cutter. This article makes an analysis about the impact of machine’s inherent characteristics on machining workpiece surface, and concludes that analysis shall be made on the irregular fringe, therefore to heighten the machining precision.

  1. Magnetic fringe field interference between the quadrupole and corrector magnets in the CSNS/RCS

    Science.gov (United States)

    Yang, Mei; Kang, Wen; Deng, Changdong; Sun, Xianjing; Li, Li; Wu, Xi; Gong, Lingling; Cheng, Da; Zhu, Yingshun; Chen, Fusan

    2017-03-01

    The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) employs large aperture quadrupole and corrector magnets with small aspect ratios and relatively short iron to iron separations; so the fringe field interference becomes serious which results in integral field strength reduction and extra field harmonics. We have performed 3D magnetic field simulations to investigate the magnetic field interference in the magnet assemblies and made some adjustments on the magnet arrangement. The Fourier analysis is used to quantify the integral gradient reduction and field harmonic changes of the quadrupole magnets. Some magnetic field measurements are undertaken to verify the simulation results. The simulation details and the major results are presented in this paper.

  2. [Welfare policies on the fringe of capitalism: the recent situation in Brazil].

    Science.gov (United States)

    Pochmann, Marcio

    2007-01-01

    Located on the fringe of global capitalism, lacking an international currency and endowed with weak technology production and dissemination capacities, Brazil is developing its own very specific approach to social welfare policies. Its 1988 Constitution ushered in acknowledged progress in these policies during the past two decades, despite constraints due to the general behavior of its lackluster economy, with rising unemployment and a shrinking job pool. In parallel, the semi-stagnation of its per capita income has been paced by a steady stream of tax adjustments, hobbling more recent developments in social spending. All these efforts often achieve little more than upholding the wealth financialization cycle, mainly for the tiny portion of society holding public debt papers. An analysis of this specifically Brazilian situation leads to a better understanding of missed opportunities for cutting away many of Brazil's social shackles, as welfare policies have significant impacts on lower-income segments of the population.

  3. Calibration of fringe projection profilometry using an inaccurate 2D reference target

    Science.gov (United States)

    Liu, Xiaoli; Cai, Zewei; Yin, Yongkai; Jiang, Hao; He, Dong; He, Wenqi; Zhang, Zonghua; Peng, Xiang

    2017-02-01

    Recently, the camera calibration techniques based on planar reference target have been widely used in 3D fringe projection profilometry (FPP). Commonly a reference target with high-accuracy is necessary for achieving the accurate calibration. However it is costly to fabricate such a reference target, especially for those with very large or small sizes. This paper focuses on a study of calibration with an inaccurate planar target. Two major contributions are made to the FPP system calibration: (1) using the bundle adjustment strategy to optimally locate the coordinates of feature points on the planar reference target, allowing compensation for the fabrication errors, and (2) introducing a standard sphere to determine the correct scale factor, resulting in an accurate calibration results. The experimental results are also presented to demonstrate the proposed approach.

  4. Application of reactive transport modelling to growth and transport of microorganisms in the capillary fringe

    CERN Document Server

    Hron, Pavel; Bastian, Peter; Gallert, Claudia; Winter, Josef; Ippisch, Olaf

    2014-01-01

    A multicomponent multiphase reactive transport simulator has been developed to facilitate the investigation of a large variety of phenomena in porous media including component transport, diffusion, microbiological growth and decay, cell attachment and detachment and phase exchange. The coupled problem is solved using operator splitting. This approach allows a flexible adaptation of the solution strategy to the concrete problem. Moreover, the individual submodels were optimised to be able to describe behaviour of Escherichia coli (HB101 K12 pGLO) in the capillary fringe in the presence or absence of dissolved organic carbon and oxygen under steady-state and flow conditions. Steady-state and flow through experiments in a Hele-Shaw cell, filled with quartz sand, were conducted to study eutrophic bacterial growth and transport in both saturated and unsaturated porous media. As E. coli cells can form the green fluorescent protein (GFP), the cell densities, calculated by evaluation of measured fluorescence intensit...

  5. Perturbations to Saturn's F-ring strands at their closest approach to Prometheus

    Science.gov (United States)

    Giuliatti, Winter S.M.; Murray, C.D.; Gordon, M.

    2000-01-01

    The strange morphology of the F ring of Saturn is thought to be caused by the perturbing effects of two close satellites, Prometheus and Pandora. The F ring and the satellites also experience periodic close encounters as a result of differential precession arising from Saturn's oblateness. Using the orbits of the F-ring strands derived by Murray et al. (1997, Icarus 129, 304-316) the behaviour of the ring particles at their closest approach to Prometheus is analysed using numerical simulations. The results show that a gap and a wave are formed in the ring at each encounter with the satellite. However, the gap is expected to have a short lifetime due to keplerian shear. ?? 2000 Elsevier Science Ltd. All rights reserved.

  6. Acceleration Term at ASL FRING as a Tool to Improve Space VLBI Sensitivity

    Science.gov (United States)

    Kogan, L.; Likhachev, S.; Girin, I.; Ladygin, V.

    2009-08-01

    Astro Space Locator (ASL) a new postcorrelation software has been created recently in Astro Space Center (ASC), Russia. This software is created specifically for space VLBI project such as Radioastron and VSOP. The delay for the ground based VLBI traditionally comprised of two terms: initial delay and its rate of change in time. For space VLBI, taking into account the third term (acceleration) can be required because the satellite orbit may not be known with such a high accuracy as rotation of the Earth. The ASL software solves for all three parameters: delay, fringe rate, and acceleration. In this paper we test this algorithm and demonstrate the advantage of taking into account the acceleration term.

  7. In-plane displacement measurement in vortex metrology by synthetic network correlation fringes.

    Science.gov (United States)

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

    2013-03-01

    Recently we proposed an alternative method of displacement analysis in vortex metrology, based on the application of the Fourier optics techniques, that is suitable for an intermediate range of displacement measurements ranging below the resolution of speckle photography and above that of the conventional vortex metrology. However, for smaller displacements, we introduce an approach to perform the Fourier analysis from vortex networks. In this work, we present an enhanced method for measuring uniform in-plane displacements, taking advantage of the capability of determining the subpixel locations of vortices and having the ability to track the homologous vortices onto a plane. It is shown that high-quality fringe systems can be synthesized and analyzed to accurately measure in an extended range of displacements and for highly decorrelated speckle patterns. Experimental results supporting the validity of the method are presented and discussed.

  8. A Coordinated Approach to Food Safety and Land Use Law at the Urban Fringe.

    Science.gov (United States)

    Miller, Stephen R

    2015-01-01

    Much has been written about the rise of the local food movement in urban and suburban areas. This essay tackles an emerging outgrowth of that movement: the growing desire of urban and suburban dwellers to engage rural areas where food is produced not only to obtain food but also as a means of tourism and cultural activity. This represents a potentially much-needed means of economic development for rural areas and small farmers who are increasingly dependent on non-farm income for survival. The problem, however, is that food safety and land use laws struggle to keep up with these changes, waffling between over-regulation and de-regulation. This essay posits a legal path forward to steer clear of regulatory extremes and to help the local food movement grow and prosper at the urban fringe. We must cultivate our garden.

  9. Moiré fringe method of using warping deformation measurement of electronic components

    Science.gov (United States)

    Huang, Yanping; Huang, Biaobing; Xu, Hongji; Yan, Dongmei; Li, Wenpeng

    2010-10-01

    Computers, mobile phones, cameras and video equipment and other electronic products, Moving in the light, thin, small, high speed, high reliability, multi-functional aspects of development, Namely, 3G technology and the SOC of. Therefore, the various components of the packaging technology have become increasingly demanding, Electronic components of residual stress after encapsulation and the use of temperature changes during, Body will be made electronic packaging warpage, Seriously affect the quality of the product. Therefore, to establish a set of micron, sub-micron-level detection method for testing. In this paper, Moiré fringe method to measure warpage of electronic packages body volume, Was first proposed application of Rayleigh-Sommerfeld diffraction theory, Proof presented in this paper with a small spacing diffraction grating problems arising from the assumption can be overcome, Greatly improved the precision deformation measurement of electronic components.

  10. 3D shape measurement of shoeprint impression with structured illumination and fringe pattern analysis

    Science.gov (United States)

    Su, Xianyu; Cao, Yiping; Xiang, Liqun; Chen, Wenjing

    2002-06-01

    The shoeprint impressions of suspect left at the crime scene can sometimes tell investigators what type of shoes to be looked for. These shoeprint impressions as one of the important evidence are useful in the detection of criminals. In this paper we propose a novel technique for identifying and analyzing the 3D characteristics of shoeprint impressions. We also design 3D shoeprint impression analysis system based on the combination the 3D shape measurement with structured illumination and fringe pattern analysis. We give a detail discussion on the principle and configuration of the system. Laboratory experiments show the technique is efficient in the detection of shoeprint and in the offering the reference for judicial evidence.

  11. Real-time method for establishing a detection map for a network of sensors

    Science.gov (United States)

    Nguyen, Hung D; Koch, Mark W; Giron, Casey; Rondeau, Daniel M; Russell, John L

    2012-09-11

    A method for establishing a detection map of a dynamically configurable sensor network. This method determines an appropriate set of locations for a plurality of sensor units of a sensor network and establishes a detection map for the network of sensors while the network is being set up; the detection map includes the effects of the local terrain and individual sensor performance. Sensor performance is characterized during the placement of the sensor units, which enables dynamic adjustment or reconfiguration of the placement of individual elements of the sensor network during network set-up to accommodate variations in local terrain and individual sensor performance. The reconfiguration of the network during initial set-up to accommodate deviations from idealized individual sensor detection zones improves the effectiveness of the sensor network in detecting activities at a detection perimeter and can provide the desired sensor coverage of an area while minimizing unintentional gaps in coverage.

  12. Hydrodynamic response of a fringing coral reef to a rise in mean sea level

    Science.gov (United States)

    Taebi, Soheila; Pattiaratchi, Charitha

    2014-07-01

    Ningaloo Reef, located along the northwest coast of Australia, is one of the longest fringing coral reefs in the world extending ~300 km. Similar to other fringing reefs, it consists of a barrier reef ~1-6 km offshore with occasional gaps, backed by a shallow lagoon. Wave breaking on the reef generates radiation stress gradients that produces wave setup across the reef and lagoon and mean currents across the reef. A section of Ningaloo Reef at Sandy Bay was chosen as the focus of an intense 6-week field experiment and numerical simulation using the wave model SWAN coupled to the three-dimensional circulation model ROMS. The physics of nearshore processes such as wave breaking, wave setup and mean flow across the reef was investigated in detail by examining the various momentum balances established in the system. The magnitude of the terms and the distance of their peaks from reef edge in the momentum balance were sensitive to the changes in mean sea level, e.g. the wave forces decreased as the mean water depth increased (and hence, wave breaking dissipation was reduced). This led to an increase in the wave power at the shoreline, a slight shift of the surf zone to the lee side of the reef and changes in the intensity of the circulation. The predicted hydrodynamic fields were input into a Lagrangian particle tracking model to estimate the transport time scale of the reef-lagoon system. Flushing time of the lagoon with the open ocean was computed using two definitions in renewal of semi-enclosed water basins and revealed the sensitivity of such a transport time scale to methods. An increase in the lagoon exchange rate at smaller mean sea-level rise and the decrease at higher mean sea-level rise was predicted through flushing time computed using both methods.

  13. Mapping Sites of O-Glycosylation and Fringe Elongation on Drosophila Notch.

    Science.gov (United States)

    Harvey, Beth M; Rana, Nadia A; Moss, Hillary; Leonardi, Jessica; Jafar-Nejad, Hamed; Haltiwanger, Robert S

    2016-07-29

    Glycosylation of the Notch receptor is essential for its activity and serves as an important modulator of signaling. Three major forms of O-glycosylation are predicted to occur at consensus sites within the epidermal growth factor-like repeats in the extracellular domain of the receptor: O-fucosylation, O-glucosylation, and O-GlcNAcylation. We have performed comprehensive mass spectral analyses of these three types of O-glycosylation on Drosophila Notch produced in S2 cells and identified peptides containing all 22 predicted O-fucose sites, all 18 predicted O-glucose sites, and all 18 putative O-GlcNAc sites. Using semiquantitative mass spectral methods, we have evaluated the occupancy and relative amounts of glycans at each site. The majority of the O-fucose sites were modified to high stoichiometries. Upon expression of the β3-N-acetylglucosaminyltransferase Fringe with Notch, we observed varying degrees of elongation beyond O-fucose monosaccharide, indicating that Fringe preferentially modifies certain sites more than others. Rumi modified O-glucose sites to high stoichiometries, although elongation of the O-glucose was site-specific. Although the current putative consensus sequence for O-GlcNAcylation predicts 18 O-GlcNAc sites on Notch, we only observed apparent O-GlcNAc modification at five sites. In addition, we performed mass spectral analysis on endogenous Notch purified from Drosophila embryos and found that the glycosylation states were similar to those found on Notch from S2 cells. These data provide foundational information for future studies investigating the mechanisms of how O-glycosylation regulates Notch activity.

  14. Wave-induced extreme water levels in the Puerto Morelos fringing reef lagoon

    Directory of Open Access Journals (Sweden)

    A. Torres-Freyermuth

    2012-12-01

    Full Text Available Wave-induced extreme water levels in the Puerto Morelos fringing reef lagoon are investigated by means of a phase-resolving non-hydrostatic wave model (SWASH. This model solves the nonlinear shallow water equations including non-hydrostatic pressure. The one-dimensional version of the model is implemented in order to investigate wave transformation in fringing reefs. Firstly, the numerical model is validated with (i laboratory experiments conducted on a physical model (Demirbilek et al., 2007and (ii field observations (Coronado et al., 2007. Numerical results show good agreement with both experimental and field data. The comparison against the physical model results, for energetic wave conditions, indicates that high- and low-frequency wave transformation is well reproduced. Moreover, extreme water-level conditions measured during the passage of Hurricane Ivan in Puerto Morelos are also estimated by the numerical tool. Subsequently, the model is implemented at different along-reef locations in Puerto Morelos. Extreme water levels, wave-induced setup, and infragravity wave energy are estimated inside the reef lagoon for different storm wave conditions (Hs >2 m. The numerical results revealed a strong correlation between the offshore sea-swell wave energy and the setup. In contrast, infragravity waves are shown to be the result of a more complex pattern which heavily relies on the reef geometry. Indeed, the southern end of the reef lagoon provides evidence of resonance excitation, suggesting that the reef barrier may act as either a natural flood protection morphological feature, or as an inundation hazard enhancer depending on the incident wave conditions.

  15. Pressure sensor

    Science.gov (United States)

    Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

    2015-09-29

    Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  16. Semiconductor sensors

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Frank, E-mail: frank.hartmann@cern.c [Institut fuer Experimentelle Kernphysik, KIT, Wolfgang-Gaede-Str. 1, Karlsruhe 76131 (Germany)

    2011-02-01

    Semiconductor sensors have been around since the 1950s and today, every high energy physics experiment has one in its repertoire. In Lepton as well as Hadron colliders, silicon vertex and tracking detectors led to the most amazing physics and will continue doing so in the future. This contribution tries to depict the history of these devices exemplarily without being able to honor all important developments and installations. The current understanding of radiation damage mechanisms and recent R and D topics demonstrating the future challenges and possible technical solutions for the SLHC detectors are presented. Consequently semiconductor sensor candidates for an LHC upgrade and a future linear collider are also briefly introduced. The work presented here is a collage of the work of many individual silicon experts spread over several collaborations across the world.

  17. Corrosion sensor

    Science.gov (United States)

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  18. View and sensor planning for multi-sensor surface inspection

    Science.gov (United States)

    Gronle, Marc; Osten, Wolfgang

    2016-06-01

    Modern manufacturing processes enable the precise fabrication of high-value parts with high precision and performance. At the same time, the demand for flexible on-demand production of individual objects is continuously increasing. These requirements can only be met if inspection systems provide appropriate answers. One solution is the use of flexible, multi-sensor setups where multiple optical sensors with different fields of application are combined in one system. However, the challenge is then to assist the user in planning the inspection for individual parts. A manual planning requires an expert knowledge of the performance and functionality of every sensor. Therefore, software assistant systems help the user to objectively select the right sensors for a given inspection task. The planning step becomes still more difficult if the manufactured part has a complex form. The implication is that a sensor’s position must also be part of the planning process since it significantly influences the quality of the inspection. This paper describes a view and sensor planning approach for a multi-sensor surface inspection system in the context of optical topography measurements in the micro- and meso-scale range. In order to realize an online processing of the assistant system, a significant part of the calculations are done on the graphics processing unit (GPU).

  19. Optical fibre Fabry-Perot relative humidity sensor based on HCPCF and chitosan film

    Science.gov (United States)

    Liu, Xiaohui; Jiang, Mingshun; Sui, Qingmei; Geng, Xiangyi

    2016-09-01

    An optical fibre Fabry-Perot interferometer (FPI) sensor for relative humidity (RH) measurement is proposed. The FPI is formed by splicing a short section of hollow-core photonic crystal fibre(HCPCF) to single mode fibre and covering a chitosan film at the end of HCPCF. The refractive index of chitosan and film thickness will change with ambient RH, leading to the change in the reflected interference spectrum of FPI. RH response of the FPI sensor is analysed theoretically and demonstrated experimentally. It shows nonlinear response to RH values from 35 to 95%RH. The interference fringe shifts to shorter wavelength as RH increases with a maximum sensitivity of 0.28 nm/%RH at high RH level. And the fringe contrast also decreases as RH increases with an available maximum sensitivity of 0.5 dB/%RH. The sensor shows good stability and fast response time less than 1 min. With its advantages of compact structure, good performance, simple and safe fabrication, the proposed optical fibre FPI sensor has great potential for RH sensing.

  20. Tapered Optical Fiber Sensor for Label-Free Detection of Biomolecules

    Directory of Open Access Journals (Sweden)

    Xingwei Wang

    2011-03-01

    Full Text Available This paper presents a fast, highly sensitive and low-cost tapered optical fiber biosensor that enables the label-free detection of biomolecules. The sensor takes advantage of the interference effect between the fiber’s first two propagation modes along the taper waist region. The biomolecules bonded on the taper surface were determined by demodulating the transmission spectrum phase shift. Because of the sharp spectrum fringe signals, as well as a relatively long biomolecule testing region, the sensor displayed a fast response and was highly sensitive. To better understand the influence of various biomolecules on the sensor, a numerical simulation that varied biolayer parameters such as thickness and refractive index was performed. The results showed that the spectrum fringe shift was obvious to be measured even when the biolayer was only nanometers thick. A microchannel chip was designed and fabricated for the protection of the sensor and biotesting. Microelectromechanical systems (MEMS fabrication techniques were used to precisely control the profile and depth of the microchannel on the silicon chip with an accuracy of 2 μm. A tapered optical fiber biosensor was fabricated and evaluated with an Immune globulin G (IgG antibody-antigen pair.

  1. Microelectromechanical system pressure sensor integrated onto optical fiber by anodic bonding.

    Science.gov (United States)

    Saran, Anish; Abeysinghe, Don C; Boyd, Joseph T

    2006-03-10

    Optical microelectromechanical system pressure sensors based on the principle of Fabry-Perot interferometry have been developed and fabricated using the technique of silicon-to-silicon anodic bonding. The pressure sensor is then integrated onto an optical fiber by a novel technique of anodic bonding without use of any adhesives. In this anodic bonding technique we use ultrathin silicon of thickness 10 microm to bond the optical fiber to the sensor head. The ultrathin silicon plays the role of a stress-reducing layer, which helps the bonding of an optical fiber to silicon having conventional wafer thickness. The pressure-sensing membrane is formed by 8 microm thick ultrathin silicon acting as a membrane, thus eliminating the need for bulk silicon etching. The pressure sensor integrated onto an optical fiber is tested for static response, and experimental results indicate degradation in the fringe visibility of the Fabry-Perot interferometer. This effect was mainly due to divergent light rays from the fiber degrading the fringe visibility. This effect is demonstrated in brief by an analytical model.

  2. Optics-less Sensors for Localization of Radiation Sources

    OpenAIRE

    Caulfield, H. J.; Yaroslavsky, L. P.; Goerzen, Ch.; Umansky, S.

    2008-01-01

    A new family of radiation sensors is introduced which do not require any optics. The sensors consist of arrays of elementary sub-sensors with natural cosine-law or similar angular sensitivity supplemented with a signal processing unit that computes optimal statistical estimations of source parameters. We show, both theoretically and by computer simulation, that such sensors are capable of accurate localization and intensity estimation of a given number of radiation sources and of imaging of a...

  3. A Large Area Tactile Sensor Patch Based on Commercial Force Sensors

    Directory of Open Access Journals (Sweden)

    Alfonso García-Cerezo

    2011-05-01

    Full Text Available This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus.

  4. Thermal flow micro sensors

    OpenAIRE

    Elwenspoek, M.

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow sensors and time of flight flow sensors. Anemometers may comprise several heaters and temperature sensors and from a geometric point of view are similar sometimes for calorimetric flow sensors. We fi...

  5. Luminescence profiling of loess-dominated archaeological layers of a Chalcolithic site, Northern Negev Desert fringe, Israel

    Science.gov (United States)

    López, Gloria I.; Roskin, Joel; Bee'ri, Ron

    2017-04-01

    This study applies a pulsed-photon Portable OSL Reader (PPSL) in investigating the palaeoenviroment and stages of development of a Chalcolithic site revealed during a salvage excavation. The (Shoqet Junction) site, within late Pleistocene loess-dominated sediment, is adjacent to the meandering and ephemeral Hebron Wadi in the Beer-Sheva Valley, at the fringe of the Northern Negev Desert (Israel). The site intermittently covers approximately 8 hectares and was exposed at 0.3 - 0.5 m depths beneath a plowed field. Five areas were excavated down to 4 meters. The site was dominated by an array of underground facilities: tunnels, (capped) shafts, walls, floors and infilled cavities were found within four main layers. The site includes a mixture of sediments: large amounts of organic material, weathered bricks, a powdery loess-like unit and thin Bk horizons. The artifact assemblage is associated with the Ghassulian culture. The objectives of this multi-parameter study, which combines PPSL luminescence profiling with sedimentological and geomorphic analyses, are to (1) analyze the Chalcolithic palaeoenvironments, aeolian and fluvial processes and location and morphology of streambeds, (2) identify possible deterministic physical influences upon the occupations (3) decipher the natural stratigraphic archive and discriminate between human and natural (aeolian/fluvial) induced sedimentation (4) create relative age profiles based on portable OSL measurements and OSL ages, in order to minimize OSL dating. Three main sections were profiled: a natural section - in order to identify the natural sedimentological regime and two walls of two excavation squares down to the sites' alluvial base. A small section above a prominent Bk horizon was also profiled. Altogether 58 samples were obtained for sediment and PPSL analyses. Luminescence profiles in general fit the stratigraphic breaks and enable discrimination between layers. Plowed and surface loess give low reads. Inverse reads

  6. Microwave sensor for ice detection

    Science.gov (United States)

    Arndt, G. D.; Chu, A.; Stolarczyk, L. G.; Stolarczyk, G. L.

    1994-01-01

    A microwave technique has been developed for detecting ice build-up on the wing surfaces of commercial airliners and highway bridges. A microstrip patch antenna serves as the sensor, with changes in the resonant frequency and impedance being dependent upon the overlying layers of ice, water and glycol mixtures. The antenna sensor is conformably mounted on the wing. The depth and dielectric constants of the layers are measured by comparing the complex resonant admittance with a calibrated standard. An initial breadboard unit has been built and tested. Additional development is now underway. Another commercial application is in the robotics field of remote sensing of coal seam thickness.

  7. NEW OPTICAL SENSOR SUITE FOR ULTRAHIGH TEMPERATURE FOSSIL FUEL APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Russell G. May; Tony Peng; Tom Flynn

    2004-12-01

    Accomplishments during the Phase I of a program to develop and demonstrate technology for the instrumentation of advanced powerplants are described. Engineers from Prime Research, LC and Babcock and Wilcox Research Center collaborated to generate a list of potential applications for robust photonic sensors in existing and future boiler plants. From that list, three applications were identified as primary candidates for initial development and demonstration of high-temperature sensors in an ultrasupercritical power plant. A matrix of potential fiber optic sensor approaches was derived, and a data set of specifications for high-temperature optical fiber was produced. Several fiber optic sensor configurations, including interferometric (extrinsic and intrinsic Fabry-Perot interferometer), gratings (fiber Bragg gratings and long period gratings), and microbend sensors, were evaluated in the laboratory. In addition, progress was made in the development of materials and methods to apply high-temperature optical claddings to sapphire fibers, in order to improve their optical waveguiding properties so that they can be used in the design and fabrication of high-temperature sensors. Through refinements in the processing steps, the quality of the interface between core and cladding of the fibers was improved, which is expected to reduce scattering and attenuation in the fibers. Numerical aperture measurements of both clad and unclad sapphire fibers were obtained and used to estimate the reduction in mode volume afforded by the cladding. High-temperature sensors based on sapphire fibers were also investigated. The fabrication of an intrinsic Fabry-Perot cavity within sapphire fibers was attempted by the bulk diffusion of magnesium oxide into short localized segments of longer sapphire fibers. Fourier analysis of the fringes that resulted when the treated fiber was interrogated by a swept laser spectrometer suggested that an intrinsic cavity had been formed in the fiber. Also

  8. Surface acoustic wave (SAW) vibration sensors.

    Science.gov (United States)

    Filipiak, Jerzy; Solarz, Lech; Steczko, Grzegorz

    2011-01-01

    In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat. The theoretical study of sensor vibrations leads us to the simple isotropic model with one degree of freedom. This model allowed an explicit description of the sensor plate movement and identification of the vibrating sensor. Analysis of frequency response of the ST-cut quartz sensor plate and a damping speed of its impulse response has been conducted. The analysis above was the basis to determine the ranges of parameters for vibrating plates to be useful in electronic warning systems. Generally, operation of electronic warning systems with SAW vibration sensors is based on the analysis of signal phase changes at the working frequency of delay line after being transmitted via two circuits of concatenated four-terminal networks. Frequencies of phase changes are equal to resonance frequencies of vibrating plates of sensors. The amplitude of these phase changes is proportional to the amplitude of vibrations of a sensor plate. Both pieces of information may be sent and recorded jointly by a simple electrical unit.

  9. Surface Acoustic Wave (SAW Vibration Sensors

    Directory of Open Access Journals (Sweden)

    Jerzy Filipiak

    2011-12-01

    Full Text Available In the paper a feasibility study on the use of surface acoustic wave (SAW vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat. The theoretical study of sensor vibrations leads us to the simple isotropic model with one degree of freedom. This model allowed an explicit description of the sensor plate movement and identification of the vibrating sensor. Analysis of frequency response of the ST-cut quartz sensor plate and a damping speed of its impulse response has been conducted. The analysis above was the basis to determine the ranges of parameters for vibrating plates to be useful in electronic warning systems. Generally, operation of electronic warning systems with SAW vibration sensors is based on the analysis of signal phase changes at the working frequency of delay line after being transmitted via two circuits of concatenated four-terminal networks. Frequencies of phase changes are equal to resonance frequencies of vibrating plates of sensors. The amplitude of these phase changes is proportional to the amplitude of vibrations of a sensor plate. Both pieces of information may be sent and recorded jointly by a simple electrical unit.

  10. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  11. Cold basal conditions during surges control flow of fringing Arctic ice caps in Greenland

    Science.gov (United States)

    Cook, Samuel; Christoffersen, Poul; Todd, Joe; Palmer, Steven

    2017-04-01

    Fringing ice caps separated from larger ice sheets are rarely studied, yet they are an important part of earth's cryosphere, which has become the largest source of global sea-level rise. Understanding marginal ice caps is crucial for being able to predict sea-level change as they are responsible for up to 20% of Greenland's mass loss for 2003-2008. Studies of fringing ice caps can furthermore provide useful insights into processes operating on glaciers that surge. Surging has been the focus of much recent glaciological work, especially with reference to thermal evolution of polythermal glaciers in High Mountain Asia and the High Arctic. This has shown that the classic divide between hydrologically-controlled surges ('hard-bed') in Alaska and thermally-regulated ('soft-bed') surges elsewhere is less stark than previously assumed. Studying marginal ice caps can therefore be valuable in several ways. The largest fringing ice cap in Greenland is Flade Isblink. Previous work has established that this ice cap is showing a range of dynamic behaviour, including subglacial lake drainage and varied patterns of mass-balance change. In particular, a substantial surge, assumed to be caused by a version of the thermally-regulated mechanism, occurred between 1996 and 2000, making the ice cap a useful case study for investigating this process. Here we investigate the surge on Flade Isblink using the open-source, Full-Stokes model Elmer/Ice to invert for basal conditions and englacial temperatures using the adjoint method. We specifically study steady-state conditions representative of the active surge phase in 2000, and the subsequent quiescent phase, using patterns of surface velocity observed in 2000, 2005, 2008 and 2015. Under constant geometry, temperature and geothermal heat, it is shown that surging increases basal freezing rates by over 60% across an area that is twice as large as the area over which the bed freezes in the quiescent phase. The process responsible for this

  12. Nutrient variations and isotopic evidences of particulate organic matter provenance in fringing reefs, South China

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Di; Cao, Wenzhi, E-mail: wzcao@xmu.edu.cn; Liang, Ying; Huang, Zheng

    2016-10-01

    Nutrient over-enrichment is considered to be one of the causes of coral decline. Increase in traditional fishing in the Xuwen National Coral Reefs Reserve tract (XW) and tourism around the Sanya National Coral Reefs Reserve tract (SY) are causing this coral decline. This study reviews the current state of knowledge of the nutrient status of coastal fringing reefs in South China and evaluates the primary sources of nutrients using stable isotope method. Surveys of seawater nutrients showed that the seawater remained clean in both the XW and SY coastal coral reef areas. Based on the isotopic differences between anthropogenic sewage and naturally occurring aquatic nutrients, the isotopic values of particulate organic matter (POM) and the C/N ratios were successfully used to identify the presence of anthropogenic nutrients in aquatic environments. The δ{sup 13}C, δ{sup 15}N and C/N compositions of POM from XW and SY (− 21.18 ± 2.11‰, 10.30 ± 5.54‰, and 5.35 ± 0.69 and − 20.80 ± 1.34‰, 7.06 ± 3.95‰, and 5.77 ± 2.15, respectively) showed statistically significant variations with the season. The δ{sup 13}C and δ{sup 15}N values of POM suggest marine and terrestrial-derived nutrient sources. Organic carbon is a mixture of marine phytoplankton, marine benthic algae and terrestrial-derived plants. The δ{sup 15}N values suggest terrestrial-derived sewage and upwelling-dominated nitrogen sources. In the presence of natural upwelling and coastal currents, coastal coral reef areas are more vulnerable to the increasing anthropogenic nutrient inputs. Anthropogenic activities might lead to large increases in the nutrient concentrations and could trigger the shift from coral- to macroalgae-dominated ecosystems, which would ultimately result in the degradation of the coastal coral reef ecosystem. These results provide some understanding of the declining coral reef ecosystem and the importance of conservation areas and coastal coral reef resource management

  13. Application of wireless sensor system on security network

    Science.gov (United States)

    Oh, Sechang; Kwon, Hyeokjun; Yoon, Hargsoon; Varadan, Vijay K.

    2010-04-01

    In this research we developed wireless sensor system for security application. We have used geophone to detect seismic signals which are generated by footsteps. Geophones are resonant devices. Therefore, vibration on the land can generate seismic waveforms which could be very similar to the signature by footstep. The signals from human footstep have weak signals to noise ratio and the signal strength is subject to the distance between the sensor and human. In order to detect weak signals from footstep, we designed and fabricated 2-stage amplification circuit which consists of active and RC filters and amplifiers. The bandwidth of filter is 0.7Hz-150Hz and the gain of amplifier is set to 1000. The wireless sensor system also developed to monitor the sensing signals at the remote place. The wireless sensor system consists of 3 units; a wireless sensor unit, a wireless receiver unit, and a monitoring unit. The wireless sensor unit transmits amplified signals from geophone with Zigbee, and the wireless receiver unit which has both Zigbee and Wi-Fi module receives signals from the sensor unit and transmits signals to the monitoring system with Zigbee and Wi-Fi, respectively. By using both Zigbee and Wi-Fi, the wireless sensor system can achieve the low power consumption and wide range coverage.

  14. Microcantilever sensor

    Science.gov (United States)

    Thundat, T.G.; Wachter, E.A.

    1998-02-17

    An improved microcantilever sensor is fabricated with at least one microcantilever attached to a piezoelectric transducer. The microcantilever is partially surface treated with a compound selective substance having substantially exclusive affinity for a targeted compound in a monitored atmosphere. The microcantilever sensor is also provided with a frequency detection means and a bending detection means. The frequency detection means is capable of detecting changes in the resonance frequency of the vibrated microcantilever in the monitored atmosphere. The bending detection means is capable of detecting changes in the bending of the vibrated microcantilever in the monitored atmosphere coactively with the frequency detection means. The piezoelectric transducer is excited by an oscillator means which provides a signal driving the transducer at a resonance frequency inducing a predetermined order of resonance on the partially treated microcantilever. Upon insertion into a monitored atmosphere, molecules of the targeted chemical attach to the treated regions of the microcantilever resulting in a change in oscillating mass as well as a change in microcantilever spring constant thereby influencing the resonant frequency of the microcantilever oscillation. Furthermore, the molecular attachment of the target chemical to the treated regions induce areas of mechanical strain in the microcantilever consistent with the treated regions thereby influencing microcantilever bending. The rate at which the treated microcantilever accumulates the target chemical is a function of the target chemical concentration. Consequently, the extent of microcantilever oscillation frequency change and bending is related to the concentration of target chemical within the monitored atmosphere. 16 figs.

  15. Advocating for active living on the rural-urban fringe: a case study of planning in the Portland, Oregon, metropolitan area.

    Science.gov (United States)

    Adler, Sy; Dobson, Noelle; Fox, Karen Perl; Weigand, Lynn

    2008-06-01

    This case study is about the politics of incorporating active-living elements into a concept plan for a new community of about 68,000 people on the edge of the Portland, Oregon, metropolitan area. Development on the rural-urban fringe is ongoing in metropolitan areas around the United States. In this article, we evaluate the product of the concept-planning process from the standpoint of the extent to which environmental elements conducive to active living were included. We also analyze four issues in which challenges to the incorporation of active-living features surfaced: choices related to transportation facilities, the design and location of retail stores, the location of schools and parks, and the location of a new town center. Overall, the Damascus/Boring Concept Plan positions the area well to promote active living. Analyses of the challenges that emerged yielded lessons for advocates regarding ways to deal with conflicts between facilitating active living and local economic development and related tax-base concerns and between active-living elements and school-district planning autonomy as well as the need for advocates to have the capacity to present alternatives to the usual financial and design approaches taken by private- and public-sector investors.

  16. GPU-based implementation of an accelerated SR-NLUT based on N-point one-dimensional sub-principal fringe patterns in computer-generated holograms

    Directory of Open Access Journals (Sweden)

    Hee-Min Choi

    2015-06-01

    Full Text Available An accelerated spatial redundancy-based novel-look-up-table (A-SR-NLUT method based on a new concept of the N-point one-dimensional sub-principal fringe pattern (N-point1-D sub-PFP is implemented on a graphics processing unit (GPU for fast calculation of computer-generated holograms (CGHs of three-dimensional (3-Dobjects. Since the proposed method can generate the N-point two-dimensional (2-D PFPs for CGH calculation from the pre-stored N-point 1-D PFPs, the loading time of the N-point PFPs on the GPU can be dramatically reduced, which results in a great increase of the computational speed of the proposed method. Experimental results confirm that the average calculation time for one-object point has been reduced by 49.6% and 55.4% compared to those of the conventional 2-D SR-NLUT methods for each case of the 2-point and 3-point SR maps, respectively.

  17. The Radio Frequency Health Node Wireless Sensor System

    Science.gov (United States)

    Valencia, J. Emilio; Stanley, Priscilla C.; Mackey, Paul J.

    2009-01-01

    The Radio Frequency Health Node (RFHN) wireless sensor system differs from other wireless sensor systems in ways originally intended to enhance utility as an instrumentation system for a spacecraft. The RFHN can also be adapted to use in terrestrial applications in which there are requirements for operational flexibility and integrability into higher-level instrumentation and data acquisition systems. As shown in the figure, the heart of the system is the RFHN, which is a unit that passes commands and data between (1) one or more commercially available wireless sensor units (optionally, also including wired sensor units) and (2) command and data interfaces with a local control computer that may be part of the spacecraft or other engineering system in which the wireless sensor system is installed. In turn, the local control computer can be in radio or wire communication with a remote control computer that may be part of a higher-level system. The remote control computer, acting via the local control computer and the RFHN, cannot only monitor readout data from the sensor units but can also remotely configure (program or reprogram) the RFHN and the sensor units during operation. In a spacecraft application, the RFHN and the sensor units can also be configured more nearly directly, prior to launch, via a serial interface that includes an umbilical cable between the spacecraft and ground support equipment. In either case, the RFHN wireless sensor system has the flexibility to be configured, as required, with different numbers and types of sensors for different applications. The RFHN can be used to effect realtime transfer of data from, and commands to, the wireless sensor units. It can also store data for later retrieval by an external computer. The RFHN communicates with the wireless sensor units via a radio transceiver module. The modular design of the RFHN makes it possible to add radio transceiver modules as needed to accommodate additional sets of wireless sensor

  18. Efficient face recognition using local derivative pattern and shifted phase-encoded fringe-adjusted joint transform correlation

    Science.gov (United States)

    Biswas, Bikram K.; Alam, Mohammad S.; Chowdhury, Suparna

    2016-04-01

    An improved shifted phase-encoded fringe-adjusted joint transform correlation technique is proposed in this paper for face recognition which can accommodate the detrimental effects of noise, illumination, and other 3D distortions such as expression and rotation variations. This technique utilizes a third order local derivative pattern operator (LDP3) followed by a shifted phase-encoded fringe-adjusted joint transform correlation (SPFJTC) operation. The local derivative pattern operator ensures better facial feature extraction in a variable environment while the SPFJTC yields robust correlation output for the desired signals. The performance of the proposed method is determined by using the Yale Face Database, Yale Face Database B, and Georgia Institute of Technology Face Database. This technique has been found to yield better face recognition rate compared to alternate JTC based techniques.

  19. Tunable fringe magnetic fields induced by converse magnetoelectric coupling in a FeGa/PMN-PT multiferroic heterostructure

    Science.gov (United States)

    Fitchorov, Trifon; Chen, Yajie; Hu, Bolin; Gillette, Scott M.; Geiler, Anton; Vittoria, Carmine; Harris, Vincent G.

    2011-12-01

    The fringe magnetic field, induced by magnetoelectric coupling in a bilayer Fe-Ga/Pb(Mg1/3Nb2/3)O3_PbTiO3 (PMN-PT) multifunctional composite, was investigated. The induced external field is characterized as having a butterfly hysteresis loop when tuned by an applied electric field. A tuning coefficient of the electrically induced fringe magnetic field is derived from the piezoelectric and magnetostrictive properties of the composite. A measured maximum tuning coefficient, 4.5 Oe/(kV cm-1), is found to agree well with theoretical prediction. This work establishes a foundation in the design of transducers based on the magnetoelectric effect.

  20. The Galeta oil spill: Pt. 1; Long-term effects on the physical structure of the mangrove fringe

    Energy Technology Data Exchange (ETDEWEB)

    Garrity, S.D.; Levings, S.C. (Coastal Zone Analysis, Sopchoppy, FL (United States)); Burns, K.A. (Bermuda Biological Station, Ferry Reach (Bermuda))

    1994-04-01

    In April 1986, more than 75 000 barrels (1.5 x 10[sup 7] l) of medium-weight crude oil spilled into Bahia las Minas on the central Caribbean coast of Panama. Changes in the physical structure of the mangrove fringe after oiling were documented over time. These included defoliation, limb loss and eventual collapse of dead trees. By 5 years after the spill, the length of shore fringed by mangroves was reduced at oiled sites relative to unoiled sites. Surviving trees at oiled sites had fewer and shorter submerged prop roots and a higher proportion of dead roots than trees at unoiled sites. These changes reduced the surface area of submerged prop roots by 33% on oiled open coast, 38% in channels and 74% in streams. (author)