Development of dynamic 3-D surface profilometry using stroboscopic interferometric measurement and vertical scanning techniques

Energy Technology Data Exchange (ETDEWEB)

Fan, K-C [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chen, L-C [Graduate Institute of Automation Technology, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd, Taipei, 106, Taiwan (China); Lin, C-D [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chang, Calvin C [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Kuo, C-F [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Chou, J-T [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China)

2005-01-01

The main objective of this technical advance is to provide a single optical interferometric framework and methodology to be capable of delivering both nano-scale static and dynamic surface profilometry. Microscopic interferometry is a powerful technique for static and dynamic characterization of micro (opto) electromechanical systems (M (O) EMS). In view of this need, a microscopic prototype based on white-light stroboscopic interferometry and the white light vertical scanning principle, was developed to achieve dynamic full-field profilometry and characterization of MEMS devices. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterization of dynamic behaviours of the device. The full-field second-mode vibration at a vibratory frequency of 68.60 kHz can be fully characterized and 3-5 nm of vertical measurement resolution as well as tens of micrometers of vertical measurement range can be easily achieved.

Surface slope metrology of highly curved x-ray optics with an interferometric microscope

Science.gov (United States)

Gevorkyan, Gevork S.; Centers, Gary; Polonska, Kateryna S.; Nikitin, Sergey M.; Lacey, Ian; Yashchuk, Valeriy V.

2017-09-01

The development of deterministic polishing techniques has given rise to vendors that manufacture high quality threedimensional x-ray optics. The surface metrology on these optics remains a difficult task. For the fabrication, vendors usually use unique surface metrology tools, generally developed on site, that are not available in the optical metrology labs at x-ray facilities. At the Advanced Light Source X-Ray Optics Laboratory, we have developed a rather straightforward interferometric-microscopy-based procedure capable of sub microradian characterization of sagittal slope variation of x-ray optics for two-dimensionally focusing and collimating (such as ellipsoids, paraboloids, etc.). In the paper, we provide the mathematical foundation of the procedure and describe the related instrument calibration. We also present analytical expression describing the ideal surface shape in the sagittal direction of a spheroid specified by the conjugate parameters of the optic's beamline application. The expression is useful when analyzing data obtained with such optics. The high efficiency of the developed measurement and data analysis procedures is demonstrated in results of measurements with a number of x-ray optics with sagittal radius of curvature between 56 mm and 480 mm. We also discuss potential areas of further improvement.

Physics of interferometric gravitational wave detectors

Indian Academy of Sciences (India)

The Caltech-MIT joint LIGO project is operating three long-baseline interferometers (one of 2 km and two of 4 km) in order to unambiguously measure the infinitesimal displacements of isolated test masses which convey the signature of gravitational waves from astrophysical sources. An interferometric gravitational wave ...

Applications of interferometrically derived terrain slopes: Normalization of SAR backscatter and the interferometric correlation coefficient

Science.gov (United States)

Werner, Charles L.; Wegmueller, Urs; Small, David L.; Rosen, Paul A.

1994-01-01

Terrain slopes, which can be measured with Synthetic Aperture Radar (SAR) interferometry either from a height map or from the interferometric phase gradient, were used to calculate the local incidence angle and the correct pixel area. Both are required for correct thematic interpretation of SAR data. The interferometric correlation depends on the pixel area projected on a plane perpendicular to the look vector and requires correction for slope effects. Methods for normalization of the backscatter and interferometric correlation for ERS-1 SAR are presented.

Robust snapshot interferometric spectropolarimetry.

Science.gov (United States)

Kim, Daesuk; Seo, Yoonho; Yoon, Yonghee; Dembele, Vamara; Yoon, Jae Woong; Lee, Kyu Jin; Magnusson, Robert

2016-05-15

This Letter describes a Stokes vector measurement method based on a snapshot interferometric common-path spectropolarimeter. The proposed scheme, which employs an interferometric polarization-modulation module, can extract the spectral polarimetric parameters Ψ(k) and Δ(k) of a transmissive anisotropic object by which an accurate Stokes vector can be calculated in the spectral domain. It is inherently strongly robust to the object 3D pose variation, since it is designed distinctly so that the measured object can be placed outside of the interferometric module. Experiments are conducted to verify the feasibility of the proposed system. The proposed snapshot scheme enables us to extract the spectral Stokes vector of a transmissive anisotropic object within tens of msec with high accuracy.

Focused-laser interferometric position sensor

International Nuclear Information System (INIS)

Friedman, Stephen J.; Barwick, Brett; Batelaan, Herman

2005-01-01

We describe a simple method to measure the position shifts of an object with a range of tens of micrometers using a focused-laser (FL) interferometric position sensor. In this article we examine the effects of mechanical vibration on FL and Michelson interferometers. We tested both interferometers using vibration amplitudes ranging from 0 to 20 μm. Our FL interferometer has a resolution much better than the diffraction grating periodicities of 10 and 14 μm used in our experiments. A FL interferometer provides improved mechanical stability at the expense of spatial resolution. Our experimental results show that Michelson interferometers cannot be used when the vibration amplitude is more than an optical wavelength. The main purpose of this article is to demonstrate that a focused-laser interferometric position sensor can be used to measure the position shifts of an object on a less sensitive, micrometer scale when the vibration amplitude is too large to use a Michelson interferometer

Probing interferometric parallax with interplanetary spacecraft

Science.gov (United States)

Rodeghiero, G.; Gini, F.; Marchili, N.; Jain, P.; Ralston, J. P.; Dallacasa, D.; Naletto, G.; Possenti, A.; Barbieri, C.; Franceschini, A.; Zampieri, L.

2017-07-01

We describe an experimental scenario for testing a novel method to measure distance and proper motion of astronomical sources. The method is based on multi-epoch observations of amplitude or intensity correlations between separate receiving systems. This technique is called Interferometric Parallax, and efficiently exploits phase information that has traditionally been overlooked. The test case we discuss combines amplitude correlations of signals from deep space interplanetary spacecraft with those from distant galactic and extragalactic radio sources with the goal of estimating the interplanetary spacecraft distance. Interferometric parallax relies on the detection of wavefront curvature effects in signals collected by pairs of separate receiving systems. The method shows promising potentialities over current techniques when the target is unresolved from the background reference sources. Developments in this field might lead to the construction of an independent, geometrical cosmic distance ladder using a dedicated project and future generation instruments. We present a conceptual overview supported by numerical estimates of its performances applied to a spacecraft orbiting the Solar System. Simulations support the feasibility of measurements with a simple and time-saving observational scheme using current facilities.

Interferometric snapshot spectro-ellipsometry.

Science.gov (United States)

Dembele, Vamara; Jin, Moonseob; Choi, Inho; Chegal, Won; Kim, Daesuk

2018-01-22

We propose a snapshot spectroscopic ellipsometry and its applications for real-time thin-film thickness measurement. The proposed system employs an interferometric polarization-modulation module that can measure the spectroscopic ellipsometric phase for thin-film deposited on a substrate with a measurement speed of around 20 msec. It requires neither moving parts nor time dependent modulation devices. The accuracy of the proposed interferometric snapshot spectro-ellipsometer is analyzed through comparison with commercial equipment results.

Interferometric crosstalk reduction by phase scrambling

NARCIS (Netherlands)

Tafur Monroy, I.; Tangdiongga, E.; Jonker, R.J.W.; Waardt, de H.

2000-01-01

Interferometric crosstalk, arising from the detection of undesired signals at the same nominal wavelength, may introduce large power penalties and bit-error rate (BER) floor significantly restricting the scalability of optical networks. In this paper, interferometric crosstalk reduction in optical

MEMS Gyroscope with Interferometric Detection, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The proposed innovation is a novel MEMS gyroscope that uses micro-interferometric detection to measure the motion of the proof mass. Using an interferometric...

Interferometric interpolation of sparse marine data

KAUST Repository

Hanafy, Sherif M.

2013-10-11

We present the theory and numerical results for interferometrically interpolating 2D and 3D marine surface seismic profiles data. For the interpolation of seismic data we use the combination of a recorded Green\\'s function and a model-based Green\\'s function for a water-layer model. Synthetic (2D and 3D) and field (2D) results show that the seismic data with sparse receiver intervals can be accurately interpolated to smaller intervals using multiples in the data. An up- and downgoing separation of both recorded and model-based Green\\'s functions can help in minimizing artefacts in a virtual shot gather. If the up- and downgoing separation is not possible, noticeable artefacts will be generated in the virtual shot gather. As a partial remedy we iteratively use a non-stationary 1D multi-channel matching filter with the interpolated data. Results suggest that a sparse marine seismic survey can yield more information about reflectors if traces are interpolated by interferometry. Comparing our results to those of f-k interpolation shows that the synthetic example gives comparable results while the field example shows better interpolation quality for the interferometric method. © 2013 European Association of Geoscientists & Engineers.

Mitigation of defocusing by statics and near-surface velocity errors by interferometric least-squares migration

KAUST Repository

Sinha, Mrinal; Schuster, Gerard T.

2015-01-01

the, e.g., well logs. Reflections from this reference layer are correlated with the traces associated with reflections from deeper interfaces to get crosscorrelograms. These crosscorrelograms are then migrated using interferometric least

Standard test method for linear thermal expansion of glaze frits and ceramic whiteware materials by the interferometric method

CERN Document Server

American Society for Testing and Materials. Philadelphia

1995-01-01

1.1 This test method covers the interferometric determination of linear thermal expansion of premelted glaze frits and fired ceramic whiteware materials at temperatures lower than 1000°C (1830°F). 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Integrating interferometric SAR data with levelling measurements of land subsidence using geostatistics

NARCIS (Netherlands)

Zhou, Y.; Stein, A.; Molenaar, M.

2003-01-01

Differential Synthetic Aperture Radar (SAR) interferometric (D-InSAR) data of ground surface deformation are affected by several error sources associated with image acquisitions and data processing. In this paper, we study the use of D-InSAR for quantifying land subsidence due to groundwater

Three-step interferometric method with blind phase shifts by use of interframe correlation between interferograms

Science.gov (United States)

Muravsky, Leonid I.; Kmet', Arkady B.; Stasyshyn, Ihor V.; Voronyak, Taras I.; Bobitski, Yaroslav V.

2018-06-01

A new three-step interferometric method with blind phase shifts to retrieve phase maps (PMs) of smooth and low-roughness engineering surfaces is proposed. Evaluating of two unknown phase shifts is fulfilled by using the interframe correlation between interferograms. The method consists of two stages. The first stage provides recording of three interferograms of a test object and their processing including calculation of unknown phase shifts, and retrieval of a coarse PM. The second stage implements firstly separation of high-frequency and low-frequency PMs and secondly producing of a fine PM consisting of areal surface roughness and waviness PMs. Extraction of the areal surface roughness and waviness PMs is fulfilled by using a linear low-pass filter. The computer simulation and experiments fulfilled to retrieve a gauge block surface area and its areal surface roughness and waviness have confirmed the reliability of the proposed three-step method.

Orthogonal ribbons for suspending test masses in interferometric gravitational wave detectors

International Nuclear Information System (INIS)

Lee, B.H.; Ju, L.; Blair, D.G.

2005-01-01

We show that a simple modification of proposed ribbon suspensions for laser interferometric gravitational wave detectors can substantially reduce the amplitude of violin modes at the expense of a small deterioration of suspension thermal noise. Using low loss fused silica, large amplitude peaks which cause dynamic range problems can be reduced by 21 dB. The total number of horizontal longitudinal direction violin modes below 5 kHz is reduced to less than half that expected with conventional ribbon suspensions

Orthogonal ribbons for suspending test masses in interferometric gravitational wave detectors

Energy Technology Data Exchange (ETDEWEB)

Lee, B.H. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)]. E-mail: bhl@physics.uwa.edu.au; Ju, L. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia); Blair, D.G. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)

2005-05-23

We show that a simple modification of proposed ribbon suspensions for laser interferometric gravitational wave detectors can substantially reduce the amplitude of violin modes at the expense of a small deterioration of suspension thermal noise. Using low loss fused silica, large amplitude peaks which cause dynamic range problems can be reduced by 21 dB. The total number of horizontal longitudinal direction violin modes below 5 kHz is reduced to less than half that expected with conventional ribbon suspensions.

Super-virtual interferometric diffractions as guide stars

KAUST Repository

Dai, Wei

2011-01-01

A significant problem in seismic imaging is seismically seeing below salt structures: large velocity contrasts and the irregular geometry of the salt-sediment interface strongly defocus both the downgoing and upgoing seismic wavefields. This can result in severely defocused migration images so as to seismically render some subsalt reserves invisible. The potential cure is a good estimate of the subsalt and salt velocity distributions, but that is also the problem: severe velocity contrasts prevent the appearance of coherent subsalt reflections in the surface records so that MVA or tomographic methods can become ineffective. We now present an interferometric method for extracting the diffraction signals that emanate from diffractors, also denoted as seismic guide stars. The signal-to-noise ratio of these interferometric diffractions is enhanced by N, where N is the number of source points coincident with the receiver points. Thus, diffractions from subsalt guide stars can then be rendered visible and so can be used for velocity analysis, migration, and focusing of subsalt reflections. Both synthetic and field data records are used to demonstrate the benefits and limitations of this method. © 2011 Society of Exploration Geophysicists.

Interferometric Imaging and its Application to 4D Imaging

KAUST Repository

Sinha, Mrinal

2018-03-01

This thesis describes new interferometric imaging methods for migration and waveform inversion. The key idea is to use reflection events from a known reference reflector to ”naturally redatum” the receivers and sources to the reference reflector. Here, ”natural redatuming” is a data-driven process where the redatuming Green’s functions are obtained from the data. Interferometric imaging eliminates the statics associated with the noisy overburden above the reference reflector. To mitigate the defocussing caused by overburden errors I first propose the use of interferometric least-squares migration (ILSM) to estimate the migration image. Here, a known reflector is used as the reference interface for ILSM, and the data are naturally redatumed to this reference interface before imaging. Numerical results on synthetic and field data show that ILSM can significantly reduce the defocussing artifacts in the migration image. Next, I develop a waveform tomography approach for inverting the velocity model by mitigating the velocity errors in the overburden. Unresolved velocity errors in the overburden velocity model can cause conventional full-waveform inversion to get stuck in a local minimum. To resolve this problem, I present interferometric full-waveform inversion (IFWI), where conventional waveform tomography is reformulated so a velocity model is found that minimizes the objective function with an interferometric crosscorrelogram misfit. Numerical examples show that IFWI, compared to FWI, computes a significantly more accurate velocity model in the presence of a nearsurface with unknown velocity anomalies. I use IFWI and ILSM for 4D imaging where seismic data are recorded at different times over the same reservoir. To eliminate the time-varying effects of the near surface both data sets are virtually redatumed to a common reference interface before migration. This largely eliminates the overburden-induced statics errors in both data sets. Results with

DETECTION OF FAST TRANSIENTS WITH RADIO INTERFEROMETRIC ARRAYS

International Nuclear Information System (INIS)

Bhat, N. D. R.; Chengalur, J. N.; Gupta, Y.; Prasad, J.; Roy, J.; Kudale, S. S.; Cox, P. J.; Bailes, M.; Burke-Spolaor, S.; Van Straten, W.

2013-01-01

Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg 2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

Detection of Fast Transients with Radio Interferometric Arrays

Science.gov (United States)

Bhat, N. D. R.; Chengalur, J. N.; Cox, P. J.; Gupta, Y.; Prasad, J.; Roy, J.; Bailes, M.; Burke-Spolaor, S.; Kudale, S. S.; van Straten, W.

2013-05-01

Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

Motion of the Lambert Glacier estimated by using differential Interferometric Synthetic Aperture Radar

International Nuclear Information System (INIS)

Liu, Shuang; Tong, Xiaohua; Xie, Huan; Liu, Xiangfeng; Liu, Jun

2014-01-01

Interferometric Synthetic Aperture Radar (InSAR) is one of the most promising remote sensing technologies and has been widely applied in constructing topographic information and estimating the deformation of the Earth's surface. Ice velocity is an important parameter for calculating the mass balance and modelling ice shelve dynamics. Ice velocity is also an important indicator for climate changes. Therefore, it plays an important role in studying the global climate change and global sea level rise. In this paper, the ERS-1/2 tandem data and the ASTER GDEM are combined together to obtained the deformation in line of sight by using the differential Interferometric SAR for the Lambert Amery glacier in Antarctica. Then the surface parallel assumption is adopted in order to achieve the ice flow velocity. The results showed that ice velocity would be increased along the Lambert glacier; the maximum ice velocity would be reach about 450m/year in the study area

Time-series analysis of surface deformation at Brady Hot Springs geothermal field (Nevada) using interferometric synthetic aperture radar

Energy Technology Data Exchange (ETDEWEB)

Ali, S. T. [Univ. of Wisconsin, Madison, WI (United States); Akerley, J. [Ormat Technologies Inc., Reno, NV (United States); Baluyut, E. C. [Univ. of Wisconsin, Madison, WI (United States); Cardiff, M. [Univ. of Wisconsin, Madison, WI (United States); Davatzes, N. C. [Temple Univ., Philadelphia, PA (United States). Dept. of Earth and Environmental Science; Feigl, K. L. [Univ. of Wisconsin, Madison, WI (United States); Foxall, W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fratta, D. [Univ. of Wisconsin, Madison, WI (United States); Mellors, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spielman, P. [Ormat Technologies Inc., Reno, NV (United States); Wang, H. F. [Univ. of Wisconsin, Madison, WI (United States); Zemach, E. [Ormat Technologies Inc., Reno, NV (United States)

2016-05-01

We analyze interferometric synthetic aperture radar (InSAR) data acquired between 2004 and 2014, by the ERS-2, Envisat, ALOS and TerraSAR-X/TanDEM-X satellite missions to measure and characterize time-dependent deformation at the Brady Hot Springs geothermal field in western Nevada due to extraction of fluids. The long axis of the ~4 km by ~1.5 km elliptical subsiding area coincides with the strike of the dominant normal fault system at Brady. Within this bowl of subsidence, the interference pattern shows several smaller features with length scales of the order of ~1 km. This signature occurs consistently in all of the well-correlated interferometric pairs spanning several months. Results from inverse modeling suggest that the deformation is a result of volumetric contraction in shallow units, no deeper than 600 m, likely associated with damaged regions where fault segments mechanically interact. Such damaged zones are expected to extend downward along steeply dipping fault planes, providing a high permeability conduit to the production wells. Using time series analysis, we test the hypothesis that geothermal production drives the observed deformation. We find a good correlation between the observed deformation rate and the rate of production in the shallow wells. We also explore mechanisms that could potentially cause the observed deformation, including thermal contraction of rock, decline in pore pressure and dissolution of minerals over time.

Laser interferometric method for determining the carrier diffusion length in semiconductors

Energy Technology Data Exchange (ETDEWEB)

Manukhov, V. V. [Saint Petersburg State University (Russian Federation); Fedortsov, A. B.; Ivanov, A. S., E-mail: ivaleks58@gmail.com [Saint Petersburg Mining University (Russian Federation)

2015-09-15

A new laser interferometric method for measuring the carrier diffusion length in semiconductors is proposed. The method is based on the interference–absorption interaction of two laser radiations in a semiconductor. Injected radiation generates additional carriers in a semiconductor, which causes a change in the material’s optical constants and modulation of the probing radiation passed through the sample. When changing the distance between carrier generation and probing points, a decrease in the carrier concentration, which depends on the diffusion length, is recorded. The diffusion length is determined by comparing the experimental and theoretical dependences of the probe signal on the divergence of the injector and probe beams. The method is successfully tested on semiconductor samples with different thicknesses and surface states and can be used in scientific research and the electronics industry.

Theory, analysis and design of RF interferometric sensors

CERN Document Server

Nguyen, Cam

2012-01-01

Theory, Analysis and Design of RF Interferometric Sensors presents the theory, analysis and design of RF interferometric sensors. RF interferometric sensors are attractive for various sensing applications that require every fine resolution and accuracy as well as fast speed. The book also presents two millimeter-wave interferometric sensors realized using RF integrated circuits. The developed millimeter-wave homodyne sensor shows sub-millimeter resolution in the order of 0.05 mm without correction for the non-linear phase response of the sensor's quadrature mixer. The designed millimeter-wave double-channel homodyne sensor provides a resolution of only 0.01 mm, or 1/840th of the operating wavelength, and can inherently suppress the non-linearity of the sensor's quadrature mixer. The experimental results of displacement and velocity measurement are presented as a way to demonstrate the sensing ability of the RF interferometry and to illustrate its many possible applications in sensing. The book is succinct, ye...

An automatic evaluation method for the surface profile of a microlens array using an optical interferometric microscope

International Nuclear Information System (INIS)

Lin, Chern-Sheng; Loh, Guo-Hao; Fu, Shu-Hsien; Chang, Hsun-Kai; Yang, Shih-Wei; Yeh, Mau-Shiun

2010-01-01

In this paper, an automatic evaluation method for the surface profile of a microlens array using an optical interferometric microscope is presented. For inspecting the microlens array, an XY-table is used to position it. With a He–Ne laser beam and optical fiber as a probing light, the measured image is sent to the computer to analyze the surface profile. By binary image slicing and area recognition, this study located the center of each ring and determined the substrate of the microlens array image through the background of the entire microlens array interference image. The maximum and minimum values of every segment brightness curve were determined corresponding to the change in the segment phase angle from 0° to 180°. According to the ratio of the actual ring area and the ideal ring area, the area ratio method was adopted to find the phase-angle variation of the interference ring. Based on the ratio of actual ring brightness and the ideal ring brightness, the brightness ratio method was used to determine the phase-angle variation of the interference ring fringe. The area ratio method and brightness ratio method are interchangeable in precisely determining the phase angles of the innermost and outermost rings of the interference fringe and obtaining different microlens surface altitudes of respective pixels in the segment, to greatly increase the microlens array surface profile inspection accuracy and quality

Quantum dot-based local field imaging reveals plasmon-based interferometric logic in silver nanowire networks.

Science.gov (United States)

Wei, Hong; Li, Zhipeng; Tian, Xiaorui; Wang, Zhuoxian; Cong, Fengzi; Liu, Ning; Zhang, Shunping; Nordlander, Peter; Halas, Naomi J; Xu, Hongxing

2011-02-09

We show that the local electric field distribution of propagating plasmons along silver nanowires can be imaged by coating the nanowires with a layer of quantum dots, held off the surface of the nanowire by a nanoscale dielectric spacer layer. In simple networks of silver nanowires with two optical inputs, control of the optical polarization and phase of the input fields directs the guided waves to a specific nanowire output. The QD-luminescent images of these structures reveal that a complete family of phase-dependent, interferometric logic functions can be performed on these simple networks. These results show the potential for plasmonic waveguides to support compact interferometric logic operations.

Satellite SAR interferometric techniques applied to emergency mapping

Science.gov (United States)

Stefanova Vassileva, Magdalena; Riccardi, Paolo; Lecci, Daniele; Giulio Tonolo, Fabio; Boccardo Boccardo, Piero; Chiesa, Giuliana; Angeluccetti, Irene

2017-04-01

This paper aim to investigate the capabilities of the currently available SAR interferometric algorithms in the field of emergency mapping. Several tests have been performed exploiting the Copernicus Sentinel-1 data using the COTS software ENVI/SARscape 5.3. Emergency Mapping can be defined as "creation of maps, geo-information products and spatial analyses dedicated to providing situational awareness emergency management and immediate crisis information for response by means of extraction of reference (pre-event) and crisis (post-event) geographic information/data from satellite or aerial imagery". The conventional differential SAR interferometric technique (DInSAR) and the two currently available multi-temporal SAR interferometric approaches, i.e. Permanent Scatterer Interferometry (PSI) and Small BAseline Subset (SBAS), have been applied to provide crisis information useful for the emergency management activities. Depending on the considered Emergency Management phase, it may be distinguished between rapid mapping, i.e. fast provision of geospatial data regarding the area affected for the immediate emergency response, and monitoring mapping, i.e. detection of phenomena for risk prevention and mitigation activities. In order to evaluate the potential and limitations of the aforementioned SAR interferometric approaches for the specific rapid and monitoring mapping application, five main factors have been taken into account: crisis information extracted, input data required, processing time and expected accuracy. The results highlight that DInSAR has the capacity to delineate areas affected by large and sudden deformations and fulfills most of the immediate response requirements. The main limiting factor of interferometry is the availability of suitable SAR acquisition immediately after the event (e.g. Sentinel-1 mission characterized by 6-day revisiting time may not always satisfy the immediate emergency request). PSI and SBAS techniques are suitable to produce

Investigation of organic light emitting diodes for interferometric purposes

Science.gov (United States)

Pakula, Anna; Zimak, Marzena; Sałbut, Leszek

2011-05-01

Recently the new type of light source has been introduced to the market. Organic light emitting diode (OLED) is not only interesting because of the low applying voltage, wide light emitting areas and emission efficiency. It gives the possibility to create a light source of a various shape, various color and in the near future very likely even the one that will change shape and spectrum in time in controlled way. Those opportunities have not been in our reach until now. In the paper authors try to give an answer to the question if the new light source -OLED - is suitable for interferometric purposes. Tests cover the short and long term spectrum stability, spectrum changes due to the emission area selection. In the paper the results of two OLEDs (red and white) are shown together with the result of an attempt to use them in an interferometric setup.

Detection of surface deformation and ionospheric perturbation by the North Korea nuclear test

Science.gov (United States)

Park, S. C.; Lee, W. J.; Sohn, D. H.; Lee, D. K.; Jung, H. S.

2017-12-01

We used remote sensing data to detect the changes on surface and ionosphere due to the North Korea nuclear test. To analyze the surface deformation before and after the 6th North Korea (NK) nuclear test, we used Satellite Aperture Radar (SAR) images. It was reported that there were some surface deformation with about 10 cm by the 4th test (Wei, 2017) and the 5th test (Jo, 2017) using Interferometric SAR (InSAR) technique. However we could not obtain surface deformation by the 6th test using InSAR with Advanced Land Observation Satellite 2 (ALOS-2) data because of low coherence in the area close to the epicenter. Although the low coherence can be occurred due to several reasons, the main reason may be large deformation in this particular case. Therefore we applied pixel offset method to measure the amount of surface deformation in the area with low coherence. Pixel offset method calculates the deformation in the directions along track and Line-of-Sight (LOS) using cross correlation of intensity of two SAR images before and after the event for a pixel and is used frequently to obtain large deformation of glacier (e.g. Lee et al., 2015). Applying pixel offset method to the area of the 6th NK nuclear test, we obtained about 3 m surface deformation in maximum. It seems that the larger deformation occurs as the mountain slope is steeper.We then analyzed ionospheric perturbation using Global Navigation Satellite System (GNSS) data. If acoustic wave by a nuclear test goes up to the ionosphere and disturbs electron density, then the changes in slant total electron content (STEC) may be detected by GNSS satellites. STEC perturbation has been reported in the previous NK nuclear tests (e.g. Park et al., 2011). We analyzed the third order derivatives of STEC for 51 GNSS stations in South Korea and found that some perturbation were appeared at 4 stations about 20 40 minutes after the test.

The fresnel interferometric imager

Science.gov (United States)

Koechlin, Laurent; Serre, Denis; Deba, Paul; Pelló, Roser; Peillon, Christelle; Duchon, Paul; Gomez de Castro, Ana Ines; Karovska, Margarita; Désert, Jean-Michel; Ehrenreich, David; Hebrard, Guillaume; Lecavelier Des Etangs, Alain; Ferlet, Roger; Sing, David; Vidal-Madjar, Alfred

2009-03-01

The Fresnel Interferometric Imager has been proposed to the European Space Agency (ESA) Cosmic Vision plan as a class L mission. This mission addresses several themes of the CV Plan: Exoplanet study, Matter in extreme conditions, and The Universe taking shape. This paper is an abridged version of the original ESA proposal. We have removed most of the technical and financial issues, to concentrate on the instrumental design and astrophysical missions. The instrument proposed is an ultra-lightweight telescope, featuring a novel optical concept based on diffraction focussing. It yields high dynamic range images, while releasing constraints on positioning and manufacturing of the main optical elements. This concept should open the way to very large apertures in space. In this two spacecraft formation-flying instrument, one spacecraft holds the focussing element: the Fresnel interferometric array; the other spacecraft holds the field optics, focal instrumentation, and detectors. The Fresnel array proposed here is a 3.6 ×3.6 m square opaque foil punched with 105 to 106 void “subapertures”. Focusing is achieved with no other optical element: the shape and positioning of the subapertures (holes in the foil) is responsible for beam combining by diffraction, and 5% to 10% of the total incident light ends up into a sharp focus. The consequence of this high number of subapertures is high dynamic range images. In addition, as it uses only a combination of vacuum and opaque material, this focussing method is potentially efficient over a very broad wavelength domain. The focal length of such diffractive focussing devices is wavelength dependent. However, this can be corrected. We have tested optically the efficiency of the chromatism correction on artificial sources (500 < λ < 750 nm): the images are diffraction limited, and the dynamic range measured on an artificial double source reaches 6.2 10 - 6. We have also validated numerical simulation algorithms for larger Fresnel

Modified interferometric imaging condition for reverse-time migration

Science.gov (United States)

Guo, Xue-Bao; Liu, Hong; Shi, Ying

2018-01-01

For reverse-time migration, high-resolution imaging mainly depends on the accuracy of the velocity model and the imaging condition. In practice, however, the small-scale components of the velocity model cannot be estimated by tomographical methods; therefore, the wavefields are not accurately reconstructed from the background velocity, and the imaging process will generate artefacts. Some of the noise is due to cross-correlation of unrelated seismic events. Interferometric imaging condition suppresses imaging noise very effectively, especially the unknown random disturbance of the small-scale part. The conventional interferometric imaging condition is extended in this study to obtain a new imaging condition based on the pseudo-Wigner distribution function (WDF). Numerical examples show that the modified interferometric imaging condition improves imaging precision.

Accurate formulas for the penalty caused by interferometric crosstalk

DEFF Research Database (Denmark)

Rasmussen, Christian Jørgen; Liu, Fenghai; Jeppesen, Palle

2000-01-01

New simple formulas for the penalty caused by interferometric crosstalk in PIN receiver systems and optically preamplified receiver systems are presented. They are more accurate than existing formulas.......New simple formulas for the penalty caused by interferometric crosstalk in PIN receiver systems and optically preamplified receiver systems are presented. They are more accurate than existing formulas....

(abstract) Studies of Interferometric Penetration into Vegetation Canopies using Multifrequency Interferometry Data at JPL

Science.gov (United States)

Hensley, Scott; Rodriguez, Ernesto; Truhafft, Bob; van Zyl, Jakob; Rosen, Paul; Werner, Charles; Madsen, Sren; Chapin, Elaine

1997-01-01

Radar interferometric observations both from spaceborne and airborne platforms have been used to generate accurate topographic maps, measure milimeter level displacements from earthquakes and volcanoes, and for making land cover classification and land cover change maps. Interferometric observations have two basic measurements, interferometric phase, which depends upon the path difference between the two antennas and the correlation. One of the key questions concerning interferometric observations of vegetated regions is where in the canopy does the interferometric phase measure the height. Results for two methods of extracting tree heights and other vegetation parameters based upon the amount of volumetric decorrelation will be presented.

Performance Analysis for Airborne Interferometric SAR Affected by Flexible Baseline Oscillation

Directory of Open Access Journals (Sweden)

Liu Zhong-sheng

2014-04-01

Full Text Available The airborne interferometric SAR platform suffers from instability factors, such as air turbulence and mechanical vibrations during flight. Such factors cause the oscillation of the flexible baseline, which leads to significant degradation of the performance of the interferometric SAR system. This study is concerned with the baseline oscillation. First, the error of the slant range model under baseline oscillation conditions is formulated. Then, the SAR complex image signal and dual-channel correlation coefficient are modeled based on the first-order, second-order, and generic slant range error. Subsequently, the impact of the baseline oscillation on the imaging and interferometric performance of the SAR system is analyzed. Finally, simulations of the echo data are used to validate the theoretical analysis of the baseline oscillation in the airborne interferometric SAR.

The 2014 interferometric imaging beauty contest

Science.gov (United States)

Monnier, John D.; Berger, Jean-Philippe; Le Bouquin, Jean-Baptiste; Tuthill, Peter G.; Wittkowski, Markus; Grellmann, Rebekka; Müller, André; Renganswany, Sridhar; Hummel, Christian; Hofmann, Karl-Heinz; Schertl, Dieter; Weigelt, Gerd; Young, John; Buscher, David; Sanchez-Bermudez, Joel; Alberdi, Antxon; Schoedel, Rainer; Köhler, Rainer; Soulez, Ferréol; Thiébaut, Éric; Kluska, Jacques; Malbet, Fabien; Duvert, Gilles; Kraus, Stefan; Kloppenborg, Brian K.; Baron, Fabien; de Wit, Willem-Jan; Rivinius, Thomas; Merand, Antoine

2014-07-01

Here we present the results of the 6th biennial optical interferometry imaging beauty contest. Taking advantage of a unique opportunity, the red supergiant VY CMa and the Mira variable R Car were observed in the astronomical H-band with three 4-telescope configurations of the VLTI-AT array using the PIONIER instrument. The community was invited to participate in the subsequent image reconstruction and interpretation phases of the project. Ten groups submitted entries to the beauty contest, and we found reasonable consistency between images obtained from independent workers using quite different algorithms. We also found that significant differences existed between the submitted images, much greater than in past beauty contests that were all based on simulated data. A novel crowd-sourcing" method allowed consensus median images to be constructed, filtering likely artifacts and retaining real features." We definitively detect strong spots on the surfaces of both stars as well as distinct circumstellar shells of emission (likely water/CO) around R Car. In a close contest, Joel Sanchez (IAA-CSIC/Spain) was named the winner of the 2014 interferometric imaging beauty contest. This process has shown that new comers" can use publicly-available imaging software to interpret VLTI/PIONIER imaging data, as long as sufficient observations are taken to have complete uv coverage { a luxury that is often missing. We urge proposers to request adequate observing nights to collect sufficient data for imaging and for time allocation committees to recognise the importance of uv coverage for reliable interpretation of interferometric data. We believe that the result of the proposed broad international project will contribute to inspiring trust in the image reconstruction processes in optical interferometry.

Interferometric detection of single gold nanoparticles calibrated against TEM size distributions

DEFF Research Database (Denmark)

Zhang, Lixue; Christensen, Sune; Bendix, Pól Martin

2015-01-01

Single nanoparticle analysis: An interferometric optical approach calibrates sizes of gold nanoparticles (AuNPs) from the interference intensities by calibrating their interferometric signals against the corresponding transmission electron microscopy measurements. This method is used to investigate...

Advanced interferometric gravitational-wave detectors

CERN Document Server

Saulson, Peter R

2019-01-01

Gravitational waves are one of the most exciting and promising emerging areas of physics and astrophysics today. The detection of gravitational waves will rank among the most significant physics discoveries of the 21st century.Advanced Interferometric Gravitational-Wave Detectors brings together many of the world's top experts to deliver an authoritative and in-depth treatment on current and future detectors. Volume I is devoted to the essentials of gravitational-wave detectors, presenting the physical principles behind large-scale precision interferometry, the physics of the underlying noise sources that limit interferometer sensitivity, and an explanation of the key enabling technologies that are used in the detectors. Volume II provides an in-depth look at the Advanced LIGO and Advanced Virgo interferometers that have just finished construction, as well as examining future interferometric detector concepts. This two-volume set will provide students and researchers the comprehensive background needed to und...

Refractive Index Compensation in Over-Determined Interferometric Systems

Directory of Open Access Journals (Sweden)

Zdeněk Buchta

2012-10-01

Full Text Available We present an interferometric technique based on a differential interferometry setup for measurement under atmospheric conditions. The key limiting factor in any interferometric dimensional measurement are fluctuations of the refractive index of air representing a dominating source of uncertainty when evaluated indirectly from the physical parameters of the atmosphere. Our proposal is based on the concept of an over-determined interferometric setup where a reference length is derived from a mechanical frame made from a material with a very low thermal coefficient. The technique allows one to track the variations of the refractive index of air on-line directly in the line of the measuring beam and to compensate for the fluctuations. The optical setup consists of three interferometers sharing the same beam path where two measure differentially the displacement while the third evaluates the changes in the measuring range, acting as a tracking refractometer. The principle is demonstrated in an experimental setup.

3D surface flow kinematics derived from airborne UAVSAR interferometric synthetic aperture radar to constrain the physical mechanisms controlling landslide motion

Science.gov (United States)

Delbridge, B. G.; Burgmann, R.; Fielding, E. J.; Hensley, S.; Schulz, W. H.

2013-12-01

This project focuses on improving our understanding of the physical mechanisms controlling landslide motion by studying the landslide-wide kinematics of the Slumgullion landslide in southwestern Colorado using interferometric synthetic aperture radar (InSAR) and GPS. The NASA/JPL UAVSAR airborne repeat-pass SAR interferometry system imaged the Slumgullion landslide from 4 look directions on eight flights in 2011 and 2012. Combining the four look directions allows us to extract the full 3-D velocity field of the surface. Observing the full 3-dimensional flow field allows us to extract the full strain tensor (assuming free surface boundary conditions and incompressible flow) since we have both the spatial resolution to take spatial derivates and full deformation information. COSMO-SkyMed(CSK) high-resolution Spotlight data was also acquired during time intervals overlapping with the UAVSAR one-week pairs, with intervals as short as one day. These observations allow for the quantitative testing of the deformation magnitude and estimated formal errors in the UAVSAR derived deformation field. We also test the agreement of the deformation at 20 GPS monitoring sites concurrently acquired by the USGS. We also utilize the temporal resolution of real-time GPS acquired by the UC Berkeley Active Tectonics Group during a temporary deployment from July 22nd - August 2nd. By combining this data with the kinematic data we hope to elucidate the response of the landslide to environmental changes such as rainfall, snowmelt, and atmospheric pressure, and consequently the mechanisms controlling the dynamics of the landslide system. To constrain the longer temporal dynamics, interferograms made from pairs of CSK images acquired in 2010, 2011, 2012 and 2013 reveal the slide deformation on a longer timescale by allowing us to measure meters of motion and see the average rates over year long intervals using pixel offset tracking of the high-resolution SAR amplitude images. The results of

LSPR and Interferometric Sensor Modalities Combined Using a Double-Clad Optical Fiber.

Science.gov (United States)

Muri, Harald Ian; Bano, Andon; Hjelme, Dag Roar

2018-01-11

We report on characterization of an optical fiber-based multi-parameter sensor concept combining localized surface plasmon resonance (LSPR) signal and interferometric sensing using a double-clad optical fiber. The sensor consists of a micro-Fabry-Perot in the form of a hemispherical stimuli-responsive hydrogel with immobilized gold nanorods on the facet of a cleaved double-clad optical fiber. The swelling degree of the hydrogel is measured interferometrically using the single-mode inner core, while the LSPR signal is measured using the multi-mode inner cladding. The quality of the interferometric signal is comparable to previous work on hydrogel micro-Fabry-Perot sensors despite having gold nanorods immobilized in the hydrogel. We characterize the effect of hydrogel swelling and variation of bulk solution refractive index on the LSPR peak wavelength. The results show that pH-induced hydrogel swelling causes only weak redshifts of the longitudinal LSPR mode, while increased bulk refractive index using glycerol and sucrose causes large blueshifts. The redshifts are likely due to reduced plasmon coupling of the side-by-side configuration as the interparticle distance increases with increasing swelling. The blueshifts with increasing bulk refractive index are likely due to alteration of the surface electronic structure of the gold nanorods donated by the anionic polymer network and glycerol or sucrose solutions. The recombination of biotin-streptavidin on gold nanorods in hydrogel showed a 7.6 nm redshift of the longitudinal LSPR. The LSPR response of biotin-streptavidin recombination is due to the change in local refractive index (RI), which is possible to discriminate from the LSPR response due to changes in bulk RI. In spite of the large LSPR shifts due to bulk refractive index, we show, using biotin-functionalized gold nanorods binding to streptavidin, that LSPR signal from gold nanorods embedded in the anionic hydrogel can be used for label-free biosensing. These

LSPR and Interferometric Sensor Modalities Combined Using a Double-Clad Optical Fiber

Directory of Open Access Journals (Sweden)

Harald Ian Muri

2018-01-01

Full Text Available We report on characterization of an optical fiber-based multi-parameter sensor concept combining localized surface plasmon resonance (LSPR signal and interferometric sensing using a double-clad optical fiber. The sensor consists of a micro-Fabry-Perot in the form of a hemispherical stimuli-responsive hydrogel with immobilized gold nanorods on the facet of a cleaved double-clad optical fiber. The swelling degree of the hydrogel is measured interferometrically using the single-mode inner core, while the LSPR signal is measured using the multi-mode inner cladding. The quality of the interferometric signal is comparable to previous work on hydrogel micro-Fabry-Perot sensors despite having gold nanorods immobilized in the hydrogel. We characterize the effect of hydrogel swelling and variation of bulk solution refractive index on the LSPR peak wavelength. The results show that pH-induced hydrogel swelling causes only weak redshifts of the longitudinal LSPR mode, while increased bulk refractive index using glycerol and sucrose causes large blueshifts. The redshifts are likely due to reduced plasmon coupling of the side-by-side configuration as the interparticle distance increases with increasing swelling. The blueshifts with increasing bulk refractive index are likely due to alteration of the surface electronic structure of the gold nanorods donated by the anionic polymer network and glycerol or sucrose solutions. The recombination of biotin-streptavidin on gold nanorods in hydrogel showed a 7.6 nm redshift of the longitudinal LSPR. The LSPR response of biotin-streptavidin recombination is due to the change in local refractive index (RI, which is possible to discriminate from the LSPR response due to changes in bulk RI. In spite of the large LSPR shifts due to bulk refractive index, we show, using biotin-functionalized gold nanorods binding to streptavidin, that LSPR signal from gold nanorods embedded in the anionic hydrogel can be used for label

Interferometric data modelling: issues in realistic data generation

International Nuclear Information System (INIS)

Mukherjee, Soma

2004-01-01

This study describes algorithms developed for modelling interferometric noise in a realistic manner, i.e. incorporating non-stationarity that can be seen in the data from the present generation of interferometers. The noise model is based on individual component models (ICM) with the application of auto regressive moving average (ARMA) models. The data obtained from the model are vindicated by standard statistical tests, e.g. the KS test and Akaike minimum criterion. The results indicate a very good fit. The advantage of using ARMA for ICMs is that the model parameters can be controlled and hence injection and efficiency studies can be conducted in a more controlled environment. This realistic non-stationary noise generator is intended to be integrated within the data monitoring tool framework

Event reconstruction using the radio-interferometric technique in the frame of AERA

Energy Technology Data Exchange (ETDEWEB)

Rogozin, Dmytro [Institut fuer Experimentelle Kernphysik, Karlsruher Institut fuer Technologie (KIT) (Germany); Collaboration: Pierre-Auger-Collaboration

2016-07-01

It is a well-known fact that there is coherent radio emission induced by extensive air-showers. This fact is exploited in the Auger Engineering Radio Array (AERA), the radio extension of the Pierre Auger Observatory. This is a unique radio experiment due to its world-largest size of 17 km{sup 2}, and due to its precise nanosecond timing calibration. These features become crucial for detection of highly inclined air-showers with their very large foot-prints, and for the ability to apply interferometric reconstruction techniques. The standard reconstruction techniques typically treat all radio stations as separate detectors. Nevertheless there is a possibility to do an interferometric analysis. This means combining all detected signals from all antennas in a specific way. In this talk we present a beam-forming interferometric technique and its application to AERA. According to the definition of the beam-forming quantities one can expect its correlation with the shower parameters such as energy of the primary particle and distance to the shower maximum. At the first step, Monte-Carlo simulations of AERA events including the noise from measured events were used to test these dependencies. The results and the future perspectives of this method are discussed with a particular emphasis on very inclined air-showers where the aforementioned correlations are assumed to be strongest.

An ultra-high frequency boundary layer Doppler/interferometric profiler

International Nuclear Information System (INIS)

Van Baelen, J.S.

1994-01-01

The planetary boundary layer (PBL) is that portion of the earth's atmosphere that is directly influenced by the earth's surface. The PBL can be vigorously turbulent and range in depth from a few hundred meters to a few kilometers. Solar energy is primarily absorbed at the earth's surface and transmitted to the free atmosphere through boundary-layer processes. An accurate portrayal of these transfers within the PBL is crucial to understand and predict many atmospheric processes from pollutant dispersion to numerical weather prediction and numerical simulations of climate change. This paper describes and discusses wind profiling techniques, focusing on the newly developed radio acoustic sounding system (RASS), and reviews past efforts to measure flux within the PBL. A new UHF wind profiling radar, the UHF Doppler/Interferometric Boundary Layer Radar, for accurately measuring both mean and flux quantities, as well as wind divergence and acoustic wave propagation, is outlined

Stabilizing operation point technique based on the tunable distributed feedback laser for interferometric sensors

Science.gov (United States)

Mao, Xuefeng; Zhou, Xinlei; Yu, Qingxu

2016-02-01

We describe a stabilizing operation point technique based on the tunable Distributed Feedback (DFB) laser for quadrature demodulation of interferometric sensors. By introducing automatic lock quadrature point and wavelength periodically tuning compensation into an interferometric system, the operation point of interferometric system is stabilized when the system suffers various environmental perturbations. To demonstrate the feasibility of this stabilizing operation point technique, experiments have been performed using a tunable-DFB-laser as light source to interrogate an extrinsic Fabry-Perot interferometric vibration sensor and a diaphragm-based acoustic sensor. Experimental results show that good tracing of Q-point was effectively realized.

Optimization of silicon oxynitrides by plasma-enhanced chemical vapor deposition for an interferometric biosensor

Science.gov (United States)

Choo, Sung Joong; Lee, Byung-Chul; Lee, Sang-Myung; Park, Jung Ho; Shin, Hyun-Joon

2009-09-01

In this paper, silicon oxynitride layers deposited with different plasma-enhanced chemical vapor deposition (PECVD) conditions were fabricated and optimized, in order to make an interferometric sensor for detecting biochemical reactions. For the optimization of PECVD silicon oxynitride layers, the influence of the N2O/SiH4 gas flow ratio was investigated. RF power in the PEVCD process was also adjusted under the optimized N2O/SiH4 gas flow ratio. The optimized silicon oxynitride layer was deposited with 15 W in chamber under 25/150 sccm of N2O/SiH4 gas flow rates. The clad layer was deposited with 20 W in chamber under 400/150 sccm of N2O/SiH4 gas flow condition. An integrated Mach-Zehnder interferometric biosensor based on optical waveguide technology was fabricated under the optimized PECVD conditions. The adsorption reaction between bovine serum albumin (BSA) and the silicon oxynitride surface was performed and verified with this device.

Broadband infrared beam splitter for spaceborne interferometric infrared sounder.

Science.gov (United States)

Yu, Tianyan; Liu, Dingquan; Qin, Yang

2014-10-01

A broadband infrared beam splitter (BS) on ZnSe substrate used for the spaceborne interferometric infrared sounder (SIIRS) is studied in the spectral range of 4.44-15 μm. Both broadband antireflection coating and broadband beam-splitter coating in this BS are designed and tested. To optimize the optical properties and the stability of the BS, suitable infrared materials were selected, and improved deposition techniques were applied. The designed structures matched experimental data well, and the properties of the BS met the application specification of SIIRS.

Interferometric study of the small magellanic cloud

International Nuclear Information System (INIS)

Torres, G.; Carranza, G.J.

1986-01-01

Hα interferometric observations of the general radial velocity field in the small magellanic cloud are being carried out. We present preliminary results in reasonable agreement with H I measurements. (author)

Pulse Retrieval Algorithm for Interferometric Frequency-Resolved Optical Gating Based on Differential Evolution

OpenAIRE

Hyyti, Janne; Escoto, Esmerando; Steinmeyer, Günter

2017-01-01

A novel algorithm for the ultrashort laser pulse characterization method of interferometric frequency-resolved optical gating (iFROG) is presented. Based on a genetic method, namely differential evolution, the algorithm can exploit all available information of an iFROG measurement to retrieve the complex electric field of a pulse. The retrieval is subjected to a series of numerical tests to prove robustness of the algorithm against experimental artifacts and noise. These tests show that the i...

Label-free and live cell imaging by interferometric scattering microscopy.

Science.gov (United States)

Park, Jin-Sung; Lee, Il-Buem; Moon, Hyeon-Min; Joo, Jong-Hyeon; Kim, Kyoung-Hoon; Hong, Seok-Cheol; Cho, Minhaeng

2018-03-14

Despite recent remarkable advances in microscopic techniques, it still remains very challenging to directly observe the complex structure of cytoplasmic organelles in live cells without a fluorescent label. Here we report label-free and live-cell imaging of mammalian cell, Escherischia coli , and yeast, using interferometric scattering microscopy, which reveals the underlying structures of a variety of cytoplasmic organelles as well as the underside structure of the cells. The contact areas of the cells attached onto a glass substrate, e.g. , focal adhesions and filopodia, are clearly discernible. We also found a variety of fringe-like features in the cytoplasmic area, which may reflect the folded structures of cytoplasmic organelles. We thus anticipate that the label-free interferometric scattering microscopy can be used as a powerful tool to shed interferometric light on in vivo structures and dynamics of various intracellular phenomena.

Interferometric crosstalk suppression using polarization multiplexing technique and an SOA

DEFF Research Database (Denmark)

Liu, Fenghai; Xueyan, Zheng; Pedersen, Rune Johan Skullerud

2000-01-01

Interferometric crosstalk can be greatly suppressed at 10Gb/s and 20Gb/s by using a gain saturated SOA and a polarization multiplexing technique that eliminates impairments like waveform and extinction ratio degradation from the SOA.......Interferometric crosstalk can be greatly suppressed at 10Gb/s and 20Gb/s by using a gain saturated SOA and a polarization multiplexing technique that eliminates impairments like waveform and extinction ratio degradation from the SOA....

Effects of Target Positioning Error on Motion Compensation for Airborne Interferometric SAR

Directory of Open Access Journals (Sweden)

Li Yin-wei

2013-12-01

Full Text Available The measurement inaccuracies of Inertial Measurement Unit/Global Positioning System (IMU/GPS as well as the positioning error of the target may contribute to the residual uncompensated motion errors in the MOtion COmpensation (MOCO approach based on the measurement of IMU/GPS. Aiming at the effects of target positioning error on MOCO for airborne interferometric SAR, the paper firstly deduces a mathematical model of residual motion error bring out by target positioning error under the condition of squint. And the paper analyzes the effects on the residual motion error caused by system sampling delay error, the Doppler center frequency error and reference DEM error which result in target positioning error based on the model. Then, the paper discusses the effects of the reference DEM error on the interferometric SAR image quality, the interferometric phase and the coherent coefficient. The research provides theoretical bases for the MOCO precision in signal processing of airborne high precision SAR and airborne repeat-pass interferometric SAR.

Secure space-to-space interferometric communications and its nexus to the physics of quantum entanglement

Science.gov (United States)

Duarte, F. J.

2016-12-01

The history of the probability amplitude equation | ψ > = ( | x , y > - | y , x > ) applicable to quanta pairs, propagating in different directions with entangled polarizations, is reviewed and traced back to the 1947-1949 period. The interferometric Dirac foundations common to | ψ > = ( | x , y > - | y , x > ) and the generalized N-slit interferometric equation, for indistinguishable quanta, are also described. The results from a series of experiments on N-slit laser interferometers, with intra interferometric propagation paths up to 527 m, are reviewed. Particular attention is given to explain the generation of interferometric characters, for secure space-to-space communications, which immediately collapse on attempts of interception. The design of a low divergence N-slit laser interferometer for low Earth orbit-low Earth orbit (LEO-LEO), and LEO-geostationary Earth orbit (LEO-GEO), secure interferometric communications is described and a weight assessment is provided.

Calibration of Modulation Transfer Function of Surface Profilometers with 1D and 2D Binary Pseudo-random Array Standards

International Nuclear Information System (INIS)

Yashchuk, Valeriy V.; McKinney, Wayne R.; Takacs, Peter Z.

2008-01-01

We suggest and describe the use of a binary pseudo-random grating as a standard test surface for calibration of the modulation transfer function of microscopes. Results from calibration of a MicromapTM-570 interferometric microscope are presented.

INTERFEROMETRIC SYNTHETIC APERTURE RADAR (INSAR TECHNOLOGY AND GEOMORPHOLOGY INTERPRETATION

Directory of Open Access Journals (Sweden)

M. Maghsoudi

2013-09-01

Full Text Available Geomorphology is briefly the study of landforms and their formative processes on the surface of the planet earth as human habitat. The landforms evolution and the formative processes can best be studied by technologies with main application in study of elevation. Interferometric Synthetic Aperture Radar (InSAR is the appropriate technology for this application. With phase differences calculations in radar waves, the results of this technology can extensively be interpreted for geomorphologic researches. The purpose of the study is to review the geomorphologic studies using InSAR and also the technical studies about InSAR with geomorphologic interpretations. This study states that the InSAR technology can be recommended to be employed as a fundamental for geomorphology researches.

Radon-domain interferometric interpolation for reconstruction of the near-offset gap in marine seismic data

Science.gov (United States)

Xu, Zhuo; Sopher, Daniel; Juhlin, Christopher; Han, Liguo; Gong, Xiangbo

2018-04-01

In towed marine seismic data acquisition, a gap between the source and the nearest recording channel is typical. Therefore, extrapolation of the missing near-offset traces is often required to avoid unwanted effects in subsequent data processing steps. However, most existing interpolation methods perform poorly when extrapolating traces. Interferometric interpolation methods are one particular method that have been developed for filling in trace gaps in shot gathers. Interferometry-type interpolation methods differ from conventional interpolation methods as they utilize information from several adjacent shot records to fill in the missing traces. In this study, we aim to improve upon the results generated by conventional time-space domain interferometric interpolation by performing interferometric interpolation in the Radon domain, in order to overcome the effects of irregular data sampling and limited source-receiver aperture. We apply both time-space and Radon-domain interferometric interpolation methods to the Sigsbee2B synthetic dataset and a real towed marine dataset from the Baltic Sea with the primary aim to improve the image of the seabed through extrapolation into the near-offset gap. Radon-domain interferometric interpolation performs better at interpolating the missing near-offset traces than conventional interferometric interpolation when applied to data with irregular geometry and limited source-receiver aperture. We also compare the interferometric interpolated results with those obtained using solely Radon transform (RT) based interpolation and show that interferometry-type interpolation performs better than solely RT-based interpolation when extrapolating the missing near-offset traces. After data processing, we show that the image of the seabed is improved by performing interferometry-type interpolation, especially when Radon-domain interferometric interpolation is applied.

Binary Pseudo-Random Gratings and Arrays for Calibration of Modulation Transfer Functions of Surface Profilometers

Energy Technology Data Exchange (ETDEWEB)

Barber, Samuel K.; Anderson, Erik D.; Cambie, Rossana; McKinney, Wayne R.; Takacs, Peter Z.; Stover, John C.; Voronov, Dmitriy L.; Yashchuk, Valeriy V.

2009-09-11

A technique for precise measurement of the modulation transfer function (MTF), suitable for characterization of a broad class of surface profilometers, is investigated in detail. The technique suggested in [Proc. SPIE 7077-7, (2007), Opt. Eng. 47(7), 073602-1-5 (2008)]is based on use of binary pseudo-random (BPR) gratings and arrays as standard MTF test surfaces. Unlike most conventional test surfaces, BPR gratings and arrays possess white-noise-like inherent power spectral densities (PSD), allowing the direct determination of the one- and two-dimensional MTF, respectively, with a sensitivity uniform over the entire spatial frequency range of a profiler. In the cited work, a one dimensional realization of the suggested method based on use of BPR gratings has been demonstrated. Here, a high-confidence of the MTF calibration technique is demonstrated via cross comparison measurements of a number of two dimensional BPR arrays using two different interferometric microscopes and a scatterometer. We also present the results of application of the experimentally determined MTF correction to the measurement taken with the MicromapTM-570 interferometric microscope of the surface roughness of a super-polished test mirror. In this particular case, without accounting for the instrumental MTF, the surface rms roughness over half of the instrumental spatial frequency bandwidth would be underestimated by a factor of approximately 1.4.

Frequency-resolved interferometric measurement of local density fluctuations for turbulent combustion analysis

International Nuclear Information System (INIS)

Köberl, S; Giuliani, F; Woisetschläger, J; Fontaneto, F

2010-01-01

A validation of a novel interferometric measurement technique for the frequency-resolved detection of local density fluctuation in turbulent combustion analysis was performed in this work. Two laser vibrometer systems together with a signal analyser were used to obtain frequency spectra of density fluctuations across a methane-jet flame. Since laser vibrometry is based on interferometric techniques, the derived signals are path-integrals along the measurement beam. To obtain local frequency spectra of density fluctuations, long-time-averaged measurements from each of the two systems were performed using correlation functions and cross spectra. Results were compared to data recorded by standard interferometric techniques for validation purposes. Additionally, Raman scattering and laser Doppler velocimetry were used for flame characterization

Metabolic Activity Interferometer: A Powerful Tool for Testing Antibiotics

Directory of Open Access Journals (Sweden)

Rachel R. P. Machado

2012-01-01

Full Text Available It is demonstrated that the efficiency of antibiotics can be tested using an interferometric method. Two antibiotics were used as models to show that an interferometric method to monitor the metabolic activity of slowly growing bacteria can be a safer method to judge antimicrobial properties of substances than conventional methods. The susceptibility of Mycobacterium bovis to hexane extract of Pterodon emarginatus and to the well-known antibiotic rifampicin was tested with the interferometric method and with the conventional microplate method. The microplate method revealed a potential activity of hexane extract against M. bovis. However, the interferometric method showed that the action of this substance is rather limited. Also in the case of rifampicin, the interferometric method was able to detect resistant bacteria.

Thin walled Nb tubes for suspending test masses in interferometric gravitational wave detectors

Energy Technology Data Exchange (ETDEWEB)

Lee, B.H. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)]. E-mail: bhl@physics.uwa.edu.au; Ju, L. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia); Blair, D.G. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)

2006-02-13

In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB.

Thin walled Nb tubes for suspending test masses in interferometric gravitational wave detectors

International Nuclear Information System (INIS)

Lee, B.H.; Ju, L.; Blair, D.G.

2006-01-01

In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB

The EDGE-CALIFA Survey: Interferometric Observations of 126 Galaxies with CARMA

Science.gov (United States)

Bolatto, Alberto D.; Wong, Tony; Utomo, Dyas; Blitz, Leo; Vogel, Stuart N.; Sánchez, Sebastián F.; Barrera-Ballesteros, Jorge; Cao, Yixian; Colombo, Dario; Dannerbauer, Helmut; García-Benito, Rubén; Herrera-Camus, Rodrigo; Husemann, Bernd; Kalinova, Veselina; Leroy, Adam K.; Leung, Gigi; Levy, Rebecca C.; Mast, Damián; Ostriker, Eve; Rosolowsky, Erik; Sandstrom, Karin M.; Teuben, Peter; van de Ven, Glenn; Walter, Fabian

2017-09-01

We present interferometric CO observations, made with the Combined Array for Millimeter-wave Astronomy (CARMA) interferometer, of galaxies from the Extragalactic Database for Galaxy Evolution survey (EDGE). These galaxies are selected from the Calar Alto Legacy Integral Field Area (CALIFA) sample, mapped with optical integral field spectroscopy. EDGE provides good-quality CO data (3σ sensitivity {{{Σ }}}{mol}˜ 11 {M}⊙ {{pc}}-2 before inclination correction, resolution ˜1.4 kpc) for 126 galaxies, constituting the largest interferometric CO survey of galaxies in the nearby universe. We describe the survey and data characteristics and products, then present initial science results. We find that the exponential scale lengths of the molecular, stellar, and star-forming disks are approximately equal, and galaxies that are more compact in molecular gas than in stars tend to show signs of interaction. We characterize the molecular-to-stellar ratio as a function of Hubble type and stellar mass and present preliminary results on the resolved relations between the molecular gas, stars, and star-formation rate. We then discuss the dependence of the resolved molecular depletion time on stellar surface density, nebular extinction, and gas metallicity. EDGE provides a key data set to address outstanding topics regarding gas and its role in star formation and galaxy evolution, which will be publicly available on completion of the quality assessment.

Magnonic interferometric switch for multi-valued logic circuits

Science.gov (United States)

Balynsky, Michael; Kozhevnikov, Alexander; Khivintsev, Yuri; Bhowmick, Tonmoy; Gutierrez, David; Chiang, Howard; Dudko, Galina; Filimonov, Yuri; Liu, Guanxiong; Jiang, Chenglong; Balandin, Alexander A.; Lake, Roger; Khitun, Alexander

2017-01-01

We investigated a possible use of the magnonic interferometric switches in multi-valued logic circuits. The switch is a three-terminal device consisting of two spin channels where input, control, and output signals are spin waves. Signal modulation is achieved via the interference between the source and gate spin waves. We report experimental data on a micrometer scale prototype based on the Y3Fe2(FeO4)3 structure. The output characteristics are measured at different angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 13 dB at room temperature. Experimental data are complemented by the theoretical analysis and the results of micro magnetic simulations showing spin wave propagation in a micrometer size magnetic junction. We also present the results of numerical modeling illustrating the operation of a nanometer-size switch consisting of just 20 spins in the source-drain channel. The utilization of spin wave interference as a switching mechanism makes it possible to build nanometer-scale logic gates, and minimize energy per operation, which is limited only by the noise margin. The utilization of phase in addition to amplitude for information encoding offers an innovative route towards multi-state logic circuits. We describe possible implementation of the three-value logic circuits based on the magnonic interferometric switches. The advantages and shortcomings inherent in interferometric switches are also discussed.

Self Calibrating Interferometric Sensor

DEFF Research Database (Denmark)

Sørensen, Henrik Schiøtt

mask. The fabricated micro structures have been electroplated for later injection molding, showing the potential of the MIBD sensor to be mass produced with high reproducibility and sensitivity. In part three MIBD experiments on vital biological systems are described. Label–free binding studies of bio......This thesis deals with the development of an optical sensor based on micro interferometric backscatter detection (MIBD). A price effective, highly sensitive and ready for mass production platform is the goal of this project. The thesis covers three areas. The first part of the thesis deals...

A portfolio of products from the rapid terrain visualization interferometric SAR

Science.gov (United States)

Bickel, Douglas L.; Doerry, Armin W.

2007-04-01

The Rapid Terrain Visualization interferometric synthetic aperture radar was designed and built at Sandia National Laboratories as part of an Advanced Concept Technology Demonstration (ACTD) to "demonstrate the technologies and infrastructure to meet the Army requirement for rapid generation of digital topographic data to support emerging crisis or contingencies." This sensor was built by Sandia National Laboratories for the Joint Programs Sustainment and Development (JPSD) Project Office to provide highly accurate digital elevation models (DEMs) for military and civilian customers, both inside and outside of the United States. The sensor achieved better than HRTe Level IV position accuracy in near real-time. The system was flown on a deHavilland DHC-7 Army aircraft. This paper presents a collection of images and data products from the Rapid Terrain Visualization interferometric synthetic aperture radar. The imagery includes orthorectified images and DEMs from the RTV interferometric SAR radar.

Fundamentals of interferometric gravitational wave detectors

CERN Document Server

Saulson, Peter R

2017-01-01

LIGO's recent discovery of gravitational waves was headline news around the world. Many people will want to understand more about what a gravitational wave is, how LIGO works, and how LIGO functions as a detector of gravitational waves.This book aims to communicate the basic logic of interferometric gravitational wave detectors to students who are new to the field. It assumes that the reader has a basic knowledge of physics, but no special familiarity with gravitational waves, with general relativity, or with the special techniques of experimental physics. All of the necessary ideas are developed in the book.The first edition was published in 1994. Since the book is aimed at explaining the physical ideas behind the design of LIGO, it stands the test of time. For the second edition, an Epilogue has been added; it brings the treatment of technical details up to date, and provides references that would allow a student to become proficient with today's designs.

Leidenfrost drops cooling surfaces: theory and interferometric measurement

OpenAIRE

Van Limbeek, Michiel A. J.; Klein Schaarsberg, Martin H.; Sobac, Benjamin; Rednikov, Alexey; Sun, Chao; Colinet, Pierre; Lohse, Detlef

2017-01-01

When a liquid drop is placed on a highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon is referred to as the Leidenfrost effect. The thermally insulating vapour film results in a severe reduction of the heat transfer rate compared to experiments at lower surface temperatures, where the drop is in direct contact with the solid surface. A commonly made assumption is that this solid surface is isothermal, which is at least questionable for materials of lo...

On the metal-rich surfaces of (16) Psyche and other M-type asteroids from interferometric observations in the thermal infrared

Science.gov (United States)

Delbo, Marco; Matter, A.; Gundlach, B.; Blum, J.

2013-10-01

Asteroids belonging to the spectroscopic M-type exhibit a quasi featureless and moderately red reflectance spectrum and a geometric visible albedo between 0.1 and 0.3. These asteroids were initially thought to be metallic cores of differentiated asteroids that were exposed to space by a catastrophic disruption by impacts. Later, this view has been challenged by the detection of silicates and hydration spectroscopic bands on these bodies. Unveiling the physical properties of the surfaces of these asteroids, and identifying their meteorite analogs is a challenge from remote-sensing observations. Nevertheless, these are crucial problems, important for estimating the number of asteroids that underwent differentiation in the early phases of the formation of our solar system. The thermal inertia is a sensitive indicator for the presence of metal in the regolith on the surfaces of asteroids. We developed a new thermophysical model that allow us to derive the value of the thermal inertia from interferometric observations in the thermal infrared. We report on our investigation of the thermal inertia of M-type asteroids, including the asteroids (16) Psyche, for which we obtained a thermal inertia value anomalously high compared to the thermal inertia values of other asteroids in the same size range. From the thermal inertia and model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles) the regolith grain size is derived.

Automated data reduction for optical interferometric data

International Nuclear Information System (INIS)

Boyd, R.D.; Miller, D.J.; Ghiglia, D.C.

1983-01-01

The potential for significant progress in understanding many transport processes exists through the use of a rapid and automated data reduction process of optical interferometric data. An example involving natural convection in a horizontal annulus is used to demonstrate that the accuracy possible in automated techniques is better than 99.0%

Interferometric full-waveform inversion of time-lapse data

KAUST Repository

Sinha, Mrinal

2017-01-01

surveys. To overcome this challenge, we propose the use of interferometric full waveform inversion (IFWI) for inverting the velocity model from data recorded by baseline and monitor surveys. A known reflector is used as the reference reflector for IFWI

Mission Analysis and Orbit Control of Interferometric Wheel Formation Flying

Science.gov (United States)

Fourcade, J.

Flying satellite in formation requires maintaining the specific relative geometry of the spacecraft with high precision. This requirement raises new problem of orbit control. This paper presents the results of the mission analysis of a low Earth observation system, the interferometric wheel, patented by CNES. This wheel is made up of three receiving spacecraft, which follow an emitting Earth observation radar satellite. The first part of this paper presents trades off which were performed to choose orbital elements of the formation flying which fulfils all constraints. The second part presents orbit positioning strategies including reconfiguration of the wheel to change its size. The last part describes the station keeping of the formation. Two kinds of constraints are imposed by the interferometric system : a constraint on the distance between the wheel and the radar satellite, and constraints on the distance between the wheel satellites. The first constraint is fulfilled with a classical chemical station keeping strategy. The second one is fulfilled using pure passive actuators. Due to the high stability of the relative eccentricity of the formation, only the relative semi major axis had to be controlled. Differential drag due to differential attitude motion was used to control relative altitude. An autonomous orbit controller was developed and tested. The final accuracy is a relative station keeping better than few meters for a wheel size of one kilometer.

Size-selective detection in integrated optical interferometric biosensors

NARCIS (Netherlands)

Mulder, Harmen K P; Ymeti, Aurel; Subramaniam, Vinod; Kanger, Johannes S

2012-01-01

We present a new size-selective detection method for integrated optical interferometric biosensors that can strongly enhance their performance. We demonstrate that by launching multiple wavelengths into a Young interferometer waveguide sensor it is feasible to derive refractive index changes from

Interferometric interrogation of π-phase shifted fiber Bragg grating sensors

Science.gov (United States)

Srivastava, Deepa; Tiwari, Umesh; Das, Bhargab

2018-03-01

Interferometric interrogation technique realized for conventional fiber Bragg grating (FBG) sensors is historically known to offer the highest sensitivity measurements, however, it has not been yet explored for π-phase-shifted FBG (πFBG) sensors. This, we believe, is due to the complex nature of the reflection/transmission spectrum of a πFBG, which cannot be directly used for interferometric interrogation purpose. Therefore, we propose here an innovative as well as simple concept towards this direction, wherein, the transmission spectrum of a πFBG sensor is optically filtered using a specially designed fiber grating. The resulting filtered spectrum retains the entire characteristics of a πFBG sensor and hence the filtered spectrum can be interrogated with interferometric principles. Furthermore, due to the extremely narrow transmission notch of a πFBG sensor, a fiber interferometer can be realized with significantly longer path difference. This leads to substantially enhanced detection limit as compared to sensors based on a regular FBG of similar length. Theoretical analysis demonstrates that high resolution weak dynamic strain measurement down to 4 pε /√{ Hz } is easily achievable. Preliminary experimental results are also presented as proof-of-concept of the proposed interrogation principle.

Interferometric Imaging Directly with Closure Phases and Closure Amplitudes

Science.gov (United States)

Chael, Andrew A.; Johnson, Michael D.; Bouman, Katherine L.; Blackburn, Lindy L.; Akiyama, Kazunori; Narayan, Ramesh

2018-04-01

Interferometric imaging now achieves angular resolutions as fine as ∼10 μas, probing scales that are inaccessible to single telescopes. Traditional synthesis imaging methods require calibrated visibilities; however, interferometric calibration is challenging, especially at high frequencies. Nevertheless, most studies present only a single image of their data after a process of “self-calibration,” an iterative procedure where the initial image and calibration assumptions can significantly influence the final image. We present a method for efficient interferometric imaging directly using only closure amplitudes and closure phases, which are immune to station-based calibration errors. Closure-only imaging provides results that are as noncommittal as possible and allows for reconstructing an image independently from separate amplitude and phase self-calibration. While closure-only imaging eliminates some image information (e.g., the total image flux density and the image centroid), this information can be recovered through a small number of additional constraints. We demonstrate that closure-only imaging can produce high-fidelity results, even for sparse arrays such as the Event Horizon Telescope, and that the resulting images are independent of the level of systematic amplitude error. We apply closure imaging to VLBA and ALMA data and show that it is capable of matching or exceeding the performance of traditional self-calibration and CLEAN for these data sets.

Light-pulse atom interferometric device

Science.gov (United States)

Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash; Jau, Yuan-Yu; Schwindt, Peter; Wheeler, David R.

2016-03-22

An atomic interferometric device useful, e.g., for measuring acceleration or rotation is provided. The device comprises at least one vapor cell containing a Raman-active chemical species, an optical system, and at least one detector. The optical system is conformed to implement a Raman pulse interferometer in which Raman transitions are stimulated in a warm vapor of the Raman-active chemical species. The detector is conformed to detect changes in the populations of different internal states of atoms that have been irradiated by the optical system.

Atom interferometric gravity gradiometer: Disturbance compensation and mobile gradiometry

Science.gov (United States)

Mahadeswaraswamy, Chetan

First ever mobile gravity gradient measurement based on Atom Interferometric sensors has been demonstrated. Mobile gravity gradiometers play a significant role in high accuracy inertial navigation systems in order to distinguish inertial acceleration and acceleration due to gravity. The gravity gradiometer consists of two atom interferometric accelerometers. In each of the accelerometer an ensemble of laser cooled Cesium atoms is dropped and using counter propagating Raman pulses (pi/2-pi-pi/2) the ensemble is split into two states for carrying out atom interferometry. The interferometer phase is proportional to the specific force experienced by the atoms which is a combination of inertial acceleration and acceleration due to gravity. The difference in phase between the two atom interferometric sensors is proportional to gravity gradient if the platform does not undergo any rotational motion. However, any rotational motion of the platform induces spurious gravity gradient measurements. This apparent gravity gradient due to platform rotation is considerably different for an atom interferometric sensor compared to a conventional force rebalance type sensor. The atoms are in free fall and are not influenced by the motion of the case except at the instants of Raman pulses. A model for determining apparent gravity gradient due to rotation of platform was developed and experimentally verified for different frequencies. This transfer function measurement also lead to the development of a new technique for aligning the Raman laser beams with the atom clusters to within 20 mu rad. This gravity gradiometer is situated in a truck for the purpose of undertaking mobile surveys. A disturbance compensation system was designed and built in order to compensate for the rotational disturbances experienced on the floor of a truck. An electric drive system was also designed specifically to be able to move the truck in a uniform motion at very low speeds of about 1cm/s. A 250 x10-9 s-2

Nanohertz gravitational wave searches with interferometric pulsar timing experiments.

Science.gov (United States)

Tinto, Massimo

2011-05-13

We estimate the sensitivity to nano-Hertz gravitational waves of pulsar timing experiments in which two highly stable millisecond pulsars are tracked simultaneously with two neighboring radio telescopes that are referenced to the same timekeeping subsystem (i.e., "the clock"). By taking the difference of the two time-of-arrival residual data streams we can exactly cancel the clock noise in the combined data set, thereby enhancing the sensitivity to gravitational waves. We estimate that, in the band (10(-9)-10(-8))  Hz, this "interferometric" pulsar timing technique can potentially improve the sensitivity to gravitational radiation by almost 2 orders of magnitude over that of single-telescopes. Interferometric pulsar timing experiments could be performed with neighboring pairs of antennas of the NASA's Deep Space Network and the forthcoming large arraying projects.

Low-cost interferometric TDM technology for dynamic sensing applications

Science.gov (United States)

Bush, Jeff; Cekorich, Allen

2004-12-01

A low-cost design approach for Time Division Multiplexed (TDM) fiber-optic interferometric interrogation of multi-channel sensor arrays is presented. This paper describes the evolutionary design process of the subject design. First, the requisite elements of interferometric interrogation are defined for a single channel sensor. The concept is then extended to multi-channel sensor interrogation implementing a TDM multiplex scheme where "traditional" design elements are utilized. The cost of the traditional TDM interrogator is investigated and concluded to be too high for entry into many markets. A new design approach is presented which significantly reduces the cost for TDM interrogation. This new approach, in accordance with the cost objectives, shows promise to bring this technology to within the threshold of commercial acceptance for a wide range of distributed fiber sensing applications.

Development and Evaluation of Science and Technology Education Program Using Interferometric SAR

Science.gov (United States)

Ito, Y.; Ikemitsu, H.; Nango, K.

2016-06-01

This paper proposes a science and technology education program to teach junior high school students to measure terrain changes by using interferometric synthetic aperture radar (SAR). The objectives of the proposed program are to evaluate and use information technology by performing SAR data processing in order to measure ground deformation, and to incorporate an understanding of Earth sciences by analyzing interferometric SAR processing results. To draft the teaching guidance plan for the developed education program, this study considers both science and technology education. The education program was used in a Japanese junior high school. An educational SAR processor developed by the authors and the customized Delft object-oriented radar interferometric software package were employed. Earthquakes as diastrophism events were chosen as practical teaching materials. The selected events indicate clear ground deformation in differential interferograms with high coherence levels. The learners were able to investigate the ground deformations and disasters caused by the events. They interactively used computers and became skilled at recognizing the knowledge and techniques of information technology, and then they evaluated the technology. Based on the results of pre- and post-questionnaire surveys and self-evaluation by the learners, it was clarified that the proposed program was applicable for junior high school education, and the learners recognized the usefulness of Earth observation technology by using interferometric SAR. The usefulness of the teaching materials in the learning activities was also shown through the practical teaching experience.

Benefits and limitations of imaging multiples: Interferometric and resonant migration

KAUST Repository

Guo, Bowen

2015-07-01

The benefits and limitations of imaging multiples are reviewed for interferometric migration and resonant migration. Synthetic and field data examples are used to characterize the effectiveness of the methods.

Benefits and limitations of imaging multiples: Interferometric and resonant migration

KAUST Repository

Guo, Bowen; Yu, Jianhua; Huang, Yunsong; Hanafy, Sherif M.; Schuster, Gerard T.

2015-01-01

The benefits and limitations of imaging multiples are reviewed for interferometric migration and resonant migration. Synthetic and field data examples are used to characterize the effectiveness of the methods.

Rapid interferometric imaging of printed drug laden multilayer structures

DEFF Research Database (Denmark)

Sandler, Niklas; Kassamakov, Ivan; Ehlers, Henrik

2014-01-01

The developments in printing technologies allow fabrication of micron-size nano-layered delivery systems to personal specifications. In this study we fabricated layered polymer structures for drug-delivery into a microfluidic channel and aimed to interferometrically assure their topography...

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.

Improving the performance of interferometric imaging through the use of disturbance feedforward.

Science.gov (United States)

Böhm, Michael; Glück, Martin; Keck, Alexander; Pott, Jörg-Uwe; Sawodny, Oliver

2017-05-01

In this paper, we present a disturbance compensation technique to improve the performance of interferometric imaging for extremely large ground-based telescopes, e.g., the Large Binocular Telescope (LBT), which serves as the application example in this contribution. The most significant disturbance sources at ground-based telescopes are wind-induced mechanical vibrations in the range of 8-60 Hz. Traditionally, their optical effect is eliminated by feedback systems, such as the adaptive optics control loop combined with a fringe tracking system within the interferometric instrument. In this paper, accelerometers are used to measure the vibrations. These measurements are used to estimate the motion of the mirrors, i.e., tip, tilt and piston, with a dynamic estimator. Additional delay compensation methods are presented to cancel sensor network delays and actuator input delays, improving the estimation result even more, particularly at higher frequencies. Because various instruments benefit from the implementation of telescope vibration mitigation, the estimator is implemented as a separate, independent software on the telescope, publishing the estimated values via multicast on the telescope's ethernet. Every client capable of using and correcting the estimated disturbances can subscribe and use these values in a feedforward for its compensation device, e.g., the deformable mirror, the piston mirror of LINC-NIRVANA, or the fast path length corrector of the Large Binocular Telescope Interferometer. This easy-to-use approach eventually leveraged the presented technology for interferometric use at the LBT and now significantly improves the sky coverage, performance, and operational robustness of interferometric imaging on a regular basis.

Performance Analysis of Measurement Inaccuracies of IMU/GPS on Airborne Repeat-pass Interferometric SAR in the Presence of Squint

Directory of Open Access Journals (Sweden)

Deng Yuan

2014-08-01

Full Text Available In the MOtion COmpensation (MOCO approach to airborne repeat-pass interferometric Synthetic Aperture Radar (SAR based on motion measurement data, the measurement inaccuracies of Inertial Measurement Unit/Global Positioning System (IMU/GPS and the positioning errors of the target, which may contribute to the residual uncompensated motion errors, affect the imaging result and interferometric measurement. Considering the effects of the two types of error, this paper builds a mathematical model of residual motion errors in presence of squint, and analyzes the effects on the residual motion errors induced by the measurement inaccuracies of IMU/GPS and the positioning errors of the target. In particular, the effects of various measurement inaccuracies of IMU/GPS on interferometric SAR image quality, interferometric phase, and digital elevation model precision are disscussed. Moreover, the paper quantitatively researches the effects of residual motion errors on airborne repeat-pass interferometric SAR through theoretical and simulated analyses and provides theoretical bases for system design and signal processing.

Radio Interferometric Research of Ionosphere by Signals of Space Satellites

Directory of Open Access Journals (Sweden)

Dugin N.

2013-03-01

Full Text Available Since 2012, the Radiophysical Research Institute and the Lobachevsky State University at Nizhny Novgorod, Russia and the Ventspils International Radio Astronomy Centre at Irbene, Latvia are making radio interferometric experiments on study of ionosphere parameters in a quiet (natural state of medium and research of artificial turbulence of the ionosphere, heated by the emission from the SURA facility. Remote diagnostics of the ionosphere is implemented using a method of radio sounding by signals of navigation satellites in combination with the Very Long Baseline Interferometry (VLBI method. As a result of spectral and correlation analysis, interferometric responses of the two-element (RRI–UNN and three-element (RRI–UNN–Irbene interferometers were received by observations of 12 satellites of the navigation systems GLONASS and GPS. Here the first results are reported.

Linear projection of technical noise for interferometric gravitational-wave detectors

International Nuclear Information System (INIS)

Smith, J R; Ajith, P; Grote, H; Hewitson, M; Hild, S; Lueck, H; Strain, K A; Willke, B; Hough, J; Danzmann, K

2006-01-01

An international network of interferometric gravitational-wave detectors is now in operation, and has entered a period of intense commissioning focused on bringing the instruments to their theoretical sensitivity limits. To expedite this process, noise analysis techniques have been developed by the groups associated with each instrument. We present methods of noise analysis that were developed and utilized for the commissioning of the GEO 600 detector. The focal point of this paper is a technique called noise projection that is used to determine the levels of contribution of various noise sources to the detector output. Example applications of this method to control loops typical of those employed in an interferometric GW detector are presented. Possible extensions of noise projections, including technical noise subtraction and gravitational-wave vetoes are also discussed

SAR Interferogram Filtering of Shearlet Domain Based on Interferometric Phase Statistics

Directory of Open Access Journals (Sweden)

Yonghong He

2017-02-01

Full Text Available This paper presents a new filtering approach for Synthetic Aperture Radar (SAR interferometric phase noise reduction in the shearlet domain, depending on the coherent statistical characteristics. Shearlets provide a multidirectional and multiscale decomposition that have advantages over wavelet filtering methods when dealing with noisy phase fringes. Phase noise in SAR interferograms is directly related to the interferometric coherence and the look number of the interferogram. Therefore, an optimal interferogram filter should incorporate information from both of them. The proposed method combines the phase noise standard deviation with the shearlet transform. Experimental results show that the proposed method can reduce the interferogram noise while maintaining the spatial resolution, especially in areas with low coherence.

Estimating snow water equivalent (SWE) using interferometric synthetic aperture radar (InSAR)

Science.gov (United States)

Deeb, Elias J.

Since the early 1990s, radar interferometry and interferometric synthetic aperture radar (InSAR) have been used extensively to measure changes in the Earth's surface. Previous research has presented theory for estimating snow properties, including potential for snow water equivalent (SWE) retrieval, using InSAR. The motivation behind using remote sensing to estimate SWE is to provide a more complete, continuous set of "observations" to assist in water management operations, climate change studies, and flood hazard forecasting. The research presented here primarily investigates the feasibility of using the InSAR technique at two different wavelengths (C-Band and L-Band) for SWE retrieval of dry snow within the Kuparuk watershed, North Slope, Alaska. Estimating snow distribution around meteorological towers on the coastal plain using a three-day repeat orbit of C-Band InSAR data was successful (Chapter 2). A longer wavelength L-band SAR is evaluated for SWE retrievals (Chapter 3) showing the ability to resolve larger snow accumulation events over a longer period of time. Comparisons of InSAR estimates and late spring manual sampling of SWE show a R2 = 0.61 when a coherence threshold is used to eliminate noisy SAR data. Qualitative comparisons with a high resolution digital elevation model (DEM) highlight areas of scour on windward slopes and areas of deposition on leeward slopes. When compared to a mid-winter transect of manually sampled snow depths, the InSAR SWE estimates yield a RMSE of 2.21cm when a bulk snow density is used and corrections for bracketing the satellite acquisition timing is performed. In an effort to validate the interaction of radar waves with a snowpack, the importance of the "dry snow" assumption for the estimation of SWE using InSAR is tested with an experiment in Little Cottonwood Canyon, Alta, Utah (Chapter 5). Snow wetness is shown to have a significant effect on the velocity of propagation within the snowpack. Despite the radar

Calibration of the modulation transfer function of surface profilometers with binary pseudo-random test standards: expanding the application range

International Nuclear Information System (INIS)

Yashchuk, Valeriy V.; Anderson, Erik H.; Barber, Samuel K.; Bouet, Nathalie; Cambie, Rossana; Conley, Raymond; McKinney, Wayne R.; Takacs, Peter Z.; Voronov, Dmitriy L.

2011-01-01

A modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays (Proc. SPIE 7077-7 (2007), Opt. Eng. 47, 073602 (2008)) has been proven to be an effective MTF calibration method for a number of interferometric microscopes and a scatterometer (Nucl. Instr. and Meth. A616, 172 (2010)). Here we report on a further expansion of the application range of the method. We describe the MTF calibration of a 6 inch phase shifting Fizeau interferometer. Beyond providing a direct measurement of the interferometer's MTF, tests with a BPR array surface have revealed an asymmetry in the instrument's data processing algorithm that fundamentally limits its bandwidth. Moreover, the tests have illustrated the effects of the instrument's detrending and filtering procedures on power spectral density measurements. The details of the development of a BPR test sample suitable for calibration of scanning and transmission electron microscopes are also presented. Such a test sample is realized as a multilayer structure with the layer thicknesses of two materials corresponding to BPR sequence. The investigations confirm the universal character of the method that makes it applicable to a large variety of metrology instrumentation with spatial wavelength bandwidths from a few nanometers to hundreds of millimeters.

Microgravity vertical gradient measurement in the site of VIRGO interferometric antenna (Pisa plain, Italy

Directory of Open Access Journals (Sweden)

F. Fidecaro

2008-06-01

Full Text Available The site of the European Gravitational Observatory (EGO located in the countryside near Pisa (Tuscany, Italy was investigated by a microgravity vertical gradient (MVG survey. The EGO site houses the VIRGO interferometric antenna for gravitational waves detection. The microgravity survey aims to highlight the gravity anomalies of high-frequency related to more superficial geological sources in order to obtain a detailed model of the lithologic setting of the VIRGO site, that will allow an estimate of the noise induced by seismic waves and by Newtonian interference. This paper presents the results of the gradiometric survey of 2006 in the area of the interferometric antenna. MVG measurements allow us to enhance the high frequency signal strongly associated with the shallow structures. The gradient gravity map shows a main negative pattern that seems related to the trending of the high density layer of gravel that was evidenced in geotechnical drillings executed along the orthogonal arms during the construction of the VIRGO complex. Calibrating the relationship between the vertical gradient and the depth of the gravel interface we have computed a model of gravity gradient for the whole VIRGO site, defining the 3D distribution of the top surface of this layer. This latter shows a NE-SW negative pattern that may represent a palaeo-bed alluvial of the Serchio from the Bientina River system.

All-optical 40 Gbit/s compact integrated interferometric wavelength converter

DEFF Research Database (Denmark)

Jørgensen, Carsten; Danielsen, Søren Lykke; Hansen, Peter Bukhave

1997-01-01

An interferometric Michelson wavelength converter is presented that combines a speed-optimized semiconductor optical amplifier technology with the benefits of the integrated interferometer showing 40-Gbit/s wavelength conversion. The optimized wavelength converter demonstrates noninverted converted...

Advanced Virgo: a second-generation interferometric gravitational wave detector

NARCIS (Netherlands)

Acernese, F.; Bulten, H.J.; Rabeling, D.S.; van den Brand, J.F.J.

2015-01-01

Advanced Virgo is the project to upgrade the Virgo interferometric detector of gravitational waves, with the aim of increasing the number of observable galaxies (and thus the detection rate) by three orders of magnitude. The project is now in an advanced construction phase and the assembly and

Interferometric optical fiber microcantilever beam biosensor

Science.gov (United States)

Wavering, Thomas A.; Meller, Scott A.; Evans, Mishell K.; Pennington, Charles; Jones, Mark E.; VanTassell, Roger; Murphy, Kent A.; Velander, William H.; Valdes, E.

2000-12-01

With the proliferation of biological weapons, the outbreak of food poisoning occurrences, and the spread of antibiotic resistant strains of pathogenic bacteria, the demand has arisen for portable systems capable of rapid, specific, and quantitative target detection. The ability to detect minute quantities of targets will provide the means to quickly assess a health hazardous situation so that the appropriate response can be orchestrated. Conventional test results generally require hours or even several days to be reported, and there is no change for real-time feedback. An interferometric optical fiber microcantilever beam biosensor has successfully demonstrated real time detection of target molecules. The microcantilever biosensor effectively combines advanced technology from silicon micromachining, optical fiber sensor, and biochemistry to create a novel detection device. This approach utilizes affinity coatings on micromachiend cantilever beams to attract target molecules. The presence of the target molecule causes bending in the cantilever beam, which is monitored using an optical displacement system. Dose-response trials have shown measured responses at nanogram/ml concentrations of target molecules. Sensitivity is expected to extend from the nanogram to the picogram range of total captured mass as the microcantilever sensors are optimized.

Pump-induced optical distortions in disk amplifier modules: holographic and interferometric measurements

International Nuclear Information System (INIS)

Linford, G.J.; Chau, H.H.; Glaze, J.A.; Layne, C.B.; Rainer, F.

1975-01-01

Interferometric measurements have been made of the optical distortions induced in laser disk amplifiers during the flashlamp pumping pulse. Both conventional interferometric methods and the techniques of double exposure holographic interferometry were used to identify four major sources of pump-induced optical distortions: subsonic intrusion of hot gas (traced to leakage of atmospheric oxygen into the amplifier), microexplosions of dust particles, thermally induced optical distortions in the glass disks, and gaseous optical distortion effects caused by turbulent flow of the purging nitrogen gas supply used within the laser amplifier head. Methods for reducing or eliminating the effects of each of these optical distortions are described

Interferometric architectures based All-Optical logic design methods and their implementations

Science.gov (United States)

Singh, Karamdeep; Kaur, Gurmeet

2015-06-01

All-Optical Signal Processing is an emerging technology which can avoid costly Optical-electronic-optical (O-E-O) conversions which are usually compulsory in traditional Electronic Signal Processing systems, thus greatly enhancing operating bit rate with some added advantages such as electro-magnetic interference immunity and low power consumption etc. In order to implement complex signal processing tasks All-Optical logic gates are required as backbone elements. This review describes the advances in the field of All-Optical logic design methods based on interferometric architectures such as Mach-Zehnder Interferometer (MZI), Sagnac Interferometers and Ultrafast Non-Linear Interferometer (UNI). All-Optical logic implementations for realization of arithmetic and signal processing applications based on each interferometric arrangement are also presented in a categorized manner.

The Impact of Inter-Modulation Components on Interferometric GNSS-Reflectometry

Directory of Open Access Journals (Sweden)

Weiqiang Li

2016-12-01

Full Text Available The interferometric Global Navigation Satellite System Reflectometry (iGNSS-R exploits the full spectrum of the transmitted GNSS signal to improve the ranging performance for sea surface height applications. The Inter-Modulation (IM component of the GNSS signals is an additional component that keeps the power envelope of the composite signals constant. This extra component has been neglected in previous studies on iGNSS-R, in both modelling and instrumentation. This letter takes the GPS L1 signal as an example to analyse the impact of the IM component on iGNSS-R ocean altimetry, including signal-to-noise ratio, the altimetric sensitivity and the final altimetric precision. Analytical results show that previous estimates of the final altimetric precision were underestimated by a factor of 1 . 5 ∼ 1 . 7 due to the negligence of the IM component, which should be taken into account in proper design of the future spaceborne iGNSS-R altimetry missions.

In situ non-destructive measurement of biofilm thickness and topology in an interferometric optical microscope

Energy Technology Data Exchange (ETDEWEB)

Larimer, Curtis [Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50 Richland WA 99354 USA; Suter, Jonathan D. [Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50 Richland WA 99354 USA; Bonheyo, George [Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50 Richland WA 99354 USA; Addleman, Raymond Shane [Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50 Richland WA 99354 USA

2016-03-15

Biofilms are ubiquitous and deleteriously impact a wide range of industrial processes, medical and dental health issues, and environmental problems such as transport of invasive species and the fuel efficiency of ocean going vessels. Biofilms are difficult to characterize when fully hydrated, especially in a non-destructive manner, because of their soft structure and water-like bulk properties. Herein we describe a non-destructive high resolution method of measuring and monitoring the thickness and topology of live biofilms of using white light interferometric optical microscopy. Using this technique, surface morphology, surface roughness, and biofilm thickness can be measured non-destructively and with high resolution as a function of time without disruption of the biofilm activity and processes. The thickness and surface topology of a P. putida biofilm were monitored growing from initial colonization to a mature biofilm. Typical bacterial growth curves were observed. Increase in surface roughness was a leading indicator of biofilm growth.

Surface-specific additive manufacturing test artefacts

Science.gov (United States)

Townsend, Andrew; Racasan, Radu; Blunt, Liam

2018-06-01

Many test artefact designs have been proposed for use with additive manufacturing (AM) systems. These test artefacts have primarily been designed for the evaluation of AM form and dimensional performance. A series of surface-specific measurement test artefacts designed for use in the verification of AM manufacturing processes are proposed here. Surface-specific test artefacts can be made more compact because they do not require the large dimensions needed for accurate dimensional and form measurements. The series of three test artefacts are designed to provide comprehensive information pertaining to the manufactured surface. Measurement possibilities include deviation analysis, surface texture parameter data generation, sub-surface analysis, layer step analysis and build resolution comparison. The test artefacts are designed to provide easy access for measurement using conventional surface measurement techniques, for example, focus variation microscopy, stylus profilometry, confocal microscopy and scanning electron microscopy. Additionally, the test artefacts may be simply visually inspected as a comparative tool, giving a fast indication of process variation between builds. The three test artefacts are small enough to be included in every build and include built-in manufacturing traceability information, making them a convenient physical record of the build.

Mid-infrared interferometric variability of DG Tauri: Implications for the inner-disk structure

Science.gov (United States)

Varga, J.; Gabányi, K. É.; Ábrahám, P.; Chen, L.; Kóspál, Á.; Menu, J.; Ratzka, Th.; van Boekel, R.; Dullemond, C. P.; Henning, Th.; Jaffe, W.; Juhász, A.; Moór, A.; Mosoni, L.; Sipos, N.

2017-08-01

Context. DG Tau is a low-mass pre-main sequence star, whose strongly accreting protoplanetary disk exhibits a so-far enigmatic behavior: its mid-infrared thermal emission is strongly time-variable, even turning the 10 μm silicate feature from emission to absorption temporarily. Aims: We look for the reason for the spectral variability at high spatial resolution and at multiple epochs. Methods: Infrared interferometry can spatially resolve the thermal emission of the circumstellar disk, also giving information about dust processing. We study the temporal variability of the mid-infrared interferometric signal, observed with the VLTI/MIDI instrument at six epochs between 2011 and 2014. We fit a geometric disk model to the observed interferometric signal to obtain spatial information about the disk. We also model the mid-infrared spectra by template fitting to characterize the profile and time dependence of the silicate emission. We use physically motivated radiative transfer modeling to interpret the mid-infrared interferometric spectra. Results: The inner disk (r 1-3 au) spectra show a crystalline silicate feature in emission, similar to the spectra of comet Hale-Bopp. The striking difference between the inner and outer disk spectral feature is highly unusual among T Tauri stars. The mid-infrared variability is dominated by the outer disk. The strength of the silicate feature changed by more than a factor of two. Between 2011 and 2014 the half-light radius of the mid-infrared-emitting region decreased from 1.15 to 0.7 au. Conclusions: For the origin of the absorption we discuss four possible explanations: a cold obscuring envelope, an accretion heated inner disk, a temperature inversion on the disk surface and a misaligned inner geometry. The silicate emission in the outer disk can be explained by dusty material high above the disk plane, whose mass can change with time, possibly due to turbulence in the disk. Based on observations made with the ESO Very Large

Modeling and Validation of Performance Limitations for the Optimal Design of Interferometric and Intensity-Modulated Fiber Optic Displacement Sensors

Energy Technology Data Exchange (ETDEWEB)

Moro, Erik A. [Los Alamos National Laboratory

2012-06-07

Optical fiber sensors offer advantages over traditional electromechanical sensors, making them particularly well-suited for certain measurement applications. Generally speaking, optical fiber sensors respond to a desired measurand through modulation of an optical signal's intensity, phase, or wavelength. Practically, non-contacting fiber optic displacement sensors are limited to intensity-modulated and interferometric (or phase-modulated) methodologies. Intensity-modulated fiber optic displacement sensors relate target displacement to a power measurement. The simplest intensity-modulated sensor architectures are not robust to environmental and hardware fluctuations, since such variability may cause changes in the measured power level that falsely indicate target displacement. Differential intensity-modulated sensors have been implemented, offering robustness to such intensity fluctuations, and the speed of these sensors is limited only by the combined speed of the photodetection hardware and the data acquisition system (kHz-MHz). The primary disadvantages of intensity-modulated sensing are the relatively low accuracy (?m-mm for low-power sensors) and the lack of robustness, which consequently must be designed, often with great difficulty, into the sensor's architecture. White light interferometric displacement sensors, on the other hand, offer increased accuracy and robustness. Unlike their monochromatic-interferometer counterparts, white light interferometric sensors offer absolute, unambiguous displacement measurements over large displacement ranges (cm for low-power, 5 mW, sources), necessitating no initial calibration, and requiring no environmental or feedback control. The primary disadvantage of white light interferometric displacement sensors is that their utility in dynamic testing scenarios is limited, both by hardware bandwidth and by their inherent high-sensitivity to Doppler-effects. The decision of whether to use either an intensity

Super-Virtual Refraction Interferometric Redatuming: Enhancing the Refracted Energy

KAUST Repository

Aldawood, Ali

2012-02-26

onshore seismic data processing. Refraction tomography is becoming a common way to estimate an accurate near surface velocity model. One of the problems with refraction tomography is the low signal to noise ration in far offset data. To improve, we propose using super-virtual refraction interferometry to enhance the weak energy at far offsets. We use Interferometric Green\\'s functions to redatum sources by cross-correlating two traces recorded at receiver stations, A and B, from a source at location W. The result is a redatumed trace with a virtual source at A and a receiver at B, which can also be obtained by correlating two traces recorded at A and B from different shots. Stacking them would enhance the signal-to-noise ratio of this "virtual" trace. We next augment redatuming with convolution and stacking. The trace recorded at B from a virtual source at A is convolved with the original trace recorded at A from a source at W. The result is a "super-virtual" trace at B in the far-offset from a source at W. Stacking N traces gives a vN-improvement. We applied our method to noisy synthetic and field data recorded over a complex near-surface and we could pick more traces at far offsets. It was possible to accommodate more picks resulting in a better subsurface coverage

Super-Virtual Refraction Interferometric Redatuming: Enhancing the Refracted Energy

KAUST Repository

Aldawood, Ali; Alshuhail, Abdulrahman Abdullatif Abdulrahman; Hanafy, Sherif

2012-01-01

onshore seismic data processing. Refraction tomography is becoming a common way to estimate an accurate near surface velocity model. One of the problems with refraction tomography is the low signal to noise ration in far offset data. To improve, we propose using super-virtual refraction interferometry to enhance the weak energy at far offsets. We use Interferometric Green's functions to redatum sources by cross-correlating two traces recorded at receiver stations, A and B, from a source at location W. The result is a redatumed trace with a virtual source at A and a receiver at B, which can also be obtained by correlating two traces recorded at A and B from different shots. Stacking them would enhance the signal-to-noise ratio of this "virtual" trace. We next augment redatuming with convolution and stacking. The trace recorded at B from a virtual source at A is convolved with the original trace recorded at A from a source at W. The result is a "super-virtual" trace at B in the far-offset from a source at W. Stacking N traces gives a vN-improvement. We applied our method to noisy synthetic and field data recorded over a complex near-surface and we could pick more traces at far offsets. It was possible to accommodate more picks resulting in a better subsurface coverage

Statistical analysis of laser-interferometric detector Dylkin-1 data and data on seismic activity

International Nuclear Information System (INIS)

Kirillov, R S; Bochkarev, V V; Dulkyn, Academy of Sciences of the Republic of Tatarstan (Russian Federation))" data-affiliation=" (Scientific Center of Gravitational-Wave Research Dulkyn, Academy of Sciences of the Republic of Tatarstan (Russian Federation))" >Skochilov, A F

2014-01-01

This work presents statistical analysis of data collected from laser interferometric detector ''Dylkin-1'' and nearby seismic stations. The final goal of Dylkin project consists in creating detector of theoretically predicted gravitational waves produced by binary relativistic astrophysical objects. Currently, works are underway to improve sensitivity of detector by 2-3 orders. The goals of this research were to test isolation of detector from noise caused by seismic waves and to find out whether it is sensitive to variations in the gradient of gravitational potential (acceleration of free fall) caused by free Earth oscillations. Noise isolation has been tested by comparing energy of signals during significant seismic events. Sensitivity to variations in acceleration of free fall has been tested by means of cross-spectral analysis

Precision interferometric measurement of right angles with the aid of an etalon

International Nuclear Information System (INIS)

Oreb, B.; Walsh, C.; Leistner, A.

2000-01-01

Full text: An interferometric set up has been developed to measure right angles between faces of components such as prisms or cubes, to sub arc second resolution. The component to be measured is placed inside an air spaced etalon and the right angle is measured by a Fizeau interferometer with respect to a transmission reference flat. The etalon consists of two precision glass flats which are aligned to be parallel by optically contacting these to a cylindrical Zerodur sleeve having flat and parallel ends. A circular cut out in the cylindrical sleeve is made to allow the test component and the light from the interferometer to enter the etalon. The phase difference in the two halves of the interferogram corresponding to the two sides of the test component is a measure of the angle deviation from 90 deg

Robust sparse image reconstruction of radio interferometric observations with PURIFY

Science.gov (United States)

Pratley, Luke; McEwen, Jason D.; d'Avezac, Mayeul; Carrillo, Rafael E.; Onose, Alexandru; Wiaux, Yves

2018-01-01

Next-generation radio interferometers, such as the Square Kilometre Array, will revolutionize our understanding of the Universe through their unprecedented sensitivity and resolution. However, to realize these goals significant challenges in image and data processing need to be overcome. The standard methods in radio interferometry for reconstructing images, such as CLEAN, have served the community well over the last few decades and have survived largely because they are pragmatic. However, they produce reconstructed interferometric images that are limited in quality and scalability for big data. In this work, we apply and evaluate alternative interferometric reconstruction methods that make use of state-of-the-art sparse image reconstruction algorithms motivated by compressive sensing, which have been implemented in the PURIFY software package. In particular, we implement and apply the proximal alternating direction method of multipliers algorithm presented in a recent article. First, we assess the impact of the interpolation kernel used to perform gridding and degridding on sparse image reconstruction. We find that the Kaiser-Bessel interpolation kernel performs as well as prolate spheroidal wave functions while providing a computational saving and an analytic form. Secondly, we apply PURIFY to real interferometric observations from the Very Large Array and the Australia Telescope Compact Array and find that images recovered by PURIFY are of higher quality than those recovered by CLEAN. Thirdly, we discuss how PURIFY reconstructions exhibit additional advantages over those recovered by CLEAN. The latest version of PURIFY, with developments presented in this work, is made publicly available.

3D shape measurements with a single interferometric sensor for in-situ lathe monitoring

Science.gov (United States)

Kuschmierz, R.; Huang, Y.; Czarske, J.; Metschke, S.; Löffler, F.; Fischer, A.

2015-05-01

Temperature drifts, tool deterioration, unknown vibrations as well as spindle play are major effects which decrease the achievable precision of computerized numerically controlled (CNC) lathes and lead to shape deviations between the processed work pieces. Since currently no measurement system exist for fast, precise and in-situ 3d shape monitoring with keyhole access, much effort has to be made to simulate and compensate these effects. Therefore we introduce an optical interferometric sensor for absolute 3d shape measurements, which was integrated into a working lathe. According to the spindle rotational speed, a measurement rate of 2,500 Hz was achieved. In-situ absolute shape, surface profile and vibration measurements are presented. While thermal drifts of the sensor led to errors of several mµm for the absolute shape, reference measurements with a coordinate machine show, that the surface profile could be measured with an uncertainty below one micron. Additionally, the spindle play of 0.8 µm was measured with the sensor.

Sea ice local surface topography from single-pass satellite InSAR measurements: a feasibility study

Directory of Open Access Journals (Sweden)

W. Dierking

2017-08-01

Full Text Available Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere–ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that, theoretically, surface height variations can be retrieved with relative errors  ≤  0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.

Advanced Interferometric Synthetic Aperture Imaging Radar (InSAR) for Dune Mapping

Science.gov (United States)

Havivi, Shiran; Amir, Doron; Schvartzman, Ilan; August, Yitzhak; Mamman, Shimrit; Rotman, Stanely R.; Blumberg, Dan G.

2016-04-01

Aeolian morphologies are formed in the presence of sufficient wind energy and available lose particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970s, remote sensing imagery, both optical and radar, have been used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two or more images. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR methods. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This work aims to demonstrate how interferometric decorrelation can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the coherence change detection method was used, in order to identify dune stability or instability and the dune activity level. The Nitzanim-Ashdod coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of

Interferometric measurements of dry mass content in nuclei and cytoplasm in the life cycle of antheridial filaments cells of Chara vulgaris L. in their successive developmental stages

Directory of Open Access Journals (Sweden)

Hanna Kuran

2015-01-01

Full Text Available Interferometric measurements of the nucleus and cytoplasm dry mass during interphase in the successive stages of development of antheridial filaments of Chara vulgaris demonstrated that the dry mass and surface area of cell nuclei double in size in each of the successive generations of the filaments, whereas neither the surface nor the dry mass of the cytoplasm increase in such proportion in the same period. In the successive stages of development of the antheridial filaments the dry mass and surface area of the nuclei and cytoplasm gradually diminish.

Interferometric capability for the Magellan Project

Science.gov (United States)

Carleton, Nathaniel P.; Traub, Wesley A.; Angel, J. Roger P.

1998-07-01

The Magellan Project is building two 6.5-m telescopes, 60 m apart, at the Las Campanas Observatory in Chile. There are on-going plans to combine the beams of the two main telescopes, and of smaller auxiliary telescopes, for interferometric measurements. In this paper we consider the array of auxiliary telescopes as a stand-alone instrument, recognizing that it will operate as such for some large fraction of the time. Our interest is sharpened by the availability of six 1.8-m optical systems, retired from the Smithsonian-Arizona Multiple-Mirror Telescope in preparation for the installation of a single-mirror 6.5-m system. We have completed a design for a 1.8-m telescope, in which the MMT components are supported on a proven tripod mount. The optics-support uses steel for stiffness, and low-thermal- expansion rods for passive stability. This array will be a powerful tool for the investigation of stellar limb darkening, surface features, and changes of diameter in pulsations, as well as dust disks, shells, and binary companions. The 1.8-m telescopes on good sites such as Magellan's should be able to operate at full aperture for interferometry at 2.2 micrometers . They should therefore be able to reach to magnitude K equals 10 or so, and thus to cover substantial samples of both main-sequence and pre-main- sequence stars, and of fully evolved stars as well.

Multi-Wavelength Interferometric Observations of YSO Disks

Science.gov (United States)

Ragland, Sam; Akeson, R.; Armandroff, T.; Colavita, M.; Cotton, W.; Danchi, W.; Hillenbrand, L.; Millan-Gabet, R.; Ridgway, S. T.; Traub, W.; Wizinowich, P.

2010-01-01

We initiated a multi-color interferometric study of YSO disks in the K, L and N bands using the Keck Interferometer. The initial results on two Herbig Ae/Be stars will be presented. Our observations are sensitive to the radial distribution of temperature in the inner region of the YSO disks. The geometric models show that the apparent size increases linearly with wavelength, suggesting that the disk is extended with a temperature gradient. We will discuss our results in conjunction with the previous measurements of these targets.

The linearized inversion of the generalized interferometric multiple imaging

KAUST Repository

Aldawood, Ali

2016-09-06

The generalized interferometric multiple imaging (GIMI) procedure can be used to image duplex waves and other higher order internal multiples. Imaging duplex waves could help illuminate subsurface zones that are not easily illuminated by primaries such as vertical and nearly vertical fault planes, and salt flanks. To image first-order internal multiple, the GIMI framework consists of three datuming steps, followed by applying the zero-lag cross-correlation imaging condition. However, the standard GIMI procedure yields migrated images that suffer from low spatial resolution, migration artifacts, and cross-talk noise. To alleviate these problems, we propose a least-squares GIMI framework in which we formulate the first two steps as a linearized inversion problem when imaging first-order internal multiples. Tests on synthetic datasets demonstrate the ability to localize subsurface scatterers in their true positions, and delineate a vertical fault plane using the proposed method. We, also, demonstrate the robustness of the proposed framework when imaging the scatterers or the vertical fault plane with erroneous migration velocities.

The rapid terrain visualization interferometric synthetic aperture radar sensor

Science.gov (United States)

Graham, Robert H.; Bickel, Douglas L.; Hensley, William H.

2003-11-01

The Rapid Terrain Visualization interferometric synthetic aperture radar was designed and built at Sandia National Laboratories as part of an Advanced Concept Technology Demonstration (ACTD) to "demonstrate the technologies and infrastructure to meet the Army requirement for rapid generation of digital topographic data to support emerging crisis or contingencies." This sensor is currently being operated by Sandia National Laboratories for the Joint Precision Strike Demonstration (JPSD) Project Office to provide highly accurate digital elevation models (DEMs) for military and civilian customers, both inside and outside of the United States. The sensor achieves better than DTED Level IV position accuracy in near real-time. The system is being flown on a deHavilland DHC-7 Army aircraft. This paper outlines some of the technologies used in the design of the system, discusses the performance, and will discuss operational issues. In addition, we will show results from recent flight tests, including high accuracy maps taken of the San Diego area.

A Differential Polarized Light Interferometric System For Measuring Flatness Of Magnetic Disks

Science.gov (United States)

Jia, Wang; Da-Cheng, Li; Ye, Chen; Ling, Du; Mang, Cao

1987-01-01

A kind of differential polarizdd laser interferometric system for non-contact and dynamic measurement of the flatness characteristic of magnetic disks without the effect of the axial vibration is described in this papper.

Cross-calibration of interferometric SAR data

DEFF Research Database (Denmark)

Dall, Jørgen

2003-01-01

Generation of digital elevation models from interferometric synthetic aperture radar (SAR) data is a well established technique. Achieving a high geometric fidelity calls for a calibration accounting for inaccurate navigation data and system parameters as well as system imperfections. Fully...... automated calibration techniques are preferable, especially for operational mapping. The author presents one such technique, called cross-calibration. Though developed for single-pass interferometry, it may be applicable to multi-pass interferometry, too. Cross-calibration requires stability during mapping...... ground control point is often needed. The paper presents the principles and mathematics of the cross-calibration technique and illustrates its successful application to EMISAR data....

Leidenfrost drops cooling surfaces: theory and interferometric measurement

NARCIS (Netherlands)

Van Limbeek, Michiel A. J.; Klein Schaarsberg, Martin H.; Sobac, Benjamin; Rednikov, Alexey; Sun, Chao; Colinet, Pierre; Lohse, Detlef

2017-01-01

When a liquid drop is placed on a highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon is referred to as the Leidenfrost effect. The thermally insulating vapour film results in a severe reduction of the heat transfer rate compared to experiments at lower

Astigmatism compensation in mode-cleaner cavities for the next generation of gravitational wave interferometric detectors

Energy Technology Data Exchange (ETDEWEB)

Barriga, Pablo J. [School of Physics, University of Western Australia, Crawley, WA 6009 (Australia)]. E-mail: pbarriga@cyllene.uwa.edu.au; Zhao Chunnong [School of Physics, University of Western Australia, Crawley, WA 6009 (Australia); Blair, David G. [School of Physics, University of Western Australia, Crawley, WA 6009 (Australia)

2005-06-06

Interferometric gravitational wave detectors use triangular ring cavities to filter spatial and frequency instabilities from the input laser beam. The next generation of interferometric detectors will use high laser power and greatly increased circulating power inside the cavities. The increased power inside the cavities increases thermal effects in their mirrors. The triangular configuration of conventional mode-cleaners creates an intrinsic astigmatism that can be corrected by using the thermal effects to advantage. In this Letter we show that an astigmatism free output beam can be created if the design parameters are correctly chosen.

Astigmatism compensation in mode-cleaner cavities for the next generation of gravitational wave interferometric detectors

International Nuclear Information System (INIS)

Barriga, Pablo J.; Zhao Chunnong; Blair, David G.

2005-01-01

Interferometric gravitational wave detectors use triangular ring cavities to filter spatial and frequency instabilities from the input laser beam. The next generation of interferometric detectors will use high laser power and greatly increased circulating power inside the cavities. The increased power inside the cavities increases thermal effects in their mirrors. The triangular configuration of conventional mode-cleaners creates an intrinsic astigmatism that can be corrected by using the thermal effects to advantage. In this Letter we show that an astigmatism free output beam can be created if the design parameters are correctly chosen

Super-virtual Interferometric Separation and Enhancement of Back-scattered Surface Waves

KAUST Repository

Guo, Bowen; Hanafy, Sherif; Schuster, Gerard T.

2015-01-01

Back-scattered surface waves can be migrated to detect near-surface reflectors with steep dips. A robust surface-wave migration requires the prior separation of the back-scattered surface-wave events from the data. This separation is often difficult

Versatile generation of optical vector fields and vector beams using a non-interferometric approach.

Science.gov (United States)

Tripathi, Santosh; Toussaint, Kimani C

2012-05-07

We present a versatile, non-interferometric method for generating vector fields and vector beams which can produce all the states of polarization represented on a higher-order Poincaré sphere. The versatility and non-interferometric nature of this method is expected to enable exploration of various exotic properties of vector fields and vector beams. To illustrate this, we study the propagation properties of some vector fields and find that, in general, propagation alters both their intensity and polarization distribution, and more interestingly, converts some vector fields into vector beams. In the article, we also suggest a modified Jones vector formalism to represent vector fields and vector beams.

Ground based interferometric radar initial look at Longview, Blue Springs, Tuttle Creek, and Milford Dams

Science.gov (United States)

Deng, Huazeng

Measuring millimeter and smaller deformation has been demonstrated in the literature using RADAR. To address in part the limitations in current commercial satellite-based SAR datasets, a University of Missouri (MU) team worked with GAMMA Remote Sensing to develop a specialized (dual-frequency, polarimetric, and interferometric) ground-based real-aperture RADAR (GBIR) instrument. The GBIR device is portable with its tripod system and control electronics. It can be deployed to obtain data with high spatial resolution (i.e. on the order of 1 meter) and high temporal resolution (i.e. on the order 1 minute). The high temporal resolution is well suited for measurements of rapid deformation. From the same geodetic position, the GBIR may collect dual frequency data set using C-band and Ku-band. The overall goal of this project is to measure the deformation from various scenarios by applying the GBIR system. Initial efforts have been focusing on testing the system performance on different types of targets. This thesis details a number of my efforts on experimental and processing activities at the start of the MU GBIR imaging project. For improved close range capability, a wideband dual polarized antenna option was produced and tested. For GBIR calibration, several trihedral corner reflectors were designed and fabricated. In addition to experimental activities and site selection, I participated in advanced data processing activities. I processed GBIR data in several ways including single-look-complex (SLC) image generation, imagery registration, and interferometric processing. A number of initial-processed GBIR image products are presented from four dams: Longview, Blue Springs, Tuttle Creek, and Milford. Excellent imaging performance of the MU GBIR has been observed for various target types such as riprap, concrete, soil, rock, metal, and vegetation. Strong coherence of the test scene has been observed in the initial interferograms.

The 2016 interferometric imaging beauty contest

Science.gov (United States)

Sanchez-Bermudez, J.; Thiébaut, E.; Hofmann, K.-H.; Heininger, M.; Schertl, D.; Weigelt, G.; Millour, F.; Schutz, A.; Ferrari, A.; Vannier, M.; Mary, D.; Young, J.

2016-08-01

Image reconstruction in optical interferometry has gained considerable importance for astrophysical studies during the last decade. This has been mainly due to improvements in the imaging capabilities of existing interferometers and the expectation of new facilities in the coming years. However, despite the advances made so far, image synthesis in optical interferometry is still an open field of research. Since 2004, the community has organized a biennial contest to formally test the different methods and algorithms for image reconstruction. In 2016, we celebrated the 7th edition of the "Interferometric Imaging Beauty Contest". This initiative represented an open call to participate in the reconstruction of a selected set of simulated targets with a wavelength-dependent morphology as they could be observed by the 2nd generation of VLTI instruments. This contest represents a unique opportunity to benchmark, in a systematic way, the current advances and limitations in the field, as well as to discuss possible future approaches. In this contribution, we summarize: (a) the rules of the 2016 contest; (b) the different data sets used and the selection procedure; (c) the methods and results obtained by each one of the participants; and (d) the metric used to select the best reconstructed images. Finally, we named Karl-Heinz Hofmann and the group of the Max-Planck-Institut fur Radioastronomie as winners of this edition of the contest.

A novel lightweight Fizeau infrared interferometric imaging system

Science.gov (United States)

Hope, Douglas A.; Hart, Michael; Warner, Steve; Durney, Oli; Romeo, Robert

2016-05-01

Aperture synthesis imaging techniques using an interferometer provide a means to achieve imagery with spatial resolution equivalent to a conventional filled aperture telescope at a significantly reduced size, weight and cost, an important implication for air- and space-borne persistent observing platforms. These concepts have been realized in SIRII (Space-based IR-imaging interferometer), a new light-weight, compact SWIR and MWIR imaging interferometer designed for space-based surveillance. The sensor design is configured as a six-element Fizeau interferometer; it is scalable, light-weight, and uses structural components and main optics made of carbon fiber replicated polymer (CFRP) that are easy to fabricate and inexpensive. A three-element prototype of the SIRII imager has been constructed. The optics, detectors, and interferometric signal processing principles draw on experience developed in ground-based astronomical applications designed to yield the highest sensitivity and resolution with cost-effective optical solutions. SIRII is being designed for technical intelligence from geo-stationary orbit. It has an instantaneous 6 x 6 mrad FOV and the ability to rapidly scan a 6x6 deg FOV, with a minimal SNR. The interferometric design can be scaled to larger equivalent filled aperture, while minimizing weight and costs when compared to a filled aperture telescope with equivalent resolution. This scalability in SIRII allows it address a range of IR-imaging scenarios.

Gravitational states of antihydrogen near material surface

Energy Technology Data Exchange (ETDEWEB)

Voronin, Alexei Yu., E-mail: dr.a.voronin@gmail.com [P.N. Lebedev Physical Institute (Russian Federation); Froelich, Piotr [Uppsala University, Department of Quantum Chemistry (Sweden); Nesvizhevsky, Valery V. [Institut Laue-Langevin (ILL) (France)

2012-12-15

We present a theoretical study of the motion of antihydrogen atoms in the Earth's gravitational field near a material surface. We predict the existence of long-living quasistationary states of antihydrogen in a superposition of the gravitational and Casimir-van der Waals potentials of the surface. We suggest an interferometric method of measuring the energy difference between such gravitational states, hence the gravitational mass of antihydrogen.

Contrast computation methods for interferometric measurement of sensor modulation transfer function

Science.gov (United States)

Battula, Tharun; Georgiev, Todor; Gille, Jennifer; Goma, Sergio

2018-01-01

Accurate measurement of image-sensor frequency response over a wide range of spatial frequencies is very important for analyzing pixel array characteristics, such as modulation transfer function (MTF), crosstalk, and active pixel shape. Such analysis is especially significant in computational photography for the purposes of deconvolution, multi-image superresolution, and improved light-field capture. We use a lensless interferometric setup that produces high-quality fringes for measuring MTF over a wide range of frequencies (here, 37 to 434 line pairs per mm). We discuss the theoretical framework, involving Michelson and Fourier contrast measurement of the MTF, addressing phase alignment problems using a moiré pattern. We solidify the definition of Fourier contrast mathematically and compare it to Michelson contrast. Our interferometric measurement method shows high detail in the MTF, especially at high frequencies (above Nyquist frequency). We are able to estimate active pixel size and pixel pitch from measurements. We compare both simulation and experimental MTF results to a lens-free slanted-edge implementation using commercial software.

New orbital elements of 5 interferometric double stars

Directory of Open Access Journals (Sweden)

Olević D.

1999-01-01

Full Text Available In this paper, for the first time, are presented elliptical and Thiel- Innes orbitatal elements for the following interferometric pairs: WDS 00416+2438 = WRH, WDS 03271+1845 = CHARA 10, WDS 04044+2406 = McA 13 Aa, WDS 17095+4047 = McA 45 and WDS 23019+4219 = o And Aa. For the pairs WDS 03271+1845 = CHARA 10 andWDS 04044+2406 = McA 13 Aa are calculated total masses and dynamical parallaxes which are compared with corresponding Hipparcos parallaxes.

Digital elevation model generation from satellite interferometric synthetic aperture radar: Chapter 5

Science.gov (United States)

Lu, Zhong; Dzurisin, Daniel; Jung, Hyung-Sup; Zhang, Lei; Lee, Wonjin; Lee, Chang-Wook

2012-01-01

An accurate digital elevation model (DEM) is a critical data set for characterizing the natural landscape, monitoring natural hazards, and georeferencing satellite imagery. The ideal interferometric synthetic aperture radar (InSAR) configuration for DEM production is a single-pass two-antenna system. Repeat-pass single-antenna satellite InSAR imagery, however, also can be used to produce useful DEMs. DEM generation from InSAR is advantageous in remote areas where the photogrammetric approach to DEM generation is hindered by inclement weather conditions. There are many sources of errors in DEM generation from repeat-pass InSAR imagery, for example, inaccurate determination of the InSAR baseline, atmospheric delay anomalies, and possible surface deformation because of tectonic, volcanic, or other sources during the time interval spanned by the images. This chapter presents practical solutions to identify and remove various artifacts in repeat-pass satellite InSAR images to generate a high-quality DEM.

Matterwave interferometric velocimetry of cold Rb atoms

Science.gov (United States)

Carey, Max; Belal, Mohammad; Himsworth, Matthew; Bateman, James; Freegarde, Tim

2018-03-01

We consider the matterwave interferometric measurement of atomic velocities, which forms a building block for all matterwave inertial measurements. A theoretical analysis, addressing both the laboratory and atomic frames and accounting for residual Doppler sensitivity in the beamsplitter and recombiner pulses, is followed by an experimental demonstration, with measurements of the velocity distribution within a 20 ?K cloud of rubidium atoms. Our experiments use Raman transitions between the long-lived ground hyperfine states, and allow quadrature measurements that yield the full complex interferometer signal and hence discriminate between positive and negative velocities. The technique is most suitable for measurement of colder samples.

Coherent laser radar with dual-frequency Doppler estimation and interferometric range detection

NARCIS (Netherlands)

Onori, D.; Scotti, F.; Laghezza, F.; Scaffardi, M.; Bogoni, A.

2016-01-01

The concept of a coherent interferometric dual frequency laser radar, that measures both the target range and velocity, is presented and experimentally demonstrated. The innovative architecture combines the dual frequency lidar concept, allowing a precise and robust Doppler estimation, with the

A neural network-based approach to noise identification of interferometric GW antennas: the case of the 40 m Caltech laser interferometer

Energy Technology Data Exchange (ETDEWEB)

Acernese, F [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Barone, F [Istituto Nazionale di Fisica Nucleare, sez. Napoli, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Rosa, M de [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Rosa, R De [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Eleuteri, A [Istituto Nazionale di Fisica Nucleare, sez. Napoli, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Milano, L [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Tagliaferri, R [Dipartimento di Matematica ed Informatica, Universita di Salerno, via S Allende, I-84081 Baronissi (Salerno) (Italy)

2002-06-21

In this paper, a neural network-based approach is presented for the real time noise identification of a GW laser interferometric antenna. The 40 m Caltech laser interferometer output data provide a realistic test bed for noise identification algorithms because of the presence of many relevant effects: violin resonances in the suspensions, main power harmonics, ring-down noise from servo control systems, electronic noises, glitches and so on. These effects can be assumed to be present in all the first interferometric long baseline GW antennas such as VIRGO, LIGO, GEO and TAMA. For noise identification, we used the Caltech-40 m laser interferometer data. The results we obtained are pretty good notwithstanding the high initial computational cost. The algorithm we propose is general and robust, taking into account that it does not require a priori information on the data, nor a precise model, and it constitutes a powerful tool for time series data analysis.

A neural network-based approach to noise identification of interferometric GW antennas: the case of the 40 m Caltech laser interferometer

International Nuclear Information System (INIS)

Acernese, F; Barone, F; Rosa, M de; Rosa, R De; Eleuteri, A; Milano, L; Tagliaferri, R

2002-01-01

In this paper, a neural network-based approach is presented for the real time noise identification of a GW laser interferometric antenna. The 40 m Caltech laser interferometer output data provide a realistic test bed for noise identification algorithms because of the presence of many relevant effects: violin resonances in the suspensions, main power harmonics, ring-down noise from servo control systems, electronic noises, glitches and so on. These effects can be assumed to be present in all the first interferometric long baseline GW antennas such as VIRGO, LIGO, GEO and TAMA. For noise identification, we used the Caltech-40 m laser interferometer data. The results we obtained are pretty good notwithstanding the high initial computational cost. The algorithm we propose is general and robust, taking into account that it does not require a priori information on the data, nor a precise model, and it constitutes a powerful tool for time series data analysis

A neural network-based approach to noise identification of interferometric GW antennas: the case of the 40 m Caltech laser interferometer

CERN Document Server

Acernese, F; Rosa, M D; Rosa, R D; Eleuteri, A; Milano, L; Tagliaferri, R

2002-01-01

In this paper, a neural network-based approach is presented for the real time noise identification of a GW laser interferometric antenna. The 40 m Caltech laser interferometer output data provide a realistic test bed for noise identification algorithms because of the presence of many relevant effects: violin resonances in the suspensions, main power harmonics, ring-down noise from servo control systems, electronic noises, glitches and so on. These effects can be assumed to be present in all the first interferometric long baseline GW antennas such as VIRGO, LIGO, GEO and TAMA. For noise identification, we used the Caltech-40 m laser interferometer data. The results we obtained are pretty good notwithstanding the high initial computational cost. The algorithm we propose is general and robust, taking into account that it does not require a priori information on the data, nor a precise model, and it constitutes a powerful tool for time series data analysis.

The second order extended Kalman filter and Markov nonlinear filter for data processing in interferometric systems

International Nuclear Information System (INIS)

Ermolaev, P; Volynsky, M

2014-01-01

Recurrent stochastic data processing algorithms using representation of interferometric signal as output of a dynamic system, which state is described by vector of parameters, in some cases are more effective, compared with conventional algorithms. Interferometric signals depend on phase nonlinearly. Consequently it is expedient to apply algorithms of nonlinear stochastic filtering, such as Kalman type filters. An application of the second order extended Kalman filter and Markov nonlinear filter that allows to minimize estimation error is described. Experimental results of signals processing are illustrated. Comparison of the algorithms is presented and discussed.

Jet-Surface Interaction - High Aspect Ratio Nozzle Test: Test Summary

Science.gov (United States)

Brown, Clifford A.

2016-01-01

The Jet-Surface Interaction High Aspect Ratio Nozzle Test was conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center in the fall of 2015. There were four primary goals specified for this test: (1) extend the current noise database for rectangular nozzles to higher aspect ratios, (2) verify data previously acquired at small-scale with data from a larger model, (3) acquired jet-surface interaction noise data suitable for creating verifying empirical noise models and (4) investigate the effect of nozzle septa on the jet-mixing and jet-surface interaction noise. These slides give a summary of the test with representative results for each goal.

Characterisation of a cryostat using simultaneous, single-beam multiple-surface laser vibrometry

Energy Technology Data Exchange (ETDEWEB)

Kissinger, Thomas; Charrett, Thomas O. H.; James, Stephen W.; Tatam, Ralph P., E-mail: r.p.tatam@cranfield.ac.uk [Engineering Photonics, Cranfield University, Cranfield, MK43 0AL (United Kingdom); Adams, Alvin; Twin, Andrew [Oxford Instruments Nanoscience, Tubney Woods, Abingdon, Oxon, OX13 5QX (United Kingdom)

2016-06-28

A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm · Hz{sup −05}. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder target inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the target, allowing any resonances to be identified.

Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors

International Nuclear Information System (INIS)

Yamamoto, Kazuhiro; Hayakawa, Hideaki; Okada, Atsushi; Uchiyama, Takashi; Miyoki, Shinji; Ohashi, Masatake; Kuroda, Kazuaki; Kanda, Nobuyuki; Tatsumi, Daisuke; Tsunesada, Yoshiki

2008-01-01

We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100 times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

Laser amplitude stabilization for advanced interferometric gravitational wave detectors

International Nuclear Information System (INIS)

Barr, B W; Strain, K A; Killow, C J

2005-01-01

We present results of experiments into the stabilization of the amplitude of Nd:YAG lasers for use in advanced gravitational wave detectors. By feeding back directly to the pump-diode driving current we achieved shot-noise-limited stabilization at frequencies up to several kHz with some residual noise at lower frequencies (sub ∼100 Hz). The method used is applicable to higher powered laser systems planned for advanced interferometric gravitational wave detectors

AN ASSESSMENT OF SPACEBORNE NEAR-NADIR INTERFEROMETRIC SAR PERFORMANCE OVER INLAND WATERS WITH REAL

Directory of Open Access Journals (Sweden)

H. Tan

2018-04-01

Full Text Available Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA, which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

An Assessment of Spaceborne Near-Nadir Interferometric SAR Performance Over Inland Waters with Real

Science.gov (United States)

Tan, H.; Li, S. Y.; Liu, Z. W.

2018-04-01

Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA), which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

KAUST Repository

Katterbauer, Klemens

2016-08-25

Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels and estimating critical reservoir parameters, the sparse spatial nature of this dataset limits the efficiency of the history matching process. Recently, gravimetry techniques have significantly advanced to the point of providing measurement accuracy in the microgal range and consequently can be used for the tracking of gas displacement caused by water influx. While gravity measurements provide information on subsurface density changes, i.e., the composition of the reservoir, these data do only yield marginal information about temporal displacements of oil and inflowing water. We propose to complement gravimetric data with interferometric synthetic aperture radar surface deformation data to exploit the strong pressure deformation relationship for enhancing fluid flow direction forecasts. We have developed an ensemble Kalman-filter-based history matching framework for gas, gas condensate, and volatile oil reservoirs, which synergizes time-lapse gravity and interferometric synthetic aperture radar data for improved reservoir management and reservoir forecasts. Based on a dual state-parameter estimation algorithm separating the estimation of static reservoir parameters from the dynamic reservoir parameters, our numerical experiments demonstrate that history matching gravity measurements allow monitoring the density changes caused by oil-gas phase transition and water influx to determine the saturation levels, whereas the interferometric synthetic aperture radar measurements help to improve the forecasts of hydrocarbon production and water displacement directions. The reservoir estimates resulting from the dual filtering scheme are on average 20%-40% better than those from the joint estimation scheme, but require about a 30% increase in

Surface plasmon polariton propagation in organic nanofiber based plasmonic waveguides

DEFF Research Database (Denmark)

Leißner, Till; Lemke, Christoph; Jauernik, Stephan

2013-01-01

Plasmonic wave packet propagation is monitored in dielectric-loaded surface plasmon polariton waveguides realized from para-hexaphenylene nanofibers deposited onto a 60 nm thick gold film. Using interferometric time resolved two-photon photoemission electron microscopy we are able to determine...

BAYESIAN SEMI-BLIND COMPONENT SEPARATION FOR FOREGROUND REMOVAL IN INTERFEROMETRIC 21 cm OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Zhang, Le; Timbie, Peter T. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Bunn, Emory F. [Physics Department, University of Richmond, Richmond, VA 23173 (United States); Karakci, Ata; Korotkov, Andrei; Tucker, Gregory S. [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States); Sutter, P. M. [Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Wandelt, Benjamin D., E-mail: lzhang263@wisc.edu [Department of Physics, University of Illinois at Urbana-Champaign, 1110 W Green Street, Urbana, IL 61801 (United States)

2016-01-15

In this paper, we present a new Bayesian semi-blind approach for foreground removal in observations of the 21 cm signal measured by interferometers. The technique, which we call H i Expectation–Maximization Independent Component Analysis (HIEMICA), is an extension of the Independent Component Analysis technique developed for two-dimensional (2D) cosmic microwave background maps to three-dimensional (3D) 21 cm cosmological signals measured by interferometers. This technique provides a fully Bayesian inference of power spectra and maps and separates the foregrounds from the signal based on the diversity of their power spectra. Relying only on the statistical independence of the components, this approach can jointly estimate the 3D power spectrum of the 21 cm signal, as well as the 2D angular power spectrum and the frequency dependence of each foreground component, without any prior assumptions about the foregrounds. This approach has been tested extensively by applying it to mock data from interferometric 21 cm intensity mapping observations under idealized assumptions of instrumental effects. We also discuss the impact when the noise properties are not known completely. As a first step toward solving the 21 cm power spectrum analysis problem, we compare the semi-blind HIEMICA technique to the commonly used Principal Component Analysis. Under the same idealized circumstances, the proposed technique provides significantly improved recovery of the power spectrum. This technique can be applied in a straightforward manner to all 21 cm interferometric observations, including epoch of reionization measurements, and can be extended to single-dish observations as well.

Visibility-based angular power spectrum estimation in low-frequency radio interferometric observations

NARCIS (Netherlands)

Choudhuri, Samir; Bharadwaj, Somnath; Ghosh, Abhik; Ali, Sk. Saiyad

2014-01-01

We present two estimators to quantify the angular power spectrum of the sky signal directly from the visibilities measured in radio interferometric observations. This is relevant for both the foregrounds and the cosmological 21-cm signal buried therein. The discussion here is restricted to the

Interferometric control of the photon-number distribution

Directory of Open Access Journals (Sweden)

H. Esat Kondakci

2017-07-01

Full Text Available We demonstrate deterministic control over the photon-number distribution by interfering two coherent beams within a disordered photonic lattice. By sweeping a relative phase between two equal-amplitude coherent fields with Poissonian statistics that excite adjacent sites in a lattice endowed with disorder-immune chiral symmetry, we measure an output photon-number distribution that changes periodically between super-thermal and sub-thermal photon statistics upon ensemble averaging. Thus, the photon-bunching level is controlled interferometrically at a fixed mean photon-number by gradually activating the excitation symmetry of the chiral-mode pairs with structured coherent illumination and without modifying the disorder level of the random system itself.

Ultra-Low Noise Quad Photoreceiver for Space Based Laser Interferometric Gravity Wave Detection, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Gravity wave detection using space-based long-baseline laser interferometric sensors imposes stringent noise requirements on the system components, including the...

Imaging Stars by Performing Full-Stokes Optical Interferometric Polarimetry

Directory of Open Access Journals (Sweden)

Nicholas M. Elias II

2012-03-01

Full Text Available Optical interferometry and polarimetry have separately provided new insights into stellar astronomy, especially in the fields of fundamental parameters and atmospheric models. We present: scientific justifications for “full-Stokes” optical interferometric polarimetry (OIP; updated instrument requirements; preliminary beam combiner designs; polarimeter design; end-to-end OIP data reduction; and realistic reimaged full-Stokes models of Be stars with a suitable number of telescopes plus noise sources. All of this work represents preliminary research to construct an OIP beam combiner.

Seismic time-lapse imaging using Interferometric least-squares migration

KAUST Repository

Sinha, Mrinal

2016-09-06

One of the problems with 4D surveys is that the environmental conditions change over time so that the experiment is insufficiently repeatable. To mitigate this problem, we propose the use of interferometric least-squares migration (ILSM) to estimate the migration image for the baseline and monitor surveys. Here, a known reflector is used as the reference reflector for ILSM. Results with synthetic and field data show that ILSM can eliminate artifacts caused by non-repeatability in time-lapse surveys.

Seismic time-lapse imaging using Interferometric least-squares migration

KAUST Repository

Sinha, Mrinal; Schuster, Gerard T.

2016-01-01

One of the problems with 4D surveys is that the environmental conditions change over time so that the experiment is insufficiently repeatable. To mitigate this problem, we propose the use of interferometric least-squares migration (ILSM) to estimate the migration image for the baseline and monitor surveys. Here, a known reflector is used as the reference reflector for ILSM. Results with synthetic and field data show that ILSM can eliminate artifacts caused by non-repeatability in time-lapse surveys.

Dynamic measurements of flowing cells labeled by gold nanoparticles using full-field photothermal interferometric imaging

Science.gov (United States)

Turko, Nir A.; Roitshtain, Darina; Blum, Omry; Kemper, Björn; Shaked, Natan T.

2017-06-01

We present highly dynamic photothermal interferometric phase microscopy for quantitative, selective contrast imaging of live cells during flow. Gold nanoparticles can be biofunctionalized to bind to specific cells, and stimulated for local temperature increase due to plasmon resonance, causing a rapid change of the optical phase. These phase changes can be recorded by interferometric phase microscopy and analyzed to form an image of the binding sites of the nanoparticles in the cells, gaining molecular specificity. Since the nanoparticle excitation frequency might overlap with the sample dynamics frequencies, photothermal phase imaging was performed on stationary or slowly dynamic samples. Furthermore, the computational analysis of the photothermal signals is time consuming. This makes photothermal imaging unsuitable for applications requiring dynamic imaging or real-time analysis, such as analyzing and sorting cells during fast flow. To overcome these drawbacks, we utilized an external interferometric module and developed new algorithms, based on discrete Fourier transform variants, enabling fast analysis of photothermal signals in highly dynamic live cells. Due to the self-interference module, the cells are imaged with and without excitation in video-rate, effectively increasing signal-to-noise ratio. Our approach holds potential for using photothermal cell imaging and depletion in flow cytometry.

Simultaneous time-space resolved reflectivity and interferometric measurements of dielectrics excited with femtosecond laser pulses

Science.gov (United States)

Garcia-Lechuga, M.; Haahr-Lillevang, L.; Siegel, J.; Balling, P.; Guizard, S.; Solis, J.

2017-06-01

Simultaneous time-and-space resolved reflectivity and interferometric measurements over a temporal span of 300 ps have been performed in fused silica and sapphire samples excited with 800 nm, 120 fs laser pulses at energies slightly and well above the ablation threshold. The experimental results have been simulated in the frame of a multiple-rate equation model including light propagation. The comparison of the temporal evolution of the reflectivity and the interferometric measurements at 400 nm clearly shows that the two techniques interrogate different material volumes during the course of the process. While the former is sensitive to the evolution of the plasma density in a very thin ablating layer at the surface, the second yields an averaged plasma density over a larger volume. It is shown that self-trapped excitons do not appreciably contribute to carrier relaxation in fused silica at fluences above the ablation threshold, most likely due to Coulomb screening effects at large excited carrier densities. For both materials, at fluences well above the ablation threshold, the maximum measured plasma reflectivity shows a saturation behavior consistent with a scattering rate proportional to the plasma density in this fluence regime. Moreover, for both materials and for pulse energies above the ablation threshold and delays in the few tens of picoseconds range, a simultaneous "low reflectivity" and "low transmission" behavior is observed. Although this behavior has been identified in the past as a signature of femtosecond laser-induced ablation, its origin is alternatively discussed in terms of the optical properties of a material undergoing strong isochoric heating, before having time to substantially expand or exchange energy with the surrounding media.

Application of identifying transmission spheres for spherical surface testing

Science.gov (United States)

Han, Christopher B.; Ye, Xin; Li, Xueyuan; Wang, Quanzhao; Tang, Shouhong; Han, Sen

2017-06-01

We developed a new application on Microsoft Foundation Classes (MFC) to identify correct transmission spheres (TS) for Spherical Surface Testing (SST). Spherical surfaces are important optical surfaces, and the wide application and high production rate of spherical surfaces necessitates an accurate and highly reliable measuring device. A Fizeau Interferometer is an appropriate tool for SST due to its subnanometer accuracy. It measures the contour of a spherical surface using a common path, which is insensitive to the surrounding circumstances. The Fizeau Interferometer transmits a wide laser beam, creating interference fringes from re-converging light from the transmission sphere and the test surface. To make a successful measurement, the application calculates and determines the appropriate transmission sphere for the test surface. There are 3 main inputs from the test surfaces that are utilized to determine the optimal sizes and F-numbers of the transmission spheres: (1) the curvatures (concave or convex), (2) the Radii of Curvature (ROC), and (3) the aperture sizes. The application will firstly calculate the F-numbers (i.e. ROC divided by aperture) of the test surface, secondly determine the correct aperture size of a convex surface, thirdly verify that the ROC of the test surface must be shorter than the reference surface's ROC of the transmission sphere, and lastly calculate the percentage of area that the test surface will be measured. However, the amount of interferometers and transmission spheres should be optimized when measuring large spherical surfaces to avoid requiring a large amount of interferometers and transmission spheres for each test surface. Current measuring practices involve tedious and potentially inaccurate calculations. This smart application eliminates human calculation errors, optimizes the selection of transmission spheres (including the least number required) and interferometer sizes, and increases efficiency.

Non-Interferometric Tomography of Phase Objects Using Spatial Light Modulators

Directory of Open Access Journals (Sweden)

Thanh Nguyen

2016-10-01

Full Text Available Quantitative 3D phase retrieval techniques are based on either interferometric techniques such as holography or noninterferometric intensity-based techniques such as the transport of intensity equation (TIE. Interferometric techniques are vibration-sensitive and often use a reference beam requiring complicated optical alignment. In this work we develop a simple, fast, and noninterferometric tomographic 3D phase retrieval technique based on the TIE which does not suffer from such drawbacks. The optical setup is a modified 4f TIE system which uses an SLM to replace the slow translation of the CCD required to record several diffraction patterns in a traditional TIE system. This novel TIE setup is suitable for dynamical events such as imaging biological processes. A rotating mechanical stage is constructed to obtain tomographic phase images of the object. The tomographic reconstruction algorithm is based on the Fourier slice theorem (backprojection algorithm which applies to objects with a small refractive index span. Simulation and experimental results are shown as part of this work. A graphical user interface is developed to perform the TIE tomographic reconstruction algorithm and to synchronize the captured intensities by the CCD, the phase patterns displayed on the SLM, and the Arduino controlled rotating stage assembly.

Interferometric laser imaging for in-flight cloud droplet sizing

International Nuclear Information System (INIS)

Dunker, Christina; Roloff, Christoph; Grassmann, Arne

2016-01-01

A non-intrusive particle sizing method with a high spatial distribution is used to estimate cloud droplet spectra during flight test campaigns. The interferometric laser imaging for droplet sizing (ILIDS) method derives particle diameters of transparent spheres by evaluating the out-of-focus image patterns. This sizing approach requires a polarized monochromatic light source, a camera including an objective lens with a slit aperture, a synchronization unit and a processing tool for data evaluation. These components are adapted to a flight test environment to enable the microphysical investigation of different cloud genera. The present work addresses the design and specifications of ILIDS system, flight test preparation and selected results obtained in the lower and middle troposphere. The research platform was a Dornier Do228-101 commuter aircraft at the DLR Flight Operation Center in Braunschweig. It was equipped with the required instrumentation including a high-energy laser as the light source. A comprehensive data set of around 71 800 ILIDS images was acquired over the course of five flights. The data evaluation of the characteristic ILIDS fringe patterns relies, among other things, on a relationship between the fringe spacing and the diameter of the particle. The simplest way to extract this information from a pattern is by fringe counting, which is not viable for such an extensive number of data. A brief contrasting comparison of evaluation methods based on frequency analysis by means of fast Fourier transform and on correlation methods such as minimum quadratic difference is used to encompass the limits and accuracy of the ILIDS method for such applications. (paper)

Accuracy of three-dimensional glacier surface volocities derived from radar interfeometry and ice-soundin radar measurements

DEFF Research Database (Denmark)

Mohr, Johan Jacob; Reeh, Niels; Madsen, Søren Nørvang

2003-01-01

We present a method for analyzing the errors involved in measuring three-dimensional glacier velocities with interferometric radar. We address the surface-parallel flow assumption and an augmented approach with a flux-divergence (FD) term. The errors in an interferometric ERS-1/-2 satellite radar...... dataset with ascending- and descending-orbit data covering Storstrommen glacier, northeast Greenland, are assessed. The FD error assessment is carried out on airborne 60 MHz ice-sounding radar data from the same area. A simple model of an interferometric radar system is developed and analyzed. The error...... sources considered include phase noise, atmospheric distortions, baseline calibration errors, a dry snow layer, and the stationary-flow assumption used in differential interferometry. The additional error sources in the analysis of FD errors are noise, bias and unknown variations of the ice thickness...

A method of noise reduction in heterodyne interferometric vibration metrology by combining auto-correlation analysis and spectral filtering

Science.gov (United States)

Hao, Hongliang; Xiao, Wen; Chen, Zonghui; Ma, Lan; Pan, Feng

2018-01-01

Heterodyne interferometric vibration metrology is a useful technique for dynamic displacement and velocity measurement as it can provide a synchronous full-field output signal. With the advent of cost effective, high-speed real-time signal processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. However, due to the coherent nature of the laser sources, the sequence of heterodyne interferogram are corrupted by a mixture of coherent speckle and incoherent additive noise, which can severely degrade the accuracy of the demodulated signal and the optical display. In this paper, a new heterodyne interferometric demodulation method by combining auto-correlation analysis and spectral filtering is described leading to an expression for the dynamic displacement and velocity of the object under test that is significantly more accurate in both the amplitude and frequency of the vibrating waveform. We present a mathematical model of the signals obtained from interferograms that contain both vibration information of the measured objects and the noise. A simulation of the signal demodulation process is presented and used to investigate the noise from the system and external factors. The experimental results show excellent agreement with measurements from a commercial Laser Doppler Velocimetry (LDV).

Detection and description of surface breaking cracks by means of optical sound field visualization

International Nuclear Information System (INIS)

Crostack, H.A.; Krueger, A.

1986-01-01

The authors present an ultrasound testing method for surface-breaking cracks in components. The method is based on large-area imaging of ultrasound by means of an optical receiver system. The receiver system is based on the principle of holographic interferometry. Application of double exposure technique using a double pulse laser and of sensitivity boosting measures allowed to construct a holographic sound field camera (sensitivity threshold: 0.2 nm) which allows large-area sound detection (in the square meter range) without requiring the usual methods for vibrational insulation in contrast to all the other optical interferometric and holographic techniques. (orig./DG) [de

Reduction of interferometric crosstalk induced penalty using a saturated semiconductor optical amplifier

DEFF Research Database (Denmark)

Liu, Fenghai; Zheng, Xueyan; Poulsen, Henrik Nørskov

2000-01-01

We successfully demonstrated that a simple saturated SOA could be used to reduce the impact from the interferometric crosstalk at 2.5 and 10 Gb/s. It is shown that 4 dB more crosstalk power can be tolerated at 1 dB penalty by using the SOA. This will greatly reduce the crosstalk requirement...

A new interferometric study of four exoplanet host stars: θ Cygni, 14 Andromedae, υ Andromedae and 42 Draconis

Science.gov (United States)

Ligi, R.; Mourard, D.; Lagrange, A. M.; Perraut, K.; Boyajian, T.; Bério, Ph.; Nardetto, N.; Tallon-Bosc, I.; McAlister, H.; ten Brummelaar, T.; Ridgway, S.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

2012-09-01

Context. Since the discovery of the first exoplanet in 1995 around a solar-type star, the interest in exoplanetary systems has kept increasing. Studying exoplanet host stars is of the utmost importance to establish the link between the presence of exoplanets around various types of stars and to understand the respective evolution of stars and exoplanets. Aims: Using the limb-darkened diameter (LDD) obtained from interferometric data, we determine the fundamental parameters of four exoplanet host stars. We are particularly interested in the F4 main-sequence star, θ Cyg, for which Kepler has recently revealed solar-like oscillations that are unexpected for this type of star. Furthermore, recent photometric and spectroscopic measurements with SOPHIE and ELODIE (OHP) show evidence of a quasi-periodic radial velocity of ~150 days. Models of this periodic change in radial velocity predict either a complex planetary system orbiting the star, or a new and unidentified stellar pulsation mode. Methods: We performed interferometric observations of θ Cyg, 14 Andromedae, υ Andromedae and 42 Draconis for two years with VEGA/CHARA (Mount Wilson, California) in several three-telescope configurations. We measured accurate limb darkened diameters and derived their radius, mass and temperature using empirical laws. Results: We obtain new accurate fundamental parameters for stars 14 And, υ And and 42 Dra. We also obtained limb darkened diameters with a minimum precision of ~1.3%, leading to minimum planet masses of Msini = 5.33 ± 0.57, 0.62 ± 0.09 and 3.79 ± 0.29 MJup for 14 And b, υ And b and 42 Dra b, respectively. The interferometric measurements of θ Cyg show a significant diameter variability that remains unexplained up to now. We propose that the presence of these discrepancies in the interferometric data is caused either by an intrinsic variation of the star or an unknown close companion orbiting around it. Based on interferometric observations with the VEGA

Interferometric microstructured polymer optical fiber ultrasound sensor for optoacoustic endoscopic imaging in biomedical applications

DEFF Research Database (Denmark)

Gallego, Daniel; Sáez-Rodríguez, David; Webb, David

2014-01-01

to conventional piezoelectric transducers. These kind of sensors, made of biocompatible polymers, are good candidates for the sensing element in an optoacoustic endoscope because of its high sensitivity, its shape and its non-brittle and non-electric nature. The acoustic sensitivity of the intrinsic fiber optic......We report a characterization of the acoustic sensitivity of microstructured polymer optical fiber interferometric sensors at ultrasonic frequencies from 100kHz to 10MHz. The use of wide-band ultrasonic fiber optic sensors in biomedical ultrasonic and optoacoustic applications is an open alternative...... interferometric sensors depends strongly of the material which is composed of. In this work we compare experimentally the intrinsic ultrasonic sensitivities of a PMMA mPOF with other three optical fibers: a singlemode silica optical fiber, a single-mode polymer optical fiber and a multimode graded...

Improving waveform inversion using modified interferometric imaging condition

Science.gov (United States)

Guo, Xuebao; Liu, Hong; Shi, Ying; Wang, Weihong; Zhang, Zhen

2018-02-01

Similar to the reverse-time migration, full waveform inversion in the time domain is a memory-intensive processing method. The computational storage size for waveform inversion mainly depends on the model size and time recording length. In general, 3D and 4D data volumes need to be saved for 2D and 3D waveform inversion gradient calculations, respectively. Even the boundary region wavefield-saving strategy creates a huge storage demand. Using the last two slices of the wavefield to reconstruct wavefields at other moments through the random boundary, avoids the need to store a large number of wavefields; however, traditional random boundary method is less effective at low frequencies. In this study, we follow a new random boundary designed to regenerate random velocity anomalies in the boundary region for each shot of each iteration. The results obtained using the random boundary condition in less illuminated areas are more seriously affected by random scattering than other areas due to the lack of coverage. In this paper, we have replaced direct correlation for computing the waveform inversion gradient by modified interferometric imaging, which enhances the continuity of the imaging path and reduces noise interference. The new imaging condition is a weighted average of extended imaging gathers can be directly used in the gradient computation. In this process, we have not changed the objective function, and the role of the imaging condition is similar to regularization. The window size for the modified interferometric imaging condition-based waveform inversion plays an important role in this process. The numerical examples show that the proposed method significantly enhances waveform inversion performance.

Dynamic spectro-polarimeter based on a modified Michelson interferometric scheme.

Science.gov (United States)

Dembele, Vamara; Jin, Moonseob; Baek, Byung-Joon; Kim, Daesuk

2016-06-27

A simple dynamic spectro-polarimeter based on a modified Michelson interferometric scheme is described. The proposed system can extract a spectral Stokes vector of a transmissive anisotropic object. Detail theoretical background is derived and experiments are conducted to verify the feasibility of the proposed novel snapshot spectro-polarimeter. The proposed dynamic spectro-polarimeter enables us to extract highly accurate spectral Stokes vector of any transmissive anisotropic object with a frame rate of more than 20Hz.

Binary pseudo-random gratings and arrays for calibration of the modulation transfer function of surface profilometers: recent developments

Energy Technology Data Exchange (ETDEWEB)

Barber, Samuel K.; Soldate, Paul; Anderson, Erik H.; Cambie, Rossana; Marchesini, Stefano; McKinney, Wanye R.; Takacs, Peter Z.; Voronov, Dmitry L.; Yashchuk, Valeriy V.

2009-07-07

The major problem of measurement of a power spectral density (PSD) distribution of the surface heights with surface profilometers arises due to the unknown Modulation Transfer Function (MTF) of the instruments. The MTF tends to distort the PSD at higher spatial frequencies. It has been suggested [Proc. SPIE 7077-7, (2007), Opt. Eng. 47 (7), 073602-1-5 (2008)] that the instrumental MTF of a surface profiler can be precisely measured using standard test surfaces based on binary pseudo-random (BPR) patterns. In the cited work, a one dimensional (1D) realization of the suggested method based on use of BPR gratings has been demonstrated. Here, we present recent achievements made in fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. The 2D BPRAs were used as standard test surfaces for 2D MTF calibration of the MicromapTM-570 interferometric microscope with all available objectives. The effects of fabrication imperfections on the efficiency of calibration are also discussed.

Interferometric full-waveform inversion of time-lapse data

KAUST Repository

Sinha, Mrinal

2017-08-17

One of the key challenges associated with time-lapse surveys is ensuring the repeatability between the baseline and monitor surveys. Non-repeatability between the surveys is caused by varying environmental conditions over the course of different surveys. To overcome this challenge, we propose the use of interferometric full waveform inversion (IFWI) for inverting the velocity model from data recorded by baseline and monitor surveys. A known reflector is used as the reference reflector for IFWI, and the data are naturally redatumed to this reference reflector using natural reflections as the redatuming operator. This natural redatuming mitigates the artifacts introduced by the repeatability errors that originate above the reference reflector.

Fracture Testing with Surface Crack Specimens. [especially the residual tensile strength test

Science.gov (United States)

Orange, T. W.

1974-01-01

Recommendations are given for the design, preparation, and static fracture testing of surface crack specimens. The recommendations are preceded by background information including discussions of stress intensity factors, crack opening displacements, and fracture toughness values associated with surface crack specimens. Cyclic load and sustained load tests are discussed briefly.

Self-referenced interferometer for cylindrical surfaces

Czech Academy of Sciences Publication Activity Database

Šarbort, Martin; Řeřucha, Šimon; Holá, Miroslava; Buchta, Zdeněk; Lazar, Josef

2015-01-01

Roč. 54, č. 33 (2015), s. 9930-9938 ISSN 1559-128X R&D Projects: GA MŠk ED0017/01/01; GA ČR GA15-18430S; GA MŠk(CZ) LO1212; GA TA ČR TE01020233 Institutional support: RVO:68081731 Keywords : metrological instrumentation * interferometric imaging * interferometry * surface measurements * optical inspection Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.598, year: 2015

Modelling the passive microwave signature from land surfaces: a review of recent results and application to the SMOS & SMAP soil moisture retrieval algorithms

Science.gov (United States)

Two passive microwave missions are currently operating at L-band to monitor surface soil moisture (SM) over continental surfaces. The SMOS sensor, based on an innovative interferometric technology enabling multi-angular signatures of surfaces to be measured, was launched in November 2009....

LOFT fuel rod surface temperature measurement testing

International Nuclear Information System (INIS)

Eaton, A.M.; Tolman, E.L.; Solbrig, C.W.

1978-01-01

Testing of the LOFT fuel rod cladding surface thermocouples has been performed to evaluate how accurately the LOFT thermocouples measure the cladding surface temperature during a loss-of-coolant accident (LOCA) sequence and what effect, if any, the thermocouple would have on core performance. Extensive testing has been done to characterize the thermocouple design. Thermal cycling and corrosion testing of the thermocouple weld design have provided an expected lifetime of 6000 hours when exposed to reactor coolant conditions of 620 K and 15.9 MPa and to sixteen thermal cycles with an initial temperature of 480 K and peak temperatures ranging from 870 to 1200K. Departure from nucleate boiling (DNB) tests have indicated a DNB penalty (5 to 28% lower) during steady state operation and negligible effects during LOCA blowdown caused by the LOFT fuel rod surface thermocouple arrangement. Experience with the thermocouple design in Power Burst Facility (PBF) and LOFT nonnuclear blowdown testing has been quite satisfactory. Tests discussed here were conducted using both stainless steel and zircaloy-clad electrically heated rod in the LOFT Test Support Facility (LTSF) blowdown simulation loop

Surface crack testing - state of technique and trends in development

International Nuclear Information System (INIS)

1991-01-01

This Seminar contains 12 lectures on the following subjects: State of technique in magnetic powder testing (K. Goebbels); Recognisability of faults and probability of faults in surface crack testing (W. Morgner); Requirements for picture processing systems for proving and assessing crack indications (M. Stadthaus); Possibilities and limits of automatic crack recognition in magnetic powder testing (V. Deutsch); Development of equipment for eddy current testing (M. Junger); Signal processing - a way of improving the recognisability of faults in eddy current testing (R. Becker); Methods of testing steel products for surface faults and their practical limits of fault recognisability (D. Thiery); Surface crack testing in pipe manufacture (R. Pawelletz); Surface crack testing in powerstation construction (L. v. Bernus); Trends in automation in surface crack testing (G. Maier); Eddy current testing in engine construction (E. Dickhaut); Eddy current testing in aircraft repair (F. Schur). (orig.) [de

Geometrical error calibration in reflective surface testing based on reverse Hartmann test

Science.gov (United States)

Gong, Zhidong; Wang, Daodang; Xu, Ping; Wang, Chao; Liang, Rongguang; Kong, Ming; Zhao, Jun; Mo, Linhai; Mo, Shuhui

2017-08-01

In the fringe-illumination deflectometry based on reverse-Hartmann-test configuration, ray tracing of the modeled testing system is performed to reconstruct the test surface error. Careful calibration of system geometry is required to achieve high testing accuracy. To realize the high-precision surface testing with reverse Hartmann test, a computer-aided geometrical error calibration method is proposed. The aberrations corresponding to various geometrical errors are studied. With the aberration weights for various geometrical errors, the computer-aided optimization of system geometry with iterative ray tracing is carried out to calibration the geometrical error, and the accuracy in the order of subnanometer is achieved.

The Space Infrared Interferometric Telescope (SPIRIT)

Science.gov (United States)

Leisawitz, David T.

2014-01-01

The far-infrared astrophysics community is eager to follow up Spitzer and Herschel observations with sensitive, high-resolution imaging and spectroscopy, for such measurements are needed to understand merger-driven star formation and chemical enrichment in galaxies, star and planetary system formation, and the development and prevalence of water-bearing planets. The Space Infrared Interferometric Telescope (SPIRIT) is a wide field-of-view space-based spatio-spectral interferometer designed to operate in the 25 to 400 micron wavelength range. This talk will summarize the SPIRIT mission concept, with a focus on the science that motivates it and the technology that enables it. Without mentioning SPIRIT by name, the astrophysics community through the NASA Astrophysics Roadmap Committee recently recommended this mission as the first in a series of space-based interferometers. Data from a laboratory testbed interferometer will be used to illustrate how the spatio-spectral interferometry technique works.

Phase-shifting Real-time Holographic Microscopy applied in micro-structures surface analysis

International Nuclear Information System (INIS)

Brito, I V; Gesualdi, M R R; Muramatsu, M; Ricardo, J

2011-01-01

The microscopic real-time analysis of micro structured materials is of great importance in various domains of science and technology. For other hand, the holographic interferometry comprises a group of powerful optical methods for non-destructive testing in surface analysis. The holographic microscopy uses the holographic interferometric techniques to obtain quantitative intensity and phase information of the optical waves by microscopic systems. With the development of CCD cameras, computers (hardware and software), and new materials for holographic recording, these techniques can be used to replace the classical form of registration and became promising tools in surface analysis. In this work, we developed a prototype of Photorefractive and Digital Holographic Microscope for real-time analysis of micro-structured systems based on the phase-shifting real-time holographic interferometry techniques. Using this apparatus, we are made analysis of shapes and surfaces to obtain the phase maps and the 3D profiles of some samples.

The InSAeS4 Airborne X-Band Interferometric SAR System: A First Assessment on Its Imaging and Topographic Mapping Capabilities

Directory of Open Access Journals (Sweden)

Stefano Perna

2016-01-01

Full Text Available We present in this work a first assessment of the imaging and topographic mapping capabilities of the InSAeS4 system, which is a single-pass interferometric airborne X-Band Synthetic Aperture Radar (SAR. In particular, we first provide a brief description of the InSAeS4 sensor. Then, we discuss the results of our analysis on the SAR and interferometric SAR products relevant to the first flight-test campaign. More specifically, we have exploited as reference the GPS measurements relevant to nine Corner Reflectors (CRs deployed over the illuminated area during the campaign and a laser scanner Digital Elevation Model (DEM. From the analysis carried out on the CRs we achieved a mean geometric resolution, for the SAR products, of about 0.14 m in azimuth and 0.49 m in range, a positioning misalignment with standard deviation of 0.07 m in range and 0.08 m in azimuth, and a height error with standard deviation of 0.51 m. From the comparison with the laser scanner DEM we estimated a height error with standard deviation of 1.57 m.

Data quality studies of enhanced interferometric gravitational wave detectors

International Nuclear Information System (INIS)

McIver, Jessica

2012-01-01

Data quality assessment plays an essential role in the quest to detect gravitational wave signals in data from the LIGO and Virgo interferometric gravitational wave detectors. Interferometer data contain a high rate of noise transients from the environment, the detector hardware and the detector control systems. These transients severely limit the statistical significance of gravitational wave candidates of short duration and/or poorly modeled waveforms. This paper describes the data quality studies that have been performed in recent LIGO and Virgo observing runs to mitigate the impact of transient detector artifacts on the gravitational wave searches. (paper)

Reconstruction of source location in a network of gravitational wave interferometric detectors

International Nuclear Information System (INIS)

Cavalier, Fabien; Barsuglia, Matteo; Bizouard, Marie-Anne; Brisson, Violette; Clapson, Andre-Claude; Davier, Michel; Hello, Patrice; Kreckelbergh, Stephane; Leroy, Nicolas; Varvella, Monica

2006-01-01

This paper deals with the reconstruction of the direction of a gravitational wave source using the detection made by a network of interferometric detectors, mainly the LIGO and Virgo detectors. We suppose that an event has been seen in coincidence using a filter applied on the three detector data streams. Using the arrival time (and its associated error) of the gravitational signal in each detector, the direction of the source in the sky is computed using a χ 2 minimization technique. For reasonably large signals (SNR>4.5 in all detectors), the mean angular error between the real location and the reconstructed one is about 1 deg. . We also investigate the effect of the network geometry assuming the same angular response for all interferometric detectors. It appears that the reconstruction quality is not uniform over the sky and is degraded when the source approaches the plane defined by the three detectors. Adding at least one other detector to the LIGO-Virgo network reduces the blind regions and in the case of 6 detectors, a precision less than 1 deg. on the source direction can be reached for 99% of the sky

A frequency domain radar interferometric imaging (FII) technique based on high-resolution methods

Science.gov (United States)

Luce, H.; Yamamoto, M.; Fukao, S.; Helal, D.; Crochet, M.

2001-01-01

In the present work, we propose a frequency-domain interferometric imaging (FII) technique for a better knowledge of the vertical distribution of the atmospheric scatterers detected by MST radars. This is an extension of the dual frequency-domain interferometry (FDI) technique to multiple frequencies. Its objective is to reduce the ambiguity (resulting from the use of only two adjacent frequencies), inherent with the FDI technique. Different methods, commonly used in antenna array processing, are first described within the context of application to the FII technique. These methods are the Fourier-based imaging, the Capon's and the singular value decomposition method used with the MUSIC algorithm. Some preliminary simulations and tests performed on data collected with the middle and upper atmosphere (MU) radar (Shigaraki, Japan) are also presented. This work is a first step in the developments of the FII technique which seems to be very promising.

Fusion of Multi-Temporal Interferometric Coherence and Optical Image Data for the 2016 Kumamoto Earthquake Damage Assessment

Directory of Open Access Journals (Sweden)

Nopphawan Tamkuan

2017-06-01

Full Text Available Earthquakes are one of the most devastating types of natural disasters, and happen with little to no warning. This study combined Landsat-8 and interferometric ALOS-2 coherence data without training area techniques by classifying the remote sensing ratios of specific features for damage assessment. Waterbodies and highly vegetated areas were extracted by the modified normalized difference water index (MNDWI and normalized difference vegetation index (NDVI, respectively, from after-earthquake images in order to improve the accuracy of damage maps. Urban areas were classified from pre-event interferometric coherence data. The affected areas from the earthquake were detected with the normalized difference (ND between the pre- and co-event interferometric coherence. The results presented three damage types; namely, damage to buildings caused by ground motion, liquefaction, and landslides. The overall accuracy (94% of the confusion matrix was excellent. Results for urban areas were divided into three damage levels (e.g., none–slight, slight–heavy, heavy–destructive at a high (90% overall accuracy level. Moreover, data on buildings damaged by liquefaction and landslides were in good agreement with field survey information. Overall, this study illustrates an effective damage assessment mapping approach that can support post-earthquake management activities for future events, especially in areas where geographical data are sparse.

Pulse retrieval algorithm for interferometric frequency-resolved optical gating based on differential evolution.

Science.gov (United States)

Hyyti, Janne; Escoto, Esmerando; Steinmeyer, Günter

2017-10-01

A novel algorithm for the ultrashort laser pulse characterization method of interferometric frequency-resolved optical gating (iFROG) is presented. Based on a genetic method, namely, differential evolution, the algorithm can exploit all available information of an iFROG measurement to retrieve the complex electric field of a pulse. The retrieval is subjected to a series of numerical tests to prove the robustness of the algorithm against experimental artifacts and noise. These tests show that the integrated error-correction mechanisms of the iFROG method can be successfully used to remove the effect from timing errors and spectrally varying efficiency in the detection. Moreover, the accuracy and noise resilience of the new algorithm are shown to outperform retrieval based on the generalized projections algorithm, which is widely used as the standard method in FROG retrieval. The differential evolution algorithm is further validated with experimental data, measured with unamplified three-cycle pulses from a mode-locked Ti:sapphire laser. Additionally introducing group delay dispersion in the beam path, the retrieval results show excellent agreement with independent measurements with a commercial pulse measurement device based on spectral phase interferometry for direct electric-field retrieval. Further experimental tests with strongly attenuated pulses indicate resilience of differential-evolution-based retrieval against massive measurement noise.

Surface stability test plan for protective barriers

International Nuclear Information System (INIS)

Ligotke, M.W.

1989-01-01

Natural-material protective barriers for long-term isolation of buried waste have been identified as integral components of a plan to isolate a number of Hanford defense waste sites. Standards currently being developed for internal and external barrier performance will mandate a barrier surface layer that is resistant to the eolian erosion processes of wind erosion (deflation) and windborne particle deposition (formation of sand dunes). Thus, experiments are needed to measure rates of eolian erosion processes impacting those surfaces under different surface and climatological conditions. Data from these studies will provide information for use in the evaluation of selected surface layers as a means of providing stable cover over waste sites throughout the design life span of protective barriers. The multi-year test plan described in this plan is directed at understanding processes of wind erosion and windborne particle deposition, providing measurements of erosion rates for models, and suggesting construction materials and methods for reducing the effect of long-term eolian erosion on the barrier. Specifically, this plan describes possible methods to measure rates of eolian erosion, including field and laboratory procedure. Advantages and disadvantages of laboratory (wind tunnel) tests are discussed, and continued wind tunnel tests are recommended for wind erosion studies. A comparison between field and wind tunnel erosive forces is discussed. Plans for testing surfaces are described. Guidance is also presented for studying the processes controlling sand dune and blowout formation. 24 refs., 7 figs., 3 tabs

An Axial Sliding Test for machine elements surfaces

DEFF Research Database (Denmark)

Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

2012-01-01

are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional and a fine......Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder...... liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve...

Mitigation of defocusing by statics and near-surface velocity errors by interferometric least-squares migration with a reference datum

KAUST Repository

Sinha, Mrinal

2016-05-23

Imaging seismic data with an erroneous migration velocity can lead to defocused migration images. To mitigate this problem, we first choose a reference reflector whose topography is well-known from the well logs, for example. Reflections from this reference layer are correlated with the traces associated with reflections from deeper interfaces to get crosscorrelograms. Interferometric least-squares migration (ILSM) is then used to get the migration image that maximizes the crosscorrelation between the observed and the predicted crosscorrelograms. Deeper reference reflectors are used to image deeper parts of the subsurface with a greater accuracy. Results on synthetic and field data show that defocusing caused by velocity errors is largely suppressed by ILSM. We have also determined that ILSM can be used for 4D surveys in which environmental conditions and acquisition parameters are significantly different from one survey to the next. The limitations of ILSM are that it requires prior knowledge of a reference reflector in the subsurface and the velocity model below the reference reflector should be accurate.

Symmetry evaluation for an interferometric fiber optic gyro coil utilizing a bidirectional distributed polarization measurement system.

Science.gov (United States)

Peng, Feng; Li, Chuang; Yang, Jun; Hou, Chengcheng; Zhang, Haoliang; Yu, Zhangjun; Yuan, Yonggui; Li, Hanyang; Yuan, Libo

2017-07-10

We propose a dual-channel measurement system for evaluating the optical path symmetry of an interferometric fiber optic gyro (IFOG) coil. Utilizing a bidirectional distributed polarization measurement system, the forward and backward transmission performances of an IFOG coil are characterized simultaneously by just a one-time measurement. The simple but practical configuration is composed of a bidirectional Mach-Zehnder interferometer and multichannel transmission devices connected to the IFOG coil under test. The static and dynamic temperature results of the IFOG coil reveal that its polarization-related symmetric properties can be effectively obtained with high accuracy. The optical path symmetry investigation is highly beneficial in monitoring and improving the winding technology of an IFOG coil and reducing the nonreciprocal effect of an IFOG.

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Low-redundancy linear arrays in mirrored interferometric aperture synthesis.

Science.gov (United States)

Zhu, Dong; Hu, Fei; Wu, Liang; Li, Jun; Lang, Liang

2016-01-15

Mirrored interferometric aperture synthesis (MIAS) is a novel interferometry that can improve spatial resolution compared with that of conventional IAS. In one-dimensional (1-D) MIAS, antenna array with low redundancy has the potential to achieve a high spatial resolution. This Letter presents a technique for the direct construction of low-redundancy linear arrays (LRLAs) in MIAS and derives two regular analytical patterns that can yield various LRLAs in short computation time. Moreover, for a better estimation of the observed scene, a bi-measurement method is proposed to handle the rank defect associated with the transmatrix of those LRLAs. The results of imaging simulation demonstrate the effectiveness of the proposed method.

Detection and classification of orange peel on polished steel surfaces by interferometric microscopy

International Nuclear Information System (INIS)

2T Research GmbH, Viktor Kaplan Strasse 2, Wiener Neustadt 2700 (Austria))" data-affiliation=" (AC2T Research GmbH, Viktor Kaplan Strasse 2, Wiener Neustadt 2700 (Austria))" >Miranda-Medina, M L; 2T Research GmbH, Viktor Kaplan Strasse 2, Wiener Neustadt 2700 (Austria))" data-affiliation=" (AC2T Research GmbH, Viktor Kaplan Strasse 2, Wiener Neustadt 2700 (Austria))" >Somkuti, P; 2T Research GmbH, Viktor Kaplan Strasse 2, Wiener Neustadt 2700 (Austria))" data-affiliation=" (AC2T Research GmbH, Viktor Kaplan Strasse 2, Wiener Neustadt 2700 (Austria))" >Steiger, B

2013-01-01

In this work, we provide a general description of the so-called orange peel defect produced on polished steel surfaces. By characterizing a prototype set of samples with various degrees orange peel, we attempt to create a simple model that allows the classification of additional samples through the study of surface parameters. On those surfaces, the orange peel structure has roughness amplitudes in the nanometer range. Detecting surface features on that range requires the implementation of a high-precision technique, such as phase shifting interferometry (PSI). Therefore, we can contribute to the improvement of the manufacturing of polished steel surfaces as well as to the quality control by using optical techniques.

All-optical phase modulation for integrated interferometric biosensors.

Science.gov (United States)

Dante, Stefania; Duval, Daphné; Sepúlveda, Borja; González-Guerrero, Ana Belen; Sendra, José Ramón; Lechuga, Laura M

2012-03-26

We present the theoretical and the experimental implementation of an all-optical phase modulation system in integrated Mach-Zehnder Interferometers to solve the drawbacks related to the periodic nature of the interferometric signal. Sensor phase is tuned by modulating the emission wavelength of low-cost commercial laser diodes by changing their output power. FFT deconvolution of the signal allows for direct phase readout, immune to sensitivity variations and to light intensity fluctuations. This simple phase modulation scheme increases the signal-to-noise ratio of the measurements in one order of magnitude, rendering in a sensor with a detection limit of 1.9·10⁻⁷ RIU. The viability of the all-optical modulation approach is demonstrated with an immunoassay detection as a biosensing proof of concept.

ATLAS superconducting solenoid on-surface test

CERN Document Server

Ruber, Roger J M Y; Doi, Y; Haruyama, T; Haug, F; ten Kate, H H J; Kawai, M; Kondo, T; Kondo, Y; Makida, Y; Mizumaki, S; Olesen, G; Pavlov, O V; Pezzetti, M; Pirotte, O; Sbrissa, E; Yamamoto, A

2005-01-01

The ATLAS detector is presently under construction as one of the five LHC experiment set-ups. It relies on a sophisticated magnet system for the momentum measurement of charged particle tracks. The superconducting solenoid is at the center of the detector, the magnet system part nearest to the proton-proton collision point. It is designed for a 2 Tesla strong axial magnetic field at the collision point, while its thin-walled construction of 0.66 radiation lengths avoids degradation of energy measurements in the outer calorimeters. The solenoid and calorimeter have been integrated in their common cryostat, cooled down and tested on-surface. We review the on-surface set-up and report the performance test results.

Interferometric diameters of five evolved intermediate-mass planet-hosting stars measured with PAVO at the CHARA Array

Science.gov (United States)

White, T. R.; Huber, D.; Mann, A. W.; Casagrande, L.; Grunblatt, S. K.; Justesen, A. B.; Silva Aguirre, V.; Bedding, T. R.; Ireland, M. J.; Schaefer, G. H.; Tuthill, P. G.

2018-04-01

Debate over the planet occurrence rates around intermediate-mass stars has hinged on the accurate determination of masses of evolved stars, and has been exacerbated by a paucity of reliable, directly-measured fundamental properties for these stars. We present long-baseline optical interferometry of five evolved intermediate-mass (˜ 1.5 M⊙) planet-hosting stars using the PAVO beam combiner at the CHARA Array, which we combine with bolometric flux measurements and parallaxes to determine their radii and effective temperatures. We measured the radii and effective temperatures of 6 Lyncis (5.12±0.16 R⊙, 4949±58 K), 24 Sextantis (5.49±0.18 R⊙, 4908±65 K), κ Coronae Borealis (4.77±0.07 R⊙, 4870±47 K), HR 6817 (4.45±0.08 R⊙, 5013±59 K), and HR 8641 (4.91±0.12 R⊙, 4950±68 K). We find disagreements of typically 15 % in angular diameter and ˜ 200 K in temperature compared to interferometric measurements in the literature, yet good agreement with spectroscopic and photometric temperatures, concluding that the previous interferometric measurements may have been affected by systematic errors exceeding their formal uncertainties. Modelling based on BaSTI isochrones using various sets of asteroseismic, spectroscopic, and interferometric constraints tends to favour slightly (˜ 15 %) lower masses than generally reported in the literature.

Modified alignment CGHs for aspheric surface test

Science.gov (United States)

Song, Jae-Bong; Yang, Ho-Soon; Rhee, Hyug-Gyo; Lee, Yun-Woo

2009-08-01

Computer Generated Holograms (CGH) for optical test are commonly consisted of one main pattern for testing aspheric surface and some alignment patterns for aligning the interferometer, CGH, and the test optics. To align the CGH plate and the test optics, we designed the alignment CGHs modified from the cat's eye alignment method, which are consisted of a couple of CGH patterns. The incident beam passed through the one part of the alignment CGH pattern is focused onto the one radius position of the test aspheric surface, and is reflected to the other part, and vice versa. This method has several merits compared to the conventional cat's eye alignment method. First, this method can be used in testing optics with a center hole, and the center part of CGH plate can be assigned to the alignment pattern. Second, the alignment pattern becomes a concentric circular arc pattern. The whole CGH patterns including the main pattern and alignment patterns are consisted of only concentric circular fringes. This concentric circular pattern can be easily made by the polar coordinated writer with circular scanning. The required diffraction angle becomes relatively small, so the 1st order diffraction beams instead of the 3rd order diffraction beam can be used as alignment beams, and the visibility can be improved. This alignment method also is more sensitive to the tilt and the lateral shift of the test aspheric surface. Using this alignment pattern, a 200 mm diameter F/0.5 aspheric mirror and a 600 mm diameter F/0.9 mirror were tested.

Flight testing of a luminescent surface pressure sensor

Science.gov (United States)

Mclachlan, B. G.; Bell, J. H.; Espina, J.; Gallery, J.; Gouterman, M.; Demandante, C. G. N.; Bjarke, L.

1992-01-01

NASA ARC has conducted flight tests of a new type of aerodynamic pressure sensor based on a luminescent surface coating. Flights were conducted at the NASA ARC-Dryden Flight Research Facility. The luminescent pressure sensor is based on a surface coating which, when illuminated with ultraviolet light, emits visible light with an intensity dependent on the local air pressure on the surface. This technique makes it possible to obtain pressure data over the entire surface of an aircraft, as opposed to conventional instrumentation, which can only make measurements at pre-selected points. The objective of the flight tests was to evaluate the effectiveness and practicality of a luminescent pressure sensor in the actual flight environment. A luminescent pressure sensor was installed on a fin, the Flight Test Fixture (FTF), that is attached to the underside of an F-104 aircraft. The response of one particular surface coating was evaluated at low supersonic Mach numbers (M = 1.0-1.6) in order to provide an initial estimate of the sensor's capabilities. This memo describes the test approach, the techniques used, and the pressure sensor's behavior under flight conditions. A direct comparison between data provided by the luminescent pressure sensor and that produced by conventional pressure instrumentation shows that the luminescent sensor can provide quantitative data under flight conditions. However, the test results also show that the sensor has a number of limitations which must be addressed if this technique is to prove useful in the flight environment.

Disturbance induced by surface preparation on instrumented indentation test

International Nuclear Information System (INIS)

Li, Yugang; Kanouté, Pascale; François, Manuel

2015-01-01

Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h max (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease

Disturbance induced by surface preparation on instrumented indentation test

Energy Technology Data Exchange (ETDEWEB)

Li, Yugang, E-mail: yugang.li@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); Kanouté, Pascale, E-mail: pascale.kanoute@onera.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); The French Aerospace Lab (ONERA), DMSM/MCE, 29 avenue de la Division Leclerc-BP 72, F-92322 Chatillon Cedex (France); François, Manuel, E-mail: manuel.francois@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France)

2015-08-26

Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h{sub max} (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease.

Fusion of space-borne multi-baseline and multi-frequency interferometric results based on extended Kalman filter to generate high quality DEMs

Science.gov (United States)

Zhang, Xiaojie; Zeng, Qiming; Jiao, Jian; Zhang, Jingfa

2016-01-01

Repeat-pass Interferometric Synthetic Aperture Radar (InSAR) is a technique that can be used to generate DEMs. But the accuracy of InSAR is greatly limited by geometrical distortions, atmospheric effect, and decorrelations, particularly in mountainous areas, such as western China where no high quality DEM has so far been accomplished. Since each of InSAR DEMs generated using data of different frequencies and baselines has their own advantages and disadvantages, it is therefore very potential to overcome some of the limitations of InSAR by fusing Multi-baseline and Multi-frequency Interferometric Results (MMIRs). This paper proposed a fusion method based on Extended Kalman Filter (EKF), which takes the InSAR-derived DEMs as states in prediction step and the flattened interferograms as observations in control step to generate the final fused DEM. Before the fusion, detection of layover and shadow regions, low-coherence regions and regions with large height error is carried out because MMIRs in these regions are believed to be unreliable and thereafter are excluded. The whole processing flow is tested with TerraSAR-X and Envisat ASAR datasets. Finally, the fused DEM is validated with ASTER GDEM and national standard DEM of China. The results demonstrate that the proposed method is effective even in low coherence areas.

A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval

Science.gov (United States)

Wapenaar, Kees; Thorbecke, Jan; van der Neut, Joost

2016-04-01

Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's function of the wave equation without a singularity on the right-hand side) is represented by a closed boundary integral. In practical applications, sources and/or receivers are usually present only on an open surface, which implies that a significant part of the closed boundary integral is by necessity ignored. Here we derive a homogeneous Green's function representation for the common situation that sources and/or receivers are present on an open surface only. We modify the integrand in such a way that it vanishes on the part of the boundary where no sources and receivers are present. As a consequence, the remaining integral along the open surface is an accurate single-sided representation of the homogeneous Green's function. This single-sided representation accounts for all orders of multiple scattering. The new representation significantly improves the aforementioned wavefield imaging applications, particularly in situations where the first-order scattering approximation breaks down.

Time-delay interferometric ranging for space-borne gravitational-wave detectors

International Nuclear Information System (INIS)

Tinto, Massimo; Vallisneri, Michele; Armstrong, J.W.

2005-01-01

Space-borne interferometric gravitational-wave detectors, sensitive in the low-frequency (mHz) band, will fly in the next decade. In these detectors, the spacecraft-to-spacecraft light-travel times will necessarily be unequal and time varying, and (because of aberration) will have different values on up- and down-links. In such unequal-armlength interferometers, laser-phase noise will be canceled by taking linear combinations of the laser-phase observables measured between pairs of spacecraft, appropriately time shifted by the light propagation times along the corresponding arms. This procedure, known as time-delay interferometry (TDI), requires an accurate knowledge of the light-time delays as functions of time. Here we propose a high-accuracy technique to estimate these time delays, and we study its use in the context of the Laser Interferometer Space Antenna (LISA) mission. We refer to this ranging technique, which relies on the TDI combinations themselves, as time-delay interferometric ranging (TDIR). For every TDI combination, we show that, by minimizing the rms power in that combination (averaged over integration times ∼10 4 s) with respect to the time-delay parameters, we obtain estimates of the time delays accurate enough to cancel laser noise to a level well below the secondary noises. Thus TDIR allows the implementation of TDI without the use of dedicated interspacecraft ranging systems, with a potential simplification of the LISA design. In this paper we define the TDIR procedure formally, and we characterize its expected performance via simulations with the Synthetic LISA software package

Comparing interferometry techniques for multi-degree of freedom test mass readout

International Nuclear Information System (INIS)

Isleif, Katharina-Sophie; Gerberding, Oliver; Mehmet, Moritz; Schwarze, Thomas S; Heinzel, Gerhard; Danzmann, Karsten

2016-01-01

Laser interferometric readout systems with 1pm/Hz precision over long time scales have successfully been developed for LISA and LISA Pathfinder. Future gravitational physics experiments, for example in the fields of gravitational wave detection and geodesy, will potentially require similar levels of displacement and tilt readouts of multiple test masses in multiple degrees of freedom. In this article we compare currently available classic interferometry schemes with new techniques using phase modulations and complex readout algorithms. Based on a simple example we show that the new techniques have great potential to simplify interferometric readouts. (paper)

Testing of newly developed functional surfaces under pure sliding conditions

DEFF Research Database (Denmark)

Godi, Alessandro; Mohaghegh, Kamran; Grønbæk, J.

2013-01-01

the surfaces in an industrial context. In this paper, a number of experimental tests were performed using a novel test rig, called axial sliding test, simulating the contact of surfaces under pure sliding conditions. The aim of the experiments is to evaluate the frictional behavior of a new typology...... of textured surfaces, the so-called multifunctional surfaces, characterized by a plateau area able to bear loads and a deterministic pattern of lubricant pockets. Six surface typologies, namely three multifunctional and three machined using classical processes, were chosen to slide against a mirror....... The results comparison showed clearly how employing multifunctional surfaces can reduce friction forces up to 50 % at high normal loads compared to regularly ground or turned surfaces. Friction coefficients approximately equal to 0.12 were found for classically machined surfaces, whereas the values were 0...

Methane Lunar Surface Thermal Control Test

Science.gov (United States)

Plachta, David W.; Sutherlin, Steven G.; Johnson, Wesley L.; Feller, Jeffrey R.; Jurns, John M.

2012-01-01

NASA is considering propulsion system concepts for future missions including human return to the lunar surface. Studies have identified cryogenic methane (LCH4) and oxygen (LO2) as a desirable propellant combination for the lunar surface ascent propulsion system, and they point to a surface stay requirement of 180 days. To meet this requirement, a test article was prepared with state-of-the-art insulation and tested in simulated lunar mission environments at NASA GRC. The primary goals were to validate design and models of the key thermal control technologies to store unvented methane for long durations, with a low-density high-performing Multi-layer Insulation (MLI) system to protect the propellant tanks from the environmental heat of low Earth orbit (LEO), Earth to Moon transit, lunar surface, and with the LCH4 initially densified. The data and accompanying analysis shows this storage design would have fallen well short of the unvented 180 day storage requirement, due to the MLI density being much higher than intended, its substructure collapse, and blanket separation during depressurization. Despite the performance issue, insight into analytical models and MLI construction was gained. Such modeling is important for the effective design of flight vehicle concepts, such as in-space cryogenic depots or in-space cryogenic propulsion stages.

Test case for a near-surface repository

International Nuclear Information System (INIS)

Elert, M.; Jones, C.; Nilsson, L.B.; Skagius, K.; Wiborgh, M.

1998-01-01

A test case is presented for assessment of a near-surface disposal facility for radioactive waste. The case includes waste characterization and repository design, requirements and constraints in an assessment context, scenario development, model description and test calculations

Interferometric scattering (iSCAT) microscopy: studies of biological membrane dynamics

Science.gov (United States)

Reina, Francesco; Galiani, Silvia; Shrestha, Dilip; Sezgin, Erdinc; Lagerholm, B. Christoffer; Cole, Daniel; Kukura, Philipp; Eggeling, Christian

2018-02-01

The study of the organization and dynamics of molecules in model and cellular membranes is an important topic in contemporary biophysics. Imaging and single particle tracking in this particular field, however, proves particularly demanding, as it requires simultaneously high spatio-temporal resolution and high signal-to-noise ratios. A remedy to this challenge might be Interferometric Scattering (iSCAT) microscopy, due to its fast sampling rates, label-free imaging capabilities and, most importantly, tuneable signal level output. Here we report our recent advances in the imaging and molecular tracking on phase-separated model membrane systems and live-cell membranes using this technique.

Three-dimensional Reconstruction Method Study Based on Interferometric Circular SAR

Directory of Open Access Journals (Sweden)

Hou Liying

2016-10-01

Full Text Available Circular Synthetic Aperture Radar (CSAR can acquire targets’ scattering information in all directions by a 360° observation, but a single-track CSAR cannot efficiently obtain height scattering information for a strong directive scatter. In this study, we examine the typical target of the three-dimensional circular SAR interferometry theoryand validate the theory in a darkroom experiment. We present a 3D reconstruction of the actual tank metal model of interferometric CSAR for the first time, verify the validity of the method, and demonstrate the important potential applications of combining 3D reconstruction with omnidirectional observation.

Standard Test Method for Hydrophobic Surface Films by the Atomizer Test

CERN Document Server

American Society for Testing and Materials. Philadelphia

1965-01-01

1.1 This test method covers the detection of the presence of hydrophobic (nonwetting) films on surfaces and the presence of hydrophobic organic materials in processing ambients. When properly conducted, the test will enable detection of fractional molecular layers of hydrophobic organic contaminants. On very rough or porous surfaces the sensitivity of the test may be significantly decreased. 1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Calibration Errors in Interferometric Radio Polarimetry

Science.gov (United States)

Hales, Christopher A.

2017-08-01

Residual calibration errors are difficult to predict in interferometric radio polarimetry because they depend on the observational calibration strategy employed, encompassing the Stokes vector of the calibrator and parallactic angle coverage. This work presents analytic derivations and simulations that enable examination of residual on-axis instrumental leakage and position-angle errors for a suite of calibration strategies. The focus is on arrays comprising alt-azimuth antennas with common feeds over which parallactic angle is approximately uniform. The results indicate that calibration schemes requiring parallactic angle coverage in the linear feed basis (e.g., the Atacama Large Millimeter/submillimeter Array) need only observe over 30°, beyond which no significant improvements in calibration accuracy are obtained. In the circular feed basis (e.g., the Very Large Array above 1 GHz), 30° is also appropriate when the Stokes vector of the leakage calibrator is known a priori, but this rises to 90° when the Stokes vector is unknown. These findings illustrate and quantify concepts that were previously obscure rules of thumb.

Tunable coupled surface acoustic cavities

Science.gov (United States)

de Lima, M. M.; Santos, P. V.; Kosevich, Yu. A.; Cantarero, A.

2012-06-01

We demonstrate the electric tuning of the acoustic field in acoustic microcavities (MCs) defined by a periodic arrangement of metal stripes within a surface acoustic delay line on LiNbO3 substrate. Interferometric measurements show the enhancement of the acoustic field distribution within a single MC, the presence of a "bonding" and "anti-bonding" modes for two strongly coupled MCs, as well as the positive dispersion of the "mini-bands" formed by five coupled MCs. The frequency and amplitude of the resonances can be controlled by the potential applied to the metal stripes.

Computational adaptive optics for broadband interferometric tomography of tissues and cells

Science.gov (United States)

Adie, Steven G.; Mulligan, Jeffrey A.

2016-03-01

Adaptive optics (AO) can shape aberrated optical wavefronts to physically restore the constructive interference needed for high-resolution imaging. With access to the complex optical field, however, many functions of optical hardware can be achieved computationally, including focusing and the compensation of optical aberrations to restore the constructive interference required for diffraction-limited imaging performance. Holography, which employs interferometric detection of the complex optical field, was developed based on this connection between hardware and computational image formation, although this link has only recently been exploited for 3D tomographic imaging in scattering biological tissues. This talk will present the underlying imaging science behind computational image formation with optical coherence tomography (OCT) -- a beam-scanned version of broadband digital holography. Analogous to hardware AO (HAO), we demonstrate computational adaptive optics (CAO) and optimization of the computed pupil correction in 'sensorless mode' (Zernike polynomial corrections with feedback from image metrics) or with the use of 'guide-stars' in the sample. We discuss the concept of an 'isotomic volume' as the volumetric extension of the 'isoplanatic patch' introduced in astronomical AO. Recent CAO results and ongoing work is highlighted to point to the potential biomedical impact of computed broadband interferometric tomography. We also discuss the advantages and disadvantages of HAO vs. CAO for the effective shaping of optical wavefronts, and highlight opportunities for hybrid approaches that synergistically combine the unique advantages of hardware and computational methods for rapid volumetric tomography with cellular resolution.

Application of optical interferometric techniques for non-destructive evaluation of novel "green" composite materials

Science.gov (United States)

Pagliarulo, Vito; Russo, Pietro; Bianco, Vittorio; Ferraro, Pietro; Simeoli, Giorgio; Cimino, Francesca; Ruggiero, Berardo

2018-04-01

Nowadays the use of advanced composite materials in aeronautics, both civil and military, in automotive and in sport applications, citing some, is well established. The characteristics of composite materials in terms of weight, fatigue resistance and corrosion resistance make them competitive with respect to conventional ones. On the other side, the fabrication process of the most employed composites reinforced by carbon fibers or glass fibers, needs of complex steps that not always are environmental complaisant. Moreover, such fibers are not themselves "green". For these reasons, in the last decades, the use of natural reinforcing fibers has gained an increasing attention allowing the development of new materials with the same advantages of composite systems but respecting the environment. Furthermore, such materials for their structural complexity are not always compatible with the use of standard non-destructive evaluation as the ultrasounds methods. In this work the efficiency of the employment of optical interferometric techniques as nondestructive evaluation methods in full field modality is proved on novel "green" composite materials. In particular, Electronic Speckle Pattern Interferometry has been tested on different kinds of specimens after flexural tests.

Application of holographic interferometric studies of underwater shock-wave focusing to medicine

Science.gov (United States)

Takayama, Kazuyoshi; Nagoya, H.; Obara, Tetsuro; Kuwahara, M.

1993-01-01

Holographic interferometric flow visualization was successfully applied to underwater shock wave focusing and its application to extracorporeal shock wave lithotripsy (ESWL). Real time diffuse holograms revealed the shock wave focusing process in an ellipsoidal reflector made from PMMA and double exposure holographic interferometry also clarified quantitatively the shock focusing process. Disintegration of urinary tract stones and gallbladder stones was observed by high speed photogrammetry. Tissue damage associated with the ESWL treatment is discussed in some detail.

Comparison of interferometric and stereo-radargrammetric 3D metrics in mapping of forest resources

Science.gov (United States)

Karila, K.; Karjalainen, M.; Yu, X.; Vastaranta, M.; Holopainen, M.; Hyyppa, J.

2015-04-01

Accurate forest resources maps are needed in diverse applications ranging from the local forest management to the global climate change research. In particular, it is important to have tools to map changes in forest resources, which helps us to understand the significance of the forest biomass changes in the global carbon cycle. In the task of mapping changes in forest resources for wide areas, Earth Observing satellites could play the key role. In 2013, an EU/FP7-Space funded project "Advanced_SAR" was started with the main objective to develop novel forest resources mapping methods based on the fusion of satellite based 3D measurements and in-situ field measurements of forests. During the summer 2014, an extensive field surveying campaign was carried out in the Evo test site, Southern Finland. Forest inventory attributes of mean tree height, basal area, mean stem diameter, stem volume, and biomass, were determined for 91 test plots having the size of 32 by 32 meters (1024 m2). Simultaneously, a comprehensive set of satellite and airborne data was collected. Satellite data also included a set of TanDEM-X (TDX) and TerraSAR-X (TSX) X-band synthetic aperture radar (SAR) images, suitable for interferometric and stereo-radargrammetric processing to extract 3D elevation data representing the forest canopy. In the present study, we compared the accuracy of TDX InSAR and TSX stereo-radargrammetric derived 3D metrics in forest inventory attribute prediction. First, 3D data were extracted from TDX and TSX images. Then, 3D data were processed as elevations above the ground surface (forest canopy height values) using an accurate Digital Terrain Model (DTM) based on airborne laser scanning survey. Finally, 3D metrics were calculated from the canopy height values for each test plot and the 3D metrics were compared with the field reference data. The Random Forest method was used in the forest inventory attributes prediction. Based on the results InSAR showed slightly better

Remotely Sensed Active Layer Thickness (ReSALT at Barrow, Alaska Using Interferometric Synthetic Aperture Radar

Directory of Open Access Journals (Sweden)

Kevin Schaefer

2015-03-01

Full Text Available Active layer thickness (ALT is a critical parameter for monitoring the status of permafrost that is typically measured at specific locations using probing, in situ temperature sensors, or other ground-based observations. Here we evaluated the Remotely Sensed Active Layer Thickness (ReSALT product that uses the Interferometric Synthetic Aperture Radar technique to measure seasonal surface subsidence and infer ALT around Barrow, Alaska. We compared ReSALT with ground-based ALT obtained using probing and calibrated, 500 MHz Ground Penetrating Radar at multiple sites around Barrow. ReSALT accurately reproduced observed ALT within uncertainty of the GPR and probing data in ~76% of the study area. However, ReSALT was less than observed ALT in ~22% of the study area with well-drained soils and in ~1% of the area where soils contained gravel. ReSALT was greater than observed ALT in some drained thermokarst lake basins representing ~1% of the area. These results indicate remote sensing techniques based on InSAR could be an effective way to measure and monitor ALT over large areas on the Arctic coastal plain.

Test case for a near-surface repository

Energy Technology Data Exchange (ETDEWEB)

Elert, M.; Jones, C. [Kemakta Konsult AB, Stockholm (Sweden); Nilsson, L.B. [Swedish Nuclear Fuel and Waste Co, Stockholm (Sweden); Skagius, K.; Wiborgh, M. [Kemakta Konsult AB, Stockholm (Sweden)

1998-09-01

A test case is presented for assessment of a near-surface disposal facility for radioactive waste. The case includes waste characterization and repository design, requirements and constraints in an assessment context, scenario development, model description and test calculations 6 refs, 12 tabs, 16 figs

Comparison of broad band time series recorded parallel by FGI type interferometric water level and Lippmann type pendulum tilt meters at Conrad observatory, Austria

Science.gov (United States)

Ruotsalainen, Hannu; Papp, Gabor; Leonhardt, Roman; Ban, Dora; Szücs, Eszter; Benedek, Judith

2016-04-01

The Finnish Geodetic Institute (FGI) the progenitor of Finnish Geospatial Research Institute of NLS designed and built a 5.5m long prototype of interferometric water level tiltmeter (iWT) in early 2014. Geodetic and Geophysical Institute (GGI), Sopron, Hungary bought the instrument and started tilt measurement in August 2014 at the Conrad observatory (COBS), Austria to monitor geodynamical phenomena like microseisms, free oscillations of the Earth, earth tides, mass loading effects and crustal deformations in cooperation with Austrian Central Institute for Meteorology and Geodynamics (ZAMG) and the FGI. On the July 16 2015 a Lippmann-type 2D tilt sensor (LTS) was also installed by GGI on the 6 m long pier where iWT was set up previously. This situation opens a possibility to do broad band (from secular to seismic variations up to 15 Hz) geophysical signal analysis comparing the responses of long (several meters) and short (a few decimeters) base instruments implementing different physical principles (relative height change of a level surface and inclination change of the plumb line). The characteristics of the sensors are studied by the evaluation of the spectra of recorded signals dominated by microseisms. The iWT has internal interferometric calibration and it can be compared to Lippmanns tilt meter one. Both instruments show good long term ( > 1 day) stability when earth tides and ocean and air mass loading tilts are modelled.

THE RRAT TRAP: INTERFEROMETRIC LOCALIZATION OF RADIO PULSES FROM J0628+0909

International Nuclear Information System (INIS)

Law, Casey J.; Bower, Geoffrey C.; Pokorny, Martin; Rupen, Michael P.; Sowinski, Ken

2012-01-01

We present the first blind interferometric detection and imaging of a millisecond radio transient with an observation of transient pulsar J0628+0909. We developed a special observing mode of the Karl G. Jansky Very Large Array to produce correlated data products (i.e., visibilities and images) on a timescale of 10 ms. Correlated data effectively produce thousands of beams on the sky that can localize sources anywhere over a wide field of view. We used this new observing mode to find and image pulses from the rotating radio transient (RRAT) J0628+0909, improving its localization by two orders of magnitude. Since the location of the RRAT was only approximately known when first observed, we searched for transients using a wide-field detection algorithm based on the bispectrum, an interferometric closure quantity. Over 16 minutes of observing, this algorithm detected one transient offset roughly 1' from its nominal location; this allowed us to image the RRAT to localize it with an accuracy of 1.''6. With a priori knowledge of the RRAT location, a traditional beam-forming search of the same data found two lower significance pulses. The refined RRAT position excludes all potential multiwavelength counterparts, limiting its optical luminosity to L i ' 31 erg s –1 and disfavoring source models with luminous neutron stars.

THE RRAT TRAP: INTERFEROMETRIC LOCALIZATION OF RADIO PULSES FROM J0628+0909

Energy Technology Data Exchange (ETDEWEB)

Law, Casey J.; Bower, Geoffrey C. [Department of Astronomy and Radio Astronomy Lab, University of California, Berkeley, CA (United States); Pokorny, Martin; Rupen, Michael P.; Sowinski, Ken [National Radio Astronomy Observatory, Socorro, NM (United States)

2012-12-01

We present the first blind interferometric detection and imaging of a millisecond radio transient with an observation of transient pulsar J0628+0909. We developed a special observing mode of the Karl G. Jansky Very Large Array to produce correlated data products (i.e., visibilities and images) on a timescale of 10 ms. Correlated data effectively produce thousands of beams on the sky that can localize sources anywhere over a wide field of view. We used this new observing mode to find and image pulses from the rotating radio transient (RRAT) J0628+0909, improving its localization by two orders of magnitude. Since the location of the RRAT was only approximately known when first observed, we searched for transients using a wide-field detection algorithm based on the bispectrum, an interferometric closure quantity. Over 16 minutes of observing, this algorithm detected one transient offset roughly 1' from its nominal location; this allowed us to image the RRAT to localize it with an accuracy of 1.''6. With a priori knowledge of the RRAT location, a traditional beam-forming search of the same data found two lower significance pulses. The refined RRAT position excludes all potential multiwavelength counterparts, limiting its optical luminosity to L{sub i{sup '}}<1.1 Multiplication-Sign 10{sup 31} erg s{sup -1} and disfavoring source models with luminous neutron stars.

Development of an Interferometric Phased Array Trigger for Balloon-Borne Detection of the Highest Energy Cosmic Particles

Science.gov (United States)

Vieregg, Abigail

interferometric phased array trigger for these impulsive radio detectors, a new type of trigger that will improve sensitivity substantially and expedite the discovery of the highest energy particles in our universe. We have developed an 8- channel interferometric trigger board for ground-based applications that will be deployed in December 2017 with the ground-based Askaryan Radio Array (ARA) experiment at the South Pole. Preliminary Monte Carlo simulations indicate that the cosmogenic neutrino event rate will go up by a factor of 3 with the new trigger. The true power of the interferometric trigger is in scaling to large numbers of channels, and the discovery space that is only available from a balloon platform at the highest energies is extremely appealing. We will build on and extend the NASA investment in the ANITA Long Duration Balloon (LDB) mission and the many other complementary particle astrophysics LDB missions by developing the electronics required to bring a large-scale radio interferometric trigger to a balloon platform, extending the scientific reach of any future LDB or Super Pressure Balloon (SPB) mission for radio detection of the highest energy cosmic particles. We will develop an interferometric trigger system that is scalable to O(100) channels and suitable for use on a balloon platform. Under this proposal, we will: 1) Design and fabricate interferometric trigger hardware for balloon-borne cosmic particle detectors that is scalable to large numbers of channels O(100) by reducing the power consumption per channel, increasing the number of channels per board, and developing high-speed communication capability between boards. 2) Perform a trade study and inform design decisions for future balloon missions by further developing our Monte Carlo simulation and adapting it to balloon geometries.

Interferometric method to determine the Kerr constant of perspex and ZnSe

CSIR Research Space (South Africa)

Govender, P

2010-09-01

Full Text Available , (1999). [2] T. K. Ishii and A. Griffis, “Measurement of electro-optic effects in acrylic plastic”, Microwave and Optical Technology Letters, 4, 387-389(1991). [3] W. Kucharczyk, M. J. Gunning, R. E. Raab and C. Graham, “Interferometric investigation... to Determine the Kerr Constant of Perspex Patricia Govender1, 2, Dr. V.W. Couling1 1 UKZN Pietermaritzburg, King Edward Avenue, Scottsville, Pietermaritzburg 2 CSIR, DPSS, 3Meiring Naude Avenue Patricia Govender e-mail address: pgovender...

The nature of extragalactic radio-jets from high-resolution radio-interferometric observations

OpenAIRE

Perucho, Manel

2014-01-01

Extragalactic jets are a common feature of radio-loud active galaxies. The nature of the observed jets in relation to the bulk flow is still unclear. In particular it is not clear whether the observations of parsec-scale jets using the very long baseline interferometric technique (VLBI) reveal wave-like structures that develop and propagate along the jet, or trace the jet flow itself. In this contribution I review the evidence collected during the last years showing that the ridge-lines of he...

Experimental Verification of a New Model Describing the Influence of Incomplete Signal Extinction Ratio on the Sensitivity Degradation due to Multiple Interferometric Crosstalk

DEFF Research Database (Denmark)

Liu, Fenghai; Rasmussen, Christian Jørgen; Pedersen, Rune Johan Skullerud

1999-01-01

Larger optical penalties than predicted by a Gaussian crosstalk model are found both in our experiments and in the literature when investigating signals including multiple interferometric crosstalk contributions. We attribute this to an imperfect signal extinction ratio. In this letter, simple...... analytical relations for crosstalk induced power penalties are derived taking the signal extinction ratio into account and excellent agreement with 10-Gb/s experiments is obtained. Both theory and experiment show the importance of the signal extinction ratio in connection with interferometric crosstalk....

Redundant interferometric calibration as a complex optimization problem

Science.gov (United States)

Grobler, T. L.; Bernardi, G.; Kenyon, J. S.; Parsons, A. R.; Smirnov, O. M.

2018-05-01

Observations of the redshifted 21 cm line from the epoch of reionization have recently motivated the construction of low-frequency radio arrays with highly redundant configurations. These configurations provide an alternative calibration strategy - `redundant calibration' - and boost sensitivity on specific spatial scales. In this paper, we formulate calibration of redundant interferometric arrays as a complex optimization problem. We solve this optimization problem via the Levenberg-Marquardt algorithm. This calibration approach is more robust to initial conditions than current algorithms and, by leveraging an approximate matrix inversion, allows for further optimization and an efficient implementation (`redundant STEFCAL'). We also investigated using the preconditioned conjugate gradient method as an alternative to the approximate matrix inverse, but found that its computational performance is not competitive with respect to `redundant STEFCAL'. The efficient implementation of this new algorithm is made publicly available.

Advanced Virgo: a second-generation interferometric gravitational wave detector

International Nuclear Information System (INIS)

Acernese, F; Barone, F; Agathos, M; Agatsuma, K; Bauer, Th S; Beker, M G; Aisa, D; Allemandou, N; Allocca, A; Amarni, J; Baronick, J-P; Barsuglia, M; Astone, P; Basti, F; Balestri, G; Ballardin, G; Bavigadda, V; Basti, A; Bejger, M; Belczynski, C

2015-01-01

Advanced Virgo is the project to upgrade the Virgo interferometric detector of gravitational waves, with the aim of increasing the number of observable galaxies (and thus the detection rate) by three orders of magnitude. The project is now in an advanced construction phase and the assembly and integration will be completed by the end of 2015. Advanced Virgo will be part of a network, alongside the two Advanced LIGO detectors in the US and GEO HF in Germany, with the goal of contributing to the early detection of gravitational waves and to opening a new window of observation on the universe. In this paper we describe the main features of the Advanced Virgo detector and outline the status of the construction. (paper)

Enhancing Raman signals with an interferometrically controlled AFM tip

International Nuclear Information System (INIS)

Oron-Carl, Matti; Krupke, Ralph

2013-01-01

We demonstrate the upgrade of a commercial confocal Raman microscope into a tip-enhanced Raman microscope/spectroscopy system (TERS) by integrating an interferometrically controlled atomic force microscope into the base of an existing upright microscope to provide near-field detection and thus signal enhancement. The feasibility of the system is demonstrated by measuring the Raman near-field enhancement on thin PEDOT:PSS films and on carbon nanotubes within a device geometry. An enhancement factor of 2–3 and of 5–6 is observed, respectively. Moreover, on a nanotube device we show local conductivity measurement and its correlation to Raman and topography recordings. Upgrading an existing upright confocal Raman microscope in the demonstrated way is significantly cheaper than purchasing a complete commercial TERS system. (paper)

An airborne interferometric SAR system for high-performance 3D mapping

Science.gov (United States)

Lange, Martin; Gill, Paul

2009-05-01

With a vertical accuracy better than 1 m and collection rates up to 7000 km2/h, airborne interferometric synthetic aperture radars (InSAR) bridge the gap between space borne radar sensors and airborne optical LIDARs. This paper presents the latest generation of X-band InSAR sensors, developed by Intermap TechnologiesTM, which are operated on our four aircrafts. The sensors collect data for the NEXTMap(R) program - a digital elevation model (DEM) with 1 m vertical accuracy for the contiguous U.S., Hawaii, and most of Western Europe. For a successful operation, challenges like reduction of multipath reflections, very high interferometric phase stability, and a precise system calibration had to be mastered. Recent advances in sensor design, comprehensive system automation and diagnostics have increased the sensor reliability to a level where no radar operator is required onboard. Advanced flight planning significantly improved aircraft utilization and acquisition throughput, while reducing operational costs. Highly efficient data acquisition with straight flight lines up to 1200 km is daily routine meanwhile. The collected data pass though our automated processing cluster and finally are edited to our terrain model products. Extensive and rigorous quality control at every step of the workflow are key to maintain stable vertical accuracies of 1 m and horizontal accuracies of 2 m for our 3D maps. The combination of technical and operational advances presented in this paper enabled Intermap to survey two continents, producing 11 million km2 of uniform and accurate 3D terrain data.

Computational adaptive optics for broadband optical interferometric tomography of biological tissue.

Science.gov (United States)

Adie, Steven G; Graf, Benedikt W; Ahmad, Adeel; Carney, P Scott; Boppart, Stephen A

2012-05-08

Aberrations in optical microscopy reduce image resolution and contrast, and can limit imaging depth when focusing into biological samples. Static correction of aberrations may be achieved through appropriate lens design, but this approach does not offer the flexibility of simultaneously correcting aberrations for all imaging depths, nor the adaptability to correct for sample-specific aberrations for high-quality tomographic optical imaging. Incorporation of adaptive optics (AO) methods have demonstrated considerable improvement in optical image contrast and resolution in noninterferometric microscopy techniques, as well as in optical coherence tomography. Here we present a method to correct aberrations in a tomogram rather than the beam of a broadband optical interferometry system. Based on Fourier optics principles, we correct aberrations of a virtual pupil using Zernike polynomials. When used in conjunction with the computed imaging method interferometric synthetic aperture microscopy, this computational AO enables object reconstruction (within the single scattering limit) with ideal focal-plane resolution at all depths. Tomographic reconstructions of tissue phantoms containing subresolution titanium-dioxide particles and of ex vivo rat lung tissue demonstrate aberration correction in datasets acquired with a highly astigmatic illumination beam. These results also demonstrate that imaging with an aberrated astigmatic beam provides the advantage of a more uniform depth-dependent signal compared to imaging with a standard gaussian beam. With further work, computational AO could enable the replacement of complicated and expensive optical hardware components with algorithms implemented on a standard desktop computer, making high-resolution 3D interferometric tomography accessible to a wider group of users and nonspecialists.

Model predictions of the results of interferometric observations for stars under conditions of strong gravitational scattering by black holes and wormholes

Energy Technology Data Exchange (ETDEWEB)

Shatskiy, A. A., E-mail: shatskiy@asc.rssi.ru; Kovalev, Yu. Yu.; Novikov, I. D. [Russian Academy of Sciences, Astro Space Center, Lebedev Physical Institute (Russian Federation)

2015-05-15

The characteristic and distinctive features of the visibility amplitude of interferometric observations for compact objects like stars in the immediate vicinity of the central black hole in our Galaxy are considered. These features are associated with the specifics of strong gravitational scattering of point sources by black holes, wormholes, or black-white holes. The revealed features will help to determine the most important topological characteristics of the central object in our Galaxy: whether this object possesses the properties of only a black hole or also has characteristics unique to wormholes or black-white holes. These studies can be used to interpret the results of optical, infrared, and radio interferometric observations.

Model predictions of the results of interferometric observations for stars under conditions of strong gravitational scattering by black holes and wormholes

International Nuclear Information System (INIS)

Shatskiy, A. A.; Kovalev, Yu. Yu.; Novikov, I. D.

2015-01-01

The characteristic and distinctive features of the visibility amplitude of interferometric observations for compact objects like stars in the immediate vicinity of the central black hole in our Galaxy are considered. These features are associated with the specifics of strong gravitational scattering of point sources by black holes, wormholes, or black-white holes. The revealed features will help to determine the most important topological characteristics of the central object in our Galaxy: whether this object possesses the properties of only a black hole or also has characteristics unique to wormholes or black-white holes. These studies can be used to interpret the results of optical, infrared, and radio interferometric observations

Standard Test Method for Hydrophobic Surface Films by the Water-Break Test

CERN Document Server

American Society for Testing and Materials. Philadelphia

2002-01-01

1.1 This test method covers the detection of the presence of hydrophobic (nonwetting) films on surfaces and the presence of hydrophobic organic materials in processing ambients. When properly conducted, the test will enable detection of molecular layers of hydrophobic organic contaminants. On very rough or porous surfaces, the sensitivity of the test may be significantly decreased. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Surface moisture measurement system acceptance testing work plan

International Nuclear Information System (INIS)

Ritter, G.A.

1996-01-01

This work plan addresses testing of the Surface Moisture Measurement System (SMMS) at the Fuels and Materials Examination Facility (FMEF). The purpose of this plan is to define the scope of work, identify organizational responsibilities, describe test control requirements, and provide estimated costs and schedule associated with acceptance testing

The effects of surface treatments on rapid chloride permeability tests

KAUST Repository

Yoon, Seyoon

2012-08-01

Surface treatments are commonly applied to improve the chloride resistance of concrete structures exposed to saline environments. Information on chloride ingress to surface-treated concrete is mostly provided by application of the rapid chloride permeability test (RCPT); this test is short in duration and provides rapid results. This study presents a numerical formulation, based on the extended Nernst-Plank/Poisson (NPP) equation, to model the effect of the surface treatment on a sample tested by RCPT. Predictions of the model are compared to experimental measurements. The simulations show that the results from RCPT, in terms of ionic profiles and measurement of the electric field, are dependent on the effectiveness of surface treatments. During RCPT, highly effective surface treatments cause both cations and anions to flocculate at the interface between the surface treatment and the concrete, creating a local electric field. Our numerical model includes these phenomena and presents a methodology to obtain more accurate diffusivities of the surface-treated- concrete from RCPT. © 2012 Elsevier B.V. All rights reserved.

The effects of surface treatments on rapid chloride permeability tests

KAUST Repository

Yoon, Seyoon; Oh, Sang-gyun; Ha, Juyoung; Monteiro, Paulo M.

2012-01-01

Surface treatments are commonly applied to improve the chloride resistance of concrete structures exposed to saline environments. Information on chloride ingress to surface-treated concrete is mostly provided by application of the rapid chloride permeability test (RCPT); this test is short in duration and provides rapid results. This study presents a numerical formulation, based on the extended Nernst-Plank/Poisson (NPP) equation, to model the effect of the surface treatment on a sample tested by RCPT. Predictions of the model are compared to experimental measurements. The simulations show that the results from RCPT, in terms of ionic profiles and measurement of the electric field, are dependent on the effectiveness of surface treatments. During RCPT, highly effective surface treatments cause both cations and anions to flocculate at the interface between the surface treatment and the concrete, creating a local electric field. Our numerical model includes these phenomena and presents a methodology to obtain more accurate diffusivities of the surface-treated- concrete from RCPT. © 2012 Elsevier B.V. All rights reserved.

Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

International Nuclear Information System (INIS)

Chiara, P.; Morelli, A.

2010-01-01

The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements.Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken.This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

Science.gov (United States)

Chiara, P.; Morelli, A.

2010-05-01

The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements. Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken. This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-10-15

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

Assembly, alignment and test of the Transiting Exoplanet Survey Satellite (TESS) optical assemblies

Science.gov (United States)

Balonek, Gregory; Brown, Joshua J.; Andre, James E.; Chesbrough, Christian D.; Chrisp, Michael P.; Dalpiaz, Michael; Lennon, Joseph; Richards, B. C.; Clark, Kristin E.

2017-08-01

The Transiting Exoplanet Survey Satellite (TESS) will carry four visible waveband, seven-element, refractive F/1.4 lenses, each with a 34 degree diagonal field of view. This paper describes the methods used for the assembly, alignment and test of the four flight optical assemblies. Prior to commencing the build of the four flight optical assemblies, a Risk Reduction Unit (RRU) was successfully assembled and tested [1]. The lessons learned from the RRU were applied to the build of the flight assemblies. The main modifications to the flight assemblies include the inking of the third lens element stray light mitigation, tighter alignment tolerances, and diamond turning for critical mechanical surfaces. Each of the optical assemblies was tested interferometrically and measured with a low coherence distance measuring interferometer (DMI) to predict the optimal shim thickness between the lens assembly and detector before -75°C environmental testing. In addition to individual test data, environmental test results from prior assemblies allow for the exploration of marginal performance differences between each of the optical assemblies.

Lower frequency companions for the Advanced LIGO gravitational wave interferometric detectors: an observational opportunity?

International Nuclear Information System (INIS)

DeSalvo, Riccardo

2004-01-01

Recent x-ray and optical observations provide evidence for a population of intermediate mass black holes with masses of tens to thousands of solar masses. Dynamical braking in high stellar density regions may 'catalyze' the inspiral of heavy mass objects down to the million-year time scale. Black-hole binaries, with the masses implied by the observations, will plunge below 100 Hz. It may be technologically possible to build ground-based low frequency gravitational wave interferometric detectors optimized to detect these events and install them next to Advanced LIGO (AdL), within the existing LIGO facilities. This additional interferometer, operated coherently with AdL and Virgo, would greatly enhance the effectiveness of the existing interferometers by generating a wealth of triggers for potentially frequent but otherwise undetectable heavy mass inspirals. AdL would study, at higher frequency, the triggered, ultra-relativistic phases (merging and ringdown) of these inspirals. Comparisons are made between the expected detection performances of AdL in its proposed wide band tuning, as well as AdL in its best low frequency tuning, with a low frequency gravitational wave interferometric detector that is mechanically and optically optimized for operation at the lowest possible frequency. Finally, the synergies of tandem operation of AdL and the proposed low frequency interferometer have been considered

Thermal lens and interferometric method for glass transition and thermo physical properties measurements in Nd2O3 doped sodium zincborate glass.

Science.gov (United States)

Astrath, N G C; Steimacher, A; Rohling, J H; Medina, A N; Bento, A C; Baesso, M L; Jacinto, C; Catunda, T; Lima, S M; Karthikeyan, B

2008-12-22

In this work the time resolved thermal lens method is combined with interferometric technique, the thermal relaxation calorimetry, photoluminescence and lifetime measurements to determine the thermo physical properties of Nd(2)O(3) doped sodium zincborate glass as a function of temperature up to the glass transition region. Thermal diffusivity, thermal conductivity, fluorescence quantum efficiency, linear thermal expansion coefficient and thermal coefficient of electronic polarizability were determined. In conclusion, the results showed the ability of thermal lens and interferometric methods to perform measurements very close to the phase transition region. These techniques provide absolute values for the measured physical quantities and are advantageous when low scan rates are required.

Squeezed light for the interferometric detection of high-frequency gravitational waves

Science.gov (United States)

Schnabel, R.; Harms, J.; Strain, K. A.; Danzmann, K.

2004-03-01

The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 106dB/20dB ap 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 × 10-23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity.

Squeezed light for the interferometric detection of high-frequency gravitational waves

International Nuclear Information System (INIS)

Schnabel, R; Harms, J; Strain, K A; Danzmann, K

2004-01-01

The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 10 6dB/20dB ∼ 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 x 10 -23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity

Central Solenoid On-surface Test

CERN Multimedia

Ruber, R

2004-01-01

A full scale on-surface test of the central solenoid has been performed before its final installation in the ATLAS cavern starting in November. The successful integration of the central solenoid into the barrel cryostat, as reported in the March 2004 ATLAS eNews, was hardly finished when testing started. After a six-week period to cool down the LAr calorimeter, the solenoid underwent a similar procedure. Cooling it down to 4.6 Kelvin from room temperature took just over five and a half days. Cold and superconducting, it was time to validate the functionality of the control and safety systems. These systems were largely the same as the systems to be used in the final underground installation, and will be used not only for the solenoid and toroid magnets, but parts of it also for other LHC experiments. This solenoid test was the first occasion to test the system functionality in a real working environment. Several days were spent to fine tune the systems, especially the critical safety system, which turned out...

Wavelet processing and digital interferometric contrast to improve reconstructions from X-ray Gabor holograms.

Science.gov (United States)

Aguilar, Juan C; Misawa, Masaki; Matsuda, Kiyofumi; Suzuki, Yoshio; Takeuchi, Akihisa; Yasumoto, Masato

2018-05-01

In this work, the application of an undecimated wavelet transformation together with digital interferometric contrast to improve the resulting reconstructions in a digital hard X-ray Gabor holographic microscope is shown. Specifically, the starlet transform is used together with digital Zernike contrast. With this contrast, the results show that only a small set of scales from the hologram are, in effect, useful, and it is possible to enhance the details of the reconstruction.

Interferometric investigation methods of plasma spatial characteristics on stellarators and tokamaks in submillimeter region

International Nuclear Information System (INIS)

Berezhnyj, V.L.; Kononenko, V.I.; Epishin, V.A.; Topkov, A.N.

1992-01-01

The review of interferometric methods of plasma investigation in the wave submillimeter range is given. The diagnostic schemes in stellarators and tokamaks designed for experienced thermonuclear reactors and also the perspective ones, which are still out of practice, are shown. The methods of these diagnostics, their physical principles, the main possibilities and restrictions at changes of electron density, magnetic fields (currents) and their spatial distributions are described. 105 refs.; 9 figs.; 2 tables. (author)

Development of Pseudorandom Binary Arrays for Calibration of Surface Profile Metrology Tools

International Nuclear Information System (INIS)

Barber, S.K.; Takacs, P.; Soldate, P.; Anderson, E.H.; Cambie, R.; McKinney, W.R.; Voronov, D.L.; Yashchuk, V.V.

2009-01-01

measured and simulated PSD distributions gives the MTF of the instrument. The applicability of the MTF concept to phase map measurements with optical interferometric microscopes needs to be experimentally verified as the optical tool and algorithms may introduce nonlinear artifacts into the process. In previous work [V. V. Yashchuk et al., Proc. SPIE 6704, 670408 (2007); Valeriy V. Yashchuk et al., Opt. Eng. (Bellingham) 47, 073602 (2008)] the instrumental MTF of a surface profiler was precisely measured using reference test surfaces based on binary pseudorandom (BPR) gratings. Here, the authors present results of fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. BPR sequences are widely used in engineering and communication applications such as global position systems and wireless communication protocols. The ideal BPR pattern has a flat 'white noise' response over the entire range of spatial frequencies of interest. The BPR array used here is based on the uniformly redundant array (URA) prescription [E. E. Fenimore and T. M. Cannon, Appl. Opt. 17, 337 (1978)] initially used for x-ray and gamma ray astronomy applications. The URA's superior imaging capability originates from the fact that its cyclical autocorrelation function very closely approximates a delta function, which produces a flat PSD. Three different size BPR array patterns were fabricated by electron beam lithography and induction coupled plasma etching of silicon. The basic size units were 200, 400, and 600 nm. Two different etch processes were used, CF 4 /Ar and HBr, which resulted in undercut and vertical sidewall profiles, respectively. The 2D BPR arrays were used as standard test surfaces for MTF calibration of the MicroMap(trademark)-570 interferometric microscope using all available objectives. The MicroMap(trademark)-570 interferometric microscope uses incoherent illumination from a tungsten filament source and common path modulated

Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

Energy Technology Data Exchange (ETDEWEB)

Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Sancho-Parramon, J. [Rudjer Boskovic Institute, Bijenicka c. 54, Zagreb 10002 (Croatia); Jover, E.; Bertran, E. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Canillas, A., E-mail: acanillas@ub.ed [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain)

2011-02-28

We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 {mu}m and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

An interferometric complementarity experiment in a bulk nuclear magnetic resonance ensemble

International Nuclear Information System (INIS)

Peng Xinhua; Zhu Xiwen; Fang Ximing; Feng Mang; Liu Maili; Gao Kelin

2003-01-01

We have experimentally demonstrated the interferometric complementarity, which relates the distinguishability D quantifying the amount of which-way (WW) information to the fringe visibility V characterizing the wave feature of a quantum entity, in a bulk ensemble by nuclear magnetic resonance (NMR) techniques. We are primarily concerned about the intermediate cases: partial fringe visibility and incomplete WW information. We propose a quantitative measure of D by an alternative geometric strategy and investigate the relation between D and entanglement. By measuring D and V independently, it turns out that the duality relation D 2 + V 2 = 1 holds for pure quantum states of the markers

Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

International Nuclear Information System (INIS)

Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O.; Sancho-Parramon, J.; Jover, E.; Bertran, E.; Canillas, A.

2011-01-01

We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 μm and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

Advanced Wide-Field Interferometric Microscopy for Nanoparticle Sensing and Characterization

Science.gov (United States)

Avci, Oguzhan

Nanoparticles have a key role in today's biotechnological research owing to the rapid advancement of nanotechnology. While metallic, polymer, and semiconductor based artificial nanoparticles are widely used as labels or targeted drug delivery agents, labeled and label-free detection of natural nanoparticles promise new ways for viral diagnostics and therapeutic applications. The increasing impact of nanoparticles in bio- and nano-technology necessitates the development of advanced tools for their accurate detection and characterization. Optical microscopy techniques have been an essential part of research for visualizing micron-scale particles. However, when it comes to the visualization of individual nano-scale particles, they have shown inadequate success due to the resolution and visibility limitations. Interferometric microscopy techniques have gained significant attention for providing means to overcome the nanoparticle visibility issue that is often the limiting factor in the imaging techniques based solely on the scattered light. In this dissertation, we develop a rigorous physical model to simulate the single nanoparticle optical response in a common-path wide-field interferometric microscopy (WIM) system. While the fundamental elements of the model can be used to analyze nanoparticle response in any generic wide-field imaging systems, we focus on imaging with a layered substrate (common-path interferometer) where specular reflection of illumination provides the reference light for interferometry. A robust physical model is quintessential in realizing the full potential of an optical system, and throughout this dissertation, we make use of it to benchmark our experimental findings, investigate the utility of various optical configurations, reconstruct weakly scattering nanoparticle images, as well as to characterize and discriminate interferometric nanoparticle responses. This study investigates the integration of advanced optical schemes in WIM with two

Spectral and interferometric observation of four emission nebulas

International Nuclear Information System (INIS)

Lozinskaya, T.A.; Klement'eva, A.Yu.; Zhukov, G.V.; Shenavrin, V.I.

1975-01-01

Results of spectrophotometric and interferometric observations of four emission nebulae are presented; electron temperature Te and electron density Ne are estimated; mean beam velocities and parameters of the internal motion in the nebylae are determined. The following objects have been investigated: 1) a bright compact nebulae of unknown nature 2.5 in size which is identified with the non-thermal radiosource G6.4-0.5 in the region W28; 2) nebulae RCW171 5' in size which is identified with the radiosource G23.1+0.6; 3) the nebulae Simeiz 34/Sharpless 261/d 1950 =6sup(h)05sup(m), sigma 1950 =+15 deg 49'; its diameter is approximately 30 an extensive complex of bright emission fibres in the nebulae Swan, which are partially projected into a possible remainder of the outburst of a supernova W63; L 1950 =20sup(h)17sup(m); S 1950 =45 deg 30' its diameter is approximately 1 deg 5

Off-line testing of multifunctional surfaces for metal forming applications

DEFF Research Database (Denmark)

Godi, A.; Grønbæk, J.; De Chiffre, L.

2015-01-01

In this paper, Bending-Under-Tension, an off-line test method simulating deep-drawing, is chosen for investigating the effectiveness of multifunctional (MUFU) surfaces in metal forming operations. Four different MUFU surfaces, characterized by a plateau bearing area and grooves for lubricant...... retention, are manufactured, together with two polished references. During the tests, surface texture is the only variable. The results show how MUFU surfaces perform better than the polished references, which produce severe galling, while MUFU surfaces with low bearing area display no clear evidence...... of galling. Metal-to-metal contact occurs anyway, but the strip material is pulverized and deposited onto the tool instead of cold-welding to it. The pockets create a discontinuity on the texture hindering pick-up propagation....

Segmented Aperture Interferometric Nulling Testbed (SAINT) II: component systems update

Science.gov (United States)

Hicks, Brian A.; Bolcar, Matthew R.; Helmbrecht, Michael A.; Petrone, Peter; Burke, Elliot; Corsetti, James; Dillon, Thomas; Lea, Andrew; Pellicori, Samuel; Sheets, Teresa; Shiri, Ron; Agolli, Jack; DeVries, John; Eberhardt, Andrew; McCabe, Tyler

2017-09-01

This work presents updates to the coronagraph and telescope components of the Segmented Aperture Interferometric Nulling Testbed (SAINT). The project pairs an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC) towards demonstrating capabilities for the future space observatories needed to directly detect and characterize a significant sample of Earth-sized worlds around nearby stars in the quest for identifying those which may be habitable and possibly harbor life. Efforts to improve the VNC wavefront control optics and mechanisms towards repeating narrowband results are described. A narrative is provided for the design of new optical components aimed at enabling broadband performance. Initial work with the hardware and software interface for controlling the segmented telescope mirror is also presented.

Interferometric system with tracking refractometry capability in the measuring axis

International Nuclear Information System (INIS)

Lazar, J; Holá, M; Číp, O; Hrabina, J; Oulehla, J

2013-01-01

We present a combined interferometric arrangement designed for measurement of one-axis displacement over a specified measuring range with mechanical referencing. This concept allows simultaneous measurement of the carriage position from both sides together with monitoring of the overall range. This can be used in configuration with in-line monitoring of the fluctuations of the refractive index-–tracking refractometry. Similarly, the wavelength of the laser source can be stabilized over the measuring range, effectively compensating for the refractive index changes. Otherwise, monitoring of length of the measuring range can give information about the thermal dilatation effects of frame of the whole measuring setup. This technique can find its way into high-precision positioning systems in nanometrology. (technical design note)

Parametric estimation of time varying baselines in airborne interferometric SAR

DEFF Research Database (Denmark)

Mohr, Johan Jacob; Madsen, Søren Nørvang

1996-01-01

A method for estimation of time varying spatial baselines in airborne interferometric synthetic aperture radar (SAR) is described. The range and azimuth distortions between two images acquired with a non-linear baseline are derived. A parametric model of the baseline is then, in a least square...... sense, estimated from image shifts obtained by cross correlation of numerous small patches throughout the image. The method has been applied to airborne EMISAR imagery from the 1995 campaign over the Storstrommen Glacier in North East Greenland conducted by the Danish Center for Remote Sensing. This has...... reduced the baseline uncertainties from several meters to the centimeter level in a 36 km scene. Though developed for airborne SAR the method can easily be adopted to satellite data...

Cost-effective optical fiber pressure sensor based on intrinsic Fabry-Perot interferometric micro-cavities

Science.gov (United States)

Domingues, M. Fátima; Rodriguez, Camilo A.; Martins, Joana; Tavares, Cátia; Marques, Carlos; Alberto, Nélia; André, Paulo; Antunes, Paulo

2018-05-01

In this work, a cost-effective procedure to manufacture optical fiber pressure sensors is presented. This has a high relevance for integration in robotic exoskeletons or for gait plantar pressure monitoring within the physical rehabilitation scenarios, among other applications. The sensing elements are based on Fabry-Perot interferometric (FPI) micro-cavities, created from the recycling of optical fibers previously destroyed by the catastrophic fuse effect. To produce the pressure sensors, the fiber containing the FPI micro-cavities was embedded in an epoxy resin cylinder used as pressure transducer and responsible to transfer the pressure applied on its surface to the optical fiber containing the FPI micro-cavity. Before the embedding process, some FPI sensors were also characterized to strain variations. After that, the effect of the encapsulation of the FPI structure into the resin was assessed, from which a slight decrease on the FPI interferogram fringes visibility was verified, indicating a small increase in the micro-cavity length. Up on the sensors characterization, a linear dependence of the wavelength shift with the induced pressure was obtained, which leads to a maximum sensitivity of 59.39 ± 1.7 pm/kPa. Moreover, direct dependence of the pressure sensitivity with the micro-cavity volume and length was found.

Multi-path interferometric Josephson directional amplifier for qubit readout

Science.gov (United States)

Abdo, Baleegh; Bronn, Nicholas T.; Jinka, Oblesh; Olivadese, Salvatore; Brink, Markus; Chow, Jerry M.

2018-04-01

We realize and characterize a quantum-limited, directional Josephson amplifier suitable for qubit readout. The device consists of two nondegenerate, three-wave-mixing amplifiers that are coupled together in an interferometric scheme, embedded in a printed circuit board. Nonreciprocity is generated by applying a phase gradient between the same-frequency pumps feeding the device, which plays the role of the magnetic field in a Faraday medium. Directional amplification and reflection-gain elimination are induced via wave interference between multiple paths in the system. We measure and discuss the main figures of merit of the device and show that the experimental results are in good agreement with theory. An improved version of this directional amplifier is expected to eliminate the need for bulky, off-chip isolation stages that generally separate quantum systems and preamplifiers in high-fidelity, quantum-nondemolition measurement setups.

Rotationally Adaptive Flight Test Surface

Science.gov (United States)

Barrett, Ron

1999-01-01

Research on a new design of flutter exciter vane using adaptive materials was conducted. This novel design is based on all-moving aerodynamic surface technology and consists of a structurally stiff main spar, a series of piezoelectric actuator elements and an aerodynamic shell which is pivoted around the main spar. The work was built upon the current missile-type all-moving surface designs and change them so they are better suited for flutter excitation through the transonic flight regime. The first portion of research will be centered on aerodynamic and structural modeling of the system. USAF DatCom and vortex lattice codes was used to capture the fundamental aerodynamics of the vane. Finite element codes and laminated plate theory and virtual work analyses will be used to structurally model the aerodynamic vane and wing tip. Following the basic modeling, a flutter test vane was designed. Each component within the structure was designed to meet the design loads. After the design loads are met, then the deflections will be maximized and the internal structure will be laid out. In addition to the structure, a basic electrical control network will be designed which will be capable of driving a scaled exciter vane. The third and final stage of main investigation involved the fabrication of a 1/4 scale vane. This scaled vane was used to verify kinematics and structural mechanics theories on all-moving actuation. Following assembly, a series of bench tests was conducted to determine frequency response, electrical characteristics, mechanical and kinematic properties. Test results indicate peak-to-peak deflections of 1.1 deg with a corner frequency of just over 130 Hz.

ACIGA's high optical power test facility

International Nuclear Information System (INIS)

Ju, L; Aoun, M; Barriga, P

2004-01-01

Advanced laser interferometer detectors utilizing more than 100 W of laser power and with ∼10 6 W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties

Differential Radiometers Using Fabry-Perot Interferometric Technique for Remote Sensing of Greenhouse Gases

Science.gov (United States)

Georgieva, Elena M.; Heaps,William S.; Wilson, Emily L.

2007-01-01

A new type of remote sensing radiometer based upon the Fabry-Perot interferometric technique has been developed at NASA's Goddard Space Flight Center and tested from both ground and aircraft platform. The sensor uses direct or reflected sunlight and has channels for measuring column concentration of carbon dioxide at 1570 nm, oxygen lines sensitive to pressure and temperature at 762 and 768 nm, and water vapor (940 nm). A solid Fabry-Perot etalon is used as a tunable narrow bandpass filter to restrict the measurement to the gas of interest's absorption bands. By adjusting the temperature of the etalon, which changes the index of refraction of its material, the transmission fringes can be brought into nearly exact correspondence with absorption lines of the particular species. With this alignment between absorption lines and fringes, changes in the amount of a species in the atmosphere strongly affect the amount of light transmitted by the etalon and can be related to gas concentration. The technique is applicable to different chemical species. We have performed simulations and instrument design studies for CH4, "Cot isotope, and CO detection. Index Terms- Absorbing media, Atmospheric measurements, Fabry-Perot interferometers, Optical interferometry, Remote sensing.

Determination of the Basic Friction Angle of Rock Surfaces by Tilt Tests

Science.gov (United States)

Jang, Hyun-Sic; Zhang, Qing-Zhao; Kang, Seong-Seung; Jang, Bo-An

2018-04-01

Samples of Hwangdeung granite from Korea and Berea sandstone from USA, both containing sliding planes, were prepared by saw-cutting or polishing using either #100 or #600 grinding powders. Their basic friction angles were measured by direct shear testing, triaxial compression testing, and tilt testing. The direct shear tests and triaxial compression tests on the saw-cut, #100, and #600 surfaces indicated that the most reliable results were obtained from the #100 surface: basic friction angle of 29.4° for granite and 34.1° for sandstone. To examine the effect of surface conditions on the friction angle in tilt tests, the sliding angles were measured 50 times with two surface conditions (surfaces cleaned and not cleaned after each measurement). The initial sliding angles were high regardless of rock type and surface conditions and decreased exponentially as measurements continued. The characteristics of the sliding angles, differences between tilt tests, and dispersion between measurements in each test indicated that #100 surface produced the most reliable basic friction angle measurement. Without cleaning the surfaces, the average angles for granite (32 measurements) and sandstone (23 measurements) were similar to the basic friction angle. When 20-50 measurements without cleaning were averaged, the basic friction angle was within ± 2° for granite and ± 3° for sandstone. Sliding angles using five different tilting speeds were measured but the average was similar, indicating that tilting speed (between 0.2° and 1.6°/s) has little effect on the sliding angle. Sliding angles using four different sample sizes were measured with the best results obtained for samples larger than 8 × 8 cm.

Characterization of the structure of the coating of multilayers using AFM and Interferometric Microscopy

International Nuclear Information System (INIS)

Jerez A, Martha I; Lara O, Laura; Morantes M, Luz D; Plata G, Arturo; Torres, Yezid; Tsygankov, Petr

2011-01-01

Ti / TiN films were deposited on H13 steel and silicon substrates with different deposition voltage, by means of the cathodic arc evaporation (CAE) technique, this process was carried out by nanolayers deposition, requiring a detailed survey on growth films, for the properties characterization such as grain size, thickness and roughness of the film was used the atomic force microscopy (AFM) techniques and Interferometric Microscopy. Obtaining a the films growth when varying the deposition voltage.

AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors

Energy Technology Data Exchange (ETDEWEB)

Barriga, P; Blair, D G; Coward, D; Davidson, J; Dumas, J-C; Howell, E; Ju, L; Wen, L; Zhao, C [School of Physics, The University of Western Australia, Crawley, WA 6009 (Australia); McClelland, D E; Scott, S M; Slagmolen, B J J; Inta, R [Department of Physics, Faculty of Science, Australian National University, Canberra, ACT 0200 (Australia); Munch, J; Ottaway, D J; Veitch, P; Hosken, D [Department of Physics, University of Adelaide, Adelaide, SA 5005 (Australia); Melatos, A; Chung, C; Sammut, L, E-mail: pbarriga@cyllene.uwa.edu.a [School of Physics University of Melbourne, Parkville, Vic 3010 (Australia)

2010-04-21

This paper describes the proposed AIGO detector for the worldwide array of interferometric gravitational wave detectors. The first part of the paper summarizes the benefits that AIGO provides to the worldwide array of detectors. The second part gives a technical description of the detector, which will follow closely the Advanced LIGO design. Possible technical variations in the design are discussed.

AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors

OpenAIRE

Barriga, P.; Blair, D.; Coward, D.; Davidson, J.; Dumas, J.; Howell, E.; Ju, L.; Wen, L.; Zhao, C.; McClelland, D.; Scott, S.; Slagmolen, B.; Inta, R.; Munch, J.; Ottaway, D.

2010-01-01

This paper describes the proposed AIGO detector for the worldwide array of interferometric gravitational wave detectors. The first part of the paper summarizes the benefits that AIGO provides to the worldwide array of detectors. The second part gives a technical description of the detector, which will follow closely the Advanced LIGO design. Possible technical variations in the design are discussed.

Interferometric and nonlinear-optical spectral-imaging techniques for outer space and live cells

Science.gov (United States)

Itoh, Kazuyoshi

2015-12-01

Multidimensional signals such as the spectral images allow us to have deeper insights into the natures of objects. In this paper the spectral imaging techniques that are based on optical interferometry and nonlinear optics are presented. The interferometric imaging technique is based on the unified theory of Van Cittert-Zernike and Wiener-Khintchine theorems and allows us to retrieve a spectral image of an object in the far zone from the 3D spatial coherence function. The retrieval principle is explained using a very simple object. The promising applications to space interferometers for astronomy that are currently in progress will also be briefly touched on. An interesting extension of interferometric spectral imaging is a 3D and spectral imaging technique that records 4D information of objects where the 3D and spectral information is retrieved from the cross-spectral density function of optical field. The 3D imaging is realized via the numerical inverse propagation of the cross-spectral density. A few techniques suggested recently are introduced. The nonlinear optical technique that utilizes stimulated Raman scattering (SRS) for spectral imaging of biomedical targets is presented lastly. The strong signals of SRS permit us to get vibrational information of molecules in the live cell or tissue in real time. The vibrational information of unstained or unlabeled molecules is crucial especially for medical applications. The 3D information due to the optical nonlinearity is also the attractive feature of SRS spectral microscopy.

Applicability of interferometric SAR technology to ground movement and pipeline monitoring

Science.gov (United States)

Grivas, Dimitri A.; Bhagvati, Chakravarthy; Schultz, B. C.; Trigg, Alan; Rizkalla, Moness

1998-03-01

This paper summarizes the findings of a cooperative effort between NOVA Gas Transmission Ltd. (NGTL), the Italian Natural Gas Transmission Company (SNAM), and Arista International, Inc., to determine whether current remote sensing technologies can be utilized to monitor small-scale ground movements over vast geographical areas. This topic is of interest due to the potential for small ground movements to cause strain accumulation in buried pipeline facilities. Ground movements are difficult to monitor continuously, but their cumulative effect over time can have a significant impact on the safety of buried pipelines. Interferometric synthetic aperture radar (InSAR or SARI) is identified as the most promising technique of those considered. InSAR analysis involves combining multiple images from consecutive passes of a radar imaging platform. The resulting composite image can detect changes as small as 2.5 to 5.0 centimeters (based on current analysis methods and radar satellite data of 5 centimeter wavelength). Research currently in progress shows potential for measuring ground movements as small as a few millimeters. Data needed for InSAR analysis is currently commercially available from four satellites, and additional satellites are planned for launch in the near future. A major conclusion of the present study is that InSAR technology is potentially useful for pipeline integrity monitoring. A pilot project is planned to test operational issues.

Three-dimensional surface deformation derived from airborne interferometric UAVSAR: Application to the Slumgullion Landslide

Science.gov (United States)

Delbridge, Brent G.; Burgmann, Roland; Fielding, Eric; Hensley, Scott; Schulz, William

2016-01-01

In order to provide surface geodetic measurements with “landslide-wide” spatial coverage, we develop and validate a method for the characterization of 3-D surface deformation using the unique capabilities of the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne repeat-pass radar interferometry system. We apply our method at the well-studied Slumgullion Landslide, which is 3.9 km long and moves persistently at rates up to ∼2 cm/day. A comparison with concurrent GPS measurements validates this method and shows that it provides reliable and accurate 3-D surface deformation measurements. The UAVSAR-derived vector velocity field measurements accurately capture the sharp boundaries defining previously identified kinematic units and geomorphic domains within the landslide. We acquired data across the landslide during spring and summer and identify that the landslide moves more slowly during summer except at its head, presumably in response to spatiotemporal variations in snowmelt infiltration. In order to constrain the mechanics controlling landslide motion from surface velocity measurements, we present an inversion framework for the extraction of slide thickness and basal geometry from dense 3-D surface velocity fields. We find that the average depth of the Slumgullion Landslide is 7.5 m, several meters less than previous depth estimates. We show that by considering a viscoplastic rheology, we can derive tighter theoretical bounds on the rheological parameter relating mean horizontal flow rate to surface velocity. Using inclinometer data for slow-moving, clay-rich landslides across the globe, we find a consistent value for the rheological parameter of 0.85 ± 0.08.

Test Operation Procedure (TOP) 01-1-010A Vehicle Test Course Severity (Surface Roughness)

Science.gov (United States)

2017-12-12

Increases in roughness may signify the need to change course maintenance patterns. For example, secondary gravel roads at YTC go through a cycle of...CSTE-DTC-AT-AD) U.S. Army Aberdeen Test Center 400 Colleran Road Aberdeen Proving Ground, MD 21005-5059 8. PERFORMING ORGANIZATION REPORT...test courses at ATEC Test Centers. 15. SUBJECT TERMS Automotive test course Roughness of roads Wave number spectrum Test course surface roughness

Anomalous optical surface absorption in nominally pure silicon samples at 1550 nm

Science.gov (United States)

Bell, Angus S.; Steinlechner, Jessica; Martin, Iain W.; Craig, Kieran; Cunningham, William; Rowan, Sheila; Hough, Jim; Schnabel, Roman; Khalaidovski, Alexander

2017-10-01

The announcement of the direct detection of gravitational waves (GW) by the LIGO and Virgo collaboration in February 2016 has removed any uncertainty around the possibility of GW astronomy. It has demonstrated that future detectors with sensitivities ten times greater than the Advanced LIGO detectors would see thousands of events per year. Many proposals for such future interferometric GW detectors assume the use of silicon test masses. Silicon has low mechanical loss at low temperatures, which leads to low displacement noise for a suspended interferometer mirror. In addition to the low mechanical loss, it is a requirement that the test masses have a low optical loss. Measurements at 1550 nm have indicated that material with a low enough bulk absorption is available; however there have been suggestions that this low absorption material has a surface absorption of  >100 ppm which could preclude its use in future cryogenic detectors. We show in this paper that this surface loss is not intrinsic but is likely to be a result of particular polishing techniques and can be removed or avoided by the correct polishing procedure. This is an important step towards high gravitational wave detection rates in silicon based instruments.

Anomalous optical surface absorption in nominally pure silicon samples at 1550 nm

International Nuclear Information System (INIS)

Bell, Angus S; Steinlechner, Jessica; Martin, Iain W; Craig, Kieran; Cunningham, William; Rowan, Sheila; Hough, Jim; Schnabel, Roman; Khalaidovski, Alexander

2017-01-01

The announcement of the direct detection of gravitational waves (GW) by the LIGO and Virgo collaboration in February 2016 has removed any uncertainty around the possibility of GW astronomy. It has demonstrated that future detectors with sensitivities ten times greater than the Advanced LIGO detectors would see thousands of events per year. Many proposals for such future interferometric GW detectors assume the use of silicon test masses. Silicon has low mechanical loss at low temperatures, which leads to low displacement noise for a suspended interferometer mirror. In addition to the low mechanical loss, it is a requirement that the test masses have a low optical loss. Measurements at 1550 nm have indicated that material with a low enough bulk absorption is available; however there have been suggestions that this low absorption material has a surface absorption of  >100 ppm which could preclude its use in future cryogenic detectors. We show in this paper that this surface loss is not intrinsic but is likely to be a result of particular polishing techniques and can be removed or avoided by the correct polishing procedure. This is an important step towards high gravitational wave detection rates in silicon based instruments. (paper)

INTERFEROMETRIC EVIDENCE FOR RESOLVED WARM DUST IN THE DQ TAU SYSTEM

International Nuclear Information System (INIS)

Boden, Andrew F.; Sargent, Anneila I.; Carpenter, John M.; Akeson, Rachel L.; Ciardi, David R.; Bary, Jeffrey S.; Skrutskie, Michael F.

2009-01-01

We report on near-infrared (IR) interferometric observations of the double-lined pre-main sequence binary system DQ Tau. We model these data with a visual orbit for DQ Tau supported by the spectroscopic orbit and analysis of Mathieu et al. Further, DQ Tau exhibits significant near-IR excess; modeling our data requires inclusion of near-IR light from an 'excess' source. Remarkably, the excess source is resolved in our data, similar in scale to the binary itself (∼0.2 AU at apastron), rather than the larger circumbinary disk (∼0.4 AU radius). Our observations support the Mathieu et al. and Carr et al. inference of significant warm material near the DQ Tau binary.

Distributed fiber optic interferometric geophone system based on draw tower gratings

Science.gov (United States)

Xu, Ruquan; Guo, Huiyong; Liang, Lei

2017-09-01

A distributed fiber optic interferometric geophone array based on draw tower grating (DTG) array is proposed. The DTG geophone array is made by the DTG array fabricated based on a near-contact exposure through a phase mask during the fiber drawing process. A distributed sensing system with 96 identical DTGs in an equal separation of 20 m and an unbalanced Michelson interferometer for vibration measurement has been experimentally validated compared with a moving-coil geophone. The experimental results indicate that the sensing system can linearly demodulate the phase shift. Compared with the moving coil geophone, the fiber optic sensing system based on DTG has higher signal-to-noise ratio at low frequency.

Ortho-Babinet polarization-interrogating filter: an interferometric approach to polarization measurement.

Science.gov (United States)

Van Delden, Jay S

2003-07-15

A novel, interferometric, polarization-interrogating filter assembly and method for the simultaneous measurement of all four Stokes parameters across a partially polarized irradiance image in a no-moving-parts, instantaneous, highly sensitive manner is described. In the reported embodiment of the filter, two spatially varying linear retarders and a linear polarizer comprise an ortho-Babinet, polarization-interrogating (OBPI) filter. The OBPI filter uniquely encodes the incident ensemble of electromagnetic wave fronts comprising a partially polarized irradiance image in a controlled, deterministic, spatially varying manner to map the complete state of polarization across the image to local variations in a superposed interference pattern. Experimental interferograms are reported along with a numerical simulation of the method.

Tests of stellar model atmospheres by optical interferometry. VLTI/VINCI limb-darkening measurements of the M4 giant ψ Phe

Science.gov (United States)

Wittkowski, M.; Aufdenberg, J. P.; Kervella, P.

2004-01-01

We present K-band interferometric measurements of the limb-darkened (LD) intensity profile of the M 4 giant star ψ Phoenicis obtained with the Very Large Telescope Interferometer (VLTI) and its commissioning instrument VINCI. High-precision squared visibility amplitudes in the second lobe of the visibility function were obtained employing two 8.2 m Unit Telescopes (UTs). This took place one month after light from UTs was first combined for interferometric fringes. In addition, we sampled the visibility function at small spatial frequencies using the 40 cm test siderostats. Our measurement constrains the diameter of the star as well as its center-to-limb intensity variation (CLV). We construct a spherical hydrostatic PHOENIX model atmosphere based on spectrophotometric data from the literature and compare its CLV prediction with our interferometric measurement. We compare as well CLV predictions by plane-parallel hydrostatic PHOENIX, ATLAS 9, and ATLAS 12 models. We find that the Rosseland angular diameter as predicted by comparison of the spherical PHOENIX model with spectrophotometry is in good agreement with our interferometric diameter measurement. The shape of our measured visibility function in the second lobe is consistent with all considered PHOENIX and ATLAS model predictions, and is significantly different to uniform disk (UD) and fully darkened disk (FDD) models. We derive high-precision fundamental parameters for ψ Phe, namely a Rosseland angular diameter of 8.13 ± 0.2 mas, with the Hipparcos parallax corresponding to a Rosseland linear radius R of 86 ± 3 R⊙, and an effective temperature of 3550 ± 50 K, with R corresponding to a luminosity of \\log L/L⊙=3.02 ± 0.06. Together with evolutionary models, these values are consistent with a mass of 1.3 ± 0.2 M⊙, and a surface gravity of \\log g = 0.68 ± 0.11. Based on public data released from the European Southern Observatory VLTI obtained from the ESO/ST-ECF Science Archive Facility. The VLTI

The Segmented Aperture Interferometric Nulling Testbed (SAINT) I: overview and air-side system description

Science.gov (United States)

Hicks, Brian A.; Lyon, Richard G.; Petrone, Peter; Ballard, Marlin; Bolcar, Matthew R.; Bolognese, Jeff; Clampin, Mark; Dogoda, Peter; Dworzanski, Daniel; Helmbrecht, Michael A.; Koca, Corina; Shiri, Ron

2016-07-01

This work presents an overview of the Segmented Aperture Interferometric Nulling Testbed (SAINT), a project that will pair an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC). SAINT will incorporate the VNC's demonstrated wavefront sensing and control system to refine and quantify end-to-end high-contrast starlight suppression performance. This pathfinder testbed will be used as a tool to study and refine approaches to mitigating instabilities and complex diffraction expected from future large segmented aperture telescopes.

Interferometric detectors of gravitational waves on Earth: the next generations

Energy Technology Data Exchange (ETDEWEB)

Losurdo, G [INFN Firenze - Via G.Sansone 1, 50019 - Sesto F., Firenze (Italy)], E-mail: losurdo@fi.infn.it

2008-05-15

First generation long-baseline interferometric detectors of gravitational waves are now taking data. A first detection might be possible with these instruments, but more sensitive detectors will be needed to start the field of gravitational wave astronomy. Second generation interferometers will improve the sensitivity by a factor ten, allowing to explore a universe volume 1000 times larger. The technology is almost ready and the construction will start at the beginning of the next decade. The community of the physicists involved in the field has also started to make plans for third generation detectors, for which a long term technology development program will be required. The plans for the upgrades of the existing detectors and the scenario for the evolution of the field will be reviewed in this paper.

A Comparison of Acoustic Field Measurement by a Microphone and by an Optical Interferometric Probe

Directory of Open Access Journals (Sweden)

R. Bálek

2002-01-01

Full Text Available The objective of this work is to show that our optical method for measuring acoustic pressure is in some way superior to measurement using a microphone. Measurement of the integral acoustic pressure in the air by a laser interferometric probe is compared with measurement using a microphone. We determined the particular harmonic components in the acoustic field in the case of relatively high acoustic power in the ultrasonic frequency range.

A New Rig for Testing Textured Surfaces in Pure Sliding Conditions

DEFF Research Database (Denmark)

Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

2013-01-01

machineries are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Preliminary tests are carried out involving a multifunctional and a fine......Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, as demonstrated by the development and spread of plateau-honed surface...... for cylinder liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper, a new test rig simulating pure sliding conditions is presented, dubbed axial sliding test. It presents four major components: a rod...

Design and laboratory validation of a structural element instrumented with multiplexed interferometric fiber optic sensors

Science.gov (United States)

Zonta, Daniele; Pozzi, Matteo; Wu, Huayong; Inaudi, Daniele

2008-03-01

This paper introduces a concept of smart structural elements for the real-time condition monitoring of bridges. These are prefabricated reinforced concrete elements embedding a permanent sensing system and capable of self-diagnosis when in operation. The real-time assessment is automatically controlled by a numerical algorithm founded on Bayesian logic: the method assigns a probability to each possible damage scenario, and estimates the statistical distribution of the damage parameters involved (such as location and extent). To verify the effectiveness of the technology, we produced and tested in the laboratory a reduced-scale smart beam prototype. The specimen is 3.8 m long and has cross-section 0.3 by 0.5m, and has been prestressed using a Dywidag bar, in such a way as to control the preload level. The sensor system includes a multiplexed version of SOFO interferometric sensors mounted on a composite bar, along with a number of traditional metal-foil strain gauges. The method allowed clear recognition of increasing fault states, simulated on the beam by gradually reducing the prestress level.

Modeling and design of a spiral-shaped Mach-Zehnder interferometric sensor for refractive index sensing of watery solutions

NARCIS (Netherlands)

Hoekman, M.; Dijkstra, Marcel; Dijkstra, Mindert; Hoekstra, Hugo

2006-01-01

The modeling and design of a spiral-shaped Mach-Zehnder Interferometric sensor (sMZI sensor) for refractive index sensing of watery solutions is presented. The goal of the running project is to realise a multi-sensing array by placing multiple sMZIs in series to form a sensing branch, and to place

Atomic Gravitational Wave Interferometric Sensors (AGIS) in Space

Science.gov (United States)

Sugarbaker, Alex; Hogan, Jason; Johnson, David; Dickerson, Susannah; Kovachy, Tim; Chiow, Sheng-Wey; Kasevich, Mark

2012-06-01

Atom interferometers have the potential to make sensitive gravitational wave detectors, which would reinforce our fundamental understanding of gravity and provide a new means of observing the universe. We focus here on the AGIS-LEO proposal [1]. Gravitational waves can be observed by comparing a pair of atom interferometers separated over an extended baseline. The mission would offer a strain sensitivity that would provide access to a rich scientific region with substantial discovery potential. This band is not currently addressed with the LIGO or LISA instruments. We analyze systematic backgrounds that are relevant to the mission and discuss how they can be mitigated at the required levels. Some of these effects do not appear to have been considered previously in the context of atom interferometry, and we therefore expect that our analysis will be broadly relevant to atom interferometric precision measurements. Many of the techniques relevant to an AGIS mission can be investigated in the Stanford 10-m drop tower.[4pt] [1] J.M. Hogan, et al., Gen. Rel. Grav. 43, 1953-2009 (2011).

a Research on Monitoring Surface Deformation and Relationships with Surface Parameters in Qinghai Tibetan Plateau Permafrost

Science.gov (United States)

Mi, S. J.; Li, Y. T.; Wang, F.; Li, L.; Ge, Y.; Luo, L.; Zhang, C. L.; Chen, J. B.

2017-09-01

The Qinghai Tibetan Plateau permafrost has been the largest permafrost region in middle-low latitude in the world for its high altitude. For the large area permafrost, especially surface deformation brought by it, have serious influence on the road engineering, road maintaining and regional economic development. Consequently, it is essential to monitor the surface deformation and study factors that influent it. We monitored an area named Wudaoliang from July 25, 2015 to June 1, 2016 and 15 Sentinel images were obtained during this time. The area we chose is about 35 kilometers long and 2 kilometers wide, and the national road 109 of China passes through the area. The traditional PS-INSAR (Persistent Scatterer Interferometric Synthetic Aperture Radar) method is not suitable because less historical images in the research area and leading to the number of PS (Persistent Scatterer) points is not enough to obtain accurate deformation results. Therefore, in this paper, we used another method which named QUASI-PSInSAR (QUASI Persistent Scatterer Interferometric Synthetic Aperture Radar) to acquire deformation for it has the advantage to weaken or eliminate the effects of spatial and temporal correlation, which has proved by other scholar. After processing 15 images in the SARproz software, we got the conclusions that, 1) the biggest deformation velocity in the whole area was about 127.9mm/year and about 109.3 mm/year in the road; 2) apparent deformation which have surface deformation more than 30mm/year was about 1.7Km in the road. Meanwhile, soil moisture(SM), Land surface temperature (LST) and surface water(SW), which are primary parameters of the land surface over the same time were reversed by using Sentinel data, Landsat data and ZY-3 data, respectively. After analyzing SM, LST , SW and deformation, we obtained that wet areas which had bigger SM, lower LST and more SW, had greater percentage of severe deformation than arid areas; besides, deformation pattern were

Aspheric surface testing by irradiance transport equation

Science.gov (United States)

Shomali, Ramin; Darudi, Ahmad; Nasiri, Sadollah; Asgharsharghi Bonab, Armir

2010-10-01

In this paper a method for aspheric surface testing is presented. The method is based on solving the Irradiance Transport Equation (ITE).The accuracy of ITE normally depends on the amount of the pick to valley of the phase distribution. This subject is investigated by a simulation procedure.

In situ studies of the kinetics of surface topography development during ion irradiation

International Nuclear Information System (INIS)

Levinskas, R.; Pranevicius, L.

1996-01-01

Studies of the mechanical properties of the materials affected by 25-200 keV H + , He + , Ne + and Ar + ion irradiation in the range of fluences up to 2 · 10 17 cm -2 based on the analysis of acoustic emission signals, kinetics of the surface deformations measured by laser interferometric technique and the variations of the surface acoustic waves propagation velocity are conducted. The acoustic emissions source mechanisms under various ion irradiation conditions are discussed and relative contribution various possible mechanism are indicated. The correlation of experimental results obtained by different methods of analysis is done. (author). 11 refs, 5 figs

Field measurement of albedo for limited extent test surfaces

Energy Technology Data Exchange (ETDEWEB)

Sailor, David J. [Portland State University, Department of Mechanical and Materials Engineering, P.O. Box 751-ME, Portland, OR 97207 (United States); Resh, Kyle; Segura, Del [Tulane University, Department of Mechanical Engineering, 400 Lindy Boggs Center, New Orleans, LA 70118 (United States)

2006-05-15

A new method is introduced for field measurement of surface albedo. This method consists of the use of a cylindrical shade ring made of opaque fabric with a known (low) albedo placed over a test surface. The albedo measurement is accomplished using two small pyranometers situated so that the downward-facing pyranometer receives radiation only from the test surface and the shade ring. The upward-facing pyranometer simultaneously records the incoming solar radiation. The radiation received by the downward-facing pyramometer is a combination of reflected radiation from shaded and unshaded portions of these two surfaces, requiring detailed accounting of the resulting view factor geometries. The method presented here improves upon past approaches by allowing for smaller sample sizes, minimizing errors associated with reflective properties of the surroundings, and allowing for accurate measurements even under partially cloudy skies. In addition to these methodological improvements we introduce an approach for estimating the uncertainty in the resulting albedo measurements. Results from field measurements are presented to validate the measurement protocol, and to compare its accuracy with the accuracy of a published standard. (author)

Mach-Zehnder interferometric photonic crystal fiber for low acoustic frequency detections

Energy Technology Data Exchange (ETDEWEB)

Pawar, Dnyandeo; Rao, Ch. N.; Kale, S. N., E-mail: sangeetakale2004@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411 025, Maharashtra (India); Choubey, Ravi Kant [Department of Applied Physics, Amity Institute of Applied Sciences, Amity University, Noida 201 313 (India)

2016-01-25

Low frequency under-water acoustic signal detections are challenging, especially for marine applications. A Mach-Zehnder interferometric hydrophone is demonstrated using polarization-maintaining photonic-crystal-fiber (PM-PCF), spliced between two single-mode-fibers, operated at 1550 nm source. These data are compared with standard hydrophone, single-mode and multimode fiber. The PM-PCF sensor shows the highest response with a power shift (2.32 dBm) and a wavelength shift (392.8 pm) at 200 Hz. High birefringence values and the effect of the imparted acoustic pressure on this fiber, introducing the difference between the fast and slow axis changes, owing to the phase change in the propagation waves, demonstrate the strain-optic properties of the sensor.

Method and Apparatus for Creating a Topography at a Surface

Science.gov (United States)

Adams, David P.; Sinclair, Michael B.; Mayer, Thomas M.; Vasile, Michael J.; Sweatt, William C.

2008-11-11

Methods and apparatus whereby an optical interferometer is utilized to monitor and provide feedback control to an integrated energetic particle column, to create desired topographies, including the depth, shape and/or roughness of features, at a surface of a specimen. Energetic particle columns can direct energetic species including, ions, photons and/or neutral particles to a surface to create features having in-plane dimensions on the order of 1 micron, and a height or depth on the order of 1 nanometer. Energetic processes can include subtractive processes such as sputtering, ablation, focused ion beam milling and, additive processes, such as energetic beam induced chemical vapor deposition. The integration of interferometric methods with processing by energetic species offers the ability to create desired topographies at surfaces, including planar and curved shapes.

Standard practice for fracture testing with surface-crack tension specimens

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

1.1 This practice covers the design, preparation, and testing of surface-crack tension (SCT) specimens. It relates specifically to testing under continuously increasing force and excludes cyclic and sustained loadings. The quantity determined is the residual strength of a specimen having a semielliptical or circular-segment fatigue crack in one surface. This value depends on the crack dimensions and the specimen thickness as well as the characteristics of the material. 1.2 Metallic materials that can be tested are not limited by strength, thickness, or toughness. However, tests of thick specimens of tough materials may require a tension test machine of extremely high capacity. The applicability of this practice to nonmetallic materials has not been determined. 1.3 This practice is limited to specimens having a uniform rectangular cross section in the test section. The test section width and length must be large with respect to the crack length. Crack depth and length should be chosen to suit the ultimate pu...

FIRST L-BAND INTERFEROMETRIC OBSERVATIONS OF A YOUNG STELLAR OBJECT: PROBING THE CIRCUMSTELLAR ENVIRONMENT OF MWC 419

International Nuclear Information System (INIS)

Ragland, S.; Armandroff, T.; Wizinowich, P. L.; Akeson, R. L.; Millan-Gabet, R.; Colavita, M. M.; Traub, W. A.; Vasisht, G.; Danchi, W. C.; Hillenbrand, L. A.; Ridgway, S. T.

2009-01-01

We present spatially resolved K- and L-band spectra (at spectral resolution R = 230 and R = 60, respectively) of MWC 419, a Herbig Ae/Be star. The data were obtained simultaneously with a new configuration of the 85 m baseline Keck Interferometer. Our observations are sensitive to the radial distribution of temperature in the inner region of the disk of MWC 419. We fit the visibility data with both simple geometric and more physical disk models. The geometric models (uniform disk and Gaussian) show that the apparent size increases linearly with wavelength in the 2-4 μm wavelength region, suggesting that the disk is extended with a temperature gradient. A model having a power-law temperature gradient with radius simultaneously fits our interferometric measurements and the spectral energy distribution data from the literature. The slope of the power law is close to that expected from an optically thick disk. Our spectrally dispersed interferometric measurements include the Br γ emission line. The measured disk size at and around Br γ suggests that emitting hydrogen gas is located inside (or within the inner regions) of the dust disk.

First L-Band Interferometric Observations of a Young Stellar Object: Probing the Circumstellar Environment of MWC 419

Science.gov (United States)

Ragland, S.; Akeson, R. L.; Armandroff, T.; Colavita, M. M.; Danchi, W. C.; Hillenbrand, L. A.; Millan-Gabet, R.; Ridgway, S. T.; Traub, W. A.; Vasisht, G.; Wizinowich, P. L.

2009-09-01

We present spatially resolved K- and L-band spectra (at spectral resolution R = 230 and R = 60, respectively) of MWC 419, a Herbig Ae/Be star. The data were obtained simultaneously with a new configuration of the 85 m baseline Keck Interferometer. Our observations are sensitive to the radial distribution of temperature in the inner region of the disk of MWC 419. We fit the visibility data with both simple geometric and more physical disk models. The geometric models (uniform disk and Gaussian) show that the apparent size increases linearly with wavelength in the 2-4 μm wavelength region, suggesting that the disk is extended with a temperature gradient. A model having a power-law temperature gradient with radius simultaneously fits our interferometric measurements and the spectral energy distribution data from the literature. The slope of the power law is close to that expected from an optically thick disk. Our spectrally dispersed interferometric measurements include the Br γ emission line. The measured disk size at and around Br γ suggests that emitting hydrogen gas is located inside (or within the inner regions) of the dust disk.

Geologic surface effects of underground nuclear testing, Yucca Flat, Nevada Test Site, Nevada; TOPICAL

International Nuclear Information System (INIS)

Grasso, D.N.

2000-01-01

This report presents a new Geographic Information System composite map of the geologic surface effects caused by underground nuclear testing in the Yucca Flat Physiographic Area of the Nevada Test Site, Nye County, Nevada. The Nevada Test Site (NTS) was established in 1951 as a continental location for testing nuclear devices (Allen and others, 1997, p.3). Originally known as the ''Nevada Proving Ground'', the NTS hosted a total of 928 nuclear detonations, of which 828 were conducted underground (U.S. Department of Energy, 1994). Three principal testing areas of the NTS were used: (1) Yucca Flat, (2) Pahute Mesa, and (3) Rainier Mesa including Aqueduct Mesa. Underground detonations at Yucca Flat and Pahute Mesa were typically emplaced in vertical drill holes, while others were tunnel emplacements. Of the three testing areas, Yucca Flat was the most extensively used, hosting 658 underground tests (747 detonations) located at 719 individual sites (Allen and others, 1997, p.3-4). Figure 1 shows the location of Yucca Flat and other testing areas of the NTS. Figure 2 shows the locations of underground nuclear detonation sites at Yucca Flat. Table 1 lists the number of underground nuclear detonations conducted, the number of borehole sites utilized, and the number of detonations mapped for surface effects at Yucca Flat by NTS Operational Area

Simultaneous refractive index and thickness measurement with the transmission interferometric adsorption sensor

Energy Technology Data Exchange (ETDEWEB)

Sannomiya, Takumi; Voeroes, Janos [Laboratory of Biosensors and Bioelectronics, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092, Zurich (Switzerland); Balmer, Tobias E [Materials Research Center, ETH Zurich, 8093, Zurich (Switzerland); Heuberger, Manfred, E-mail: sannomiya@biomed.ee.ethz.c, E-mail: tobias.balmer@mat.ethz.c, E-mail: manfred.heuberger@empa.c, E-mail: janos.voros@biomed.ee.ethz.c [Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093, Zurich (Switzerland)

2010-10-13

Refractive index and thickness of the adlayer are determined simultaneously using the transmission interferometric adsorption sensor (TInAS). Optical biosensors, where both refractive index and thickness of a homogeneous adlayer (thus the adsorbed mass) are determined simultaneously, so-called model-free biosensors, are important tools to investigate the adsorbed mass of biomolecules with unknown conformation. Our proposed calculation method enables model-free biosensing from a single spectrum acquired by a simple TInAS setup, namely using information of peak/dip positions as well as peak/dip intensities. The feasibility of this method was experimentally tested by adsorbing polyelectrolyte multilayer as well as biomolecules. To validate the new method also for the more intricate heterogeneous adlayer, the apparent refractive index and thickness were assessed theoretically by simulating a selection of different adsorbate configurations with the multiple multipole program (MMP). We found that a lateral inhomogeneity of the adsorbate (e.g. islands or adsorbed colloids) results in correct thickness and in reduced refractive index averaged in proportion to their density while vertically inhomogeneous density caused more complex responses. However, the apparent mass was always correct. Measurement errors can lead to significant errors in the apparent refractive index, particularly when the adlayer is very thin (<5 nm). This model-free TInAS technique would be useful not only for the measurement of adsorbed mass but also for the conformational analysis of the adsorbed molecules.

ACIGA's high optical power test facility

Energy Technology Data Exchange (ETDEWEB)

Ju, L [School of Physics, University of Western Australia, Perth (Australia); Aoun, M [Computer and Information Science, Edith Cowan University, Perth (Australia); Barriga, P [School of Physics, University of Western Australia, Perth (Australia)] [and others

2004-03-07

Advanced laser interferometer detectors utilizing more than 100 W of laser power and with {approx}10{sup 6} W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties.

HERO: a space based low frequency interferometric observatory for heliophysicsenabled by novel vector sensor technology

Science.gov (United States)

2017-04-07

baseline of HeRO-S or HeRO-G will detect type II and III solar bursts over several decades of intensity and frequency. Shown for comparison are an...and disturbances in a key region of the helio-11 sphere, from two to tens of solar radii, using interferometric observations of solar12 radio bursts at...fronts14 will be traced via type II burst emissions, and heliospheric magnetic field geometries15 will be probed by measuring precise trajectories of type

Surface moisture measurement system hardware acceptance test report

Energy Technology Data Exchange (ETDEWEB)

Ritter, G.A., Westinghouse Hanford

1996-05-28

This document summarizes the results of the hardware acceptance test for the Surface Moisture Measurement System (SMMS). This test verified that the mechanical and electrical features of the SMMS functioned as designed and that the unit is ready for field service. The bulk of hardware testing was performed at the 306E Facility in the 300 Area and the Fuels and Materials Examination Facility in the 400 Area. The SMMS was developed primarily in support of Tank Waste Remediation System (TWRS) Safety Programs for moisture measurement in organic and ferrocyanide watch list tanks.

Fatigue test results of straight pipe with flaws in inner surface

International Nuclear Information System (INIS)

Shibata, Katsuyuki; Oba, Toshihiro; Kawamura, Takaichi; Yokoyama, Norio; Miyazono, Shohachiro

1981-01-01

Fatigue and fracture tests of piping models with flaws in the inner surface were carried out to investigate the fatigue crack growth, coalescence of multiple cracks and fracture behavior. Two straight test pipes with and without weldment in the test section of SUS304L stainless steel were tested under almost the same test conditions. Three artificial defects were machined in the inner surface of the test section of the test pipes. The fatigue test were performed untill the cracks coalesced and grew through the thickness. Subsequently, a static load was imposed on test pipe which contained a large crack in the test section. The test results show that the fatigue crack growth is slower than that predicted by the method specified in the Section XI of ASME Boiler and Pressure Vessel Code, and that the test pipes can endure more than the static load of 3Sm without an unstable fracture. (author)

Site selection report basalt waste isolation program near-surface test facility

International Nuclear Information System (INIS)

Sharpe, S.D.

1978-01-01

A site selection committee was established to review the information gathered on potential sites and to select a site for the Near-Surface Test Facility Phase I. A decision was made to use a site on the north face of Gable Mountain located on the Hanford Site. This site provided convenient access to the Pomona Basalt Flow. This flow was selected for use at this site because it exhibited the characteristics established in the primary criteria. These criteria were: the flows thickness; its dryness; its nearness to the surface; and, its similarities to basalt units which are candidates for the repository. After the selection of the Near-Surface Test Facility Phase I Site, the need arose for an additional facility to demonstrate safe handling, storage techniques, and the physical effects of radioactive materials on an in situ basalt formation. The committee reviewed the sites selected for Phase I and chose the same site for locating Phase II of the Near-Surface Test Facility

Testing Augmented Reality Systems for Spotting Sub-Surface Impurities

DEFF Research Database (Denmark)

Hald, Kasper; Rehm, Matthias; Moeslund, Thomas B.

2018-01-01

This paper describes setup and procedure for testing augmented reality systems for showing sub-surface positions of foreign elements in an opaque mass. The goal is it test four types of setup in terms of user accuracy and speed, the four setups being a head-mounted see-through display, an arm...

CIT photoheliograph functional verification unit test program

Science.gov (United States)

1973-01-01

Tests of the 2/3-meter photoheliograph functional verification unit FVU were performed with the FVU installed in its Big Bear Solar Observatory vacuum chamber. Interferometric tests were run both in Newtonian (f/3.85) and Gregorian (f/50) configurations. Tests were run in both configurations with optical axis horizontal, vertical, and at 45 deg to attempt to determine any gravity effects on the system. Gravity effects, if present, were masked by scatter in the data associated with the system wavefront error of 0.16 lambda rms ( = 6328A) apparently due to problems in the primary mirror. Tests showed that the redesigned secondary mirror assembly works well.

Surface moisture measurement system hardware acceptance test procedure

International Nuclear Information System (INIS)

Ritter, G.A.

1996-01-01

The purpose of this acceptance test procedure is to verify that the mechanical and electrical features of the Surface Moisture Measurement System are operating as designed and that the unit is ready for field service. This procedure will be used in conjunction with a software acceptance test procedure, which addresses testing of software and electrical features not addressed in this document. Hardware testing will be performed at the 306E Facility in the 300 Area and the Fuels and Materials Examination Facility in the 400 Area. These systems were developed primarily in support of Tank Waste Remediation System (TWRS) Safety Programs for moisture measurement in organic and ferrocyanide watch list tanks

DNA conformation on surfaces measured by fluorescence self-interference.

Science.gov (United States)

Moiseev, Lev; Unlü, M Selim; Swan, Anna K; Goldberg, Bennett B; Cantor, Charles R

2006-02-21

The conformation of DNA molecules tethered to the surface of a microarray may significantly affect the efficiency of hybridization. Although a number of methods have been applied to determine the structure of the DNA layer, they are not very sensitive to variations in the shape of DNA molecules. Here we describe the application of an interferometric technique called spectral self-interference fluorescence microscopy to the precise measurement of the average location of a fluorescent label in a DNA layer relative to the surface and thus determine specific information on the conformation of the surface-bound DNA molecules. Using spectral self-interference fluorescence microscopy, we have estimated the shape of coiled single-stranded DNA, the average tilt of double-stranded DNA of different lengths, and the amount of hybridization. The data provide important proofs of concept for the capabilities of novel optical surface analytical methods of the molecular disposition of DNA on surfaces. The determination of DNA conformations on surfaces and hybridization behavior provide information required to move DNA interfacial applications forward and thus impact emerging clinical and biotechnological fields.

How to estimate the differential acceleration in a two-species atom interferometer to test the equivalence principle

Energy Technology Data Exchange (ETDEWEB)

Varoquaux, G; Nyman, R A; Geiger, R; Cheinet, P; Bouyer, P [Laboratoire Charles Fabry de l' Institut d' Optique, Campus Polytechnique, RD 128, 91127 Palaiseau (France); Landragin, A [LNE-SYRTE, UMR8630, UPMC, Observatoire de Paris, 61 avenue de l' Observatoire, 75014 Paris (France)], E-mail: philippe.bouyer@institutoptique.fr

2009-11-15

We propose a scheme for testing the weak equivalence principle (universality of free-fall (UFF)) using an atom-interferometric measurement of the local differential acceleration between two atomic species with a large mass ratio as test masses. An apparatus in free fall can be used to track atomic free-fall trajectories over large distances. We show how the differential acceleration can be extracted from the interferometric signal using Bayesian statistical estimation, even in the case of a large mass and laser wavelength difference. We show that this statistical estimation method does not suffer from acceleration noise of the platform and does not require repeatable experimental conditions. We specialize our discussion to a dual potassium/rubidium interferometer and extend our protocol with other atomic mixtures. Finally, we discuss the performance of the UFF test developed for the free-fall (zero-gravity) airplane in the ICE project (http://www.ice-space.fr)

How to estimate the differential acceleration in a two-species atom interferometer to test the equivalence principle

International Nuclear Information System (INIS)

Varoquaux, G; Nyman, R A; Geiger, R; Cheinet, P; Bouyer, P; Landragin, A

2009-01-01

We propose a scheme for testing the weak equivalence principle (universality of free-fall (UFF)) using an atom-interferometric measurement of the local differential acceleration between two atomic species with a large mass ratio as test masses. An apparatus in free fall can be used to track atomic free-fall trajectories over large distances. We show how the differential acceleration can be extracted from the interferometric signal using Bayesian statistical estimation, even in the case of a large mass and laser wavelength difference. We show that this statistical estimation method does not suffer from acceleration noise of the platform and does not require repeatable experimental conditions. We specialize our discussion to a dual potassium/rubidium interferometer and extend our protocol with other atomic mixtures. Finally, we discuss the performance of the UFF test developed for the free-fall (zero-gravity) airplane in the ICE project (http://www.ice-space.fr).

River Delta Subsidence Measured with Interferometric Synthetic Aperture Radar (InSAR)

Science.gov (United States)

Higgins, Stephanie

This thesis addresses the need for high-resolution subsidence maps of major world river deltas. Driven by a combination of rising water, sediment compaction, and reduced sediment supply due to damming and flood control, many deltas are sinking relative to sea level. A lack of data constraining rates and patterns of subsidence has made it difficult to determine the relative contributions of each factor in any given delta, however, or to assess whether the primary drivers of land subsidence are natural or anthropogenic. In recent years, Interferometric Synthetic Aperture Radar (InSAR) has emerged as a satellite-based technique that can map ground deformation with mm-scale accuracy over thousands of square kilometers. These maps could provide critical insight into the drivers of subsidence in deltas, but InSAR is not typically applied to non-urban delta areas due to the difficulties of performing the technique in wet, vegetated settings. This thesis addresses those difficulties and achieves high-resolution measurements of ground deformation in rural deltaic areas. Chapter 1 introduces the processes that drive relative sea level rise in river deltas and investigates open questions in delta subsidence research. Chapter 2 assesses the performance of InSAR in delta settings and reviews interferogram generation in the context of delta analysis, presenting delta-specific processing details and guiding interpretation in these challenging areas. Chapter 3 applies Differential (D-) InSAR to the coast of the Yellow River Delta in China. Results show that subsidence rates are as high as 250 mm/y due to groundwater extraction at aquaculture facilities, a rate that exceeds local and global average sea level rise by nearly two orders of magnitude and suggests a significant hazard for Asian megadeltas. Chapter 4 applies interferometric stacking and Small Baseline Subset (SBAS)-InSAR to the Ganges-Brahmaputra Delta, Bangladesh. Results show that stratigraphy controls subsidence in

Repeat-Pass Multi-Temporal Interferometric SAR Coherence Variations with Amazon Floodplain and Lake Habitats

Science.gov (United States)

Jung, H.; Alsdorf, D.

2006-12-01

Monitoring discharge in the main channels of rivers and upland tributaries as well as storage changes in floodplain lakes is necessary for understanding flooding hazards, methane production, sediment transport, and nutrient exchange. Interferometric processing of synthetic aperture radar (SAR) data may enable hydrologists to detect environmental and ecological changes in hydrological systems over space and time. An aim of our experiments is to characterize interferometric SAR coherence variations that occur in Amazon aquatic habitats. We analyze coherence variations in JERS-1 data at three central Amazon sites; Lake Balbina, the Cabaliana floodplain, and the confluence of the Purus and Amazon rivers. Because radar pulse interactions with inundated vegetation typically follow a double-bounce travel path which returns energy to the antenna, coherence will vary with vegetation type, physical baseline, and temporal baseline. Balbina's vegetation consists mostly of forest and inundated trunks of dead, leafless trees as opposed to Cabaliana and Amazon- Purus (dominated by flooded forests), thus it serves to isolate the vegetation signal. Coherence variations with baselines were determined from 253 interferograms at Balbina, 210 at Calbaliana, and 153 at Purus. The average temporal and perpendicular baselines (mean std.) are 574 394 days and 1708 1159 m at Balbina, 637 435 days and 1381 981 m at Cabaliana, and 587 425 days and 1430 964 m at Purus. Balbina has a stronger coherence than either Cabaliana or Amazon-Purus. With results of Mann-Whitney statistical tests, Balbina has a difference between terre-firme and flooded coherence values plotted with perpendicular baseline but Cabaliana and Amazon-Purus do not show this difference. Balbina has a linearly decreasing trend in coherence plotted with temporal baseline whereas Cabaliana and Amazon-Purus have a steep drop-off, non- linear change. A strong annual periodicity is evident on power spectrums of the coherence values

The 2001 U.S. Naval Observatory Double Star CD-Rom. III. The Third Catalog of Interferometric Measurements of Binary Stars

Science.gov (United States)

2001-12-01

CHARA southern speckle program from 1989 to 1996 (cf. Hartkopf et al. 1996), and by the more recent speckle e†orts of Horch and colleagues (cf. Horch ...Mason, B. D. 2001, Third Catalog of Interferometric Measurements of Binary Stars (CHARA Contrib. No. 4) (Atlanta : Georgia State Univ.) Horch , E

Towards corrosion testing of unglazed solar absorber surfaces in simulated acid rain

International Nuclear Information System (INIS)

Salo, T.; Pehkonen, A.; Konttinen, P.; Lund, P.

2005-01-01

Electrochemical impedance spectroscopy and potentiodynamic polarization tests were utilized for determining corrosion probabilities of unglazed C/Al 2 O 3 /Al solar absorber surfaces in simulated acid rain. Previously, the main degradation mechanism found was exponentially temperature-related hydration of aluminium oxide. In acid rain tests the main corrosion determinant was the pH value of the rain. Results indicate that these methods measure corrosion characteristics of Al substrate instead of the C/Al 2 O 3 /Al surface, probably mainly due to the rough and non-uniform microstructure of the latter. Further analyses of the test methods are required in order to estimate their applicability on Al-based uniform sputtered absorber surfaces. (author) (C/Al 2 O 3 /Al solar absorber; Acid rain; Corrosion; Electrochemical tests)

Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

Science.gov (United States)

L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker

2013-01-01

Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

Surface Disturbances at the Punggye-ri Nuclear Test Site: Another Indicator of Nuclear Testing?

Energy Technology Data Exchange (ETDEWEB)

Pabian, Frank V. [Los Alamos National Laboratory; Coblentz, David [Los Alamos National Laboratory

2017-02-03

A review of available very high-resolution commercial satellite imagery (bracketing the time of North Korea’s most recent underground nuclear test on 9 September 2016 at the Punggye-ri Underground Nuclear Test Site) has led to the detection and identification of several minor surface disturbances on the southern flank of Mt. Mantap. These surface disturbances occur in the form of small landslides, either alone or together with small zones of disturbed bare rock that appear to have been vertically lofted (“spalled”) as a result of the most recent underground explosion. Typically, spall can be uniquely attributed to underground nuclear testing and is not a result of natural processes. However, given the time gap of up to three months between images (pre- and post-event), which was coincident with a period of heavy typhoon flooding in the area1, it is not possible to determine whether the small landslides were exclusively explosion induced, the consequence of heavy rainfall erosion, or some combination of the two.

Testing the performance of a blind burst statistic

Energy Technology Data Exchange (ETDEWEB)

Vicere, A [Istituto di Fisica, Universita di Urbino (Italy); Calamai, G [Istituto Nazionale di Fisica Nucleare, Sez. Firenze/Urbino (Italy); Campagna, E [Istituto Nazionale di Fisica Nucleare, Sez. Firenze/Urbino (Italy); Conforto, G [Istituto di Fisica, Universita di Urbino (Italy); Cuoco, E [Istituto Nazionale di Fisica Nucleare, Sez. Firenze/Urbino (Italy); Dominici, P [Istituto di Fisica, Universita di Urbino (Italy); Fiori, I [Istituto di Fisica, Universita di Urbino (Italy); Guidi, G M [Istituto di Fisica, Universita di Urbino (Italy); Losurdo, G [Istituto Nazionale di Fisica Nucleare, Sez. Firenze/Urbino (Italy); Martelli, F [Istituto di Fisica, Universita di Urbino (Italy); Mazzoni, M [Istituto Nazionale di Fisica Nucleare, Sez. Firenze/Urbino (Italy); Perniola, B [Istituto di Fisica, Universita di Urbino (Italy); Stanga, R [Istituto Nazionale di Fisica Nucleare, Sez. Firenze/Urbino (Italy); Vetrano, F [Istituto di Fisica, Universita di Urbino (Italy)

2003-09-07

In this work, we estimate the performance of a method for the detection of burst events in the data produced by interferometric gravitational wave detectors. We compute the receiver operating characteristics in the specific case of a simulated noise having the spectral density expected for Virgo, using test signals taken from a library of possible waveforms emitted during the collapse of the core of type II supernovae.

Modelling of XCO2 Surfaces Based on Flight Tests of TanSat Instruments

Directory of Open Access Journals (Sweden)

Li Li Zhang

2016-11-01

Full Text Available The TanSat carbon satellite is to be launched at the end of 2016. In order to verify the performance of its instruments, a flight test of TanSat instruments was conducted in Jilin Province in September, 2015. The flight test area covered a total area of about 11,000 km2 and the underlying surface cover included several lakes, forest land, grassland, wetland, farmland, a thermal power plant and numerous cities and villages. We modeled the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO2 surface based on flight test data which measured the near- and short-wave infrared (NIR reflected solar radiation in the absorption bands at around 760 and 1610 nm. However, it is difficult to directly analyze the spatial distribution of XCO2 in the flight area using the limited flight test data and the approximate surface of XCO2, which was obtained by regression modeling, which is not very accurate either. We therefore used the high accuracy surface modeling (HASM platform to fill the gaps where there is no information on XCO2 in the flight test area, which takes the approximate surface of XCO2 as its driving field and the XCO2 observations retrieved from the flight test as its optimum control constraints. High accuracy surfaces of XCO2 were constructed with HASM based on the flight’s observations. The results showed that the mean XCO2 in the flight test area is about 400 ppm and that XCO2 over urban areas is much higher than in other places. Compared with OCO-2’s XCO2, the mean difference is 0.7 ppm and the standard deviation is 0.95 ppm. Therefore, the modelling of the XCO2 surface based on the flight test of the TanSat instruments fell within an expected and acceptable range.

A three-dimensional sorting reliability algorithm for coastline deformation monitoring, using interferometric data

International Nuclear Information System (INIS)

Genderen, J v; Marghany, M

2014-01-01

The paper focusses on three-dimensional (3-D) coastline deformation using interferometric synthetic aperture radar data(InSAR). Conventional InSAR procedures were implemented on three repeat passes of ENVISAT ASAR data. Furthermore, the three-dimensional sorting reliabilities algorithm (3D-SRA) were implemented with the phase unwrapping technique. Subsequently, the 3D-SRA was used to eliminate the phase decorrelation impact from the interferograms. The study showed that the performance of the InSAR method using the 3D-SRA algorithm, is better than the conventional InSAR procedure. In conclusion, the integration of the 3D-SRA, together with phase unwrapping, can produce accurate 3-D coastline deformation information

Standard test method for calibration of surface/stress measuring devices

CERN Document Server

American Society for Testing and Materials. Philadelphia

1997-01-01

Return to Contents page 1.1 This test method covers calibration or verification of calibration, or both, of surface-stress measuring devices used to measure stress in annealed and heat-strengthened or tempered glass using polariscopic or refractometry based principles. 1.2 This test method is nondestructive. 1.3 This test method uses transmitted light, and therefore, is applicable to light-transmitting glasses. 1.4 This test method is not applicable to chemically tempered glass. 1.5 Using the procedure described, surface stresses can be measured only on the “tin” side of float glass. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Heater test planning for the Near Surface Test Facility at the Hanford reservation. Volume II. Appendix

International Nuclear Information System (INIS)

DuBois, A.; Binnall, E.; Chan, T.; McEvoy, M.; Nelson, P.; Remer, J.

1979-04-01

Volume II contains the following information: theoretical support for radioactive waste storage projects - development of data analysis methods and numerical models; injectivity temperature profiling as a means of permeability characterization; geophysical holes at the Near Surface Test Facility (NSTF), Hanford; proposed geophysical and hydrological measurements at NSTF; suggestions for characterization of the discontinuity system at NSTF; monitoring rock property changes caused by radioactive waste storage using the electrical resistivity method; microseismic detection system for heated rock; Pasco Basin groundwater contamination study; a letter to Mark Board on Gable Mountain Faulting; report on hydrofracturing tests for in-situ stress measurement, NSTF, Hole DC-11, Hanford Reservation; and borehole instrumentation layout for Hanford Near Surface Test Facility

Characterisation and full-scale production testing of multifunctional surfaces for deep drawing applications

DEFF Research Database (Denmark)

Godi, Alessandro; Grønbæk, J.; De Chiffre, Leonardo

2017-01-01

assisted polishing. Advanced methods are employed to characterise the tools' surface topographies, detecting the surface features and analysing them separately according to their specific function. Four different multifunctional dies as well as two un-textured references are selected for testing. The tests......Full-scale deep drawing tests using tools featuring multifunctional surfaces are carried out in a production environment. Multifunctional tools display regularly spaced, transversal grooves for lubricant retention obtained by hard-turning, separated by smooth bearing plateaus realized by robot...

Interferometric characterization of tear film dynamics

Science.gov (United States)

Primeau, Brian Christopher

The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. When a contact lens is on worn, the tear film covers the contact lens as it would a bare cornea, and is affected by the contact lens material properties. Tear film irregularity can cause both discomfort and vision quality degradation. Under normal conditions, the tear film is less than 10 microns thick and the thickness and topography change in the time between blinks. In order to both better understand the tear film, and to characterize how contact lenses affect tear film behavior, two interferometers were designed and built to separately measure tear film behavior in vitro and in vivo. An in vitro method of characterizing dynamic fluid layers applied to contact lenses mounted on mechanical substrates has been developed using a phase-shifting Twyman-Green interferometer. This interferometer continuously measures light reflected from the surface of the fluid layer, allowing precision analysis of the dynamic fluid layer. Movies showing this fluid layer behavior can be generated. The fluid behavior on the contact lens surface is measured, allowing quantitative analysis beyond what typical contact angle or visual inspection methods provide. The in vivo interferometer is a similar system, with additional modules included to provide capability for human testing. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or videokeratometry and provides better sensitivity and resolution than shearing interferometry methods.

DISCRETIZATION APPROACH USING RAY-TESTING MODEL IN PARTING LINE AND PARTING SURFACE GENERATION

Institute of Scientific and Technical Information of China (English)

HAN Jianwen; JIAN Bin; YAN Guangrong; LEI Yi

2007-01-01

Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in automatic cavity design based on the ray-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.

Quantitative test for concave aspheric surfaces using a Babinet compensator.

Science.gov (United States)

Saxena, A K

1979-08-15

A quantitative test for the evaluation of surface figures of concave aspheric surfaces using a Babinet compensator is reported. A theoretical estimate of the sensitivity is 0.002lambda for a minimum detectable phase change of 2 pi x 10(-3) rad over a segment length of 1.0 cm.

Measuring test mass acceleration noise in space-based gravitational wave astronomy

Science.gov (United States)

Congedo, Giuseppe

2015-03-01

The basic constituent of interferometric gravitational wave detectors—the test-mass-to-test-mass interferometric link—behaves as a differential dynamometer measuring effective differential forces, comprising an integrated measure of gravity curvature, inertial effects, as well as nongravitational spurious forces. This last contribution is going to be characterized by the LISA Pathfinder mission, a technology precursor of future space-borne detectors like eLISA. Changing the perspective from displacement to acceleration can benefit the data analysis of LISA Pathfinder and future detectors. The response in differential acceleration to gravitational waves is derived for a space-based detector's interferometric link. The acceleration formalism can also be integrated into time delay interferometry by building up the unequal-arm Michelson differential acceleration combination. The differential acceleration is nominally insensitive to the system's free evolution dominating the slow displacement dynamics of low-frequency detectors. Working with acceleration also provides an effective way to subtract measured signals acting as systematics, including the actuation forces. Because of the strong similarity with the equations of motion, the optimal subtraction of systematic signals, known within some amplitude and time shift, with the focus on measuring the noise provides an effective way to solve the problem and marginalize over nuisance parameters. The F statistic, in widespread use throughout the gravitation waves community, is included in the method and suitably generalized to marginalize over linear parameters and noise at the same time. The method is applied to LPF simulator data and, thanks to its generality, can also be applied to the data reduction and analysis of future gravitational wave detectors.

Combination of a fast white-light interferometer with a phase shifting interferometric line sensor for form measurements of precision components

Science.gov (United States)

Laubach, Sören; Ehret, Gerd; Riebling, Jörg; Lehmann, Peter

2017-06-01

By means of an interferometric line sensor system, the form of a specimen can be measured by stitching several overlapping circular subapertures to form one 3D topography. This concept is very flexible and can be adapted to many different specimen geometries. The sensor is based on a Michelson interferometer configuration that consists of a rapidly oscillating reference mirror in combination with a high-speed line-scan camera. Due to the overlapping areas, movement errors of the scan axes can be corrected. In order to automatically adjust the line sensor in such a way that it is perpendicular to the measurement surface at a fixed working distance, a white-light interferometer was included in the line-based form-measuring system. By means of a fast white-light scan, the optimum angle of the sensor (with respect to the surface of the specimen) is determined in advance, before scanning the specimen using the line-based sinusoidal phase shifting interferometer. This produces accurate measurement results and makes it possible to also measure non-rotational specimens. In this paper, the setup of the line-based form-measuring system is introduced and the measurement strategy of the sensor adjustment using an additional white-light interferometer is presented. Furthermore, the traceability chain of the system and the main error influences are discussed. Examples of form measurement results are shown.

Interferometric imaging of the 2011-2013 Campi Flegrei unrest

Science.gov (United States)

De Siena, Luca; Nakahara, Hisashi; Zaccarelli, Lucia; Sammarco, Carmelo; La Rocca, Mario; Bianco, Francesca

2017-04-01

After its 1983-84 seismic and deformation crisis, seismologists have recorded very low and clustered seismicity at Campi Flegrei caldera (Italy). Hence, noise interferometry imaging has become the only option to image the present volcano logical state of the volcano. Three-component noise data recorded before, during, and after Campi Flegrei last deformation and geochemical unrest (2011-2013) have thus been processed with up-to-date interferometric imaging workflow based on MSNoise. Noise anisotropy, which strongly affects measurements throughout the caldera at all frequencies, has been accounted for by self-correlation measurements and smoothed by phase weighted stacking and phase-match filtering. The final group-velocity maps show strong low-velocity anomalies at the location of the last Campi Flegrei eruption (1538 A.D.). The main low-velocity anomalies contour Solfatara volcano and follow geomorphological cross-faulting. The comparison with geophysical imaging results obtained during the last seismic unrest at the caldera suggest strong changes in the physical properties of the volcano, particularly in the area of major hydrogeological hazard.

Quantifying sub-pixel urban impervious surface through fusion of optical and inSAR imagery

Science.gov (United States)

Yang, L.; Jiang, L.; Lin, H.; Liao, M.

2009-01-01

In this study, we explored the potential to improve urban impervious surface modeling and mapping with the synergistic use of optical and Interferometric Synthetic Aperture Radar (InSAR) imagery. We used a Classification and Regression Tree (CART)-based approach to test the feasibility and accuracy of quantifying Impervious Surface Percentage (ISP) using four spectral bands of SPOT 5 high-resolution geometric (HRG) imagery and three parameters derived from the European Remote Sensing (ERS)-2 Single Look Complex (SLC) SAR image pair. Validated by an independent ISP reference dataset derived from the 33 cm-resolution digital aerial photographs, results show that the addition of InSAR data reduced the ISP modeling error rate from 15.5% to 12.9% and increased the correlation coefficient from 0.71 to 0.77. Spatially, the improvement is especially noted in areas of vacant land and bare ground, which were incorrectly mapped as urban impervious surfaces when using the optical remote sensing data. In addition, the accuracy of ISP prediction using InSAR images alone is only marginally less than that obtained by using SPOT imagery. The finding indicates the potential of using InSAR data for frequent monitoring of urban settings located in cloud-prone areas.

Tunable coherent radiation at soft X-ray wavelengths: Generation and interferometric applications

International Nuclear Information System (INIS)

Rosfjord, Kristine Marie

2004-01-01

The availability of high power, spectrally and spatially coherent soft x-rays (SXR) would facilitate a wide variety of experiments as this energy region covers the primary resonances of many magnetic and biological materials. Specifically, there are the carbon and oxygen K-edges that are critical for biological imaging in the water window and the L-edges of iron, nickel, and cobalt for which imaging and scattering studies can be performed. A new coherent soft X-ray branchline at the Advanced Light Source has begun operation (beamline 12.0.2). Using the third harmonic from an 8 cm period undulator, this branch delivers coherent soft x-rays with photon energies ranging from 200eV to 1keV. This branchline is composed of two sub-branches one at 14X demagnification and the other 8X demagnification. The former is optimized for use at 500eV and the latter at 800eV. Here the expected power from the third harmonic of this undulator and the beamline design and characterization is presented. The characterization includes measurements on available photon flux as well as a series of double pinhole experiments to determine the coherence factor with respect to transverse distance. The first high quality Airy patterns at SXR wavelengths are created with this new beamline. The operation of this new beamline allows for interferometry to be performed in the SXR region. Here an interferometric experiment designed to directly determine the index of refraction of a material under test is performed. Measurements are first made in the EUV region using an established beamline (beamline12.0.1) to measure silicon, ruthenium and tantalum silicon nitride. This work is then extended to the SXR region using beamline 12.0.2 to test chromium and vanadium

Tunable coherent radiation at soft X-ray wavelengths: Generation and interferometric applications

Energy Technology Data Exchange (ETDEWEB)

Rosfjord, Kristine Marie [Univ. of California, Berkeley, CA (United States)

2004-01-01

The availability of high power, spectrally and spatially coherent soft x-rays (SXR) would facilitate a wide variety of experiments as this energy region covers the primary resonances of many magnetic and biological materials. Specifically, there are the carbon and oxygen K-edges that are critical for biological imaging in the water window and the L-edges of iron, nickel, and cobalt for which imaging and scattering studies can be performed. A new coherent soft X-ray branchline at the Advanced Light Source has begun operation (beamline 12.0.2). Using the third harmonic from an 8 cm period undulator, this branch delivers coherent soft x-rays with photon energies ranging from 200eV to 1keV. This branchline is composed of two sub-branches one at 14X demagnification and the other 8X demagnification. The former is optimized for use at 500eV and the latter at 800eV. Here the expected power from the third harmonic of this undulator and the beamline design and characterization is presented. The characterization includes measurements on available photon flux as well as a series of double pinhole experiments to determine the coherence factor with respect to transverse distance. The first high quality Airy patterns at SXR wavelengths are created with this new beamline. The operation of this new beamline allows for interferometry to be performed in the SXR region. Here an interferometric experiment designed to directly determine the index of refraction of a material under test is performed. Measurements are first made in the EUV region using an established beamline (beamline12.0.1) to measure silicon, ruthenium and tantalum silicon nitride. This work is then extended to the SXR region using beamline 12.0.2 to test chromium and vanadium.

Ground-based gravitational wave interferometric detectors of the first and second generation: an overview

International Nuclear Information System (INIS)

Losurdo, Giovanni

2012-01-01

The era of first-generation gravitational wave interferometric detectors is ending. No signals have been detected so far. However, remarkable results have been achieved: the design sensitivity has been approached (and in some cases even exceeded) together with the achievement of robustness and reliability; a world-wide network of detectors has been established; the data collected so far has allowed upper limits to be put on several types of sources; some second-generation technologies have been tested on these detectors. The scenario for the next few years is very exciting. The projects to upgrade LIGO and Virgo to second-generation interferometers, capable of increasing the detection rate by a factor of ∼1000, have been funded. The construction of Advanced LIGO and Advanced Virgo has started. GEO600 has started the upgrade to GEO HF, introducing light squeezing for the first time on a large detector. LCGT has been partly funded and the construction of the vacuum system is underway. There is a possibility that the third Advanced LIGO interferometer will be constructed in India. So, a powerful worldwide network could be in operation by the end of the decade. In this paper, we review the results achieved so far and the perspectives for the advanced detectors. (paper)

The use of Interferometric Microscopy to assess 3D modifications of deteriorated medieval glass.

Science.gov (United States)

Gentaz, L.; Lombardo, T.; Chabas, A.

2012-04-01

Due to low durability, Northern European medieval glass undergoes the action of the atmospheric environment leading in some cases to a state of dramatic deterioration. Modification features varies from a simple loss of transparency to a severe material loss. In order to understand the underlying mechanisms and preserve this heritage, fundamental research is necessary too. In this optic, field exposure of analogues and original stained glass was carried out to study the early stages of the glass weathering. Model glass and original stained glass (after removal of deterioration products) were exposed in real conditions in an urban site (Paris) for 48 months. A regular withdrawal of samples allowed a follow-up of short-term glass evolution. Morphological modifications of the exposed samples were investigated through conventional and non destructive microscopy, using respectively a Scanning Electron Microscope (SEM) and an Interferometric Microscope (IM). This latter allows a 3D quantification of the object with no sample preparation. For all glasses, both surface recession and build-up of deposit were observed as a consequence of a leaching process (interdiffusion of protons and glass cations). The build-up of a deposit comes from the reaction between the extracted glass cations and atmospheric gases. Instead, surface recession is due mainly to the formation of brittle layer of altered glass at the sub-surface, where a fracture network can appear, leading to the scaling of parts of this modified glass. Finally, dissolution of the glass takes place, inducing the formation of pits and craters. The arithmetic roughness (Ra) was used as an indicator of weathering increase, in order to evaluate the deterioration state. For instance, the Ra grew from few tens of nm for pristine glass to thousands of nm for scaled areas. This technique also allowed a precise quantification of dimensions (height, depth and width) of deposits and pits, and the estimation of their overall

Evaluation of Surface Infiltration Testing Procedures in Permeable Pavement Systems

Science.gov (United States)

The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete provides limited guidance on how to select testing locations, so research is needed to evaluate how testing sites should be selected and how results should be interpreted to assess surface ...

Change Detection by Interferometric Coherence in Nasca Lines, Peru (1997-2004)

Science.gov (United States)

Ruescas, Ana B.; Delgado, J. Manuel; Costantini, Fabiano; Sarti, Francesco

2010-03-01

Two interferometric pairs of Synthetic Aperture Radar (SAR) images are used to generate coherence images of the Nasca Lines Pampa area. The first coherence image is based on a pair of ERS-2 SAR data from 1997 and 1999; the second one is computed from two ENVISAT-ASAR (Advanced SAR) images from 2003 and 2004. The main objective is to study the changes in the coherence values in different parts of the area. Several different decorrelation factors contributing to a loss of coherency in a radar pair can be distinguished, and these include the temporal change in the ground properties and nature between the two satellite passes. In order to do this discrimination and interpretation, some ancillary data can be used, such as optical data from the Advanced Land Observing Satellite (ALOS), and meteorological data from the Global Precipitation Climatology Center (GPCC).

Heat transfer tests of ribbed surfaces for gas-cooled reactors

International Nuclear Information System (INIS)

Klepper, O.H.

1975-07-01

The performance of gas-cooled reactors is often limited by the heat transfer in the reactor core. Means for modifying core heat transfer surfaces to improve their performance were investigated. The 0.3-in.-OD stainless steel clad heater rods were photo-etched to produce external ribs 0.006 in. high and 0.12 in. wide with a pitch of 0.072 in. Helical ribs with a helix angle of 37 0 (to promote interchannel flow mixing in a multirod array) were provided on one surface. For comparison purposes, a transversely ribbed surface and a smooth rod were also studied. The test surfaces were 49 in. long with a 24-in. heated region, concentrically arranged inside a smooth 0.602-in.-ID stainless steel tube. Nitrogen gas at pressures up to 400 psig was used as the coolant; the linear heat rating ranged to 6.8 kW/ft at surface temperatures up to 1400 0 F; T/sub w/T/sub b/ varied from 1.2 to 2.4 at Re values up to 450,000. Annulus results were recalculated for rod geometry using two different transformations. Good agreement was observed with applicable literature values. The effectiveness of the surfaces was assessed as the ratio E of the heat transfer coefficients of the roughened rods to that of a smooth rod at the same pumping power. The effectiveness of the spiral ribs ranged from 1.3 to 1.4, and from 1.2 to 1.4 for the transverse ribs, spanning Re values from 60,000 to 400,000. These data include variations introduced by alternate transformation methods that were used to make annulus test results applicable to rod geometry. The surfaces investigated in these tests were considered for fast gas-cooled reactors; however, the range of parameters studied also applies to heat transfer from ribbed rod-type fuel elements in thermal gas-cooled reactors. (U.S.)

Characterization of electron microscopes with binary pseudo-random multilayer test samples

Science.gov (United States)

Yashchuk, Valeriy V.; Conley, Raymond; Anderson, Erik H.; Barber, Samuel K.; Bouet, Nathalie; McKinney, Wayne R.; Takacs, Peter Z.; Voronov, Dmitriy L.

2011-09-01

Verification of the reliability of metrology data from high quality X-ray optics requires that adequate methods for test and calibration of the instruments be developed. For such verification for optical surface profilometers in the spatial frequency domain, a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays has been suggested [1,2] and proven to be an effective calibration method for a number of interferometric microscopes, a phase shifting Fizeau interferometer, and a scatterometer [5]. Here we describe the details of development of binary pseudo-random multilayer (BPRML) test samples suitable for characterization of scanning (SEM) and transmission (TEM) electron microscopes. We discuss the results of TEM measurements with the BPRML test samples fabricated from a WiSi 2/Si multilayer coating with pseudo-randomly distributed layers. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML test samples can be used to characterize X-ray microscopes. Corresponding work with X-ray microscopes is in progress.

Characterization of electron microscopes with binary pseudo-random multilayer test samples

International Nuclear Information System (INIS)

Yashchuk, Valeriy V.; Conley, Raymond; Anderson, Erik H.; Barber, Samuel K.; Bouet, Nathalie; McKinney, Wayne R.; Takacs, Peter Z.; Voronov, Dmitriy L.

2011-01-01

Verification of the reliability of metrology data from high quality X-ray optics requires that adequate methods for test and calibration of the instruments be developed. For such verification for optical surface profilometers in the spatial frequency domain, a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays has been suggested and proven to be an effective calibration method for a number of interferometric microscopes, a phase shifting Fizeau interferometer, and a scatterometer [5]. Here we describe the details of development of binary pseudo-random multilayer (BPRML) test samples suitable for characterization of scanning (SEM) and transmission (TEM) electron microscopes. We discuss the results of TEM measurements with the BPRML test samples fabricated from a WiSi 2 /Si multilayer coating with pseudo-randomly distributed layers. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML test samples can be used to characterize X-ray microscopes. Corresponding work with X-ray microscopes is in progress.

Effective Inertial Frame in an Atom Interferometric Test of the Equivalence Principle

Science.gov (United States)

Overstreet, Chris; Asenbaum, Peter; Kovachy, Tim; Notermans, Remy; Hogan, Jason M.; Kasevich, Mark A.

2018-05-01

In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. Here we demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. Using this method, we suppress the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by 2 orders of magnitude and precisely measure these differences. We realize a relative precision of Δ g /g ≈6 ×10-11 per shot, which improves on the best previous result for a dual-species atom interferometer by more than 3 orders of magnitude. By reducing gravity gradient systematic errors to one part in 1 013 , these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests.

INTERFACE DEVICE FOR NONDESTRUCTIVE TESTING OF RESIDUAL SURFACE STRESSES

Directory of Open Access Journals (Sweden)

Gennady A. Perepelkin

2016-01-01

Full Text Available The paper considers the organization of connection of a personal computer with a device for nondestructive testing of residual surface stresses. The device works is based on the phenomenon of diffraction of ionizing radiation from the crystal lattice near the surface of the crystallites. Proposed software interface to the organization for each type of user: the device developers, administrators, users. Some aspects of the organization of communication microcontroller to a PC via USB-port

Characterization of holding brake friction pad surface after pin-on-plate wear test

DEFF Research Database (Denmark)

Drago, N.; Gonzalez Madruga, D.; De Chiffre, L.

2018-01-01

This article concerns the metrological characterization of the surface on a holding brake friction material pin after a pin-on-plate (POP) wear test. The POP test induces the formation of surface plateaus that affect brake performances such as wear, friction, noise and heat. Three different...

A differential optical interferometer for measuring short pulses of surface acoustic waves.

Science.gov (United States)

Shaw, Anurupa; Teyssieux, Damien; Laude, Vincent

2017-09-01

The measurement of the displacements caused by the propagation of a short pulse of surface acoustic waves on a solid substrate is investigated. A stabilized time-domain differential interferometer is proposed, with the surface acoustic wave (SAW) sample placed outside the interferometer. Experiments are conducted with surface acoustic waves excited by a chirped interdigital transducer on a piezoelectric lithium niobate substrate having an operational bandwidth covering the 200-400MHz frequency range and producing 10-ns pulses with 36nm maximum out-of-plane displacement. The interferometric response is compared with a direct electrical measurement obtained with a receiving wide bandwidth interdigital transducer and good correspondence is observed. The effects of varying the path difference of the interferometer and the measurement position on the surface are discussed. Pulse compression along the chirped interdigital transducer is observed experimentally. Copyright © 2017 Elsevier B.V. All rights reserved.

Radioactive contamination of some rubber or plastic surfaces by fission products. Decontamination tests

International Nuclear Information System (INIS)

Mestre, E.; Sautiez, N.

1957-10-01

With the objective of notably addressing the contamination and decontamination of gloves and floor covering, this report first presents some characteristics of contaminating radioactive materials (nature, physical and chemical condition), of contaminated surfaces (surface condition, surface nature), and of decontamination processes (physical, chemical or mechanical action). It describes the operational modality implemented to test decontamination processes on various glove or flooring materials: sample preparation, counting, decontamination, reproducibility of decontamination tests, results in terms of activity reduction. It more precisely describes the tested samples: short gloves, gloves from glove boxes, floor and wall coverings. Results are presented and discussed in terms of sample susceptibility to contamination, and of decontamination, but also for re-contamination tests after a Nab-based decontamination (susceptibility to contamination, decontamination gain)

Fully interferometric controllable anomalous refraction efficiency using cross modulation with plasmonic metasurfaces.

Science.gov (United States)

Liu, Zhaocheng; Chen, Shuqi; Li, Jianxiong; Cheng, Hua; Li, Zhancheng; Liu, Wenwei; Yu, Ping; Xia, Ji; Tian, Jianguo

2014-12-01

We present a method of fully interferometric, controllable anomalous refraction efficiency by introducing cross-modulated incident light based on plasmonic metasurfaces. Theoretical analyses and numerical simulations indicate that the anomalous and ordinary refracted beams generated from two opposite-helicity incident beams and following the generalized Snell's law will have a superposition for certain incident angles, and the anomalous refraction efficiency can be dynamically controlled by changing the relative phase of the incident sources. As the incident wavelength nears the resonant wavelength of the plasmonic metasurfaces, two equal-amplitude incident beams with opposite helicity can be used to control the anomalous refraction efficiency. Otherwise, two unequal-amplitude incident beams with opposite helicity can be used to fully control the anomalous refraction efficiency. This Letter may offer a further step in the development of controllable anomalous refraction.

Interferometric determination of electron density in a high pressure hydrogen arc. 1. Calculation of refraction index

Energy Technology Data Exchange (ETDEWEB)

Radtke, R; Guenther, K; Ulbricht, R [Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Elektronenphysik

1980-01-14

The refraction index of a hydrogen plasma in LTE was calculated as a function of the wavelength of observation, temperature and pressure, taking into account bound-bound and bound-free transitions of the neutral atom. According to the present calculation, the influence of excited states at higher temperatures is smaller than indicated by Baum et al (Plasma Phys.; 17: 79 (1975)) for argon. Using the calculations presented here, the interferometric investigation of a high pressure hydrogen arc should allow the determination of the electron density with an accuracy of the order of 1%.

Experimental demonstration of interferometric imaging using photonic integrated circuits.

Science.gov (United States)

Su, Tiehui; Scott, Ryan P; Ogden, Chad; Thurman, Samuel T; Kendrick, Richard L; Duncan, Alan; Yu, Runxiang; Yoo, S J B

2017-05-29

This paper reports design, fabrication, and demonstration of a silica photonic integrated circuit (PIC) capable of conducting interferometric imaging with multiple baselines around λ = 1550 nm. The PIC consists of four sets of five waveguides (total of twenty waveguides), each leading to a three-band spectrometer (total of sixty waveguides), after which a tunable Mach-Zehnder interferometer (MZI) constructs interferograms from each pair of the waveguides. A total of thirty sets of interferograms (ten pairs of three spectral bands) is collected by the detector array at the output of the PIC. The optical path difference (OPD) of each interferometer baseline is kept to within 1 µm to maximize the visibility of the interference measurement. We constructed an experiment to utilize the two baselines for complex visibility measurement on a point source and a variable width slit. We used the point source to demonstrate near unity value of the PIC instrumental visibility, and used the variable slit to demonstrate visibility measurement for a simple extended object. The experimental result demonstrates the visibility of baseline 5 and 20 mm for a slit width of 0 to 500 µm in good agreement with theoretical predictions.

Quantum Discord Determines the Interferometric Power of Quantum States

Science.gov (United States)

Girolami, Davide; Souza, Alexandre M.; Giovannetti, Vittorio; Tufarelli, Tommaso; Filgueiras, Jefferson G.; Sarthour, Roberto S.; Soares-Pinto, Diogo O.; Oliveira, Ivan S.; Adesso, Gerardo

2014-05-01

Quantum metrology exploits quantum mechanical laws to improve the precision in estimating technologically relevant parameters such as phase, frequency, or magnetic fields. Probe states are usually tailored to the particular dynamics whose parameters are being estimated. Here we consider a novel framework where quantum estimation is performed in an interferometric configuration, using bipartite probe states prepared when only the spectrum of the generating Hamiltonian is known. We introduce a figure of merit for the scheme, given by the worst-case precision over all suitable Hamiltonians, and prove that it amounts exactly to a computable measure of discord-type quantum correlations for the input probe. We complement our theoretical results with a metrology experiment, realized in a highly controllable room-temperature nuclear magnetic resonance setup, which provides a proof-of-concept demonstration for the usefulness of discord in sensing applications. Discordant probes are shown to guarantee a nonzero phase sensitivity for all the chosen generating Hamiltonians, while classically correlated probes are unable to accomplish the estimation in a worst-case setting. This work establishes a rigorous and direct operational interpretation for general quantum correlations, shedding light on their potential for quantum technology.

Influence of surface position along the working range of conoscopic holography sensors on dimensional verification of AISI 316 wire EDM machined surfaces.

Science.gov (United States)

Fernández, Pedro; Blanco, David; Rico, Carlos; Valiño, Gonzalo; Mateos, Sabino

2014-03-06

Conoscopic holography (CH) is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F) and power (P) until the quality indicators Signal-to-Noise Ratio (SNR) and signal envelope (Total) meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR). Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP) on a CMM.

CubiCal - Fast radio interferometric calibration suite exploiting complex optimisation

Science.gov (United States)

Kenyon, J. S.; Smirnov, O. M.; Grobler, T. L.; Perkins, S. J.

2018-05-01

It has recently been shown that radio interferometric gain calibration can be expressed succinctly in the language of complex optimisation. In addition to providing an elegant framework for further development, it exposes properties of the calibration problem which can be exploited to accelerate traditional non-linear least squares solvers such as Gauss-Newton and Levenberg-Marquardt. We extend existing derivations to chains of Jones terms: products of several gains which model different aberrant effects. In doing so, we find that the useful properties found in the single term case still hold. We also develop several specialised solvers which deal with complex gains parameterised by real values. The newly developed solvers have been implemented in a Python package called CubiCal, which uses a combination of Cython, multiprocessing and shared memory to leverage the power of modern hardware. We apply CubiCal to both simulated and real data, and perform both direction-independent and direction-dependent self-calibration. Finally, we present the results of some rudimentary profiling to show that CubiCal is competitive with respect to existing calibration tools such as MeqTrees.

Broadband interferometric characterisation of nano-positioning stages with sub-10 pm resolution

Science.gov (United States)

Li, Zhi; Brand, Uwe; Wolff, Helmut; Koenders, Ludger; Yacoot, Andrew; Puranto, Prabowo

2017-06-01

A traceable calibration setup for investigation of the quasi-static and the dynamic performance of nano-positioning stages is detailed, which utilizes a differential plane-mirror interferometer with double-pass configuration from the National Physical Laboratory (NPL). An NPL-developed FPGA-based interferometric data acquisition and decoding system has been used to enable traceable quasi-static calibration of nano-positioning stages with high resolution. A lockin based modulation technique is further introduced to quantitatively calibrate the dynamic response of moving stages with a bandwidth up to 100 kHz and picometer resolution. First experimental results have proven that the calibration setup can achieve under nearly open-air conditions a noise floor lower than 10 pm/sqrt(Hz). A pico-positioning stage, that is used for nanoindentation with indentation depths down to a few picometers, has been characterized with this calibration setup.

Simultaneous interferometric measurement of linear coefficient of thermal expansion and temperature-dependent refractive index coefficient of optical materials.

Science.gov (United States)

Corsetti, James A; Green, William E; Ellis, Jonathan D; Schmidt, Greg R; Moore, Duncan T

2016-10-10

Characterizing the thermal properties of optical materials is necessary for understanding how to design an optical system for changing environmental conditions. A method is presented for simultaneously measuring both the linear coefficient of thermal expansion and the temperature-dependent refractive index coefficient of a sample interferometrically in air. Both the design and fabrication of the interferometer is presented as well as a discussion of the results of measuring both a steel and a CaF2 sample.

Theoretical fringe profiles with crossed Babinet compensators in testing concave aspheric surfaces.

Science.gov (United States)

Saxena, A K; Lancelot, J P

1982-11-15

This paper presents the theory for the use of crossed Babinet compensators in testing concave aspheric surfaces. Theoretical fringe profiles for a sphere and for an aspheric surface with primary aberration are shown. Advantages of this method are discussed.

Testing general relativity with the neutral kaon system

International Nuclear Information System (INIS)

Chardin, G.

1992-01-01

The arguments favouring gravitation as the 'Master Arrow of Time' are briefly reviewed and the possibility that CP violation observed in the neutral kaon system may be explained by a violation of the Equivalence Principle is discussed. It was attempted to demonstrate that the arguments against antigravity should be reconsidered and that the neutral kaon system, the most sensitive interferometric system at the disposal, is ideal to test the existence of antigravity. (R.P.) 33 refs

Surface-based test plan, Deaf Smith County, Texas Site: Draft

International Nuclear Information System (INIS)

1985-01-01

The Surface-Based Test Plan (SBTP) is the plan which accounts for all surface-based site field work to be conducted at the Permian salt site selected for characterization. The SBTP relates data needs from program requirement documents and presents plans to satisfy the data needs. The SBTP excludes plans for construction of the Exploratory Shaft Facility (ESF) and plans for the in situ testing. The SBTP is a hierarchical plan stemming from the Technical Program Plan. The SBTP describes in detail the process by which surface-based study plans are defined, developed, and controlled. The plans hierarchy extends downward thru subordinate Site Study Plans (SSPs), which describe in detail elements of field work to be done, to detailed Procedures which document the exact methodologies to be employed in the conduct of field work. The plan is a QA level S document, although some of its elements are at lower QA levels. The plan is a controlled document, and any proposed amendments to the plan or subordinate documents can only be implemented through the specified change control procedure

Code-modulated interferometric imaging system using phased arrays

Science.gov (United States)

Chauhan, Vikas; Greene, Kevin; Floyd, Brian

2016-05-01

Millimeter-wave (mm-wave) imaging provides compelling capabilities for security screening, navigation, and bio- medical applications. Traditional scanned or focal-plane mm-wave imagers are bulky and costly. In contrast, phased-array hardware developed for mass-market wireless communications and automotive radar promise to be extremely low cost. In this work, we present techniques which can allow low-cost phased-array receivers to be reconfigured or re-purposed as interferometric imagers, removing the need for custom hardware and thereby reducing cost. Since traditional phased arrays power combine incoming signals prior to digitization, orthogonal code-modulation is applied to each incoming signal using phase shifters within each front-end and two-bit codes. These code-modulated signals can then be combined and processed coherently through a shared hardware path. Once digitized, visibility functions can be recovered through squaring and code-demultiplexing operations. Pro- vided that codes are selected such that the product of two orthogonal codes is a third unique and orthogonal code, it is possible to demultiplex complex visibility functions directly. As such, the proposed system modulates incoming signals but demodulates desired correlations. In this work, we present the operation of the system, a validation of its operation using behavioral models of a traditional phased array, and a benchmarking of the code-modulated interferometer against traditional interferometer and focal-plane arrays.

Using Response Surface Methods to Correlate the Modal Test of an Inflatable Test Article

Science.gov (United States)

Gupta, Anju

2013-01-01

This paper presents a practical application of response surface methods (RSM) to correlate a finite element model of a structural modal test. The test article is a quasi-cylindrical inflatable structure which primarily consists of a fabric weave, with an internal bladder and metallic bulkheads on either end. To mitigate model size, the fabric weave was simplified by representing it with shell elements. The task at hand is to represent the material behavior of the weave. The success of the model correlation is measured by comparing the four major modal frequencies of the analysis model to the four major modal frequencies of the test article. Given that only individual strap material properties were provided and material properties of the overall weave were not available, defining the material properties of the finite element model became very complex. First it was necessary to determine which material properties (modulus of elasticity in the hoop and longitudinal directions, shear modulus, Poisson's ratio, etc.) affected the modal frequencies. Then a Latin Hypercube of the parameter space was created to form an efficiently distributed finite case set. Each case was then analyzed with the results input into RSM. In the resulting response surface it was possible to see how each material parameter affected the modal frequencies of the analysis model. If the modal frequencies of the analysis model and its corresponding parameters match the test with acceptable accuracy, it can be said that the model correlation is successful.

Quadrature Errors and DC Offsets Calibration of Analog Complex Cross-Correlator for Interferometric Passive Millimeter-Wave Imaging Applications

Directory of Open Access Journals (Sweden)

Chao Wang

2018-02-01

Full Text Available The design and calibration of the cross-correlator are crucial issues for interferometric imaging systems. In this paper, an analog complex cross-correlator with output DC offsets and amplitudes calibration capability is proposed for interferometric passive millimeter-wave security sensing applications. By employing digital potentiometers in the low frequency amplification circuits of the correlator, the outputs characteristics of the correlator could be digitally controlled. A measurement system and a corresponding calibration scheme were developed in order to eliminate the output DC offsets and the quadrature amplitude error between the in-phase and the quadrature correlating subunits of the complex correlator. By using vector modulators to provide phase controllable correlated noise signals, the measurement system was capable of obtaining the output correlation circle of the correlator. When injected with −18 dBm correlated noise signals, the calibrated quadrature amplitude error was 0.041 dB and the calibrated DC offsets were under 26 mV, which was only 7.1% of the uncalibrated value. Furthermore, we also described a quadrature errors calibration algorithm in order to estimate the quadrature phase error and in order to improve the output phase accuracy of the correlator. After applying this calibration, we were able to reduce the output phase error of the correlator to 0.3°.

Virtual-stereo fringe reflection technique for specular free-form surface testing

Science.gov (United States)

Ma, Suodong; Li, Bo

2016-11-01

Due to their excellent ability to improve the performance of optical systems, free-form optics have attracted extensive interest in many fields, e.g. optical design of astronomical telescopes, laser beam expanders, spectral imagers, etc. However, compared with traditional simple ones, testing for such kind of optics is usually more complex and difficult which has been being a big barrier for the manufacture and the application of these optics. Fortunately, owing to the rapid development of electronic devices and computer vision technology, fringe reflection technique (FRT) with advantages of simple system structure, high measurement accuracy and large dynamic range is becoming a powerful tool for specular free-form surface testing. In order to obtain absolute surface shape distributions of test objects, two or more cameras are often required in the conventional FRT which makes the system structure more complex and the measurement cost much higher. Furthermore, high precision synchronization between each camera is also a troublesome issue. To overcome the aforementioned drawback, a virtual-stereo FRT for specular free-form surface testing is put forward in this paper. It is able to achieve absolute profiles with the help of only one single biprism and a camera meanwhile avoiding the problems of stereo FRT based on binocular or multi-ocular cameras. Preliminary experimental results demonstrate the feasibility of the proposed technique.

Standard Specification for Steel Blades Used with the Photovoltaic Module Surface Cut Test

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This specification specifies the recommended physical characteristics of the steel blades required for the surface cut test described in ANSI/UL 1703 (Section 24) and IEC 61730-2 (Paragraph 10.3). 1.2 ANSI/UL 1703 and IEC 61730-2 are standards for photovoltaic module safety testing. 1.3 This standard provides additional fabrication details for the surface cut test blades that are not provided in ANSI/UL 1703 or IEC 61730-2. Surface cut test blades that have out-of-tolerance corner radii or burrs are known to cause erroneous test results, either passes or failures. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Scalable Top-Down Approach Tailored by Interferometric Lithography to Achieve Large-Area Single-Mode GaN Nanowire Laser Arrays on Sapphire Substrate.

Science.gov (United States)

Behzadirad, Mahmoud; Nami, Mohsen; Wostbrock, Neal; Zamani Kouhpanji, Mohammad Reza; Feezell, Daniel F; Brueck, Steven R J; Busani, Tito

2018-03-27

GaN nanowires are promising for optical and optoelectronic applications because of their waveguiding properties and large optical band gap. However, developing a precise, scalable, and cost-effective fabrication method with a high degree of controllability to obtain high-aspect-ratio nanowires with high optical properties and minimum crystal defects remains a challenge. Here, we present a scalable two-step top-down approach using interferometric lithography, for which parameters can be controlled precisely to achieve highly ordered arrays of nanowires with excellent quality and desired aspect ratios. The wet-etch mechanism is investigated, and the etch rates of m-planes {11̅00} (sidewalls) were measured to be 2.5 to 70 nm/h depending on the Si doping concentration. Using this method, uniform nanowire arrays were achieved over a large area (>10 5 μm 2 ) with an spect ratio as large as 50, a radius as small as 17 nm, and atomic-scale sidewall roughness (top-down approach using interferometric lithography and is promising for fabrication of III-nitride-based nanophotonic devices (radial/axial) on the original substrate.

Measuring the Impact of Wildfire on Active Layer Thickness in a Discontinuous Permafrost region using Interferometric Synthetic Aperture Radar (InSAR)

Science.gov (United States)

Michaelides, R. J.; Schaefer, K. M.; Zebker, H. A.; Liu, L.; Chen, J.; Parsekian, A.

2017-12-01

In permafrost regions, the active layer is defined as the uppermost portion of the permafrost table that is subject to annual freeze/thaw cycles. The active layer plays a crucial role in surface processes, surface hydrology, and vegetation succession; furthermore, trapped methane, carbon dioxide, and other greenhouse gases in permafrost are released into the atmosphere as permafrost thaws. A detailed understanding of active layer dynamics is therefore critical towards understanding the interactions between permafrost surface processes, freeze/thaw cycles, and climate-especially in regions across the Arctic subject to long-term permafrost degradation. The Yukon-Kuskokwim (YK) delta in southwestern Alaska is a region of discontinuous permafrost characterized by surface lakes, wetlands, and thermokarst depressions. Furthermore, extensive wildfires have burned across the YK delta in 2006, 2007, and 2015, impacting vegetation cover, surface soil moisture, and the active layer. Using data from the ALOS PALSAR, ALOS-2 PALSAR-2, and Sentinel-1A/B space borne synthetic aperture radar (SAR) systems, we generate a series of interferograms over a study site in the YK delta spanning 2007-2011, and 2014-present. Using the ReSALT (Remotely-Sensed Active Layer Thickness) technique, we demonstrate that active layer can be characterized over most of the site from the relative interferometric phase difference due to ground subsidence and rebound associated with the seasonal active layer freeze/thaw cycle. Additionally, we show that this technique successfully discriminates between burned and unburned regions, and can resolve increases in active layer thickness in burned regions on the order of 10's of cms. We use the time series of interferograms to discuss permafrost recovery following wildfire burn, and compare our InSAR observations with GPR and active layer probing data from a 2016 summer field campaign to the study site. Finally, we compare the advantages and disadvantages of

Measurement of morphing wing deflection by a cross-coherence fiber optic interferometric technique

Science.gov (United States)

Tomić, Miloš C.; Djinović, Zoran V.; Scheerer, Michael; Petricevic, Slobodan J.

2018-01-01

A fiber-optic interferometric technique aimed at measuring the deflection of aircrafts’ morphing wings is presented. The wing deflection induces a strain in the sensing fiber optic coils that are firmly fixed onto the wing. A change of the phase angle of the light propagating through the fiber is measured by an ‘all-in-fiber’ Michelson interferometer based on a 3 × 3 fiber-optic coupler. Two light sources of different coherence lengths and wavelengths are simultaneously used to ensure a wide measurement range and high accuracy. A new technique for determination of the zero deflection point using the cross-correlation of the two interferograms is proposed. The experiments performed on a specimen made of a carbon-fiber-reinforced plastic honeycomb structure demonstrated a relative uncertainty morphing wing deflection.

Spatial Frequency Multiplexing of Fiber-Optic Interferometric Refractive Index Sensors Based on Graded-Index Multimode Fibers

Science.gov (United States)

Liu, Li; Gong, Yuan; Wu, Yu; Zhao, Tian; Wu, Hui-Juan; Rao, Yun-Jiang

2012-01-01

Fiber-optic interferometric sensors based on graded-index multimode fibers have very high refractive-index sensitivity, as we previously demonstrated. In this paper, spatial-frequency multiplexing of this type of fiber-optic refractive index sensors is investigated. It is estimated that multiplexing of more than 10 such sensors is possible. In the multiplexing scheme, one of the sensors is used to investigate the refractive index and temperature responses. The fast Fourier transform (FFT) of the combined reflective spectra is analyzed. The intensity of the FFT spectra is linearly related with the refractive index and is not sensitive to the temperature.

Mapping three-dimensional surface deformation by combining multiple-aperture interferometry and conventional interferometry: Application to the June 2007 eruption of Kilauea Volcano, Hawaii

Science.gov (United States)

Jung, H.-S.; Lu, Z.; Won, J.-S.; Poland, Michael P.; Miklius, Asta

2011-01-01

Surface deformation caused by an intrusion and small eruption during June 17-19, 2007, along the East Rift Zone of Kilauea Volcano, Hawaii, was three-dimensionally reconstructed from radar interferograms acquired by the Advanced Land Observing Satellite (ALOS) phased-array type L-band synthetic aperture radar (SAR) (PALSAR) instrument. To retrieve the 3-D surface deformation, a method that combines multiple-aperture interferometry (MAI) and conventional interferometric SAR (InSAR) techniques was applied to one ascending and one descending ALOS PALSAR interferometric pair. The maximum displacements as a result of the intrusion and eruption are about 0.8, 2, and 0.7 m in the east, north, and up components, respectively. The radar-measured 3-D surface deformation agrees with GPS data from 24 sites on the volcano, and the root-mean-square errors in the east, north, and up components of the displacement are 1.6, 3.6, and 2.1 cm, respectively. Since a horizontal deformation of more than 1 m was dominantly in the north-northwest-south-southeast direction, a significant improvement of the north-south component measurement was achieved by the inclusion of MAI measurements that can reach a standard deviation of 3.6 cm. A 3-D deformation reconstruction through the combination of conventional InSAR and MAI will allow for better modeling, and hence, a more comprehensive understanding, of the source geometry associated with volcanic, seismic, and other processes that are manifested by surface deformation.

Delay/Disruption Tolerant Networks (DTN): Testing and Demonstration for Lunar Surface Applications

Science.gov (United States)

2009-01-01

This slide presentation reviews the testing of the Delay/Disruption Tolerant Network (DTN) designed for use with Lunar Surface applications. This is being done through the DTN experimental Network (DEN), that permit access and testing by other NASA centers, DTN team members and protocol developers. The objective of this work is to demonstrate DTN for high return applications in lunar scenarios, provide DEN connectivity with analogs of Constellation elements, emulators, and other resources from DTN Team Members, serve as a wireless communications staging ground for remote analog excursions and enable testing of detailed communication scenarios and evaluation of network performance. Three scenarios for DTN on the Lunar surface are reviewed: Motion imagery, Voice and sensor telemetry, and Navigation telemetry.

Non-Contact Surface Roughness Measurement by Implementation of a Spatial Light Modulator

Directory of Open Access Journals (Sweden)

Laura Aulbach

2017-03-01

Full Text Available The surface structure, especially the roughness, has a significant influence on numerous parameters, such as friction and wear, and therefore estimates the quality of technical systems. In the last decades, a broad variety of surface roughness measurement methods were developed. A destructive measurement procedure or the lack of feasibility of online monitoring are the crucial drawbacks of most of these methods. This article proposes a new non-contact method for measuring the surface roughness that is straightforward to implement and easy to extend to online monitoring processes. The key element is a liquid-crystal-based spatial light modulator, integrated in an interferometric setup. By varying the imprinted phase of the modulator, a correlation between the imprinted phase and the fringe visibility of an interferogram is measured, and the surface roughness can be derived. This paper presents the theoretical approach of the method and first simulation and experimental results for a set of surface roughnesses. The experimental results are compared with values obtained by an atomic force microscope and a stylus profiler.

Surface inspection technique with an eddy current testing array probe

International Nuclear Information System (INIS)

Nishimizu, Akira; Endo, Hisashi; Tooma, Masahiro; Otani, Kenichi; Ouchi, Hirofumi; Yoshida, Isao; Nonaka, Yoshio

2010-01-01

An eddy current testing (ECT) system has been developed for inspecting weld surfaces of components in the reactor pressure vessel of nuclear plants. The system can be applied to curved surfaces with an ECT array probe, it can discriminate flaws from other signal factors by using a combination of arrayed coils signal-phase. The system is applied to a mock-up of core internal components and the signal discrimination using the signal-phase clearly separated flaw and noise signals. (author)

New perspectives in hydrodynamic radial polishing techniques for optical surfaces

Science.gov (United States)

Ruiz, Elfego; Sohn, Erika; Luna, Esteban; Salas, Luis; Cordero, Alberto; González, Jorge; Núñez, Manuel; Salinas, Javier; Cruz-González, Irene; Valdés, Jorge; Cabrera, Victor; Martínez, Benjamín

2004-09-01

In order to overcome classic polishing techniques, a novel hydrodynamic radial polishing tool (HyDRa) is presented; it is useful for the corrective lapping and fine polishing of diverse materials by means of a low-cost abrasive flux and a hydrostatic suspension system that avoids contact of the tool with the working surface. This tool enables the work on flat or curved surfaces of currently up to two and a half meters in diameter. It has the advantage of avoiding fallen edges during the polishing process as well as reducing tool wear out and deformation. The functioning principle is based on the generation of a high-velocity, high-pressure, abrasive emulsion flux with radial geometry. The polishing process is repeatable by means of the control of the tool operational parameters, achieving high degrees of precision and accuracy on optical and semiconductor surfaces, with removal rates of up to 9 mm3/hour and promising excellent surface polishing qualities. An additional advantage of this new tool is the possibility to perform interferometric measurements during the polishing process without the need of dismounting the working surface. A series of advantages of this method, numerical simulations and experimental results are described.

Influence of Surface Position along the Working Range of Conoscopic Holography Sensors on Dimensional Verification of AISI 316 Wire EDM Machined Surfaces

Directory of Open Access Journals (Sweden)

Pedro Fernández

2014-03-01

Full Text Available Conoscopic holography (CH is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F and power (P until the quality indicators Signal-to-Noise Ratio (SNR and signal envelope (Total meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR. Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP on a CMM.

Technology developments for ACIGA high power test facility for advanced interferometry

Energy Technology Data Exchange (ETDEWEB)

Barriga, P [School of Physics, University of Western Australia, Perth, WA 6009 (Australia); Barton, M [California Institute of Technology, LIGO Project, Pasadena, CA 91125 (United States); Blair, D G [School of Physics, University of Western Australia, Perth, WA 6009 (Australia)] [and others

2005-05-21

The High Optical Power Test Facility for Advanced Interferometry has been built by the Australian Consortium for Interferometric Gravitational Astronomy north of Perth in Western Australia. An 80 m suspended cavity has been prepared in collaboration with LIGO, where a set of experiments to test suspension control and thermal compensation will soon take place. Future experiments will investigate radiation pressure instabilities and optical spring effects in a high power optical cavity with {approx}200 kW circulating power. The facility combines research and development undertaken by all consortium members, whose latest results are presented.

Technology developments for ACIGA high power test facility for advanced interferometry

International Nuclear Information System (INIS)

Barriga, P; Barton, M; Blair, D G

2005-01-01

The High Optical Power Test Facility for Advanced Interferometry has been built by the Australian Consortium for Interferometric Gravitational Astronomy north of Perth in Western Australia. An 80 m suspended cavity has been prepared in collaboration with LIGO, where a set of experiments to test suspension control and thermal compensation will soon take place. Future experiments will investigate radiation pressure instabilities and optical spring effects in a high power optical cavity with ∼200 kW circulating power. The facility combines research and development undertaken by all consortium members, whose latest results are presented

Standard test method for damage to contacting solid surfaces under fretting conditions

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This test method covers the studying or ranking the susceptibility of candidate materials to fretting corrosion or fretting wear for the purposes of material selection for applications where fretting corrosion or fretting wear can limit serviceability. 1.2 This test method uses a tribological bench test apparatus with a mechanism or device that will produce the necessary relative motion between a contacting hemispherical rider and a flat counterface. The rider is pressed against the flat counterface with a loading mass. The test method is intended for use in room temperature air, but future editions could include fretting in the presence of lubricants or other environments. 1.3 The purpose of this test method is to rub two solid surfaces together under controlled fretting conditions and to quantify the damage to both surfaces in units of volume loss for the test method. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5...

Radiation flaw detector for testing non-uniform surface bodies of revolution

International Nuclear Information System (INIS)

Valevich, M.I.

1984-01-01

Radiation flaw detector for testing bodies of revolution with non-uniform surface, welded joints, etc., based on spatial filtration and differentiation of ionizing radiation flux has been described. The calculation of the most important unit of flaw detector - integrators - is made. Experimental studies of the sensitivity have shown, that the radiation flaw detector can be used for rapid testing of products with the sensitivity comparable with the sensitivity of radiographic testing of steel

The wire optical test: a thorough analytical study in and out of caustic surface, and advantages of a dynamical adaptation

Science.gov (United States)

Alejandro Juárez-Reyes, Salvador; Sosa-Sánchez, Citlalli Teresa; Silva-Ortigoza, Gilberto; de Jesús Cabrera-Rosas, Omar; Espíndola-Ramos, Ernesto; Ortega-Vidals, Paula

2018-03-01

Among the best known non-interferometric optical tests are the wire test, the Foucault test and Ronchi test with a low frequency grating. Since the wire test is the seed to understand the other ones, the aim of the present work is to do a thorough study of this test for a lens with symmetry of revolution and to do this study for any configuration of the object and detection planes where both planes could intersect: two, one or no branches of the caustic region (including the marginal and paraxial foci). To this end, we calculated the vectorial representation for the caustic region, and we found the analytical expression for the pattern; we report that the analytical pattern explicitly depends on the magnitude of a branch of the caustic. With the analytical pattern we computed a set of simulations of a dynamical adaptation of the optical wire test. From those simulations, we have done a thorough analysis of the topological structure of the pattern; so we explain how the multiple image formation process and the image collapse process take place for each configuration, in particular, when both the wire and the detection planes are placed inside the caustic region, which has not been studied before. For the first time, we remark that not only the intersections of the object and detection planes with the caustic are important in the change of pattern topology; but also the projection of the intersection between the caustic and the object plane mapped onto the detection plane; and the virtual projection of the intersection between the caustic and the detection plane mapped onto the object plane. We present that for the new configurations of the optical system, the wire image is curves of the Tschirnhausen’s cubic, the piriform and the deformed eight-curve types.

Biointrusion test plan for the Permanent Isolation Surface Barrier Prototype

International Nuclear Information System (INIS)

Link, S.O.; Cadwell, L.L.; Brandt, C.A.; Downs, J.L.; Rossi, R.E.; Gee, G.W.

1994-04-01

This document provides a testing and monitoring plan for the biological component of the prototype barrier slated for construction at the Hanford Site. The prototype barrier is an aboveground structure engineered to demonstrate the basic features of an earthen cover system. It is designed to permanently isolate waste from the biosphere. The features of the barrier include multiple layers of soil and rock materials and a low-permeability asphalt sublayer. The surface of the barrier consists of silt loam soil, covered with plants. The barrier sides are reinforced with rock or coarse earthen-fill to protect against wind and water erosion. The sublayers inhibit plant and animal intrusion and percolation of water. A series of tests will be conducted on the prototype barrier over the next several years to evaluate barrier performance under extreme climatic conditions. Plants and animals will play a significant role in the hydrologic and water and wind erosion characteristics of the prototype barrier. Studies on the biological component of the prototype barrier will include work on the initial revegetation of the surface, continued monitoring of the developing plant community, rooting depth and dispersion in the context of biointrusion potential, the role of plants in the hydrology of the surface and toe regions of the barrier, the role of plants in stabilizing the surface against water and wind erosion, and the role of burrowing animals in the hydrology and water and wind erosion of the barrier

A new free-surface stabilization algorithm for geodynamical modelling: Theory and numerical tests

Science.gov (United States)

Andrés-Martínez, Miguel; Morgan, Jason P.; Pérez-Gussinyé, Marta; Rüpke, Lars

2015-09-01

The surface of the solid Earth is effectively stress free in its subaerial portions, and hydrostatic beneath the oceans. Unfortunately, this type of boundary condition is difficult to treat computationally, and for computational convenience, numerical models have often used simpler approximations that do not involve a normal stress-loaded, shear-stress free top surface that is free to move. Viscous flow models with a computational free surface typically confront stability problems when the time step is bigger than the viscous relaxation time. The small time step required for stability (develop strategies that mitigate the stability problem by making larger (at least ∼10 Kyr) time steps stable and accurate. Here we present a new free-surface stabilization algorithm for finite element codes which solves the stability problem by adding to the Stokes formulation an intrinsic penalization term equivalent to a portion of the future load at the surface nodes. Our algorithm is straightforward to implement and can be used with both Eulerian or Lagrangian grids. It includes α and β parameters to respectively control both the vertical and the horizontal slope-dependent penalization terms, and uses Uzawa-like iterations to solve the resulting system at a cost comparable to a non-stress free surface formulation. Four tests were carried out in order to study the accuracy and the stability of the algorithm: (1) a decaying first-order sinusoidal topography test, (2) a decaying high-order sinusoidal topography test, (3) a Rayleigh-Taylor instability test, and (4) a steep-slope test. For these tests, we investigate which α and β parameters give the best results in terms of both accuracy and stability. We also compare the accuracy and the stability of our algorithm with a similar implicit approach recently developed by Kaus et al. (2010). We find that our algorithm is slightly more accurate and stable for steep slopes, and also conclude that, for longer time steps, the optimal

Spatially Extended and High-Velocity Dispersion Molecular Component in Spiral Galaxies: Single-Dish Versus Interferometric Observations

Science.gov (United States)

Caldú-Primo, Anahi; Schruba, Andreas; Walter, Fabian; Leroy, Adam; Bolatto, Alberto D.; Vogel, Stuart

2015-02-01

Recent studies of the molecular medium in nearby galaxies have provided mounting evidence that the molecular gas can exist in two phases: one that is clumpy and organized as molecular clouds and another one that is more diffuse. This last component has a higher velocity dispersion than the clumpy one. In order to investigate these two molecular components further, we compare the fluxes and line widths of CO in NGC 4736 and NGC 5055, two nearby spiral galaxies for which high-quality interferometric as well as single-dish data sets are available. Our analysis leads to two main results: (1) employing three different methods, we determine the flux recovery of the interferometer as compared to the single-dish to be within a range of 35%-74% for NGC 4736 and 81%-92% for NGC 5055, and (2) when focusing on high (S/N ≥ 5) lines of sight (LOSs), the single-dish line widths are larger by ˜(40 ± 20)% than the ones derived from interferometric data, which is in agreement with stacking all LOSs. These results point to a molecular gas component that is distributed over spatial scales larger than 30″(˜1 kpc), and is therefore filtered out by the interferometer. The available observations do not allow us to distinguish between a truly diffuse gas morphology and a uniform distribution of small clouds that are separated by less than the synthesized beam size (˜3″ or ˜100 pc), as they would both be invisible for the interferometer. This high velocity dispersion component has a dispersion similar to what is found in the atomic medium, as traced through observations of the H i line.

Preliminary test of two stump surface protectants against Fomes annosus.

Science.gov (United States)

E.E. Nelson; C.Y. Li

1980-01-01

Two materials, monolaurin (at two concentrations) and an unidentified species of the genus Streptomyces, were tested along with borax for ability to protect freshly cut stump surfaces of western hemlock (Tsuga heterophylla (Raf.) Sarg.) from colonization by Fomes annosus. Protectants were significantly (P...

Status and plans for future generations of ground-based interferometric gravitational wave antennas

International Nuclear Information System (INIS)

Kawamura, Seiji

2003-01-01

Several medium- to large-scale ground-based interferometric gravitational-wave antennas have been constructed around the world. Although these antennas of the first generation could detect gravitational waves within a few years, it is necessary to improve the sensitivity of the detectors significantly with advanced technologies to ensure more frequent detection of gravitational waves. Stronger seismic isolation and reduction of thermal noise, especially using cryogenic mirrors, are among the most important technologies that can lead us to the realization of advanced detectors. Some of the advanced technologies are already implemented in some of the existing detectors and others are currently being investigated for the future-generation detectors such as advanced LIGO, LCGT, upgrade of GEO600, AIGO, and EURO. We expect that such advanced detectors will eventually open a new window to the universe and establish a new field, 'gravitational wave astronomy'

The design and evaluation of a selectively modulated interferometric dispersive spectrometer

International Nuclear Information System (INIS)

Fitzgerald, J.J.

1986-01-01

In approaching the problem of rapid simultaneous multielement analysis, the large light gathering power, wide spectral range and high resolution of a Fourier Transform Spectrometer (FTS) should be of benefit. The severe mechanical tolerances required in the construction and operation of a classical Michelson interferometer for use in the UV-Visible spectral region have limited investigations in the application of simultaneous trace quantitative analysis. Theory is presented demonstrating that replacement of the fixed mirror in one arm of the Michelson interferometer with a rotating grating preserves most of the FTS advantages and results in a greatly simplified detector system. No mathematical Fourier transform is required. The need for a computer is eliminated. An instrument, SEMIDS (Selectively Modulated Interferometric Dispersive Spectrometer), was constructed to investigate the mathematical model. Design criteria and basic operational performance as a flame emission spectrometer are presented. SEMIDS achieved high resolution, high throughput and greatly simplified operation compared to a Michelson interferometer. Performance as a trace quantitative tool was disappoint because of unanticipated noise contributions from flame background. A summary of the noise component contributions is discussed

Model tests for corrosion influence of electrode surface on electroosmosis in marine sludge

Science.gov (United States)

Zheng, Lingwei; Li, Jinzhu; Shi, Hanru

2017-11-01

The corrosion of metal electrodes is inevitable on electroosmosis in soil. Surface corrosion of electrodes is also one of the reasons for increasing energy consumption in electroosmosis treatment. A series of laboratory tests were conducted employing three kinds of materials, aluminium, steel, and brass. To explore the impact of surface corrosion degree on electroosmosis, metal electrodes were pretreated with durations 0 h, 12 h, 24 h, and 36 h. After the pretreatment, corroded electrodes are used as anodes on electroosmosis. Water discharge, current, voltage potential were measured during the tests; water content was also tested at three points after the electroosmosis. The results showed that aluminium was better than steel in electroosmotic drainage while brass provided the worst dewatering performance. Surface corrosion did not influence the aluminium and steel on electroosmosis in marine sludge, but brass did. In the pretreatment of brass electrodes, corrosion rate had started to slow down at later periods, with the deterioration rate of dewatering reduced afterwards. As the results showed, it is not recommended to employ those easily deteriorated electrode materials from surface corrosion in practical engineering, such as brass; electrode material with higher electroosmosis exchange rate is recommended, such as aluminium.

A study of cooling time reduction of interferometric cryogenic gravitational wave detectors using a high-emissivity coating

Energy Technology Data Exchange (ETDEWEB)

Sakakibara, Y.; Yamamoto, K.; Chen, D.; Tokoku, C.; Uchiyama, T.; Ohashi, M.; Kuroda, K. [Institute for Cosmic Ray Research (ICRR), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Kimura, N.; Suzuki, T.; Koike, S. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2014-01-29

In interferometric cryogenic gravitational wave detectors, there are plans to cool mirrors and their suspension systems (payloads) in order to reduce thermal noise, that is, one of the fundamental noise sources. Because of the large payload masses (several hundred kg in total) and their thermal isolation, a cooling time of several months is required. Our calculation shows that a high-emissivity coating (e.g. a diamond-like carbon (DLC) coating) can reduce the cooling time effectively by enhancing radiation heat transfer. Here, we have experimentally verified the effect of the DLC coating on the reduction of the cooling time.

Nanoporous Zeolite Thin Film-Based Fiber Intrinsic Fabry-Perot Interferometric Sensor for Detection of Dissolved Organics in Water

Directory of Open Access Journals (Sweden)

Hai Xiao

2006-08-01

Full Text Available A fiber optic intrinsic Fabry-Perot interferometric (IFPI chemical sensor wasdeveloped by fine-polishing a thin layer of polycrystalline nanoporous MFI zeolitesynthesized on the cleaved endface of a single mode fiber. The sensor operated bymonitoring the optical thickness changes of the zeolite thin film caused by the adsorption oforganic molecules into the zeolite channels. The optical thickness of the zeolite thin filmwas measured by white light interferometry. Using methanol, 2-propanol, and toluene as themodel chemicals, it was demonstrated that the zeolite IPFI sensor could detect dissolvedorganics in water with high sensitivity.

Fiber tests on a radiotelescope.

Science.gov (United States)

Connes, P.; Reynaud, F.

In order to demonstrate use of fibers in a future radio-dish-mounted interferometric array or optical telescopes, two 100-m SM fibers were installed on the Nançay radiotelescope, used in a serendipitous mode. They formed the two arms of a Mach-Zehnder interferometer, illuminated by a 6328 Å laser. Thermal and interferometric servo-control were simultaneously applied. Even under severe conditions, path difference was maintained stable to within a few Å.This is considerably better than needed for any ground-based application, and still more than adequate for a roughly-similar proposed space-borne device. Some more fiber problems remain to be solved.

Characterization of holding brake friction pad surface after pin-on-plate wear test

Science.gov (United States)

Drago, N.; Gonzalez Madruga, D.; De Chiffre, L.

2018-03-01

This article concerns the metrological characterization of the surface on a holding brake friction material pin after a pin-on-plate (POP) wear test. The POP test induces the formation of surface plateaus that affect brake performances such as wear, friction, noise and heat. Three different materials’ surfaces have been characterized after wear from data obtained with a focus variation 3D microscope. A new surface characterization approach with plateau identification is proposed, using the number of plateau on the surface, equivalent diameter, length and breadth as measurands. The identification method is based on determining and imposing ISO 27158-2 lower plateau limit (LPL) in material probability curves; and on applying a combined criterion of height segmentation threshold and equivalent diameter threshold. The method determines the criterion thresholds for each material since LPL appears typical by material. The proposed method has allowed quantifying the surface topography at two different levels of wear. An expanded measurement uncertainty of 3.5 µm for plateau dimensions in the range 50–2000 µm and one of 0.15 µm for plateau heights up to 10 µm have been documented.

Field Measurements of PCB emissions from Building Surfaces Using a New Portable Emission Test Cell

DEFF Research Database (Denmark)

Lyng, Nadja; Haven, Rune; Gunnarsen, Lars Bo

2016-01-01

The purpose of the study was to measure PCB-emission rates from indoor surfaces on-site in contaminated buildings using a newly developed portable emission test cell. Emission rates were measured from six different surfaces; three untreated surfaces and three remediated surfaces in a contaminated...

A new design of the LAPS land surface scheme for use over and through heterogeneous and non-heterogeneous surfaces: Numerical simulations and tests

Science.gov (United States)

Mihailovic, Dragutin T.; Lazic, Jelena; Leśny, Jacek; Olejnik, Janusz; Lalic, Branislava; Kapor, Darko; Cirisan, Ana

2010-05-01

Numerical simulations and tests with the recently redesigned land-air parameterization scheme (LAPS) are presented. In all experiments, supported either by one-point micrometeorological, 1D or 3D simulations, the attention has been directed to: (1) comparison of simulation outputs, expressing the energy transfer over and through heterogeneous and non-heterogeneous surfaces, versus observations and (2) analysis of uncertainties occurring in the solution of the energy balance equation at the land-air interface. To check the proposed method for aggregation of albedo, "propagating hole" sensitivity tests with LAPS over a sandstone rock grid cell have been performed with the forcing meteorological data for July 17, 1999 in Baxter site, Philadelphia (USA). Micrometeorological and biophysical measurements from the surface experiments conducted over crops and apple orchard in Serbia, Poland, Austria and France were used to test the operation of LAPS in calculating surface fluxes and canopy environment temperatures within and above plant covers of different densities. In addition, sensitivity tests with single canopy covers over the Central Europe region and comparison against the observations taken from SYNOP data using 3D simulations were made. Validation of LAPS performances over a solid surface has been done by comparison of 2 m air temperature observations against 5-day simulations over the Sahara Desert rocky ground using 3D model. To examine how realistically the LAPS simulates surface processes over a heterogeneous surface, we compared the air temperature measured at 2 m and that predicted by the 1D model with the LAPS as the surface scheme. Finally, the scheme behaviour over urban surface was tested by runs over different parts of a hypothetical urban area. The corresponding 1D simulations were carried out with an imposed meteorological dataset collected during HAPEX-MOBILHY experiment at Caumont (France). The quantities predicted by the LAPS compare well with the

Uncertainty considerations for interferometric stability testing

NARCIS (Netherlands)

Ellis, J.D.; Joo, K.N.; Verlaan, A.L.; Spronck, J.W.

2008-01-01

Material stability is an important parameter for EUV lithography, space instrumentation, and metrology in general. In both EUV lithography and space, more information is needed about material stability during an atmospheric to vacuum transition. For metrology instruments in general, determining the

Neutron interferometric tests of quantum mechanics

International Nuclear Information System (INIS)

Rauch, H.

1986-01-01

Since the invention of perfect crystal neutron interferometry this technique has become an important tool in the realization of many textbook experiments in quantum mechanics. Widely separated coherent beams of thermal neutrons are produced and superposed by dynamical Bragg diffraction from a properly shaped perfect crystal. The observed interference patterns show the characteristic coherence properties of matter waves which are influenced by the individual particle and by the properties of the experimental device. The verification of the 4π-periodicity of spinor wavefunctions and the realization of the spin-superposition experiment on a macroscopic scale has become feasible by this technique. A new kind of a quantum beat effect with an energy sensitivity of 2.7 x 20 19 eV has been observed in a double coil resonance experiment. The influence of gravity and of the Earth's rotation on the wavefunction become visible at a level of an elementary particle with non-zero mass. All the results are in agreement with the formulation of quantum mechanics but, nevertheless, they stimulate discussion about its interpretation. The particle-wave dualism becomes obvious on a macroscopic scale and with a beam of massive particles. (author)

Mechanical Q-factor measurements on a test mass with a structured surface

Energy Technology Data Exchange (ETDEWEB)

Nawrodt, R [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Zimmer, A [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Koettig, T [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Clausnitzer, T [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Bunkowski, A [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Kley, E B [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Schnabel, R [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Danzmann, K [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Nietzsche, S [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Vodel, W [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Tuennermann, A [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Seidel, P [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany)

2007-07-15

We present mechanical Q-factors (quality factors) of a crystalline quartz test mass with a nano-structured surface, measured in the temperature regime from 5 to 300 K. The nano-structure was a grating with a period of 2 {mu}m and a depth of about 0.1 {mu}m. Comparative measurements were performed on the plain substrate and on the structured test mass with different numbers of SiO{sub 2}/Ta{sub 2}O{sub 5} coating layers. The measurements at different stages of the test mass fabrication process show that the surface distortion induced by the nanostructure does not severely lower the mechanical Q-factor of the substrate. Damping due to a multi-layer coating stack was found to be orders of magnitude higher. The results provide vital information concerning the potential usage of low-thermal noise nano-structured test masses in future generations of high-precision laser interferometers and in current attempts to measure quantum effects of macroscopic mirror oscillators.

False-positive result when a diphenylcarbazide spot test is used on trivalent chromium-passivated zinc surfaces

DEFF Research Database (Denmark)

Reveko, Valeriia; Lampert, Felix; Din, Rameez Ud

2018-01-01

chromium passivation on zinc; however, subsequent analysis by XPS could not confirm the presence of chromium in a hexavalent state. Conclusions Unintended oxidation of DPC induced by atmospheric corrosion is suggested as a possible reason for the false-positive reaction of the DPC test on a trivalent......A colorimetric 1,5-diphenylcarbazide (DPC)-based spot test can be used to identify hexavalent chromium on various metallic and leather surfaces. DPC testing on trivalent chromium-passivated zinc surfaces has unexpectedly given positive results in some cases, apparently indicating the presence...... of hexavalent chromium; however, the presence of hexavalent chromium has never been confirmed with more sensitive and accurate test methods. Objectives To examine the presence of hexavalent chromium on trivalent chromium-passivated zinc surfaces with a DPC-based spot test. Methods A colorimetric DPC spot test...

CENTRAL WAVELENGTH ADJUSTMENT OF LIGHT EMITTING SOURCE IN INTERFEROMETRIC SENSORS BASED ON FIBER-OPTIC BRAGG GRATINGS

Directory of Open Access Journals (Sweden)

A. S. Aleynik

2015-09-01

Full Text Available The paper is focused on the investigation of fiber-optic interferometric sensor based on the array of fiber Bragg gratings. Reflection spectra displacement mechanism of the fiber Bragg gratings under the external temperature effects and the static pressure is described. The experiment has shown that reflection spectra displacement of Bragg gratings reduces the visibility of the interference pattern. A method of center wavelength adjustment is proposed for the optical radiation source in accord ance with the current Bragg gratings reflection spectra based on the impulse relative modulation of control signal for the Peltier element controller. The semiconductor vertical-cavity surface-emitting laser controlled by a pump driver is used as a light source. The method is implemented by the Peltier element controller regulating and stabilizing the light source temperature, and a programmable logic-integrated circuit monitoring the Peltier element controller. The experiment has proved that the proposed method rendered possible to regulate the light source temperature at a pitch of 0.05 K and adjust the optical radiation source center wavelength at a pitch of 0.05 nm. Experimental results have revealed that the central wavelength of the radiation adjustment at a pitch of 0.005 nm gives the possibility for the capacity of the array consisting of four opticalfiber sensors based on the fiber Bragg gratings. They are formed in one optical fiber under the Bragg grating temperature change from 0° C to 300° C and by the optical fiber mechanical stretching by the force up to 2 N.

Manipulations of Wavefront Propagation: Useful Methods and Applications for Interferometric Measurements and Scanning

Directory of Open Access Journals (Sweden)

Avi Karsenty

2017-01-01

Full Text Available Phase measurements obtained by high-coherence interferometry are restricted by the 2π ambiguity, to height differences smaller than λ/2. A further restriction in most interferometric systems is for focusing the system on the measured object. We present two methods that overcome these restrictions. In the first method, different segments of a measured wavefront are digitally propagated and focused locally after measurement. The divergent distances, by which the diverse segments of the wavefront are propagated in order to achieve a focused image, provide enough information so as to resolve the 2π ambiguity. The second method employs an interferogram obtained by a spectrum constituting a small number of wavelengths. The magnitude of the interferogram’s modulations is utilized to resolve the 2π ambiguity. Such methods of wavefront propagation enable several applications such as focusing and resolving the 2π ambiguity, as described in the article.

Noise analysis of the measurement of group delay in Fourier white-light interferometric cross correlation

International Nuclear Information System (INIS)

Laude, Vincent

2002-01-01

The problem of noise analysis in measuring the group delay introduced by a dispersive optical element by use of white-light interferometric cross correlation is investigated. Two noise types, detection noise and position noise, are specifically analyzed. Detection noise is shown to be highly sensitive to the spectral content of the white-light source at the frequency considered and to the temporal acquisition window. Position noise, which arises from the finite accuracy of the measurement of the scanning mirror's position, can severely damage the estimation of the group delay. Such is shown to be the case for fast Fourier transform-based estimation algorithms. A new algorithm that is insensitive to scanning delay errors is proposed, and subfemtosecond accuracy is obtained without any postprocessing

Imaging and chemical surface analysis of biomolecular functionalization of monolithically integrated on silicon Mach-Zehnder interferometric immunosensors

International Nuclear Information System (INIS)

Gajos, Katarzyna; Angelopoulou, Michailia; Petrou, Panagiota; Awsiuk, Kamil; Kakabakos, Sotirios; Haasnoot, Willem; Bernasik, Andrzej; Rysz, Jakub; Marzec, Mateusz M.; Misiakos, Konstantinos; Raptis, Ioannis; Budkowski, Andrzej

2016-01-01

Highlights: • Optimization of probe immobilization with robotic spotter printing overlapping spots. • In-situ inspection of microstructured surfaces of biosensors integrated on silicon. • Imaging and chemical analysis of immobilization, surface blocking and immunoreaction. • Insight with molecular discrimination into step-by-step sensor surface modifications. • Optimized biofunctionalization improves sensor sensitivity and response repeatability. - Abstract: Time-of-flight secondary ion mass spectrometry (imaging, micro-analysis) has been employed to evaluate biofunctionalization of the sensing arm areas of Mach-Zehnder interferometers monolithically integrated on silicon chips for the immunochemical (competitive) detection of bovine κ-casein in goat milk. Biosensor surfaces are examined after: modification with (3-aminopropyl)triethoxysilane, application of multiple overlapping spots of κ-casein solutions, blocking with 100-times diluted goat milk, and reaction with monoclonal mouse anti-κ-casein antibodies in blocking solution. The areas spotted with κ-casein solutions of different concentrations are examined and optimum concentration providing homogeneous coverage is determined. Coverage of biosensor surfaces with biomolecules after each of the sequential steps employed in immunodetection is also evaluated with TOF-SIMS, supplemented by Atomic force microscopy and X-ray photoelectron spectroscopy. Uniform molecular distributions are observed on the sensing arm areas after spotting with optimum κ-casein concentration, blocking and immunoreaction. The corresponding biomolecular compositions are determined with a Principal Component Analysis that distinguished between protein amino acids and milk glycerides, as well as between amino acids characteristic for Mabs and κ-casein, respectively. Use of the optimum conditions (κ-casein concentration) for functionalization of chips with arrays of ten Mach-Zehnder interferometers provided on-chips assays

Imaging and chemical surface analysis of biomolecular functionalization of monolithically integrated on silicon Mach-Zehnder interferometric immunosensors

Energy Technology Data Exchange (ETDEWEB)

Gajos, Katarzyna, E-mail: kasia.fornal@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Angelopoulou, Michailia; Petrou, Panagiota [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St, Aghia Paraksevi 15310, Athens (Greece); Awsiuk, Kamil [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Kakabakos, Sotirios [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St, Aghia Paraksevi 15310, Athens (Greece); Haasnoot, Willem [RIKILT Wageningen UR, Akkermaalsbos 2, 6708 WB Wageningen (Netherlands); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Rysz, Jakub [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Marzec, Mateusz M. [Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Misiakos, Konstantinos; Raptis, Ioannis [Department of Microelectronics, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, P. Grigoriou & Neapoleos St, Aghia Paraksevi 15310, Athens (Greece); Budkowski, Andrzej [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland)

2016-11-01

Highlights: • Optimization of probe immobilization with robotic spotter printing overlapping spots. • In-situ inspection of microstructured surfaces of biosensors integrated on silicon. • Imaging and chemical analysis of immobilization, surface blocking and immunoreaction. • Insight with molecular discrimination into step-by-step sensor surface modifications. • Optimized biofunctionalization improves sensor sensitivity and response repeatability. - Abstract: Time-of-flight secondary ion mass spectrometry (imaging, micro-analysis) has been employed to evaluate biofunctionalization of the sensing arm areas of Mach-Zehnder interferometers monolithically integrated on silicon chips for the immunochemical (competitive) detection of bovine κ-casein in goat milk. Biosensor surfaces are examined after: modification with (3-aminopropyl)triethoxysilane, application of multiple overlapping spots of κ-casein solutions, blocking with 100-times diluted goat milk, and reaction with monoclonal mouse anti-κ-casein antibodies in blocking solution. The areas spotted with κ-casein solutions of different concentrations are examined and optimum concentration providing homogeneous coverage is determined. Coverage of biosensor surfaces with biomolecules after each of the sequential steps employed in immunodetection is also evaluated with TOF-SIMS, supplemented by Atomic force microscopy and X-ray photoelectron spectroscopy. Uniform molecular distributions are observed on the sensing arm areas after spotting with optimum κ-casein concentration, blocking and immunoreaction. The corresponding biomolecular compositions are determined with a Principal Component Analysis that distinguished between protein amino acids and milk glycerides, as well as between amino acids characteristic for Mabs and κ-casein, respectively. Use of the optimum conditions (κ-casein concentration) for functionalization of chips with arrays of ten Mach-Zehnder interferometers provided on-chips assays

Ground and surface water for drinking: a laboratory study on genotoxicity using plant tests

Directory of Open Access Journals (Sweden)

Donatella Feretti

2012-02-01

Full Text Available Surface waters are increasingly utilized for drinking water because groundwater sources are often polluted. Several monitoring studies have detected the presence of mutagenicity in drinking water, especially from surface sources due to the reaction of natural organic matter with disinfectant. The study aimed to investigate the genotoxic potential of the products of reaction between humic substances, which are naturally present in surface water, and three disinfectants: chlorine dioxide, sodium hypochlorite and peracetic acid. Commercial humic acids dissolved in distilled water at different total organic carbon (TOC concentrations were studied in order to simulate natural conditions of both ground water (TOC=2.5 mg/L and surface water (TOC=7.5 mg/L. These solutions were treated with the biocides at a 1:1 molar ratio of C:disinfectant and tested for genotoxicity using the anaphase chromosomal aberration and micronucleus tests in Allium cepa, and the Vicia faba and Tradescantia micronucleus tests. The tests were carried out after different times and with different modes of exposure, and at 1:1 and 1:10 dilutions of disinfected and undisinfected humic acid solutions. A genotoxic effect was found for sodium hypochlorite in all plant tests, at both TOCs considered, while chlorine dioxide gave positive results only with the A.cepa tests. Some positive effects were also detected for PAA (A.cepa and Tradescantia. No relevant differences were found in samples with different TOC values. The significant increase in all genotoxicity end-points induced by all tested disinfectants indicates that a genotoxic potential is exerted even in the presence of organic substances at similar concentrations to those frequently present in drinking water.

A new dry-surface biofilm model: An essential tool for efficacy testing of hospital surface decontamination procedures.

Science.gov (United States)

Almatroudi, Ahmad; Hu, Honghua; Deva, Anand; Gosbell, Iain B; Jacombs, Anita; Jensen, Slade O; Whiteley, Greg; Glasbey, Trevor; Vickery, Karen

2015-10-01

The environment has been shown to be a source of pathogens causing infections in hospitalised patients. Incorporation of pathogens into biofilms, contaminating dry hospital surfaces, prolongs their survival and renders them tolerant to normal hospital cleaning and disinfection procedures. Currently there is no standard method for testing efficacy of detergents and disinfectants against biofilm formed on dry surfaces. The aim of this study was to develop a reproducible method of producing Staphylococcus aureus biofilm with properties similar to those of biofilm obtained from dry hospital clinical surfaces, for use in efficacy testing of decontamination products. The properties (composition, architecture) of model biofilm and biofilm obtained from clinical dry surfaces within an intensive care unit were compared. The CDC Biofilm Reactor was adapted to create a dry surface biofilm model. S. aureus ATCC 25923 was grown on polycarbonate coupons. Alternating cycles of dehydration and hydration in tryptone soy broth (TSB) were performed over 12 days. Number of biofilm bacteria attached to individual coupons was determined by plate culture and the coefficient of variation (CV%) calculated. The DNA, glycoconjugates and protein content of the biofilm were determined by analysing biofilm stained with SYTO 60, Alexa-488-labelled Aleuria aurantia lectin and SyproOrange respectively using Image J and Imaris software. Biofilm architecture was analysed using live/dead staining and confocal microscopy (CM) and scanning electron microscopy (SEM). Model biofilm was compared to naturally formed biofilm containing S. aureus on dry clinical surfaces. The CDC Biofilm reactor reproducibly formed a multi-layered, biofilm containing about 10(7) CFU/coupon embedded in thick extracellular polymeric substances. Within run CV was 9.5% and the between run CV was 10.1%. Protein was the principal component of both the in vitro model biofilm and the biofilms found on clinical surfaces. Continued

Spatially extended and high-velocity dispersion molecular component in spiral galaxies: Single-dish versus interferometric observations

International Nuclear Information System (INIS)

Caldú-Primo, Anahi; Walter, Fabian; Schruba, Andreas; Leroy, Adam; Bolatto, Alberto D.; Vogel, Stuart

2015-01-01

Recent studies of the molecular medium in nearby galaxies have provided mounting evidence that the molecular gas can exist in two phases: one that is clumpy and organized as molecular clouds and another one that is more diffuse. This last component has a higher velocity dispersion than the clumpy one. In order to investigate these two molecular components further, we compare the fluxes and line widths of CO in NGC 4736 and NGC 5055, two nearby spiral galaxies for which high-quality interferometric as well as single-dish data sets are available. Our analysis leads to two main results: (1) employing three different methods, we determine the flux recovery of the interferometer as compared to the single-dish to be within a range of 35%–74% for NGC 4736 and 81%–92% for NGC 5055, and (2) when focusing on high (S/N ≥ 5) lines of sight (LOSs), the single-dish line widths are larger by ∼(40 ± 20)% than the ones derived from interferometric data, which is in agreement with stacking all LOSs. These results point to a molecular gas component that is distributed over spatial scales larger than 30″(∼1 kpc), and is therefore filtered out by the interferometer. The available observations do not allow us to distinguish between a truly diffuse gas morphology and a uniform distribution of small clouds that are separated by less than the synthesized beam size (∼3″ or ∼100 pc), as they would both be invisible for the interferometer. This high velocity dispersion component has a dispersion similar to what is found in the atomic medium, as traced through observations of the H i line.

New formulas for interferometric crosstalk penalty as a function of total crosstalk power, number of crosstalk contributions and signal extinction ratio

OpenAIRE

Rasmussen, Christian Jørgen; Jeppesen, Palle

2000-01-01

Interferometric crosstalk, also called incoherent crosstalk, occurs when reception of a desired signal is disturbed by undesired crosstalk contributions having the same wavelength as the desired signal but independent amplitudes and phases. This crosstalk type is known to be among the most destructive phenomena in optical networks owing to its accumulative nature and strong impact on the transmission quality. New formulas state the crosstalk penalty as a function of the total crosstalk power,...

Dose Prediction for surface nuclear explosions: case studies for Semipalatinsk and Lop Nur tests

International Nuclear Information System (INIS)

Takada, Jun

2008-01-01

Dose prediction method RAPS after surface nuclear explosion has been developed by using the empirical dose function of USA nuclear test. This method which provides us external total dose, dose rate at any distant, at any time for any yield of nuclear explosion, is useful for radiation protection in case of nuclear events such as terrorism and nuclear war. The validity of RAPS has been confirmed by application to historical surface nuclear test explosions. The first test case study which was done for the first test explosion of the former USSR at the Semipalatinsk Nuclear Test Site on August 29th 1949, shows a good agreement with luminescence dosimetry on a brick. This dose prediction method was applied nuclear tests in Lop Nur. The results indicate dangerous nuclear radiation influences including fatal risk in the wide Uygur area. (author)

Improved Nanomechanical Test Techniques for Surface Engineered Materials

Directory of Open Access Journals (Sweden)

Stephen R. Goodes

2010-06-01

Full Text Available The development and implementation of a wide range of innovative nanomechanical test techniques to solve tribological problems in applications as diverse as biomedical and automotive are described in this review. For improved wear resistance and durability, the importance of understanding the system response rather than the coating-only properties is emphasized. There are many applications involving mechanical contact where the key to understanding the problem is to test at higher load and to combine reliable measurements taken across different length scales using both nano- and micro-indentation and related wear measurement techniques which more closely simulate contact conditions to fully understand the mechanical behaviour and hence deliver improved application performance. Results are presented with the NanoTest platform for applications for biomedical devices and surface engineering of lightweight alloys for the automotive industry. By combining results with different techniques it is possible to postulate predictive design rules – based on the elastic and plastic deformation energies involved in contact - to aid the reliable optimisation of mechanical properties in the various contact situations in the different applications.

Peeling tests for assessing the cohesion and consolidation characteristics of mortar and render surfaces

Czech Academy of Sciences Publication Activity Database

Drdácký, Miloš; Lesák, Jaroslav; Niedoba, Krzysztof; Valach, Jaroslav

2015-01-01

Roč. 48, č. 6 (2015), s. 1947-1963 ISSN 1359-5997 R&D Projects: GA ČR(CZ) GBP105/12/G059; GA MŠk(CZ) ED1.1.00/02.0060 Institutional support: RVO:68378297 Keywords : peeling test * rendered surface * surface consolidation * cohesion * non-destructive testing Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.453, year: 2015 http://link.springer.com/article/10.1617/s11527-014-0285-8

Determination of the transfer function for optical surface topography measuring instruments—a review

International Nuclear Information System (INIS)

Foreman, Matthew R; Török, Peter; Giusca, Claudiu L; Leach, Richard K; Coupland, Jeremy M

2013-01-01

A significant number of areal surface topography measuring instruments, largely based on optical techniques, are commercially available. However, implementation of optical instrumentation into production is currently difficult due to the lack of understanding of the complex interaction between the light and the component surface. Studying the optical transfer function of the instrument can help address this issue. Here a review is given of techniques for the measurement of optical transfer functions. Starting from the basis of a spatially coherent, monochromatic confocal scanning imaging system, the theory of optical transfer functions in three-dimensional (3D) imaging is presented. Further generalizations are reviewed allowing the extension of the theory to the description of conventional and interferometric 3D imaging systems. Polychromatic transfer functions and surface topography measurements are also discussed. Following presentation of theoretical results, experimental methods to measure the optical transfer function of each class of system are presented, with a focus on suitable methods for the establishment of calibration standards in 3D imaging and surface topography measurements. (topical review)

Nondestructive surface profiling of hidden MEMS using an infrared low-coherence interferometric microscope

Science.gov (United States)

Krauter, Johann; Osten, Wolfgang

2018-03-01

There are a wide range of applications for micro-electro-mechanical systems (MEMS). The automotive and consumer market is the strongest driver for the growing MEMS industry. A 100 % test of MEMS is particularly necessary since these are often used for safety-related purposes such as the ESP (Electronic Stability Program) system. The production of MEMS is a fully automated process that generates 90 % of the costs during the packaging and dicing steps. Nowadays, an electrical test is carried out on each individual MEMS component before these steps. However, after encapsulation, MEMS are opaque to visible light and other defects cannot be detected. Therefore, we apply an infrared low-coherence interferometer for the topography measurement of those hidden structures. A lock-in algorithm-based method is shown to calculate the object height and to reduce ghost steps due to the 2π -unambiguity. Finally, measurements of different MEMS-based sensors are presented.

Surface structural damage study in cortical bone due to medical drilling.

Science.gov (United States)

Tavera R, Cesar G; De la Torre-I, Manuel H; Flores-M, Jorge M; Hernandez M, Ma Del Socorro; Mendoza-Santoyo, Fernando; Briones-R, Manuel de J; Sanchez-P, Jorge

2017-05-01

A bone's fracture could be produced by an excessive, repetitive, or sudden load. A regular medical practice to heal it is to fix it in two possible ways: external immobilization, using a ferule, or an internal fixation, using a prosthetic device commonly attached to the bone by means of surgical screws. The bone's volume loss due to this drilling modifies its structure either in the presence or absence of a fracture. To observe the bone's surface behavior caused by the drilling effects, a digital holographic interferometer is used to analyze the displacement surface's variations in nonfractured post-mortem porcine femoral bones. Several nondrilled post-mortem bones are compressed and compared to a set of post-mortem bones with a different number of cortical drillings. During each compression test, a series of digital interferometric holograms were recorded using a high-speed CMOS camera. The results are presented as pseudo 3D mesh displacement maps for comparisons in the physiological range of load (30 and 50 lbs) and beyond (100, 200, and 400 lbs). The high resolution of the optical phase gives a better understanding about the bone's microstructural modifications. Finally, a relationship between compression load and bone volume loss due to the drilling was observed. The results prove that digital holographic interferometry is a viable technique to study the conditions that avoid the surgical screw from loosening in medical procedures of this kind.

Mid-Infrared Interferometric Monitoring of Evolved Stars: The Dust Shell Around the Mira Variable RR Aquilae at 13 Epochs

Science.gov (United States)

2011-01-01

photometric and interferometric data. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF...λ = 2.2 μm, Δλ = 0.4 μm) angular size with the Infrared Optical Telescope Array ( IOTA ). The uniform disk diameter (UD) of θUD = 10.73 ± 0.66 mas at...with IOTA in the H-band, and classified RR Aql as a target with no detectable asymmetries. The IRAS flux at 12 μm is 332 Jy. The light curve in the V

Direct Interferometric Imaging with IOTA Interferometer: Morphology of the Water Shell around U Ori

Science.gov (United States)

Pluzhnik, Eugene; Ragland, S.; Le Coroller, H.; Cotton, W.; Danchi, W.; Traub, W.; Willson, L.

2007-12-01

Optical interferometric observations of Mira stars with adequate resolution using the 3-telescope Infrared Optical Telescope Array (IOTA) interferometer have shown detectable asymmetry in several Mira stars. Several mechanisms have been proposed to explain the observed asymmetry. In this paper, we present subsequent IOTA observations of a Mira star, namely, U Ori taken at 1.51, 1.64 and 1.78 μm in 2005. The reconstructed images based on a model independent algorithm are also presented. These images show asymmetric structures of the water shell that is similar to the structure of 22 GHz masers obtained by Vlemmings et al. in 2003. We explore the possibility of the detection of molecular shell rotation with a period of about 30 years by comparing our results with radio observations and discuss a possible geometric structure of the shell.

Comparison in electron density distribution of tokamak plasma between ruby-laser scattering and milli-meter wave interferometric measurements

International Nuclear Information System (INIS)

Matoba, Tohru; Funahashi, Akimasa; Itagaki, Tokiyoshi; Takahashi, Koki; Kumagai, Katsuaki

1976-08-01

The electron density in JFT-2 tokamak has been measured by two methods, i.e. Thomson scattering of ruby-laser light and interferometry of millimeter wave. Two-dimensional distribution of the scattered light intensities were obtained by scattering measurement; absolute calibration was made by normalizing the scattered intensities with the averaged density determined from interferometric measurement. The horizontal density distributions in laser scattering were compared with those in from the averaged densities measured with a 4-mm interferometer through inverse-transformation. Agreement is good between the two measurements, except where they give erroneous data because of irreproducibility of the discharge. (auth.)

Quantitative impedance characterization of sub-10 nm scale capacitors and tunnel junctions with an interferometric scanning microwave microscope

International Nuclear Information System (INIS)

Wang, Fei; Clément, Nicolas; Ducatteau, Damien; Troadec, David; Legrand, Bernard; Dambrine, Gilles; Théron, Didier; Tanbakuchi, Hassan

2014-01-01

We present a method to characterize sub-10 nm capacitors and tunnel junctions by interferometric scanning microwave microscopy (iSMM) at 7.8 GHz. At such device scaling, the small water meniscus surrounding the iSMM tip should be reduced by proper tip tuning. Quantitative impedance characterization of attofarad range capacitors is achieved using an ‘on-chip’ calibration kit facing thousands of nanodevices. Nanoscale capacitors and tunnel barriers were detected through variations in the amplitude and phase of the reflected microwave signal, respectively. This study promises quantitative impedance characterization of a wide range of emerging functional nanoscale devices. (paper)

Detected Surface Effects of the September 3, 2017 Declared Nuclear Test

Science.gov (United States)

Pabian, F. V.

2017-12-01

Satellite-based synthetic aperture radar (SAR) data of North Korea's Punggye-ri Nuclear Test Site, together with new electro-optical commercial satellite imagery and a short official video (apparently recorded during the most recent test), provide additional insights on the widespread surface disturbances[1] around the peak of Mt. Mantap that were caused by North Korea's sixth and by far largest nuclear test (over one hundred kilotons). While a number of visible landslides have already been reported by this author and others, this additional data reveals more information about the widespread nature of the detected movements that indicate a general slumping/compression of the top 200 meters of the mountain consisting of loosely consolidated volcanic ash deposits above a nonconformity with underlying basement diorite/granites. A closer look at the one previously noted zone of localized slippage/subsidence located within the volcanic deposits, revealed that several healthy trees have been knocked down. The new image data empirically confirms previous seismological estimates that the detonation occurred somewhere under Mt. Mantap. The North Korean-sourced short video, which shows a large dust cloud rising up from the mountain along with a probable active rockfall in a pre-existing landslide scar, provides additional new evidence consistent with that conclusion. However, the broad-scale nature of those movements inhibits more precise geolocation of the test within the mountain using imagery. [1] Surface displacements include landslides, spall, cracks, rock falls, small fault displacements, and earth movement including slippage/subsidence within pre-existing surface features such as small depressions as previously reported here: http://www.38north.org/2017/01/fpabiandcoblentz010617/ and http://www.38north.org/2017/09/punggye090517/ and http://www.38north.org/2017/09/punggye091217/

The testing of sanitizers efficacy to enterococci adhered on glass surfaces

Directory of Open Access Journals (Sweden)

Margita Čanigová

2015-08-01

Full Text Available The aim of this work was to test the ability of 6 strains of enterococci to adhere on glass surfaces in environment with different content of milk residues and then to evaluate efficacy of 2 commercial sanitizers (alkaline and acidic used in milk production. Tested enterococci were isolated from milk, dairy products and from rinse water after sanitation milking machine. Suspension of enterococci (8 log CFU.ml-1 was prepared in phosphate buffered saline (PBS, PBS with content 0.1% and 1% of skimmed reconstituted milk. Glass plates were immersed into bacterial suspension for 1 h at 37 °C. The number of enterococci adhered on glass surface in PBS achieved an average value 3.47 log CFU.mm-2, in PBS with 0.1% of milk 2.90 CFU.mm-2, in PBS with 1% of milk 2.63 CFU.mm-2. Differences between the tested files were not statistically significant (p >0.05. In the second part of work the glass plates with adhered enterococci were exposed to the effect of alkaline sanitizer (on basis of NaOH and NaClO, respectively acidic sanitizer (on basis of H3PO4. Sanitation solutions were prepared and tested according to manufacturer recommendations (concentration 0.25%, contact time 20 min, temperature   20 °C. Alkaline sanitation solution was 100% effective against all tested enterococci regardless to content of milk residues in environment. Acidic sanitation solution was 100% effective only against E. faecalisD (isolated from rinse water after sanitation. Average value of reduction of enterococci with acidic sanitation solution, which were on glass plates in environment PBS was 2.84 CFU.mm-2, in PBS with 0.1% of milk was 2.45 CFU.mm-2 and in PBS with 1% of milk was 2.16 CFU.mm-2. It can be concluded, that increase of milk residues in environment decrease the adhesion of enterococci on glass surface, but also effectiveness of acidic sanitation solution.

Interferometrically enhanced sub-terahertz picosecond imaging utilizing a miniature collapsing-field-domain source

Science.gov (United States)

Vainshtein, Sergey N.; Duan, Guoyong; Mikhnev, Valeri A.; Zemlyakov, Valery E.; Egorkin, Vladimir I.; Kalyuzhnyy, Nikolay A.; Maleev, Nikolai A.; Näpänkangas, Juha; Sequeiros, Roberto Blanco; Kostamovaara, Juha T.

2018-05-01

Progress in terahertz spectroscopy and imaging is mostly associated with femtosecond laser-driven systems, while solid-state sources, mainly sub-millimetre integrated circuits, are still in an early development phase. As simple and cost-efficient an emitter as a Gunn oscillator could cause a breakthrough in the field, provided its frequency limitations could be overcome. Proposed here is an application of the recently discovered collapsing field domains effect that permits sub-THz oscillations in sub-micron semiconductor layers thanks to nanometer-scale powerfully ionizing domains arising due to negative differential mobility in extreme fields. This shifts the frequency limit by an order of magnitude relative to the conventional Gunn effect. Our first miniature picosecond pulsed sources cover the 100-200 GHz band and promise milliwatts up to ˜500 GHz. Thanks to the method of interferometrically enhanced time-domain imaging proposed here and the low single-shot jitter of ˜1 ps, our simple imaging system provides sufficient time-domain imaging contrast for fresh-tissue terahertz histology.

Coherent change detection and interferometric ISAR measurements in the folded compact range

Energy Technology Data Exchange (ETDEWEB)

Sorensen, K.W.

1996-08-01

A folded compact range configuration has been developed ant the Sandia National Laboratories` compact range antenna and radar-cross- section measurement facility as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) measurements of distributed target samples (i.e. gravel, sand, etc.). The folded compact range configuration has previously been used to perform coherent-change-detection (CCD) measurements, which allow disturbances to distributed targets on the order of fractions of a wavelength to be detected. This report describes follow-on CCD measurements of other distributed target samples, and also investigates the sensitivity of the CCD measurement process to changes in the relative spatial location of the SAR sensor between observations of the target. Additionally, this report describes the theoretical and practical aspects of performing interferometric inverse-synthetic-aperture-radar (IFISAR) measurements in the folded compact range environment. IFISAR measurements provide resolution of the relative heights of targets with accuracies on the order of a wavelength. Several examples are given of digital height maps that have been generated from measurements performed at the folded compact range facility.

Fatigue test results of flat plate specimens with surface cracks and evaluation of crack growth in structural components

International Nuclear Information System (INIS)

Shibata, Katsuyuki; Yokoyama, Norio; Ohba, Toshihiro; Kawamura, Takaichi; Miyazono, Shohachiro

1982-12-01

Part-through surface cracks are most frequently observed in the inspection of structural components, and it is one of the important subjects in the assessment of safety to evaluate appropriately the growth of such cracks during the service life of structural components. Due to the complexity of the stress at the front free surface, the crack growth at the surface shows a different behavior from the other part. Besides, an effect of interaction is caused in the growth of multiple surface cracks. These effects should be included in the growth analysis of surface part-through cracks. Authors have carried out a series of fatigue tests on some kinds of pipes with multiple cracks in the inner surface, and subsequently the fatigue test of flat plate specimens, made of Type 304L stainless steel, with a single or double surface cracks was carried out to study the basic characteristics in the growth of multiple surface cracks. Based on the results of the flat plate test. the correction factors for the front free surface (Cs) and interaction (Ci) of surface cracks were derived quantitatively by the following empirical expressions; Cs = 0.824. Ci = (0.227(a/b) 2 (sec(PI X/2) - 1) + 1)sup(1/m). Using these two correction factors, a procedure to predict the growth of surface cracks was developed by applying the crack growth formula to both the thickness and surface directions. Besides, the crack growth predictions based on the procedure of ASME Code Sex. XI, and the above procedure without the correction of the free surface and interactions on the crack growth behaviors were compared with the test results of flat plate specimens. The crack growth behavior predicted by the procedure described in this report showed the best agreement with the test results in respects of the crack growth life and the change in the crack shape. The criteria of the ASME Code did not agree with the test results. (author)

Decadal changes of surface elevation over permafrost area estimated using reflected GPS signals

Science.gov (United States)

Liu, Lin; Larson, Kristine M.

2018-02-01

Conventional benchmark-based survey and Global Positioning System (GPS) have been used to measure surface elevation changes over permafrost areas, usually once or a few times a year. Here we use reflected GPS signals to measure temporal changes of ground surface elevation due to dynamics of the active layer and near-surface permafrost. Applying the GPS interferometric reflectometry technique to the multipath signal-to-noise ratio data collected by a continuously operating GPS receiver mounted deep in permafrost in Barrow, Alaska, we can retrieve the vertical distance between the antenna and reflecting surface. Using this unique kind of observables, we obtain daily changes of surface elevation during July and August from 2004 to 2015. Our results show distinct temporal variations at three timescales: regular thaw settlement within each summer, strong interannual variability that is characterized by a sub-decadal subsidence trend followed by a brief uplift trend, and a secular subsidence trend of 0.26 ± 0.02 cm year-1 during 2004 and 2015. This method provides a new way to fully utilize data from continuously operating GPS sites in cold regions for studying dynamics of the frozen ground consistently and sustainably over a long time.

Fault detection by surface seismic scanning tunneling macroscope: Field test

KAUST Repository

Hanafy, Sherif M.

2014-08-05

The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

Fault detection by surface seismic scanning tunneling macroscope: Field test

KAUST Repository

Hanafy, Sherif M.; Schuster, Gerard T.

2014-01-01

The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

Laboratory and field testing results of the LMT/GTM primary surface actuators

Science.gov (United States)

Smith, David R.; Souccar, Kamal; Montalvo, Gabriela; Arteaga Magaña, César; Hernández Rebollar, José Luis; Olmos Tapia, Arak; Gallieni, Daniele; Lazzarini, Paolo; Fumi, Pierluigi; Anaclerio, Enzo

2016-07-01

With the final installation of the two outermost rings of the primary surface of the Large Millimeter Telescope/ Gran Telescopio Milimétrico (LMT/GTM), the project is also upgrading the primary surface actuators. There are commercial actuators that can approach the required operational accuracy and stroke, but the combination of the size and load requirements ultimately required a customized design. The new actuators fit within the volume constraints imposed by the tighter interior angles in the outer rings and are designed to support the operational and survival loading conditions even for the largest surface segments. Laboratory testing confirmed that the actuators should meet the precision, repeatability, load, and lifetime requirements. However, the LMT/GTM is at a particularly difficult site for electromechanical systems. The high altitude has the usual effect of reducing cooling effectiveness for the drives and motors, and the ambient temperature hovers near freezing. Since there is a significant amount of precipitation during some times of the year, there are frequent freeze/thaw cycles. The constant formation and either sublimation or melting of ice, along with the associated high humidity, has been a challenge for the environmental protection of many devices at the LMT/GTM. Because there are a total of 720 primary surface actuators in the system, it is particularly important that the actuators, their local drive control boxes, and their cable connections be able to meet its specifications even under the site conditions. To confirm the suitability of the actuators, the LMT/GTM procured an initial set of sixteen actuators for testing at the site. After laboratory testing, the actuators were installed into the outer two rings of the telescope and cycled during the early winter months of the 2015-16 scientific observing season. Because of the continuing installation activities in these two rings, they are not illuminated by the receivers, so field testing

Applied research for profilometric testing of the state of interior surfaces in heat exchanger tubes

International Nuclear Information System (INIS)

Gyongyosi, Tiberiu; Panaitescu, Valeriu Nicolae

2009-01-01

Generally, the surface flaws identified at heat exchangers tubing are characteristic for the heat secondary systems, located on the external surfaces of the heat exchanger tubes and are mostly the results of the ageing phenomena in systems operation. The tests performed, with the impressing replicating device confirmed the applicability of the technique, functionality of the device and resulted in replicas on metal support, these being the hard copy of the negative of the test tube surface, allowing the profile measurement. The visual inspection of the replicas on the metallic support gives information about the surface geometry replicated, pointing out the marks, which belong to the same area under observation. The minimum and maximum values for the depth of the channel worked out in the inner test tube wall have been determined by profile graphic measurement on the replicas. The paper presents the structural and functional description of the experimental devices. The first results and some conclusions are also included. Two patent applications were submitted at State Office for Inventions and Trademarks (OSIM) covering the original data to protect royalty: 'The local pit flaws, scratches, incipient micro-cracks replicating device on inner cylindrical surfaces', under no. A/00299/17.04.2008 and 'The annular local flaw, incipient micro-cracks replicating device on inner cylindrical surface' under no. A/00300/17.04.2008

In situ calibration of an interferometric velocity sensor for measuring small scale flow structures using a Talbot-pattern

Science.gov (United States)

König, Jörg; Czarske, Jürgen

2017-10-01

Small scale flow phenomena play an important role across engineering, biological and chemical sciences. To gain deeper understanding of the influence of those flow phenomena involved, measurement techniques with high spatial resolution are often required, presuming a calibration of very low uncertainty. To enable such measurements, a method for the in situ calibration of an interferometric flow velocity profile sensor is presented. This sensor, with demonstrated spatial resolution better than 1 μm, allows for spatially-resolving measurements with low velocity uncertainty in flows with high velocity gradients, on condition that the spatial behavior of the interference fringe systems is well-known by calibration with low uncertainty, especially challenging to obtain at applications with geometries difficult to access. The calibration method described herein uses three interfering beams to form the interference fringe systems of the sensor, yielding Doppler burst signals exhibiting two peaks in the frequency domain whose amplitude ratio varies periodically along the measurement volume major z-axis, giving a further independent value of the axial tracer particle position that can be used to determine the calibration functions of the sensor during the flow measurement. A flow measurement in a microchannel experimentally validates that the presented approach allows for simultaneously estimating the calibration functions and the velocity profile, providing flow measurements with very low systematic measurement errors of the particle position of less than 400 nm (confidence interval 95%). In that way, the interferometric flow velocity profile sensor utilizing the in situ self-calibration method promises valuable insights on small scale flow phenomena, such as those given in shear and boundary layer flows, by featuring reliable flow measurements due to minimum systematic and statistical measurement errors.

USB environment measurements based on full-scale static engine ground tests. [Upper Surface Blowing for YC-14

Science.gov (United States)

Sussman, M. B.; Harkonen, D. L.; Reed, J. B.

1976-01-01

Flow turning parameters, static pressures, surface temperatures, surface fluctuating pressures and acceleration levels were measured in the environment of a full-scale upper surface blowing (USB) propulsive-lift test configuration. The test components included a flightworthy CF6-50D engine, nacelle and USB flap assembly utilized in conjunction with ground verification testing of the USAF YC-14 Advanced Medium STOL Transport propulsion system. Results, based on a preliminary analysis of the data, generally show reasonable agreement with predicted levels based on model data. However, additional detailed analysis is required to confirm the preliminary evaluation, to help delineate certain discrepancies with model data and to establish a basis for future flight test comparisons.

Test data on electrical contacts at high surface velocities and high current densities for homopolar generators

International Nuclear Information System (INIS)

Brennan, M.; Tolk, K.M.; Weldon, W.F.; Rylander, H.G.; Woodson, H.H.

1977-01-01

Test data is presented for one grade of copper graphite brush material, Morganite CMlS, over a wide range of surface velocities, atmospheres, and current densities that are expected for fast discharge (<100 ms) homopolar generators. The brushes were run on a copper coated 7075-T6 aluminum disk at surface speeds up to 277 m/sec. One electroplated copper and three flame sprayed copper coatings were used during the tests. Significant differences in contact voltage drops and surface mechanical properties of the copper coatings were observed

Detection in coincidence of gravitational wave bursts with a network of interferometric detectors: Geometric acceptance and timing

International Nuclear Information System (INIS)

Arnaud, Nicolas; Barsuglia, Matteo; Bizouard, Marie-Anne; Canitrot, Philippe; Cavalier, Fabien; Davier, Michel; Hello, Patrice; Pradier, Thierry

2002-01-01

Detecting gravitational wave bursts (characterized by short durations and poorly modeled waveforms) requires coincidences between several interferometric detectors in order to reject nonstationary noise events. As the wave amplitude seen in a detector depends on its location with respect to the source direction and as the signal to noise ratio of these bursts is expected to be low, coincidences between antennas may not be very likely. This paper investigates this question from a statistical point of view by using a simple model of a network of detectors; it also estimates the timing precision of a detection in an interferometer, which is an important issue for the reconstruction of the source location based on time delays

New formulation for interferometric synthetic aperture radar for terrain mapping

Science.gov (United States)

Jakowatz, Charles V., Jr.; Wahl, Daniel E.; Eichel, Paul H.; Thompson, Paul A.

1994-06-01

The subject of interferometric synthetic aperture radar (IFSAR) for high-accuracy terrain elevation mapping continues to gain importance in the arena of radar signal processing. Applications to problems in precision terrain-aided guidance and automatic target recognition, as well as a variety of civil applications, are being studied by a number of researchers. Not unlike many other areas of SAR processing, the subject of IFSAR can, at first glance, appear to be somewhat mysterious. In this paper we show how the mathematics of IFSAR for terrain elevation mapping using a pair of spotlight mode SAR collections can be derived in a very straightforward manner. Here, we employ an approach that relies entirely on Fourier transforms, and utilizes no reference to range equations or Doppler concepts. The result is a simplified explanation of the fundamentals of interferometry, including an easily-seen link between image domain phase difference and terrain elevation height. The derivation builds upon previous work by the authors in which a framework for spotlight mode SAR image formation based on an analogy to 3D computerized axial tomography (CAT) was developed. After outlining the major steps in the mathematics, we show how a computer simulator which utilizes 3D Fourier transforms can be constructed that demonstrates all of the major aspects of IFSAR from spotlight mode collections.

Evidence for on-going inflation of the Socorro Magma Body, New Mexico, from interferometric synthetic aperture radar imaging

Science.gov (United States)

Fialko, Yuri; Simons, Mark

Interferometric synthetic aperture radar (InSAR) imaging of the central Rio Grande rift (New Mexico, USA) during 1992-1999 reveals a crustal uplift of several centimeters that spatially coincides with the seismologically determined outline of the Socorro magma body, one of the largest currently active magma intrusions in the Earth’s continental crust. Modeling of interferograms shows that the observed deformation may be due to elastic opening of a sill-like intrusion at a rate of a few millimeters per year. Despite an apparent constancy of the geodetically determined uplift rate, thermodynamic arguments suggest that it is unlikely that the Socorro magma body has formed via steady state elastic inflation.

Source effects on surface waves from Nevada Test Site explosions

International Nuclear Information System (INIS)

Patton, H.J.; Vergino, E.S.

1981-11-01

Surface waves recorded on the Lawrence Livermore National Laboratory (LLNL) digital network have been used to study five underground nuclear explosions detonated in Yucca Valley at the Nevada Test Site. The purpose of this study is to characterize the reduced displacement potential (RDP) at low frequencies and to test secondary source models of underground explosions. The observations consist of Rayleigh- and Love-wave amplitude and phase spectra in the frequency range 0.03 to 0.16 Hz. We have found that Rayleigh-wave spectral amplitudes are modeled well by a RDP with little or no overshoot for explosions detonated in alluvium and tuff. On the basis of comparisons between observed and predicted source phase, the spall closure source proposed by Viecelli does not appear to be a significant source of Rayleigh waves that reach the far field. We tested two other secondary source models, the strike-slip, tectonic strain release model proposed by Toksoez and Kehrer and the dip-slip thrust model of Masse. The surface-wave observations do not provide sufficient information to discriminate between these models at the low F-values (0.2 to 0.8) obtained for these explosions. In the case of the strike-slip model, the principal stress axes inferred from the fault slip angle and strike angle are in good agreement with the regional tectonic stress field for all but one explosion, Nessel. The results of the Nessel explosion suggest a mechanism other than tectonic strain release

InSAR detects increase in surface subsidence caused by an Arctic tundra fire

Science.gov (United States)

Liu, Lin; Jafarov, Elchin E.; Schaefer, Kevin M.; Jones, Benjamin M.; Zebker, Howard A.; Williams, Christopher A.; Rogan, John; Zhang, Tingjun

2014-01-01

Wildfire is a major disturbance in the Arctic tundra and boreal forests, having a significant impact on soil hydrology, carbon cycling, and permafrost dynamics. This study explores the use of the microwave Interferometric Synthetic Aperture Radar (InSAR) technique to map and quantify ground surface subsidence caused by the Anaktuvuk River fire on the North Slope of Alaska. We detected an increase of up to 8 cm of thaw-season ground subsidence after the fire, which is due to a combination of thickened active layer and permafrost thaw subsidence. Our results illustrate the effectiveness and potential of using InSAR to quantify fire impacts on the Arctic tundra, especially in regions underlain by ice-rich permafrost. Our study also suggests that surface subsidence is a more comprehensive indicator of fire impacts on ice-rich permafrost terrain than changes in active layer thickness alone.

Modelling the performance of interferometric gravitational-wave detectors with realistically imperfect optics

Science.gov (United States)

Bochner, Brett

1998-12-01

The LIGO project is part of a world-wide effort to detect the influx of Gravitational Waves upon the earth from astrophysical sources, via their interaction with laser beams in interferometric detectors that are designed for extraordinarily high sensitivity. Central to the successful performance of LIGO detectors is the quality of their optical components, and the efficient optimization of interferometer configuration parameters. To predict LIGO performance with optics possessing realistic imperfections, we have developed a numerical simulation program to compute the steady-state electric fields of a complete, coupled-cavity LIGO interferometer. The program can model a wide variety of deformations, including laser beam mismatch and/or misalignment, finite mirror size, mirror tilts, curvature distortions, mirror surface roughness, and substrate inhomogeneities. Important interferometer parameters are automatically optimized during program execution to achieve the best possible sensitivity for each new set of perturbed mirrors. This thesis includes investigations of two interferometer designs: the initial LIGO system, and an advanced LIGO configuration called Dual Recycling. For Initial-LIGO simulations, the program models carrier and sideband frequency beams to compute the explicit shot-noise-limited gravitational wave sensitivity of the interferometer. It is demonstrated that optics of exceptional quality (root-mean-square deformations of less than ~1 nm in the central mirror regions) are necessary to meet Initial-LIGO performance requirements, but that they can be feasibly met. It is also shown that improvements in mirror quality can substantially increase LIGO's sensitivity to selected astrophysical sources. For Dual Recycling, the program models gravitational- wave-induced sidebands over a range of frequencies to demonstrate that the tuned and narrow-banded signal responses predicted for this configuration can be achieved with imperfect optics. Dual Recycling

Relationship Between Ocular Surface Disease Index, Dry Eye Tests, and Demographic Properties in Computer Users

Directory of Open Access Journals (Sweden)

Hüseyin Simavlı

2014-03-01

Full Text Available Objectives: The aim of the present study is to evaluate the ocular surface disease index (OSDI in computer users and to investigate the correlations of this index with dry eye tests and demographic properties. Materials and Methods: In this prospective study, 178 subjects with an age range of 20-40 years and who spent most of their daily life in front of the computers were included. All participants underwent a complete ophthalmologic examination including basal secretion test, tear break-up time test, and ocular surface staining. In addition, all patients completed the OSDI questionnaire. Results: A total of 178 volunteers (101 female, 77 male with a mean age of 28.8±4.5 years were included in the study. Mean time of computer use was 7.7±1.9 (5-14 hours/day, and mean computer use period was 71.1±39.7 (4-204 months. Mean OSDI score was 44.1±24.7 (0-100. There was a significant negative correlation between the OSDI score and tear break-up time test in the right (p=0.005 r=-0.21 and the left eyes (p=0.003 r=-0.22. There was a significant positive correlation between the OSDI score and gender (p=0.014 r=0.18 and daily computer usage time (p=0.008 r=0.2. In addition to this, there was a significant positive correlation between the OSDI score and ocular surface staining pattern in the right (p=0.03 r=0.16 and the left eyes (p=0.03 r=0.17. Age, smoking, type of computer, use of glasses, presence of symptoms, and basal secretion test were not found to be correlated with OSDI score. Conclusions: Long-term computer use causes ocular surface problems. The OSDI were found to be correlated with tear break-up time test, gender, daily computer usage time, and ocular surface staining pattern in computer users. (Turk J Ophthalmol 2014; 44: 115-8

Comparison of filters for detecting gravitational wave bursts in interferometric detectors

International Nuclear Information System (INIS)

Arnaud, Nicolas; Barsuglia, Matteo; Bizouard, Marie-Anne; Brisson, Violette; Cavalier, Fabien; Davier, Michel; Hello, Patrice; Kreckelbergh, Stephane; Porter, Edward K.; Pradier, Thierry

2003-01-01

Filters developed in order to detect short bursts of gravitational waves in interferometric detector outputs are compared according to three main points. Conventional receiver operating characteristics (ROC) are first built for all the considered filters and for three typical burst signals. Optimized ROC are shown for a simple pulse signal in order to estimate the best detection efficiency of the filters in the ideal case, while realistic ones obtained with filters working with several 'templates' show how detection efficiencies can be degraded in a practical implementation. Second, estimations of biases and statistical errors on the reconstruction of the time of arrival of pulse-like signals are then given for each filter. Such results are crucial for future coincidence studies between gravitational wave detectors but also with neutrino or optical detectors. As most of the filters require a pre-whitening of the detector noise, the sensitivity to a nonperfect noise whitening procedure is finally analyzed. For this purpose lines of various frequencies and amplitudes are added to a Gaussian white noise and the outputs of the filters are studied in order to monitor the excess of false alarms induced by the lines. The comparison of the performances of the different filters finally show that they are complementary rather than competitive

Quantitative diffusion and swelling kinetic measurements using large-angle interferometric refractometry.

Science.gov (United States)

Saunders, John E; Chen, Hao; Brauer, Chris; Clayton, McGregor; Chen, Weijian; Barnes, Jack A; Loock, Hans-Peter

2015-12-07

The uptake and release of sorbates into films and coatings is typically accompanied by changes of the films' refractive index and thickness. We provide a comprehensive model to calculate the concentration of the sorbate from the average refractive index and the film thickness, and validate the model experimentally. The mass fraction of the analyte partitioned into a film is described quantitatively by the Lorentz-Lorenz equation and the Clausius-Mosotti equation. To validate the model, the uptake kinetics of water and other solvents into SU-8 films (d = 40-45 μm) were explored. Large-angle interferometric refractometry measurements can be used to characterize films that are between 15 μm to 150 μm thick and, Fourier analysis, is used to determine independently the thickness, the average refractive index and the refractive index at the film-substrate interface at one-second time intervals. From these values the mass fraction of water in SU-8 was calculated. The kinetics were best described by two independent uptake processes having different rates. Each process followed one-dimensional Fickian diffusion kinetics with diffusion coefficients for water into SU-8 photoresist film of 5.67 × 10(-9) cm(2) s(-1) and 61.2 × 10(-9) cm(2) s(-1).

Surface deformation analysis over Vrancea seismogenic area through radar and GPS geospatial data

Science.gov (United States)

Zoran, Maria A.; Savastru, Roxana S.; Savastru, Dan M.; Serban, Florin S.; Teleaga, Delia M.; Mateciuc, Doru N.

2017-10-01

Time series analysis of GPS (Global Positioning Systems) and InSAR (Interferometric Synthetic Aperture Radar) data are important tools for Earth's surface deformation assessment, which can result from a wide range of geological phenomena like as earthquakes, landslides or ground water level changes. The aim of this paper was to identify several types of earthquake precursors that might be observed from geospatial data in Vrancea seismogenic region in Romania. Continuous GPS Romanian network stations and few field campaigns data recorded between 2005-2012 years revealed a displacement of about 5 or 6 millimeters per year in horizontal direction relative motion, and a few millimeters per year in vertical direction. In order to assess possible deformations due to earthquakes and respectively for possible slow deformations, have been used also time series Sentinel 1 satellite data available for Vrancea zone during October 2014 till October 2016 to generate two types of interferograms (short-term and medium- term). During investigated period were not recorded medium or strong earthquakes, so interferograms over test area revealed small displacements on vertical direction (subsidence or uplifts) of 5-10 millimeters per year. Based on GPS continuous network data and satellite Sentinel 1 results, different possible tectonic scenarios were developed. The localization of horizontal and vertical motions, fault slip, and surface deformation of the continental blocks provides new information, in support of different geodynamic models for Vrancea tectonic active region in Romania and Europe.

Surface and near surface defect detection in thick copper EB-welds using eddy current testing

International Nuclear Information System (INIS)

Pitkaenen, J.; Lipponen, A.

2010-01-01

The surface inspection of thick copper electron beam (EB) welds plays an important role in the acceptance of nuclear fuel disposal. The main reasons to inspect these components are related to potential manufacturing and handling defects. In this work the data acquisition software, visualising tools for eddy current (EC) measurements and eddy current sensors were developed for detection of unwanted defects. The eddy current equipment was manufactured by IZFP and the visualising software in active co-operation with Posiva and IZFP for the inspections. The inspection procedure was produced during the development of the inspection techniques. The inspection method development aims to qualify the method for surface and near surface defect detection and sizing according to ENIQ. The study includes technical justification to be carried out, and compilation of a defect catalogue and experience from measurements within the Posiva's research on issues related to manufacturing. The depth of penetration in copper components in eddy current testing is rather small. To detect surface breaking defects the eddy current inspection is a good solution. A simple approach was adopted using two techniques: higher frequency was used to detect surface defects and to determine the dimensions of the defects except depth, lower frequency was used to detect defects having a ligament and for sizing of deeper surface breaking defects. The higher frequency was 30 kHz and the lower frequency was 200 Hz. The higher frequency probes were absolute bobbing coils and lower frequency probes combined transmitter - several receiver coils. To evaluate both methods, calibration blocks were manufactured by FNS for weld inspections. These calibration specimens mainly consisted of electron discharge machined notches and holes of varying shapes, lengths and diameters in the range of 1 mm to 20 mm of depth. Also one copper lid specimen with 152 defects was manufactured and used for evaluation of weld inspection

Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet

Science.gov (United States)

Albright, Thomas P.; Painter, Thomas H.; Roberts, Dar A.; Shi, Jiancheng; Dozier, Jeff; Fielding, Eric

1998-01-01

Imaging radar is a promising tool for mapping snow and ice cover in alpine regions. It combines a high-resolution, day or night, all-weather imaging capability with sensitivity to hydrologic and climatic snow and ice parameters. We use the spaceborne imaging radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) to map snow and glacial ice on the rugged north slope of Mount Everest. From interferometrically derived digital elevation data, we compute the terrain calibration factor and cosine of the local illumination angle. We then process and terrain-correct radar data sets acquired on April 16, 1994. In addition to the spectral data, we include surface slope to improve discrimination among several surface types. These data sets are then used in a decision tree to generate an image classification. This method is successful in identifying and mapping scree/talus, dry snow, dry snow-covered glacier, wet snow-covered glacier, and rock-covered glacier, as corroborated by comparison with existing surface cover maps and other ancillary information. Application of the classification scheme to data acquired on October 7 of the same year yields accurate results for most surface types but underreports the extent of dry snow cover.

Interferometric Reflectance Imaging Sensor (IRIS—A Platform Technology for Multiplexed Diagnostics and Digital Detection

Directory of Open Access Journals (Sweden)

Oguzhan Avci

2015-07-01

Full Text Available Over the last decade, the growing need in disease diagnostics has stimulated rapid development of new technologies with unprecedented capabilities. Recent emerging infectious diseases and epidemics have revealed the shortcomings of existing diagnostics tools, and the necessity for further improvements. Optical biosensors can lay the foundations for future generation diagnostics by providing means to detect biomarkers in a highly sensitive, specific, quantitative and multiplexed fashion. Here, we review an optical sensing technology, Interferometric Reflectance Imaging Sensor (IRIS, and the relevant features of this multifunctional platform for quantitative, label-free and dynamic detection. We discuss two distinct modalities for IRIS: (i low-magnification (ensemble biomolecular mass measurements and (ii high-magnification (digital detection of individual nanoparticles along with their applications, including label-free detection of multiplexed protein chips, measurement of single nucleotide polymorphism, quantification of transcription factor DNA binding, and high sensitivity digital sensing and characterization of nanoparticles and viruses.

Eastern Denali Fault surface trace map, eastern Alaska and Yukon, Canada

Science.gov (United States)

Bender, Adrian M.; Haeussler, Peter J.

2017-05-04

We map the 385-kilometer (km) long surface trace of the right-lateral, strike-slip Denali Fault between the Totschunda-Denali Fault intersection in Alaska, United States and the village of Haines Junction, Yukon, Canada. In Alaska, digital elevation models based on light detection and ranging and interferometric synthetic aperture radar data enabled our fault mapping at scales of 1:2,000 and 1:10,000, respectively. Lacking such resources in Yukon, we developed new structure-from-motion digital photogrammetry products from legacy aerial photos to map the fault surface trace at a scale of 1:10,000 east of the international border. The section of the fault that we map, referred to as the Eastern Denali Fault, did not rupture during the 2002 Denali Fault earthquake (moment magnitude 7.9). Seismologic, geodetic, and geomorphic evidence, along with a paleoseismic record of past ground-rupturing earthquakes, demonstrate Holocene and contemporary activity on the fault, however. This map of the Eastern Denali Fault surface trace complements other data sets by providing an openly accessible digital interpretation of the location, length, and continuity of the fault’s surface trace based on the accompanying digital topography dataset. Additionally, the digitized fault trace may provide geometric constraints useful for modeling earthquake scenarios and related seismic hazard.

AN INTERFEROMETRIC AND SPECTROSCOPIC ANALYSIS OF THE MULTIPLE STAR SYSTEM HD 193322

International Nuclear Information System (INIS)

Ten Brummelaar, Theo A.; Farrington, Christopher D.; Schaefer, Gail H.

2011-01-01

The star HD 193322 is a remarkable multiple system of massive stars that lies at the heart of the cluster Collinder 419. Here we report on new spectroscopic observations and radial velocities of the narrow-lined component Ab1 which we use to determine its orbital motion around a close companion Ab2 (P = 312 days) and around a distant third star Aa (P = 35 years). We have also obtained long baseline interferometry of the target in the K' band with the CHARA Array which we use in two ways. First, we combine published speckle interferometric measurements with CHARA separated fringe packet measurements to improve the visual orbit for the wide Aa,Ab binary. Second, we use measurements of the fringe packet from Aa to calibrate the visibility of the fringes of the Ab1,Ab2 binary, and we analyze these fringe visibilities to determine the visual orbit of the close system. The two most massive stars, Aa and Ab1, have masses of approximately 21 and 23 M sun , respectively, and their spectral line broadening indicates that they represent extremes of fast and slow projected rotational velocity, respectively.

Jet-Surface Interaction: High Aspect Ratio Nozzle Test, Nozzle Design and Preliminary Data

Science.gov (United States)

Brown, Clifford; Dippold, Vance

2015-01-01

The Jet-Surface Interaction High Aspect Ratio (JSI-HAR) nozzle test is part of an ongoing effort to measure and predict the noise created when an aircraft engine exhausts close to an airframe surface. The JSI-HAR test is focused on parameters derived from the Turbo-electric Distributed Propulsion (TeDP) concept aircraft which include a high-aspect ratio mailslot exhaust nozzle, internal septa, and an aft deck. The size and mass flow rate limits of the test rig also limited the test nozzle to a 16:1 aspect ratio, half the approximately 32:1 on the TeDP concept. Also, unlike the aircraft, the test nozzle must transition from a single round duct on the High Flow Jet Exit Rig, located in the AeroAcoustic Propulsion Laboratory at the NASA Glenn Research Center, to the rectangular shape at the nozzle exit. A parametric nozzle design method was developed to design three low noise round-to-rectangular transitions, with 8:1, 12:1, and 16: aspect ratios, that minimizes flow separations and shocks while providing a flat flow profile at the nozzle exit. These designs validated using the WIND-US CFD code. A preliminary analysis of the test data shows that the actual flow profile is close to that predicted and that the noise results appear consistent with data from previous, smaller scale, tests. The JSI-HAR test is ongoing through October 2015. The results shown in the presentation are intended to provide an overview of the test and a first look at the preliminary results.

Selection Criteria and Methods for Testing Different Surface Materials for Contact Frying Processes

DEFF Research Database (Denmark)

Ashokkumar, Saranya

Inner surfaces of industrial process equipment for food are often coated to give the surfaces particular properties with respect to adhesion and cleanability. Existing coating materials (PTFE (Teflon®) or silicone based polymers) suffer from drawbacks when used in contact frying, because these co...... surface materials for contact frying processes. The surfaces selected for this purpose cover a wide spectrum of materials that range from hydrophobic to hydrophilic materials. The different surface materials investigated include stainless steel (reference), aluminium (Al Mg 5754), PTFE......, an experimental rig has been constructed which enabled a controlled fouling of different coatings on steel and aluminium substrates under realistic frying conditions. A subjective rating procedure was employed for screening different surfaces according to their non-stick properties when used for frying of a model...... defects and surface roughness play a significant role. The wear resistance of the coatings was tested by performing abrasive wear experiments. The ceramic coatings: TiAlN and ZrN were found to show the best wear resistance properties. The experiments also revealed the poor wear resistance of stainless...

Do European Standard Disinfectant tests truly simulate in-use microbial and organic soiling conditions on food preparation surfaces?

Science.gov (United States)

Meyer, B; Morin, V N; Rödger, H-J; Holah, J; Bird, C

2010-04-01

The results from European standard disinfectant tests are used as one basis to approve the use of disinfectants in Europe. The design of these laboratory-based tests should thus simulate as closely as possible the practical conditions and challenges that the disinfectants would encounter in use. No evidence is available that the organic and microbial loading in these tests simulates actual levels in the food service sector. Total organic carbon (TOC) and total viable count (TVC) were determined on 17 visibly clean and 45 visibly dirty surfaces in two restaurants and the food preparation surfaces of a large retail store. These values were compared to reference values recovered from surfaces soiled with the organic and microbial loading, following the standard conditions of the European Surface Test for bactericidal efficacy, EN 13697. The TOC reference values for clean and dirty conditions were higher than the data from practice, but cannot be regarded as statistical outliers. This was considered as a conservative assessment; however, as additional nine TOC samples from visibly dirty surfaces were discarded from the analysis, as their loading made them impossible to process. Similarly, the recovery of test organisms from surfaces contaminated according to EN 13697 was higher than the TVC from visibly dirty surfaces in practice; though they could not be regarded as statistical outliers of the whole data field. No correlation was found between TVC and TOC in the sampled data, which re-emphasizes the potential presence of micro-organisms on visibly clean surfaces and thus the need for the same degree of disinfection as visibly dirty surfaces. The organic soil and the microbial burden used in EN disinfectant standards represent a realistic worst-case scenario for disinfectants used in the food service and food-processing areas.

Description and testing of three moisture sensors for measuring surface wetness on carbonate building stones

Science.gov (United States)

See, R.B.; Reddy, M.M.; Martin, R.G.

1988-01-01

Three moisture sensors were tested as a means for determining the surface wetness on carbonate building stones exposed to conditions that produce deposition of moisture. A relative-humidity probe, a gypsum-coated circuit grid, and a limestone-block resistor were tested as sensors for determining surface wetness. Sensors were tested under laboratory conditions of constant relative humidity and temperature and also under on-site conditions of variable relative humidity and temperature for eight weeks at Newcomb, NY. Laboratory tests indicated that relative humidity alone did not cause sensors to become saturated with water. However, the rates of drying indicated by the sensors after an initial saturation were inversely related to the relative humidity. On-site testing of the relative-humidity probe and the gypsum-coated ciruit grid indicated that they respond to a diurnal wetting and drying cycle; the limestone-block resistor responded only to rainfall.

Final Test at the Surface of the ATLAS Endcap Muon Trigger Chamber Electronics

CERN Document Server

Kubota, T; Kanaya, N; Kawamoto, T; Kobayashi, T; Kuwabara, T; Nomoto, H; Sakamoto, H; Yamaguchi, T; Fukunaga, C; Ikeno, M; Iwasaki, H; Nagano, K; Nozaki, M; Sasaki, O; Tanaka, S; Yasu, Y; Hasegawa, Y; Oshita, H; Takeshita, T; Nomachi, M; Sugaya, Y; Sugimoto, T; Okumura, Y; Takahashi, Y; Tomoto, M; Kadosaka, T; Kawagoe, K; Kiyamura, H; Kurashige, H; Niwa, T; Ochi, A; Omachi, C; Takeda, H; Lifshitz, R; Lupu, N; Bressler, S; Tarem, S; Kajomovitz, E; Ben Ami, S; Bahat Treidel, O; Benhammou, Ya; Etzion, E; Lellouch, D; Levinson, L; Mikenberg, G; Roich, A

2007-01-01

For the detector commissioning planned in 2007, sector assembly of the ATLAS muon-endcap trigger chambers and final test at the surface for the assembled electronics are being done in CERN and almost completed. For the test, we built up the Data Acquisition (DAQ) system using test pulse of two types and cosmic rays in order to check functionality of the various aspects of the electronics mounted on a sector. So far, 99% of all 320,000 channels have been tested and most of them were installed into the ATLAS cavern. In this presentation, we will describe the DAQ systems and mass-test procedure in detail, and report the result of electronics test with some actual experiences

Evaluation of penicylinders used in disinfectant testing: bacterial attachment and surface texture.

Science.gov (United States)

Cole, E C; Rutala, W A; Carson, J L

1987-01-01

Two possible deficiencies in the AOAC use-dilution method for registration of chemical disinfectants by the Environmental Protection Agency are examined: (1) the physical disparities among brands of penicylinders and (2) the variability of bacterial numbers on penicylinders depending upon test strain and penicylinder surface texture. Textural differences of 2 brands of stainless steel penicylinders, one brand of porcelain, and one brand of glass were assessed by scanning electron microscopy. A considerable variation in smoothness of both inner and outer surfaces of stainless steel and porcelain penicylinders was observed. Glass penicylinders were very smooth. Numbers of bacteria attached to a penicylinder were assessed by vortexing the penicylinders 30 s at No. 4 after using the AOAC method of bacterial inoculation and drying 40 min at 37 degrees C. With this methodology, stainless steel carriers retained the 3 AOAC-recommended bacterial test strains differentially: ca 10(7) for Pseudomonas aeruginosa, 5 X 10(6) for Staphylococcus aureus, and 10(6) for Salmonella choleraesuis; glass retained 10(6)-10(7) organisms of all 3 test strains; porcelain retained about that amount of S. aureus but 10(5)-10(6) P. aeruginosa and 10(3)-10(4) S. choleraesuis. These data suggest that disinfectants are not similarly challenged with the AOAC-recommended test bacteria and that an alternative method should be considered to ensure comparable numbers of bacteria on penicylinders.

Standard test method for determination of surface lubrication on flexible webs

CERN Document Server

American Society for Testing and Materials. Philadelphia

1999-01-01

1.1 This test method has been used since 1988 as an ANSI/ISO standard test for determination of lubrication on processed photographic films. Its purpose was to determine the presence of process-surviving lubricants on photographic films. It is the purpose of this test method to expand the applicability of this test method to other flexible webs that may need lubrication for suitable performance. This test measures the breakaway (static) coefficient of friction of a metal rider on the web by the inclined plane method. The objectives of the test is to determine if a web surface has a lubricant present or not. It is not intended to assign a friction coefficient to a material. It is not intended to rank lubricants. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

Production and testing of an s-band resonator with a Nb3Sn surface

International Nuclear Information System (INIS)

Peiniger, M.

1983-01-01

This report describes the preparation of a niobium s-band resonator with Nb3Sn surface using a special vapor phase deposition method. High-frequency superconductivity tests were performed on this resonator. Measurements of transition temperature, penetration depth, energy gap, and temperature dependence of surface conductivity of Nb3Sn, and resonator behaviour at high electrical field strengths are reported. (GSCH)

GIS surface effects archive of underground nuclear detonations conducted at Yucca Flat and Pahute Mesa, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

Grasso, D.N.

2001-01-01

This report presents a new comprehensive, digital archive of more than 40 years of geologic surface effects maps produced at individual detonation sites throughout the Yucca Flat and Pahute Mesa nuclear testing areas of the Nevada Test Site, Nye County, Nevada. The Geographic Information System (GIS) surface effects map archive on CD-ROM (this report) comprehensively documents the surface effects of underground nuclear detonations conducted at two of the most extensively used testing areas of the Nevada Test Site. Between 1951 and 1992, numerous investigators of the U.S. Geological Survey, the Los Alamos National Laboratory, the Lawrence Livermore National Laboratory, and the Defense Threat Reduction Agency meticulously mapped the surface effects caused by underground nuclear testing. Their work documented the effects of more than seventy percent of the underground nuclear detonations conducted at Yucca Flat and all of the underground nuclear detonations conducted at Pahute Mesa

Three-beam interferogram analysis method for surface flatness testing of glass plates and wedges

Science.gov (United States)

Sunderland, Zofia; Patorski, Krzysztof

2015-09-01

When testing transparent plates with high quality flat surfaces and a small angle between them the three-beam interference phenomenon is observed. Since the reference beam and the object beams reflected from both the front and back surface of a sample are detected, the recorded intensity distribution may be regarded as a sum of three fringe patterns. Images of that type cannot be succesfully analyzed with standard interferogram analysis methods. They contain, however, useful information on the tested plate surface flatness and its optical thickness variations. Several methods were elaborated to decode the plate parameters. Our technique represents a competitive solution which allows for retrieval of phase components of the three-beam interferogram. It requires recording two images: a three-beam interferogram and the two-beam one with the reference beam blocked. Mutually subtracting these images leads to the intensity distribution which, under some assumptions, provides access to the two component fringe sets which encode surfaces flatness. At various stages of processing we take advantage of nonlinear operations as well as single-frame interferogram analysis methods. Two-dimensional continuous wavelet transform (2D CWT) is used to separate a particular fringe family from the overall interferogram intensity distribution as well as to estimate the phase distribution from a pattern. We distinguish two processing paths depending on the relative density of fringe sets which is connected with geometry of a sample and optical setup. The proposed method is tested on simulated data.

Current practices in corrosion, surface characterization, and nickel leach testing of cardiovascular metallic implants.

Science.gov (United States)

Nagaraja, Srinidhi; Di Prima, Matthew; Saylor, David; Takai, Erica

2017-08-01

In an effort to better understand current test practices and improve nonclinical testing of cardiovascular metallic implants, the Food and Drug Administration (FDA) held a public workshop on Cardiovascular Metallic Implants: corrosion, surface characterization, and nickel leaching. The following topics were discussed: (1) methods used for corrosion assessments, surface characterization techniques, and nickel leach testing of metallic cardiovascular implant devices, (2) the limitations of each of these in vitro tests in predicting in vivo performance, (3) the need, utility, and circumstances when each test should be considered, and (4) the potential testing paradigms, including acceptance criteria for each test. In addition to the above topics, best practices for these various tests were discussed, and knowledge gaps were identified. Prior to the workshop, discussants had the option to provide feedback and information on issues relating to each of the topics via a voluntary preworkshop assignment. During the workshop, the pooled responses were presented and a panel of experts discussed the results. This article summarizes the proceedings of this workshop and background information provided by workshop participants. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. J Biomed Mater Res Part B: Appl Biomater, 105B: 1330-1341, 2017. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Surface flaw evaluation by vectorized eddy current testing image

International Nuclear Information System (INIS)

Endo, Hisashi; Takagi, Toshiyuki

2006-01-01

A method of eddy current testing (ECT) data mapping for surface breaking evaluation is studied. The multicoil ECT probe utilized in this paper consists of Transmit-Receive (TR) type sensors as array elements to obtain the information on crack directions. Switching two directional scans, U- and T- modes, gives two-dimensional vector mapping as ECT images. The ECT signals of the TR type sensor also give the information on crack directions from their variation displayed on the complex number plane. Extracting a complex number component of the signals makes it possible to visualize directions of numerically simulated proximate EDM slits. (author)

Advanced SAR Interferometric Analysis to Support Geomorphological Interpretation of Slow-Moving Coastal Landslides (Malta, Mediterranean Sea

Directory of Open Access Journals (Sweden)

Matteo Mantovani

2016-05-01

Full Text Available An advanced SAR interferometric analysis has been combined with a methodology for the automatic classification of radar reflectors phase histories to interpret slope-failure kinematics and trend of displacements of slow-moving landslides. To accomplish this goal, the large dataset of radar images, acquired in more than 20 years by the two European Space Agency (ESA missions ERS-1/2 and ENVISAT, was exploited. The analysis was performed over the northern sector of Island of Malta (central Mediterranean Sea, where extensive landslides occur. The study was assisted by field surveys and with the analysis of existing thematic maps and landslide inventories. The outcomes allowed definition of a model capable of describing the geomorphological evolution of slow-moving landslides, providing a key for interpreting such phenomena that, due to their slowness, are usually scarcely investigated.

Fiber optic sensor applications in field testing

International Nuclear Information System (INIS)

Perea, J.A.

1984-01-01

Fiber optic sensors (F.O.S.) are defined, and the application of this technology to measuring various phenomonon in diverse and hostile environments are discussed. F.O.S. advantages and disavantages both technically and operationally are summarized. Three sensor techniques - intensity, interferometric, and polarization - are then discussed in some detail. General environmental instrumentation and controls that support the Nuclear Weapons Test Program at the Nevada Test Site are discussed next to provide the reader with a basic understanding of the programmatic task. This will aid in recognizing the various difficulties of the traditional measurement techniques at the NTS and the potential advantages that fiber optic measurement systems can provide. An F.O.S. development program is then outlined, depicting a plan to design and fabricate a prototype sensor to be available for field testing by the end of FY84. We conclude with future plans for further development of F.O.S. to measure more of the desired physical parameters for the Test Program, and to eventually become an integral part of an overall measurement and control system

Relativistic generalization of the Van-Cittert-Zernike theorem and coherent properties of rotating star radiation

International Nuclear Information System (INIS)

Mandjos, A.V.; Khmil', S.V.

1979-01-01

The formula is derived for the complex coherence degree of radiation from the surface moving arbitrarily in the gravitational field. The calculations are carried out referina to the rotating star observed at the spectral line by the interferometric method. The possibility of determining interferometrically the star rotational velocity and axis orientation is grounded

Yield surface investigation of alloys during model disk spin tests

Directory of Open Access Journals (Sweden)

E. P. Kuzmin

2014-01-01

Full Text Available Gas-turbine engines operate under heavy subsequently static loading conditions. Disks of gas-turbine engine are high loaded parts of irregular shape having intensive stress concentrators wherein a 3D stress strain state occurs. The loss of load-carrying capability or burst of disk can lead to severe accident or disaster. Therefore, development of methods to assess deformations and to predict burst is one of the most important problems.Strength assessment approaches are used at all levels of engine creation. In recent years due to actively developing numerical method, particularly FEA, it became possible to investigate load-carrying capability of irregular shape disks, to use 3D computing schemes including flow theory and different options of force and deformation failure criteria. In spite of a wide progress and practical use of strength assessment approaches, there is a lack of detailed research data on yield surface of disk alloys. The main purpose of this work is to validate the use of basis hypothesis of flow theory and investigate the yield surface of disk alloys during the disks spin test.The results of quasi-static numerical simulation of spin tests of model disk made from high-temperature forged alloy are presented. To determine stress-strain state of disk during loading finite element analysis is used. Simulation of elastic-plastic strain fields was carried out using incremental theory of plasticity with isotropic hardening. Hardening function was taken from the results of specimens tensile test. Specimens were cut from a sinkhead of model disk. The paper investigates the model sensitivity affected by V.Mises and Tresca yield criteria as well as the Hosford model. To identify the material model parameters the eddy current sensors were used in the experimental approach to measure rim radial displacements during the load-unload of spin test. The results of calculation made using different material models were compared with the

Evaporation dynamics of completely wetting drops on geometrically textured surfaces

Science.gov (United States)

Mekhitarian, Loucine; Sobac, Benjamin; Dehaeck, Sam; Haut, Benoît; Colinet, Pierre

2017-10-01

This study deals with the evaporation dynamics of completely wetting and highly volatile drops deposited on geometrically textured but chemically homogeneous surfaces. The texturation consists in a cylindrical pillars array with a square pitch. The triple line dynamics and the drop shape are characterized by an interferometric method. A parametric study is realized by varying the radius and the height of the pillars (at fixed interpillar distance), allowing to distinguish three types of dynamics: i) an evaporation-dominated regime with a receding triple line; ii) a spreading-dominated regime with an initially advancing triple line; iii) a cross-over region with strong pinning effects. The overall picture is in qualitative agreement with a mathematical model showing that the selected regime mostly depends on the value of a dimensionless parameter comparing the time scales for evaporation and spreading into the substrate texture.

Hydraulic Characterization of Overpressured Tuffs in Central Yucca Flat, Nevada Test Site, Nye County, Nevada

Energy Technology Data Exchange (ETDEWEB)

K.J. Halford; R.J. Laczniak; D.L. Galloway

2005-10-07

A sequence of buried, bedded, air-fall tuffs has been used extensively as a host medium for underground nuclear tests detonated in the central part of Yucca Flat at the Nevada Test Site. Water levels within these bedded tuffs have been elevated hundreds of meters in areas where underground nuclear tests were detonated below the water table. Changes in the ground-water levels within these tuffs and changes in the rate and distribution of land-surface subsidence above these tuffs indicate that pore-fluid pressures have been slowly depressurizing since the cessation of nuclear testing in 1992. Declines in ground-water levels concurrent with regional land subsidence are explained by poroelastic deformation accompanying ground-water flow as fluids pressurized by underground nuclear detonations drain from the host tuffs into the overlying water table and underlying regional carbonate aquifer. A hydraulic conductivity of about 3 x 10-6 m/d and a specific storage of 9 x 10-6 m-1 are estimated using ground-water flow models. Cross-sectional and three-dimensional ground-water flow models were calibrated to measured water levels and to land-subsidence rates measured using Interferometric Synthetic Aperture Radar. Model results are consistent and indicate that about 2 million m3 of ground water flowed from the tuffs to the carbonate rock as a result of pressurization caused by underground nuclear testing. The annual rate of inflow into the carbonate rock averaged about 0.008 m/yr between 1962 and 2005, and declined from 0.005 m/yr in 2005 to 0.0005 m/yr by 2300.

An atomic gravitational wave interferometric sensor in low earth orbit (AGIS-LEO)

Science.gov (United States)

Hogan, Jason M.; Johnson, David M. S.; Dickerson, Susannah; Kovachy, Tim; Sugarbaker, Alex; Chiow, Sheng-Wey; Graham, Peter W.; Kasevich, Mark A.; Saif, Babak; Rajendran, Surjeet; Bouyer, Philippe; Seery, Bernard D.; Feinberg, Lee; Keski-Kuha, Ritva

2011-07-01

We propose an atom interferometer gravitational wave detector in low Earth orbit (AGIS-LEO). Gravitational waves can be observed by comparing a pair of atom interferometers separated by a 30 km baseline. In the proposed configuration, one or three of these interferometer pairs are simultaneously operated through the use of two or three satellites in formation flight. The three satellite configuration allows for the increased suppression of multiple noise sources and for the detection of stochastic gravitational wave signals. The mission will offer a strain sensitivity of {<10^{-18}/sqrt{Hz}} in the 50mHz-10Hz frequency range, providing access to a rich scientific region with substantial discovery potential. This band is not currently addressed with the LIGO, VIRGO, or LISA instruments. We analyze systematic backgrounds that are relevant to the mission and discuss how they can be mitigated at the required levels. Some of these effects do not appear to have been considered previously in the context of atom interferometry, and we therefore expect that our analysis will be broadly relevant to atom interferometric precision measurements. Finally, we present a brief conceptual overview of shorter-baseline ({lesssim100 m}) atom interferometer configurations that could be deployed as proof-of-principle instruments on the International Space Station (AGIS-ISS) or an independent satellite.

Chemistry of the sea surface microlayer. 1. Fabrication and testing of the sampler

Digital Repository Service at National Institute of Oceanography (India)

Singbal, S.Y.S.; Narvekar, P.V.

A screen sampler fabricated to study the sea surface microlayer (SML) has been described. The screen sampler was tested in the Mandovi estuary and adjacent waters. Physico-chemical parameters of the subsurface waters from a depth of 25 cm was also...

Dynamic properties of a dirt and a synthetic equine racetrack surface measured by a track-testing device.

Science.gov (United States)

Setterbo, J J; Fyhrie, P B; Hubbard, M; Upadhyaya, S K; Stover, S M

2013-01-01

Racetrack surface is a risk factor for Thoroughbred racehorse injury and death that can be engineered and managed. To investigate the relationship between surface and injury, the mechanical behaviour of dirt and synthetic track surfaces must be quantified. To compare dynamic properties of a dirt and a synthetic surface in situ using a track-testing device designed to simulate equine hoof impact; and to determine the effects of impact velocity, impact angle and repeated impact on dynamic surface behaviour. A track-testing device measured force and displacement during impact into a dirt and a synthetic surface at 3 impact velocities (1.91, 2.30, 2.63 m/s), 2 impact angles (0°, 20° from vertical), and 2 consecutive impacts (initial, repeat). Surfaces were measured at 3 locations/day for 3 days. The effects of surface type, impact velocity, impact angle and impact number on dynamic surface properties were assessed using analysis of variance. Synthetic surface maximum forces, load rates and stiffnesses were 37-67% of dirt surface values. Surfaces were less stiff with lower impact velocities, angled impacts and initial impacts. The magnitude of differences between dirt and synthetic surfaces increased for repeat impacts and higher impact velocities. The synthetic surface was generally softer than the dirt surface. Greatly increased hardness for repeat impacts corroborates the importance of maintenance. Results at different impact velocities suggest that surface differences will persist at higher impact velocities. For both surfaces it is clearly important to prevent horse exposure to precompacted surfaces, particularly during high-speed training when the surface has already been trampled. These data should be useful in coordinating racetrack surface management with racehorse training to prevent injuries. © 2012 EVJ Ltd.

Effect of Nonlinearity by the Amplitude Variation in coherent transmission in Laser Heterodyne Interferometric

International Nuclear Information System (INIS)

Chen, H F; Ding, X M; Zhong, Z; Xie, Z L; Yue, H

2006-01-01

To reduce the nonlinearity of nanometer measurement in laser heterodyne interferometric, the influence mechanics of the amplitude variation in coherent transmission upon nonlinearity must be confirmed. Based on the mechanics of nonlinearity, the models about how first-harmonic and second-harmonic nonlinearity caused by the amplitude variation in coherent transmission are proposed. The emulation result shows that different amplitude between measurement arm and reference arm increases the first-harmonic nonlinearity when laser beams nonorthogonality errors exist, but it doesn't change the relationship between nonlinearity and half wavelength. When the rotation angle error β of polarizing beam splitter (PBS) exists, amplitude variation only affects the first-harmonic nonlinearity. With a constant rotation angle of PBS β = 4 0 , when the amplitude factor of measurement arm reduces from 1 to 0.6, the nonlinearity increases from 0.25 nm to 3.81 nm, and the nonlinearity is simple superposition of first-harmonic and second-harmonic. Theoretic analysis and emulation show that the reduction of amplitude variation in coherent transmission can reduce influence on nonlinearity

Interferometric characterization of the structured polarized light beam produced by the conical refraction phenomenon.

Science.gov (United States)

Peinado, Alba; Turpin, Alex; Iemmi, Claudio; Márquez, Andrés; Kalkandjiev, Todor K; Mompart, Jordi; Campos, Juan

2015-07-13

The interest on the conical refraction (CR) phenomenon in biaxial crystals has revived in the last years due to its prospective for generating structured polarized light beams, i.e. vector beams. While the intensity and the polarization structure of the CR beams are well known, an accurate experimental study of their phase structure has not been yet carried out. We investigate the phase structure of the CR rings by means of a Mach-Zehnder interferometer while applying the phase-shifting interferometric technique to measure the phase at the focal plane. In general the two beams interfering correspond to different states of polarization (SOP) which locally vary. To distinguish if there is an additional phase added to the geometrical one we have derived the appropriate theoretical expressions using the Jones matrix formalism. We demonstrate that the phase of the CR rings is equivalent to that one introduced by an azimuthally segmented polarizer with CR-like polarization distribution. Additionally, we obtain direct evidence that the Poggendorff dark ring is an annular singularity, with a π phase change between the inner and outer bright rings.

Monitoring Bare Soil Freeze–Thaw Process Using GPS-Interferometric Reflectometry: Simulation and Validation

Directory of Open Access Journals (Sweden)

Xuerui Wu

2017-12-01

Full Text Available Frozen soil and permafrost affect ecosystem diversity and productivity as well as global energy and water cycles. Although some space-based Radar techniques or ground-based sensors can monitor frozen soil and permafrost variations, there are some shortcomings and challenges. For the first time, we use GPS-Interferometric Reflectometry (GPS-IR to monitor and investigate the bare soil freeze–thaw process as a new remote sensing tool. The mixed-texture permittivity models are employed to calculate the frozen and thawed soil permittivities. When the soil freeze/thaw process occurs, there is an abrupt change in the soil permittivity, which will result in soil scattering variations. The corresponding theoretical simulation results from the forward GPS multipath simulator show variations of GPS multipath observables. As for the in-situ measurements, virtual bistatic radar is employed to simplify the analysis. Within the GPS-IR spatial resolution, one SNOTEL site (ID 958 and one corresponding PBO (plate boundary observatory GPS site (AB33 are used for analysis. In 2011, two representative days (frozen soil on Doy of Year (DOY 318 and thawed soil on DOY 322 show the SNR changes of phase and amplitude. The GPS site and the corresponding SNOTEL site in four different years are analyzed for comparisons. When the soil freeze/thaw process occurred and no confounding snow depth and soil moisture effects existed, it exhibited a good absolute correlation (|R| = 0.72 in 2009, |R| = 0.902 in 2012, |R| = 0.646 in 2013, and |R| = 0.7017 in 2014 with the average detrended SNR data. Our theoretical simulation and experimental results demonstrate that GPS-IR has potential for monitoring the bare soil temperature during the soil freeze–thaw process, while more test works should be done in the future. GNSS-R polarimetry is also discussed as an option for detection. More retrieval work about elevation and polarization combinations are the focus of future development.

Aircraft control surface failure detection and isolation using the OSGLR test. [orthogonal series generalized likelihood ratio

Science.gov (United States)

Bonnice, W. F.; Motyka, P.; Wagner, E.; Hall, S. R.

1986-01-01

The performance of the orthogonal series generalized likelihood ratio (OSGLR) test in detecting and isolating commercial aircraft control surface and actuator failures is evaluated. A modification to incorporate age-weighting which significantly reduces the sensitivity of the algorithm to modeling errors is presented. The steady-state implementation of the algorithm based on a single linear model valid for a cruise flight condition is tested using a nonlinear aircraft simulation. A number of off-nominal no-failure flight conditions including maneuvers, nonzero flap deflections, different turbulence levels and steady winds were tested. Based on the no-failure decision functions produced by off-nominal flight conditions, the failure detection and isolation performance at the nominal flight condition was determined. The extension of the algorithm to a wider flight envelope by scheduling on dynamic pressure and flap deflection is examined. Based on this testing, the OSGLR algorithm should be capable of detecting control surface failures that would affect the safe operation of a commercial aircraft. Isolation may be difficult if there are several surfaces which produce similar effects on the aircraft. Extending the algorithm over the entire operating envelope of a commercial aircraft appears feasible.

Microprocessor-controlled surface testing

Energy Technology Data Exchange (ETDEWEB)

Droscha, H

1982-09-01

For the quality inspection on continuous flow material webs with transverse scanning laser beam, the microprocessor control, realized now for the first time in combination with appropriate units, shows a considerable progress. Thanks to the here used electronics, surface errors can be localized within the web according to their x-y-position, quantitative analysis can be carried out and automatic sorting and registration functions can be used.

Fundamental study of microelectronic chip response under laser ultrasonic-interferometric inspection using C-scan method

Science.gov (United States)

Yang, Lei; Gong, Jie; Ume, I. Charles

2014-02-01

In modern surface mount packaging technologies, such as flip chips, chip scale packages, and ball grid arrays(BGA), chips are attached to the substrates/printed wiring board (PWB) using solder bump interconnections. The quality of solder bumps between the chips and the substrate/board is difficult to inspect. Laser ultrasonic-interferometric technique was proved to be a promising approach for solder bump inspection because of its noncontact and nondestructive characteristics. Different indicators extracted from received signals have been used to predict the potential defects, such as correlation coefficient, error ratio, frequency shifting, etc. However, the fundamental understanding of the chip behavior under laser ultrasonic inspection is still missing. Specifically, it is not sure whether the laser interferometer detected out-of-plane displacements were due to wave propagation or structural vibration when the chip was excited by pulsed laser. Plus, it is found that the received signals are chip dependent. Both challenges impede the interpretation of acquired signals. In this paper, a C-scan method was proposed to study the underlying phenomenon during laser ultrasonic inspection. The full chip was inspected. The response of the chip under laser excitation was visualized in a movie resulted from acquired signals. Specifically, a BGA chip was investigated to demonstrate the effectiveness of this method. By characterizing signals using discrete wavelet transform(DWT), both ultrasonic wave propagation and vibration were observed. Separation of them was successfully achieved using ideal band-pass filter and visualized in resultant movies, too. The observed ultrasonic waves were characterized and their respective speeds were measured by applying 2-D FFT. The C-scan method, combined with different digital signal processing techniques, was proved to be an very effective methodology to learn the behavior of chips under laser excitation. This general procedure can be

Laboratory coupling tests for optimum land streamer design over sand dunes surface

KAUST Repository

Almalki, Hashim

2012-02-26

The cost of data acquisition in land is becoming a major issue as we strive to cover larger areas with seismic surveys at high resolution. Over sand dunes the problem is compounded by the week coupling obtain using geophones, which often forces us to bury the phone. A major challenge is designing such a land streamer system that combines durability, mobility and the required coupling. We share a couple of such designs and discuss the merits behind such designs and test their capability. The testing includes, the level of coupling, mobility and drag over sand surfaces. For specific designs loose sand can accumulate inside the steamer reducing its mobility. On the other hand, poor coupling will attenuate the high frequencies and cause an effective delay in the signal. The weight of the streamer is also an important factor in both mobility and coupling as it adds to the coupling it reduces the mobility of the streamer. We study the impact of weight and base plate surface area on the seismic signal quality, as well as the friction factor of different designs.

Multidimensional gray-wavelet processing in interferometric fiber-optic gyroscopes

International Nuclear Information System (INIS)

Yang, Yi; Wang, Zinan; Peng, Chao; Li, Zhengbin

2013-01-01

A multidimensional signal processing method for a single interferometric fiber-optic gyroscope (IFOG) is proposed, to the best of our knowledge, for the first time. The proposed method, based on a novel IFOG structure with quadrature demodulation, combines a multidimensional gray model (GM) and a wavelet compression technique for noise suppression and sensitivity enhancement. In the IFOG, two series of measured rotation rates are obtained simultaneously: an in-phase component and a quadrature component. Together with the traditionally measured rate, the three measured rates are processed by the combined gray-wavelet method. Simulations show that the intensity noise and non-reciprocal phase fluctuations are effectively suppressed by this method. Experimental comparisons with a one-dimensional GM(1, 1) model show that the proposed three-dimensional method achieves much better denoising performance. This advantage is validated by the Allan variance analysis: in a low-SNR (signal-to-noise ratio) experiment, our method reduces the angle random walk (ARW) and the bias instability (BI) from 1 × 10 −2  deg h −1/2 and 3 × 10 −2  deg h −1 to 1 × 10 −3  deg h −1/2 and 3 × 10 −3  deg h −1 , respectively; in a high-SNR experiment, our method reduces the ARW and the BI from 9 × 10 −4  deg h −1/2 and 5 × 10 −3  deg h −1 to 4 × 10 −4  deg h −1/2 and 3 × 10 −3  deg h −1 , respectively. Further, our method increases the dimension of the state-of-the-art IFOG technique from one to three, thus obtaining higher IFOG sensitivity and stability by exploiting the increase in available information. (paper)

Multidimensional gray-wavelet processing in interferometric fiber-optic gyroscopes

Science.gov (United States)

Yang, Yi; Wang, Zinan; Peng, Chao; Li, Zhengbin

2013-11-01

A multidimensional signal processing method for a single interferometric fiber-optic gyroscope (IFOG) is proposed, to the best of our knowledge, for the first time. The proposed method, based on a novel IFOG structure with quadrature demodulation, combines a multidimensional gray model (GM) and a wavelet compression technique for noise suppression and sensitivity enhancement. In the IFOG, two series of measured rotation rates are obtained simultaneously: an in-phase component and a quadrature component. Together with the traditionally measured rate, the three measured rates are processed by the combined gray-wavelet method. Simulations show that the intensity noise and non-reciprocal phase fluctuations are effectively suppressed by this method. Experimental comparisons with a one-dimensional GM(1, 1) model show that the proposed three-dimensional method achieves much better denoising performance. This advantage is validated by the Allan variance analysis: in a low-SNR (signal-to-noise ratio) experiment, our method reduces the angle random walk (ARW) and the bias instability (BI) from 1 × 10-2 deg h-1/2 and 3 × 10-2 deg h-1 to 1 × 10-3 deg h-1/2 and 3 × 10-3 deg h-1, respectively; in a high-SNR experiment, our method reduces the ARW and the BI from 9 × 10-4 deg h-1/2 and 5 × 10-3 deg h-1 to 4 × 10-4 deg h-1/2 and 3 × 10-3 deg h-1, respectively. Further, our method increases the dimension of the state-of-the-art IFOG technique from one to three, thus obtaining higher IFOG sensitivity and stability by exploiting the increase in available information.

High-Repetition-Rate Interferometric Rayleigh Scattering for Velocity, Density, and Temperature Meas, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Large ground-test facilities, which simulate real flow conditions from subsonic to hypersonic, are used extensively to generate forces and moments as well as surface...

A novel test method for quantifying surface tack of polypropylene compound surfaces

Directory of Open Access Journals (Sweden)

2011-11-01

Full Text Available While adhesiveness is required for polymer surfaces in special applications, tacky surfaces are generally undesirable in many applications like automotive interior parts. The tackiness of polymer surface results from a combination of composition and additivation, and it can change significantly in natural or accelerated ageing. Since there is no established, uniform method to characterize surface tack, the major focus of the present work was on the development of an objective quantification method. A setup having a soft die tip attached to a standard tensile tester was developed aiming for correlation to the human sense of touch. Three different model thermoplastic polyolefin (TPO compound formulations based on a high-impact isotactic polypropylene (iPP composition with varying amounts and types of anti-scratch additives were used for these investigations. As the surface tack phenomenon is related to ageing and weathering, the material’s examination was also performed after various intervals of weathering. The developed method allows a fast assessment of the effect of polymer composition variations and different additive formulations on surface tack and gives identical rankings as the standardized haptic panel.

Transmitted wavefront testing with large dynamic range based on computer-aided deflectometry

Science.gov (United States)

Wang, Daodang; Xu, Ping; Gong, Zhidong; Xie, Zhongmin; Liang, Rongguang; Xu, Xinke; Kong, Ming; Zhao, Jun

2018-06-01

The transmitted wavefront testing technique is demanded for the performance evaluation of transmission optics and transparent glass, in which the achievable dynamic range is a key issue. A computer-aided deflectometric testing method with fringe projection is proposed for the accurate testing of transmitted wavefronts with a large dynamic range. Ray tracing of the modeled testing system is carried out to achieve the virtual ‘null’ testing of transmitted wavefront aberrations. The ray aberration is obtained from the ray tracing result and measured slope, with which the test wavefront aberration can be reconstructed. To eliminate testing system modeling errors, a system geometry calibration based on computer-aided reverse optimization is applied to realize accurate testing. Both numerical simulation and experiments have been carried out to demonstrate the feasibility and high accuracy of the proposed testing method. The proposed testing method can achieve a large dynamic range compared with the interferometric method, providing a simple, low-cost and accurate way for the testing of transmitted wavefronts from various kinds of optics and a large amount of industrial transmission elements.

Numerical modeling of the Near Surface Test Facility No. 1 and No. 2 heater tests

International Nuclear Information System (INIS)

Hocking, G.; Williams, J.; Boonlualohr, P.; Mathews, I.; Mustoe, G.

1981-01-01

Thermomechanical predictive calculations have been undertaken for two full scale heater tests No. 1 and No. 2 at the Near Surface Test Facility (NSTF) at Hanford, Washington. Numerical predictions were made of the basaltic rock response involving temperatures, displacements, strains and stresses due to energizing the electrical heaters. The basalt rock mass was modeled as an isotropic thermal material but with temperature dependent thermal conductivity, specific heat and thermal expansion. The fractured nature of the basalt necessitated that it be modeled as a cross anisotropic medium with a bi-linear locking stress strain relationship. The cross-anisotropic idealization was selected after characterization studies indicated that a vertical columnar structure persisted throughout the test area and no major throughgoing discontinuities were present. The deformational properties were determined from fracture frequency and orientation, joint deformational data, Goodman Jack results and two rock mass classification schemes. Similar deformational moduli were determined from these techniques, except for the Goodman Jack results. The finite element technique was utilized for both the non-linear thermal and mechanical computations. An incremental stiffness method with residual force correction was employed to solve the non-linear problem by piecewise linearization. Two and three dimensional thermomechanical scoping calculations were made to assess the significance of various parameters and associated errors with geometrical idealizations. Both heater tests were modeled as two dimensional axisymmetric geometry with water assumed to be absent. Instrument response was predicted for all of the thermocouples, extensometers, USBM borehole deformation and IRAD gages for the entire duration of both tests

Stress studies in EFG

Science.gov (United States)

1983-01-01

Stress distributions were calculated for a creep law to predict a rate of plastic deformation. The expected reduction in stresses is obtained. Improved schemes for calculating growth system temperature distributions were evaluated. Temperature field modeling examined the possibility of using horizontal temperature gradients to influence stress distribution in ribbon. The defect structure of 10 cm wide ribbon grown in the cartridge system was examined. A new feature is identified from an examination of cross sectional micrographs. It consists of high density dislocation bands extending through the ribbon thickness. A four point bending apparatus was constructed for high temperature study of the creep response of silicon, to be used to generate defects for comparison with as grown defects in ribbon. The feasibility of laser interferometric techniques for sheet residual stress distribution measurement is examined. The mathematical formalism for calculating residual stress from changes in surface topology caused by an applied stress in a rectangular specimen was developed, and the system for laser interferometric measurement to obtain surface topology data was tested on CZ silicon.

Building blocks for future detectors: Silicon test masses and 1550 nm laser light

International Nuclear Information System (INIS)

Schnabel, R; Britzger, M; Burmeister, O; Danzmann, K; Duck, J; Eberle, T; Friedrich, D; Luck, H; Mehmet, M; Steinlechner, S; Willke, B; Brueckner, F; Nawrodt, R

2010-01-01

Current interferometric gravitational wave detectors use the combination of quasi-monochromatic, continuous-wave laser light at 1064 nm and fused silica test masses at room temperature. Detectors of the third generation, such as the Einstein-Telescope, will involve a considerable sensitivity increase. The combination of 1550 nm laser radiation and crystalline silicon test masses at low temperatures might be important ingredients in order to achieve the sensitivity goal. Here we compare some properties of the fused silica and silicon test mass materials relevant for decreasing the thermal noise in future detectors as well as the recent technology achievements in the preparation of laser radiation at 1064 nm and 1550 nm relevant for decreasing the quantum noise. We conclude that silicon test masses and 1550 nm laser light have the potential to form the future building blocks of gravitational wave detection.

Modelling of mid-infrared interferometric signature of hot exozodiacal dust emission

Science.gov (United States)

Kirchschlager, Florian; Wolf, Sebastian; Brunngräber, Robert; Matter, Alexis; Krivov, Alexander V.; Labdon, Aaron

2018-01-01

Hot exozodiacal dust emission was detected in recent surveys around two dozen main-sequence stars at distances of less than 1 au using the H- and K-band interferometry. Due to the high contrast as well as the small angular distance between the circumstellar dust and the star, direct observation of this dust component is challenging. An alternative way to explore the hot exozodiacal dust is provided by mid-infrared interferometry. We analyse the L, M and N bands interferometric signature of this emission in order to find stronger constraints for the properties and the origin of the hot exozodiacal dust. Considering the parameters of nine debris disc systems derived previously, we model the discs in each of these bands. We find that the M band possesses the best conditions to detect hot dust emission, closely followed by L and N bands. The hot dust in three systems - HD 22484 (10 Tau), HD 102647 (β Leo) and HD 177724 (ζ Aql) - shows a strong signal in the visibility functions, which may even allow one to constrain the dust location. In particular, observations in the mid-infrared could help to determine whether the dust piles up at the sublimation radius or is located at radii up to 1 au. In addition, we explore observations of the hot exozodiacal dust with the upcoming mid-infrared interferometer Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) at the Very Large Telescope Interferometer.

Remote surface testing and inspection vehicle

International Nuclear Information System (INIS)

Hyde, E.A.; Goldsmith, H.A.; Proudlove, M.J.

1981-01-01

A remotely controlled vehicle capable of roving over the outer surface of a nuclear reactor primary vessel carrying inspection instrumentation. The vehicle comprises an elongate bridge having a pair of suction support pads. Each pad carries gas thrusters for acting in opposition to the suction effort thereby to reduce adherence of the pads and enable displacement of the vehicle over the surface. The vehicle is supported by a services conducting umbilical. (author)

Advances in the application of holography for NDE

Science.gov (United States)

Sciammarella, C. A.

1985-01-01

The basic methodology of holographic interferometry in nondestructive testing (NDT) applications are described. Applications to crack detection in ceramic materials, including a crack 50 microns deep in a turbine blade, are discussed in detail. The theoretical principles of holographic interferometry are explained, and a general description of a holographic interferometric recording system is given. A nondestructive interferometric technique for measuring the gradual erosion of calcareous stones exposed to acid rain is also presented. Detailed line drawings illustrating the hologram recording and interferometric fringe pattern analysis elements in an interferometric holographic NDT device are provided.

Basic research into eddy current testing of austenetic weld joints and surface claddings

International Nuclear Information System (INIS)

Meier, W.

1976-01-01

The result of research work has shown that the eddy-current testing method can be used for austenetic steel up to 10 mm thick to detect cracks in the material. An exception to this are laminations if they are parallel to the surface. Cracks in the various geometrical positions in the test specimen produce different results in the x-y plot. They are influenced by the direction of the material cracks. Research into the influence the geometric parameters have on the indications shows that the eddy-current method provides clearer interpretations of material cracks than any other non-destructive test method known. (orig.) [de

Topics in LIGO-related physics: Interferometric speed meters and tidal work

Science.gov (United States)

Purdue, Patricia Marie

In the quest to develop viable designs for third-generation interferometric gravitational-wave detectors (such as the Laser Interferometer Gravitational-Wave Observatory, LIGO), one strategy is monitoring the relative momentum or speed of the test-mass mirrors, rather than monitoring their relative position. The most straightforward design for a speed-meter interferometer that accomplishes this is analyzed in Chapter 2. It is shown that in principle this design can beat the standard quantum limit (SQL) by an arbitrarily large amount, over an arbitrarily wide range of frequencies. However, in practice, this specific speed meter requires exorbitantly high input light power. Chapter 3 proposes a more sophisticated version of a speed meter. This new design requires modest input power and appears to be a fully practical candidate for third-generation detectors. It can beat the SQL over a broad range of frequencies (˜10 to 100 Hz in practice) by a factor h/hSQL ˜ WSQLcirc/Wc irc . Here Wcirc is the light power circulating in the interferometer arms and WSQL ≃ 800 kW is the circulating power required to beat the SQL at 100 Hz. If squeezed vacuum (with a power-squeeze factor e-2 R) is injected into the interferometer's output port, the SQL can be beat with less laser power: h/h SQL ˜ WSQLcirc/Wc irce2R . For realistic parameters (e2 R ≃ 10 and Wcirc ≃ 800 kW), the SQL can be beat by a factor ˜3 from 10 to 100 Hz. By performing frequency-dependent homodyne detection on the output (using two kilometer-scale filter cavities), one can markedly improve the interferometer's sensitivity at frequencies above 100 Hz. Chapter 4 is a contribution to the foundations for analyzing sources of gravitational waves. Specifically, it presents an analysis of the tidal work done on a self-gravitating body in an external tidal field. By examining the change in the mass-energy of the body as a result of the tidal field, it is shown that the work done is gauge invariant, while the body

Source signature estimation from multimode surface waves via mode-separated virtual real source method

Science.gov (United States)

Gao, Lingli; Pan, Yudi

2018-05-01

The correct estimation of the seismic source signature is crucial to exploration geophysics. Based on seismic interferometry, the virtual real source (VRS) method provides a model-independent way for source signature estimation. However, when encountering multimode surface waves, which are commonly seen in the shallow seismic survey, strong spurious events appear in seismic interferometric results. These spurious events introduce errors in the virtual-source recordings and reduce the accuracy of the source signature estimated by the VRS method. In order to estimate a correct source signature from multimode surface waves, we propose a mode-separated VRS method. In this method, multimode surface waves are mode separated before seismic interferometry. Virtual-source recordings are then obtained by applying seismic interferometry to each mode individually. Therefore, artefacts caused by cross-mode correlation are excluded in the virtual-source recordings and the estimated source signatures. A synthetic example showed that a correct source signature can be estimated with the proposed method, while strong spurious oscillation occurs in the estimated source signature if we do not apply mode separation first. We also applied the proposed method to a field example, which verified its validity and effectiveness in estimating seismic source signature from shallow seismic shot gathers containing multimode surface waves.

Research on the method of improving the accuracy of CMM (coordinate measuring machine) testing aspheric surface

Science.gov (United States)

Cong, Wang; Xu, Lingdi; Li, Ang

2017-10-01

Large aspheric surface which have the deviation with spherical surface are being used widely in various of optical systems. Compared with spherical surface, Large aspheric surfaces have lots of advantages, such as improving image quality, correcting aberration, expanding field of view, increasing the effective distance and make the optical system compact, lightweight. Especially, with the rapid development of space optics, space sensor resolution is required higher and viewing angle is requred larger. Aspheric surface will become one of the essential components in the optical system. After finishing Aspheric coarse Grinding surface profile error is about Tens of microns[1].In order to achieve the final requirement of surface accuracy,the aspheric surface must be quickly modified, high precision testing is the basement of rapid convergence of the surface error . There many methods on aspheric surface detection[2], Geometric ray detection, hartmann detection, ronchi text, knifeedge method, direct profile test, interferometry, while all of them have their disadvantage[6]. In recent years the measure of the aspheric surface become one of the import factors which are restricting the aspheric surface processing development. A two meter caliber industrial CMM coordinate measuring machine is avaiable, but it has many drawbacks such as large detection error and low repeatability precision in the measurement of aspheric surface coarse grinding , which seriously affects the convergence efficiency during the aspherical mirror processing. To solve those problems, this paper presents an effective error control, calibration and removal method by calibration mirror position of the real-time monitoring and other effective means of error control, calibration and removal by probe correction and the measurement mode selection method to measure the point distribution program development. This method verified by real engineer examples, this method increases the original industrial

Design data sheets Near-Surface Test Facility Bottom Loading Transporter (BLT): Title 1

International Nuclear Information System (INIS)

Young, G.M.

1979-01-01

This document is an accumulation of all the Design Data Sheets relative to the handling equipment in the transporter for the Near-Surface Test Facility. The Data Sheets are in ascending numerical order. Each Data Sheet, regardless of the number of pages, shall stand by itself within this document

Mathematical modelling of ultrasonic testing of components with defects close to a non-planar surface

International Nuclear Information System (INIS)

Westlund, Jonathan; Bostroem, Anders

2011-05-01

Nondestructive testing with ultrasound is a standard procedure in the nuclear power industry. To develop and qualify the methods extensive experimental work with test blocks is usually required. This can be very time-consuming and costly and it also requires a good physical intuition of the situation. A reliable mathematical model of the testing situation can, therefore, be very valuable and cost-effective as it can reduce experimental work significantly. A good mathematical model enhances the physical intuition and is very useful for parametric studies, as a pedagogical tool, and for the qualification of procedures and personnel. The aim of the present report is to describe work that has been performed to model ultrasonic testing of components that contain a defect close to a nonplanar surface. For nuclear power applications this may be a crack or other defect on the inside of a pipe with a diameter change or connection. This is an extension of the computer program UTDefect, which previously only admits a planar back surface (which is often applicable also to pipes if the pipe diameter is large enough). The problems are investigated in both 2D and 3D, and in 2D both the simpler anti-plane (SH) and the in-plane (P-SV) problem are studied. The 2D investigations are primarily solved to get a 'feeling' for the solution procedure, the discretizations, etc. In all cases an integral equation approach with a Green's function in the kernel is taken. The nonplanar surface is treated by the boundary element method (BEM) where a division of the surface is made in small elements. The defects are mainly cracks, strip-like (in 2D) or rectangular (in 3D), and these are treated with more analytical methods. In 2D also more general defects are treated with the help of their transition (T) matrix. As in other parts of UTDefect the ultrasonic probes in transmission and reception are included in the model. In 3D normalization by a side drilled hole is possible. Some numerical results

Development and Evaluation of the Interferometric Monitor for Greenhouse Gases: a High-throughput Fourier-transform Infrared Radiometer for Nadir Earth Observation

Science.gov (United States)

Kobayashi, Hirokazu; Shimota, Akiro; Kondo, Kayoko; Okumura, Eisuke; Kameda, Yoshihiko; Shimoda, Haruhisa; Ogawa, Toshihiro

1999-11-01

The interferometric monitor for greenhouse gases (IMG) was the precursor of the high-resolution Fourier-transform infrared radiometer (FTIR) onboard a satellite for observation of the Earth. The IMG endured the stress of a rocket launch, demonstrating that the high-resolution, high-throughput spectrometer is indeed feasible for use onboard a satellite. The IMG adopted a newly developed lubricant-free magnetic suspension mechanism and a dynamic alignment system for the moving mirror with a maximum traveling distance of 10 cm. We present the instrumentation of the IMG, characteristics of the movable mirror drive system, and the evaluation results of sensor specifications during space operation.

Strain transfer through film-substrate interface and surface curvature evolution during a tensile test

Science.gov (United States)

He, Wei; Han, Meidong; Goudeau, Philippe; Bourhis, Eric Le; Renault, Pierre-Olivier; Wang, Shibin; Li, Lin-an

2018-03-01

Uniaxial tensile tests on polyimide-supported thin metal films are performed to respectively study the macroscopic strain transfer through an interface and the surface curvature evolution. With a dual digital image correlation (DIC) system, the strains of the film and the substrate can be simultaneously measured in situ during the tensile test. For the true strains below 2% (far beyond the films' elastic limit), a complete longitudinal strain transfer is present irrespective of the film thickness, residual stresses and microstructure. By means of an optical surface profiler, the three-dimensional (3D) topography of film surface can be obtained during straining. As expected, the profile of the specimen center remains almost flat in the tensile direction. Nevertheless, a relatively significant curvature evolution (of the same order with the initial curvature induced by residual stresses) is observed along the transverse direction as a result of a Poisson's ratio mismatch between the film and the substrate. Furthermore, finite element method (FEM) has been performed to simulate the curvature evolution considering the geometric nonlinearity and the perfect strain transfer at the interface, which agrees well with the experimental results.

Characterisation and Testing of Multifunctional Surfaces