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Sample records for absolute thickness measurements

  1. Absolute Measurements of Radiation Damage in Nanometer Thick Films

    PubMed Central

    Alizadeh, Elahe; Sanche, Léon

    2013-01-01

    We address the problem of absolute measurements of radiation damage in films of nanometer thicknesses. Thin films of DNA (~ 2–160nm) are deposited onto glass substrates and irradiated with varying doses of 1.5 keV X-rays under dry N2 at atmospheric pressure and room temperature. For each different thickness, the damage is assessed by measuring the loss of the supercoiled configuration as a function of incident photon fluence. From the exposure curves, the G-values are deduced, assuming that X-ray photons interacting with DNA, deposit all of their energy in the film. The results show that the G-value (i.e., damage per unit of deposited energy) increases with film thickness and reaches a plateau at 30±5 nm. This thickness dependence provides a correction factor to estimate the actual G-value for films with thicknesses below 30nm thickness. Thus, the absolute values of damage can be compared with that of films of any thickness under different experimental conditions. PMID:22562941

  2. Absolute thickness metrology with submicrometer accuracy using a low-coherence distance measuring interferometer.

    PubMed

    Zhao, Yang; Schmidt, Greg; Moore, Duncan T; Ellis, Jonathan D

    2015-09-01

    Absolute physical thickness across the sample aperture is critical in determining the index of a refraction profile from the optical path length profile for gradient index (GRIN) materials, which have a designed inhomogeneous refractive index. Motivated by this application, instrumentation was established to measure the absolute thickness of samples with nominally plane-parallel surfaces up to 50 mm thick. The current system is capable of measuring absolute thickness with 120 nm (1σ) repeatability and submicrometer expanded measurement uncertainty. Beside GRIN materials, this method is also capable of measuring other inhomogeneous and opaque materials.

  3. An ultrasonic system for measurement of absolute myocardial thickness using a single transducer.

    PubMed

    Pitsillides, K F; Longhurst, J C

    1995-03-01

    We have developed an ultrasonic instrument that can measure absolute regional myocardial wall motion throughout the cardiac cycle using a single epicardial piezoelectric transducer. The methods in place currently that utilize ultrasound to measure myocardial wall thickness are the transit-time sonomicrometer (TTS) and, more recently, the Doppler echo displacement method. Both methods have inherent disadvantages. To address the need for an instrument that can measure absolute dimensions of myocardial wall at any depth, an ultrasonic single-crystal sonomicrometer (SCS) system was developed. This system can identify and track the boundary of the endocardial muscle-blood interface. With this instrument, it is possible to obtain, from a single epicardial transducer, measurement of myocardial wall motion that is calibrated in absolute dimensional units. The operating principles of the proposed myocardial dimension measurement system are as follows. A short duration ultrasonic burst having a frequency of 10 MHz is transmitted from the piezoelectric transducer. Reflected echoes are sampled at two distinct time intervals to generate reference and interface sample volumes. During steady state, the two sample volumes are adjusted so that the reference volume remains entirely within the myocardium, whereas half of the interface sampled volume is located within the myocardium. After amplification and filtering, the true root mean square values of both signals are compared and an error signal is generated. A closed-loop circuit uses the integrated error signal to continuously adjust the position of the two sample volumes. We have compared our system in vitro against a known signal and in vivo against the two-crystal TTS system during control, suppression (ischemia), and enhancement (isoproterenol) of myocardial function. Results were obtained in vitro for accuracy (> 99%), signal linearity (r = 0.99), and frequency response to heart rates > 450 beats/min, and in vivo data were

  4. Absolute measurements of the uranium concentration in thick samples using fission-track detectors

    NASA Astrophysics Data System (ADS)

    Enkelmann, Eva; Jonckheere, Raymond; Ratschbacher, Lothar

    2005-04-01

    We propose an improved equation for calculating the uranium concentration in thick samples based on induced fission-track counts in an external detector that takes into consideration (1) the fission-fragment ranges in the sample and external detector, (2) the etchable track length and (3) the track counting efficiency in the external detector. The values of these parameters have been determined by calculation and experiment and are shown to have a significant effect on the calculated uranium concentrations. The new equation was tested by calculating the uranium concentrations in standard uranium glasses (CN-5; IRMM-540R) and apatite samples (Durango; horse tooth) in which the uranium content was also determined with independent methods (INAA; ENAA; TIMS). The results show that: (1) accurate measurements with the fission-track method are feasible within a broad range of uranium concentrations and (2) uranium determinations based on standards are only accurate if the standard and sample are made of the same material. Because the absolute fission-tack dating method is also based on accurate thermal neutron fluence measurements and similar correction factors for the track registration and counting efficiencies, this study provides a strong endorsement for the fact that absolute fission-track ages are accurate.

  5. Absolute Thickness Measurements on Coatings Without Prior Knowledge of Material Properties Using Terahertz Energy

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Cosgriff, Laura M.; Harder, Bryan; Zhu, Dongming; Martin, Richard E.

    2013-01-01

    This study investigates the applicability of a novel noncontact single-sided terahertz electromagnetic measurement method for measuring thickness in dielectric coating systems having either dielectric or conductive substrate materials. The method does not require knowledge of the velocity of terahertz waves in the coating material. The dielectric coatings ranged from approximately 300 to 1400 m in thickness. First, the terahertz method was validated on a bulk dielectric sample to determine its ability to precisely measure thickness and density variation. Then, the method was studied on simulated coating systems. One simulated coating consisted of layered thin paper samples of varying thicknesses on a ceramic substrate. Another simulated coating system consisted of adhesive-backed Teflon adhered to conducting and dielectric substrates. Alumina samples that were coated with a ceramic adhesive layer were also investigated. Finally, the method was studied for thickness measurement of actual thermal barrier coatings (TBC) on ceramic substrates. The unique aspects and limitations of this method for thickness measurements are discussed.

  6. Absolute Standards for Climate Measurements

    NASA Astrophysics Data System (ADS)

    Leckey, J.

    2016-10-01

    In a world of changing climate, political uncertainty, and ever-changing budgets, the benefit of measurements traceable to SI standards increases by the day. To truly resolve climate change trends on a decadal time scale, on-orbit measurements need to be referenced to something that is both absolute and unchanging. One such mission is the Climate Absolute Radiance and Refractivity Observatory (CLARREO) that will measure a variety of climate variables with an unprecedented accuracy to definitively quantify climate change. In the CLARREO mission, we will utilize phase change cells in which a material is melted to calibrate the temperature of a blackbody that can then be observed by a spectrometer. A material's melting point is an unchanging physical constant that, through a series of transfers, can ultimately calibrate a spectrometer on an absolute scale. CLARREO consists of two primary instruments: an infrared (IR) spectrometer and a reflected solar (RS) spectrometer. The mission will contain orbiting radiometers with sufficient accuracy to calibrate other space-based instrumentation and thus transferring the absolute traceability. The status of various mission options will be presented.

  7. Lead Thickness Measurements

    SciTech Connect

    Rucinski, R.; /Fermilab

    1998-02-16

    The preshower lead thickness applied to the outside of D-Zero's superconducting solenoid vacuum shell was measured at the time of application. This engineering documents those thickness measurements. The lead was ordered in sheets 0.09375-inch and 0.0625-inch thick. The tolerance on thickness was specified to be +/- 0.003-inch. The sheets all were within that thickness tolerance. The nomenclature for each sheet was designated 1T, 1B, 2T, 2B where the numeral designates it's location in the wrap and 'T' or 'B' is short for 'top' or 'bottom' half of the solenoid. Micrometer measurements were taken at six locations around the perimeter of each sheet. The width,length, and weight of each piece was then measured. Using an assumed pure lead density of 0.40974 lb/in{sup 3}, an average sheet thickness was calculated and compared to the perimeter thickness measurements. In every case, the calculated average thickness was a few mils thinner than the perimeter measurements. The ratio was constant, 0.98. This discrepancy is likely due to the assumed pure lead density. It is not felt that the perimeter is thicker than the center regions. The data suggests that the physical thickness of the sheets is uniform to +/- 0.0015-inch.

  8. Measuring coal thickness

    NASA Technical Reports Server (NTRS)

    Barker, C.; Blaine, J.; Geller, G.; Robinson, R.; Summers, D.; Tyler, J.

    1980-01-01

    Laboratory tested concept, for measuring thickness of overhead coal using noncontacting sensor system coupled to controller and high pressure water jet, allows mining machines to remove virtually all coal from mine roofs without danger of cutting into overlying rock.

  9. Automatic section thickness determination using an absolute gradient focus function.

    PubMed

    Elozory, D T; Kramer, K A; Chaudhuri, B; Bonam, O P; Goldgof, D B; Hall, L O; Mouton, P R

    2012-12-01

    Quantitative analysis of microstructures using computerized stereology systems is an essential tool in many disciplines of bioscience research. Section thickness determination in current nonautomated approaches requires manual location of upper and lower surfaces of tissue sections. In contrast to conventional autofocus functions that locate the optimally focused optical plane using the global maximum on a focus curve, this study identified by two sharp 'knees' on the focus curve as the transition from unfocused to focused optical planes. Analysis of 14 grey-scale focus functions showed, the thresholded absolute gradient function, was best for finding detectable bends that closely correspond to the bounding optical planes at the upper and lower tissue surfaces. Modifications to this function generated four novel functions that outperformed the original. The 'modified absolute gradient count' function outperformed all others with an average error of 0.56 μm on a test set of images similar to the training set; and, an average error of 0.39 μm on a test set comprised of images captured from a different case, that is, different staining methods on a different brain region from a different subject rat. We describe a novel algorithm that allows for automatic section thickness determination based on just out-of-focus planes, a prerequisite for fully automatic computerized stereology.

  10. Measurement of opaque film thickness

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Jaarinen, J.; Reyes, C.; Oppenheim, I. C.; Favro, L. D.; Kuo, P. K.

    1987-01-01

    The theoretical and experimental framework for thickness measurements of thin metal films by low frequency thermal waves is described. Although it is assumed that the films are opaque and the substrates are comparatively poor thermal conductors, the theory is easily extended to other cases of technological interest. A brief description is given of the thermal waves and the experimental arrangement and parameters. The usefulness of the technique is illustrated for making absolute measurements of the thermal diffusivities of isotropic substrate materials. This measurement on pure elemental solids provides a check on the three dimensional theory in the limiting case of zero film thickness. The theoretical framework is then presented, along with numerical calculations and corresponding experimental results for the case of copper films on a glass substrate.

  11. Waterway Ice Thickness Measurements

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The ship on the opposite page is a U. S. Steel Corporation tanker cruising through the ice-covered waters of the Great Lakes in the dead of winter. The ship's crew is able to navigate safely by plotting courses through open water or thin ice, a technique made possible by a multi-agency technology demonstration program in which NASA is a leading participant. Traditionally, the Great Lakes-St. Lawrence Seaway System is closed to shipping for more than three months of winter season because of ice blockage, particularly fluctuations in the thickness and location of ice cover due to storms, wind, currents and variable temperatures. Shippers have long sought a system of navigation that would allow year-round operation on the Lakes and produce enormous economic and fuel conservation benefits. Interrupted operations require that industrial firms stockpile materials to carry them through the impassable months, which is costly. Alternatively, they must haul cargos by more expensive overland transportation. Studies estimate the economic benefits of year-round Great Lakes shipping in the hundreds of millions of dollars annually and fuel consumption savings in the tens of millions of gallons. Under Project Icewarn, NASA, the U.S. Coast Guard and the National Oceanic Atmospheric Administration collaborated in development and demonstration of a system that permits safe year-round operations. It employs airborne radars, satellite communications relay and facsimile transmission to provide shippers and ships' masters up-to-date ice charts. Lewis Research Center contributed an accurate methods of measuring ice thickness by means of a special "short-pulse" type of radar. In a three-year demonstration program, Coast Guard aircraft equipped with Side-Looking Airborne Radar (SLAR) flew over the Great Lakes three or four times a week. The SLAR, which can penetrate clouds, provided large area readings of the type and distribution of ice cover. The information was supplemented by short

  12. Absolute Distance Measurement with the MSTAR Sensor

    NASA Technical Reports Server (NTRS)

    Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

    2003-01-01

    The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

  13. Absolute measurement of length with nanometric resolution

    NASA Astrophysics Data System (ADS)

    Apostol, D.; Garoi, F.; Timcu, A.; Damian, V.; Logofatu, P. C.; Nascov, V.

    2005-08-01

    Laser interferometer displacement measuring transducers have a well-defined traceability route to the definition of the meter. The laser interferometer is de-facto length scale for applications in micro and nano technologies. However their physical unit -half lambda is too large for nanometric resolution. Fringe interpolation-usual technique to improve the resolution-lack of reproducibility could be avoided using the principles of absolute distance measurement. Absolute distance refers to the use of interferometric techniques for determining the position of an object without the necessity of measuring continuous displacements between points. The interference pattern as produced by the interference of two point-like coherent sources is fitted to a geometric model so as to determine the longitudinal location of the target by minimizing least square errors. The longitudinal coordinate of the target was measured with accuracy better than 1 nm, for a target position range of 0.4μm.

  14. An absolute measure for a key currency

    NASA Astrophysics Data System (ADS)

    Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

    It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

  15. Improved Coal-Thickness Measurement

    NASA Technical Reports Server (NTRS)

    Barr, T. A.

    1984-01-01

    Summed signals and dielectric-filled antenna improve measurement. Improved FM radar for measuring thickness of coal seam eliminates spectrum splitting and reduces magnitude of echo from front coal surface.

  16. Measurement of absolute gravity acceleration in Firenze

    NASA Astrophysics Data System (ADS)

    de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

    2011-01-01

    This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

  17. System for absolute measurements by interferometric sensors

    NASA Astrophysics Data System (ADS)

    Norton, Douglas A.

    1993-03-01

    The most common problem of interferometric sensors is their inability to measure absolute path imbalance. Presented in this paper is a signal processing system that gives absolute, unambiguous reading of optical path difference for almost any style of interferometric sensor. Key components are a wide band (incoherent) optical source, a polychromator, and FFT electronics. Advantages include no moving parts in the signal processor, no active components at the sensor location, and the use of standard single mode fiber for sensor illumination and signal transmission. Actual absolute path imbalance of the interferometer is determined without using fringe counting or other inferential techniques. The polychromator extracts the interference information that occurs at each discrete wavelength within the spectral band of the optical source. The signal processing consists of analog and digital filtering, Fast Fourier analysis, and a peak detection and interpolation algorithm. This system was originally designed for use in a remote pressure sensing application that employed a totally passive fiber optic interferometer. A performance qualification was made using a Fabry-Perot interferometer and a commercially available laser interferometer to measure the reference displacement.

  18. Gauge Measures Thicknesses Of Blankets

    NASA Technical Reports Server (NTRS)

    Hagen, George R.; Yoshino, Stanley Y.

    1991-01-01

    Tool makes highly repeatable measurements of thickness of penetrable blanket insulation. Includes commercial holder for replaceable knife blades, which holds needle instead of knife. Needle penetrates blanket to establish reference plane. Ballasted slider applies fixed preload to blanket. Technician reads thickness value on scale.

  19. Measuring Thicknesses of Wastewater Films

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Davenport, R. J.

    1987-01-01

    Sensor determines when thickness of film of electrically conductive wastewater on rotating evaporator drum exceeds preset value. Sensor simple electrical probe that makes contact with liquid surface. Made of materials resistant to chemicals in liquid. Mounted on shaft in rotating cylinder, liquid-thickness sensor extends toward cylinder wall so tip almost touches. Sensor body accommodates probe measuring temperature of evaporated water in cylinder.

  20. Absolute method of measuring magnetic susceptibility

    USGS Publications Warehouse

    Thorpe, A.; Senftle, F.E.

    1959-01-01

    An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

  1. In vivo absorption spectroscopy for absolute measurement.

    PubMed

    Furukawa, Hiromitsu; Fukuda, Takashi

    2012-10-01

    In in vivo spectroscopy, there are differences between individual subjects in parameters such as tissue scattering and sample concentration. We propose a method that can provide the absolute value of a particular substance concentration, independent of these individual differences. Thus, it is not necessary to use the typical statistical calibration curve, which assumes an average level of scattering and an averaged concentration over individual subjects. This method is expected to greatly reduce the difficulties encountered during in vivo measurements. As an example, for in vivo absorption spectroscopy, the method was applied to the reflectance measurement in retinal vessels to monitor their oxygen saturation levels. This method was then validated by applying it to the tissue phantom under a variety of absorbance values and scattering efficiencies.

  2. Measured and modelled absolute gravity in Greenland

    NASA Astrophysics Data System (ADS)

    Nielsen, E.; Forsberg, R.; Strykowski, G.

    2012-12-01

    Present day changes in the ice volume in glaciated areas like Greenland will change the load on the Earth and to this change the lithosphere will respond elastically. The Earth also responds to changes in the ice volume over a millennial time scale. This response is due to the viscous properties of the mantle and is known as Glaical Isostatic Adjustment (GIA). Both signals are present in GPS and absolute gravity (AG) measurements and they will give an uncertainty in mass balance estimates calculated from these data types. It is possible to separate the two signals if both gravity and Global Positioning System (GPS) time series are available. DTU Space acquired an A10 absolute gravimeter in 2008. One purpose of this instrument is to establish AG time series in Greenland and the first measurements were conducted in 2009. Since then are 18 different Greenland GPS Network (GNET) stations visited and six of these are visited more then once. The gravity signal consists of three signals; the elastic signal, the viscous signal and the direct attraction from the ice masses. All of these signals can be modelled using various techniques. The viscous signal is modelled by solving the Sea Level Equation with an appropriate ice history and Earth model. The free code SELEN is used for this. The elastic signal is modelled as a convolution of the elastic Greens function for gravity and a model of present day ice mass changes. The direct attraction is the same as the Newtonian attraction and is calculated as this. Here we will present the preliminary results of the AG measurements in Greenland. We will also present modelled estimates of the direct attraction, the elastic and the viscous signals.

  3. Extracting infrared absolute reflectance from relative reflectance measurements.

    PubMed

    Berets, Susan L; Milosevic, Milan

    2012-06-01

    Absolute reflectance measurements are valuable to the optics industry for development of new materials and optical coatings. Yet, absolute reflectance measurements are notoriously difficult to make. In this paper, we investigate the feasibility of extracting the absolute reflectance from a relative reflectance measurement using a reference material with known refractive index.

  4. Elevation correction factor for absolute pressure measurements

    NASA Technical Reports Server (NTRS)

    Panek, Joseph W.; Sorrells, Mark R.

    1996-01-01

    With the arrival of highly accurate multi-port pressure measurement systems, conditions that previously did not affect overall system accuracy must now be scrutinized closely. Errors caused by elevation differences between pressure sensing elements and model pressure taps can be quantified and corrected. With multi-port pressure measurement systems, the sensing elements are connected to pressure taps that may be many feet away. The measurement system may be at a different elevation than the pressure taps due to laboratory space or test article constraints. This difference produces a pressure gradient that is inversely proportional to height within the interface tube. The pressure at the bottom of the tube will be higher than the pressure at the top due to the weight of the tube's column of air. Tubes with higher pressures will exhibit larger absolute errors due to the higher air density. The above effect is well documented but has generally been taken into account with large elevations only. With error analysis techniques, the loss in accuracy from elevation can be easily quantified. Correction factors can be applied to maintain the high accuracies of new pressure measurement systems.

  5. System for measuring film thickness

    DOEpatents

    Batishko, Charles R.; Kirihara, Leslie J.; Peters, Timothy J.; Rasmussen, Donald E.

    1990-01-01

    A system for determining the thicknesses of thin films of materials exhibiting fluorescence in response to exposure to excitation energy from a suitable source of such energy. A section of film is illuminated with a fixed level of excitation energy from a source such as an argon ion laser emitting blue-green light. The amount of fluorescent light produced by the film over a limited area within the section so illuminated is then measured using a detector such as a photomultiplier tube. Since the amount of fluorescent light produced is a function of the thicknesses of thin films, the thickness of a specific film can be determined by comparing the intensity of fluorescent light produced by this film with the intensity of light produced by similar films of known thicknesses in response to the same amount of excitation energy. The preferred embodiment of the invention uses fiber optic probes in measuring the thicknesses of oil films on the operational components of machinery which are ordinarily obscured from view.

  6. Absolute Seebeck Coefficient Measurements of Thermoelectric Thin Films

    NASA Astrophysics Data System (ADS)

    Mason, Sarah; Avery, Azure; Basset, Dain; Zink, Barry

    2014-03-01

    Significant advancements in thermoelectric device efficiencies are possible through size reduction to the nanoscale. Quantities that determine a material's efficiency, such as thermopower, or Seebeck coefficient, S, are influenced by the measurement apparatus, so that measuring a thermally generated voltage gives, dV/dT =Ssample -Slead . If accurate values of, Slead, are available, simple subtraction provides Ssample. This is rarely the case in measurements using micromachined devices, with leads exclusively made from thin film materials that do not have well known bulk-like thermopower values. We have developed a technique to directly measure S as a function of T using a micromachined thermal isolation platform consisting of a suspended, patterned SiN membrane. By measuring a series of thicknesses of metallic films up to the infinitely thick thin film limit, in which the thermopower is no longer increasing with thickness, but still not at bulk values, we are able to show the contribution of the leads needed to measure this property. Having a thorough understanding of the background contribution we are able to determine the absolute thermopower of a wide variety of thin films, as well as their thermal and electrical conductivities, on the same sample.

  7. Absolute flux measurements for swift atoms

    NASA Technical Reports Server (NTRS)

    Fink, M.; Kohl, D. A.; Keto, J. W.; Antoniewicz, P.

    1987-01-01

    While a torsion balance in vacuum can easily measure the momentum transfer from a gas beam impinging on a surface attached to the balance, this measurement depends on the accommodation coefficients of the atoms with the surface and the distribution of the recoil. A torsion balance is described for making absolute flux measurements independent of recoil effects. The torsion balance is a conventional taut suspension wire design and the Young modulus of the wire determines the relationship between the displacement and the applied torque. A compensating magnetic field is applied to maintain zero displacement and provide critical damping. The unique feature is to couple the impinging gas beam to the torsion balance via a Wood's horn, i.e., a thin wall tube with a gradual 90 deg bend. Just as light is trapped in a Wood's horn by specular reflection from the curved surfaces, the gas beam diffuses through the tube. Instead of trapping the beam, the end of the tube is open so that the atoms exit the tube at 90 deg to their original direction. Therefore, all of the forward momentum of the gas beam is transferred to the torsion balance independent of the angle of reflection from the surfaces inside the tube.

  8. Tube wall thickness measurement apparatus

    DOEpatents

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  9. Tube wall thickness measurement apparatus

    DOEpatents

    Lagasse, Paul R.

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  10. New Techniques for Absolute Gravity Measurements.

    DTIC Science & Technology

    1983-01-07

    Hammond, J.A. (1978) Bollettino Di Geofisica Teorica ed Applicata Vol. XX. 8. Hammond, J. A., and Iliff, R. L. (1979) The AFGL absolute gravity system...International Gravimetric Bureau, No. L:I-43. 7. Hammond. J.A. (1978) Bollettino Di Geofisica Teorica ed Applicata Vol. XX. 8. Hammond, J.A., and

  11. Absolute measurements of fast neutrons using yttrium.

    PubMed

    Roshan, M V; Springham, S V; Rawat, R S; Lee, P; Krishnan, M

    2010-08-01

    Yttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be f(n) approximately 4.1x10(-4) with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 10(8) neutrons per discharge.

  12. Measuring Rind Thickness on Polyurethane Foam

    NASA Technical Reports Server (NTRS)

    Johnson, C.; Miller, J.; Brown, H.

    1985-01-01

    Nondestructive test determines rind thickness of polyurethane foam. Surface harness of foam measured by Shore durometer method: hardness on Shore D scale correlates well with rind thickness. Shore D hardness of 20, for example, indicates rind thickness of 0.04 inch (1 millimeter). New hardness test makes it easy to determine rind thickness of sample nondestructively and to adjust fabrication variables accordingly.

  13. Measuring the absolute magnetic field using high-Tc SQUID

    NASA Astrophysics Data System (ADS)

    He, D. F.; Itozaki, H.

    2006-06-01

    SQUID normally can only measure the change of magnetic field instead of the absolute value of magnetic field. Using a compensation method, a mobile SQUID, which could keep locked when moving in the earth's magnetic field, was developed. Using the mobile SQUID, it was possible to measure the absolute magnetic field. The absolute value of magnetic field could be calculated from the change of the compensation output when changing the direction of the SQUID in a magnetic field. Using this method and the mobile SQUID, we successfully measured the earth's magnetic field in our laboratory.

  14. Absolute quantum yield measurement of powder samples.

    PubMed

    Moreno, Luis A

    2012-05-12

    Measurement of fluorescence quantum yield has become an important tool in the search for new solutions in the development, evaluation, quality control and research of illumination, AV equipment, organic EL material, films, filters and fluorescent probes for bio-industry. Quantum yield is calculated as the ratio of the number of photons absorbed, to the number of photons emitted by a material. The higher the quantum yield, the better the efficiency of the fluorescent material. For the measurements featured in this video, we will use the Hitachi F-7000 fluorescence spectrophotometer equipped with the Quantum Yield measuring accessory and Report Generator program. All the information provided applies to this system. Measurement of quantum yield in powder samples is performed following these steps: 1. Generation of instrument correction factors for the excitation and emission monochromators. This is an important requirement for the correct measurement of quantum yield. It has been performed in advance for the full measurement range of the instrument and will not be shown in this video due to time limitations. 2. Measurement of integrating sphere correction factors. The purpose of this step is to take into consideration reflectivity characteristics of the integrating sphere used for the measurements. 3. Reference and Sample measurement using direct excitation and indirect excitation. 4. Quantum Yield calculation using Direct and Indirect excitation. Direct excitation is when the sample is facing directly the excitation beam, which would be the normal measurement setup. However, because we use an integrating sphere, a portion of the emitted photons resulting from the sample fluorescence are reflected by the integrating sphere and will re-excite the sample, so we need to take into consideration indirect excitation. This is accomplished by measuring the sample placed in the port facing the emission monochromator, calculating indirect quantum yield and correcting the direct

  15. Absolute density measurements in the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Rapp, M.; Gumbel, J.; Lübken, F.-J.

    2001-05-01

    In the last ten years a total of 25 sounding rockets employing ionization gauges have been launched at high latitudes ( ~ 70° N) to measure total atmospheric density and its small scale fluctuations in an altitude range between 70 and 110 km. While the determination of small scale fluctuations is unambiguous, the total density analysis has been complicated in the past by aerodynamical disturbances leading to densities inside the sensor which are enhanced compared to atmospheric values. Here, we present the results of both Monte Carlo simulations and wind tunnel measurements to quantify this aerodynamical effect. The comparison of the resulting ‘ram-factor’ profiles with empirically determined density ratios of ionization gauge measurements and falling sphere measurements provides excellent agreement. This demonstrates both the need, but also the possibility, to correct aerodynamical influences on measurements from sounding rockets. We have determined a total of 20 density profiles of the mesosphere-lower-thermosphere (MLT) region. Grouping these profiles according to season, a listing of mean density profiles is included in the paper. A comparison with density profiles taken from the reference atmospheres CIRA86 and MSIS90 results in differences of up to 40%. This reflects that current reference atmospheres are a significant potential error source for the determination of mixing ratios of, for example, trace gas constituents in the MLT region.

  16. Eddy current thickness measurement apparatus

    DOEpatents

    Rosen, Gary J.; Sinclair, Frank; Soskov, Alexander; Buff, James S.

    2015-06-16

    A sheet of a material is disposed in a melt of the material. The sheet is formed using a cooling plate in one instance. An exciting coil and sensing coil are positioned downstream of the cooling plate. The exciting coil and sensing coil use eddy currents to determine a thickness of the solid sheet on top of the melt.

  17. Absolute Abundance Measurements in Solar Flares

    NASA Astrophysics Data System (ADS)

    Warren, Harry

    2014-06-01

    We present measurements of elemental abundances in solar flares with EVE/SDO and EIS/Hinode. EVE observes both high temperature Fe emission lines Fe XV-XXIV and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (F). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is F=1.17+-0.22. Furthermore, we have compared the EVE measurements with corresponding flare observations of intermediate temperature S, Ar, Ca, and Fe emission lines taken with EIS. Our initial calculations also indicate a photospheric composition for these observations. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation in the non-flaring corona occurs.

  18. Measurements of Absolute Abundances in Solar Flares

    NASA Astrophysics Data System (ADS)

    Warren, Harry P.

    2014-05-01

    We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory. EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (f). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is f = 1.17 ± 0.22. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation occurs.

  19. MEASUREMENTS OF ABSOLUTE ABUNDANCES IN SOLAR FLARES

    SciTech Connect

    Warren, Harry P.

    2014-05-01

    We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory. EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (f). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is f = 1.17 ± 0.22. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation occurs.

  20. Absolute measurement of the photodisintegration of deuterium

    SciTech Connect

    Knott, J.E.

    1988-01-01

    This experiment measured the differential cross section for deuteron photodisintegration between photon energies of 63 and 71 MeV. The photon beam was produced by the bremsstrahlung of an 88.4 MeV CW electron beam, from the University of Illinois Nuclear Physics Laboratory electron microtron, in a 1.4 {times} 10{sup {minus}3} radiation length aluminum converter. The photon energy was determined to .25 MeV by the technique of bremsstrahlung tagging. The deuterium target gas, at atmospheric pressure, was contained in a thin walled cylinder 2.4 m long. The protons from deuteron photo-disintegration were detected in the LArge Solid Angle detector, which was built for this experiment. The LASA detector consists of three concentric, cylindrical MWPC chambers surrounded by segmented plastic scintillators. The target cylinder is on the axis of the chamber. Particles were collected from 20{degrees} to 160{degrees}, the angle determined by the charge division technique in the wire chamber. The de/dx measurements in the wire chamber and the scintillators allowed the separation of protons from electrons. The differential cross sections have been fit by Legendre polynomials. These results are in reasonable agreement with previous experiments and theoretical calculations.

  1. Calibration of Fourier domain short coherence interferometer for absolute distance measurements.

    PubMed

    Montonen, R; Kassamakov, I; Hæggström, E; Österberg, K

    2015-05-20

    We calibrated and determined the measurement uncertainty of a custom-made Fourier domain short coherence interferometer operated in laboratory conditions. We compared the optical thickness of two thickness standards and three coverslips determined with our interferometer to the geometric thickness determined by SEM. Using this calibration data, we derived a calibration function with a 95% confidence level system uncertainty of (5.9×10(-3)r+2.3)  μm, where r is the optical distance in μm, across the 240 μm optical measurement range. The confidence limit includes contributions from uncertainties in the optical thickness, geometric thickness, and refractive index measurements as well as uncertainties arising from cosine errors and thermal expansion. The results show feasibility for noncontacting absolute distance characterization with micrometer-level accuracy. This instrument is intended for verifying the alignment of the discs of an accelerating structure in the possible future compact linear collider.

  2. Absolute photon-flux measurements in the vacuum ultraviolet

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Haddad, G. N.

    1974-01-01

    Absolute photon-flux measurements in the vacuum ultraviolet have extended to short wavelengths by use of rare-gas ionization chambers. The technique involves the measurement of the ion current as a function of the gas pressure in the ion chamber. The true value of the ion current, and hence the absolute photon flux, is obtained by extrapolating the ion current to zero gas pressure. Examples are given at 162 and 266 A. The short-wavelength limit is determined only by the sensitivity of the current-measuring apparatus and by present knowledge of the photoionization processes that occur in the rate gases.

  3. Mathematical Model for Absolute Magnetic Measuring Systems in Industrial Applications

    NASA Astrophysics Data System (ADS)

    Fügenschuh, Armin; Fügenschuh, Marzena; Ludszuweit, Marina; Mojsic, Aleksandar; Sokół, Joanna

    2015-09-01

    Scales for measuring systems are either based on incremental or absolute measuring methods. Incremental scales need to initialize a measurement cycle at a reference point. From there, the position is computed by counting increments of a periodic graduation. Absolute methods do not need reference points, since the position can be read directly from the scale. The positions on the complete scales are encoded using two incremental tracks with different graduation. We present a new method for absolute measuring using only one track for position encoding up to micrometre range. Instead of the common perpendicular magnetic areas, we use a pattern of trapezoidal magnetic areas, to store more complex information. For positioning, we use the magnetic field where every position is characterized by a set of values measured by a hall sensor array. We implement a method for reconstruction of absolute positions from the set of unique measured values. We compare two patterns with respect to uniqueness, accuracy, stability and robustness of positioning. We discuss how stability and robustness are influenced by different errors during the measurement in real applications and how those errors can be compensated.

  4. Measurements of the reactor neutron power in absolute units

    SciTech Connect

    Lebedev, G. V.

    2015-12-15

    The neutron power of the reactor of the Yenisei space nuclear power plant is measured in absolute units using the modernized method of correlation analysis during the ground-based tests of the Yenisei prototypes. Results of the experiments are given. The desired result is obtained in a series of experiments carried out at the stage of the plant preparation for tests. The acceptability of experimental data is confirmed by the results of measuring the reactor neutron power in absolute units at the nominal level by the thermal balance during the life cycle tests of the ground prototypes.

  5. Absolute gain measurement by the image method under mismatched condition

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Baddour, Maurice F.

    1987-01-01

    Purcell's image method for measuring the absolute gain of an antenna is particularly attractive for small test antennas. The method is simple to use and utilizes only one antenna with a reflecting plane to provide an image for the receiving antenna. However, the method provides accurate results only if the antenna is matched to its waveguide. In this paper, a waveguide junction analysis is developed to determine the gain of an antenna under mismatched condition. Absolute gain measurements for two standard gain horn antennas have been carried out. Experimental results agree closely with published data.

  6. Urey: to measure the absolute age of Mars

    NASA Technical Reports Server (NTRS)

    Randolph, J. E.; Plescia, J.; Bar-Cohen, Y.; Bartlett, P.; Bickler, D.; Carlson, R.; Carr, G.; Fong, M.; Gronroos, H.; Guske, P. J.; Herring, M.; Javadi, H.; Johnson, D. W.; Larson, T.; Malaviarachchi, K.; Sherrit, S.; Stride, S.; Trebi-Ollennu, A.; Warwick, R.

    2003-01-01

    UREY, a proposed NASA Mars Scout mission will, for the first time, measure the absolute age of an identified igneous rock formation on Mars. By extension to relatively older and younger rock formations dated by remote sensing, these results will enable a new and better understanding of Martian geologic history.

  7. Absolute concentration measurements inside a jet plume using video digitization

    NASA Astrophysics Data System (ADS)

    Vauquelin, O.

    An experimental system based on digitized video image analysis is used to measure the local value of the concentration inside a plume. Experiments are carried out in a wind-tunnel for a smoke-seeded turbulent jet plume illuminated with a laser beam. Each test is filmed, subsequently video images are digitized and analysed in order to determine the smoke absolute concentration corresponding to each pixel gray level. This non-intrusive measurement technique is first calibrated and different laws connecting gray level to concentration are established. As a first application, concentration measurements are made inside a turbulent jet plume and compared with measurements conducted using a classic gas analysis method. We finally present and discuss the possibilities offered for the measurements of absolute concentration fluctuations.

  8. Lens transmission measurement for an absolute radiation thermometer

    SciTech Connect

    Hao, X.; Yuan, Z.; Lu, X.

    2013-09-11

    The lens transmission for the National Institute of Metrology of China absolute radiation thermometer is measured by a hybrid method. The results of the lens transmission measurements are 99.002% and 86.792% for filter radiometers with center wavelengths 633 nm and 900 nm, respectively. These results, after correcting for diffraction factors and the size-of-source effect when the lens is incorporated within the radiometer, can be used for measurement of thermodynamic temperature. The expanded uncertainty of the lens transmission measurement system has been evaluated. It is 1.3×10{sup −3} at 633 nm and 900 nm, respectively.

  9. Absolute gravity acceleration measurement in atomic sensor laboratories

    NASA Astrophysics Data System (ADS)

    de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

    2012-03-01

    This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the Florence University (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the measurement of forces with high spatial resolution are in progress. Both experiments require an independent knowledge on the local value of g. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are ( 980 492 160.6 ± 4.0) μGal and ( 980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

  10. Absolute length measurement using manually decided stereo correspondence for endoscopy

    NASA Astrophysics Data System (ADS)

    Sasaki, M.; Koishi, T.; Nakaguchi, T.; Tsumura, N.; Miyake, Y.

    2009-02-01

    In recent years, various kinds of endoscope have been developed and widely used to endoscopic biopsy, endoscopic operation and endoscopy. The size of the inflammatory part is important to determine a method of medical treatment. However, it is not easy to measure absolute size of inflammatory part such as ulcer, cancer and polyp from the endoscopic image. Therefore, it is required measuring the size of those part in endoscopy. In this paper, we propose a new method to measure the absolute length in a straight line between arbitrary two points based on the photogrammetry using endoscope with magnetic tracking sensor which gives camera position and angle. In this method, the stereo-corresponding points between two endoscopic images are determined by the endoscopist without any apparatus of projection and calculation to find the stereo correspondences, then the absolute length can be calculated on the basis of the photogrammetry. The evaluation experiment using a checkerboard showed that the errors of the measurements are less than 2% of the target length when the baseline is sufficiently-long.

  11. Non-contact thickness measurement using UTG

    NASA Technical Reports Server (NTRS)

    Bui, Hoa T. (Inventor)

    1996-01-01

    A measurement structure for determining the thickness of a specimen without mechanical contact but instead employing ultrasonic waves including an ultrasonic transducer and an ultrasonic delay line connected to the transducer by a retainer or collar. The specimen, whose thickness is to be measured, is positioned below the delay line. On the upper surface of the specimen a medium such as a drop of water is disposed which functions to couple the ultrasonic waves from the delay line to the specimen. A receiver device, which may be an ultrasonic thickness gauge, receives reflected ultrasonic waves reflected from the upper and lower surface of the specimen and determines the thickness of the specimen based on the time spacing of the reflected waves.

  12. Absolute measurement of the extreme UV solar flux

    NASA Technical Reports Server (NTRS)

    Carlson, R. W.; Ogawa, H. S.; Judge, D. L.; Phillips, E.

    1984-01-01

    A windowless rare-gas ionization chamber has been developed to measure the absolute value of the solar extreme UV flux in the 50-575-A region. Successful results were obtained on a solar-pointing sounding rocket. The ionization chamber, operated in total absorption, is an inherently stable absolute detector of ionizing UV radiation and was designed to be independent of effects from secondary ionization and gas effusion. The net error of the measurement is + or - 7.3 percent, which is primarily due to residual outgassing in the instrument, other errors such as multiple ionization, photoelectron collection, and extrapolation to the zero atmospheric optical depth being small in comparison. For the day of the flight, Aug. 10, 1982, the solar irradiance (50-575 A), normalized to unit solar distance, was found to be 5.71 + or - 0.42 x 10 to the 10th photons per sq cm sec.

  13. Glue Film Thickness Measurements by Spectral Reflectance

    SciTech Connect

    B. R. Marshall

    2010-09-20

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 μm, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  14. Measurement of the absolute solar UV irradiance and variability

    NASA Technical Reports Server (NTRS)

    Mentall, James E.

    1990-01-01

    Radiation in the wavelength interval 150-350 nm initiates chemical reactions in the lower mesosphere and the stratosphere through the photodissociation of ambient molecular species. This experiment measures the total solar irradiance, above the Earth's atmosphere, in this wavelength interval, using three spectrometers. Measurements are made from rockets on a once-a-year basis and are used with satellite observations to determine both the absolute irradiance and the long term variability of the sun in the UV. A fourth spectrometer is being added to the payload to measure the emission in the hydrogen Lyman-alpha emission at 121.67 nm.

  15. Precision Absolute Beam Current Measurement of Low Power Electron Beam

    SciTech Connect

    Ali, M. M.; Bevins, M. E.; Degtiarenko, P.; Freyberger, A.; Krafft, G. A.

    2012-11-01

    Precise measurements of low power CW electron beam current for the Jefferson Lab Nuclear Physics program have been performed using a Tungsten calorimeter. This paper describes the rationale for the choice of the calorimeter technique, as well as the design and calibration of the device. The calorimeter is in use presently to provide a 1% absolute current measurement of CW electron beam with 50 to 500 nA of average beam current and 1-3 GeV beam energy. Results from these recent measurements will also be presented.

  16. Reliability of Various Measurement Stations for Determining Plantar Fascia Thickness and Echogenicity.

    PubMed

    Bisi-Balogun, Adebisi; Cassel, Michael; Mayer, Frank

    2016-04-13

    This study aimed to determine the relative and absolute reliability of ultrasound (US) measurements of the thickness and echogenicity of the plantar fascia (PF) at different measurement stations along its length using a standardized protocol. Twelve healthy subjects (24 feet) were enrolled. The PF was imaged in the longitudinal plane. Subjects were assessed twice to evaluate the intra-rater reliability. A quantitative evaluation of the thickness and echogenicity of the plantar fascia was performed using Image J, a digital image analysis and viewer software. A sonography evaluation of the thickness and echogenicity of the PF showed a high relative reliability with an Intra class correlation coefficient of ≥0.88 at all measurement stations. However, the measurement stations for both the PF thickness and echogenicity which showed the highest intraclass correlation coefficient (ICCs) did not have the highest absolute reliability. Compared to other measurement stations, measuring the PF thickness at 3 cm distal and the echogenicity at a region of interest 1 cm to 2 cm distal from its insertion at the medial calcaneal tubercle showed the highest absolute reliability with the least systematic bias and random error. Also, the reliability was higher using a mean of three measurements compared to one measurement. To reduce discrepancies in the interpretation of the thickness and echogenicity measurements of the PF, the absolute reliability of the different measurement stations should be considered in clinical practice and research rather than the relative reliability with the ICC.

  17. Reliability of Various Measurement Stations for Determining Plantar Fascia Thickness and Echogenicity

    PubMed Central

    Bisi-Balogun, Adebisi; Cassel, Michael; Mayer, Frank

    2016-01-01

    This study aimed to determine the relative and absolute reliability of ultrasound (US) measurements of the thickness and echogenicity of the plantar fascia (PF) at different measurement stations along its length using a standardized protocol. Twelve healthy subjects (24 feet) were enrolled. The PF was imaged in the longitudinal plane. Subjects were assessed twice to evaluate the intra-rater reliability. A quantitative evaluation of the thickness and echogenicity of the plantar fascia was performed using Image J, a digital image analysis and viewer software. A sonography evaluation of the thickness and echogenicity of the PF showed a high relative reliability with an Intra class correlation coefficient of ≥0.88 at all measurement stations. However, the measurement stations for both the PF thickness and echogenicity which showed the highest intraclass correlation coefficient (ICCs) did not have the highest absolute reliability. Compared to other measurement stations, measuring the PF thickness at 3 cm distal and the echogenicity at a region of interest 1 cm to 2 cm distal from its insertion at the medial calcaneal tubercle showed the highest absolute reliability with the least systematic bias and random error. Also, the reliability was higher using a mean of three measurements compared to one measurement. To reduce discrepancies in the interpretation of the thickness and echogenicity measurements of the PF, the absolute reliability of the different measurement stations should be considered in clinical practice and research rather than the relative reliability with the ICC. PMID:27089369

  18. Oblique-incidence sounder measurements with absolute propagation delay timing

    SciTech Connect

    Daehler, M.

    1990-05-03

    Timing from the Global Position Satellite (GPS) system has been applied to HF oblique incidence sounder measurements to produce ionograms whose propagation delay time scale is absolutely calibrated. Such a calibration is useful for interpreting ionograms in terms of the electron density true-height profile for the ionosphere responsible for the propagation. Use of the time variations in the shape of the electron density profile, in conjunction with an HF propagation model, is expected to provide better near-term (1-24 hour) HF propagation forecasts than are available from current updating systems, which use only the MUF. Such a capability may provide the basis for HF frequency management techniques which are more efficient than current methods. Absolute timing and other techniques applicable to automatic extraction of the electron-density profile from an ionogram will be discussed.

  19. Wall thickness measuring method and apparatus

    DOEpatents

    Salzer, Leander J.; Bergren, Donald A.

    1989-01-01

    An apparatus for measuring the wall thickness of a nonmagnetic article having a housing supporting a magnet and a contiguous supporting surface. The tubular article and the housing are releasably secured to the supporting surface and a support member of an optical comparator, respectively. To determine the wall thickness of the article at a selected point, a magnetically responsive ball is positioned within the tubular article over said point and retained therein by means of a magnetic field produced by the magnet. Thereafter, an optical comparator is employed to project a magnified image of the ball on a screen and the wall thickness at the selected point is calculated by using a ball surface measurement taken with the comparator in conjunction with a previously determined base line measurement.

  20. Strategy for the absolute neutron emission measurement on ITER.

    PubMed

    Sasao, M; Bertalot, L; Ishikawa, M; Popovichev, S

    2010-10-01

    Accuracy of 10% is demanded to the absolute fusion measurement on ITER. To achieve this accuracy, a functional combination of several types of neutron measurement subsystem, cross calibration among them, and in situ calibration are needed. Neutron transport calculation shows the suitable calibration source is a DT/DD neutron generator of source strength higher than 10(10) n/s (neutron/second) for DT and 10(8) n/s for DD. It will take eight weeks at the minimum with this source to calibrate flux monitors, profile monitors, and the activation system.

  1. Game theory and evolution: finite size and absolute fitness measures.

    PubMed

    Demetrius, L; Gundlach, V M

    2000-11-01

    This article is concerned with the characterization and existence of evolutionarily stable strategies (ESS) in Games against Nature, a class of models described by finite size populations and absolute fitness measures. We address these problems in terms of a new formalism which revolves around the concept evolutionary entropy, a measure of the diversity of options associated with a strategy pure - strategies have zero entropy, mixed strategies positive entropy. We invoke this formalism to show that ESS are characterized by extremal states of entropy. We illustrate this characterization of ESS by an analysis of the evolution of the sex ratio and the evolution of seed size.

  2. Myocardium wall thickness transducer and measuring method

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Silver, R. H.; Culler, V. H. (Inventor)

    1976-01-01

    A miniature transducer for measuring changes of thickness of the myocardium is described. The device is easily implantable without traumatizing the subject, without affecting the normal muscle behavior, and is removable and implantable at a different muscle location. Operating features of the device are described.

  3. In vitro enamel thickness measurements with ultrasound.

    PubMed

    Sindi, Khalid Hussain; Bubb, Nigel Lawrence; Gutteridge, Diana Lynn; Evans, Joseph Anthony

    2015-01-01

    In the work described here, agreement between ultrasound and histologic measurements of enamel thickness in vitro was investigated. Fifteen extracted human premolars were sectioned coronally to produce 30 sections. The enamel thickness of each specimen was measured with a 15-MHz hand-held ultrasound probe and verified with histology. The speed of sound in enamel was established. Bland-Altman analysis, intra-class correlation coefficient and Wilcoxon sign rank test were used to assess agreement. The mean speed of sound in enamel was 6191 ± 199 m s(-1). Bland-Altman limits of agreement were -0.16 to 0.18 mm when the speed of sound for each specimen was used, and -0.17 to 0.21 mm when the mean speed of sound was used. Intra-class correlation coefficient agreement was 0.97, and the Wilcoxon sign rank test yielded a p-value of 0.55. Using the speed of sound for each specimen results in more accurate measurement of enamel thickness. Ultrasound measurements were in good agreement with histology, which highlights its potential for monitoring the progressive loss of enamel thickness in erosive tooth surface loss.

  4. Nanofilm thickness measurement by resonant frequencies

    SciTech Connect

    Latyshev, A V; Yushkanov, A A

    2015-03-31

    We report a theoretical investigation of monochromatic laser light – thin metal film interaction. The dependences of transmission, reflection and absorption coefficients of an electromagnetic wave on the incidence angle, layer thickness and effective electron collision frequency are obtained. The above coefficients are analysed in the region of resonant frequencies. The resulting formula for the transmission, reflection and absorption coefficients are found to be valid for any angles of incidence. The case of mirror boundary conditions is considered. A formula is derived for contactless measurement of the film thickness by the observed resonant frequencies. (laser applications and other topics in quantum electronics)

  5. Absolute Radiation Measurements in Earth and Mars Entry Conditions

    NASA Technical Reports Server (NTRS)

    Cruden, Brett A.

    2014-01-01

    This paper reports on the measurement of radiative heating for shock heated flows which simulate conditions for Mars and Earth entries. Radiation measurements are made in NASA Ames' Electric Arc Shock Tube at velocities from 3-15 km/s in mixtures of N2/O2 and CO2/N2/Ar. The technique and limitations of the measurement are summarized in some detail. The absolute measurements will be discussed in regards to spectral features, radiative magnitude and spatiotemporal trends. Via analysis of spectra it is possible to extract properties such as electron density, and rotational, vibrational and electronic temperatures. Relaxation behind the shock is analyzed to determine how these properties relax to equilibrium and are used to validate and refine kinetic models. It is found that, for some conditions, some of these values diverge from non-equilibrium indicating a lack of similarity between the shock tube and free flight conditions. Possible reasons for this are discussed.

  6. An absolute scale for measuring the utility of money

    NASA Astrophysics Data System (ADS)

    Thomas, P. J.

    2010-07-01

    Measurement of the utility of money is essential in the insurance industry, for prioritising public spending schemes and for the evaluation of decisions on protection systems in high-hazard industries. Up to this time, however, there has been no universally agreed measure for the utility of money, with many utility functions being in common use. In this paper, we shall derive a single family of utility functions, which have risk-aversion as the only free parameter. The fact that they return a utility of zero at their low, reference datum, either the utility of no money or of one unit of money, irrespective of the value of risk-aversion used, qualifies them to be regarded as absolute scales for the utility of money. Evidence of validation for the concept will be offered based on inferential measurements of risk-aversion, using diverse measurement data.

  7. Absolute efficiency measurements with the 10B based Jalousie detector

    NASA Astrophysics Data System (ADS)

    Modzel, G.; Henske, M.; Houben, A.; Klein, M.; Köhli, M.; Lennert, P.; Meven, M.; Schmidt, C. J.; Schmidt, U.; Schweika, W.

    2014-04-01

    The 10B based Jalousie detector is a replacement for 3He counter tubes, which are nowadays less affordable for large area detectors due to the 3He crisis. In this paper we investigate and verify the performance of the new 10B based detector concept and its adoption for the POWTEX diffractometer, which is designed for the detection of thermal neutrons with predicted detection efficiencies of 75-50% for neutron energies of 10-100 meV, respectively. The predicted detection efficiency has been verified by absolute measurements using neutrons with a wavelength of 1.17 Å (59 meV).

  8. Absolute distance measurement based on multiple self-mixing interferometry

    NASA Astrophysics Data System (ADS)

    Duan, Zhiwei; Yu, Yangyang; Gao, Bingkun; Jiang, Chunlei

    2017-04-01

    To improve the precision of distance measurement using laser Self-Mixing Interferometry (SMI) and compute short distance, we propose a method of Multiple Self-Mixing Interferometry (MSMI) that is modulated with a triangular wave. The principle of this method has been described in this paper. Experiments at different distances and amplitudes of modulation current are based on the proposed method. Low-priced and easily operated experimental devices are built. Experimental results show that a resolution of 2.7 mm can be achieved for absolute distance ranging from 2.2 to 23 cm.

  9. Absolute measurement of hadronic branching fractions of the Ds+ meson.

    PubMed

    Alexander, J P; Berkelman, K; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Libby, J; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; Lopez, A; Mendez, H; Ramirez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Rademacker, J; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L

    2008-04-25

    The branching fractions of D(s)(+/-) meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 pb(-1) of e(+)e(-) collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D(s)(+/-) decays with a double tag technique. In particular we determine the branching fraction B(D(s)(+)-->K(-)K(+}pi(+))=(5.50+/-0.23+/-0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K(-)K(+)pi(+) decay mode.

  10. 3D measurement of absolute radiation dose in grid therapy

    NASA Astrophysics Data System (ADS)

    Trapp, J. V.; Warrington, A. P.; Partridge, M.; Philps, A.; Leach, M. O.; Webb, S.

    2004-01-01

    Spatially fractionated radiotherapy through a grid is a concept which has a long history and was routinely used in orthovoltage radiation therapy in the middle of last century to minimize damage to the skin and subcutaneous tissue. With the advent of megavoltage radiotherapy and its skin sparing effects the use of grids in radiotherapy declined in the 1970s. However there has recently been a revival of the technique for use in palliative treatments with a single fraction of 10 to 20 Gy. In this work the absolute 3D dose distribution in a grid irradiation is measured for photons using a combination of film and gel dosimetry.

  11. Dispersive white-light spectral interferometry with absolute phase retrieval to measure thin film.

    PubMed

    Hlubina, P; Ciprian, D; Lunácek, J; Lesnák, M

    2006-08-21

    We present a white-light spectral interferometric technique for measuring the absolute spectral optical path difference (OPD) between the beams in a slightly dispersive Michelson interferometer with a thin-film structure as a mirror. We record two spectral interferograms to obtain the spectral interference signal and retrieve from it the spectral phase, which includes the effect of a cube beam splitter and the phase change on reflection from the thin-film structure. Knowing the effective thickness and dispersion of the beam splitter made of BK7 optical glass, we use a simple procedure to determine both the absolute spectral phase difference and OPD. The spectral OPD is measured for a uniform SiO(2) thin film on a silicon wafer and is fitted to the theoretical spectral OPD to obtain the thin-film thickness. The theoretical spectral OPD is determined provided that the optical constants of the thin-film structure are known. We measure also the nonlinear-like spectral phase and fit it to the theoretical values in order to obtain the thin-film thickness.

  12. Full field imaging based instantaneous hyperspectral absolute refractive index measurement

    SciTech Connect

    Baba, Justin S; Boudreaux, Philip R

    2012-01-01

    Multispectral refractometers typically measure refractive index (RI) at discrete monochromatic wavelengths via a serial process. We report on the demonstration of a white light full field imaging based refractometer capable of instantaneous multispectral measurement of absolute RI of clear liquid/gel samples across the entire visible light spectrum. The broad optical bandwidth refractometer is capable of hyperspectral measurement of RI in the range 1.30 1.70 between 400nm 700nm with a maximum error of 0.0036 units (0.24% of actual) at 414nm for a = 1.50 sample. We present system design and calibration method details as well as results from a system validation sample.

  13. Absolute stress measurements at the rangely anticline, Northwestern Colorado

    USGS Publications Warehouse

    de la Cruz, R. V.; Raleigh, C.B.

    1972-01-01

    Five different methods of measuring absolute state of stress in rocks in situ were used at sites near Rangely, Colorado, and the results compared. For near-surface measurements, overcoring of the borehole-deformation gage is the most convenient and rapid means of obtaining reliable values for the magnitude and direction of the state of stress in rocks in situ. The magnitudes and directions of the principal stresses are compared to the geologic features of the different areas of measurement. The in situ stresses are consistent in orientation with the stress direction inferred from the earthquake focal-plane solutions and existing joint patterns but inconsistent with stress directions likely to have produced the Rangely anticline. ?? 1972.

  14. Absolute rotation detection by Coriolis force measurement using optomechanics

    NASA Astrophysics Data System (ADS)

    Davuluri, Sankar; Li, Yong

    2016-10-01

    In this article, we present an application of the optomechanical cavities for absolute rotation detection. Two optomechanical cavities, one in each arm, are placed in a Michelson interferometer. The interferometer is placed on a rotating table and is moved with a uniform velocity of \\dot{\\bar{y}} with respect to the rotating table. The Coriolis force acting on the interferometer changes the length of the optomechanical cavity in one arm, while the length of the optomechanical cavity in the other arm is not changed. The phase shift corresponding to the change in the optomechanical cavity length is measured at the interferometer output to estimate the angular velocity of the absolute rotation. An analytic expression for the minimum detectable rotation rate corresponding to the standard quantum limit of measurable Coriolis force in the interferometer is derived. Squeezing technique is discussed to improve the rotation detection sensitivity by a factor of \\sqrt{{γ }m/{ω }m} at 0 K temperature, where {γ }m and {ω }m are the damping rate and angular frequency of the mechanical oscillator. The temperature dependence of the rotation detection sensitivity is studied.

  15. Deconstructing European Poverty Measures: What Relative and Absolute Scales Measure

    ERIC Educational Resources Information Center

    Burkhauser, Richard V.

    2009-01-01

    Forster and d'Ercole (2009) outline the dominant method of conceptualization and operationalization of European poverty measures that informed the EU in its development of the questionnaire for the European Union--Survey of Income and Living Conditions (EU-SILC). They do so in the context of their explanation of how the Organization for Economic…

  16. Superfast 3D absolute shape measurement using five binary patterns

    NASA Astrophysics Data System (ADS)

    Hyun, Jae-Sang; Zhang, Song

    2017-03-01

    This paper presents a method that recovers high-quality 3D absolute coordinates point by point with only five binary patterns. Specifically, three dense binary dithered patterns are used to compute the wrapped phase; and the average intensity is combined with two additional binary patterns to determine fringe order pixel by pixel in phase domain. The wrapped phase is temporarily unwrapped point by point by referring to the fringe order. We further developed a computational framework to reduce random noise impact due to dithering, defocusing and random noise. Since only five binary fringe patterns are required to recover one 3D frame, extremely high speed 3D shape measurement can be achieved. For example, we developed a system that captures 2D images at 3333 Hz, and thus performs 3D shape measurement at 667 Hz.

  17. Hot Wall Thickness Variation Measurement System

    DTIC Science & Technology

    1979-06-01

    Subtltia) HOT WALL THICKNESS VARIATION MEASUREMENT SYSTEM 7. AUTHORfa; 3. J. KRUPSKI 9 . PERFORMING ORGANIZATION NAME AND ADDRESS PRODUCT...THE FORGING 3. ULTRASONICS ON A HOT TUBE 4. SYSTEt-l DESCRIPTION 5. TESTING RESULTS 6. CONCLUSIONS 7. HffLEMENTATION PAGE i ii 1 2 4 6 9 ...printed out. The grip procedure was repeated toward the breech end of the forging with good results. The third and 9 breech end prints were at about

  18. Reproducibility of airway wall thickness measurements

    NASA Astrophysics Data System (ADS)

    Schmidt, Michael; Kuhnigk, Jan-Martin; Krass, Stefan; Owsijewitsch, Michael; de Hoop, Bartjan; Peitgen, Heinz-Otto

    2010-03-01

    Airway remodeling and accompanying changes in wall thickness are known to be a major symptom of chronic obstructive pulmonary disease (COPD), associated with reduced lung function in diseased individuals. Further investigation of this disease as well as monitoring of disease progression and treatment effect demand for accurate and reproducible assessment of airway wall thickness in CT datasets. With wall thicknesses in the sub-millimeter range, this task remains challenging even with today's high resolution CT datasets. To provide accurate measurements, taking partial volume effects into account is mandatory. The Full-Width-at-Half-Maximum (FWHM) method has been shown to be inappropriate for small airways1,2 and several improved algorithms for objective quantification of airway wall thickness have been proposed.1-8 In this paper, we describe an algorithm based on a closed form solution proposed by Weinheimer et al.7 We locally estimate the lung density parameter required for the closed form solution to account for possible variations of parenchyma density between different lung regions, inspiration states and contrast agent concentrations. The general accuracy of the algorithm is evaluated using basic tubular software and hardware phantoms. Furthermore, we present results on the reproducibility of the algorithm with respect to clinical CT scans, varying reconstruction kernels, and repeated acquisitions, which is crucial for longitudinal observations.

  19. Absolute poverty measures for the developing world, 1981-2004.

    PubMed

    Chen, Shaohua; Ravallion, Martin

    2007-10-23

    We report new estimates of measures of absolute poverty for the developing world for the period 1981-2004. A clear trend decline in the percentage of people who are absolutely poor is evident, although with uneven progress across regions. We find more mixed success in reducing the total number of poor. Indeed, the developing world outside China has seen little or no sustained progress in reducing the number of poor, with rising poverty counts in some regions, notably sub-Saharan Africa. There are encouraging signs of progress in all regions after 2000, although it is too early to say whether this is a new trend. We also summarize results from estimating a new series incorporating an allowance for the higher cost of living facing poor people in urban areas. This reveals a marked urbanization of poverty in the developing world, which is stronger in some regions than others, although it remains that three-quarters of the poor live in rural areas.

  20. Experimental feasibility of the airborne measurement of absolute oil fluorescence spectral conversion efficiency

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1983-01-01

    Airborne lidar oil spill experiments carried out to determine the practicability of the AOFSCE (absolute oil fluorescence spectral conversion efficiency) computational model are described. The results reveal that the model is suitable over a considerable range of oil film thicknesses provided the fluorescence efficiency of the oil does not approach the minimum detection sensitivity limitations of the lidar system. Separate airborne lidar experiments to demonstrate measurement of the water column Raman conversion efficiency are also conducted to ascertain the ultimate feasibility of converting such relative oil fluorescence to absolute values. Whereas the AOFSCE model is seen as highly promising, further airborne water column Raman conversion efficiency experiments with improved temporal or depth-resolved waveform calibration and software deconvolution techniques are thought necessary for a final determination of suitability.

  1. On measuring the absolute scale of baryon acoustic oscillations

    NASA Astrophysics Data System (ADS)

    Sutherland, Will

    2012-10-01

    The baryon acoustic oscillation (BAO) feature in the distribution of galaxies provides a fundamental standard ruler which is widely used to constrain cosmological parameters. In most analyses, the comoving length of the ruler is inferred from a combination of cosmic microwave background (CMB) observations and theory. However, this inferred length may be biased by various non-standard effects in early universe physics; this can lead to biased inferences of cosmological parameters such as H0, Ωm and w, so it would be valuable to measure the absolute BAO length by combining a galaxy redshift survey and a suitable direct low-z distance measurement. One obstacle is that low-redshift BAO surveys mainly constrain the ratio rS/DV(z), where DV is a dilation scale which is not directly observable by standard candles. Here, we find a new approximation DV(z)≃34DL(43z)(1+43z)-1(1-0.02455 z3+0.0105 z4) which connects DV to the standard luminosity distance DL at a somewhat higher redshift; this is shown to be very accurate (relative error <0.2 per cent) for all Wilkinson Microwave Anisotropy Probe compatible Friedmann models at z < 0.4, with very weak dependence on cosmological parameters H0, Ωm, Ωk, w. This provides a route to measure the absolute BAO length using only observations at z ≲ 0.3, including Type Ia supernovae, and potentially future H0-free physical distance indicators such as gravitational lenses or gravitational wave standard sirens. This would provide a zero-parameter check of the standard cosmology at 103 ≲ z ≲ 105, and can constrain the number of relativistic species Neff with fewer degeneracies than the CMB.

  2. Lunar eclipse photometry: absolute luminance measurements and modeling.

    PubMed

    Hernitschek, Nina; Schmidt, Elmar; Vollmer, Michael

    2008-12-01

    The Moon's time-dependent luminance was determined during the 9 February 1990 and 3 March 2007 total lunar eclipses by using calibrated, industry standard photometers. After the results were corrected to unit air mass and to standard distances for both Moon and Sun, an absolute calibration was accomplished by using the Sun's known luminance and a pre-eclipse lunar albedo of approximately 13.5%. The measured minimum level of brightness in the total phase of both eclipses was relatively high, namely -3.32 m(vis) and -1.7 m(vis), which hints at the absence of pronounced stratospheric aerosol. The light curves were modeled in such a way as to let the Moon move through an artificial Earth shadow composed of a multitude of disk and ring zones, containing a relative luminance data set from an atmospheric radiative transfer calculation.

  3. Method and apparatus for making absolute range measurements

    DOEpatents

    Earl, Dennis D [Knoxville, TN; Allison, Stephen W [Knoxville, TN; Cates, Michael R [Oak Ridge, TN; Sanders, Alvin J [Knoxville, TN

    2002-09-24

    This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through a screen at least partially opaque at the wavelength. The screen has an aperture sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector spaced some distance from the screen. The detector detects the central intensity of the beam as well as a set of intensities displaced from a center of the aperture. The distance from the source to the target can then be calculated based upon the known wavelength, aperture radius, and beam intensity.

  4. Measurement of absolute hadronic branching fractions of D mesons

    NASA Astrophysics Data System (ADS)

    Shi, Xin

    Using 818 pb-1 of e +e- collisions recorded at the psi(3770) resonance with the CLEO-c detector at CESR, we determine absolute hadronic branching fractions of charged and neutral D mesons using a double tag technique. Among measurements for three D 0 and six D+ modes, we obtain reference branching fractions B (D0 → K -pi+) = (3.906 +/- 0.021 +/- 0.062)% and B (D+ → K -pi+pi+) = (9.157 +/- 0.059 +/- 0.125)%, where the first uncertainty is statistical, the second is systematic errors. Using an independent determination of the integrated luminosity, we also extract the cross sections sigma(e +e- → D 0D¯0) = (3.650 +/- 0.017 +/- 0.083) nb and sigma(e+ e- → D+ D-) = (2.920 +/- 0.018 +/- 0.062) nb at a center of mass energy, Ecm = 3774 +/- 1 MeV.

  5. Absolute blood velocity measured with a modified fundus camera

    NASA Astrophysics Data System (ADS)

    Duncan, Donald D.; Lemaillet, Paul; Ibrahim, Mohamed; Nguyen, Quan Dong; Hiller, Matthias; Ramella-Roman, Jessica

    2010-09-01

    We present a new method for the quantitative estimation of blood flow velocity, based on the use of the Radon transform. The specific application is for measurement of blood flow velocity in the retina. Our modified fundus camera uses illumination from a green LED and captures imagery with a high-speed CCD camera. The basic theory is presented, and typical results are shown for an in vitro flow model using blood in a capillary tube. Subsequently, representative results are shown for representative fundus imagery. This approach provides absolute velocity and flow direction along the vessel centerline or any lateral displacement therefrom. We also provide an error analysis allowing estimation of confidence intervals for the estimated velocity.

  6. Absolute measurement of undulator radiation in the extreme ultraviolet

    NASA Astrophysics Data System (ADS)

    Maezawa, H.; Mitani, S.; Suzuki, Y.; Kanamori, H.; Tamamushi, S.; Mikuni, A.; Kitamura, H.; Sasaki, T.

    1983-04-01

    The spectral brightness of undulator radiation emitted by the model PMU-1 incorporated in the SOR-RING, the dedicated synchrotron radiation source in Tokyo, has been studied in the extreme ultraviolet region from 21.6 to 72.9 eV as a function of the electron energy γ, the field parameter K, and the angle of observation ϴ in the absolute scale. A series of measurements covering the first and the second harmonic component of undulator radiation was compared with the fundamental formula λ n= {λ 0}/{2nγ 2}( {1+K 2}/{2}+γϴ 2 and the effects of finite emittance were studied. The brightness at the first peak was smaller than the theoretical value, while an enhanced second harmonic component was observed.

  7. Absolute measures of the completeness of the fossil record

    NASA Technical Reports Server (NTRS)

    Foote, M.; Sepkoski, J. J. Jr; Sepkoski JJ, J. r. (Principal Investigator)

    1999-01-01

    Measuring the completeness of the fossil record is essential to understanding evolution over long timescales, particularly when comparing evolutionary patterns among biological groups with different preservational properties. Completeness measures have been presented for various groups based on gaps in the stratigraphic ranges of fossil taxa and on hypothetical lineages implied by estimated evolutionary trees. Here we present and compare quantitative, widely applicable absolute measures of completeness at two taxonomic levels for a broader sample of higher taxa of marine animals than has previously been available. We provide an estimate of the probability of genus preservation per stratigraphic interval, and determine the proportion of living families with some fossil record. The two completeness measures use very different data and calculations. The probability of genus preservation depends almost entirely on the Palaeozoic and Mesozoic records, whereas the proportion of living families with a fossil record is influenced largely by Cenozoic data. These measurements are nonetheless highly correlated, with outliers quite explicable, and we find that completeness is rather high for many animal groups.

  8. Absolute Measurements of Optical Oscillator Strengths of Xe

    NASA Astrophysics Data System (ADS)

    Gibson, N. D.

    1998-05-01

    The dramatically increased interest in Xe as a discharge medium for the efficient generation of UV radiation, and Xe use in high technology applications such as flat panel displays for laptop computer screens and home TV and theater applications, has created the need for significantly more accurate oscillator strength data. Modeling of plasma processing systems and lighting discharges critically depends on accurate, precise atomic data. We are measuring the optical oscillator strengths of several Xe resonance lines. These measurements use a 900 eV collimated electron beam to excite the Xe atoms. In the method of self absorption used here, the transmission of the emitted radiation is measured as a function of the gas density. The measured oscillator strengths are proportional to the distance between the electron beam and the fixed aperture of the spectrometer-detector system. Since the theoretical form of the transmission function is well understood, there are few systematic errors. Absolute errors as low as 3-4% can be obtained.

  9. Absolute Thermal SST Measurements over the Deepwater Horizon Oil Spill

    NASA Astrophysics Data System (ADS)

    Good, W. S.; Warden, R.; Kaptchen, P. F.; Finch, T.; Emery, W. J.

    2010-12-01

    Climate monitoring and natural disaster rapid assessment require baseline measurements that can be tracked over time to distinguish anthropogenic versus natural changes to the Earth system. Disasters like the Deepwater Horizon Oil Spill require constant monitoring to assess the potential environmental and economic impacts. Absolute calibration and validation of Earth-observing sensors is needed to allow for comparison of temporally separated data sets and provide accurate information to policy makers. The Ball Experimental Sea Surface Temperature (BESST) radiometer was designed and built by Ball Aerospace to provide a well calibrated measure of sea surface temperature (SST) from an unmanned aerial system (UAS). Currently, emissive skin SST observed by satellite infrared radiometers is validated by shipborne instruments that are expensive to deploy and can only take a few data samples along the ship track to overlap within a single satellite pixel. Implementation on a UAS will allow BESST to map the full footprint of a satellite pixel and perform averaging to remove any local variability due to the difference in footprint size of the instruments. It also enables the capability to study this sub-pixel variability to determine if smaller scale effects need to be accounted for in models to improve forecasting of ocean events. In addition to satellite sensor validation, BESST can distinguish meter scale variations in SST which could be used to remotely monitor and assess thermal pollution in rivers and coastal areas as well as study diurnal and seasonal changes to bodies of water that impact the ocean ecosystem. BESST was recently deployed on a conventional Twin Otter airplane for measurements over the Gulf of Mexico to access the thermal properties of the ocean surface being affected by the oil spill. Results of these measurements will be presented along with ancillary sensor data used to eliminate false signals including UV and Synthetic Aperture Radar (SAR

  10. Thickness measurement locations of mechanical integrity

    SciTech Connect

    Decker, J.R.; Rivas, N.

    1996-07-01

    This paper will describe the importance of establishing thickness measurement location (TNE) criteria. It will also seek to quantify the frequency of inspections and review the methods for establishing techniques to ensure reliability and repeatability of inspections at TMLs using qualified inspectors. Also discussed will be the most useful way to document the results of an inspection and how to effectively maintain consistency in the mechanical integrity program. It reviews different methods of inspection and uses lessons learned from in-service experience with numerous mechanical projects in the petrochemical industry. The importance of qualified inspectors, quality inspection, electronic data acquisition and electronic data storage will be discussed.

  11. EMR Gage Would Measure Coal Thickness Accurately

    NASA Technical Reports Server (NTRS)

    King, J. D.; Rollwitz, W. L.

    1982-01-01

    Laboratory tests indicate electron magnetic resonance (EMR) would be effective in measuring thickness of coal overlying rock substrate. In prototype dual-frequency EMR system, Sample is irradiated by two radio frequencies. Signals are mixed, producing sum and difference output frequencies that are detected by receiver. Magnetic field is varied to scan resonant spot through sample. In system designed for field use, electromagnet is U-shaped, so that sample can be adjacent to, rather than inside the probe. Same coil is used for transmitting and receiving.

  12. Absolute activity measurement of radon gas at IRA-METAS

    NASA Astrophysics Data System (ADS)

    Spring, Philippe; Nedjadi, Youcef; Bailat, Claude; Triscone, Gilles; Bochud, François

    2006-12-01

    This paper describes the system of the Swiss national metrological institute (IRA-METAS) for the absolute standardisation of radon gas. This method relies on condensing radon under vacuum conditions within a specified cold area using a cryogenerator, and detecting its alpha particles with an ion-implanted silicon detector, through a very accurately defined solid angle. The accuracy of this defined solid angle standardisation technique was corroborated by another primary measurement method involving 4 πγ NaI(Tl) integral counting and Monte Carlo efficiency calculations. The 222Rn standard submitted by IRA-METAS to the Système International de Référence (SIR) at the Bureau International des Poids et Mesures (BIPM) has also been found to be consistent with an analogous standard submitted by the German national metrological institute (PTB). IRA-METAS is able to deliver radon standards, with activities ranging from a few kBq to 350 kBq, in NIST-Type ampoules, and glass or steel containers usable for calibrating radon-measuring instruments.

  13. Embedded north-seeker for automatic absolute magnetic DI measurements

    NASA Astrophysics Data System (ADS)

    Gonsette, Alexandre; Rasson, Jean

    2014-05-01

    In magnetic observatory Earth magnetic field is recorded with a resolution of 0.1nT for 1min sampling (new standards impose 1pT for 1s sampling). The method universally adopted for measuring it is a combination of three instruments. Vectorial magnetometer (variometer) records variations of the three components around a reference value or a baseline. A proton or an overhauser magnetometer is an absolute instrument able to measure the modulus of the field and used to determine the F component baseline of the variometer. The declination and inclination baselines require a manual procedure to be computed. An operator manipulates a non-magnetic theodolite (also called a DIFlux) to measure the D and I angles in different configurations with a resolution of a few arcsec. The AutoDIF is a non-magnetic automatic DIFlux using the same protocol as the manual procedure. The declination defined according to the true north is determined by means of a target pointing system. Even if the technique is fast and accurate, it becomes problematic in case of unmanned deployment. In particular the area between the target and the DIFlux is out of control. Snow storm, fog, vegetation or condensation on windows are examples of perturbation preventing for finding the target. It is obvious in case of (future) seafloor observatories. A FOG based north-seeker has been implemented and mounted on the AutoDIF. The first results using a low cost gyro don't meet the Intermagnet specifications yet but are however hopeful. A 0.1° standard deviation has been reached and statistically reduced to 0.01° after less than two days in laboratory. The magnetic disturbance of the sensor is taken into account and compensated by the measurement protocol.

  14. a Portable Apparatus for Absolute Measurements of the Earth's Gravity.

    NASA Astrophysics Data System (ADS)

    Zumberge, Mark Andrew

    We have developed a new, portable apparatus for making absolute measurements of the acceleration due to the earth's gravity. We use the method of interferometrically determining the acceleration of a freely falling corner -cube prism. The falling object is surrounded by a chamber which is driven vertically inside a fixed vacuum chamber. This falling chamber is servoed to track the falling corner -cube to shield it from drag due to background gas. In addition, the drag-free falling chamber removes the need for a magnetic release, shields the falling object from electrostatic forces, and provides a means of both gently arresting the falling object and quickly returning it to its start position, to allow rapid acquisition of data. A synthesized long period isolation device reduces the noise due to seismic oscillations. A new type of Zeeman laser is used as the light source in the interferometer, and is compared with the wavelength of an iodine stabilized laser. The times of occurrence of 45 interference fringes are measured to within 0.2 nsec over a 20 cm drop and are fit to a quadratic by an on-line minicomputer. 150 drops can be made in ten minutes resulting in a value of g having a precision of 3 to 6 parts in 10('9). Systematic errors have been determined to be less than 5 parts in 10('9) through extensive tests. Three months of gravity data have been obtained with a reproducibility ranging from 5 to 10 parts in 10('9). The apparatus has been designed to be easily portable. Field measurements are planned for the immediate future. An accuracy of 6 parts in 10('9) corresponds to a height sensitivity of 2 cm. Vertical motions in the earth's crust and tectonic density changes that may precede earthquakes are to be investigated using this apparatus.

  15. Preliminary OARE absolute acceleration measurements on STS-50

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James

    1993-01-01

    On-orbit Orbital Acceleration Research Experiment (OARE) data on STS-50 was examined in detail during a 2-day time period. Absolute acceleration levels were derived at the OARE location, the orbiter center-of-gravity, and at the STS-50 spacelab Crystal Growth Facility. The tri-axial OARE raw acceleration measurements (i.e., telemetered data) during the interval were filtered using a sliding trimmed mean filter in order to remove large acceleration spikes (e.g., thrusters) and reduce the noise. Twelve OARE measured biases in each acceleration channel during the 2-day interval were analyzed and applied to the filtered data. Similarly, the in situ measured x-axis scale factors in the sensor's most sensitive range were also analyzed and applied to the data. Due to equipment problem(s) on this flight, both y- and z- axis sensitive range scale factors were determined in a separate process (using the OARE maneuver data) and subsequently applied to the data. All known significant low-frequency corrections at the OARE location (i.e., both vertical and horizontal gravity-gradient, and rotational effects) were removed from the filtered data in order to produce the acceleration components at the orbiter's center-of-gravity, which are the aerodynamic signals along each body axes. Results indicate that there is a force of unknown origin being applied to the Orbiter in addition to the aerodynamic forces. The OARE instrument and all known gravitational and electromagnetic forces were reexamined, but none produce the observed effect. Thus, it is tentatively concluded that the Orbiter is creating the environment observed.

  16. ATLAS ALFA—measuring absolute luminosity with scintillating fibres

    NASA Astrophysics Data System (ADS)

    Franz, S.; Barrillon, P.

    2009-10-01

    ALFA is a high-precision scintillating fibre tracking detector under construction for the absolute determination of the LHC luminosity at the ATLAS interaction point. This detector, mounted in so-called Roman Pots, will track protons elastically scattered under μrad angles at IP1.In total there are four pairs of vertically arranged detector modules which approach the LHC beam axis to mm distance. Each detector module consists of ten layers of two times 64 scintillating fibres each (U and V planes). The fibres are coupled to 64 channels Multi-Anodes PhotoMultipliers Tubes read out by compact front-end electronics. Each detector module is complemented by so-called overlap detectors: Three layers of two times 30 scintillating fibres which will be used to measure the relative positioning of two vertically arranged main detectors. The total number of channels is about 15000. Conventional plastic scintillator tiles are mounted in front of the fibre detectors and will serve as trigger counter. The extremely restricted space inside the pots makes the coupling to the read out devices very challenging. Several technologies have been tested in a beam at DESY and a cosmic-ray setup at CERN. A possible upgrade of the photo detection could consist in the replacement of the PMT by Geiger-mode avalanche photodiodes. Preliminary tests are being performed comparing the performance of these devices with the ones of the PMTs.

  17. Interpretation of the Arcade 2 Absolute Sky Brightness Measurement

    NASA Technical Reports Server (NTRS)

    Seiffert, M.; Fixsen, D. J.; Kogut, A.; Levin, S. M.; Limon, M.; Lubin, P. M.; Mirel, P.; Singal, J.; Villela, T.; Wollack, E.; Wuensche, C. A.

    2011-01-01

    We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon flight of the ARCADE 2 instrument, along with previous measurements at other frequencies to constrain models of extragalactic emission. Such emission is a combination of the cosmic microwave background (CMB) monopole, Galactic foreground emission, the integrated contribution of radio emission from external galaxies, any spectral distortions present in the CMB, and any other extragalactic source. After removal of estimates of foreground emission from our own Galaxy, and an estimated contribution of external galaxies, we present fits to a combination of the flat-spectrum CMB and potential spectral distortions in the CMB. We find 217 upper limits to CMB spectral distortions of u < 6x10(exp -4) and [Y(sub ff)] < 1x10(exp -4). We also find a significant detection of a residual signal beyond that, which can be explained by the CMB plus the integrated radio emission from galaxies estimated from existing surveys. This residual signal may be due to an underestimated galactic foreground contribution, an unaccounted for contribution of a background of radio sources, or some combination of both. The residual signal is consistent with emission in the form of a power law with amplitUde 18.4 +/- 2.1 K at 0.31 GHz and a spectral index of -2.57 +/- 0.05.

  18. Absolute Measurements Of Methane On Mars: The Current Status.

    NASA Astrophysics Data System (ADS)

    Mumma, Michael J.; Villanueva, G. L.; Novak, R. E.; Hewagama, T.; Bonev, B. P.; DiSanti, M. A.; Smith, M. D.

    2008-09-01

    Our study of methane on Mars now extends over three Mars years, sampling a wide range of seasons with significant spatial coverage. Three spectrometer-telescope combinations were used. With the spectrometer slit oriented North-South on the planet, we obtain simultaneous spectra at latitudes along the central meridian. Successive longitudes are sampled as the planet rotates, and the combination then permits partial mapping of the planet. We earlier reported differential detections of methane and water on Mars. Here, we present absolute extractions of methane, based on improved analytical procedures developed since 2005. We now identify and correct instrumental effects such as variations in resolving power along the slit, second-order optical fringe removal, and correction of (minor) internal scattered light. We synthesize the fully-resolved terrestrial transmittance spectrum, convolve it to the instrumental resolution, and subtract it from the measured Mars-Earth spectrum. Fraunhofer lines are removed from the residual Mars spectra along with spectral lines of water and of (newly identified by us) carbon dioxide isotopomers. The residuals are then inspected for signatures of methane and other possible trace constituents such as HDO and H2O (Villanueva et al., this Conference). On certain dates, the residual spectra display spectral lines at the Doppler-shifted positions expected for methane on Mars. The positive indications favor certain seasons (e.g., Ls = 121° & 155°) and locations. Mixing ratios derived from those residuals (up to 60 ppb) greatly exceed upper limits obtained at other seasons (e.g., < 3ppb at Ls = 17°) these variations could be consistent with episodic release. The CH4 spatial extent requires transport over large distances (coupled with eddy diffusion), and destruction lifetimes of order one year. Details will be presented and implications will be discussed. This work was supported by NASA's Astrobiology, Planetary Astronomy, and Postdoctoral

  19. Large-Scale Measurement of Absolute Protein Glycosylation Stoichiometry.

    PubMed

    Sun, Shisheng; Zhang, Hui

    2015-07-07

    Protein glycosylation is one of the most important protein modifications. Glycosylation site occupancy alteration has been implicated in human diseases and cancers. However, current glycoproteomic methods focus on the identification and quantification of glycosylated peptides and glycosylation sites but not glycosylation occupancy or glycoform stoichiometry. Here we describe a method for large-scale determination of the absolute glycosylation stoichiometry using three independent relative ratios. Using this method, we determined 117 absolute N-glycosylation occupancies in OVCAR-3 cells. Finally, we investigated the possible functions and the determinants for partial glycosylation.

  20. Absolute Hugoniot measurements for CH foams in the 1.5-8 Mbar range

    NASA Astrophysics Data System (ADS)

    Aglitskiy, Y.; Velikovich, A. L.; Schmitt, A. J.; Karasik, M.; Serlin, V.; Weaver, J. L.; Oh, J.; Obenschain, S. P.

    2016-10-01

    We report the absolute Hugoniot measurements for dry CH foams at 10% of solid polystyrene density. The 400 μm thick, 500 μm wide planar foam slabs covered with a 10 μm solid plastic ablator were driven with 4 ns long Nike KrF laser pulses whose intensity was varied between 10 and 50 TW/cm2. The trajectories of the shock front and the ablative piston, as well as the rarefaction fan emerging after the shock breakout from the rear surface of the target were clearly observed using the side-on monochromatic x-ray imaging radiography. From these measurements the shock density compression ratio and the shock pressure are evaluated directly. The observed compression ratios varied between 4 and 8, and the corresponding shock pressures - between 1.5 and 8 Mbar. The data was simulated with the FASTRAD3D hydrocode, using standard models of inverse bremsstrahlung absorption, flux-limited thermal conduction, and multi-group radiation diffusion. The demonstrated diagnostics technique applied in a cryo experiment would make it possible to make the first absolute Hugoniot measurements for liquid deuterium or DT-wetted CH foams, which is relevant for designing the wetted-foam indirect-drive ignition targets for NIF. This work was supported by the US DOE/NNSA.

  1. Validation of Terahertz coating thickness measurements using X-ray microtomography.

    PubMed

    Russe, Isabelle-Sophie; Brock, Daniela; Knop, Klaus; Kleinebudde, Peter; Zeitler, J Axel

    2012-12-03

    Terahertz pulsed imaging (TPI) is a recently developed nondestructive and noncontact method to measure the coating thickness of coated pharmaceutical tablets. The method requires no calibration in order to resolve the coating structure of tablets. The relative coating thickness over a tablet surface or between different tablets of the same batch can be determined with high precision. However, in order to determine the absolute coating thickness accurately the refractive index, n, of the coating layer needs to be known. For all published studies to date the value of n was based on estimates or bulk measurements, which were based on the assumption that n is constant for a given coating formulation. We have developed a measurement technique using X-ray microtomography to independently quantify the coating thickness. These data were then used to validate the terahertz imaging results, and we found that the intertablet variation of n for coating layers of 25-270 μm thickness is less than 4% and that there is less than 3% intratablet variation in n. Based on our results we estimate that, depending on the pigment content, the absolute value of n in a typical pharmaceutical coating formulation will be in the range of 1.45 < n < 2.01. We conclude that TPI is a robust technique and that, due to its very simple measurement principle, it is an ideal measurement technique to quantify the coating thickness in process control and quality monitoring applications.

  2. Capacitive Measurement Of Coating Thickness On Carbon Fibers

    NASA Technical Reports Server (NTRS)

    Eftekhari, Abe; Chapman, John J.

    1994-01-01

    Technique for gauging coating thickness during prepreg processing of carbon fibers developed. Technique based on measurement of capacitance of cylindrical condenser through which bundle of prepregged fibers passed axially. Empirical results indicate capacitance linearly related to thickness of polymer coat on fibers in bundle. Capacitive transducer used successfully to measure thickness of polymer coats on several test bundles of fibers under static conditions.

  3. Absolute Gravity Measurements with the FG5#215 in Czech Republic, Slovakia and Hungary

    NASA Astrophysics Data System (ADS)

    Pálinkás, V.; Kostelecký, J.; Lederer, M.

    2009-04-01

    Since 2001, the absolute gravimeter FG5#215 has been used for modernization of national gravity networks in Czech Republic, Slovakia and Hungary. Altogether 37 absolute sites were measured at least once. In case of 29 sites, the absolute gravity has been determined prior to the FG5#215 by other accurate absolute meters (FG5 or JILA-g). Differences between gravity results, which reach up to 25 microgal, are caused by random and systematic errors of measurements, variations of environmental effects (mainly hydrological effects) and by geodynamics. The set of achieved differences is analyzed for potential hydrological effects based on global hydrology models and systematic errors of instrumental origin. Systematic instrumental errors are evaluated in context with accomplished international comparison measurements of absolute gravimeters in Sèvres and Walferdange organized by the Bureau International des Poids et Measures and European Center for Geodynamics and Seismology, respectively.

  4. Absolute Measurement of Tilts via Fourier Analysis of Interferograms

    NASA Technical Reports Server (NTRS)

    Toland, Ronald W.

    2004-01-01

    The Fourier method of interferogram analysis requires the introduction of a constant tilt into the interferogram to serve as a carrier signal for information on the figure of the surface under test. This tilt is usually removed in the first steps of analysis and ignored thereafter. However, in the problem of aligning optical components and systems, knowledge of part orientation is crucial to proper instrument performance. This paper outlines an algorithm which uses the normally ignored carrier signal in Fourier analysis to compute an absolute tilt (orientation) of the test surface. We also provide a brief outline of how this technique, incorporated in a rotating Twyman-Green interferometer, can be used in alignment and metrology of optical systems.

  5. Absolute Measurement of Tilts via Fourier Analysis of Interferograms

    NASA Technical Reports Server (NTRS)

    Toland, Ronald W.

    2004-01-01

    The Fourier method of interferogram analysis requires the introduction of a constant tilt into the inteferogram to serve as a 'carrier signal' for information on the figure of the surface under test. This tilt is usually removed in the first steps of analysis and ignored thereafter. However, in the problem of aligning optical components and systems, knowledge of part orientation is crucial to proper instrument performance. This paper outlines an algorithm which uses the normally ignored carrier signal in Fourier analysis to compute an absolute tilt (orientation) of the test surface. We also provide a brief outline of how this technique, incorporated in a rotating Twyman-Green interferometer, can be used in alignment and metrology of optical systems.

  6. Thickness measurement of sample in diamond anvil cell.

    PubMed

    Li, Ming; Gao, Chunxiao; Peng, Gang; He, Chunyuan; Hao, Aimin; Huang, Xiaowei; Zhang, Dongmei; Yu, Cuiling; Ma, Yanzhang; Zou, Guangtian

    2007-07-01

    We report on an original method that measures sample thickness in a diamond anvil cell under high pressures. The method is based on two hypotheses: completely plastic deformation on the gasket and completely elastic deformation of the diamonds. This method can further eliminate the effect of diamond deformation on the thickness measurement of a sample, which permits us to measure the thickness of alumina up to 41.4 GPa.

  7. Measuring the Thickness of a Transparent Ring with a Laser

    ERIC Educational Resources Information Center

    Leung, Alfred F.

    2007-01-01

    There seems to be no reasonable way to measure the thickness of a narrow-mouth glass bottle. One can measure the outer and inner diameters of the mouth with a ruler or a pair of calipers and then calculate the thickness. However, this measurement might be interfered with by the threads at the mouth. Furthermore, it is uncertain whether the…

  8. [Study on plastic film thickness measurement by integral spectrum method].

    PubMed

    Qiu, Chao; Sun, Xiao-Gang

    2013-01-01

    Band integral transmission was defined and plastic film thickness measurement model was built by analyzing the intensity variation when the light passes plastic film, after the concept of band Lambert Law was proposed. Polypropylene film samples with different thickness were taken as the research object, and their spectral transmission was measured by the spectrometer. The relationship between thickness and band integral transmission is fitted using the model mentioned before. The feasibility of developing new broad band plastic film thickness on-line measurement system based on this method was analysed employing the ideal blackbody at temperature of 500 K. The experimental results indicate that plastic film thickness will be measured accurately by integral spectrum method. Plastic film thickness on-line measurement system based on this method will hopefully solve the problems of that based on dual monochromatic light contrast method, such as low accuracy, poor universality and so on.

  9. Ultrasonic thickness measuring and imaging system and method

    DOEpatents

    Bylenok, Paul J.; Patmos, William M.; Wagner, Thomas A.; Martin, Francis H.

    1992-08-04

    An ultrasonic thickness measuring and imaging system uses an ultrasonic fsed beam probe for measuring thickness of an object, such as a wall of a tube, a computer for controlling movement of the probe in a scanning pattern within the tube and processing an analog signal produced by the probe which is proportional to the tube wall thickness in the scanning pattern, and a line scan recorder for producing a record of the tube wall thicknesses measured by the probe in the scanning pattern. The probe is moved in the scanning pattern to sequentially scan circumferentially the interior tube wall at spaced apart adjacent axial locations. The computer processes the analog signal by converting it to a digital signal and then quantifies the digital signal into a multiplicity of thickness points with each falling in one of a plurality of thickness ranges corresponding to one of a plurality of shades of grey. From the multiplicity of quantified thickness points, a line scan recorder connected to the computer generates a pictorial map of tube wall thicknesses with each quantified thickness point thus being obtained from a minute area, e.g. 0.010 inch by 0.010 inch, of tube wall and representing one pixel of the pictorial map. In the pictorial map of tube wall thicknesses, the pixels represent different wall thicknesses having different shades of grey.

  10. Ultrasonic thickness measuring and imaging system and method

    DOEpatents

    Bylenok, Paul J.; Patmos, William M.; Wagner, Thomas A.; Martin, Francis H.

    1992-01-01

    An ultrasonic thickness measuring and imaging system uses an ultrasonic fsed beam probe for measuring thickness of an object, such as a wall of a tube, a computer for controlling movement of the probe in a scanning pattern within the tube and processing an analog signal produced by the probe which is proportional to the tube wall thickness in the scanning pattern, and a line scan recorder for producing a record of the tube wall thicknesses measured by the probe in the scanning pattern. The probe is moved in the scanning pattern to sequentially scan circumferentially the interior tube wall at spaced apart adjacent axial locations. The computer processes the analog signal by converting it to a digital signal and then quantifies the digital signal into a multiplicity of thickness points with each falling in one of a plurality of thickness ranges corresponding to one of a plurality of shades of grey. From the multiplicity of quantified thickness points, a line scan recorder connected to the computer generates a pictorial map of tube wall thicknesses with each quantified thickness point thus being obtained from a minute area, e.g. 0.010 inch by 0.010 inch, of tube wall and representing one pixel of the pictorial map. In the pictorial map of tube wall thicknesses, the pixels represent different wall thicknesses having different shades of grey.

  11. Absolute measurements of the densities of silicon crystals in vacuum for a determination of the Avogadro constant

    SciTech Connect

    Fujii, K.; Tanaka, M.; Nezu, Y.

    1994-12-31

    Absolute measurements of the densities of 1-kg single-crystal silicon spheres have been performed for a determination of the Avogadro constant. A scanning type optical interferometer was used to measure the diameters of the spheres in vacuum, and the volumes were obtained by fitting the diameters to a series of spherical harmonics. Thickness of oxide layers on the surfaces of the spheres has been determined by using an ellipsometer to evaluate the effect on the density. Total uncertainties of the densities are estimated to be 0.1 ppm.

  12. Interferometric System for Measuring Thickness of Sea Ice

    NASA Technical Reports Server (NTRS)

    Hussein, Ziad; Jordan, Rolando; McDonald, Kyle; Holt, Benjamin; Huang, John; Kugo, Yasuo; Ishimaru, Akira; Jaruwatanadilok, Semsak; Akins, Torry; Gogineni, Prasad

    2006-01-01

    The cryospheric advanced sensor (CAS) is a developmental airborne (and, potentially, spaceborne) radar-based instrumentation system for measuring and mapping the thickness of sea ice. A planned future version of the system would also provide data on the thickness of snow covering sea ice. Frequent measurements of the thickness of polar ocean sea ice and its snow cover on a synoptic scale are critical to understanding global climate change and ocean circulation.

  13. Measurement of dielectric-film thickness at low density plasma

    NASA Astrophysics Data System (ADS)

    Jeon, Sang-Bum; Kim, Dong-Hwan; Kim, Jin-Yong; Paek, Se-Yeol; Chung, Chin-Wook

    2016-09-01

    The measurement system of dielectric-film thickness was improved to measure thin-film at low density plasma. There are three improvements than previous method, which is electrical measurement of dielectric-film thickness using R-C sheath model. First, the frequency of input voltage was decreased to reduce the ratio of the dielectric-film impedance to sheath impedance. Second, three different frequencies were used to overcome the inaccuracy of measured phase; only amplitudes of measured current were used to obtain a film thickness. Third, the notch filter was used for sensing current instead of the resistor to improve the signal to noise ratio. Using this method, dielectric-film thickness was well measured at low density plasma (thickness: 300, sheath impedance: 100 200 k Ω) .

  14. Absolute beam emittance measurements at RHIC using ionization profile monitors

    SciTech Connect

    Minty, M.; Connolly, R; Liu, C.; Summers, T.; Tepikian, S.

    2014-08-15

    In the past, comparisons between emittance measurements obtained using ionization profile monitors, Vernier scans (using as input the measured rates from the zero degree counters, or ZDCs), the polarimeters and the Schottky detectors evidenced significant variations of up to 100%. In this report we present studies of the RHIC ionization profile monitors (IPMs). After identifying and correcting for two systematic instrumental errors in the beam size measurements, we present experimental results showing that the remaining dominant error in beam emittance measurements at RHIC using the IPMs was imprecise knowledge of the local beta functions. After removal of the systematic errors and implementation of measured beta functions, precise emittance measurements result. Also, consistency between the emittances measured by the IPMs and those derived from the ZDCs was demonstrated.

  15. Absolute bunch length measurement using coherent diffraction radiation.

    PubMed

    Veronese, Marco; Appio, Roberto; Craievich, Paolo; Penco, Giuseppe

    2013-02-15

    The longitudinal electron beam properties are of crucial importance for many types of frontier accelerators, from storage rings to free electron lasers and energy recovery linacs. For the online control of the machine and its stable operation, nondestructive shot by shot bunch length measurements are needed. Among the various instrumentations proposed and installed in accelerators worldwide, the ones based on the measurement of the coherent radiation power represent the simplest and the more robust tools for operational control. The major limitation of these systems is that they usually can provide only relative bunch length estimation. In this Letter we present a novel experimental methodology to self-calibrate a simple equipment based on diffraction radiation from a gap providing a measurement of the second order moment of the longitudinal distribution. We present the theoretical basis of the proposed approach and validate it through a detailed campaign of measurements.

  16. Absolute viscosity measured using instrumented parallel plate system

    NASA Technical Reports Server (NTRS)

    Broyles, H. H.

    1967-01-01

    An automatic system measures the true average shear viscosity of liquids and viscoelastic materials, using the parallel plate method and automatically displays the results on a graphic record. This eliminates apparatus setup and extensive calculations.

  17. Laser Ultrasonic Thickness Measurements of Very Thick Walls at High Temperatures

    SciTech Connect

    Kruger, S. E.; Lord, M.; Monchalin, J.-P.

    2006-03-06

    Laser-ultrasonics presents many advantages compared to conventional ultrasonics, but is, generally, considered as less sensitive. As a consequence, laser-ultrasonics should not be adequate for ultrasonic measurements in coarse microstructure materials or measurements of large thicknesses. However, since the generated waves extend to very low frequencies, measurements in such conditions can be successfully performed if a photorefractive interferometer sensitive also to these low frequencies and properly balanced is used for detection. This is demonstrated by measurements of thicknesses up to 100 mm (4'') for various steel grades and at temperatures up to 1250 deg. C.

  18. A method to estimate the absolute ultrasonic nonlinearity parameter from relative measurements.

    PubMed

    Kim, Jongbeom; Song, Dong-Gi; Jhang, Kyung-Young

    2017-02-17

    The ultrasonic nonlinearity parameter, β, is determined from the displacement amplitude of the second-order harmonic frequency component generated during the propagation of ultrasonic waves through a material. This parameter is generally referred to as the absolute parameter. Meanwhile, it is difficult to measure the small displacement amplitude of the second-order harmonic component; therefore, most studies measure the relative parameter determined from the detected signal amplitude. However, for quantitative assessment of material degradation, the absolute parameter is still required. This study proposes a method to estimate the absolute parameter for damaged material by measuring the relative parameter. This method is based on the fact that the fractional ratio of the relative parameters between different materials is identical to that of the absolute parameters after compensation for material dependent differences such as the wavenumber and detection-sensitivity. In order to experimentally verify the method, the relative parameters of heat-treated Al6061-T6 alloy specimens with different aging times were measured to compare with absolute parameters directly measured by piezo-electric detection. The results show that the fluctuations of both parameters with respect to aging time were very similar to each other, and that the absolute parameters estimated by the proposed method were in good agreement with those measured directly.

  19. Optical thickness measurement of mask blank glass plate by the excess fraction method using a wavelength-tuning interferometer

    NASA Astrophysics Data System (ADS)

    Kim, Yangjin; Hibino, Kenichi; Sugita, Naohiko; Mitsuishi, Mamoru

    2013-10-01

    The absolute optical thickness of a 140-mm2 mask blank glass plate 3.1 mm thickness was measured by three-surface interferometry using a wavelength-tuning Fizeau interferometer. The interference order was determined by the excess fraction method. The wavelength of a tunable laser diode was scanned linearly from 632 to 642 nm, and a CCD detector recorded 2000 interference images. Two kinds of optical thicknesses measured by discrete Fourier analysis and phase-shifting were synthesized to obtain the optical thickness with respect to the ordinary refractive index. The optical thickness defined by the group refractive index at the 637 nm central wavelength was measured by wavelength scanning. The optical thickness deviation defined by the ordinary refractive index was measured using tunable phase-shifting. The systematic errors caused by nonlinearity in the wavelength tuning were corrected through correlation analysis between the theoretical and observed interference fringes.

  20. Absolute electron density measurements in the equatorial ionosphere

    NASA Technical Reports Server (NTRS)

    Baker, K. D.; Howlett, L. C.; Rao, N. B.; Ulwick, J. C.; Labelle, J.

    1985-01-01

    Accurate measurement of the electron density profile and its variations is crucial to further progress in understanding the physics of the disturbed equatorial ionosphere. To accomplish this, a plasma frequency probe was included in the payload complement of two rockets flown during the Condor rocket campaign conducted from Peru in March 1983. This paper presents density profiles of the disturbed equatorial ionosphere from a night-time flight in which spread-F conditions were present and from a day-time flight during strong electrojet conditions. Results from both flights are in excellent agreement with simultaneous radar data in that the regions of highly disturbed plasma coincide with the radar signatures. The spread-F rocket penetrated a topside depletion during both the upleg and downleg. The electrojet measurements showed a profile peaking at 1.3 x 10 to the 5th per cu cm at 106 km, with large scale fluctuations having amplitudes of roughly 10 percent seen only in the upward gradient in electron density. This is in agreement with plasma instability theory. It is further shown that simultaneous measurements by fixed-bias Langmuir probes, when normalized at a single point to the altitude profile of electron density, are inadequate to correctly parameterize the observed enhancements and depletions.

  1. Expectation maximization classification and Laplacian based thickness measurement for cerebral cortex thickness estimation

    NASA Astrophysics Data System (ADS)

    Holden, Mark; Moreno-Vallecillo, Rafael; Harris, Anthony; Gomes, Lavier J.; Diep, Than-Mei; Bourgeat, Pierrick T.; Ourselin, Sébastien

    2007-03-01

    We describe a new framework for measuring cortical thickness from MR human brain images. This involves the integration of a method of tissue classification with one to estimate thickness in 3D. We have determined an additional boundary detection step to facilitate this. The classification stage utlizes the Expectation Maximisation (EM) algorithm to classify voxels associated with the tissue types that interface with cortical grey matter (GM, WM and CSF). This uses a Gaussian mixture and the EM algorithm to estimate the position and and width of the Gaussians that model the intensity distributions of the GM, WM and CSF tissue classes. The boundary detection stage uses the GM, WM and CSF classifications and finds connected components, fills holes and then applies a geodesic distance transform to determine the GM/WM interface. Finally the thickness of the cortical grey matter is estimated by solving Laplace's equation and determining the streamlines that connect the inner and outer boundaries. The contribution of this work is the adaptation of the classification and thickness measurement steps, neither requiring manual initialisation, and also the validation strategy. The resultant algorithm is fully automatic and avoids the computational expense associated with preserving the cortical surface topology. We have devised a validation strategy that indicates the cortical segmentation of a gold standard brain atlas has a similarity index of 0.91, thickness estimation has subvoxel accuracy evaluated using a synthetic image and precision of the combined segmentation and thickness measurement of 1.54mm using three clinical images.

  2. Application of white light Fresnel diffractometry to film thickness measurement.

    PubMed

    Hassani, Khosrow; Ashrafganjoie, Mehdi; Tavassoly, Mohammad Taghi

    2016-03-01

    In this work we present the theoretical background and experimental procedure to measure the thickness of thin films by analyzing Fresnel diffraction patterns obtained from polychromatic illumination of phase-step samples. As examples of this technique, we measured the thicknesses of thin aluminum layers on glass substrates using three different broad-spectrum light sources. The results are in excellent agreement with independent interferometric measurements within less than 5% relative uncertainties.

  3. Absolute distance measurement with an optical feedback interferometer.

    PubMed

    Gouaux, F; Servagent, N; Bosch, T

    1998-10-01

    An important use of the self-mixing effect inside a frequency-modulated single-mode laser diode is in laser velocimetry and range-finding applications. The optical beam reflected by a target and injected into the laser diode cavity modulated by a reshaped current is mixed with the light inside the cavity, causing variations of the optical output power. A theoretical analysis of this effect is proposed, based on the determination of the beat frequencies of the optical power variations, to improve the accuracy of laser distance measurement. A resolution of ?1.5 mm from 50 cm to 2 m is obtained when thermal effects are taken into account.

  4. Method of measuring the thickness of radioactive thin films

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Steinberg, R.; Makinen, M. D.

    1974-01-01

    Thickness monitor consists of proportional X-ray counter coupled to pulse counting system, copper filter over face of counter, rotatable collimator containing radioactive source, and rotatable shutter. Monitor can be used as integral part of neutron generator. It has been used to measure titanium tritide film thicknesses from 0.1 to 30 micrometers.

  5. Stratospheric thickness determined directly from satellite radiance measurements.

    NASA Technical Reports Server (NTRS)

    Quiroz, R. S.; Gelman, M. E.

    1972-01-01

    Discussion of the use of satellite radiance data for determining the thickness of deep stratospheric layers. Empirical regression equations are shown to provide better estimates of stratospheric thickness than do mean weighted temperatures obtained from the Planck equation. The best regression equations were found for thick layers emitting a substantial portion of the CO2-band infrared radiation measured by satellites. By adding the layer thickness to the observed height field for the lower boundary, it is possible to construct constant-pressure maps at very high altitudes.

  6. The study of absolute distance measurement based on the self-mixing interference in laser diode

    NASA Astrophysics Data System (ADS)

    Wang, Ting-ting; Zhang, Chuang

    2009-07-01

    In this work, an absolute distance measurement method based on the self-mixing interference is presented. The principles of the method used three-mirror cavity equivalent model are studied in this paper, and the mathematical model is given. Wavelength modulation of the laser beam is obtained by saw-tooth modulating the infection current of the laser diode. Absolute distance of the external target is determined by Fourier analysis method. The frequency of signal from PD is linearly dependent on absolute distance, but also affected by temperature and fluctuation of current source. A dual-path method which uses the reference technique for absolute distance measurement has been proposed. The theoretical analysis shows that the method can eliminate errors resulting from distance-independent variations in the setup. Accuracy and stability can be improved. Simulated results show that a resolution of +/-0.2mm can be achieved for absolute distance ranging from 250mm to 500mm. In the same measurement range, the resolution we obtained is better than other absolute distance measurement system proposed base on self-mixing interference.

  7. Measurement of choroidal thickness and macular thickness during and after pregnancy

    PubMed Central

    Ulusoy, Döndü Melek; Duru, Necati; Ataş, Mustafa; Altınkaynak, Hasan; Duru, Zeynep; Açmaz, Gökhan

    2015-01-01

    AIM To investigate the effect of pregnancy on subfoveal choroidal thickness (SFCT) and macular thickness in both pregnant and not pregnant healthy women. METHODS Twenty-nine healthy pregnant women in their third trimester and 36 age-matched healthy women were enrolled in a prospective, cross-sectional study. Foveal and parafoveal thickness in the four quadrants and SFCT were measured by optical coherence tomography (OCT) in the healthy pregnant women (i.e. study group) and healthy women (i.e. control group). OCT measurements were again measured 3mo after delivery in the study group. RESULTS Mean SFCT measurements in the control group, pregnant women of the study group, and after delivery of the study group were 320.86±59.18 µm, 387.97±59.91 µm, and 332.40±26.03 µm, respectively. There was a statistically significant difference in the mean SFCT values between pregnant women of the study group and the control group (P=0.000). Foveal and parafoveal thickness values were not statistically significant in either the study or control group. CONCLUSION SFCT increases during pregnancy and returns to normal range in the three months after delivery. Macular thickness does not show any change during pregnancy. PMID:25938049

  8. High-precision absolute distance and vibration measurement with frequency scanned interferometry

    SciTech Connect

    Yang, H.-J.; Deibel, Jason; Nyberg, Sven; Riles, Keith

    2005-07-01

    We report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two multiple-distance-measurement analysis techniques were developed to improve distance precision and to extract the amplitude and frequency of vibrations. Under laboratory conditions, measurement precision of {approx}50 nm was achieved for absolute distances ranging from 0.1 to 0.7 m by use of the first multiple-distance-measurement technique. The second analysis technique has the capability to measure vibration frequencies ranging from 0.1 to 100 Hz with an amplitude as small as a few nanometers without a priori knowledge.

  9. High-precision absolute distance and vibration measurement with frequency scanned interferometry.

    PubMed

    Yang, Hai-Jun; Deibel, Jason; Nyberg, Sven; Riles, Keith

    2005-07-01

    We report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two multiple-distance-measurement analysis techniques were developed to improve distance precision and to extract the amplitude and frequency of vibrations. Under laboratory conditions, measurement precision of approximately 50 nm was achieved for absolute distances ranging from 0.1 to 0.7 m by use of the first multiple-distance-measurement technique. The second analysis technique has the capability to measure vibration frequencies ranging from 0.1 to 100 Hz with an amplitude as small as a few nanometers without a priori knowledge.

  10. Thorough subcells diagnosis in a multi-junction solar cell via absolute electroluminescence-efficiency measurements.

    PubMed

    Chen, Shaoqiang; Zhu, Lin; Yoshita, Masahiro; Mochizuki, Toshimitsu; Kim, Changsu; Akiyama, Hidefumi; Imaizumi, Mitsuru; Kanemitsu, Yoshihiko

    2015-01-16

    World-wide studies on multi-junction (tandem) solar cells have led to record-breaking improvements in conversion efficiencies year after year. To obtain detailed and proper feedback for solar-cell design and fabrication, it is necessary to establish standard methods for diagnosing subcells in fabricated tandem devices. Here, we propose a potential standard method to quantify the detailed subcell properties of multi-junction solar cells based on absolute measurements of electroluminescence (EL) external quantum efficiency in addition to the conventional solar-cell external-quantum-efficiency measurements. We demonstrate that the absolute-EL-quantum-efficiency measurements provide I-V relations of individual subcells without the need for referencing measured I-V data, which is in stark contrast to previous works. Moreover, our measurements quantify the absolute rates of junction loss, non-radiative loss, radiative loss, and luminescence coupling in the subcells, which constitute the "balance sheets" of tandem solar cells.

  11. Stress measurement in thick plates using nonlinear ultrasonics

    NASA Astrophysics Data System (ADS)

    Abbasi, Zeynab; Ozevin, Didem

    2015-03-01

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  12. Stress measurement in thick plates using nonlinear ultrasonics

    SciTech Connect

    Abbasi, Zeynab E-mail: dozevin@uic.edu; Ozevin, Didem E-mail: dozevin@uic.edu

    2015-03-31

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  13. Wide-Band Radar for Measuring Thickness of Sea Ice

    NASA Technical Reports Server (NTRS)

    Gogineni, Prasad; Kanagaratnam, Pannir; Holt, M.

    2008-01-01

    A wide-band penetrating radar system for measuring the thickness of sea ice is under development. The need for this or a similar system arises as follows: Spatial and temporal variations in the thickness of sea ice are important indicators of heat fluxes between the ocean and atmosphere and, hence, are important indicators of climate change in polar regions. A remote-sensing system that could directly measure the thickness of sea ice over a wide thickness range from aboard an aircraft or satellite would be of great scientific value. Obtaining thickness measurements over a wide region at weekly or monthly time intervals would contribute significantly to understanding of changes in the spatial distribution and of the mass balance of sea ice. A prototype of the system was designed on the basis of computational simulations directed toward understanding what signal frequencies are needed to satisfy partly competing requirements to detect both bottom and top ice surfaces, obtain adequate penetration despite high attenuation in the lossy sea-ice medium, and obtain adequate resolution, all over a wide thickness range. The prototype of the system is of the frequency-modulation, continuous-wave (FM-CW) type. At a given time, the prototype functions in either of two frequency-band/operational-mode combinations that correspond to two thickness ranges: a lower-frequency (50 to 250 MHz) mode for measuring thickness greater than about 1 m, and a higher frequency (300 to 1,300 MHz) mode for measuring thickness less than about 1 m. The bandwidth in the higher-frequency (lesser-thickness) mode is adequate for a thickness resolution of 15 cm; the bandwidth in the lower-frequency (greater-thickness) mode is adequate for a thickness resolution of 75 cm. Although a thickness resolution of no more than 25 cm is desired for scientific purposes, the 75-cm resolution was deemed acceptable for the purpose of demonstrating feasibility. The prototype was constructed as a modified version of a

  14. Measurement of the absolute Raman cross section of the optical phonon in silicon

    NASA Astrophysics Data System (ADS)

    Aggarwal, R. L.; Farrar, L. W.; Saikin, S. K.; Aspuru-Guzik, A.; Stopa, M.; Polla, D. L.

    2011-04-01

    The absolute Raman cross section σ of the first-order 519 cm -1 optical phonon in silicon was measured using a small temperature-controlled blackbody for the signal calibration of the Raman system. Measurements were made with a 25-mil thick (001) silicon sample located in the focal plane of a 20-mm effective focal length (EFL) lens using 785-, 1064-, and 1535-nm CW pump lasers for the excitation of Raman scattering. The pump beam was polarized along the [100] axis of the silicon sample. Values of 1.0±0.2×10 -27, 3.6±0.7×10 -28, and 1.1±0.2×10 -29 cm 2 were determined for σ for 785-, 1064-, and 1535-nm excitation, respectively. The corresponding values of the Raman scattering efficiency S are 4.0±0.8×10 -6, 1.4±0.3×10 -6, and 4.4±0.8×10 -8 cm -1 sr -1.The values of the Raman polarizability |d| for 785-, 1064-, and 1535-nm excitation are 4.4±0.4×10 -15, 5.1±0.5×10 -15, and 1.9±0.2×10 -15 cm 2, respectively. The values of 4.4±0.4×10 -15 and 5.1±0.5×10 -15 cm 2 for |d| for 785- and 1064-nm excitation, respectively, are 1.3 and 2.0 times larger than the values of 3.5×10 -15 and 2.5×10 -15 cm 2 calculated by Wendel. The Raman polarizability |d| computed using the density functional theory in the long-wavelength limit is consistent with the general trend of the measured data and Wendel's model.

  15. Optical scanning extrinsic Fabry-Perot interferometer for absolute microdisplacement measurement.

    PubMed

    Li, T; May, R G; Wang, A; Claus, R O

    1997-12-01

    We report an optical-scanning, dual-fiber, extrinsic Fabry-Perot interferometer system for absolute measurement of microdisplacement. The system involves two air-gapped Fabry-Perot cavities, formed by fiber end faces, functioning as sensing and reference elements. Taking the scanning wavelength as an interconverter to compare the gap length of the sensing head with the reference-cavity length yields the absolute measurement of the sensing-cavity length. The measurement is independent of the wavelength-scanning accuracy, and the reference-cavity length can be self-calibrated simply by one's changing the sensing-head length by an accurate value.

  16. Dynamic frequency-domain interferometer for absolute distance measurements with high resolution.

    PubMed

    Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

    2014-11-01

    A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

  17. Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

    SciTech Connect

    Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

    2014-11-15

    A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

  18. Model-based cartilage thickness measurement in the submillimeter range

    SciTech Connect

    Streekstra, G. J.; Strackee, S. D.; Maas, M.; Wee, R. ter; Venema, H. W.

    2007-09-15

    Current methods of image-based thickness measurement in thin sheet structures utilize second derivative zero crossings to locate the layer boundaries. It is generally acknowledged that the nonzero width of the point spread function (PSF) limits the accuracy of this measurement procedure. We propose a model-based method that strongly reduces PSF-induced bias by incorporating the PSF into the thickness estimation method. We estimated the bias in thickness measurements in simulated thin sheet images as obtained from second derivative zero crossings. To gain insight into the range of sheet thickness where our method is expected to yield improved results, sheet thickness was varied between 0.15 and 1.2 mm with an assumed PSF as present in the high-resolution modes of current computed tomography (CT) scanners [full width at half maximum (FWHM) 0.5-0.8 mm]. Our model-based method was evaluated in practice by measuring layer thickness from CT images of a phantom mimicking two parallel cartilage layers in an arthrography procedure. CT arthrography images of cadaver wrists were also evaluated, and thickness estimates were compared to those obtained from high-resolution anatomical sections that served as a reference. The thickness estimates from the simulated images reveal that the method based on second derivative zero crossings shows considerable bias for layers in the submillimeter range. This bias is negligible for sheet thickness larger than 1 mm, where the size of the sheet is more than twice the FWHM of the PSF but can be as large as 0.2 mm for a 0.5 mm sheet. The results of the phantom experiments show that the bias is effectively reduced by our method. The deviations from the true thickness, due to random fluctuations induced by quantum noise in the CT images, are of the order of 3% for a standard wrist imaging protocol. In the wrist the submillimeter thickness estimates from the CT arthrography images correspond within 10% to those estimated from the anatomical

  19. Laser triangulation for liquid film thickness measurements through multiple interfaces.

    PubMed

    Peterson, Jerrod P; Peterson, Richard B

    2006-07-10

    Laser triangulation is used to measure the thickness of a liquid film in a test section consisting of a quartz viewing window, a water layer, and a hydrophobic membrane. The triangulation sensor acquires measurements to the bounding surfaces of the film while peering through multiple interfaces. This allows the difference between the two measurements to constitute the local film thickness. A refraction model is developed and applied to the analysis of data collected from the experiment. For verification, an empirical method is also developed and compared to the analytical approach. The measurement technique is intended to assess the stability of liquid films for use as gas-liquid contactors.

  20. Electrical Noise and the Measurement of Absolute Temperature, Boltzmann's Constant and Avogadro's Number.

    ERIC Educational Resources Information Center

    Ericson, T. J.

    1988-01-01

    Describes an apparatus capable of measuring absolute temperatures of a tungsten filament bulb up to normal running temperature and measuring Botzmann's constant to an accuracy of a few percent. Shows that electrical noise techniques are convenient to demonstrate how the concept of temperature is related to the micro- and macroscopic world. (CW)

  1. Apparatus and method for measuring the thickness of a coating

    DOEpatents

    Carlson, Nancy M.; Johnson, John A.; Tow, David M.; Walter, John B

    2002-01-01

    An apparatus and method for measuring the thickness of a coating adhered to a substrate. An electromagnetic acoustic transducer is used to induce surface waves into the coating. The surface waves have a selected frequency and a fixed wavelength. Interpolation is used to determine the frequency of surface waves that propagate through the coating with the least attenuation. The phase velocity of the surface waves having this frequency is then calculated. The phase velocity is compared to known phase velocity/thickness tables to determine the thickness of the coating.

  2. Measurement of subcutaneous adipose tissue thickness by near-infrared.

    PubMed

    Wang, Yu; Yang, Zeqiang; Hao, Dongmei; Zhang, Song; Yang, Yimin; Zeng, Yanjun

    2013-06-01

    Obesity is strongly associated with the risks of diabetes and cardiovascular disease, and there is a need to measure the subcutaneous adipose tissue (SAT) layer thickness and to understand the distribution of body fat. A device was designed to illuminate the body parts by near-infrared (NIR), measure the backscattered light, and predict the SAT layer thickness. The device was controlled by a single-chip microcontroller (SCM), and the thickness value was presented on a liquid crystal display (LCD). There were 30 subjects in this study, and the measurements were performed on 14 body parts for each subject. The paper investigated the impacts of pressure and skin colour on the measurement. Combining with principal component analysis (PCA) and support vector regression (SVR), the measurement accuracy of SAT layer thickness was 89.1 % with a mechanical caliper as reference. The measuring range was 5-11 mm. The study provides a non-invasive and low-cost technique to detect subcutaneous fat thickness, which is more accessible and affordable compared to other conventional techniques. The designed device can be used at home and in community.

  3. Digital analysis of wind tunnel imagery to measure fluid thickness

    NASA Technical Reports Server (NTRS)

    Easton, Roger L., Jr.; Enge, James

    1992-01-01

    Documented here are the procedure and results obtained from the application of digital image processing techniques to the problem of measuring the thickness of a deicing fluid on a model airfoil during simulated takeoffs. The fluid contained a fluorescent dye and the images were recorded under flash illumination on photographic film. The films were digitized and analyzed on a personal computer to obtain maps of the fluid thickness.

  4. Measuring for thickness distribution of recording layer of PLH

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Chun; Guo, Lurong; Guo, Yongkang

    1991-07-01

    An interference microscope is employed to take a photo of the interfering fringes, and its density is analyzed by a computer image system to measure the thickness distribution of a photolithographic hologram (PLH). This method is much more simple than that of SEM. The theory of measuring is presented in the paper. The authors measured the distributions of photolithographic gratings before and after the etching process. Comparing both the thickness distributions of corresponding recording layers, some primary rules of pattern transfer process by etching were identified.

  5. Measurement of sheath thickness at a floating potential

    SciTech Connect

    Han, Hyung-Sik; Lee, Hyo-Chang; Oh, Se-Jin; Chung, Chin-Wook

    2014-02-15

    In a cylindrical Langmuir probe measurement, ion current is collected from the surface of the sheath surrounded at probe tip, not at the surface of the probe tip. By using this, the sheath thickness can be obtained, if we know some unknown parameters, such as ion current, plasma density, and electron temperature. In this paper, we present a method to measure sheath thickness by using a wave cutoff method and a floating harmonic method. The measured result is in a good agreement with Allen-Boyd-Reynolds theory.

  6. First Absolutely Calibrated Localized Measurements of Ion Velocity in the MST in Locked and Rotating Plasmas

    NASA Astrophysics Data System (ADS)

    Baltzer, M.; Craig, D.; den Hartog, D. J.; Nornberg, M. D.; Munaretto, S.

    2015-11-01

    An Ion Doppler Spectrometer (IDS) is used on MST for high time-resolution passive and active measurements of impurity ion emission. Absolutely calibrated measurements of flow are difficult because the spectrometer records data within 0.3 nm of the C+5 line of interest, and commercial calibration lamps do not produce lines in this narrow range . A novel optical system was designed to absolutely calibrate the IDS. The device uses an UV LED to produce a broad emission curve in the desired region. A Fabry-Perot etalon filters this light, cutting transmittance peaks into the pattern of the LED emission. An optical train of fused silica lenses focuses the light into the IDS with f/4. A holographic diffuser blurs the light cone to increase homogeneity. Using this light source, the absolute Doppler shift of ion emissions can be measured in MST plasmas. In combination with charge exchange recombination spectroscopy, localized ion velocities can now be measured. Previously, a time-averaged measurement along the chord bisecting the poloidal plane was used to calibrate the IDS; the quality of these central chord calibrations can be characterized with our absolute calibration. Calibration errors may also be quantified and minimized by optimizing the curve-fitting process. Preliminary measurements of toroidal velocity in locked and rotating plasmas will be shown. This work has been supported by the US DOE.

  7. Evaluation of UT Wall Thickness Measurements and Measurement Methodology

    SciTech Connect

    Weier, Dennis R.; Pardini, Allan F.

    2007-10-01

    CH2M HILL has requested that PNNL examine the ultrasonic methodology utilized in the inspection of the Hanford double shell waste tanks. Specifically, PNNL is to evaluate the UT process variability and capability to detect changes in wall thickness and to document the UT operator's techniques and methodology in the determination of the reported minimum and average UT data and how it compares to the raw (unanalyzed) UT data.

  8. Measurement of compressed breast thickness by optical stereoscopic photogrammetry.

    PubMed

    Tyson, Albert H; Mawdsley, Gordon E; Yaffe, Martin J

    2009-02-01

    The determination of volumetric breast density (VBD) from mammograms requires accurate knowledge of the thickness of the compressed breast. In attempting to accurately determine VBD from images obtained on conventional mammography systems, the authors found that the thickness reported by a number of mammography systems in the field varied by as much as 15 mm when compressing the same breast or phantom. In order to evaluate the behavior of mammographic compression systems and to be able to predict the thickness at different locations in the breast on patients, they have developed a method for measuring the local thickness of the breast at all points of contact with the compression paddle using optical stereoscopic photogrammetry. On both flat (solid) and compressible phantoms, the measurements were accurate to better than 1 mm with a precision of 0.2 mm. In a pilot study, this method was used to measure thickness on 108 volunteers who were undergoing mammography examination. This measurement tool will allow us to characterize paddle surface deformations, deflections and calibration offsets for mammographic units.

  9. Measurements of absolute M-subshell X-ray production cross sections of Th by electron impact

    NASA Astrophysics Data System (ADS)

    Moy, A.; Merlet, C.; Dugne, O.

    2014-08-01

    Measurements of absolute M-subshell X-ray production cross sections for element Th were made by electron impact for energies ranging from the ionization threshold up to 38 keV. Experimental data were obtained by measuring the X-ray intensity emitted from ultrathin Th films deposited onto self-supporting C backing films. The measurements were conducted with an electron microprobe using high-resolution wavelength dispersive spectrometers. Recorded intensities were converted into absolute X-ray production cross sections by means of atomic data and estimation of the number of primary electrons, target thickness, and detector efficiency. Our experimental X-ray production cross sections, the first to be reported for the M subshells of Th, are compared with X-ray production cross sections calculated with the mean of ionization cross sections obtained from the distorted-wave Born approximation. The Mα X-ray production cross section calculated is in excellent agreement with the measurements, allowing future use for standardless quantification in electron probe microanalysis.

  10. Optical in-situ monitoring system for simultaneous measurement of thickness and curvature of thick layer stacks during hydride vapor phase epitaxy growth of GaN

    NASA Astrophysics Data System (ADS)

    Semmelroth, K.; Berwian, P.; Schröter, C.; Leibiger, G.; Schönleber, M.; Friedrich, J.

    2015-10-01

    For improved real-time process control we integrated a novel optical in-situ monitoring system in a vertical reactor for hydride vapor phase epitaxy (HVPE) growth of gallium nitride (GaN) bulk crystals. The in-situ monitoring system consists of a fiber-optical interferometric sensor in combination with an optimized differential measuring head. The system only needs one small optical path perpendicular to the center of the layer stack typically consisting of sapphire as substrate and GaN. It can handle sample distances up to 1 m without difficulty. The in-situ monitoring system is simultaneously measuring the optical layer thicknesses of the GaN/sapphire layer stack and the absolute change of the distance between the measuring head and the backside of the layer stack. From this data it is possible to calculate the thickness of the growing GaN up to a thickness of about 1000 μm and the absolute change in curvature of the layer stack. The performance of the in-situ monitoring system is shown and discussed based on the measured interference signals recorded during a short-time and a long-time HVPE growth run.

  11. In-Situ Measurements of Fabric Thickness Evolution During Draping

    SciTech Connect

    Ivanov, D. S.; Van Gestel, C.; Lomov, S. V.; Verpoest, I.

    2011-05-04

    The paper presents results of experimental program aimed at measuring fabric thickening while draping. The thickness evolution is important factor in resin infusion manufacturing where the resultant composite thickness is not controlled. The measurements are conducted by means of laser distance sensors adapted to the picture frame testing. Several carbon fabrics of very different architectures have been tested. Additionally, the pretension of the carbon fabric due to the gripping has been estimated by means of digital image correlation technique and an attempt to discuss the results obtained on different set-ups is made.

  12. Anthropometric measurements as predictors of intraabdominal fat thickness.

    PubMed

    Roopakala, M S; Suresh, Anagha; Ashtalakshmi; Srinath; Ashok; Giridhar; Anand; Silvia, Wilma Delphine

    2009-01-01

    Central obesity is known to be an important risk factor in the development of metabolic syndrome and intraabdominal fat thickness has been found to be a reliable indicator of central obesity. Many anthropometric indicators have been suggested for measuring intraabdominal fat. The aim of this study was to relate various anthropometric measurements to intraabdominal fat thickness and to determine which among these is a better predictor of intra abdominal fat in normal subjects. This cross sectional study was carried out. in 60 healthy subjects (32 males and 28 females) in the age group of 25-55 years. Anthropometric measurements such as BMI, waist circumference and waist-hip ratio were assessed by using standard methods. Subcutaneous and visceral fat were measured 1 cm above umbilicus by ultrasonography. Intraabdominal fat thickness was correlated with the anthropometric measures by Pearson's test. Multivariate linear regression test was used to find the best anthropometric measurement as a predictor of abdominal fat. Waist circumference showed a significant positive correlation with subcutaneous fat and visceral fat. Waist circumference was found to be the best predictor of intraabdominal fat thickness in normal subjects and therefore of central obesity.

  13. Re-creating Gauss's method for non-electrical absolute measurements of magnetic fields and moments

    NASA Astrophysics Data System (ADS)

    Van Baak, D. A.

    2013-10-01

    In 1832, Gauss made the first absolute measurements of magnetic fields and of magnetic moments in experiments that are straightforward and instructive to replicate. We show, using rare-earth permanent magnets and a variation of Gauss's technique, that the horizontal component of the ambient geomagnetic field, as well as the size of the magnetic moments of such magnets, can be found. The method shows the connection between the SI and cgs emu unit systems for these quantities and permits an absolute realization of the Ampere with considerable precision.

  14. Absolute cross-section measurements for ionization of He Rydberg atoms in collisions with K

    NASA Astrophysics Data System (ADS)

    Deng, F.; Renwick, S.; Martínez, H.; Morgan, T. J.

    1995-11-01

    Absolute cross sections for ionization of 1.5-10.0 keV/amu Rydberg helium atoms in principal quantum states 12<=n<=15 due to collisions with potassium have been measured. The data are compared with the free-electron cross section at equal velocity. Our results for the collisional ionization cross sections (σi) agree both in shape and absolute magnitude with the data available for the total electron-scattering cross sections (σe) and support recent theoretical models for ionization of Rydberg atoms with neutral perturbers.

  15. Superharp: A wire scanner with absolute position readout for beam energy measurement at CEBAF

    SciTech Connect

    Yan, C.

    1994-09-07

    Superharp is an upgrade CEBAF wire scanner with absolute position readout from shaft encoder. As high precision absolute beam position probe ({Delta}x {approximately} 10{mu}m), three pairs of superharps are installed at the entrance, the mid-point, and the exit of Hall C arc beamline in beam switch yard, which will be tuned in dispersive mode as energy spectrometer performing 10{sup {minus}3} beam energy measurement. With dual sensor system: the direct current pickup and the bremsstrahlung detection electronics, beam profile can be obtained by superharp at wide beam current range from 1 {mu}A to 100 {mu}A.

  16. Sand Shear Band Thickness Measurements by Digital Imaging Techniques

    NASA Technical Reports Server (NTRS)

    Alshibli, Khalid A.; Sture, Stein

    1998-01-01

    Digital imaging analysis was used to study localized deformations in granular materials tested under plane strain condition. Two independent techniques were applied and compared. In the first, the digitized optical images of a grid printed on the latex membrane were used to measure the shear band orientation angle and thickness, and were found to be 54.5' and 3.01 mm respectively. The second technique involved introducing an ultra-low viscosity resin into the specimen in preparation for thin- sectioning and microscopic study of the internal fabric. A total of 24 microscopic images obtained from four thin sections were analyzed and void ratio variation was measured. The shear band thickness measurements from images located along the shear band axis (at two locations) were equal to 3.19 mm and 3.29 mm which are very close to the average value obtained from surface analysis. The study was then extended to investigate the effects of sand grain-size and properties, specimen density, and confining pressure on shear band thickness. It was found that the normalized shear band thickness decreases as grain-size and confining pressure increase and as density decreases. Finally, shear band thickness is highly influenced by the specimen dilatancy.

  17. High Accuracy, Absolute, Cryogenic Refractive Index Measurements of Infrared Lens Materials for JWST NIRCam using CHARMS

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas; Frey, Bradley

    2005-01-01

    The current refractive optical design of the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF, BaF2, and ZnSe. In order to provide the instrument s optical designers with accurate, heretofore unavailable data for absolute refractive index based on actual cryogenic measurements, two prismatic samples of each material were measured using the cryogenic, high accuracy, refraction measuring system (CHARMS) at NASA GSFC, densely covering the temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6 microns. Measurement methods are discussed and graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient for these three materials are presented along with estimates of uncertainty. Coefficients for second order polynomial fits of measured index to temperature are provided for many wavelengths to allow accurate interpolation of index to other wavelengths and temperatures.

  18. Fully distributed absolute blood flow velocity measurement for middle cerebral arteries using Doppler optical coherence tomography

    PubMed Central

    Qi, Li; Zhu, Jiang; Hancock, Aneeka M.; Dai, Cuixia; Zhang, Xuping; Frostig, Ron D.; Chen, Zhongping

    2016-01-01

    Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it is related to vessel geometry. In this paper, we present a volumetric vessel reconstruction approach that is capable of measuring the absolute BFV distributed along the entire middle cerebral artery (MCA) within a large field-of-view. The Doppler angle at each point of the MCA, representing the vessel geometry, is derived analytically by localizing the artery from pure DOCT images through vessel segmentation and skeletonization. Our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches. Experiments on rodents using swept-source optical coherence tomography showed that our approach was able to reveal the consequences of permanent MCA occlusion with absolute BFV measurement. PMID:26977365

  19. Demonstrating the Error Budget for the Climate Absolute Radiance and Refractivity Observatory Through Solar Irradiance Measurements

    NASA Technical Reports Server (NTRS)

    Thome, Kurtis; McCorkel, Joel; McAndrew, Brendan

    2016-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission addresses the need to observe highaccuracy, long-term climate change trends and to use decadal change observations as a method to determine the accuracy of climate change. A CLARREO objective is to improve the accuracy of SI-traceable, absolute calibration at infrared and reflected solar wavelengths to reach on-orbit accuracies required to allow climate change observations to survive data gaps and observe climate change at the limit of natural variability. Such an effort will also demonstrate National Institute of Standards and Technology (NIST) approaches for use in future spaceborne instruments. The current work describes the results of laboratory and field measurements with the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. SOLARIS allows testing and evaluation of calibration approaches, alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. Results of laboratory calibration measurements are provided to demonstrate key assumptions about instrument behavior that are needed to achieve CLARREO's climate measurement requirements. Absolute radiometric response is determined using laser-based calibration sources and applied to direct solar views for comparison with accepted solar irradiance models to demonstrate accuracy values giving confidence in the error budget for the CLARREO reflectance retrieval.

  20. Introducing an Absolute Cavity Pyrgeometer for Improving the Atmospheric Longwave Irradiance Measurement (Presentation)

    SciTech Connect

    Reda, I.; Hansen, L.; Zeng, J.

    2012-08-01

    Advancing climate change research requires accurate and traceable measurement of the atmospheric longwave irradiance. Current measurement capabilities are limited to an estimated uncertainty of larger than +/- 4 W/m2 using the interim World Infrared Standard Group (WISG). WISG is traceable to the Systeme international d'unites (SI) through blackbody calibrations. An Absolute Cavity Pyrgeometer (ACP) is being developed to measure absolute outdoor longwave irradiance with traceability to SI using the temperature scale (ITS-90) and the sky as the reference source, instead of a blackbody. The ACP was designed by NREL and optically characterized by the National Institute of Standards and Technology (NIST). Under clear-sky and stable conditions, the responsivity of the ACP is determined by lowering the temperature of the cavity and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The absolute atmospheric longwave irradiance is then calculated with an uncertainty of +/- 3.96 W/m2 with traceability to SI. The measured irradiance by the ACP was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the WISG. A total of 408 readings was collected over three different clear nights. The calculated irradiance measured by the ACP was 1.5 W/m2 lower than that measured by the two pyrgeometers that are traceable to WISG. Further development and characterization of the ACP might contribute to the effort of improving the uncertainty and traceability of WISG to SI.

  1. Frequency-scanning interferometry for dynamic absolute distance measurement using Kalman filter.

    PubMed

    Tao, Long; Liu, Zhigang; Zhang, Weibo; Zhou, Yangli

    2014-12-15

    We propose a frequency-scanning interferometry using the Kalman filtering technique for dynamic absolute distance measurement. Frequency-scanning interferometry only uses a single tunable laser driven by a triangle waveform signal for forward and backward optical frequency scanning. The absolute distance and moving speed of a target can be estimated by the present input measurement of frequency-scanning interferometry and the previously calculated state based on the Kalman filter algorithm. This method not only compensates for movement errors in conventional frequency-scanning interferometry, but also achieves high-precision and low-complexity dynamic measurements. Experimental results of dynamic measurements under static state, vibration and one-dimensional movement are presented.

  2. Absolute distance measurement using frequency-sweeping heterodyne interferometer calibrated by an optical frequency comb.

    PubMed

    Wu, Xuejian; Wei, Haoyun; Zhang, Hongyuan; Ren, Libing; Li, Yan; Zhang, Jitao

    2013-04-01

    We present a frequency-sweeping heterodyne interferometer to measure an absolute distance based on a frequency-tunable diode laser calibrated by an optical frequency comb (OFC) and an interferometric phase measurement system. The laser frequency-sweeping process is calibrated by the OFC within a range of 200 GHz and an accuracy of 1.3 kHz, which brings about a precise temporal synthetic wavelength of 1.499 mm. The interferometric phase measurement system consisting of the analog signal processing circuit and the digital phase meter achieves a phase difference resolution better than 0.1 deg. As the laser frequency is sweeping, the absolute distance can be determined by measuring the phase difference variation of the interference signals. In the laboratory condition, our experimental scheme realizes micrometer accuracy over meter distance.

  3. Applications of acoustics in the measurement of coal slab thickness

    NASA Technical Reports Server (NTRS)

    Hadden, W. J., Jr.; Mills, J. M.; Pierce, A. D.

    1980-01-01

    The determination of the possibility of employing acoustic waves at ultrasonic frequencies for measurements of thicknesses of slabs of coal backed by shale is investigated. Fundamental information concerning the acoustical properties of coal, and the relationship between these properties and the structural and compositional parameters used to characterize coal samples was also sought. The testing device, which utilizes two matched transducers, is described.

  4. Ultrasonic eggshell thickness measurement for selection of layers.

    PubMed

    Kibala, Lucyna; Rozempolska-Rucinska, Iwona; Kasperek, Kornel; Zieba, Grzegorz; Lukaszewicz, Marek

    2015-10-01

    This study aimed to develop a methodology for using ultrasonic technology (USG) to record eggshell thickness for selection of layers. Genetic correlations between eggshell strength and its thickness have been reported to be around 0.8, making shell thickness a selection index candidate element. Applying ultrasonic devices to measure shell thickness leaves an egg intact for further handling. In this study, eggs from 2 purebred populations of Rhode Island White (RIW) and Rhode Island Red (RIR) hens were collected on a single day in the 33rd week of the farm laying calendar from 2,414 RIR and 4,525 RIW hens. Beginning from the large end of the egg, measurements were taken at 5 latitudes: 0º (USG0), 45º (USG45), 90º (USG90), 135º (USG135), and 180º (USG180). To estimate the repeatability of readings, measurements were repeated at each parallel on 3 meridians. Electronic micrometer measurement ( EMM: ) were taken with an electronic micrometer predominantly at the wider end of eggs from 2,397 RIR and 4,447 RIW hens. A multiple-trait statistical model fit the fixed effect of year-of-hatch × hatch-within-year, and random effects due to repeated measurements (except EMM) and an animal's additive genetic component. The shell was thinnest in the region where chicks break it upon hatching (USG0, USG45). Heritabilities of shell thickness in different regions of the shell ranged from 0.09 to 0.19 (EMM) in RIW and from 0.12 to 0.23 (EMM) in RIR and were highest for USG45 and USG0. Because the measurement repeatabilities were all above 0.90, our recommendation for balancing egg strength against hatching ease is to take a single measurement of USG45. Due to high positive genetic correlations between shell thickness in different regions of the shell its thickness in the pointed end region will be modified accordingly, in response to selection for USG45.

  5. Absolute distance measurement by chirped pulse interferometry using a femtosecond pulse laser.

    PubMed

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

    2015-11-30

    We propose here a method for absolute distance measurement by chirped pulse interferometry using frequency comb. The principle is introduced, and the distance can be measured via the shift of the widest fringe. The experimental results show an agreement within 26 μm in a range up to 65 m, corresponding to a relative precision of 4 × 10-7, compared with a reference distance meter.

  6. Hilbertian sine as an absolute measure of Bayesian inference in ISR, homeland security, medicine, and defense

    NASA Astrophysics Data System (ADS)

    Jannson, Tomasz; Wang, Wenjian; Hodelin, Juan; Forrester, Thomas; Romanov, Volodymyr; Kostrzewski, Andrew

    2016-05-01

    In this paper, Bayesian Binary Sensing (BBS) is discussed as an effective tool for Bayesian Inference (BI) evaluation in interdisciplinary areas such as ISR (and, C3I), Homeland Security, QC, medicine, defense, and many others. In particular, Hilbertian Sine (HS) as an absolute measure of BI, is introduced, while avoiding relativity of decision threshold identification, as in the case of traditional measures of BI, related to false positives and false negatives.

  7. Method and apparatus for thickness measurement using microwaves

    DOEpatents

    Woskov, Paul [Bedford, MA; Lamar, David A [West Richland, WA

    2001-01-01

    The method for measuring the thickness of a material which transmits a detectable amount of microwave radiation includes irradiating the material with coherent microwave radiation tuned over a frequency range. Reflected microwave radiation is detected, the reflected radiation having maxima and minima over the frequency range as a result of coherent interference of microwaves reflected from reflecting surfaces of the material. The thickness of the material is determined from the period of the maxima and minima along with knowledge of the index of refraction of the material.

  8. Liquid film thickness measurement by two-line TDLAS

    SciTech Connect

    Yang, Huinan; Chen, Jun; Cai, Xiaoshu; Greszik, Daniel; Dreier, Thomas; Schulz, Christof

    2014-04-11

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ∼1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  9. Interferometric measurement method of thin film thickness based on FFT

    NASA Astrophysics Data System (ADS)

    Shuai, Gaolong; Su, Junhong; Yang, Lihong; Xu, Junqi

    2009-05-01

    The kernel of modern interferometry is to obtain necessary surface shape and parameter by processing interferogram with reasonable algorithm. The paper studies the basic principle of interferometry involving 2-D FFT, proposes a new method for measuring thin film thickness based on FFT: by CCD receiving and acquired card collecting with the help of Twyman-Green interferometer, can a fringe interferogram of the measured thin film be obtained. Based on the interferogram processing knowledge, an algorithm processing software/program can be prepared to realize identification of the edge films, regional extension, filtering, unwrapping the wrapped phase etc. And in this way can the distribution of film information-coated surface be obtained and the thickness of thin film samples automatically measured. The findings indicate the PV value and RMS value of the measured film samples are 0.256 λ and 0.068 λ respectively and prove the new method has high precision.

  10. Traction and film thickness measurements under starved elastohydrodynamic conditions

    NASA Technical Reports Server (NTRS)

    Wedeven, L. D.

    1974-01-01

    Traction measurements under starved elastohydrodynamic conditions were obtained for a point contact geometry. Simultaneous measurements of the film thickness and the locations of the inlet lubricant boundary were made optically. The thickness of a starved film for combination rolling and sliding conditions varies with the location of the inlet boundary in the same way found previously for pure rolling. A starved film was observed to possess greater traction than a flooded film for the same slide roll ratio. For a given slide roll ratio a starved film simply increases the shear rate in the Hertz region. The maximum shear rate depends on the degree of starvation and has no theoretical limit. Traction measurements under starved conditions were compared with flooded conditions under equivalent shear rates in the Hertz region. When the shear rates in the Hertz region were low and the film severely starved, the measured tractions were found to be much lower than expected.

  11. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature.

    PubMed

    Schmuck, S; Fessey, J; Gerbaud, T; Alper, B; Beurskens, M N A; de la Luna, E; Sirinelli, A; Zerbini, M

    2012-12-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.

  12. Absolute terahertz power measurement of a time-domain spectroscopy system.

    PubMed

    Globisch, Björn; Dietz, Roman J B; Göbel, Thorsten; Schell, Martin; Bohmeyer, Werner; Müller, Ralf; Steiger, Andreas

    2015-08-01

    We report on, to the best of our knowledge, the first absolute terahertz (THz) power measurement of a photoconductive emitter developed for time-domain spectroscopy (TDS). The broadband THz radiation emitted by a photoconductor optimized for the excitation with 1550-nm femtosecond pulses was measured by an ultrathin pyroelectric thin-film (UPTF) detector. We show that this detector has a spectrally flat transmission between 100 GHz and 5 THz due to special conductive electrodes on both sides of the UPTF. Its flat responsivity allows the calibration with a standard detector that is traceable to the International System of Units (SI) at the THz detector calibration facility of PTB. Absolute THz power in the range from below 1 μW to above 0.1 mW was measured.

  13. Determination of collagen fibril size via absolute measurements of second-harmonic generation signals.

    PubMed

    Bancelin, Stéphane; Aimé, Carole; Gusachenko, Ivan; Kowalczuk, Laura; Latour, Gaël; Coradin, Thibaud; Schanne-Klein, Marie-Claire

    2014-09-16

    The quantification of collagen fibril size is a major issue for the investigation of pathological disorders associated with structural defects of the extracellular matrix. Second-harmonic generation microscopy is a powerful technique to characterize the macromolecular organization of collagen in unstained biological tissues. Nevertheless, due to the complex coherent building of this nonlinear optical signal, it has never been used to measure fibril diameter so far. Here we report absolute measurements of second-harmonic signals from isolated fibrils down to 30 nm diameter, via implementation of correlative second-harmonic-electron microscopy. Moreover, using analytical and numerical calculations, we demonstrate that the high sensitivity of this technique originates from the parallel alignment of collagen triple helices within fibrils and the subsequent constructive interferences of second-harmonic radiations. Finally, we use these absolute measurements as a calibration for ex vivo quantification of fibril diameter in the Descemet's membrane of a diabetic rat cornea.

  14. Absolute frequency measurement at 10-16 level based on the international atomic time

    NASA Astrophysics Data System (ADS)

    Hachisu, H.; Fujieda, M.; Kumagai, M.; Ido, T.

    2016-06-01

    Referring to International Atomic Time (TAI), we measured the absolute frequency of the 87Sr lattice clock with its uncertainty of 1.1 x 10-15. Unless an optical clock is continuously operated for the five days of the TAI grid, it is required to evaluate dead time uncertainty in order to use the available five-day average of the local frequency reference. We homogeneously distributed intermittent measurements over the five-day grid of TAI, by which the dead time uncertainty was reduced to low 10-16 level. Three campaigns of the five (or four)-day consecutive measurements have resulted in the absolute frequency of the 87Sr clock transition of 429 228 004 229 872.85 (47) Hz, where the systematic uncertainty of the 87Sr optical frequency standard amounts to 8.6 x 10-17.

  15. A novel absolute measurement for the low-frequency figure correction of aspheric surfaces

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Cheng; Chang, Shenq-Tsong; Ho, Cheng-Fang; Kuo, Ching-Hsiang; Chung, Chien-Kai; Hsu, Wei-Yao; Tseng, Shih-Feng; Sung, Cheng-Kuo

    2015-07-01

    This study proposes an absolute measurement method with a computer-generated hologram (CGHs) to assist the identification of manufacturing form error, and gravity and mounting resulted distortions for a 300 mm aspherical mirror. This method adopts the frequency of peaks and valleys of each Zernike coefficient grabbed by the measurement with various orientations of the mirror in horizontal optical-axis configuration. In addition, the rotational-symmetric aberration (spherical aberration) is calibrated with random ball test method. According to the measured absolute surface figure, a high accuracy aspherical surface with peak to valley (P-V) value of 1/8 wave @ 632.8 nm was fabricated after surface figure correction with the reconstructed error map.

  16. Determination of collagen fibril size via absolute measurements of second-harmonic generation signals

    NASA Astrophysics Data System (ADS)

    Bancelin, Stéphane; Aimé, Carole; Gusachenko, Ivan; Kowalczuk, Laura; Latour, Gaël; Coradin, Thibaud; Schanne-Klein, Marie-Claire

    2014-09-01

    The quantification of collagen fibril size is a major issue for the investigation of pathological disorders associated with structural defects of the extracellular matrix. Second-harmonic generation microscopy is a powerful technique to characterize the macromolecular organization of collagen in unstained biological tissues. Nevertheless, due to the complex coherent building of this nonlinear optical signal, it has never been used to measure fibril diameter so far. Here we report absolute measurements of second-harmonic signals from isolated fibrils down to 30 nm diameter, via implementation of correlative second-harmonic-electron microscopy. Moreover, using analytical and numerical calculations, we demonstrate that the high sensitivity of this technique originates from the parallel alignment of collagen triple helices within fibrils and the subsequent constructive interferences of second-harmonic radiations. Finally, we use these absolute measurements as a calibration for ex vivo quantification of fibril diameter in the Descemet’s membrane of a diabetic rat cornea.

  17. Measuring the absolute DT neutron yield using the Magnetic Recoil Spectrometer at OMEGA and the NIF

    SciTech Connect

    Mackinnon, A; Casey, D; Frenje, J A; Johnson, M G; Seguin, F H; Li, C K; Petrasso, R D; Glebov, V Y; Katz, J; Knauer, J; Meyerhofer, D; Sangster, T; Bionta, R; Bleuel, D; Hachett, S P; Hartouni, E; Lepape, S; Mckernan, M; Moran, M; Yeamans, C

    2012-05-03

    A Magnetic Recoil Spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion (ICF) implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

  18. Sensitive and absolute absorption measurements in optical materials and coatings by laser-induced deflection technique

    NASA Astrophysics Data System (ADS)

    Mühlig, Christian; Bublitz, Simon

    2012-12-01

    The laser-induced deflection (LID) technique, a photo-thermal deflection setup with transversal pump-probe-beam arrangement, is applied for sensitive and absolute absorption measurements of optical materials and coatings. Different LID concepts for bulk and transparent coating absorption measurements, respectively, are explained, focusing on providing accurate absorption data with only one measurement and one sample. Furthermore, a new sandwich concept is introduced that allows transferring the LID technique to very small sample geometries and to significantly increase the sensitivity for materials with weak photo-thermal responses. For each of the different concepts, a representative application example is given. Particular emphasis is placed on the importance of the calibration procedure for providing absolute absorption data. The validity of an electrical calibration procedure for the LID setup is proven using specially engineered surface absorbing samples. The electrical calibration procedure is then applied to evaluate two other approaches that use either doped samples or highly absorptive reference samples.

  19. Machine vision technique for measuring glass container thickness

    NASA Astrophysics Data System (ADS)

    Ford, Ralph M.; Mercier, Jeffrey A.

    2003-05-01

    The inspection of sidewall thickness provides important information about the production processes for glass container manufacture. By monitoring the thickness profile around the perimeter of bottles in real-time, the manufacturing process can be altered to produce higher quality products. This also provides the ability to identify and remove defective products. In order to improve the speed and accuracy of inspections, a new non-contact method for acquiring thickness profiles of glass bottles that employs optical and machine vision techniques has been developed and tested. One of the fundamental laws of optics, Snell's Law, is the basic concept upon which the inspection technique relies. The thickness of a flat plane of transparent material can be determined from Snell"s Law with a single beam of light that passes through the medium, reflects off the secondary surface, and travels back to the initial surface and passes through it. Based upon this principle, a new non-contact glass thickness measurement technique has been developed and it has demonstrated good accuracy.

  20. Subnanometer absolute displacement measurement using a frequency comb referenced dual resonance tracking Fabry-Perot interferometer.

    PubMed

    Zhu, Minhao; Wei, Haoyun; Zhao, Shijie; Wu, Xuejian; Li, Yan

    2015-05-10

    Fabry-Perot (F-P) interferometry is a traceable high-resolution method for displacement metrology that has no nonlinearity. Compared with the single resonance tracking F-P interferometry, the dual resonance tracking (DRT) F-P interferometer system is able to realize tens of millimeters measurement range while maintaining the intrinsic high resolution. A DRT F-P system is thus developed for absolute displacement measurement in metrology applications. Two external cavity diode lasers (ECDLs) are simultaneously locked to two resonances of a high-finesse F-P cavity using the Pound-Drever-Hall locking scheme. The absolute optical frequencies of the locked ECDLs are measured using a reference diode laser, with the frequency stabilized and controlled by an optical frequency comb. The absolute cavity resonance order numbers are investigated. The measurement range is experimentally tested to achieve 20 mm, while the resolution reaches ~10 pm level, mainly limited by the mechanical stability of the F-P cavity. Compared with the measurement results from a self-developed displacement-angle heterodyne interferometer, the displacement residuals are within 10 nm in the range of 20 mm. This high-resolution interferometer may become a candidate for length metrology such as in Watt balance or Joule balance projects.

  1. Thorough subcells diagnosis in a multi-junction solar cell via absolute electroluminescence-efficiency measurements

    PubMed Central

    Chen, Shaoqiang; Zhu, Lin; Yoshita, Masahiro; Mochizuki, Toshimitsu; Kim, Changsu; Akiyama, Hidefumi; Imaizumi, Mitsuru; Kanemitsu, Yoshihiko

    2015-01-01

    World-wide studies on multi-junction (tandem) solar cells have led to record-breaking improvements in conversion efficiencies year after year. To obtain detailed and proper feedback for solar-cell design and fabrication, it is necessary to establish standard methods for diagnosing subcells in fabricated tandem devices. Here, we propose a potential standard method to quantify the detailed subcell properties of multi-junction solar cells based on absolute measurements of electroluminescence (EL) external quantum efficiency in addition to the conventional solar-cell external-quantum-efficiency measurements. We demonstrate that the absolute-EL-quantum-efficiency measurements provide I–V relations of individual subcells without the need for referencing measured I–V data, which is in stark contrast to previous works. Moreover, our measurements quantify the absolute rates of junction loss, non-radiative loss, radiative loss, and luminescence coupling in the subcells, which constitute the “balance sheets” of tandem solar cells. PMID:25592484

  2. Introducing an Absolute Cavity Pyrgeometer (ACP) for Improving the Atmospheric Longwave Irradiance Measurement (Poster)

    SciTech Connect

    Reda, I.; Stoffel, T.

    2012-03-01

    Advancing climate change research requires accurate and traceable measurement of the atmospheric longwave irradiance. Current measurement capabilities are limited to an estimated uncertainty of larger than +/- 4 W/m2 using the interim World Infrared Standard Group (WISG). WISG is traceable to the Systeme international d'unites (SI) through blackbody calibrations. An Absolute Cavity Pyrgeometer (ACP) is being developed to measure absolute outdoor longwave irradiance with traceability to SI using the temperature scale (ITS-90) and the sky as the reference source, instead of a blackbody. The ACP was designed by NREL and optically characterized by the National Institute of Standards and Technology (NIST). Under clear-sky and stable conditions, the responsivity of the ACP is determined by lowering the temperature of the cavity and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The absolute atmospheric longwave irradiance is then calculated with an uncertainty of +/- 3.96 W/m2 with traceability to SI. The measured irradiance by the ACP was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the WISG.

  3. Temperature-dependent Absolute Refractive Index Measurements of Synthetic Fused Silica

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.; Frey, Bradley J.

    2006-01-01

    Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, we have measured the absolute refractive index of five specimens taken from a very large boule of Corning 7980 fused silica from temperatures ranging from 30 to 310 K at wavelengths from 0.4 to 2.6 microns with an absolute uncertainty of plus or minus 1 x 10 (exp -5). Statistical variations in derived values of the thermo-optic coefficient (dn/dT) are at the plus or minus 2 x 10 (exp -8)/K level. Graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient are presented for selected wavelengths and temperatures along with estimates of uncertainty in index. Coefficients for temperature-dependent Sellmeier fits of measured refractive index are also presented to allow accurate interpolation of index to other wavelengths and temperatures. We compare our results to those from an independent investigation (which used an interferometric technique for measuring index changes as a function of temperature) whose samples were prepared from the same slugs of material from which our prisms were prepared in support of the Kepler mission. We also compare our results with sparse cryogenic index data from measurements of this material from the literature.

  4. System for absolute measurement of electrolytic conductivity in aqueous solutions based on van der Pauw's theory

    NASA Astrophysics Data System (ADS)

    Zhang, Bing; Lin, Zhen; Zhang, Xiao; Yu, Xiang; Wei, Jiali; Wang, Xiaoping

    2014-05-01

    Based on an innovative application of van der Pauw's theory, a system was developed for the absolute measurement of electrolytic conductivity in aqueous solutions. An electrolytic conductivity meter was designed that uses a four-electrode system with an axial-radial two-dimensional adjustment structure coupled to an ac voltage excitation source and signal collecting circuit. The measurement accuracy, resolution and repeatability of the measurement system were examined through a series of experiments. Moreover, the measurement system and a high-precision electrolytic conductivity meter were compared using some actual water samples.

  5. Laser induced deflection technique for absolute thin film absorption measurement: optimized concepts and experimental results

    SciTech Connect

    Muehlig, Christian; Kufert, Siegfried; Bublitz, Simon; Speck, Uwe

    2011-03-20

    Using experimental results and numerical simulations, two measuring concepts of the laser induced deflection (LID) technique are introduced and optimized for absolute thin film absorption measurements from deep ultraviolet to IR wavelengths. For transparent optical coatings, a particular probe beam deflection direction allows the absorption measurement with virtually no influence of the substrate absorption, yielding improved accuracy compared to the common techniques of separating bulk and coating absorption. For high-reflection coatings, where substrate absorption contributions are negligible, a different probe beam deflection is chosen to achieve a better signal-to-noise ratio. Various experimental results for the two different measurement concepts are presented.

  6. A novel absolute displacement measurement technology based on wavenumber resolved low coherence interferometry

    NASA Astrophysics Data System (ADS)

    Zhao, Keqiang; Xie, Fang; Ma, Sen; Wang, Yunzhi; Chen, Liang

    2015-12-01

    This paper proposed a novel absolute displacement measurement technology which is based on the wavenumber spectrum of low coherence interferometry. The signal from a Michelson interferometer, which is derived from a broadband light source, is dispersed by a bulk dispersing grating. The interferometric signal of each wavelength is detected by a linear array charge coupled device (CCD). By transforming the wavelength spectrum of the signal into wavenumber spectrum, absolute displacement can be measured precisely by measuring the wavenumber difference between two neighboring peaks of the wavenumber spectrum. Unlike the normal low coherence interferometric measurement systems (LCIMS) which have to scan the optical path difference (OPD) of the interferometer in order to demodulate the measurand, there is no need of scanning action during the measurement procedure, which not only simplifies the measurement system but also improves the measurement speed greatly. A fiber Bragg grating (FBG) is employed to produce a feedback signal which is used to stabilize the Michelson interferometer so as to obtain high measurement precision. A step height with the calibrated value of 50 μm that is configurated with two gauge blocks is measured by the system. The measurement resolution is 6.03 nm and the standard deviation of 10 times measurement results is 6.8 nm.

  7. High-accuracy absolute distance measurement with a mode-resolved optical frequency comb

    NASA Astrophysics Data System (ADS)

    Voigt, Dirk; van den Berg, Steven A.; Lešundák, Adam; van Eldik, Sjoerd; Bhattacharya, Nandini

    2016-04-01

    Optical interferometry enables highly accurate non-contact displacement measurement. The optical phase ambiguity needs to be resolved for absolute distance ranging. In controlled laboratory conditions and for short distances it is possible to track a non-interrupted displacement from a reference position to a remote target. With large distances covered in field applications this may not be feasible, e.g. in structure monitoring, large scale industrial manufacturing or aerospace navigation and attitude control. We use an optical frequency comb source to explore absolute distance measurement by means of a combined spectral and multi-wavelength homodyne interferometry. This relaxes the absolute distance ambiguity to a few tens of centimeters, covered by simpler electronic distance meters, while maintaining highly accurate optical phase measuring capability. A virtually imaged phased array spectrometer records a spatially dispersed interferogram in a single exposure and allows for resolving the modes of our near infrared comb source with 1 GHz mode separation. This enables measurements with direct traceability of the atomic clock referenced comb source. We observed agreement within 500 nm in comparison with a commercial displacement interferometer for target distances up to 50 m. Furthermore, we report on current work toward applicability in less controlled conditions. A filter cavity decimates the comb source to an increased mode separation larger than 20 GHz. A simple grating spectrometer then allows to record mode-resolved interferograms.

  8. Absolute distance measurement by dual-comb nonlinear asynchronous optical sampling.

    PubMed

    Zhang, Hongyuan; Wei, Haoyun; Wu, Xuejian; Yang, Honglei; Li, Yan

    2014-03-24

    A dual-comb nonlinear asynchronous optical sampling method is proposed to simplify determination of the time interval and extend the non-ambiguity range in absolute length measurements. Type II second harmonic generation facilitates curve fitting in determining the time interval between adjacent pulses. Meanwhile, the non-ambiguity range is extended by adjusting the repetition rate of the signal laser. The performance of the proposed method is compared with a heterodyne interferometer. Results show that the system achieves a maximum residual of 100.6 nm and an uncertainty of 1.48 μm in a 0.5 ms acquisition time. With longer acquisition time, the uncertainty can be reduced to 166.6 nm for 50 ms and 82.9 nm for 500 ms. Moreover, the extension of the non-ambiguity range is demonstrated by measuring an absolute distance beyond the inherent range determined by the fixed repetition rate.

  9. Absolute frequency measurement of rubidium 5S-7S two-photon transitions.

    PubMed

    Morzyński, Piotr; Wcisło, Piotr; Ablewski, Piotr; Gartman, Rafał; Gawlik, Wojciech; Masłowski, Piotr; Nagórny, Bartłomiej; Ozimek, Filip; Radzewicz, Czesław; Witkowski, Marcin; Ciuryło, Roman; Zawada, Michał

    2013-11-15

    We report the absolute frequency measurements of rubidium 5S-7S two-photon transitions with a cw laser digitally locked to an atomic transition and referenced to an optical frequency comb. The narrow, two-photon transition, 5S-7S (760 nm), insensitive to first-order in a magnetic field, is a promising candidate for frequency reference. The performed tests yielded more accurate transition frequencies than previously reported.

  10. Development of explicit diffraction corrections for absolute measurements of acoustic nonlinearity parameters in the quasilinear regime.

    PubMed

    Jeong, Hyunjo; Zhang, Shuzeng; Cho, Sungjong; Li, Xiongbing

    2016-08-01

    In absolute measurements of acoustic nonlinearity parameters, amplitudes of harmonics must be corrected for diffraction effects. In this study, we develop explicit multi-Gaussian beam (MGB) model-based diffraction corrections for the first three harmonics in weakly nonlinear, axisymmetric sound beams. The effects of making diffraction corrections on nonlinearity parameter estimation are investigated by defining "total diffraction correction (TDC)". The results demonstrate that TDC cannot be neglected even for harmonic generation experiments in the nearfield region.

  11. Measurement of absolute displacement by a double-modulation technique based on a Michelson interferometer.

    PubMed

    Chang, L W; Chien, P Y; Lee, C T

    1999-05-01

    A novel method is presented for of measuring absolute displacement with a synthesized wavelength interferometer. The optical phase of the interferometer is simultaneously modulated with a frequency-modulated laser diode and optical path-length difference. The error signal originating from the intensity modulation of the source is eliminated by a signal processing circuit. In addition, a lock-in technique is used to demodulate the envelope of the interferometric signal. The displacement signal is derived by the self-mixing technique.

  12. A new absolute reference for atmospheric longwave irradiance measurements with traceability to SI units

    NASA Astrophysics Data System (ADS)

    Gröbner, J.; Reda, I.; Wacker, S.; Nyeki, S.; Behrens, K.; Gorman, J.

    2014-06-01

    Two independently designed and calibrated absolute radiometers measuring downwelling longwave irradiance were compared during two field campaigns in February and October 2013 at Physikalisch Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC). One absolute cavity pyrgeometer (ACP) developed by NREL and up to four Integrating Sphere Infrared Radiometers (IRIS) developed by PMOD/WRC took part in these intercomparisons. The internal consistency of the IRIS radiometers and the agreement with the ACP were within ±1 W m-2, providing traceability of atmospheric longwave irradiance to the international system of units with unprecedented accuracy. Measurements performed during the two field campaigns and over the past 4 years have shown that the World Infrared Standard Group (WISG) of pyrgeometers is underestimating clear-sky atmospheric longwave irradiance by 2 to 6 W m-2, depending on the amount of integrated water vapor (IWV). This behavior is an instrument-dependent feature and requires an individual sensitivity calibration of each pyrgeometer with respect to an absolute reference such as IRIS or ACP. For IWV larger than 10 mm, an average sensitivity correction of +6.5% should be applied to the WISG in order to be consistent with the longwave reference represented by the ACP and IRIS radiometers. A concerted effort at international level will need to be implemented in order to correct measurements of atmospheric downwelling longwave irradiance traceable to the WISG.

  13. Sounding rocket measurement of the absolute solar EUV flux utilizing a silicon photodiode

    SciTech Connect

    Ogawa, H.S.; McMullin, D.; Judge, D.L. ); Canfield, L.R. )

    1990-04-01

    A newly developed stable and high quantum efficiency silicon photodiode was used to obtain an accurate measurement of the integrated absolute magnitude of the solar extreme ultraviolet photon flux in the spectral region between 50 and 800 {angstrom}. The detector was flown aboard a solar point sounding rocket launched from White Sands Missile Range in New Mexico on October 24, 1988. The adjusted daily 10.7-cm solar radio flux and sunspot number were 168.4 and 121, respectively. The unattenuated absolute value of the solar EUV flux at 1 AU in the specified wavelength region was 6.81 {times} 10{sup 10} photons cm{sup {minus}2} s{sup {minus}1}. Based on a nominal probable error of 7% for National Institute of Standards and Technology detector efficiency measurements in the 50- to 500-{angstrom} region (5% on longer wavelength measurements between 500 and 1216 {angstrom}), and based on experimental errors associated with their rocket instrumentation and analysis, a conservative total error estimate of {approximately}14% is assigned to the absolute integral solar flux obtained.

  14. Absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer.

    PubMed

    Hirano, Masahiro; Katoh, Munenori

    2015-07-01

    [Purpose] The aim of this study was to verify the absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD). [Subjects and Methods] The subjects were 33 healthy college students. The measurements were made three times with the HHD fixed using a belt (BFHHD) or with the examiner's hand (conventional method; HFHHD). The absolute reliability of measurements was verified using Bland-Altman analysis, both in the all subjects group and a group of subjects showing measurements less than a fixed limit of 30 kgf. [Results] In the <30 kgf group, a systematic bias was not observed, and BFHHD values were greater than HFHHD values. BFHHD values in the all subjects group showed a systematic bias; the 3rd measurement value was less than the maximum value obtained during the 1st and 2nd measurements. [Conclusion] For obtaining an acceptable value during clinical measurements of horizontal adductor muscle strength, single measurements obtained using an HFHHD in the case of a <30 kgf group and the maximum value of two measurements obtained using a BFHHD are reliable.

  15. A New Measurement of the Absolute Spectral Reflectance of the Moon

    NASA Technical Reports Server (NTRS)

    Lawrence, S. J.; Lau, E.; Steutel, D.; Stopar, J. D.; Wilcox, B. B.; Lucey, P. G.

    2003-01-01

    The spectral reflectance of the Moon is an important property for studies of lunar geology, quantitative physical modeling of the moon, and in-flight calibration of spacecraft sensors. Previous studies have claimed that telescopic absolute reflectance values for the Moon are greater than laboratory reflectance measurements by a factor of two. In order to confirm these results, we performed ground-based observations of the lunar surface using a visible/near-infrared spectroradiometer and compared the measured lunar surface radiance to solar radiance corrected for atmospheric scattering and absorption. These data were compared to previously obtained laboratory reflectance measurements from Apollo soil samples.

  16. Position error correction in absolute surface measurement based on a multi-angle averaging method

    NASA Astrophysics Data System (ADS)

    Wang, Weibo; Wu, Biwei; Liu, Pengfei; Liu, Jian; Tan, Jiubin

    2017-04-01

    We present a method for position error correction in absolute surface measurement based on a multi-angle averaging method. Differences in shear rotation measurements at overlapping areas can be used to estimate the unknown relative position errors of the measurements. The model and the solving of the estimation algorithm have been discussed in detail. The estimation algorithm adopts a least-squares technique to eliminate azimuthal errors caused by rotation inaccuracy. The cost functions can be minimized to determine the true values of the unknowns of Zernike polynomial coefficients and rotation angle. Experimental results show the validity of the method proposed.

  17. Measurement of the lithium 10p fine structure interval and absolute energy

    SciTech Connect

    Oxley, Paul; Collins, Patrick

    2010-02-15

    We report a measurement of the fine structure interval of the {sup 7}Li 10p atomic state with a precision significantly better than previous measurements of fine structure intervals of Rydberg {sup 7}Li p states. Our result of 74.97(74) MHz provides an experimental value for the only n=10 fine structure interval which is yet to be calculated. We also report a measurement of the absolute energy of the 10p state and its quantum defect, which are, respectively, 42379.498(23)cm{sup -1} and 0.04694(10). These results are in good agreement with recent calculations.

  18. Absolute Measurement of Electron Cloud Density in aPositively-Charged Particle Beam

    SciTech Connect

    Kireeff Covo, Michel; Molvik, Arthur W.; Friedman, Alex; Vay,Jean-Luc; Seidl, Peter A.; Logan, Grant; Baca, David; Vujic, Jasmina L.

    2006-04-27

    Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron cloud density during the beam pulse.

  19. Absolute Measurement of Electron Cloud Density in a Positively-Charged Particle Beam

    SciTech Connect

    Covo, M K; Molvik, A W; Friedman, A; Vay, J; Seidl, P A; Logan, B G; Baca, D; Vujic, J L

    2006-05-18

    Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron cloud density during the beam pulse.

  20. Absolute measurement of electron-cloud density in a positively charged particle beam.

    PubMed

    Kireeff Covo, Michel; Molvik, Arthur W; Friedman, Alex; Vay, Jean-Luc; Seidl, Peter A; Logan, Grant; Baca, David; Vujic, Jasmina L

    2006-08-04

    Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron-cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron-cloud density during the beam pulse.

  1. Early detection of AD using cortical thickness measurements

    NASA Astrophysics Data System (ADS)

    Spjuth, M.; Gravesen, F.; Eskildsen, S. F.; Østergaard, L. R.

    2007-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder that causes cortical atrophy and impaired cognitive functions. The diagnosis is difficult to make and is often made over a longer period of time using a combination of neuropsychological tests, and structural and functional imaging. Due to the impact of early intervention the challenge of distinguishing early AD from normal ageing has received increasing attention. This study uses cortical thickness measurements to characterize the atrophy in nine mild AD patients (mean MMSE-score 23.3 (std: 2.6)) compared to five healthy middle-aged subjects. A fully automated method based on deformable models is used for delineation of the inner and outer boundaries of the cerebral cortex from Magnetic Resonance Images. This allows observer independent high-resolution quantification of the cortical thickness. The cortex analysis facilitates detection of alterations throughout the entire cortical mantle. To perform inter-subject thickness comparison in which the spatial information is retained, a feature-based registration algorithm is developed which uses local cortical curvature, normal vector, and a distance measure. A comparison of the two study groups reveals that the lateral side of the hemispheres shows diffuse thinner areas in the mild AD group but especially the medial side shows a pronounced thinner area which can be explained by early limbic changes in AD. For classification principal component analysis is applied to reduce the high number of thickness measurements (>200,000) into fewer features. All mild AD and healthy middle-aged subjects are classified correctly (sensitivity and specificity 100%).

  2. Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source.

    PubMed

    Tiedtke, K; Sorokin, A A; Jastrow, U; Juranić, P; Kreis, S; Gerken, N; Richter, M; Arp, U; Feng, Y; Nordlund, D; Soufli, R; Fernández-Perea, M; Juha, L; Heimann, P; Nagler, B; Lee, H J; Mack, S; Cammarata, M; Krupin, O; Messerschmidt, M; Holmes, M; Rowen, M; Schlotter, W; Moeller, S; Turner, J J

    2014-09-08

    This paper reports novel measurements of x-ray optical radiation on an absolute scale from the intense and ultra-short radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the detection principle for radiation measurements which was specifically adapted for this photon energy range. We present data characterizing the soft x-ray instrument at the Linac Coherent Light Source (LCLS) with respect to the radiant power output and transmission by using an absolute detector temporarily placed at the downstream end of the instrument. This provides an estimation of the reflectivity of all x-ray optical elements in the beamline and provides the absolute photon number per bandwidth per pulse. This parameter is important for many experiments that need to understand the trade-offs between high energy resolution and high flux, such as experiments focused on studying materials via resonant processes. Furthermore, the results are compared with the LCLS diagnostic gas detectors to test the limits of linearity, and observations are reported on radiation contamination from spontaneous undulator radiation and higher harmonic content.

  3. Developing absolute shock wave equation of state measurements on the NIF

    NASA Astrophysics Data System (ADS)

    Celliers, Peter; Fratanduono, D. E.; Lazicki, A.; London, R. A.; Brygoo, S.; Swift, D. C.; Coppari, F.; Millot, M.; Peterson, J. L.; Meezan, N. B.; Fernandez-Panella, A.; Erskine, D. J.; Ali, S.; Collins, G. W.

    2016-10-01

    The National Ignition Facility provides an unprecedented capability to generate ultra-high pressure planar shock waves (around 10 TPa) in solid samples. We are currently fielding impedance match equation of state (EOS) experiments to determine the shock Hugoniot of various samples relative to EOS standards, such as aluminum and quartz. However, the equations of state of the standards at multi-TPa shock pressures are not yet well-established. Absolute techniques are needed to provide the data needed to establish the Hugoniots of the standards, and also to measure the state of a sample directly. We are pursuing several approaches using absolute techniques. These approaches will be discussed. This work was performed under the auspices of the U.S. Department of Energy by LLNL under contract DE-AC52-07NA27344.

  4. Measurements of absolute concentrations of NADH in cells using the phasor FLIM method.

    PubMed

    Ma, Ning; Digman, Michelle A; Malacrida, Leonel; Gratton, Enrico

    2016-07-01

    We propose a graphical method using the phasor representation of the fluorescence decay to derive the absolute concentration of NADH in cells. The method requires the measurement of a solution of NADH at a known concentration. The phasor representation of the fluorescence decay accounts for the differences in quantum yield of the free and bound form of NADH, pixel by pixel of an image. The concentration of NADH in every pixel in a cell is obtained after adding to each pixel in the phasor plot a given amount of unmodulated light which causes a shift of the phasor towards the origin by an amount that depends on the intensity at the pixel and the fluorescence lifetime at the pixel. The absolute concentration of NADH is obtained by comparison of the shift obtained at each pixel of an image with the shift of the calibrated solution.

  5. Measurements of absolute concentrations of NADH in cells using the phasor FLIM method

    PubMed Central

    Ma, Ning; Digman, Michelle A.; Malacrida, Leonel; Gratton, Enrico

    2016-01-01

    We propose a graphical method using the phasor representation of the fluorescence decay to derive the absolute concentration of NADH in cells. The method requires the measurement of a solution of NADH at a known concentration. The phasor representation of the fluorescence decay accounts for the differences in quantum yield of the free and bound form of NADH, pixel by pixel of an image. The concentration of NADH in every pixel in a cell is obtained after adding to each pixel in the phasor plot a given amount of unmodulated light which causes a shift of the phasor towards the origin by an amount that depends on the intensity at the pixel and the fluorescence lifetime at the pixel. The absolute concentration of NADH is obtained by comparison of the shift obtained at each pixel of an image with the shift of the calibrated solution. PMID:27446681

  6. Absolute sensitivity calibration of an extreme ultraviolet spectrometer for tokamak measurements

    NASA Astrophysics Data System (ADS)

    Guirlet, R.; Schwob, J. L.; Meyer, O.; Vartanian, S.

    2017-01-01

    An extreme ultraviolet spectrometer installed on the Tore Supra tokamak has been calibrated in absolute units of brightness in the range 10-340 Å. This has been performed by means of a combination of techniques. The range 10-113 Å was absolutely calibrated by using an ultrasoft-X ray source emitting six spectral lines in this range. The calibration transfer to the range 113-182 Å was performed using the spectral line intensity branching ratio method. The range 182-340 Å was calibrated thanks to radiative-collisional modelling of spectral line intensity ratios. The maximum sensitivity of the spectrometer was found to lie around 100 Å. Around this wavelength, the sensitivity is fairly flat in a 80 Å wide interval. The spatial variations of sensitivity along the detector assembly were also measured. The observed trend is related to the quantum efficiency decrease as the angle of the incoming photon trajectories becomes more grazing.

  7. Mammographic calcification cluster detection and threshold gold thickness measurements

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Mackenzie, A.; Cooke, J.; Given-Wilson, R.; Wallis, M. G.; Chakraborty, D. P.; Dance, D. R.; Young, K. C.

    2012-03-01

    European Guidelines for quality control in digital mammography specify acceptable and achievable standards of image quality (IQ) in terms of threshold gold thickness using the CDMAM test object. However, there is little evidence relating such measurements to cancer detection. This work investigated the relationship between calcification detection and threshold gold thickness. An observer study was performed using a set of 162 amorphous selenium direct digital (DR) detector images (81 no cancer and 81 with 1-3 inserted calcification clusters). From these images four additional IQs were simulated: different digital detectors (computed radiography (CR) and DR) and dose levels. Seven observers marked and rated the locations of suspicious regions. DBM analysis of variances was performed on the JAFROC figure of merit (FoM) yielding 95% confidence intervals for IQ pairs. Automated threshold gold thickness (Tg) analysis was performed for the 0.25mm gold disc diameter on CDMAM images at the same IQs (16 images per IQ). Tg was plotted against FoM and a power law fitted to the data. There was a significant reduction in FoM for calcification detection for CR images compared with DR; FoM decreased from 0.83 to 0.63 (p<=0.0001). Detection was also sensitive to dose. There was a good correlation between FoM and Tg (R2=0.80, p<0.05), consequently threshold gold thickness was a good predictor of calcification detection at the same IQ. Since the majority of threshold gold thicknesses for the various IQs were above the acceptable standard despite large variations in calcification detection by radiologists, current EU guidelines may need revising.

  8. Absolute silicon molar mass measurements, the Avogadro constant and the redefinition of the kilogram

    NASA Astrophysics Data System (ADS)

    Vocke, R. D., Jr.; Rabb, S. A.; Turk, G. C.

    2014-10-01

    The results of an absolute silicon molar mass determination of two independent sets of samples from the highly 28Si-enriched crystal (AVO28) produced by the International Avogadro Coordination are presented and compared with results published by the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Research Council (NRC, Canada) and the National Metrology Institute of Japan (NMIJ, Japan). This study developed and describes significant changes to the published protocols for producing absolute silicon isotope ratios. The measurements were made at very high resolution on a multi-collector inductively coupled plasma mass spectrometer using tetramethylammonium hydroxide (TMAH) to dissolve and dilute all samples. The various changes in the measurement protocol and the use of TMAH resulted in significant improvements to the silicon isotope ratio precision over previously reported measurements and in particular, the robustness of the 29Si/30Si ratio of the AVO28 material. These new results suggest that a limited isotopic variability is present in the AVO28 material. The presence of this variability is at present singular and therefore its significance is not well understood. Fortunately, its magnitude is small enough so as to have an insignificant effect on the overall uncertainty of an Avogadro constant derived from the average molar mass of all four AVO28 silicon samples measured in this study. The NIST results confirm the AVO28 molar mass values reported by PTB and NMIJ and confirm that the virtual element-isotope dilution mass spectrometry approach to calibrated absolute isotope ratio measurements developed by PTB is capable of very high precision as well as accuracy. The Avogadro constant NA and derived Planck constant h based on these measurements, together with their associated standard uncertainties, are 6.02214076(19) × 1023 mol-1 and 6.62607017(21) × 10-34 Js, respectively.

  9. Absolute X-ray emission cross section measurements of Fe K transitions

    NASA Astrophysics Data System (ADS)

    Hell, Natalie; Brown, Gregory V.; Beiersdorfer, Peter; Boyce, Kevin R.; Grinberg, Victoria; Kelley, Richard L.; Kilbourne, Caroline; Leutenegger, Maurice A.; Porter, Frederick Scott; Wilms, Jörn

    2016-06-01

    We have measured the absolute X-ray emission cross sections of K-shell transitions in highly charged L- and K-shell Fe ions using the LLNL EBIT-I electron beam ion trap and the NASA GSFC EBIT Calorimeter Spectrometer (ECS). The cross sections are determined by using the ECS to simultaneously record the spectrum of the bound-bound K-shell transitions and the emission from radiative recombination from trapped Fe ions. The measured spectrum is then brought to an absolute scale by normalizing the measured flux in the radiative recombination features to their theoretical cross sections, which are well known. Once the spectrum is brought to an absolute scale, the cross sections of the K-shell transitions are determined. These measurements are made possible by the ECS, which consists of a 32 channel array, with 14 channels optimized for detecting high energy photons (hν > 10 keV) and 18 channels optimized for detecting low energy photons (hν < 10 keV). The ECS has a large collection area, relatively high energy resolution, and a large bandpass; all properties necessary for this measurement technique to be successful. These data will be used to benchmark cross sections in the atomic reference data bases underlying the plasma modeling codes used to analyze astrophysical spectra, especially those measured by the Soft X-ray Spectrometer calorimeter instrument recently launched on the Hitomi X-ray Observatory.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and supported by NASA grants to LLNL and NASA/GSFC and by ESA under contract No. 4000114313/15/NL/CB.

  10. Impact of Spatial Aliasing on Sea-ice Thickness Measurements

    NASA Astrophysics Data System (ADS)

    Mueller, H. R.; Geiger, C. A.; Samluk, J. P.; Bernstein, E. R.; Richter-Menge, J.

    2015-12-01

    A frequency distribution of snow and sea ice is generated by counting and then binning the number of thicknesses into contiguous intervals (typically in 10 cm bins). Because sea ice is only meters thick but spans thousands of kilometers, these distributions serve as a "Rosetta Stone" to communicate proportions of thickness across scales - especially for characterizing deformation processes. Because the frequency distribution is such an important communication tool, we explore the impact of spatial aliasing on non-Gaussian distributions of snow and sea ice thickness. Using a heuristic model and >1000 in situ measurements, we show how different instrument footprint sizes and shapes can cluster thickness distributions into artificial modes, thereby distorting frequency distributions and making it difficult to compare and communicate information across spatial scales. This problem has not been dealt with systematically for sea ice until now, largely because it appears to incur no significant change in integrated thickness, which often serves as a volume proxy. The problem is of second order at any one scale but becomes a first order problem for non-Gaussian distributions when data are collected at different scales. We quantify the impact of spatial aliasing by computing resolution error (Er) over a range of horizontal scales (x) from 5 to 500 m. Results are summarized through a power law (Er=bxm) with distinct exponents (m) from 0.3 to 0.5 using example mathematical functions including Gaussian, inverse linear, and running mean filters. The most important finding is that a running mean filter introduces a great deal of aliasing and should be avoided whenever possible. A simple and effective substitute for the running mean is an inverse linear filter which is commonly used in numerical model data interpolation. In this study, inverse linear filters were as effective as a Gaussian filter in terms of minimizing aliasing. There is much to be gained at the community level

  11. Chest wall thickness measurements for enriched uranium: An alternative approach

    SciTech Connect

    Kramer, G.H.; Puscalau, M.

    1994-05-01

    Human Monitoring Laboratory has developed a technique to determine the chest wall thickness of an individual using information from the spectrum produced by internally deposited radionuclides. The technique has been investigated both theoretically and practically using phoswich detectors and the Lawrence Livermore Torso Phantom. The phantom was used with lung sets containing homogeneously distributed 93% enriched uranium, 20% enriched uranium, natural uranium, and {sup 241}Am. It was found that a 3-cm chest wall thickness can be estimated to within 9% when measuring 93% enriched uranium. The technique does not work for the latter two radionuclides because of an insufficient separation in the photon energies and poor resolution of the phoswich detectors. The technique is only of value for activity levels limit. 5 refs., 3 figs., 1 tab.

  12. Accuracy, Precision, Sensitivity, and Specificity of Noninvasive ICP Absolute Value Measurements.

    PubMed

    Krakauskaite, Solventa; Petkus, Vytautas; Bartusis, Laimonas; Zakelis, Rolandas; Chomskis, Romanas; Preiksaitis, Aidanas; Ragauskas, Arminas; Matijosaitis, Vaidas; Petrikonis, Kestutis; Rastenyte, Daiva

    2016-01-01

    An innovative absolute intracranial pressure (ICP) value measurement method has been validated by multicenter comparative clinical studies. The method is based on two-depth transcranial Doppler (TCD) technology and uses intracranial and extracranial segments of the ophthalmic artery as pressure sensors. The ophthalmic artery is used as a natural pair of "scales" that compares ICP with controlled pressure Pe, which is externally applied to the orbit. To balance the scales, ICP = Pe a special two-depth TCD device was used as a pressure balance indicator. The proposed method is the only noninvasive ICP measurement method that does not need patient-specific calibration.

  13. Measurement of the absolute hohlraum wall albedo under ignition foot drive conditions

    SciTech Connect

    Suter, L J; Wallace, R J; Hammel, B A; Weber, F A; Landen, O L; Campbell, K M; DeWald, E L; Glenzer, S H; Rosen, M D; Jones, O S; Turner, R E; Kauffmann, R L; Hammer, J H

    2003-11-25

    We present the first measurements of the absolute albedos of hohlraums made from gold or from high-Z mixtures. The measurements are performed over the range of radiation temperatures (70-100 eV) expected during the foot of an indirect-drive temporally-shaped ignition laser pulse, where accurate knowledge of the wall albedo (i.e. soft x-ray wall re-emission) is most critical for determining capsule radiation symmetry. We find that the gold albedo agrees well with calculations using the super transition array opacity model, potentially providing additional margin for ICF ignition.

  14. Many-wavelength interferometry with thousands of lasers for absolute distance measurement.

    PubMed

    van den Berg, S A; Persijn, S T; Kok, G J P; Zeitouny, M G; Bhattacharya, N

    2012-05-04

    We demonstrate a new technique for absolute distance measurement with a femtosecond frequency comb laser, based on unraveling the output of an interferometer to distinct comb modes with 1 GHz spacing. From the fringe patterns that are captured with a camera, a distance is derived by combining spectral and homodyne interferometry, exploiting about 9000 continuous wave lasers. This results in a measurement accuracy far within an optical fringe (λ/30), combined with a large range of nonambiguity (15 cm). Our technique merges multiwavelength interferometry and spectral interferometry, within a single scheme.

  15. Near Absolute Equation of State Measurements of CH using Velocimetry and Radiography

    NASA Astrophysics Data System (ADS)

    Fratanduono, Dayne; Celliers, Peter; Lazicki, Amy; Hawreliak, Jim; Collins, Gilbert

    2014-03-01

    The OMEGA EP laser was used to conduct absolute near equation of state measurement along the principal Hugoniot of CH to 6 Mbar. A 6 ns long, 3700 J laser pulse in direct drive was used to launch a cylindrical shock in a multi-layered aluminum/CH target which was imaged using a Fe backlighter. The technique presented here incorporated VISAR shock velocity measurements with shock compression measured using side-on radiography to determine the Hugoniot. Experimental uncertainties of less than 10% in density were obtained in these experiments. The measured Hugoniot values of this study are consistent with previous measurements that were impedance matched to quartz (Barrios et al. PoP 2010). These experiments were conducted, as proof of principle, for future absolute EOS measurements on the NIF. Future experimental work will be discussed. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

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

    PubMed

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

    2016-10-17

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

  17. First absolutely calibrated on-axis ion flow measurements in MST

    NASA Astrophysics Data System (ADS)

    Schott, B.; Baltzer, M.; Craig, D.; den Hartog, D. J.; Nishizawa, T.; Nornberg, M. D.

    2016-10-01

    Improvements in absolute calibration techniques allow for the first direct measurements of the flow profile in the core of MST. We use both active charge exchange recombination spectroscopy and passive emission near 343 nm to measure ion temperature and flow. It is generally assumed that O VI is the brightest passive emission source. However, we show that there are cases, such as high temperature, pulsed poloidal current drive (PPCD) plasmas where the passive emission is dominated by C VI. Differences in the fine structure for O VI and C VI result in a systematic velocity error of about 12 km/s if the wrong model is assumed. Active measurements, however, are relatively insensitive to background model choice. The dominant source of error in active velocity measurements remains the systematic errors in calibration. The first absolutely calibrated, localized toroidal velocity measurements were obtained using an updated calibration technique. During PPCD, the on-axis ion flow is up to 40 km/s larger than both the n = 6 mode velocity and the line-averaged ion velocity. These measurements provide the first direct look at the flow profile in the core of MST. This work has been supported by the US DOE and the Wheaton College summer research program.

  18. Absolute Position of Targets Measured Through a Chamber Window Using Lidar Metrology Systems

    NASA Technical Reports Server (NTRS)

    Kubalak, David; Hadjimichael, Theodore; Ohl, Raymond; Slotwinski, Anthony; Telfer, Randal; Hayden, Joseph

    2012-01-01

    Lidar is a useful tool for taking metrology measurements without the need for physical contact with the parts under test. Lidar instruments are aimed at a target using azimuth and elevation stages, then focus a beam of coherent, frequency modulated laser energy onto the target, such as the surface of a mechanical structure. Energy from the reflected beam is mixed with an optical reference signal that travels in a fiber path internal to the instrument, and the range to the target is calculated based on the difference in the frequency of the returned and reference signals. In cases when the parts are in extreme environments, additional steps need to be taken to separate the operator and lidar from that environment. A model has been developed that accurately reduces the lidar data to an absolute position and accounts for the three media in the testbed air, fused silica, and vacuum but the approach can be adapted for any environment or material. The accuracy of laser metrology measurements depends upon knowing the parameters of the media through which the measurement beam travels. Under normal conditions, this means knowledge of the temperature, pressure, and humidity of the air in the measurement volume. In the past, chamber windows have been used to separate the measuring device from the extreme environment within the chamber and still permit optical measurement, but, so far, only relative changes have been diagnosed. The ability to make accurate measurements through a window presents a challenge as there are a number of factors to consider. In the case of the lidar, the window will increase the time-of-flight of the laser beam causing a ranging error, and refract the direction of the beam causing angular positioning errors. In addition, differences in pressure, temperature, and humidity on each side of the window will cause slight atmospheric index changes and induce deformation and a refractive index gradient within the window. Also, since the window is a

  19. Absolute Spatially- and Temporally-Resolved Optical Emission Measurements of rf Glow Discharges in Argon

    PubMed Central

    Djurović, S.; Roberts, J. R.; Sobolewski, M. A.; Olthoff, J. K.

    1993-01-01

    Spatially- and temporally-resolved measurements of optical emission intensities are presented from rf discharges in argon over a wide range of pressures (6.7 to 133 Pa) and applied rf voltages (75 to 200 V). Results of measurements of emission intensities are presented for both an atomic transition (Ar I, 750.4 nm) and an ionic transition (Ar II, 434.8 nm). The absolute scale of these optical emissions has been determined by comparison with the optical emission from a calibrated standard lamp. All measurements were made in a well-defined rf reactor. They provide detailed characterization of local time-resolved plasma conditions suitable for the comparison with results from other experiments and theoretical models. These measurements represent a new level of detail in diagnostic measurements of rf plasmas, and provide insight into the electron transport properties of rf discharges. PMID:28053464

  20. Assessment of experimental d-PIGE γ-ray production cross sections for 12C, 14N and 16O and comparison with absolute thick target yields

    NASA Astrophysics Data System (ADS)

    Csedreki, L.; Halász, Z.; Kiss, Á. Z.

    2016-08-01

    Measured differential cross sections for deuteron induced γ-ray emission from the reactions 12C(d,pγ)13C, (Eγ = 3089 keV), 14N(d,pγ)15N (Eγ = 8310 keV) and 16O(d,pγ)17O (Eγ = 871 keV) available in the literature were assessed. In order to cross check the assessed γ-ray production cross section data, thick target γ-yields calculated from the differential cross sections were compared with available measured thick target yields. Recommended differential cross section data for each reaction were deduced for particle induced γ-ray emission (PIGE) applications.

  1. Intercomparison of the LBIR Absolute Cryogenic Radiometers to the NIST Optical Power Measurement Standard

    PubMed Central

    Fedchak, James A.; Carter, Adriaan C.; Datla, Raju

    2006-01-01

    The Low Background Infrared calibration (LBIR) facility at the National Institute of Standards and Technology (NIST) presently maintains four absolute cryogenic radiometers (ACRs) which serve as standard reference detectors for infrared calibrations performed by the facility. The primary standard for optical power measurements at NIST-Gaithersburg has been the High Accuracy Cryogenic Radiometer (HACR). Recently, an improved radiometer, the Primary Optical Watt Radiometer (POWR), has replaced the HACR as the primary standard. In this paper, we present the results of comparisons between the radiometric powers measured by the four ACRs presently maintained by the LBIR facility to that measured by the HACR and POWR. This was done by using a Si photodiode light-trapping detector as a secondary transfer standard to compare the primary national standards to the ACRs maintained by the LBIR facility. The technique used to compare an ACR to the trap detector is described in detail. The absolute optical power measurements are found to be within 0.1 % of the primary standard for all the ACRs examined in this study. PMID:27274936

  2. Absolute measurement of the 242Pu neutron-capture cross section

    DOE PAGES

    Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; ...

    2016-04-21

    Here, the absolute neutron-capture cross section of 242Pu was measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. The first direct measurement of the 242Pu(n,γ) cross section was made over the incident neutron energy range from thermal to ≈ 6 keV, and the absolute scale of the (n,γ) cross section was set according to the known 239Pu(n,f) resonance at En,R = 7.83 eV. This was accomplished by adding a small quantity of 239Pu to the 242Pu sample. The relative scale of the crossmore » section, with a range of four orders of magnitude, was determined for incident neutron energies from thermal to ≈ 40 keV. Our data, in general, are in agreement with previous measurements and those reported in ENDF/B-VII.1; the 242Pu(n,γ) cross section at the En,R = 2.68 eV resonance is within 2.4% of the evaluated value. However, discrepancies exist at higher energies; our data are ≈30% lower than the evaluated data at En ≈ 1 keV and are approximately 2σ away from the previous measurement at En ≈ 20 keV.« less

  3. Measurement of cortical thickness asymmetry in carotid occlusive disease.

    PubMed

    Asllani, Iris; Slattery, Pamelia; Fafard, Alexander; Pavol, Marykay; Lazar, Ronald M; Marshall, Randolph S

    2016-01-01

    Despite being considered an important anatomical parameter directly related to neuronal density, cortical thickness is not routinely assessed in studies of the human brain in vivo. This paucity has been largely due to the size and convoluted shape of the human cortex, which has made it difficult to develop automated algorithms that can measure cortical thickness efficiently and reliably. Since the development of such an algorithm by Fischl and Dale in 2000, the number of studies investigating the relationship between cortical thickness and other physiological parameters in the brain has been on the rise. There have been no studies however that have validated cortical asymmetry against known vascular anatomy. To this aim, using high-resolution MRI, we measured cortical thickness and volume in the primary motor (M1) and primary visual (V1) cortex in patients with unilateral, high-grade carotid occlusive disease (n = 29, age = 74 ± 10 years). These regions were selected based on the hypothesis that there will be thinning of the cortical thickness of M1 in the territory supplied by the occluded carotid artery, whereas V1 will show no asymmetry since its blood supply is provided by unaffected posterior arteries. To test for an effect of handedness, cortical thickness and volume were also measured in healthy volunteers (n = 8, age = 37 ± 13 years). In patients, we found thinner cortex in M1 on the occluded side (mean = 2.07 ± 0.19 mm vs 2.15 ± 0.20 mm, p = 0.0008) but no hemispheric difference in V1 (1.80 ± 0.17 mm in occluded vs 1.78 ± 0.16 mm in unoccluded, p = 0.31). Although the mean cortical volume of M1 in the occluded hemisphere was also lower, the difference did not reach statistical significance (p = 0.09). Similarly, in healthy controls, the results showed no hemispheric asymmetry in either cortical thickness or volume in either region (p > 0.1). To test for an orientation bias in the method, the analysis was repeated

  4. Absolute Retinal Blood Flow Measurement With a Dual-Beam Doppler Optical Coherence Tomography

    PubMed Central

    Dai, Cuixia; Liu, Xiaojing; Zhang, Hao F.; Puliafito, Carmen A.; Jiao, Shuliang

    2013-01-01

    Purpose. To test the capability of a novel dual-beam Doppler optical coherence tomography (OCT) technique for simultaneous in vivo measurement of the Doppler angle and, thus, the absolute retinal blood velocity and the retinal flow rate, without the influence of motion artifacts. Methods. A novel dual-beam Doppler spectral domain OCT (SD-OCT) was developed. The two probing beams are separated with a controllable distance along an arbitrary direction, both of which are controlled by two independent 2D optical scanners. Two sets of optical Doppler tomography (ODT) images are acquired simultaneously. The Doppler angle of each blood vessel segment is calculated from the relative coordinates of the centers of the blood vessel in the two corresponding ODT images. The absolute blood flow velocity and the volumetric blood flow rate can then be calculated. To measure the total retinal blood flow, we used a circular scan pattern centered at the optic disc to obtain two sets of concentric OCT/ODT images simultaneously. Results. We imaged two normal human subjects at ages of 48 and 34 years. The total retinal blood flow rates of the two human subjects were calculated to be 47.01 μL/min (older subject) and 51.37 μL/min (younger subject), respectively. Results showed that the performance of this imaging system is immune to eye movement, since the two sets of ODT images were acquired simultaneously. Conclusions. The dual-beam OCT/ODT system is successful in measuring the absolute retinal blood velocity and the volumetric flow rate. The advantage of the technique is that the two sets of ODT images used for the calculation are acquired simultaneously, which eliminates the influence of eye motion and ensures the accuracy of the calculated hemodynamic parameters. PMID:24222303

  5. Absolute Density Calibration Cell for Laser Induced Fluorescence Erosion Rate Measurements

    NASA Technical Reports Server (NTRS)

    Domonkos, Matthew T.; Stevens, Richard E.

    2001-01-01

    Flight qualification of ion thrusters typically requires testing on the order of 10,000 hours. Extensive knowledge of wear mechanisms and rates is necessary to establish design confidence prior to long duration tests. Consequently, real-time erosion rate measurements offer the potential both to reduce development costs and to enhance knowledge of the dependency of component wear on operating conditions. Several previous studies have used laser-induced fluorescence (LIF) to measure real-time, in situ erosion rates of ion thruster accelerator grids. Those studies provided only relative measurements of the erosion rate. In the present investigation, a molybdenum tube was resistively heated such that the evaporation rate yielded densities within the tube on the order of those expected from accelerator grid erosion. This work examines the suitability of the density cell as an absolute calibration source for LIF measurements, and the intrinsic error was evaluated.

  6. Absolute measurement of ultrasonic non-linearity parameter at contact interface

    NASA Astrophysics Data System (ADS)

    Yuan, Maodan; Lee, Taekgyu; Kang, To; Zhang, Jianhai; Song, Sung-Jin; Kim, Hak-Joon

    2015-10-01

    Non-linear interaction of waves with contact interfaces has been widely applied in non-destructive evaluation fields such as bonding quality evaluation, and the detection of closed microcracks and composite delamination. This paper proposes an absolute measurement of the ultrasonic non-linearity parameter using a piezoelectric detection method for two aluminum alloy blocks of different lengths. The results of a two-dimensional finite element method model verified by models for hard and soft contact interfaces, depending on the interface property, were compared with the measured non-linearity parameter. The measured values show good agreement with the modelled results, indicating good potential for measuring the non-linearity parameter at interfaces experimentally and numerically.

  7. Measurements of the absolute branching fractions of B+/- --> K+/-X(cc).

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Karyotakis, Y; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Grauges, E; Palano, A; Pappagallo, M; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schroeder, T; Steinke, M; Boyd, J T; Burke, J P; Chevalier, N; Cottingham, W N; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Teodorescu, L; Blinov, A E; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Weinstein, A J R; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Minamora, J S; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Andreassen, R; Mancinelli, G; Meadows, B T; Sokoloff, M D; Blanc, F; Bloom, P; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nauenberg, U; Olivas, A; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q; Altenburg, D; Feltresi, E; Hauke, A; Spaan, B; Brandt, T; Brose, J; Dickopp, M; Klose, V; Lacker, H M; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Bernard, D; Bonneaud, G R; Grenier, P; Schrenk, S; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Wu, J; Dubitzky, R S; Langenegger, U; Marks, J; Schenk, S; Uwer, U; Schott, G; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Gaillard, J R; Nash, J A; Nikolich, M B; Vazquez, W Panduro; Chai, X; Charles, M J; Mader, W F; Mallik, U; Mohapatra, A K; Ziegler, V; Cochran, J; Crawley, H B; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Arnaud, N; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Le Diberder, F; Lepeltier, V; Lutz, A M; Oyanguren, A; Petersen, T C; Plaszczynski, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Parry, R J; Payne, D J; Schofield, K C; Touramanis, C; Cormack, C M; Di Lodovico, F; Menges, W; Sacco, R; Brown, C L; Cowan, G; Flaecher, H U; Green, M G; Hopkins, D A; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Edgar, C L; Hodgkinson, M C; Kelly, M P; Lafferty, G D; Naisbit, M T; Williams, J C; Chen, C; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Kofler, R; Koptchev, V B; Li, X; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Koeneke, K; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Viaud, B; Nicholson, H; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; Losecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Lu, M; Potter, C T; Sinev, N B; Strom, D; Strube, J; Torrence, E; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; John, M J J; Leruste, Ph; Malclès, J; Ocariz, J; Roos, L; Therin, G; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Biasini, M; Covarelli, R; Pacetti, S; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Walsh, J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Marco, E Di; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Gioi, L Li; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Tehrani, F Safai; Voena, C; Schröder, H; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Gopal, G P; Olaiya, E O; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Graziani, G; de Monchenault, G Hamel; Kozanecki, W; Legendre, M; London, G W; Mayer, B; Vasseur, G; Yèche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Wilson, J R; Yumiceva, F X; Abe, T; Allen, M T; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Claus, R; Coleman, J P; Convery, M R; Cristinziani, M; Dingfelder, J C; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Fan, S; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Vitale, L; Martinez-Vidal, F; Panvini, R S; Banerjee, Sw; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Eichenbaum, A M; Flood, K T; Graham, M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Mellado, B; Mihalyi, A; Pan, Y; Pierini, M; Prepost, R; Tan, P; Wu, S L; Yu, Z; Neal, H

    2006-02-10

    We study the two-body decays of B+/- mesons to K+/- and a charmonium state X(cc) in a sample of 210.5 fb(-1) of data from the BABAR experiment. We perform measurements of absolute branching fractions beta(B+/- --> K+/-X(cc)) using a missing mass technique, and report several new or improved results. In particular, the upper limit beta(B+/- --> K+/- X(3872)) < 3.2 x 10(-4) at 90% C.L. and the inferred lower limit beta(X(3872)J/psipi+ pi-) > 4.2% will help in understanding the nature of the recently discovered X(3872).

  8. Measurement of the absolute branching fraction of D0-->K-pi+.

    PubMed

    Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Garra Tico, J; Grauges, E; Lopez, L; Palano, A; Eigen, G; Ofte, I; Stugu, B; Sun, L; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Tackmann, K; Wenzel, W A; Del Amo Sanchez, P; Hawkes, C M; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Schroeder, T; Steinke, M; Cottingham, W N; Walker, D; Asgeirsson, D J; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Saleem, M; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Liu, F; Long, O; Shen, B C; Zhang, L; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Schalk, T; Schumm, B A; Seiden, A; Williams, D C; Wilson, M G; Winstrom, L O; Chen, E; Cheng, C H; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Gabareen, A M; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Lombardo, V; Thiebaux, Ch; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Franchini, P; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Santoro, V; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Nikolich, M B; Panduro Vazquez, W; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Guo, Z J; Lae, C K; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Béquilleux, J; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; George, K A; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flaecher, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Fisher, P H; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; McLachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; De Nardo, G; Fabozzi, F; Lista, L; Monorchio, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; Losecco, J M; Benelli, G; Corwin, L A; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Ter-Antonyan, R; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gagliardi, N; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; Hartfiel, B L; Leruste, Ph; Malclès, J; Ocariz, J; Perez, A; Gladney, L; Biasini, M; Covarelli, R; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Calderini, G; Carpinelli, M; Cenci, R; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Biesiada, J; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Baracchini, E; Bellini, F; Cavoto, G; D'Orazio, A; Del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Renga, F; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; Castelli, G; Franek, B; Olaiya, E O; Ricciardi, S; Roethel, W; Wilson, F F; Aleksan, R; Emery, S; Escalier, M; Gaidot, A; Ganzhur, S F; de Monchenault, G Hamel; Kozanecki, W; Legendre, M; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, H; Kim, P; Leith, D W G S; Li, S; Luitz, S; Luth, V; Lynch, H L; Macfarlane, D B; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Milanes, D A; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Hamano, K; Kowalewski, R; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Dasu, S; Flood, K T; Hollar, J J; Kutter, P E; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Yu, Z; Neal, H

    2008-02-08

    We measure the absolute branching fraction for D(0)-->K(-)pi(+) using partial reconstruction of B(0)-->D(*+)Xl(-)nu(l) decays, in which only the charged lepton and the pion from the decay D(*+)-->D(0)pi(+) are used. Based on a data sample of 230 x 10(6) BB pairs collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we obtain B(D(0)-->K(-)pi(+)) = (4.007+/-0.037+/-0.072)%, where the first uncertainty is statistical and the second is systematic.

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

    NASA Astrophysics Data System (ADS)

    Schödel, R.

    2015-08-01

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

  10. Length measurement in absolute scale via low-dispersion optical cavity

    NASA Astrophysics Data System (ADS)

    Pravdova, Lenka; Lesundak, Adam; Smid, Radek; Hrabina, Jan; Rerucha, Simon; Cip, Ondrej

    2016-12-01

    We report on the length measuring instrument with the absolute scale that was based on the combination of an optical frequency comb and a passive optical cavity. The time spacing of short femtosecond pulses, generated by the optical frequency comb, is optically phase locked onto the cavity free spectral range with a derivative spectroscopy technique so that the value of the repetition frequency of the femtosecond laser is tied to and determines the measured displacement. The instantaneous value of the femtosecond pulse train frequency is counted by a frequency counter. This counted value corresponds to the length given by the spacing between the two mirrors of the passive cavity. The phase lock between the femtosecond pulsed beam and the passive cavity is possible due to the low-dispersion of the cavity mirrors, where the silver coating on the mirrors was used to provide the low dispersion for the broadband radiation of the comb. Every reflection on the output mirror feeds a portion of the beam back to the cavity so that the output beam is a result of multiple interfering components. The parameters of the output beam are given not only by the parameters of the mirrors but mainly by the absolute distance between the mirror surfaces. Thus, one cavity mirror can be considered as the reference starting point of the distance to be measured and the other mirror is the measuring probe surveying the unknown distance. The measuring mirror of the experimental setup of the low-dispersion cavity is mounted on a piezoelectric actuator which provides small changes in the cavity length we used to test the length measurement method. For the verification of the measurement accuracy a reference incremental interferometer was integrated into our system so that the displacement of the piezoelectric actuator could be obtained with both measuring methods simultaneously.

  11. High-resolution measurement of absolute {alpha}-decay widths in {sup 16}O

    SciTech Connect

    Wheldon, C.; Ashwood, N. I.; Barr, M.; Curtis, N.; Freer, M.; Kokalova, Tz.; Malcolm, J. D.; Spencer, S. J.; Ziman, V. A.; Faestermann, Th.; Kruecken, R.; Wirth, H.-F.; Hertenberger, R.; Lutter, R.; Bergmaier, A.

    2011-06-15

    By using a large-acceptance position-sensitive silicon detector array in coincidence with the high-resolution Munich Q3D spectrograph, unambiguous measurements have been made of the absolute {alpha}-particle decay widths from excited states in {sup 16}O* in the energy range 13.85 to 15.87 MeV. Carbon targets have been bombarded with 42-MeV {sup 6}Li beams to induce {sub 6}{sup 12}C({sub 3}{sup 6}Li, d){sub 8}{sup 16}O* reactions. The deuteron ejectiles were measured in the Q3D and the results gated by {sup 4}He+{sup 12}C breakup products detected in the silicon array, the efficiency of which was modeled using Monte Carlo simulations. By comparing total population and breakup-gated spectra, the following absolute {alpha}-decay widths have been measured with high resolution: {Gamma}{sub {alpha}}0/{Gamma}{sub tot} = 0.87{+-}0.11 (13.980 MeV), 1.04{+-}0.15 (14.302 MeV), 0.92{+-}0.10 (14.399 MeV), 0.59{+-}0.04 (14.815 MeV), 0.88{+-}0.18 (15.785 MeV), and {Gamma}{sub {alpha}}1/{Gamma}{sub tot}=1.14{+-}0.08 (14.660 MeV), 0.46{+-}0.06 (14.815 MeV).

  12. Refractive index and thickness of coating measurement interferometer

    NASA Astrophysics Data System (ADS)

    Wu, Chao-Yuan; Wu, Kai; Chen, Sheng-Hui; Lee, Cheng-Chung

    2009-08-01

    We proposed a method to measure the optical constants of thin film through polarizing phase shifting interferometer based on Twyman-Green interferometer structure. A broadband light source coming with a narrow band-pass filter was used to generate a low coherence light and the wavelength is tunable by changing the filter. A pixelated micro-polarizer mask on the detection camera made phase shifting array to make different phase shifts at once. Therefore, we can use one single interferogram to extract phase information, and it is effective in reducing environmental vibration. The refractive index and thickness of thin film can be derived from the obtained reflection coefficient's magnitude and phase. The measurement results were compared with the results obtained by an ellipsometer.

  13. Absolute group refractive index measurement of air by dispersive interferometry using frequency comb.

    PubMed

    Yang, L J; Zhang, H Y; Li, Y; Wei, H Y

    2015-12-28

    The absolute group refractive index of air at 1563 nm is measured by dispersive interferometry, and a combined uncertainty of 1.2 × 10(-8) is achieved. The group refractive index of air is calculated from the dispersive interferograms of the two beams passing through the inner and outer regions of a vacuum cell by fast-Fourier-transform. Experimental results show that the discrepancies between our method and modified Edlén equation are less than 3.43 × 10(-8) and 4.4 × 10(-8) for short-term and long-term experiments, respectively. The interferogram update rate is 15 ms, which makes it suitable for application of real-time monitoring. Furthermore, it is promising to improve the measurement uncertainty to 3.0 × 10(-9) by changing the material of the vacuum cell and measuring its length more accurately through optical interferometry.

  14. ABSOLUTE MEASUREMENT OF THE POLARIZATION OF HIGH ENERGY PROTON BEAMS AT RHIC

    SciTech Connect

    MAKDISI,Y.; BRAVAR, A. BUNCE, G. GILL, R.; HUANG, H.; ET AL.

    2007-06-25

    The spin physics program at the Relativistic Heavy Ion Collider (RHIC) requires knowledge of the beam polarization to better than 5%. Such a goal is made the more difficult by the lack of knowledge of the analyzing power of high energy nuclear physics processes. To overcome this, a polarized hydrogen jet target was constructed and installed at one intersection region in RHIC where it intersects both beams and utilizes the precise knowledge of the jet atomic hydrogen beam polarization to measure the analyzing power in proton-proton elastic scattering in the Nuclear Coulomb Interference (CNI) region at the prescribed RHIC proton beam energy. The reverse reaction is used to assess the absolute beam polarization. Simultaneous measurements taken with fast high statistics polarimeters that measure the p-Carbon elastic scattering process also in the CNI region use the jet results to calibrate the latter.

  15. Measurement of the absolute wavefront curvature radius in a heterodyne interferometer.

    PubMed

    Hechenblaikner, Gerald

    2010-09-01

    We present an analytical derivation of the coupling parameter relating the angle between two interfering beams in a heterodyne interferometer to the differential phase signals detected by a quadrant photodiode. This technique, also referred to as differential wavefront sensing, is commonly used in space-based gravitational wave detectors to determine the attitude of a test mass in one of the interferometer arms from the quadrant diode signals. Successive approximations to the analytical expression are made to simplify the investigation of parameter dependencies. Motivated by our findings, we propose what we believe to be a new measurement method to accurately determine the absolute wavefront curvature of a single measurement beam. We also investigate the change in the coupling parameter when the interferometer "test mirror" is moved from its nominal position, an effect which mediates the coupling of mirror displacement noise into differential phase measurements.

  16. Superharp — A wire scanner with absolute position readout for beam energy measurement at CEBAF

    NASA Astrophysics Data System (ADS)

    Yan, C.; Adderley, P.; Barker, D.; Beaufait, J.; Capek, K.; Carlini, R.; Dahlberg, J.; Feldl, E.; Jordan, K.; Kross, B.; Oren, W.; Wojcik, R.; VanDyke, J.

    1995-02-01

    The CEBAF superharp is an upgraded beam wire scanner which provides absolute beam position readout using a shaft encoder. Superharps allow for high precision measurements of the beam's profile and position ( Δx ˜ 10 μm). The Hall C endstation at CEBAF will use three pairs of superharps to perform beam energy measurements with 10 -3 accuracy. The three pairs are installed at the beginning, the mid-point and the end of the Hall C arc beamline. Using superharps in conjunction with a dual sensor system: the direct current pick-up and the bremsstrahlung detectors, beam profile measurements can be obtained over a wide beam current range of 1 ˜ 200 μA.

  17. Absolute single photoionization cross-section measurements of Rb2+ ions: experiment and theory

    NASA Astrophysics Data System (ADS)

    Macaluso, D. A.; Bogolub, K.; Johnson, A.; Aguilar, A.; Kilcoyne, A. L. D.; Bilodeau, R. C.; Bautista, M.; Kerlin, A. B.; Sterling, N. C.

    2016-12-01

    Absolute single photoionization cross-section measurements of Rb2+ ions were performed using synchrotron radiation and the photo-ion, merged-beams technique at the Advanced Light Source at Lawrence Berkeley National Laboratory. Measurements were made at a photon energy resolution of 13.5 ± 2.5 meV from 37.31 to 44.08 eV spanning the 2P{}3/2o ground state and 2P{}1/2o metastable state ionization thresholds. Multiple autoionizing resonance series arising from each initial state are identified using quantum defect theory. The measurements are compared to Breit-Pauli R-matrix calculations with excellent agreement between theory and experiment.

  18. Intensity evaluation using a femtosecond pulse laser for absolute distance measurement.

    PubMed

    Wu, Hanzhong; Zhang, Fumin; Li, Jianshuang; Cao, Shiying; Meng, Xiangsong; Qu, Xinghua

    2015-06-10

    In this paper, we propose a method of intensity evaluation based on different pulse models using a femtosecond pulse laser, which enables long-range absolute distance measurement with nanometer precision and large non-ambiguity range. The pulse cross-correlation is analyzed based on different pulse models, including Gaussian, Sech(2), and Lorenz. The DC intensity and the amplitude of the cross-correlation patterns are also demonstrated theoretically. In the experiments, we develop a new combined system and perform the distance measurements on an underground granite rail system. The DC intensity and amplitude of the interference fringes are measured and show a good agreement with the theory, and the distance to be determined can be up to 25 m using intensity evaluation, within 64 nm deviation compared with a He-Ne incremental interferometer, and corresponds to a relative precision of 2.7×10(-9).

  19. Absolute measurement of the relativistic magnetic dipole transition energy in heliumlike argon.

    PubMed

    Amaro, Pedro; Schlesser, Sophie; Guerra, Mauro; Le Bigot, Eric-Olivier; Isac, Jean-Michel; Travers, Pascal; Santos, José Paulo; Szabo, Csilla I; Gumberidze, Alexandre; Indelicato, Paul

    2012-07-27

    The 1s2s (3)S(1)→1s(2) (1)S(0) relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron-cyclotron resonance ion source, has been measured using a double-flat crystal x-ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference-free) measurements in the x-ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy). This value is the most accurate, reference-free measurement done for such a transition and is in good agreement with recent QED predictions.

  20. Measurements Of Absolute Ca II H And K Flux In FGKM Stars

    NASA Astrophysics Data System (ADS)

    Marvin, Christopher; Reiners, A.; Anglada-Escudé, G.; Jeffers, S.; Boro-Saikia, S.

    2016-09-01

    M dwarfs are the most numerous stars in the universe, yet they still lack absolute chromospheric Ca II H and K (R'_HK) calibrations to effectively compare their activity with FGK stars. We scale high-S/N, high-resolution template spectra, obtained by co-adding multiple HARPS spectra of the same star, to PHOENIX stellar atmosphere models, and obtain chromospheric line measurements of Ca II H & K in physical units of 106 M dwarfs. We also derive new Mt. Wilson S-index to R'_HK conversions appropriate for cooler stars, ranging from 0.82 <= B-V <= 2.00. We establish a chromospheric activity database by combining archival data of FGK stars and using our technique to extend absolute chromospheric measurements to M dwarfs. Our results show that using model atmospheres provides a reliable way to scale uncalibrated spectra and also estimate photospheric flux for M dwarfs, but note that accurate stellar parameter determination is essential to compare chromospheric emission of different spectral types.

  1. Measurement of absolute arterial cerebral blood volume in human brain without using a contrast agent.

    PubMed

    Hua, Jun; Qin, Qin; Pekar, James J; van Zijl, Peter C M

    2011-12-01

    Arterial cerebral blood volume (CBV(a) ) is a vital indicator of tissue perfusion and vascular reactivity. We extended the recently developed inflow vascular-space-occupancy (iVASO) MRI technique, which uses spatially selective inversion to suppress the signal from blood flowing into a slice, with a control scan to measure absolute CBV(a) using cerebrospinal fluid (CSF) for signal normalization. Images were acquired at multiple blood nulling times to account for the heterogeneity of arterial transit times across the brain, from which both CBV(a) and arterial transit times were quantified. Arteriolar CBV(a) was determined separately by incorporating velocity-dependent bipolar crusher gradients. Gray matter (GM) CBV(a) values (n=11) were 2.04 ± 0.27 and 0.76 ± 0.17 ml blood/100 ml tissue without and with crusher gradients (b=1.8 s/mm(2) ), respectively. Arterial transit times were 671 ± 43 and 785 ± 69 ms, respectively. The arterial origin of the signal was validated by measuring its T(2) , which was within the arterial range. The proposed approach does not require exogenous contrast agent administration, and provides a non-invasive alternative to existing blood volume techniques for mapping absolute CBV(a) in studies of brain physiology and neurovascular diseases.

  2. Relative and absolute reliability of measures of linoleic acid-derived oxylipins in human plasma.

    PubMed

    Gouveia-Figueira, Sandra; Bosson, Jenny A; Unosson, Jon; Behndig, Annelie F; Nording, Malin L; Fowler, Christopher J

    2015-09-01

    Modern analytical techniques allow for the measurement of oxylipins derived from linoleic acid in biological samples. Most validatory work has concerned extraction techniques, repeated analysis of aliquots from the same biological sample, and the influence of external factors such as diet and heparin treatment upon their levels, whereas less is known about the relative and absolute reliability of measurements undertaken on different days. A cohort of nineteen healthy males were used, where samples were taken at the same time of day on two occasions, at least 7 days apart. Relative reliability was assessed using Lin's concordance correlation coefficients (CCC) and intraclass correlation coefficients (ICC). Absolute reliability was assessed by Bland-Altman analyses. Nine linoleic acid oxylipins were investigated. ICC and CCC values ranged from acceptable (0.56 [13-HODE]) to poor (near zero [9(10)- and 12(13)-EpOME]). Bland-Altman limits of agreement were in general quite wide, ranging from ±0.5 (12,13-DiHOME) to ±2 (9(10)-EpOME; log10 scale). It is concluded that relative reliability of linoleic acid-derived oxylipins varies between lipids with compounds such as the HODEs showing better relative reliability than compounds such as the EpOMEs. These differences should be kept in mind when designing and interpreting experiments correlating plasma levels of these lipids with factors such as age, body mass index, rating scales etc.

  3. Absolute distance measurement by intensity detection using a mode-locked femtosecond pulse laser.

    PubMed

    Wu, Hanzhong; Zhang, Fumin; Cao, Shiying; Xing, Shujian; Qu, Xinghua

    2014-05-05

    We propose an interferometric method that enables to measure a distance by the intensity measurement using the scanning of the interferometer reference arm and the recording of the interference fringes including the brightest fringe. With the consideration of the dispersion and absorption of the pulse laser in a dispersive and absorptive medium, we investigate the cross-correlation function between two femtosecond laser pulses in the time domain. We also introduce the measurement principle. We study the relationship between the position of the brightest fringe and the distance measured, which can contribute to the distance measurement. In the experiments, we measure distances using the method of the intensity detection while the reference arm of Michelson interferometer is scanned and the fringes including the brightest fringe is recorded. Firstly we measure a distance in a range of 10 µm. The experimental results show that the maximum deviation is 45 nm with the method of light intensity detection. Secondly, an interference system using three Michelson interferometers is developed, which combines the methods of light intensity detection and time-of-flight. This system can extend the non-ambiguity range of the method of light intensity detection. We can determine a distance uniquely with a larger non-ambiguity range. It is shown that this method and system can realize absolute distance measurement, and the measurement range is a few micrometers in the vicinity of Nl(pp), where N is an integer, and lpp is the pulse-to-pulse length.

  4. Absolute reliability of isokinetic knee flexion and extension measurements adopting a prone position.

    PubMed

    Ayala, F; De Ste Croix, M; Sainz de Baranda, P; Santonja, F

    2013-01-01

    The main purpose of this study was to determine the absolute and relative reliability of isokinetic peak torque (PT), angle of peak torque (APT), average power (PW) and total work (TW) for knee flexion and extension during concentric and eccentric actions measured in a prone position at 60, 180 and 240° s(-1). A total of 50 recreational athletes completed the study. PT, APT, PW and TW for concentric and eccentric knee extension and flexion were recorded at three different angular velocities (60, 180 and 240° s(-1)) on three different occasions with a 72- to 96-h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CV(TE)), percentage change in the mean (ChM) and relative reliability with intraclass correlations (ICC(3,1)). For both the knee extensor and flexor muscle groups, all strength data (except APT during knee flexion movements) demonstrated moderate absolute reliability (ChM < 3%; ICCs > 0·70; and CV(TE) < 20%) independent of the knee movement (flexion and extension), type of muscle action (concentric and eccentric) and angular velocity (60, 180 and 240° s(-1)). Therefore, the current study suggests that the CV(TE) values reported for PT (8-20%), APT (8-18%) (only during knee extension movements), PW (14-20%) and TW (12-28%) may be acceptable to detect the large changes usually observed after rehabilitation programmes, but not acceptable to examine the effect of preventative training programmes in healthy individuals.

  5. Microfabricated Collector-Generator Electrode Sensor for Measuring Absolute pH and Oxygen Concentrations.

    PubMed

    Dengler, Adam K; Wightman, R Mark; McCarty, Gregory S

    2015-10-20

    Fast-scan cyclic voltammetry (FSCV) has attracted attention for studying in vivo neurotransmission due to its subsecond temporal resolution, selectivity, and sensitivity. Traditional FSCV measurements use background subtraction to isolate changes in the local electrochemical environment, providing detailed information on fluctuations in the concentration of electroactive species. This background subtraction removes information about constant or slowly changing concentrations. However, determination of background concentrations is still important for understanding functioning brain tissue. For example, neural activity is known to consume oxygen and produce carbon dioxide which affects local levels of oxygen and pH. Here, we present a microfabricated microelectrode array which uses FSCV to detect the absolute levels of oxygen and pH in vitro. The sensor is a collector-generator electrode array with carbon microelectrodes spaced 5 μm apart. In this work, a periodic potential step is applied at the generator producing transient local changes in the electrochemical environment. The collector electrode continuously performs FSCV enabling these induced changes in concentration to be recorded with the sensitivity and selectivity of FSCV. A negative potential step applied at the generator produces a transient local pH shift at the collector. The generator-induced pH signal is detected using FSCV at the collector and correlated to absolute solution pH by postcalibration of the anodic peak position. In addition, in oxygenated solutions a negative potential step at the generator produces hydrogen peroxide by reducing oxygen. Hydrogen peroxide is detected with FSCV at the collector electrode, and the magnitude of the oxidative peak is proportional to absolute oxygen concentrations. Oxygen interference on the pH signal is minimal and can be accounted for with a postcalibration.

  6. Measurements of absolute absorption cross sections of ozone in the 185- to 254-nm wavelength region and the temperature dependence

    NASA Technical Reports Server (NTRS)

    Yoshino, K.; Esmond, J. R.; Freeman, D. E.; Parkinson, W. H.

    1993-01-01

    Laboratory measurements of the relative absorption cross sections of ozone at temperatures 195, 228, and 295 K have been made throughout the 185 to 254 nm wavelength region. The absolute absorption cross sections at the same temperatures have been measured at several discrete wavelengths in the 185 to 250 nm region. The absolute cross sections of ozone have been used to put the relative cross sections on a firm absolute basis throughout the 185 to 255 nm region. These recalibrated cross sections are slightly lower than those of Molina and Molina (1986), but the differences are within a few percent and would not be significant in atmospheric applications.

  7. The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF

    DOE PAGES

    Casey, D. T.; Frenje, J. A.; Gatu Johnson, M.; ...

    2013-04-18

    The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, iontemperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describesmore » ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.« less

  8. The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF

    NASA Astrophysics Data System (ADS)

    Casey, D. T.; Frenje, J. A.; Gatu Johnson, M.; Séguin, F. H.; Li, C. K.; Petrasso, R. D.; Glebov, V. Yu.; Katz, J.; Magoon, J.; Meyerhofer, D. D.; Sangster, T. C.; Shoup, M.; Ulreich, J.; Ashabranner, R. C.; Bionta, R. M.; Carpenter, A. C.; Felker, B.; Khater, H. Y.; LePape, S.; MacKinnon, A.; McKernan, M. A.; Moran, M.; Rygg, J. R.; Yeoman, M. F.; Zacharias, R.; Leeper, R. J.; Fletcher, K.; Farrell, M.; Jasion, D.; Kilkenny, J.; Paguio, R.

    2013-04-01

    The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, ion-temperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describes ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.

  9. Absolute measurement of enhanced fluctuations in assemblies of biomolecules by ultrasonic techniques.

    PubMed Central

    Cerf, R

    1985-01-01

    By expressing the fluctuation-dissipation theorem explicitly, equations are obtained for the ultrasonic relaxation amplitudes that contain one single molecular parameter, i.e., the fluctuation, or the sum of fluctuations. The absolute measurement of this parameter is therefore possible. The equations apply to a two-state system, to a multistate system and to a linear Ising chain as well. In an aqueous medium, where molar volume changes are important, the ultrasonic relaxation amplitudes are proportional to the volume fluctuations. For assemblies of biomolecules that exhibit enhanced ultrasonic absorption on assembly it is possible to measure the increase on assembly of the sum of fluctuations. In view of application to tobacco mosaic virus protein aggregates, examples are given in which the fluctuations associated with two normal modes of relaxation are equally enhanced when the difference of conformational stability of the states is reduced. The corresponding observable changes of the ultrasonic spectra are described. PMID:4016196

  10. Absolute ultrasonic displacement amplitude measurements with a submersible electrostatic acoustic transducer

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cantrell, John H.

    1992-01-01

    An experimental technique for absolute measurement of ultrasonic wave particle displacement amplitudes in liquids is reported. The technique is capable of measurements over a frequency range of two decades with a sensitivity less than one angstrom. The technique utilizes a previously reported submersible electrostatic acoustic transducer (ESAT) featuring a conductive membrane stretched over a recessed electrode. An uncertainty analysis shows that the displacement amplitude of an ultrasonic plane wave incident on the ESAT can be experimentally determined to better than 2.3-4 percent, depending on frequency, in the frequency range of 0.5-15 MHz. Membranes with lower and more uniform areal densities can improve the accuracy and extend the operation to higher frequencies.

  11. Absolute measurement of aspheric lens with electrically tunable lens in digital holography

    NASA Astrophysics Data System (ADS)

    Wang, Zhaomin; Qu, Weijuan; Yang, Fang; Tian, Ailing; Asundi, Anand

    2017-01-01

    A novel method for testing aspheric lenses using digital holography with an electrically tunable lens (ETL) is proposed and experimentally verified. The ETL generates a tunable deformed wavefront which helps to decrease the high gradient of aspheric lenses. By decomposing the aspheric surface into two resolvable ones, its absolute phase can be determined using a double-exposure measurement. In this method, the wavefront generated by the ETL need not be identical to the aspheric surface as in conventional null interferometer system, but just sufficient to resolve the high gradient surface. On the other hand, the tunability of the ETL allows generation of wavefronts which can be used to test different aspheric lens. Furthermore, advantages of the ETL such as low cost, fast response, and compact configuration make the proposed method a promising technique for aspheric surface measurement.

  12. The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF.

    PubMed

    Casey, D T; Frenje, J A; Johnson, M Gatu; Séguin, F H; Li, C K; Petrasso, R D; Glebov, V Yu; Katz, J; Magoon, J; Meyerhofer, D D; Sangster, T C; Shoup, M; Ulreich, J; Ashabranner, R C; Bionta, R M; Carpenter, A C; Felker, B; Khater, H Y; LePape, S; MacKinnon, A; McKernan, M A; Moran, M; Rygg, J R; Yeoman, M F; Zacharias, R; Leeper, R J; Fletcher, K; Farrell, M; Jasion, D; Kilkenny, J; Paguio, R

    2013-04-01

    The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, ion-temperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describes ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.

  13. Absolute measurements of night-time electron density using ISR gyro lines

    NASA Astrophysics Data System (ADS)

    Bhatt, Asti; Kelley, Michael; Nicolls, Michael; Sulzer, Michael

    2012-07-01

    Gyro line in Incoherent Scatter Spectrum is the underused cousin of the more popular Plasma line. This is because it is very weak during the day and stronger during dawn and dusk hours. When the electron density is such that the electron plasma frequency drops below the electron gyro frequency, the gyro line frequency becomes proportional to the electron density. This is during a time when the plasma line is no longer detected, and we have no other means for getting precise measurements for absolute electron density. In this paper, we will present a linear equation for the gyro line frequency and measurements from the Arecibo radar in Puerto Rico, showing comparison with the plasma line data and derived electron density.

  14. Diagnostics principle of microwave cut-off probe for measuring absolute electron density

    SciTech Connect

    Jun, Hyun-Su

    2014-08-15

    A generalized diagnostics principle of microwave cut-off probe is presented with a full analytical solution. In previous studies on the microwave cut-off measurement of weakly ionized plasmas, the cut-off frequency ω{sub c} of a given electron density is assumed to be equal to the plasma frequency ω{sub p} and is predicted using electromagnetic simulation or electric circuit model analysis. However, for specific plasma conditions such as highly collisional plasma and a very narrow probe tip gap, it has been found that ω{sub c} and ω{sub p} are not equal. To resolve this problem, a generalized diagnostics principle is proposed by analytically solving the microwave cut-off condition Re[ε{sub r,eff}(ω = ω{sub c})] = 0. In addition, characteristics of the microwave cut-off condition are theoretically tested for correct measurement of the absolute electron density.

  15. Measurement of the absolute branching fraction for Λc+ → Λμ+νμ

    NASA Astrophysics Data System (ADS)

    Ablikim, M.; Achasov, M. N.; Ahmed, S.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S.; Chen, S. J.; Chen, X.; Chen, X. R.; Chen, Y. B.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fan, J. Z.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Farinelli, R.; Fava, L.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, Y.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, R. P.; Guo, Y.; Guo, Y. P.; Haddadi, Z.; Hafner, A.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.; Hussain, T.; Ikegami Andersson, W.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, L. W.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Kiese, P.; Kliemt, R.; Kloss, B.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kupsc, A.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Lavezzi, L.; Leithoff, H.; Leng, C.; Li, C.; Cheng, Li; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, Lei.; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Y. B.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, Q. J.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Y. Y.; Liu, Z. A.; Liu, Z. Q.; Loehner, H.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Muchnoi, N. Yu.; Muramatsu, H.; Musiol, P.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, L. Q.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Ripka, M.; Rong, G.; Rosner, Ch.; Ruan, X. D.; Sarantsev, A.; Savrié, M.; Schnier, C.; Schoenning, K.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Song, W. M.; Song, X. Y.; Sosio, S.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Tiemens, M.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, W.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Weber, T.; Wei, D. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, L. G.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Z. J.; Xie, Y. G.; Yuehong, Xie; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. N.; Zhang, Y. T.; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, Q. W.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zotti, L.; Zou, B. S.; Zou, J. H.

    2017-04-01

    We report the first measurement of the absolute branching fraction for Λc+ → Λμ+νμ. This measurement is based on a sample of e+e- annihilation data produced at a center-of-mass energy √{ s} = 4.6 GeV, collected with the BESIII detector at the BEPCII storage rings. The sample corresponds to an integrated luminosity of 567 pb-1. The branching fraction is determined to be B (Λc+ → Λμ+νμ) = (3.49 ± 0.46 (stat) ± 0.27 (syst))%. In addition, we calculate the ratio B (Λc+ → Λμ+νμ) / B (Λc+ → Λe+νe) to be 0.96 ± 0.16 (stat) ± 0.04 (syst).

  16. Absolute measurements of the high-frequency magnetic dynamics in high-{Tc} superconductors

    SciTech Connect

    Hayden, S.M.; Aeppli, G.; Dai, P.; Mook, H.A.; Perring, T.G.; Cheong, S.W.; Fisk, Z.; Dogan, F.; Mason, T.E.

    1997-08-07

    The authors review recent measurements of the high-frequency dynamic magnetic susceptibility in the high-T{sub c} superconducting systems La{sub 2{minus}x}Sr{sub x}CuO{sub 4} and YBa{sub 2}Cu{sub 3}O{sub 6+x}. Experiments were performed using the chopper spectrometers HET and MARI at the ISIS spallation source. The authors have placed their measurements on an absolute intensity scale, this allows systematic trends to be seen and comparisons with theory to be made. They find that the insulating S = 1/2 antiferromagnetic parent compounds show a dramatic renormalization in the spin wave intensity. The effect of doping on the response is to cause broadenings in wave vector and large redistributions of spectral weight in frequency.

  17. Absolute frequency measurement with uncertainty below 1× 10^{-15} using International Atomic Time

    NASA Astrophysics Data System (ADS)

    Hachisu, Hidekazu; Petit, Gérard; Ido, Tetsuya

    2017-01-01

    The absolute frequency of the ^{87}Sr clock transition measured in 2015 (Jpn J Appl Phys 54:112401, 2015) was reevaluated using an improved frequency link to the SI second. The scale interval of International Atomic Time (TAI) that we used as the reference was calibrated for an evaluation interval of 5 days instead of the conventional interval of 1 month which is regularly employed in Circular T. The calibration on a 5-day basis removed the uncertainty in assimilating the TAI scale of the 5-day mean to that of the 1-month mean. The reevaluation resulted in the total uncertainty of 10^{-16} level for the first time without local cesium fountains. Since there are presumably no correlations among systematic shifts of cesium fountains worldwide, the measurement is not limited by the systematic uncertainty of a specific primary frequency standard.

  18. The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF

    SciTech Connect

    Casey, D. T.; Frenje, J. A.; Gatu Johnson, M.; Seguin, F. H.; Li, C. K.; Petrasso, R. D.; Glebov, V. Yu.; Katz, J.; Magoon, J.; Meyerhofer, D. D.; Sangster, T. C.; Shoup, M.; Ulreich, J.; Ashabranner, R. C.; Bionta, R. M.; Carpenter, A. C.; Felker, B.; Khater, H. Y.; LePape, S.; MacKinnon, A.; McKernan, M. A.; Moran, M.; Rygg, J. R.; Yeoman, M. F.; Zacharias, R.; Leeper, R. J.; Fletcher, K.; Farrell, M.; Jasion, D.; Kilkenny, J.; Paguio, R.

    2013-04-18

    The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, iontemperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describes ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.

  19. Absolute measurement of the 242Pu neutron-capture cross section

    SciTech Connect

    Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; Bucher, B.; Chyzh, A.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Ullmann, J. L.

    2016-04-21

    Here, the absolute neutron-capture cross section of 242Pu was measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. The first direct measurement of the 242Pu(n,γ) cross section was made over the incident neutron energy range from thermal to ≈ 6 keV, and the absolute scale of the (n,γ) cross section was set according to the known 239Pu(n,f) resonance at En,R = 7.83 eV. This was accomplished by adding a small quantity of 239Pu to the 242Pu sample. The relative scale of the cross section, with a range of four orders of magnitude, was determined for incident neutron energies from thermal to ≈ 40 keV. Our data, in general, are in agreement with previous measurements and those reported in ENDF/B-VII.1; the 242Pu(n,γ) cross section at the En,R = 2.68 eV resonance is within 2.4% of the evaluated value. However, discrepancies exist at higher energies; our data are ≈30% lower than the evaluated data at En ≈ 1 keV and are approximately 2σ away from the previous measurement at En ≈ 20 keV.

  20. Designing an optical set-up of differential laser triangulation for oil film thickness measurement on water.

    PubMed

    Ge, Baozhene; Sun, Jingbin; Liu, Pengcheng; Lü, Qieni; Wu, Di

    2013-01-01

    Based on the differential laser triangulation principle, an optical system configuration for measuring the oil film thickness on water is designed and developed. A semiconductor laser of 650 nm wavelength with the maximum power of 5 mW is used as a light source, the magnification of the imaging system is 1.4; the range of the measurement is 0.1 mm-10 mm; the resolution is 2.3 μm and the measurement accuracy is 10 μm theoretically. Experiments are conducted with block gauges and feeler gauges, and the experimental results, with absolute error less than ±25 μm and the maximal measurable thickness 12 mm, indicate that this system presented in this paper can fulfill high accuracy.

  1. Measurement of absolute cell volume, osmotic membrane water permeability, and refractive index of transmembrane water and solute flux by digital holographic microscopy

    NASA Astrophysics Data System (ADS)

    Boss, Daniel; Kühn, Jonas; Jourdain, Pascal; Depeursinge, Christian; Magistretti, Pierre J.; Marquet, Pierre

    2013-03-01

    A dual-wavelength digital holographic microscope to measure absolute volume of living cells is proposed. The optical setup allows us to reconstruct two quantitative phase contrast images at two different wavelengths from a single hologram acquisition. When adding the absorbing dye fast green FCF as a dispersive agent to the extracellular medium, cellular thickness can be univocally determined in the full field of view. In addition to the absolute cell volume, the method can be applied to derive important biophysical parameters of living cells including osmotic membrane water permeability coefficient and the integral intracellular refractive index (RI). Further, the RI of transmembrane flux can be determined giving an indication about the nature of transported solutes. The proposed method is applied to cultured human embryonic kidney cells, Chinese hamster ovary cells, human red blood cells, mouse cortical astrocytes, and neurons.

  2. Thick Films acoustic sensors devoted to MTR environment measurements. Thick Films acoustic sensors devoted to Material Testing Reactor environment measurements

    SciTech Connect

    Very, F.; Rosenkrantz, E.; Combette, P.; Ferrandis, J.Y.; Fourmentel, D.; Destouches, C.; Villard, J.F.

    2015-07-01

    The development of advanced instrumentation for in-pile experiments in Material Testing Reactor constitutes a main goal for the improvement of the nuclear fuel behavior knowledge. An acoustic method for fission gas release detection was tested with success during a first experiment called REMORA 3 in 2010 and 2011, and the results were used to differentiate helium and fission gas release kinetics under transient operating conditions. This experiment was lead at OSIRIS reactor (CEA Saclay, France). The maximal temperature on the sensor during the irradiation was about 150 deg. C. In this paper we present a thick film transducer produce by screen printing process. The screen printing of piezoelectric offers a wide range of possible applications for the development of acoustic sensors and piezoelectric structure for measurements in high temperature environment. We firstly produced a Lead Zirconate Titanate (PZT) based paste composed of Pz27 powder from Ferroperm, CF7575 glass, and organic solvent ESL 400. Likewise a Bismuth Titanate based paste synthesized in our laboratory was produced. With these inks we produced thick film up to 130 μm by screen printing process. Material properties characterizations of these thick-film resonators are essential for device design and applications. The piezoelectric coefficients d33 and pyro-electric P(T) coefficient are investigated. The highest P(T) and d33 are respectively 80 μC.m{sup -2}.K{sup -1} and 130 μC.N{sup -1} for the PZT transducer -which validates the fabrication process-. In view of the development of this transducer oriented for high temperature and irradiation environment, we investigated the electrical properties of the transducers for different ranges of frequencies and temperature - from 20 Hz up to 40 MHz between 30 and 400 deg. C. We highlight the evolution of the impedance response and piezoelectric parameters of screen printed piezoelectric structures on alumina. Shortly an irradiation will be realized in

  3. Absolute and relative reliability of lumbar interspinous process ultrasound imaging measurements

    PubMed Central

    Tozawa, Ryosuke; Katoh, Munenori; Aramaki, Hidefumi; Kawasaki, Tsubasa; Nishikawa, Yuichi; Kumamoto, Tsuneo; Fujinawa, Osamu

    2016-01-01

    [Purpose] The intra- and inter-examiner reliabilities of lumbar interspinous process distances measured by ultrasound imaging were examined. [Subjects and Methods] The subjects were 10 males who had no history of orthopedic diseases or dysfunctions. Ten lumbar interspinous images from 360 images captured from 10 subjects were selected. The 10 images were measured by nine examiners. The lumbar interspinous process distance measurements were performed five times by each examiner. In addition, four of the nine examiners measured the distances again after 4 days for test-retest analysis. In statistical analysis, the intraclass correlation coefficient was used to investigate relative reliability, and Bland-Altman analysis was used to investigate absolute reliability. [Results] The intraclass correlation coefficients (1, 1) for intra-examiner reliability ranged from 0.985 to 0.998. For inter-rater reliability, the intraclass correlation coefficient (2, 1) was 0.969. The intraclass correlation coefficients (1, 2) for test-retest reliability ranged from 0.991 to 0.999. The Bland-Altman analysis results indicated no systematic error. [Conclusion] The results indicate that ultrasound measurements of interspinous process distance are highly reliable even when measured only once by a single person. PMID:27630399

  4. Absolute fluorescence measurements > 1000 nm: setup design, calibration and standards (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Resch-Genger, Ute; Würth, Christian; Pauli, Jutta; Hatami, Soheil; Kaiser, Martin

    2016-03-01

    There is an increasing interest in optical reporters like semiconductor quantum dots and upconversion nanophosphors with emission < 1000 nm for bioanalysis, medical diagnostics, and safety barcodes and hence, in reliable fluorescence measurements in this wavelength region, e.g., for the comparison of material performance and the rational design of new nanomaterials with improved properties [1-4]. The performance of fluorescence measurements < 800 nm and especially < 1000 nm is currently hampered by the lack of suitable methods and standards for the simple determination of the wavelength-dependent spectral responsivity of fluorescence measuring systems and the control of measured emission spectra and intensities [3-5]. This is of special relevance for nanocrystalline emitters like quantum dots and rods as well as for upconversion nanocrystals, where surface states and the accessibility of emissive states by quenchers largely control accomplishable quantum yields and hence, signal sizes and detection sensitivities from the reporter side. Here, we present the design of an integrating sphere setup for the absolute measurement of emission spectra and quantum yields in the wavelength region of 650 to 1600 nm and its calibration as well as examples for potential fluorescence standards from different reporter classes for the control of the reliability of such measurements [5]. This includes new spectral fluorescence standards for the wavelength region of 650 nm to 1000 nm as well as a set of quantum yield standards covering the wavelength region from 400 nm to 1000 nm.

  5. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  6. Absolute measurements of the cosmic microwave background from Amundsen-Scott South Pole Station

    SciTech Connect

    Bersanelli, S.; Bonelli, G.; Sironi, G. ); Levin, S. ); Smoot, G.F.; Bensadoun, M.; De Amici, G.; Limon, M.; Vinje, W. )

    1993-01-01

    Observations of the cosmic microwave background play a central role in modern cosmology. The existence of the CMB as a remanent of the early Universe has constituted a pillar for the Big Bang scenario. The recent cosmic background explorer differential microwave radiometer results have provided further support to the generally accepted standard model by detecting for the first time primordial fluctuations in the CMB field at the limits expected by structure formation theories. An international program of ground-based absoluted measurements of the CMB at the centimeter and multicentimeter wavelengths was initiated in 1982. This paper reports results at the South Pole, one of a few areas of low-background environments. 12 refs., 2 tabs.

  7. Measurement of the absolute reflectance of polytetrafluoroethylene (PTFE) immersed in liquid xenon

    NASA Astrophysics Data System (ADS)

    Neves, F.; Lindote, A.; Morozov, A.; Solovov, V.; Silva, C.; Bras, P.; Rodrigues, J. P.; Lopes, M. I.

    2017-01-01

    The performance of a detector using liquid xenon (LXe) as a scintillator is strongly dependent on the collection efficiency for xenon scintillation light, which in turn is critically dependent on the reflectance of the surfaces that surround the active volume. To improve the light collection in such detectors the active volume is usually surrounded by polytetrafluoroethylene (PTFE) reflector panels, used due to its very high reflectance—even at the short wavelength of scintillation light of LXe (peaked at 178 nm). In this work, which contributed to the overall R&D effort towards the LUX-ZEPLIN (LZ) experiment, we present experimental results for the absolute reflectance measurements of three different PTFE samples (including the material used in the LUX detector) immersed in LXe for its scintillation light. The obtained results show that very high bi-hemispherical reflectance values (>= 97%) can be achieved, enabling very low energy thresholds in liquid xenon scintillator-based detectors.

  8. Absolute spectral response measurements of different photodiodes useful for applications in the UV spectral region

    NASA Astrophysics Data System (ADS)

    Pelizzo, Maria G.; Ceccherini, Paolo; Garoli, Denis; Masut, Pietro; Nicolosi, Piergiorgio

    2004-09-01

    Long UV radiation exposure can result in damages of biological tissues, as burns, skin aging, erythema and even melanoma cancer. In the past years an increase of melanoma cancer has been observed and associated to the atmospheric ozone deployment. Attendance of sun tanning unit centers has become a huge social phenomena, and the maximum UV radiation dose that a human being can receive is regulated by law. On the other side, UV radiation is largely used for therapeutic and germicidal purposes. In all these areas, spectroradiometer and radiomenter are needed for monitoring UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm) irradiance. We have selected some commercial photodiodes which can be used as solid state detectors in these instruments. We have characterized them by measuring their absolute spectral response in the 200 - 400 nm spectral range.

  9. Measurement of the Absolute Branching Fraction of D0 to K- pi+

    SciTech Connect

    Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prudent, X.; Tisserand, V.; Zghiche, A.; Garra Tico, J.; Grauges, E.; Lopez, L.; Palano, A.; Eigen, G.; Ofte, I.; Stugu, B.; Sun, L.; Abrams, G.S.; Battaglia, M.; Brown, D.N.; Button-Shafer, J.; /LBL, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Munich, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /Frascati /Genoa U. /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Karlsruhe U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Maryland U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /Paris U., VI-VII /Pennsylvania U. /Perugia U. /Pisa U. /Prairie View A-M /Princeton U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U.

    2007-04-25

    The authors measure the absolute branching fraction for D{sup 0} {yields} K{sup -} {pi}{sup +} using partial reconstruction of {bar B}{sup 0} {yields} D*{sup +}X{ell}{sup -}{bar {nu}}{sub {ell}} decays, in which only the charged lepton and the pion from the decay D*{sup +} {yields} D{sup 0}{pi}{sup +} are used. Based on a data sample of 230 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, they obtain {Beta}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = (4.007 {+-} 0.037 {+-} 0.070)%, where the first error is statistical and the second error is systematic.

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

    NASA Astrophysics Data System (ADS)

    Ren, Hongyu; Jiang, Xiangqian; Gao, Feng; Zhang, Zonghua

    2014-07-01

    Deflectometric methods have been studied for more than a decade for slope measurement of specular freeform surfaces through utilization of the deformation of a sample pattern after reflection from a tested sample surface. Usually, these approaches require two-directional fringe patterns to be projected on a LCD screen or ground glass and require slope integration, which leads to some complexity for the whole measuring process. This paper proposes a new mathematical measurement model for measuring topography information of freeform specular surfaces, which integrates a virtual reference specular surface into the method of active fringe reflection photogrammetry and presents a straight-forward relation between height of the tested surface and phase signals. This method only requires one direction of horizontal or vertical sinusoidal fringe patterns to be projected from a LCD screen, resulting in a significant reduction in capture time over established methods. Assuming the whole system has been precalibrated during the measurement process, the fringe patterns are captured separately via the virtual reference and detected freeform surfaces by a CCD camera. The reference phase can be solved according to the spatial geometric relation between the LCD screen and the CCD camera. The captured phases can be unwrapped with a heterodyne technique and optimum frequency selection method. Based on this calculated unwrapped-phase and that proposed mathematical model, absolute height of the inspected surface can be computed. Simulated and experimental results show that this methodology can conveniently calculate topography information for freeform and structured specular surfaces without integration and reconstruction processes.

  11. Absolute Calibration of the Magnetic Field Measurement for Muon g-2

    NASA Astrophysics Data System (ADS)

    Farooq, Midhat; Chupp, Tim; Muon g-2 Collaboration Collaboration

    2017-01-01

    The muon g-2 experiment at Fermilab (E989) investigates the >3- σ discrepancy between the standard model prediction and the current experimental measurement of the muon magnetic moment anomaly, aμ = (g-2)/2. The effort requires a precise measurement of the 1.45 T magnetic field of the muon storage ring to 70 ppb. The final measurement will employ multiple absolute calibration probes: two water probes and a 3He probe. The 3He probe offers a cross-check of the water probes with different systematic corrections, adding a level of confidence to the measurement. A low-field 3He probe was developed at the Univ. of Michigan by employing a method called MEOP for the hyper-polarization of 3He gas, followed by NMR to determine the frequency proportional to the magnetic field in which the probe is placed. A modified probe design for operation under high fields will be tested at Argonne National Lab. Future development also involves the study of the systematic uncertainties to attain the error budget of <30 ppb for the calibration. Next, the calibration from the probes will be transferred to g-2 through several steps of a calibration chain ending in the final step of calibrating the NMR probes which measure the field in the muon storage ring at Fermilab. NSF PHY-1506021.

  12. Is absolute noninvasive temperature measurement by the Pr[MOE-DO3A] complex feasible.

    PubMed

    Hentschel, M; Findeisen, M; Schmidt, W; Frenzel, T; Wlodarczyk, W; Wust, P; Felix, R

    2000-02-01

    Recently, the feasibility of the praseodymium complex of 10-(2-methoxyethyl)-1,4,7,10-tetraaza-cyclododecane-1,4,7-tr iacetate (Pr[MOE-DO3A]) for non-invasive temperature measurement via 1H spectroscopy has been demonstrated. Particularly the suitability of the complex for non-invasive temperature measurements including in vivo spectroscopy without spatial resolution as well as first spectroscopic imaging measurements at low temporal resolution (> or = 4 min) and high temporal resolution (breath hold, approximately 20 s) has been shown. As of today, calibration curves according to the particular experimental conditions are necessary. This work aims to clarify whether the Pr[MOE-DO3A] probe in conjunction with 1H-NMR spectroscopy allows non-invasive absolute temperature measurements with high accuracy. The measurement results from two different representative media, distilled water and human plasma, show a slight but significant dependence of the calibration curves on the surrounding medium. Calibration curves in water and plasma were derived for the temperature dependence of the chemical shift difference (F) between Pr[MOE-DO3A]'s OCH3 and water with F = -(27.53 +/- 0.04) + (0.125 +/- 0.001) x T and F = -(27.61 +/- 0.02) + (0.129 +/- 0.001) x T, respectively, with F in ppm and T in degrees C. However, the differences are minuscule even for the highest spectral resolution of 0.001 ppm/pt, so that they are indistinguishable under practical conditions. The estimated temperature errors are +/- 0.18 degrees C for water and +/- 0.14 degrees C for plasma and with that only slightly worse than the measurement accuracy of the fiber-optical temperature probe (+/- 0.1 degrees C). It can be concluded that the results obtained indicate the feasibility of the 1H spectroscopy method in conjunction with the Pr[MOE-DO3A] probe for absolute temperature measurements, with a maximum accuracy of +/- 0.2 degrees C.

  13. Demonstrating the error budget for the climate absolute radiance and refractivity observatory through solar irradiance measurements (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Thome, Kurtis J.; McCorkel, Joel; Angal, Amit

    2016-09-01

    The goal of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is to provide high-accuracy data for evaluation of long-term climate change trends. Essential to the CLARREO project is demonstration of SI-traceable, reflected measurements that are a factor of 10 more accurate than current state-of-the-art sensors. The CLARREO approach relies on accurate, monochromatic absolute radiance calibration in the laboratory transferred to orbit via solar irradiance knowledge. The current work describes the results of field measurements with the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) that is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. Recent measurements of absolute spectral solar irradiance using SOLARIS are presented. The ground-based SOLARIS data are corrected to top-of-atmosphere values using AERONET data collected within 5 km of the SOLARIS operation. The SOLARIS data are converted to absolute irradiance using laboratory calibrations based on the Goddard Laser for Absolute Measurement of Radiance (GLAMR). Results are compared to accepted solar irradiance models to demonstrate accuracy values giving confidence in the error budget for the CLARREO reflectance retrieval.

  14. An absolute index (Ab-index) to measure a researcher's useful contributions and productivity.

    PubMed

    Biswal, Akshaya Kumar

    2013-01-01

    Bibliographic analysis has been a very powerful tool in evaluating the effective contributions of a researcher and determining his/her future research potential. The lack of an absolute quantification of the author's scientific contributions by the existing measurement system hampers the decision-making process. In this paper, a new metric system, Absolute index (Ab-index), has been proposed that allows a more objective comparison of the contributions of a researcher. The Ab-index takes into account the impact of research findings while keeping in mind the physical and intellectual contributions of the author(s) in accomplishing the task. The Ab-index and h-index were calculated for 10 highly cited geneticists and molecular biologist and 10 young researchers of biological sciences and compared for their relationship to the researchers input as a primary author. This is the first report of a measuring method clarifying the contributions of the first author, corresponding author, and other co-authors and the sharing of credit in a logical ratio. A java application has been developed for the easy calculation of the Ab-index. It can be used as a yardstick for comparing the credibility of different scientists competing for the same resources while the Productivity index (Pr-index), which is the rate of change in the Ab-index per year, can be used for comparing scientists of different age groups. The Ab-index has clear advantage over other popular metric systems in comparing scientific credibility of young scientists. The sum of the Ab-indices earned by individual researchers of an institute per year can be referred to as Pr-index of the institute.

  15. Absolute branching fraction measurements for exclusive D{sub s} semileptonic decays

    SciTech Connect

    Yelton, J.; Rubin, P.; Lowrey, N.; Mehrabyan, S.; Selen, M.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.; Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Poling, R.; Scott, A. W.; Zweber, P.; Dobbs, S.; Metreveli, Z.

    2009-09-01

    We measure the absolute branching fractions of D{sub s} semileptonic decays where the hadron in the final state is one of {phi}, {eta}, {eta}{sup '}, K{sub S}{sup 0}, K*{sup 0}, and f{sub 0}, using 2.8x10{sup 5} e{sup +}e{sup -}{yields}D{sub s}D{sub s}* decays collected in the CLEO-c detector at a center-of-mass energy close to 4170 MeV. We obtain B(D{sub s}{sup +}{yields}{phi}e{sup +}{nu}{sub e})=(2.29{+-}0.37{+-}0.11)%, B(D{sub s}{sup +}{yields}{eta}e{sup +}{nu}{sub e})=(2.48{+-}0.29{+-}0.13)%, B(D{sub s}{sup +}{yields}{eta}{sup '}e{sup +}{nu}{sub e})=(0.91{+-}0.33{+-}0.05)%, where the first uncertainties are statistical and the second are systematic. We also obtain B(D{sub s}{sup +}{yields}K{sup 0}e{sup +}{nu}{sub e})=(0.37{+-}0.10{+-}0.02)%, and B(D{sub s}{sup +}{yields}K*{sup 0}e{sup +}{nu}{sub e})=(0.18{+-}0.07{+-}0.01)%, which are the first measurements of Cabibbo suppressed exclusive D{sub s} semileptonic decays, and, B(D{sub s}{sup +}{yields}f{sub 0}e{sup +}{nu}{sub e})xB(f{sub 0}{yields}{pi}{sup +}{pi}{sup -})=(0.13{+-}0.04{+-}0.01)%. This is the first absolute product branching fraction determination for a semileptonic decay including a scalar meson in the final state.

  16. Method for improving terahertz band absorption spectrum measurement accuracy using noncontact sample thickness measurement.

    PubMed

    Li, Zhi; Zhang, Zhaohui; Zhao, Xiaoyan; Su, Haixia; Yan, Fang; Zhang, Han

    2012-07-10

    The terahertz absorption spectrum has a complex nonlinear relationship with sample thickness, which is normally measured mechanically with limited accuracy. As a result, the terahertz absorption spectrum is usually determined incorrectly. In this paper, an iterative algorithm is proposed to accurately determine sample thickness. This algorithm is independent of the initial value used and results in convergent calculations. Precision in sample thickness can be improved up to 0.1 μm. A more precise absorption spectrum can then be extracted. By comparing the proposed method with the traditional method based on mechanical thickness measurements, quantitative analysis experiments on a three-component amino acid mixture shows that the global error decreased from 0.0338 to 0.0301.

  17. Measurements of Absolute Hadronic Branching Fractions of the Λc+ Baryon

    NASA Astrophysics Data System (ADS)

    Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, H. Y.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, X.; Chen, X. R.; Chen, Y. B.; Cheng, H. P.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; de Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Eren, E. E.; Fan, J. Z.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Farinelli, R.; Fava, L.; Fedorov, O.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, X. Y.; Gao, Y.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y.; Guo, Y. P.; Haddadi, Z.; Hafner, A.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, Y.; Hussain, T.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, L. W.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Kiese, P.; Kliemt, R.; Kloss, B.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuehn, W.; Kupsc, A.; Lange, J. S.; Lara, M.; Larin, P.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, Lei; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. M.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Loehner, H.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Messchendorp, J. G.; Min, J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, L. Q.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Ripka, M.; Rong, G.; Rosner, Ch.; Ruan, X. D.; Santoro, V.; Sarantsev, A.; Savrié, M.; Schoenning, K.; Schumann, S.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Song, W. M.; Song, X. Y.; Sosio, S.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Tiemens, M.; Ullrich, M.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, S. G.; Wang, W.; Wang, W. P.; Wang, X. F.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Weber, T.; Wei, D. H.; Wei, J. B.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, Z.; Xia, L.; Xia, L. G.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J. J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. N.; Zhang, Y. T.; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, Q. W.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zotti, L.; Zou, B. S.; Zou, J. H.; Besiii Collaboration

    2016-02-01

    We report the first measurement of absolute hadronic branching fractions of Λc+ baryon at the Λc+Λ¯c - production threshold, in the 30 years since the Λc+ discovery. In total, 12 Cabibbo-favored Λc+ hadronic decay modes are analyzed with a double-tag technique, based on a sample of 567 pb-1 of e+e- collisions at √{s }=4.599 GeV recorded with the BESIII detector. A global least-squares fitter is utilized to improve the measured precision. Among the measurements for twelve Λc+ decay modes, the branching fraction for Λc+→p K-π+ is determined to be (5.84 ±0.27 ±0.23 )%, where the first uncertainty is statistical and the second is systematic. In addition, the measurements of the branching fractions of the other 11 Cabibbo-favored hadronic decay modes are significantly improved.

  18. Absolute air refractive index measurement and tracking based on variable length vacuum cell

    NASA Astrophysics Data System (ADS)

    Yu, Xiangzhi; Zhang, Tieli; Ellis, Jonathan D.

    2016-06-01

    A refractometer system using four modified Wu-type heterodyne interferometers with a variable length vacuum cell is presented. The proposed system has two working modes: (1) a moving mode for measuring the absolute air refractive index at the start of a measurement and (2) a static mode for monitoring the air refractive index fluctuation with the same bandwidth as a traditional displacement interferometer. The system requires no gas filling or pumping during the measurement and can be used for real-time refractive index compensation. Comparison experiments with empirical equations are conducted to investigate the feasibility and performance of the proposed system. The standard deviation of the measurement difference between the proposed system and empirical equation is 2.8 parts in 107, which is close to the uncertainty of our refractive index reference based on the accuracy of the environmental sensors. The relative refractive index tracking is a few parts in 108 with a bandwidth of 10 Hz, but high bandwidths are readily achievable.

  19. Characteristic Functional of a Probability Measure Absolutely Continuous with Respect to a Gaussian Radon Measure

    DTIC Science & Technology

    1984-08-01

    1962) 372-390. 5. J. Neveu, "Martingales a temps discret." Masson et Cie. Paris. 1972. 6. H. Sato and Y. Okazaki, Separabilities of a Gaussian Radon measure. Ann. Inst. Henri Poincare , 11 (1975) 287-298.

  20. The impact of water temperature on the measurement of absolute dose

    NASA Astrophysics Data System (ADS)

    Islam, Naveed Mehdi

    To standardize reference dosimetry in radiation therapy, Task Group 51 (TG 51) of American Association of Physicist's in Medicine (AAPM) recommends that dose calibration measurements be made in a water tank at a depth of 10 cm and at a reference geometry. Methodologies are provided for calculating various correction factors to be applied in calculating the absolute dose. However the protocol does not specify the water temperature to be used. In practice, the temperature of water during dosimetry may vary considerably between independent sessions and different centers. In this work the effect of water temperature on absolute dosimetry has been investigated. Density of water varies with temperature, which in turn may impact the beam attenuation and scatter properties. Furthermore, due to thermal expansion or contraction air volume inside the chamber may change. All of these effects can result in a change in the measurement. Dosimetric measurements were made using a Farmer type ion chamber on a Varian Linear Accelerator for 6 MV and 23 MV photon energies for temperatures ranging from 10 to 40 °C. A thermal insulation was designed for the water tank in order to maintain relatively stable temperature over the duration of the experiment. Dose measured at higher temperatures were found to be consistently higher by a very small magnitude. Although the differences in dose were less than the uncertainty in each measurement, a linear regression of the data suggests that the trend is statistically significant with p-values of 0.002 and 0.013 for 6 and 23 MV beams respectively. For a 10 degree difference in water phantom temperatures, which is a realistic deviation across clinics, the final calculated reference dose can differ by 0.24% or more. To address this effect, first a reference temperature (e.g.22 °C) can be set as the standard; subsequently a correction factor can be implemented for deviations from this reference. Such a correction factor is expected to be of similar

  1. Reservoir properties inversion in a karst aquifer using absolute gravity measurements

    NASA Astrophysics Data System (ADS)

    Sabrina, Deville; Thomas, Jacob; Jean, Chery; Roger, Bayer; Cedric, Champollion; Moigne Nicolas, Le

    2010-05-01

    Direct estimate of water storage and transfer in karst aquifers are difficult to obtain due to the extreme permeability variation of the medium. In this study, we aim to quantify water transfer properties in a karst aquifer of the Larzac plateau (South Massif Central, France) using absolute gravity monitoring. Our measurements are cutting edge as they directly measure the integrated water content below the gravimeter. We analyze monthly repeated FG5 absolute gravity measurements (1-2 microGal precision) over a three-year period at three sites on the karst aquifer. Important precipitation events lead to significant gravity increases which peak up to several weeks after the events depending on the site. Also, gravity decreases in a different manner at each site during drier periods. We consider the different gravity responses at each site to relate to water transfer properties between the surface and the unsaturated zone beneath. Within this scope, the gravity signal is used to invert for those water transfer properties. A simple two-tank reservoir model including a ‘soil' reservoir that feeds into a ‘subsurface' reservoir is used as the forward model in a Monte Carlo simulation. Reservoir discharge proceeds according to Maillet's law. Water levels within the reservoirs are converted into a gravity signal considering an infinite slab scaled by a factor that accounts for both the surrounding topographic effects and the water interception by the building where the measurements are made. Inverted parameters are the discharge constants and the scaling factors. Model input is rainfall measured with rain gauges at each site minus estimated evapotranspiration. The inversion leads to scaling factors much smaller than 1 for the attraction of the surface reservoir. The effects of the surrounding topography and those of the building on gravity are compared to the inversion result of the ‘surface reservoir' scaling factors. We discuss if the forward model and underlying

  2. Thickness and air gap measurement of assembled IR objectives

    NASA Astrophysics Data System (ADS)

    Lueerss, B.; Langehanenberg, P.

    2015-05-01

    A growing number of applications like surveillance, thermography, or automotive demand for infrared imaging systems. Their imaging performance is significantly influenced by the alignment of the individual lens elements. Besides the lateral orientation of lenses, the air spacing between the lenses is a crucial parameter. Because of restricted mechanical accessibility within an assembled objective, a non-contact technique is required for the testing of these parameters. So far commercial measurement systems were not available for testing of IR objectives since many materials used for infrared imaging are non-transparent at wavelengths below 2 μm. We herewith present a time-domain low coherent interferometer capable of measuring any kind of infrared material (e.g., Ge, Si, etc.) as well as VIS materials. The fiber-optic set-up is based on a Michelson-Interferometer in which the light from a broadband super-luminescent diode is split into a reference arm with a variable optical delay and a measurement arm where the sample is placed. On a photo detector, the reflected signals from both arms are superimposed and recorded as a function of the variable optical path. Whenever the group delay difference is zero, a coherence peak occurs and the relative lens' surface distances are derived from the optical delay. In order to penetrate IR materials, the instrument operates at 2.2 μm. The set-up allows the contactless determination of thicknesses and air gaps inside of assembled infrared objective lenses with accuracy in the micron range. It therefore is a tool for the precise manufacturing or quality control.

  3. Approximation by Absolutely Continuous Invariant Measures of Iterated Function Systems with Place-Dependent Probabilities

    NASA Astrophysics Data System (ADS)

    Islam, Md Shafiqul; Chandler, Stephen

    2015-10-01

    Let S be the attractor (fractal) of a contractive iterated function system (IFS) with place-dependent probabilities. An IFS with place-dependent probabilities is a random map T = {τ1(x),τ2(x),…,τK(x); p1(x),p2(x),…,pK(x)}, where the probabilities p1(x),p2(x),…,pK(x) of switching from one transformation to another are functions of positions, that is, at each step, the random map T moves the point x to τk(x) with probability pk(x). If the random map T has a unique invariant measure μ, then the support of μ is the attractor S. For a bounded region X ⊆ ℝN, we prove the existence of a sequence {T0,n∗} of IFSs with place-dependent probabilities whose invariant measures {μn} are absolutely continuous with respect to Lebesgue measure. Moreover, if X is a compact metric space, we prove that μn converges weakly to μ as n →∞. We present examples with computations.

  4. Femtosecond frequency comb measurement of absolute frequencies and hyperfine coupling constants in cesium vapor

    SciTech Connect

    Stalnaker, Jason E.; Mbele, Vela; Gerginov, Vladislav; Fortier, Tara M.; Diddams, Scott A.; Hollberg, Leo; Tanner, Carol E.

    2010-04-15

    We report measurements of absolute transition frequencies and hyperfine coupling constants for the 8S{sub 1/2}, 9S{sub 1/2}, 7D{sub 3/2}, and 7D{sub 5/2} states in {sup 133}Cs vapor. The stepwise excitation through either the 6P{sub 1/2} or 6P{sub 3/2} intermediate state is performed directly with broadband laser light from a stabilized femtosecond laser optical-frequency comb. The laser beam is split, counterpropagated, and focused into a room-temperature Cs vapor cell. The repetition rate of the frequency comb is scanned and we detect the fluorescence on the 7P{sub 1/2,3/2{yields}}6S{sub 1/2} branches of the decay of the excited states. The excitations to the different states are isolated by the introduction of narrow-bandwidth interference filters in the laser beam paths. Using a nonlinear least-squares method we find measurements of transition frequencies and hyperfine coupling constants that are in agreement with other recent measurements for the 8S state and provide improvement by 2 orders of magnitude over previously published results for the 9S and 7D states.

  5. Measurements of absolute radical densities in atmospheric pressure plasmas with complex gas mixtures

    NASA Astrophysics Data System (ADS)

    O'Connell, Deborah

    2015-05-01

    Low temperature plasmas are emerging as an exciting development for therapeutics. Non-equilibrium plasmas, operated at ambient atmospheric pressure and temperature, are very efficient sources for highly reactive neutral particles, including reactive oxygen and nitrogen species (RONS), which are known to play a crucial role in biological systems and existing therapeutics. Transport of these plasma components to the target is complex. In order to understand the chemical kinetics and plasma-liquid-biological interaction mechanisms measurements of the relevant RONS are key. Under atmospheric pressure these are challenging, primarily due to the multi-phase and highly collisional environment, requiring extremely high temporal (picosecond to nanosecond) and spatial (microns) resolution. Absolute measurements of radical densities (including O and OH) using picosecond two-photon absorption laser induced fluorescence (ps-TALIF), UV and high-resolution synchrotron VUV absorption spectroscopy will be presented. Fluorescence lifetime measurements of the laser-excited radicals are possible with picosecond resolution and this provides us with information about collisional quenching partners and thus collision kinetics with the surrounding environment. The authors acknowledge support by the UK EPSRC EP/H003797 and EP/K018388.

  6. Absolute angle measurement using the earth-field-referenced hall effect sensors.

    PubMed

    Kolen, P T; Rhode, J P; Francis, P R

    1993-03-01

    A miniaturized absolute angle sensor utilizing Hall generators referenced to the Earth's ambient magnetic field has been developed. The sensor has three-dimensional angular sensitivity which allows the output to be self-normalized resulting in high immunity to both B-field and temperature induced errors. The individual Hall generator elements were operated with a final sensitivity of 4.07 V G-1. The Earth's field, magnitude 0.486 G with a surface declination angle of 58.2 degrees (San Diego, California), was used as the excitation/reference field. Bandwidth limiting, low-noise design, and active/passive thermal compensation techniques were employed resulting in a sensor bandwidth of DC to 100 Hz with a maximum signal-to-noise ratio of 44.5 dB. The maximum angular resolution of the sensor was measured to be +/- 0.27 degrees. Temperature induced error was measured to be less than 2% from 25 degrees C to 40 degrees C. The measurement of shoulder joint rotation was used as the test case application for the sensor with excellent agreement between theoretical and experimental performance.

  7. Rotary union for use with ultrasonic thickness measuring probe

    DOEpatents

    Nachbar, H.D.

    1992-09-15

    A rotary union for rotatably supporting an ultrasonic probe operable to nondestructively measure the thickness of steam generator tubes to determine the amount of corrosion experienced by the tubes includes a stationary body having a bore therethrough and an outlet drain, and a fitting rotatably mounted within the upper end of the body. The fitting has a bore aligned with the bore of the body. An electrical cable positioned within a water supply tube in an annular arrangement passes through the bore of the body and the bore of the fitting. This annular arrangement, in turn, is positioned within a connector element which extends outwardly from the fitting bore and is connected to the ultrasonic probe. An elastomeric lower bushing seals the annular arrangement to the lower end of the rotary union body and an elastomeric upper bushing seals the connector element to the fitting to permit the connector element and the ultrasonic probe connected thereto to rotate with the fitting relative to the body. The lower and upper bushings permit water to be passed through the annular arrangement and into the ultrasonic probe and thereafter discharged between the annular arrangement and the connector element to the outlet drain of the rotary union body. 5 figs.

  8. Rotary union for use with ultrasonic thickness measuring probe

    DOEpatents

    Nachbar, Henry D.

    1992-01-01

    A rotary union for rotatably supporting an ultrasonic probe operable to nondestructively measure the thickness of steam generator tubes to determine the amount of corrosion experienced by the tubes includes a stationary body having a bore therethrough and an outlet drain, and a fitting rotatably mounted within the upper end of the body. The fitting has a bore aligned with the bore of the body. An electrical cable positioned within a water supply tube in an annular arrangement passes through the bore of the body and the bore of the fitting. This annular arrangement, in turn, is positioned within a connector element which extends outwardly from the fitting bore and is connected to the ultrasonic probe. An elastomeric lower bushing seals the annular arrangement to the lower end of the rotary union body and an elastomeric upper bushing seals the connector element to the fitting to permit the connector element and the ultrasonic probe connected thereto to rotate with the fitting relative to the body. The lower and upper bushings permit water to be passed through the annular arrangement and into the ultrasonic probe and thereafter discharged between the annular arrangement and the connector element to the outlet drain of the rotary union body.

  9. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    SciTech Connect

    Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; /more authors..

    2012-09-20

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

  10. Measurement of the Absolute Branching Fractions for $D^-_s\\!\\rightarrow\\!\\ell^-\\bar{\

    SciTech Connect

    del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, David Nathan; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /more authors..

    2010-10-27

    The absolute branching fractions for the decays D{sub s}{sup -} {yields} {ell}{sup -}{bar {nu}}{sub {ell}} ({ell} = e, {mu}, or {tau}) are measured using a data sample corresponding to an integrated luminosity of 521 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. The number of D{sub s}{sup -} mesons is determined by reconstructing the recoiling system DKX{gamma} in events of the type e{sup +}e{sup -}DKXD*{sub s}{sup -}, where D*{sub s}{sup -} {yields} D{sub s}{sup -}{gamma} and X represents additional pions from fragmentation. The D{sub s}{sup -} {yields} {ell}{sup 0}{nu}{sub {ell}} events are detected by full or partial reconstruction of the recoiling system DKX{gamma}{ell}. The branching fraction measurements are combined to determine the D{sub s}{sup -} decay constant f{sub D{sub s}} = (258.6 {+-} 6.4 {+-} 7.5) MeV, where the first uncertainty is statistical and the second is systematic.

  11. Absolute calibration of the OMEGA streaked optical pyrometer for temperature measurements of compressed materials

    DOE PAGES

    Gregor, M. C.; Boni, R.; Sorce, A.; ...

    2016-11-29

    Experiments in high-energy-density physics often use optical pyrometry to determine temperatures of dynamically compressed materials. In combination with simultaneous shock-velocity and optical-reflectivity measurements using velocity interferometry, these experiments provide accurate equation-of-state data at extreme pressures (P > 1 Mbar) and temperatures (T > 0.5 eV). This paper reports on the absolute calibration of the streaked optical pyrometer (SOP) at the Omega Laser Facility. The wavelength-dependent system response was determined by measuring the optical emission from a National Institute of Standards and Technology–traceable tungsten-filament lamp through various narrowband (40 nm-wide) filters. The integrated signal over the SOP’s ~250-nm operating range ismore » then related to that of a blackbody radiator using the calibrated response. We present a simple closed-form equation for the brightness temperature as a function of streak-camera signal derived from this calibration. As a result, error estimates indicate that brightness temperature can be inferred to a precision of <5%.« less

  12. Absolute calibration of the OMEGA streaked optical pyrometer for temperature measurements of compressed materials

    NASA Astrophysics Data System (ADS)

    Gregor, M. C.; Boni, R.; Sorce, A.; Kendrick, J.; McCoy, C. A.; Polsin, D. N.; Boehly, T. R.; Celliers, P. M.; Collins, G. W.; Fratanduono, D. E.; Eggert, J. H.; Millot, M.

    2016-11-01

    Experiments in high-energy-density physics often use optical pyrometry to determine temperatures of dynamically compressed materials. In combination with simultaneous shock-velocity and optical-reflectivity measurements using velocity interferometry, these experiments provide accurate equation-of-state data at extreme pressures (P > 1 Mbar) and temperatures (T > 0.5 eV). This paper reports on the absolute calibration of the streaked optical pyrometer (SOP) at the Omega Laser Facility. The wavelength-dependent system response was determined by measuring the optical emission from a National Institute of Standards and Technology-traceable tungsten-filament lamp through various narrowband (40-nm-wide) filters. The integrated signal over the SOP's ˜250-nm operating range is then related to that of a blackbody radiator using the calibrated response. We present a simple closed-form equation for the brightness temperature as a function of streak-camera signal derived from this calibration. Error estimates indicate that brightness temperature can be inferred to a precision of <5%.

  13. Absolute calibration of the OMEGA streaked optical pyrometer for temperature measurements of compressed materials

    SciTech Connect

    Gregor, M. C.; Boni, R.; Sorce, A.; Kendrick, J.; McCoy, C. A.; Polsin, D. N.; Boehly, T. R.; Celliers, P. M.; Collins, G. W.; Fratanduono, D. E.; Eggert, J. H.; Millot, M.

    2016-11-29

    Experiments in high-energy-density physics often use optical pyrometry to determine temperatures of dynamically compressed materials. In combination with simultaneous shock-velocity and optical-reflectivity measurements using velocity interferometry, these experiments provide accurate equation-of-state data at extreme pressures (P > 1 Mbar) and temperatures (T > 0.5 eV). This paper reports on the absolute calibration of the streaked optical pyrometer (SOP) at the Omega Laser Facility. The wavelength-dependent system response was determined by measuring the optical emission from a National Institute of Standards and Technology–traceable tungsten-filament lamp through various narrowband (40 nm-wide) filters. The integrated signal over the SOP’s ~250-nm operating range is then related to that of a blackbody radiator using the calibrated response. We present a simple closed-form equation for the brightness temperature as a function of streak-camera signal derived from this calibration. As a result, error estimates indicate that brightness temperature can be inferred to a precision of <5%.

  14. ArtDeco: a beam-deconvolution code for absolute cosmic microwave background measurements

    NASA Astrophysics Data System (ADS)

    Keihänen, E.; Reinecke, M.

    2012-12-01

    We present a method for beam-deconvolving cosmic microwave background (CMB) anisotropy measurements. The code takes as input the time-ordered data along with the corresponding detector pointings and known beam shapes, and produces as output the harmonic aTlm, aElm, and aBlm coefficients of the observed sky. From these one can derive temperature and Q and U polarisation maps. The method is applicable to absolute CMB measurements with wide sky coverage, and is independent of the scanning strategy. We tested the code with extensive simulations, mimicking the resolution and data volume of Planck 30 GHz and 70 GHz channels, but with exaggerated beam asymmetry. We applied it to multipoles up to l = 1700 and examined the results in both pixel space and harmonic space. We also tested the method in presence of white noise. The code is released under the terms of the GNU General Public License and can be obtained from http://sourceforge.net/projects/art-deco/

  15. Superheterodyne configuration for two-wavelength interferometry applied to absolute distance measurement.

    PubMed

    Le Floch, Sébastien; Salvadé, Yves; Droz, Nathalie; Mitouassiwou, Rostand; Favre, Patrick

    2010-02-01

    We present a new superheterodyne technique for long-distance measurements by two-wavelength interferometry (TWI). While conventional systems use two acousto-optic modulators to generate two different heterodyne frequencies, here the two frequencies result from synchronized sweeps of optical and radio frequencies. A distributed feedback laser source is injected in an intensity modulator that is driven at the half-wave voltage mode. A radio-frequency signal is applied to this intensity modulator to generate two optical sidebands around the optical carrier. This applied radio frequency consists of a digital ramp between 13 and 15 GHz, with 1 ms duration and with an accuracy of better than 1 ppm. Simultaneously, the laser source is frequency modulated by a current modulation that is synchronized on the radio-frequency ramp as well as on a triangle waveform. These two frequency-swept optical signals at the output of the modulator illuminate a Michelson interferometer and create two distinct distance-dependent heterodyne frequencies on the photodetector. The superheterodyne signal is then detected and bandpass filtered to retrieve the absolute distance measurement. Experiments between 1 and 15 m confirm the validity of this new concept, leading to a distance accuracy of +/- 50 microm for a 1 ms acquisition time.

  16. Superheterodyne configuration for two-wavelength interferometry applied to absolute distance measurement

    SciTech Connect

    Le Floch, Sebastien; Salvade, Yves; Droz, Nathalie; Mitouassiwou, Rostand; Favre, Patrick

    2010-02-01

    We present a new superheterodyne technique for long-distance measurements by two-wavelength interferometry (TWI). While conventional systems use two acousto-optic modulators to generate two different heterodyne frequencies, here the two frequencies result from synchronized sweeps of optical and radio frequencies. A distributed feedback laser source is injected in an intensity modulator that is driven at the half-wave voltage mode. A radio-frequency signal is applied to this intensity modulator to generate two optical sidebands around the optical carrier. This applied radio frequency consists of a digital ramp between 13 and 15 GHz, with 1 ms duration and with an accuracy of better than 1 ppm. Simultaneously, the laser source is frequency modulated by a current modulation that is synchronized on the radio-frequency ramp as well as on a triangle waveform. These two frequency-swept optical signals at the output of the modulator illuminate a Michelson interferometer and create two distinct distance-dependent heterodyne frequencies on the photodetector. The superheterodyne signal is then detected and bandpass filtered to retrieve the absolute distance measurement. Experiments between 1 and 15 m confirm the validity of this new concept, leading to a distance accuracy of {+-} 50 {mu}m for a 1 ms acquisition time.

  17. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Barbielini, G; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B,; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Gehrels, N.; Hays, E.; McEnery, J. E.; Thompson, D. J.; Troja, E. J.

    2012-01-01

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron- plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between approx. 6 and approx. 13 GeV with an estimated uncertainty of approx. 2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

  18. Measuring the absolute water content of the brain using quantitative MRI.

    PubMed

    Shah, Nadim Joni; Ermer, Veronika; Oros-Peusquens, Ana-Maria

    2011-01-01

    Methods for quantitative imaging of the brain are presented and compared. Highly precise and accurate mapping of the absolute water content and distribution, as presented here, requires a significant number of corrections and also involves mapping of other MR parameters. Here, either T(1) and T(2)(*) or T(2) is mapped, and several corrections involving the measurement of temperature, transmit and receive B(1) inhomogeneities and signal extrapolation to zero TE are applied. Information about the water content of the whole brain can be acquired in clinically acceptable measurement times (10 or 20 min). Since water content is highly regulated in the healthy brain, pathological changes can be easily identified and their evolution or correlation with other manifestations of the disease investigated. In addition to voxel-based total water content, information about the different environments of water can be gleaned from qMRI. The myelin water fraction can be extracted from the fit of very high-SNR multiple-echo T(2) decay curves with a superposition of a large number of exponentials. Diseases involving de- or dysmyelination can be investigated and lead to novel observations regarding the water compartmentalisation in tissue, despite the limited spatial coverage. In conclusion, quantitative MRI is emerging as an unparalleled tool for the study of the normal and diseased brain, replacing the customary time-space environment of the sequential mixed-contrast MRI with a multi-NMR-parametric space in which tissue microscopy is increasingly revealed.

  19. Measuring U-Series Isotopes in Polar Ice: Toward an Absolute Ice Chronometer

    NASA Astrophysics Data System (ADS)

    Aciego, S. M.; Bourdon, B.; Schwander, J.; Stocker, T.

    2007-12-01

    Comparison of ice records between ice sheets, alpine glaciers, and marine records currently rely on a combination of ice layer counting, matching relative time scales, and interpolation. U-series recoil from mineral aerosols (dust) into the ice matrix is one possible technique for determining the absolute age of ice, independent of any other parameters. However, the low concentrations of the U-series parents and daughters have made previous measurements difficult and the results ambiguous. We present here the first results of work we have undertaken for determining U-series recoil ages in ice cores. The primary difficulty of this technique is the extremely low concentrations of dust in polar ice samples, and therefore, of the recoil daughter products in the ice. Previous work on dust provenance indicates 0.01 to 1 mg of dust concentration per kilogram of ice from the ice cores of Greenland and Antarctica. Given these conditions, U and Th dissolved in the water fraction of the aerosol-ice system may overwhelm the total U-series budget. Constraining the possible "initial" U and Th is the first step in determining the feasibility of this dating method for ice cores. We have implemented new geochemical techniques: ultra-clean ice processing, multiple ion counter ICP-MS measurements of U and Th, and quantification of total recoveries of the aerosol and water fractions using both established USGS standards, an internal lab loess standard that best approximates the dust fraction found in ice cores, and [U]-[Th] standards SRM960 and Th105. Dissolution experiments using U and Th spikes with these standards indicate recovery of the dust and dissolved fractions are better than 99%. We present here the first concentration measurements of U from the water fraction (<0.2 microns) of freshly deposited South Pole snow (20pg/kg), as well as a series of measurements from the upper section (~128m) of the Dye 3 ice core in Greenland which thus far range from 410pg/kg to 520fg/kg U

  20. Absolute light and resolution measurements for sensitive CsI(Tl)/photodiode detectors

    NASA Astrophysics Data System (ADS)

    Meier, Michael M.

    2003-01-01

    To conserve volume and power, photodiode/scintillator combinations are strong candidates for gamma-ray detection in space applications. High sensitivity to MeV gamma rays necessitates large-volume scintillators, which are most effectively read out with large-area photodiodes. However, because photodiodes have unity gain, the electronic noise limits resolution, and therefore small-area photodiodes that minimize capacitance are preferred. Thus, optimization of resolution involves maximizing light production and transport in the scintillator and light collection in the photodiode, while minimizing photodiode area. Measurements of performance are reported for 1×1×1cm3/10×10mm2, 80cm3/18×18mm2, and 85cm3/10×10mm2 CsI(Tl)/photodiode combinations. Each large scintillator was a single crystal, machined to a geometry that comprised a 40mm diameter × 50mm height cylindrical section that was extended through a 20°conical section to a square face that matched the respective photodiode sensitive surface. Absolute scales were estimated for the light output by measuring the photodiode responses to 241Am (59.54keV), 57Co (122.06 and 136.47keV), and 133Ba (80.99keV) and assuming a value of 3.67eV/electron-hole pair. The photodiode quantum efficiencies for the CsI(Tl) emission spectrum, corrected for Si reflection back into the scintillator, was taken to be 0.835. We obtained values of 58.2, 46.7, and 34.6 photons/keV for the combined light production and transport into the CsI for the 1cm3, ~80cm3, and ~85cm3 detectors, respectively. The best measured resolutions at 662keVfor the detectors were 5.9%, 7.2%, and 7.4% FWHM, respectively.

  1. Absolute distance measurement with micrometer accuracy using a Michelson interferometer and the iterative synthetic wavelength principle.

    PubMed

    Alzahrani, Khaled; Burton, David; Lilley, Francis; Gdeisat, Munther; Bezombes, Frederic; Qudeisat, Mohammad

    2012-02-27

    We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty of the order of one micrometer, within a timeframe of 40 seconds. The proposed system uses a Michelson interferometer, a tunable laser, a wavelength meter and a computer for analysis. The principle of synthetic wave creation is used in a novel way in that the system employs an initial low precision estimate of the distance, obtained using a triangulation, or time-of-flight, laser system, or similar, and then iterates through a sequence of progressively smaller synthetic wavelengths until it reaches micrometer uncertainties in the determination of the distance. A further novel feature of the system is its use of Fourier transform phase analysis techniques to achieve sub-wavelength accuracy. This method has the major advantages of being relatively simple to realize, offering demonstrated high relative precisions better than 5 × 10(-5). Finally, the fact that this device does not require a continuous line-of-sight to the target as is the case with other configurations offers significant advantages.

  2. ARCADE 2 Measurement of the Absolute Sky Brightness at 3-90 GHz

    NASA Technical Reports Server (NTRS)

    Fixsen, D. J.; Kogut, A.; Levin, S.; Limon, M.; Mirel, P.; Seiffert, M.; Singal, J.; Wollack, E.; Villela, T.; Wuensche, C. A.

    2011-01-01

    The ARCADE 2 instrument has measured the absolute temperature of the sky at frequencies 3, 8, 10, 30, and 90 GHz, uSing an open-aperture cryogenic instrument observing al balloon altitudes with no emissive windows between the beam-forming optics and the sky. An external blackbody calibrator provides an in situ reference. Systematic errors were greatly reduced by using differential radiometers and cooling all critical components to physical temperatures approximating the cosmic microwave background (CMB) temperature. A linear model is used to compare the output of each radiometer to a set of thermometers on the instrument. Small correction. are made for the residual emission from the flight train, balloon, atmosphere, and foreground Galactic emission. The ARCADE 2 data alone show an excess radio rise of 54 +/- 6 mK at 3.3 GHz in addition to a CMB temperature of 2.731 +/- 0.004 K. Combining the ARCADE 2 data with data from the literature shows an excess power-law spectrum of T = 24.1 +/- 2.1 (K)(v/v(sub o)(exp -2.599+/-0.036 from 22 MHz to 10 GHz (v(sub 0) = 310 MHz) in addition to a CMB temperature of 2.725 +/- 0.001 K.

  3. ELENA MCP detector: absolute efficiency measurement for low energy neutral atoms

    NASA Astrophysics Data System (ADS)

    Rispoli, R.; De Angelis, E.; Colasanti, L.; Vertolli, N.; Orsini, S.; Scheer, J.; Mura, A.; Milillo, A.; Wurz, P.; Selci, S.; Di Lellis, A. M.; Leoni, R.; D'Alessandro, M.; Mattioli, F.; Cibella, S.

    2012-04-01

    MicroChannel plates (MCP) detectors are frequently used in space instrumentation for detecting a wide range of radiation and particles. In particular, the capability to detect non-thermal low energy neutral species is crucial for the sensor ELENA (Emitted Low-Energy Neutral Atoms), part of the package SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) on board the BepiColombo mission to Mercury to be launched in 2014. ELENA is a TOF sensor, based on a novel concept ultra-sonic oscillating shutter (Start section)which is operated at frequencies up to 50 kHz; a MCP detector is used as a Stop section. It is aimed to detect neutral atoms in the range 10 eV - 5 keV, within 70° FOV, perpendicular to the S/C orbital plane. ELENA will monitor the emission of neutral atoms from the whole surface of Mercury thanks to the spacecraft motion. The major scientific objectives are the interaction between the environment and the planet, the global particle loss-rate and the remote sensing of the surface properties. In particular, surface release processes are investigated by identifying particles release from the surface, via solar wind-induced ion sputtering (<1eV and >100 eV) as well as Hydrogen back-scattered at hundreds eV. MCP absolute detection efficiency for very low energy neutral atoms (E< 30eV) is a crucial point not yet investigated. At the MEFISTO facility of the Physical Institute of University of Bern (CH), measurements on three different type of MCPs coating have been performed providing the behaviors of MCP detection efficiency in the range 10eV-1keV. Outcomes from such measurements are here discussed.

  4. Measurement of absolute E2 transition strengths in 176W: Signatures for a rapid shape change

    NASA Astrophysics Data System (ADS)

    Fransen, Ch.; Dewald, A.; Friessner, G.; Hackstein, M.; Jolie, J.; Möller, O.; Pissulla, T.; Rother, W.; Zell, K.-O.

    2011-10-01

    The X(5) symmetry describes nuclei at the critical point of the shape phase transition from axially deformed rotor nuclei to spherical vibrators. 150Nd, 152Sm, and 154Gd were the first nuclei where the predicted charateristics of the X(5) symmetry were observed. Later it was shown that also 176,178,180Os can be successfully described with the X(5) symmetry. In the close vicinity of shape phase transitions one expects strongly changing nuclear shapes. In the X(5) region around A = 150 this was observed for nuclei with different neutron numbers, whereas in the X(5) region around A = 180 this is to be expected for different proton numbers. The aim of the work presented here is the confirmation of a rapid shape change for nuclei close to 178Os. Besides the knowledge on the level scheme of the nuclei of interest, especially absolute E2 transition strengths are crucial for the interpretation of nuclear structure. Prolate deformation is expected for 176W. Thus we performed a recoil distance Doppler shift (RDDS) measurement on 176W to measure E2 transition strengths from level lifetimes. The experiment was performed at the Cologne FN TANDEM accelerator with the Cologne coincidence plunger with the reaction 169Dy(16O,4n)176W and a beam energy of 80 MeV. We will present our experimental results and relate them to data on the neighboring nuclei 178Os and 182Pt. The results will be discussed in the framework of nuclear shape transitions in this mass region and compared to calculations with both the Interacting Boson Model (IBM) and the GCM.

  5. Polymer deformation gage measures thickness change in tensile tests

    NASA Technical Reports Server (NTRS)

    Broyles, H. F.; Broyles, H. H.

    1966-01-01

    Lightweight deformation gage attached to a polymer specimen determines the thickness changes undergone by the specimen during the testing of its tensile and elongation properties. Mechanical noise from outside sources is dampened when the assembly is hung on a light rubber band.

  6. Reduced dose measurement of absolute myocardial blood flow using dynamic SPECT imaging in a porcine model

    SciTech Connect

    Timmins, Rachel; Klein, Ran; Petryk, Julia; Marvin, Brian; Kemp, Robert A. de; Ruddy, Terrence D.; Wells, R. Glenn; Wei, Lihui

    2015-09-15

    Purpose: Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements provide important additional information over traditional relative perfusion imaging. Recent advances in camera technology have made this possible with single-photon emission tomography (SPECT). Low dose protocols are desirable to reduce the patient radiation risk; however, increased noise may reduce the accuracy of MBF measurements. The authors studied the effect of reducing dose on the accuracy of dynamic SPECT MBF measurements. Methods: Nineteen 30–40 kg pigs were injected with 370 + 1110 MBq of Tc-99m sestamibi or tetrofosmin or 37 + 111 MBq of Tl-201 at rest + stress. Microspheres were injected simultaneously to measure MBF. The pigs were imaged in list-mode for 11 min starting at the time of injection using a Discovery NM 530c camera (GE Healthcare). Each list file was modified so that 3/4, 1/2, 1/4, 1/8, 1/16, and 1/32 of the original counts were included in the projections. Modified projections were reconstructed with CT-based attenuation correction and an energy window-based scatter correction and analyzed with FlowQuant kinetic modeling software using a 1-compartment model. A modified Renkin-Crone extraction function was used to convert the tracer uptake rate K1 to MBF values. The SPECT results were compared to those from microspheres. Results: Correlation between SPECT and microsphere MBF values for the full injected activity was r ≥ 0.75 for all 3 tracers and did not significantly degrade over all count levels. The mean MBF and MFR and the standard errors in the estimates were not significantly worse than the full-count data at 1/4-counts (Tc99m-tracers) and 1/2-counts (Tl-201). Conclusions: Dynamic SPECT measurement of MBF and MFR in pigs can be performed with 1/4 (Tc99m-tracers) or 1/2 (Tl-201) of the standard injected activity without significantly reducing accuracy and precision.

  7. Comparison of scar thickness measurements using trans-vaginal sonography and MRI in cases of pregnancy with previous caesarean section. Do they correlate with actual scar thickness?

    PubMed

    Singh, N; Tripathi, R; Mala, Y M; Dixit, R; Tyagi, S; Batra, A

    2013-11-01

    The aim of this study was to evaluate scar thickness in cases of pregnancy with previous caesarean section, by trans-vaginal sonography (TVS) and magnetic resonance imaging (MRI), and to correlate precision of radiologically-measured scar thickness with actual measurement of scar thickness. A total of 35 pregnant patients with previous caesarean section planned for elective caesarean section, were evaluated prospectively. Their scar thickness was measured by TVS and MRI on the day of elective repeat caesarean section. These measurements were correlated with each other and with scar thickness measured during elective repeat caesarean section by using a caliper. The correlation coefficients between scar thickness measured by TVS and MRI with peroperative evaluation with a caliper, were +0.72 and +0.59, respectively. The study concluded that as MRI is a costlier modality and TVS has better correlation coefficient with actual scar thickness, TVS can be considered to be the better modality for antenatal scar thickness measurement.

  8. Imperfection and Thickness Measurement of Panels Using a Coordinate Measurement Machine

    NASA Technical Reports Server (NTRS)

    Thornburgh, Robert P.

    2006-01-01

    This paper summarizes the methodology used to measure imperfection and thickness variation for flat and curved panels using a Coordinate Measurement Machine (CMM) and the software program MeasPanel. The objective is to provide a reference document so that someone with a basic understanding of CMM operation can measure a panel with minimal training. Detailed information about both the measurement system setup and computer software is provided. Information is also provided about the format of the raw data, as well as how it is post-processed for use in finite-element analysis.

  9. Thickness measurement of tablet coating using continuous-wave terahertz reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Devi, Nirmala; Dash, Jyotirmayee; Ray, Shaumik; Pesala, Bala

    2016-02-01

    THz rays have higher penetration depth compared to infrared rays and hence can be effectively used to measure tablet coating thickness. In addition, THz wavelength (1 mm - 0.1 mm) provides an optimal depth resolution for the thickness measurement. This method can be non-invasive and hence ideal for inline quality monitoring. Tablet coating thickness is one of the major parameters of interest in Process Analytical Technology (PAT). In this paper, a reflection mode Continuous Wave (CW) Terahertz (THz) system has been employed to measure the tablet coating thickness. A frequency scan of the sample has been carried out from 0.1 THz to 1.1 THz and the reflection coefficient of the sample is inverse fourier transformed to obtain the tablet thickness. The calculated thickness has also been validated using the optical microscope. Results show that the thickness can be measured with considerable accuracy.

  10. The orbit of Phi Cygni measured with long-baseline optical interferometry - Component masses and absolute magnitudes

    NASA Technical Reports Server (NTRS)

    Armstrong, J. T.; Hummel, C. A.; Quirrenbach, A.; Buscher, D. F.; Mozurkewich, D.; Vivekanand, M.; Simon, R. S.; Denison, C. S.; Johnston, K. J.; Pan, X.-P.

    1992-01-01

    The orbit of the double-lined spectroscopic binary Phi Cygni, the distance to the system, and the masses and absolute magnitudes of its components are presented via measurements with the Mar III Optical Interferometer. On the basis of a reexamination of the spectroscopic data of Rach & Herbig (1961), the values and uncertainties are adopted for the period and the projected semimajor axes from the present fit to the spectroscopic data and the values of the remaining elements from the present fit to the Mark III data. The elements of the true orbit are derived, and the masses and absolute magnitudes of the components, and the distance to the system are calculated.

  11. Ultrasonographic Measurement of the Femoral Cartilage Thickness in Hemiparetic Patients after Stroke

    ERIC Educational Resources Information Center

    Tunc, Hakan; Oken, Oznur; Kara, Murat; Tiftik, Tulay; Dogu, Beril; Unlu, Zeliha; Ozcakar, Levent

    2012-01-01

    The aim of the study was to evaluate the femoral cartilage thicknesses of hemiparetic patients after stroke using musculoskeletal ultrasonography and to determine whether there is any correlation between cartilage thicknesses and the clinical characteristics of the patients. Femoral cartilage thicknesses of both knees were measured in 87 (33…

  12. Some triple-filament lead isotope ratio measurements and an absolute growth curve for single-stage leads

    USGS Publications Warehouse

    Stacey, J.S.; Delevaux, M.E.; Ulrych, T.J.

    1969-01-01

    Triple-filament analyses of three standard lead samples are used to calibrate a mass spectrometer in an absolute sense. The bias we measure is 0.0155 percent per mass unit, and the precision (for 95% confidence limits) is ??0.13% or less for all ratios relative to 204Pb. Although its precision is not quite so good as that of the lead-tetramethyl method in the analysis of large samples, the triple-filament method is less complex and is an attractive alternative for smaller sample sizes down to 500 ??g. Triple-filament data are presented for six possibly single-stage lead ores and one feldspar. These new data for ores are combined with corrected tetramethyl data for stratiform lead deposits to compute absolute parameters for a universal single-stage lead isotope growth curve. Absolute isotopic ratios for primeval lead have been determined by Oversby and because all the previous data for both meteorites and lead ores were similarly fractionated, the absolute value of 238U 204Pb = 9.09 ?? 0.06 for stratiform leads is little different from the value 8.99 ?? 0.05 originally computed by Ostic, Russell and Stanton. Absolute values for lead isotope ratios for all interlaboratory standard samples presently available from the literature are tabulated. ?? 1969.

  13. Optical measurement of adipose tissue thickness and comparison with ultrasound, magnetic resonance imging, and callipers

    NASA Astrophysics Data System (ADS)

    Geraskin, Dmitri; Boeth, Heide; Kohl-Bareis, Matthias

    2009-07-01

    Near-infrared spectroscopy is used to quantify the subcutaneous adipose tissue thickness (ATT) over five muscle groups (vastus medialis, vastus lateralis, gastrocnemius, ventral forearm and biceps brachii muscle) of healthy volunteers (n=20). The optical lipid signal (OLS) was obtained from the second derivative of broad band attenuation spectra and the lipid absorption peak (λ=930 nm). Ultrasound and MR imaging as well as mechanical calliper readings were taken as reference methods. The data show that the OLS is a good predictor for ATT (<16 mm) with absolute and relative errors of <0.8 mm and <24%, respectively. The optical method compares favourably with calliper reading. The finding of a non-linear relationship of optical signal vs. ultrasound is explained by a theoretical two-layer model based on the diffusion approximation for the transport of photons. The crosstalk between the OLS and tissue hemoglobin concentration changes during an incremental cycling exercise was found to be small, indicating the robustness of OLS. Furthermore, the effect of ATT on spatially-resolved spectroscopy measurements is shown to decrease the calculated muscle hemoglobin concentration and to increase oxygen saturation.

  14. Application of the Ultrasonic Oil Film Thickness Measurement System in Bearing Chambers

    NASA Astrophysics Data System (ADS)

    Zhong, Chong; Hu, Jian-ping; Liu, Zhen-xia; Lu, Ya-guo; Hao, Yu-ya

    2014-06-01

    The oil film thickness in aero-engine bearing chamber influences the heat transfer capacity of the bearing chamber wall, so measuring oil film thickness accuspeedly is essential to the design and thermal analysis of lubricating oil system. In this paper, software and hardware of an ultrasonic measurement system based on pulse echo technique, which measures the oil film thickness in bearing chamber, are established. The hardware system mainly consists of signal acquisition card, probe, delay block and the corresponding cables. Functions as measurement parameter setup, real-time display of measured waveforms, post-processing and so on are included in the measurement software. Finally, the oil film thickness of the wall is measured with the measurement system developed. Signal quality of the dynamic measurement is analyzed. Comparison and analysis of different oil film thickness under different rotation rates are conducted.

  15. Field Measurement of Sand Dune Bidirectional Reflectance Characteristics for Absolute Radiometric Calibration of Optical Remote Sensing Data.

    NASA Astrophysics Data System (ADS)

    Coburn, C. A.; Logie, G.; Beaver, J.; Helder, D.

    2015-12-01

    The use of Pseudo Invariant Calibration Sites (PICS) for establishing the radiometric trending of optical remote sensing systems has a long history of successful implementation. Past studies have shown that the PICS method is useful for evaluating the trend of sensors over time or cross-calibration of sensors but was not considered until recently for deriving absolute calibration. Current interest in using this approach to establish absolute radiometric calibration stems from recent research that indicates that with empirically derived models of the surface properties and careful atmospheric characterisation Top of Atmosphere (TOA) reflectance values can be predicted and used for absolute sensor radiometric calibration. Critical to the continued development of this approach is the accurate characterization of the Bidirectional Reflectance Distribution Function (BRDF) of PICS sites. This paper presents the field data collected by a high-performance portable goniometer system in order to develop a BRDF model for the Algodones Dunes in California. These BRDF data are part of a larger study that is seeking to evaluate and quantify all aspects of this dune system (from regional effects to the micro scale optical properties of the sand) in order to provide an absolute radiometric calibration PICS. This paper presents the results of a dense temporal measurement sequence (several measurements per hour with high angular resolution), to yield detailed information on the nature of the surface reflectance properties. The BRDF data were collected covering typical view geometry of space borne sensors and will be used to close the loop on the calibration to create an absolute calibration target for optical satellite absolute radiometric calibration.

  16. Multi-Segment Radius Measurement Using an Absolute Distance Meter Through a Null Assembly

    NASA Technical Reports Server (NTRS)

    Merle, Cormic; Wick, Eric; Hayden, Joseph

    2011-01-01

    This system was one of the test methods considered for measuring the radius of curvature of one or more of the 18 segmented mirrors that form the 6.5 m diameter primary mirror (PM) of the James Webb Space Telescope (JWST). The assembled telescope will be tested at cryogenic temperatures in a 17-m diameter by 27-m high vacuum chamber at the Johnson Space Center. This system uses a Leica Absolute Distance Meter (ADM), at a wavelength of 780 nm, combined with beam-steering and beam-shaping optics to make a differential distance measurement between a ring mirror on the reflective null assembly and individual PM segments. The ADM is located inside the same Pressure-Tight Enclosure (PTE) that houses the test interferometer. The PTE maintains the ADM and interferometer at ambient temperature and pressure so that they are not directly exposed to the telescope s harsh cryogenic and vacuum environment. This system takes advantage of the existing achromatic objective and reflective null assembly used by the test interferometer to direct four ADM beamlets to four PM segments through an optical path that is coincident with the interferometer beam. A mask, positioned on a linear slide, contains an array of 1.25 mm diameter circular subapertures that map to each of the 18 PM segments as well as six positions around the ring mirror. A down-collimated 4 mm ADM beam simultaneously covers 4 adjacent PM segment beamlets and one ring mirror beamlet. The radius, or spacing, of all 18 segments can be measured with the addition of two orthogonally-oriented scanning pentaprisms used to steer the ADM beam to any one of six different sub-aperture configurations at the plane of the ring mirror. The interferometer beam, at a wavelength of 687 nm, and the ADM beamlets, at a wavelength of 780 nm, pass through the objective and null so that the rays are normally incident on the parabolic PM surface. After reflecting off the PM, both the ADM and interferometer beams return to their respective

  17. Design of a quasi-zero-stiffness based sensor system for the measurement of absolute vibration displacement of moving platforms

    NASA Astrophysics Data System (ADS)

    Jing, Xingjian; Wang, Yu; Li, Quankun; Sun, Xiuting

    2016-09-01

    This study presents the analysis and design of a novel sensor system for measuring the absolute vibration displacement of moving platforms based on the concept of quasi-zero-stiffness (QZS). The sensor system is constructed using positive- and negative-stiffness springs, which make it possible to achieve an equivalent QZS and consequently to create a broadband vibration-free point for absolute vibration displacement measurement in moving platforms. Theoretical analysis is conducted for the analysis and design of the influence of structure parameters on system measurement performance. A prototype is designed which can avoid the drawback of instability in existing QZS systems with negative stiffness, and corresponding data-processing software is developed to fulfill time domain measurements. Both the simulation and experimental results verify the effectiveness of this novel sensor system.

  18. A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Rodahl, Michael; Kasemo, Bengt

    1996-09-01

    An experimental setup is described that can simultaneously measure the absolute dissipation factor and the resonant frequency of a short-circuited quartz crystal microbalance. The crystal is driven at approximately its resonant frequency by a signal generator which is intermittently disconnected by a relay, causing the crystal oscillation amplitude to decay exponentially. The decay is measured using a ferrite toroid transformer. One of the crystal leads is fed through the center of the ferrite toroid and thereby acts as the primary winding of the transformer. The secondary winding of the transformer is connected to a digitizing oscilloscope which records the decay of the crystal oscillation. From the recorded decay curve, the absolute dissipation factor (calculated from the decay time constant) and the series resonant frequency of the freely oscillating crystal are obtained. Alternatively, the dissipation factor and resonant frequency can be measured for the crystal oscillating under open-circuit conditions, i.e., in the parallel mode. The measurements are automated.

  19. The effect of food consumption on the thickness of abdominal muscles, employing ultrasound measurements.

    PubMed

    Kordi, Ramin; Rostami, Mohsen; Noormohammadpour, Pardis; Mansournia, Mohammad Ali

    2011-08-01

    Recently, the roles of transabdominal muscles particularly TrA (transverse abdominis) muscle in spinal stability leading to treatment of low back pain have been suggested. Both in clinical setting and follow up studies, abdominal muscle thickness measurements need to be repeated at a later point in time to demonstrate efficacy of a therapeutic intervention. Different issues have been suggested as source of error in the repeated measurements of abdominal muscle thickness in different days such as patient position and stability of probe location. The level of stomach fullness has not been investigated as a source of error in ultrasonic measurements of transabdominal muscles thickness. This study was performed to evaluate the effect of food consumption on thickness of lateral abdominal muscles. Lateral abdominal muscles thicknesses of 63 healthy volunteer men were measured before and after food consumption. All the measurements were performed in two transducer positions and both sides. Waist circumference and body weight of participants were also measured before and post-food consumption. The thickness measures of all three muscles layers of lateral abdominal muscles (external oblique, internal oblique and transversus abdominis) in both sides and measured positions were significantly reduced after food consumption. We found no correlation between the increase of waist circumference and reduction of muscle layer thicknesses after food consumption. In case of comparison between the values of transabdominal muscle thicknesses over the time, the effect of food consumption on muscle thickness might be assumed as a potential source of error.

  20. High-accuracy interferometer with a prism pair for measurement of the absolute refractive index of glass

    SciTech Connect

    Hori, Yasuaki; Hirai, Akiko; Minoshima, Kaoru; Matsumoto, Hirokazu

    2009-04-10

    We propose a variable-path interferometric technique for the measurement of the absolute refractive index of optical glasses. We use two interferometers to decide the ratio between changes in the optical path in a prism-shaped sample glass and in air resulting from displacement of the sample. The method allows precise measurements to be made without prior knowledge of the properties of the sample. The combined standard uncertainty of the proposed method is 1.6x10{sup -6}.

  1. Measurements of refractive index and physical thickness using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Song, Guiju; Wang, Xiangzhao; Ren, Hongwu; Zhang, Weizai; Zhang, Lianying; Fang, Zujie

    2000-05-01

    The measurements of refractive index and thickness of various transparent plates and films are very important for quality control. Additionally, the knowledge of refractive index, and thickness is significant in biomedicine for the treatment of many kinds of tumors. In this paper, we propose a new method for noninvasive and simultaneous measurement of refractive indices and physical thickness of specimens, which consist of surrounding and interior components with different refractive indices. In our experiment, we measure the refractive index and the physical thickness of a multimode fiber and a lotus root with a hollow hole, respectively. The experimental results verify the feasibility of this method.

  2. Measuring the absolute deuterium-tritium neutron yield using the magnetic recoil spectrometer at OMEGA and the NIF.

    PubMed

    Casey, D T; Frenje, J A; Gatu Johnson, M; Séguin, F H; Li, C K; Petrasso, R D; Glebov, V Yu; Katz, J; Knauer, J P; Meyerhofer, D D; Sangster, T C; Bionta, R M; Bleuel, D L; Döppner, T; Glenzer, S; Hartouni, E; Hatchett, S P; Le Pape, S; Ma, T; MacKinnon, A; McKernan, M A; Moran, M; Moses, E; Park, H-S; Ralph, J; Remington, B A; Smalyuk, V; Yeamans, C B; Kline, J; Kyrala, G; Chandler, G A; Leeper, R J; Ruiz, C L; Cooper, G W; Nelson, A J; Fletcher, K; Kilkenny, J; Farrell, M; Jasion, D; Paguio, R

    2012-10-01

    A magnetic recoil spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

  3. A Technique for Measuring the Thickness of a Thin Contaminant Layer

    DTIC Science & Technology

    A method of determining the thickness of a known contaminant on a 77K metallic reflecting surface is considered. A single reflectance measurement is used to determine the thickness after the optical constants of the contaminant and the reflecting surface have been determined. An existing research chamber is modified for experimental evaluation of this approach to a thickness measurement, and an experimental program is outlined. (Author)

  4. Enhanced cortical thickness measurements for rodent brains via Lagrangian-based RK4 streamline computation

    NASA Astrophysics Data System (ADS)

    Lee, Joohwi; Kim, Sun Hyung; Oguz, Ipek; Styner, Martin

    2016-03-01

    The cortical thickness of the mammalian brain is an important morphological characteristic that can be used to investigate and observe the brain's developmental changes that might be caused by biologically toxic substances such as ethanol or cocaine. Although various cortical thickness analysis methods have been proposed that are applicable for human brain and have developed into well-validated open-source software packages, cortical thickness analysis methods for rodent brains have not yet become as robust and accurate as those designed for human brains. Based on a previously proposed cortical thickness measurement pipeline for rodent brain analysis,1 we present an enhanced cortical thickness pipeline in terms of accuracy and anatomical consistency. First, we propose a Lagrangian-based computational approach in the thickness measurement step in order to minimize local truncation error using the fourth-order Runge-Kutta method. Second, by constructing a line object for each streamline of the thickness measurement, we can visualize the way the thickness is measured and achieve sub-voxel accuracy by performing geometric post-processing. Last, with emphasis on the importance of an anatomically consistent partial differential equation (PDE) boundary map, we propose an automatic PDE boundary map generation algorithm that is specific to rodent brain anatomy, which does not require manual labeling. The results show that the proposed cortical thickness pipeline can produce statistically significant regions that are not observed in the previous cortical thickness analysis pipeline.

  5. Enhanced Cortical Thickness Measurements for Rodent Brains via Lagrangian-based RK4 Streamline Computation

    PubMed Central

    Lee, Joohwi; Kim, Sun Hyung; Oguz, Ipek; Styner, Martin

    2016-01-01

    The cortical thickness of the mammalian brain is an important morphological characteristic that can be used to investigate and observe the brain’s developmental changes that might be caused by biologically toxic substances such as ethanol or cocaine. Although various cortical thickness analysis methods have been proposed that are applicable for human brain and have developed into well-validated open-source software packages, cortical thickness analysis methods for rodent brains have not yet become as robust and accurate as those designed for human brains. Based on a previously proposed cortical thickness measurement pipeline for rodent brain analysis,1 we present an enhanced cortical thickness pipeline in terms of accuracy and anatomical consistency. First, we propose a Lagrangian-based computational approach in the thickness measurement step in order to minimize local truncation error using the fourth-order Runge-Kutta method. Second, by constructing a line object for each streamline of the thickness measurement, we can visualize the way the thickness is measured and achieve sub-voxel accuracy by performing geometric post-processing. Last, with emphasis on the importance of an anatomically consistent partial differential equation (PDE) boundary map, we propose an automatic PDE boundary map generation algorithm that is specific to rodent brain anatomy, which does not require manual labeling. The results show that the proposed cortical thickness pipeline can produce statistically significant regions that are not observed in the the previous cortical thickness analysis pipeline. PMID:27065047

  6. Assessment of Nuclear Fuels using Radiographic Thickness Measurement Method

    SciTech Connect

    Muhammad Abir; Fahima Islam; Hyoung Koo Lee; Daniel Wachs

    2014-11-01

    The Convert branch of the National Nuclear Security Administration (NNSA) Global Threat Reduction Initiative (GTRI) focuses on the development of high uranium density fuels for research and test reactors for nonproliferation. This fuel is aimed to convert low density high enriched uranium (HEU) based fuel to high density low enriched uranium (LEU) based fuel for high performance research reactors (HPRR). There are five U.S. reactors that fall under the HPRR category, including: the Massachusetts Institute of Technology Reactor (MITR), the National Bureau of Standards Reactor (NBSR), the Missouri University Research Reactor (UMRR), the Advanced Test Reactor (ATR), and the High Flux Isotope Reactor (HFIR). U-Mo alloy fuel phase in the form of either monolithic or dispersion foil type fuels, such as ATR Full-size In center flux trap Position (AFIP) and Reduced Enrichment for Research and Test Reactor (RERTR), are being designed for this purpose. The fabrication process1 of RERTR is susceptible to introducing a variety of fuel defects. A dependable quality control method is required during fabrication of RERTR miniplates to maintain the allowable design tolerances, therefore evaluating and analytically verifying the fabricated miniplates for maintaining quality standards as well as safety. The purpose of this work is to analyze the thickness of the fabricated RERTR-12 miniplates using non-destructive technique to meet the fuel plate specification for RERTR fuel to be used in the ATR.

  7. Elastohydrodynamic film thickness formula based on X-ray measurements with a synthetic paraffinic oil

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

    1973-01-01

    An empirical elastohydrodynamic film thickness formula for heavily loaded contacts based upon X-ray film thickness measurements made with a synthetic paraffinic oil is presented. The deduced relation was found to adequately reflect the high load dependence exhibited by the measured minimum film thickness data at high Hertizian contact stresses, that is, above 1.04 x 10 to the ninth N/sq m (150,000 psi). Comparisons were made with the numerical results from a theoretical isothermal film thickness formula. The effects of changes in contact geometry, material, and lubricant properties on the form of the empirical model are also discussed.

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

    SciTech Connect

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

    2010-06-30

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

  9. Aerosol Optical Thickness Derived From Atmospheric Transmittance Using Spectroradiometer Measurements

    NASA Astrophysics Data System (ADS)

    Hwee San, Hslim; Matjafri, M. Z.; Abdullah, Abdul K.; Chow Jeng, C. J.

    section The objective of this study was to test the feasibility of hand held spectroradiometer measurements for the retrieval AOT values Twenty-six stations were chosen randomly around Penang Island and the atmospheric transmittance measurements were collected using a handheld spectroradiometer The corresponding PM10 concentrations were measured using a portable DustTrak Aerosol Monitor 8520 simultaneously with the measurements of the transmittance data The AOT values were calculated using the Beer-Lambert-Bouguer law Linear relationship was found between AOT and PM10 values in this study Finally a PM10 map was created using Kriging interpolation technique The result of the study showed the potential of a spectroradiometer data for the retrieval of AOT and PM10 to provide the air pollution information

  10. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    PubMed

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted.

  11. Research on the measurement of thin film thickness based on phaseshift interferometry

    NASA Astrophysics Data System (ADS)

    Shi, Yi-lei; Su, Jun-hong; Yang, Li-hong; Xu, Jun-qi

    2009-05-01

    Only by solving the problem of accurate measurement of thin film thickness, will it be possible to solve the problem of thin film preparation. A novel measurement method of thin film thickness based on phase-shift interferometry is presented in the paper. Taking advantage of Twyman-Green interferometer, the multi-frame interferogram measured the thin film can be obtained by receiving the interference fringes of thin film by means of CCD and using digital acquisition card to collect interferogram and with the help of computer control PZT driver and modulation piezoelectric regulator to promote reference mirror uniformly-spaced movement. After the gained interferogram were disposed of phase unwrapped, 3D wavefront containing the information of thin film thickness can be obtained. According to the characteristics between the thin film thickness and the unwrapping phase, taking advantage of the overlapping 4-frame average algorithm, corresponding relationships between the quantification phase information and thin film thickness of each point has been established to realize the thin film thickness accurate measurement. The results show that this method has the advantage of non-contact, the high accuracy, not only has testified the feasibility of film thickness measurement with phase-shift interferometry, but also has further ensured research and optimization of the thin film preparation technics. The PV and RMS value of the measured thin film thickness are 0.162μm and 0.043μm respectively.

  12. Combining sub-Nyquist sampling and chirp decomposition for a high-precision and speed absolute distance measurement method.

    PubMed

    Liu, Guodong; Lu, Cheng; Liu, Bingguo; Chen, Fengdong; Gan, Yu

    2016-12-10

    A high-precision and speed absolute distance measurement based on swept-wavelength interferometry is reported. A powerful method combining sub-Nyquist sampling and chirp decomposition for dispersion mismatch compensation is proposed. A standard deviation of 0.72 μm is obtained for the measurement of a target located at 3.9 m, which is better than the traditional method. The measurement can be completed in 1.9 s when the frequency range is 4.26 THz, which is much better than chirp decomposition without sub-Nyquist sampling.

  13. Double Film Thickness Measurements In The Semiconductor Industry

    NASA Astrophysics Data System (ADS)

    Spanier, Richard F.

    1982-10-01

    Ellipsometry as a technique for the measurement of the optical constants (n,k,d) of two layer films on substrates is presented in a tutorial fashion. The ideal two layer film model is described and departures from ideality that are likely to be encounterd in a real sample are discussed. The ellipsometric measurement of the change in polarization state upon reflection as well as the determination of the optical reflection angles DELTA and PSI are reviewed. Extraction of the optical constants from the DELTA, PSI measurement is discussed at length. Examples are drawn from double film systems of interest to the semi-conductor industry but the principles and procedures of analysis illustrated by these examples have general application.

  14. Numerical and experimental demonstration of shear stress measurement at thick steel plates using acoustoelasticity

    NASA Astrophysics Data System (ADS)

    Abbasi, Zeynab; Ozevin, Didem

    2015-04-01

    The purpose of this article is to numerically quantify the stress state of complex loaded thick steel plates using the fundamental theory of acoustoelasticity, which is the relationship with stress and ultrasonic velocity in the nonlinear regime. The normal and shear stresses of a thick plate can be measured using a phased array placement of ultrasonic sensors and Rayleigh ultrasonic waves. Three measurement angles (i.e., 0 45 and 90 degrees) are selected since three measurements are needed to solve the stress tensor in an isotropic plate. The ultrasonic data is influenced significantly by the frequency of the Rayleigh waves as well as the thickness of the plate being examined; consequently the overall experimental process is influenced by the measurement parameters. In this study, a numerical demonstration is implemented to extract the nonlinearity coefficients using a 3D structural geometry and Murnaghan material model capable of examining the effects of various plate thicknesses and ultrasonic frequencies on the shear stress measurement. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The correlation between the depth of penetration and shear stress is then obtained. The numerical results are compared with 1 MHz ultrasonic frequency and a 3/8 inch thick steel plate loaded uniaxially while the measurement direction is angled to have the presence of shear stress in the measurement direction.

  15. Silicon Absolute X-Ray Detectors

    SciTech Connect

    Seely, John F.; Korde, Raj; Sprunck, Jacob; Medjoubi, Kadda; Hustache, Stephanie

    2010-06-23

    The responsivity of silicon photodiodes having no loss in the entrance window, measured using synchrotron radiation in the 1.75 to 60 keV range, was compared to the responsivity calculated using the silicon thickness measured using near-infrared light. The measured and calculated responsivities agree with an average difference of 1.3%. This enables their use as absolute x-ray detectors.

  16. Dimensions of the human sclera: Thickness measurement and regional changes with axial length.

    PubMed

    Norman, Richard E; Flanagan, John G; Rausch, Sophie M K; Sigal, Ian A; Tertinegg, Inka; Eilaghi, Armin; Portnoy, Sharon; Sled, John G; Ethier, C Ross

    2010-02-01

    Scleral thickness, especially near the region of the optic nerve head (ONH), is a potential factor of interest in the development of glaucomatous optic neuropathy. Our goal was to characterize the scleral thickness distribution and other geometric features of human eyes. Eleven enucleated human globes (7 normal and 4 ostensibly glaucomatous) were imaged using high-field microMRI, providing 80 microm isotropic resolution over the whole eye. The MRI scans were segmented to produce 3-D corneoscleral shells. Each shell was divided into 15 slices along the anterior-posterior axis of the eye, and each slice was further subdivided into the anatomical quadrants. Average thickness was measured in each region, producing 60 thickness measurements per eye. Hierarchical clustering was used to identify trends in the thickness distribution, and scleral geometric features were correlated with globe axial length. Thickness over the whole sclera was 670 +/- 80 microm (mean +/- SD; range: 564 microm-832 microm) over the 11 eyes. Maximum thickness occurred at the posterior pole of the eye, with mean thickness of 996 +/- 181 microm. Thickness decreased to a minimum at the equator, where a mean thickness of 491 +/- 91 microm was measured. Eyes with a reported history of glaucoma were found to have longer axial length, smaller ONH canal dimensions and thinner posterior sclera. Several geometrical parameters of the eye, including posterior scleral thickness, axial length, and ONH canal diameter, appear linked. Significant intra-individual and inter-individual variation in scleral thickness was evident. This may be indicative of inter-individual differences in ocular biomechanics.

  17. Radar Thickness Measurements over the Southern Part of the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Chuah, Teong Sek; Gogineni, Siva Prasad; Allen, Christopher; Wohletz, Brad; Wong, Y. C.; Ng, P. Y.; Ajayi, E.

    1996-01-01

    We performed ice thickness measurements over the southern part of the Greenland ice sheet during June and July 1993. We used an airborne coherent radar depth sounder for these measurements. The radar was operated from a NASA P-3 aircraft equipped with GPS receivers. Radar data were collected in conjunction with laser altimeter and microwave altimeter measurements of ice surface elevation. This report provides radio echograms and thickness profiles from data collected during 1993.

  18. Synchrotron measurements of the absolute x-ray quantum efficiency of CsI-coated microchannel plates

    NASA Astrophysics Data System (ADS)

    Rideout, Rob M.; Pearson, James F.; Fraser, George W.; Lees, John E.; Brunton, Adam N.; Bannister, N. P.; Kenter, Almus T.; Kraft, Ralph P.

    1998-11-01

    Two identical CsI-coated, low noise microchannel plate (MCP) detectors were taken to the Daresbury Synchrotron Radiation Source (SRS) to measure their quantum efficiencies over two different energy ranges - 450 eV to 1200 eV and 4.5 eV to 9.5 eV. The SRS was run in low ring current with the beam flux monitored using single wire gas proportional counters. We present accurate measurements of edge-related absolute quantum efficiency features due to the CsI photocathodes. This data will be incorporated into the calibration program of the Advanced X-ray Astrophysical Facility High Resolution Camera.

  19. Absolute frequency measurement of the {{}^{1}}{{\\text{S}}_{0}} – {{}^{3}}{{\\text{P}}_{0}} transition of 171Yb

    NASA Astrophysics Data System (ADS)

    Pizzocaro, Marco; Thoumany, Pierre; Rauf, Benjamin; Bregolin, Filippo; Milani, Gianmaria; Clivati, Cecilia; Costanzo, Giovanni A.; Levi, Filippo; Calonico, Davide

    2017-02-01

    We report the absolute frequency measurement of the unperturbed transition {{}1}{{\\text{S}}0} – {{}3}{{\\text{P}}0} at 578 nm in 171Yb realized in an optical lattice frequency standard relative to a cryogenic caesium fountain. The measurement result is 518 295 836 590 863.59(31) Hz with a relative standard uncertainty of 5.9× {{10}-16} . This value is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the International System of Units.

  20. Tomographic imaging of absolute optical absorption coefficient in turbid media using combined photoacoustic and diffusing light measurements.

    PubMed

    Yin, Lu; Wang, Qiang; Zhang, Qizhi; Jiang, Huabei

    2007-09-01

    We present a new method that can provide high resolution images of absolute optical absorption coefficient in heterogeneous turbid media. In this method, acoustic measurements in conventional photoacoustic tomography are combined with diffusing light measurements to separate the product of absorption coefficient and optical fluence or photon density. We validate this method using a series of tissuelike phantom experiments. The experimental results show that targets as small as 0.5 mm in diameter with optical absorption contrasts as low as 1.5 relative to a 50 mm diameter scattering background medium can be clearly detected.

  1. Macular thickness and macular volume measurements using spectral domain optical coherence tomography in normal Nepalese eyes

    PubMed Central

    Pokharel, Amrit; Shrestha, Gauri Shankar; Shrestha, Jyoti Baba

    2016-01-01

    Purpose To record the normative values for macular thickness and macular volume in normal Nepalese eyes. Methods In all, 126 eyes of 63 emmetropic subjects (mean age: 21.17±6.76 years; range: 10–37 years) were assessed for macular thickness and macular volume, using spectral domain-optical coherence tomography over 6×6 mm2 in the posterior pole. A fast macular thickness protocol was employed. Statistics such as the mean, median, standard deviation, percentiles, and range were used, while a P-value was set at 0.05 to test significance. Results Average macular thickness and total macular volume were larger in males compared to females. With each year of increasing age, these variables decreased by 0.556 μm and 0.0156 mm3 for average macular thickness and total macular volume, respectively. The macular thickness was greatest in the inner superior section and lowest at the center of the fovea. The volume was greatest in the outer nasal section and thinnest in the fovea. The central subfield thickness (r=−0.243, P=0.055) and foveal volume (r=0.216, P=0.09) did not correlate with age. Conclusion Males and females differ significantly with regard to macular thickness and macular volume measurements. Reports by other studies that the increase in axial length reduced thickness and volume, were negated by this study which found a positive correlation among axial length, thickness, and volume. PMID:27041990

  2. Thickness measurement of multi-layer conductive coatings using multifrequency eddy current techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Dejun; Yu, Yating; Lai, Chao; Tian, Guiyun

    2016-07-01

    To ensure the key structural performance in high-temperature and high-stress environments, thermal barrier coatings (TBCs) are often adopted in engineering. The thickness of these multi-layer conductive coatings is an important quality indicator. In order to measure the thickness of multi-layer conductive coatings, a new measurement approach is presented using eddy current testing techniques, and then, an inversion algorithm is proposed and proved efficient and applicable, of which the maximum experimental relative error is within 10%. Therefore, the new approach can be effectively applied to thickness measurement of multi-layer conductive coatings such as TBCs.

  3. An X-ray monitor for measurement of a titanium tritide target thickness

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Steinberg, R.

    1972-01-01

    An X-ray device capable of measuring titanium tritide film thickness from 0.1 to 30 micrometers has been built and tested. The monitor was designed for use in a rotating target system which used thick targets and incorporated a sputtering electrode to remove depleted layers from the target surface. The thickness measurement can be done in the presence of an intense background of bremsstrahlung and characteristic titanium X-radiation. A measurement can be accomplished in situ in two hours with reasonable accuracy.

  4. Thin-film thickness profile measurement by three-wavelength interference color analysis.

    PubMed

    Kitagawa, Katsuichi

    2013-04-01

    Conventional transparent film thickness measurement methods such as spectroscopy are essentially capable of measuring only a single point at a time, and their spatial resolution is limited. We propose a film thickness measurement method that is an extension of the global model-fitting algorithm developed for three-wavelength interferometric surface profiling. It estimates the film thickness distribution from an interference color image captured by a color camera with three-wavelength illumination. The proposed method is validated through computer simulations and experiments.

  5. Comparison between muscle activation measured by electromyography and muscle thickness measured using ultrasonography for effective muscle assessment.

    PubMed

    Kim, Chang-Yong; Choi, Jong-Duk; Kim, Suhn-Yeop; Oh, Duck-Won; Kim, Jin-Kyung; Park, Ji-Whan

    2014-10-01

    In this study, we aimed to compare the intrarater reliability and validity of muscle thickness measured using ultrasonography (US) and muscle activity via electromyography (EMG) during manual muscle testing (MMT) of the external oblique (EO) and lumbar multifidus (MF) muscles. The study subjects were 30 healthy individuals who underwent MMT at different grades. EMG was used to measure the muscle activity in terms of ratio to maximum voluntary contraction (MVC) and root mean square (RMS) metrics. US was used to measure the raw muscle thickness, the ratio of muscle thickness at MVC, and the ratio of muscle thickness at rest. One examiner performed measurements on each subject in 3 trials. The intrarater reliabilities of the % MVC RMS and raw RMS metrics for EMG and the % MVC thickness metrics for US were excellent (ICC=0.81-0.98). There was a significant difference between all the grades measured using the % MVC thickness metric (p<0.01). Further, this % MVC thickness metric of US showed a significantly higher correlation with the EMG measurement methods than with the others (r=0.51-0.61). Our findings suggest that the % MVC thickness determined by US was the most sensitive of all methods for assessing the MMT grade.

  6. Non-contacting Measurement of Oil Film Thickness Between Loaded Metallic Gear Teeth

    NASA Astrophysics Data System (ADS)

    Cox, Daniel B.; Ceccio, Steven L.; Dowling, David R.

    2013-11-01

    The mechanical power transmission efficiency of gears is depends on the lubrication condition between gear teeth. While the lubrication levels can be generally predicted, an effective in-situ non-contacting measurement of oil film thicknesses between loaded metallic gear teeth has proved elusive. This study explores a novel oil film thickness measurement technique based on optical fluence, the light energy transmitted between loaded gear teeth. A gear testing apparatus that allowed independent control of gear rotation rate, load torque, and oil flow was designed and built. Film thickness measurements made with 5-inch-pitch-diameter 60-tooth spur gears ranged from 0.3 to 10.2 mil. These results are compared with film thickness measurements made in an earlier investigation (MacConochie and Cameron, 1960), as well as with predictions from two film thickness models: a simple two-dimensional squeezed oil film and the industry-accepted model as described by the American Gear Manufacturers Association (AGMA 925, 2003). In each case, the measured film thicknesses were larger than the predicted thicknesses, though these discrepancies might be attributed to the specifics the experiments and to challenges associated with calibrating the fluence measurements. [Sponsored by General Electric].

  7. High stability multiplexed fiber interferometer and its application on absolute displacement measurement and on-line surface metrology.

    PubMed

    Lin, Dejiao; Jiang, Xiangqian; Xie, Fang; Zhang, Wei; Zhang, Lin; Bennion, Ian

    2004-11-15

    We propose a self-reference multiplexed fiber interferometer (MFI) by using a tunable laser and fiber Bragg grating (FBG). The optical measurement system multiplexes two Michelson fiber interferometers with shared optical path in the main part of optical system. One fiber optic interferometer is used as a reference interferometer to monitor and control the high accuracy of the measurement system under environmental perturbations. The other is used as a measurement interferometer to obtain information from the target. An active phase tracking homodyne (APTH) technique is applied for signal processing to achieve high resolution. MFI can be utilized for high precision absolute displacement measurement with different combination of wavelengths from the tunable laser. By means of Wavelength-Division-Multiplexing (WDM) technique, MFI is also capable of realizing on-line surface measurement, in which traditional stylus scanning is replaced by spatial light-wave scanning so as to greatly improve the measurement speed and robustness.

  8. Absolute wind measurements in the lower thermosphere of Venus using infrared heterodyne spectroscopy

    NASA Technical Reports Server (NTRS)

    Goldstein, Jeffrey J.

    1990-01-01

    The first absolute wind velocities above the Venusian cloud-tops were obtained using NASA/Goddard infrared heterodyne spectrometers at the NASA Infrared Telescope Facility (IRTF) and the McMath Solar Telescope. Beam-integrated Doppler displacements in the non-thermal emission core of (12)C(16)O2 10.33 micron R(8) sampled the line of sight projection of the lower thermospheric wind field (100 to 120 km). A field-usable Lamb-dip laser stabilization system, developed for spectrometer absolute frequency calibration to less than + or - 0.1 MHz, allowed S/N-limited line of sight velocity resolution at the 1 m/s level. The spectrometer's diffraction-limited beam (1.7 arc-second HPBW at McMath, 0.9 arc-second HPBW at IRTF), and 1 to 2 arc-second seeing, provided the spatial resolution necessary for circulation model discrimination. Qualitative analysis of beam-integrated winds provided definitive evidence of a dominant subsolar-antisolar circulation in the lower thermosphere. Beam-integrated winds were modelled with a 100x100 grid over the beam, incorporating beam spatial rolloff and across-the-beam gradients in non-thermal emission intensity, line of sight projection geometry, and horizontal wind velocity. Horizontal wind velocity was derived from a 2-parameter model wind field comprised of subsolar-antisolar and zonal components. Best-fit models indicated a dominant subsolar-antisolar flow with 120 m/s cross-terminator winds and a retrograde zonal component with a 25 m/s equatorial velocity. A review of all dynamical indicators above the cloud-tops allowed development of an integrated and self-consistent picture of circulation in the 70 to 200 km range.

  9. Absolute wind measurements in the lower thermosphere of Venus using infrared heterodyne spectroscopy

    NASA Astrophysics Data System (ADS)

    Goldstein, Jeffrey J.

    1990-05-01

    The first absolute wind velocities above the Venusian cloud-tops were obtained using NASA/Goddard infrared heterodyne spectrometers at the NASA Infrared Telescope Facility (IRTF) and the McMath Solar Telescope. Beam-integrated Doppler displacements in the non-thermal emission core of (12)C(16)O2 10.33 micron R(8) sampled the line of sight projection of the lower thermospheric wind field (100 to 120 km). A field-usable Lamb-dip laser stabilization system, developed for spectrometer absolute frequency calibration to less than + or - 0.1 MHz, allowed S/N-limited line of sight velocity resolution at the 1 m/s level. The spectrometer's diffraction-limited beam (1.7 arc-second HPBW at McMath, 0.9 arc-second HPBW at IRTF), and 1 to 2 arc-second seeing, provided the spatial resolution necessary for circulation model discrimination. Qualitative analysis of beam-integrated winds provided definitive evidence of a dominant subsolar-antisolar circulation in the lower thermosphere. Beam-integrated winds were modelled with a 100x100 grid over the beam, incorporating beam spatial rolloff and across-the-beam gradients in non-thermal emission intensity, line of sight projection geometry, and horizontal wind velocity. Horizontal wind velocity was derived from a 2-parameter model wind field comprised of subsolar-antisolar and zonal components. Best-fit models indicated a dominant subsolar-antisolar flow with 120 m/s cross-terminator winds and a retrograde zonal component with a 25 m/s equatorial velocity. A review of all dynamical indicators above the cloud-tops allowed development of an integrated and self-consistent picture of circulation in the 70 to 200 km range.

  10. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  11. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  12. Measurement of absolute CO number densities in CH3F/O2 plasmas by optical emission self-actinometry

    NASA Astrophysics Data System (ADS)

    Karakas, Erdinc; Kaler, Sanbir; Lou, Qiaowei; Donnelly, Vincent M.; Economou, Demetre J.

    2014-02-01

    CH3F/O2 inductively coupled plasmas at 10 mTorr were investigated using optical emission spectroscopy. A ‘self-actinometry’ method was developed to measure the absolute number density of CO that formed in reactions following dissociation of CH3F and O2 in the plasma. In this method, small amounts of CO were added to the plasma, leading to small increases in the CO emission intensity. By carefully accounting for small perturbations to the plasma electron density and/or electron energy distribution, and by showing that very little of the CO added to the plasma was decomposed by electron impact or other reactions, it was possible to derive absolute number densities for the CO content of the plasma. With equal fractions (0.50) of CH3F and O2 in the feed gas, the CO mole fraction as a function of plasma power saturated at a value of 0.20-0.25. As O2 in the feed gas was varied at a constant power of 100 W, the CO mole fraction went through a maximum of about 0.25 near an O2 feed gas fraction of 0.5. The relative CO number densities determined by ‘standard’ actinometry followed the same functional dependence as the absolute mole fractions determined by self-actinometry, aided by the fact that electron temperature did not change appreciably with power or feed gas composition.

  13. Spatially resolved absolute diffuse reflectance measurements for noninvasive determination of the optical scattering and absorption coefficients of biological tissue

    NASA Astrophysics Data System (ADS)

    Kienle, Alwin; Lilge, Lothar; Patterson, Michael S.; Hibst, Raimund; Steiner, Rudolf; Wilson, Brian C.

    1996-05-01

    The absorption and transport scattering coefficients of biological tissues determine the radial dependence of the diffuse reflectance that is due to a point source. A system is described for making remote measurements of spatially resolved absolute diffuse reflectance and hence noninvasive, noncontact estimates of the tissue optical properties. The system incorporated a laser source and a CCD camera. Deflection of the incident beam into the camera allowed characterization of the source for absolute reflectance measurements. It is shown that an often used solution of the diffusion equation cannot be applied for these measurements. Instead, a neural network, trained on the results of Monte Carlo simulations, was used to estimate the absorption and scattering coefficients from the reflectance data. Tests on tissue-simulating phantoms with transport scattering coefficients between 0.5 and 2.0 mm-1 and absorption coefficients between 0.002 and 0.1 mm -1 showed the rms errors of this technique to be 2.6% for the transport scattering coefficient and 14% for the absorption coefficients. The optical properties of bovine muscle, adipose, and liver tissue, as well as chicken muscle (breast), were also measured ex vivo at 633 and 751 nm. For muscle tissue it was found that the Monte Carlo simulation did not agree with experimental measurements of reflectance at distances less than 2 mm from the incident beam. Carlo, neural network.

  14. In situ measurement of low-Z material coating thickness on high Z substrate for tokamaks

    SciTech Connect

    Mueller, D. Roquemore, A. L.; Jaworski, M.; Skinner, C. H.; Miller, J.; Creely, A.; Raman, P.; Ruzic, D.

    2014-11-15

    Rutherford backscattering of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an {sup 241}Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 h of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm{sup 2} thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.

  15. Analysis of variance on thickness and electrical conductivity measurements of carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Li, Min-Yang; Yang, Mingchia; Vargas, Emily; Neff, Kyle; Vanli, Arda; Liang, Richard

    2016-09-01

    One of the major challenges towards controlling the transfer of electrical and mechanical properties of nanotubes into nanocomposites is the lack of adequate measurement systems to quantify the variations in bulk properties while the nanotubes were used as the reinforcement material. In this study, we conducted one-way analysis of variance (ANOVA) on thickness and conductivity measurements. By analyzing the data collected from both experienced and inexperienced operators, we found some operation details users might overlook that resulted in variations, since conductivity measurements of CNT thin films are very sensitive to thickness measurements. In addition, we demonstrated how issues in measurements damaged samples and limited the number of replications resulting in large variations in the electrical conductivity measurement results. Based on this study, we proposed a faster, more reliable approach to measure the thickness of CNT thin films that operators can follow to make these measurement processes less dependent on operator skills.

  16. Characterization and Absolute QE Measurements of Delta-Doped N-Channel and P-Channel CCDs

    NASA Technical Reports Server (NTRS)

    Jacquot, Blake C.; Monacos, Steve P.; Jones, Todd J.; Blacksberg, Jordana; Hoenk, Michael E.; Nikzad, Shouleh

    2010-01-01

    In this paper we present the methodology for making absolute quantum efficiency (QE) measurements from the vacuum ultraviolet (VUV) through the near infrared (NIR) on delta-doped silicon CCDs. Delta-doped detectors provide an excellent platform to validate measurements through the VUV due to their enhanced UV response. The requirements for measuring QE through the VUV are more strenuous than measurements in the near UV and necessitate, among other things, the use of a vacuum monochromator, and good camera vacuum to prevent chip condensation, and more stringent handling requirements. The system used for these measurements was originally designed for deep UV characterization of CCDs for the WF/PC instrument on Hubble and later for Cassini CCDs.

  17. Absolute distance measurement by multi-heterodyne interferometry using a frequency comb and a cavity-stabilized tunable laser.

    PubMed

    Wu, Hanzhong; Zhang, Fumin; Liu, Tingyang; Balling, Petr; Qu, Xinghua

    2016-05-20

    In this paper, we develop a multi-heterodyne system capable of absolute distance measurement using a frequency comb and a tunable diode laser locked to a Fabry-Perot cavity. In a series of subsequent measurements, numerous beat components can be obtained by downconverting the optical frequency into the RF region with multi-heterodyne interferometry. The distances can be measured via the mode phases with a series of synthetic wavelengths. The comparison with the reference interferometer shows an agreement within 1.5 μm for the averages of five measurements and 2.5 μm for the single measurement, which is at the 10-8 relative precision level.

  18. Method based on chirp decomposition for dispersion mismatch compensation in precision absolute distance measurement using swept-wavelength interferometry.

    PubMed

    Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Hu, Tao; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

    2015-12-14

    We establish a theoretical model of dispersion mismatch in absolute distance measurements using swept-wavelength interferometry (SWI) and propose a novel dispersion mismatch compensation method called chirp decomposition. This method separates the dispersion coefficient and distance under test, which ensures dispersion mismatch compensation without introducing additional random errors. In the measurement of a target located at 3.9 m, a measurement resolution of 45.9 μm is obtained, which is close to the theoretical resolution, and a standard deviation of 0.74 μm is obtained, which is better than the traditional method. The measurement results are compared to a single-frequency laser interferometer. The target moves from 1 m to 3.7 m, and the measurement precision using the new method is less than 0.81 μm.

  19. Film thickness measurement for spiral groove and Rayleigh step lift pad self-acting face seals

    NASA Technical Reports Server (NTRS)

    Dirusso, E.

    1982-01-01

    One Rayleigh step lift pad and three spiral groove self-acting face seal configurations were tested to measure film thickness and frictional torque as a function of shaft speed. The seals were tested at a constant face load of 73 N (16.4 lb) with ambient air at room temperature and atmospheric pressure as the fluid medium. The test speed range was from 7000 to 17,000 rpm. The measured film thickness was compared with theoretical data from mathematical models. The mathematical models overpredicted the measured film thickness at the lower speeds of the test speed range and underpredicted the measured film thickness at the higher speeds of the test speed range.

  20. Relationship between macular thickness measurement and signal strength using Stratus optical coherence tomography

    PubMed Central

    Segal, Ori; Shapira, Yinon; Gershoni, Assaf; Vainer, Igor; Nemet, Arie Y; Geffen, Noa; Mimouni, Michael

    2016-01-01

    Purpose To examine the relationship between signal strength and macular thickness as measured by Stratus optical coherence tomography (OCT)’s fast macular thickness protocol in healthy subjects. Methods In this prospective cross-sectional study 79 eyes of 42 healthy subjects were enrolled. The age, gender, and eye (right vs left) of each subject were recorded. The Stratus OCT fast macular thickness scan protocol was used and the macular thickness was measured with retinal thickness map analysis. Each eye was imaged at least six times to acquire images with signal strengths of 4, 5, 6, 7, 8, and 9 out of 10 via adjustment of the focusing knob. The OCT parameters included in the analysis were thickness in the central 1 mm and in the different quadrants in the 3-mm area. Results Overall 79 eyes of 42 patients with a mean age of 38.4±12.4 were included. There was no significant difference between the signal strength measurements obtained with different signal strengths in the central thickness (P=0.20). In the superior, nasal, inferior, and temporal quadrants, a signal strength of 8 demonstrated up to 3 µm thicker measurements than a signal strength of 5 (P<0.05). In general linear regression analysis, after accounting for age and gender, signal strength did not remain a significant predictor of thickness in any quadrant. Conclusions When using fast map macular measurements, a signal strength of 5 is clinically as efficient as a signal strength of 8 in measuring macular thickness in all quadrants. Insisting on higher signal strength may not be necessary. PMID:27956823

  1. SU-E-T-89: Accuracy of Absolute Three-Dimensional Dose Distribution Measurement Using the Delta4

    SciTech Connect

    Uehara, R; Tachibana, H; Ohyoshi, H; Matsumoto, S; Baba, H; Tanaka, F; Ariji, T

    2015-06-15

    Purpose: In this study, we investigated the accuracy of the absolute dose distribution measurement using the Delta4 phantom compared to the measurements using a ionization chamber and EDR2 film Methods: Several conventional and intensity-modulated radiation therapy plans were used to compare the dose distribution measured using the Delta4 phantom to the absolute point dose using the chamber and the relative two-dimensional dose distribution using the EDR2 film. For the absolute dose distribution evaluation, the measurements using the Delta4, the chamber and the film were performed in similar measurement geometry. For point dose measurement using the chamber, an acrylic slab phantom with the PTW Semiflex chamber was inserted into the Delta4 phantom, alternative to the Delta4 main unit. Similarly, for dose distribution measurement using the film, the EDR2 film sandwiched with two acrylic slab phantoms were inserted to the phantom. Dose difference and gamma analysis were done for point dose and relative dose distribution comparisons, respectively. Results: The point dose measurements show slight negative systematic dose difference of −0.5 ± 0.1% and −1.0 ± 0.4% in the conventional and the IMRT plans, respectively. The additional measurement for direction dependency for Delta4 shows similar negative systematic dose difference even the phantom analysis software consider the directional dependency. The pass rate of the gamma evaluation was 77.7 ± 5.8% and 88.8±3.3% in the conventional and the IMRT plans, respectively. Conclusions: The Delta4 phantom shows a 1%-systematic dose difference derived from directional dependency and lower resolution compared to the film. Thus it is necessary to comprehensively evaluate the phantom to verify the IMRT/VMAT plans. Especially, the dosimetry tool is needed to have high resolution and high measurement accuracy in IMRT/VMAT-SBRT plan with small fields using intensity modulation in which the analysis area is limited and the

  2. Precise measurements of the absolute γ-ray emission probabilities of (223)Ra and decay progeny in equilibrium.

    PubMed

    Collins, S M; Pearce, A K; Regan, P H; Keightley, J D

    2015-08-01

    Precise measurements of the absolute γ-ray emission probabilities have been made of radiochemically pure solutions of (223)Ra in equilibrium with its decay progeny, which had been previously standardised by 4π(liquid scintillation)-γ digital coincidence counting techniques. Two high-purity germanium γ-ray spectrometers were used which had been accurately calibrated using a suite of primary and secondary radioactive standards. Comparison of the activity concentration determined by the primary technique against γ-ray spectrometry measurements using the nuclear data evaluations of the Decay Data Evaluation Project exhibited a range of ~18% in the most intense γ-ray emissions (>1% probability) of the (223)Ra decay series. Absolute γ-ray emission probabilities and standard uncertainties have been determined for the decay of (223)Ra, (219)Rn, (215)Po, (211)Pb, (211)Bi and (207)Tl in equilibrium. The standard uncertainties of the measured γ-ray emission probabilities quoted in this work show a significant improvement over previously reported γ-ray emission probabilities. Correlation coefficients for pairs of the measured γ-ray emission probabilities from the decays of the radionuclides (223)Ra, (219)Rn and (211)Pb have been determined and are presented. The α-transition probabilities of the (223)Ra have been deduced from P(γ+ce) balance using the γ-ray emission probabilities determined in this work with some agreement observed with the published experimental values of the α-emission probabilities.

  3. Repeat Absolute and Relative Gravity Measurements for Geothermal Reservoir Monitoring in the Ogiri Geothermal Field, Southern Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Nishijima, J.; Umeda, C.; Fujimitsu, Y.; Takayama, J.; Hiraga, N.; Higuchi, S.

    2016-09-01

    Repeat hybrid microgravity measurements were conducted around the Ogiri Geothermal Field on the western slope of Kirishima volcano, southern Kyushu, Japan. This study was undertaken to detect the short-term gravity change caused by the temporary shutdown of production and reinjection wells for regular maintenance in 2011 and 2013. Repeat microgravity measurements were taken using an A-10 absolute gravimeter (Micro-g LaCoste) and CG-5 gravimeter (Scintrex) before and after regular maintenance. Both instruments had an accuracy of 10 μgal. The gravity stations were established at 27 stations (two stations for absolute measurements and 25 stations for relative measurements). After removal of noise effects (e.g., tidal movement, precipitation, shallow groundwater level changes), the residual gravity changes were subdivided into five types of response. We detected a gravity decrease (up to 20 μgal) in the reinjection area and a gravity increase (up to 30 μgal) in the production area 1 month after the temporary shutdown. Most of the gravity stations recovered after the maintenance. The temporal density changes in the geothermal reservoir were estimated based on these gravity changes.

  4. Patient-specific left atrial wall-thickness measurement and visualization for radiofrequency ablation

    NASA Astrophysics Data System (ADS)

    Inoue, Jiro; Skanes, Allan C.; White, James A.; Rajchl, Martin; Drangova, Maria

    2014-03-01

    INTRODUCTION: For radiofrequency (RF) catheter ablation of the left atrium, safe and effective dosing of RF energy requires transmural left atrium ablation without injury to extra-cardiac structures. The thickness of the left atrial wall may be a key parameter in determining the appropriate amount of energy to deliver. While left atrial wall-thickness is known to exhibit inter- and intra-patient variation, this is not taken into account in the current clinical workflow. Our goal is to develop a tool for presenting patient-specific left atrial thickness information to the clinician in order to assist in the determination of the proper RF energy dose. METHODS: We use an interactive segmentation method with manual correction to segment the left atrial blood pool and heart wall from contrast-enhanced cardiac CT images. We then create a mesh from the segmented blood pool and determine the wall thickness, on a per-vertex basis, orthogonal to the mesh surface. The thickness measurement is visualized by assigning colors to the vertices of the blood pool mesh. We applied our method to 5 contrast-enhanced cardiac CT images. RESULTS: Left atrial wall-thickness measurements were generally consistent with published thickness ranges. Variations were found to exist between patients, and between regions within each patient. CONCLUSION: It is possible to visually determine areas of thick vs. thin heart wall with high resolution in a patient-specific manner.

  5. In situ method for real time measurement of dielectric film thickness in plasmas

    SciTech Connect

    Jang, Sung-Ho; Kim, Gun-Ho; Chung, Chin-Wook

    2010-01-15

    An in situ thickness measurement method of dielectric films (dual frequency method) was developed, and the thicknesses were measured in an inductively coupled plasma. This method uses a small ac bias voltage with two frequencies for thickness measurement. The dielectric thickness is obtained from measuring the amplitudes of the two frequency ac currents through a sensor, as well as using an equivalent circuit model describing impedance of the dielectric film and the plasma sheath. In the experiment, the thicknesses of Al{sub 2}O{sub 3} film could be accurately measured in real time. To check the measurement reliability, the dual frequency method was compared with reflection spectrophotometry as a technique for optical thickness diagnostics. It was found that the dual frequency method agrees closely with reflection spectrophotometry at various rf powers and pressures. In addition, this method is very simple and can be installed anywhere in plasma reactors, in contrast with optical methods; therefore, it is expected to be applied to in situ surface diagnostics for various processing plasmas.

  6. 3D absolute shape measurement of live rabbit hearts with a superfast two-frequency phase-shifting technique

    PubMed Central

    Wang, Yajun; Laughner, Jacob I.; Efimov, Igor R.; Zhang, Song

    2013-01-01

    This paper presents a two-frequency binary phase-shifting technique to measure three-dimensional (3D) absolute shape of beating rabbit hearts. Due to the low contrast of the cardiac surface, the projector and the camera must remain focused, which poses challenges for any existing binary method where the measurement accuracy is low. To conquer this challenge, this paper proposes to utilize the optimal pulse width modulation (OPWM) technique to generate high-frequency fringe patterns, and the error-diffusion dithering technique to produce low-frequency fringe patterns. Furthermore, this paper will show that fringe patterns produced with blue light provide the best quality measurements compared to fringe patterns generated with red or green light; and the minimum data acquisition speed for high quality measurements is around 800 Hz for a rabbit heart beating at 180 beats per minute. PMID:23482151

  7. Absolute measurement of the differential cross section for deuteron photodisintegration from 63 to 71 MeV

    SciTech Connect

    Debevec, P.T.; Harty, P.D.; Knott, J.E. ); Jenkins, D.A.; Jones, R.T. )

    1992-03-01

    The absolute differential cross section for the {sup 2}H({gamma},{ital p}){ital n} reaction has been measured using a large solid angle detector, with a tagged photon beam of mean energy 67 MeV. The data have been compared with nine different theoretical calculations of the cross section, which account for the data to varying degrees. Best agreement is obtained for models utilizing the nonrelativistic impulse approximation with a realistic nuclear potential, meson-exchange currents, and relativistic corrections.

  8. Measurement of the absolute vμ-CCQE cross section at the SciBooNE experiment

    SciTech Connect

    Aunion, Jose Luis Alcaraz

    2010-07-01

    This thesis presents the measurement of the charged current quasi-elastic (CCQE) neutrino-nucleon cross section at neutrino energies around 1 GeV. This measurement has two main physical motivations. On one hand, the neutrino-nucleon interactions at few GeV is a region where existing old data are sparse and with low statistics. The current measurement populates low energy regions with higher statistics and precision than previous experiments. On the other hand, the CCQE interaction is the most useful interaction in neutrino oscillation experiments. The CCQE channel is used to measure the initial and final neutrino fluxes in order to determine the neutrino fraction that disappeared. The neutrino oscillation experiments work at low neutrino energies, so precise measurement of CCQE interactions are essential for flux measurements. The main goal of this thesis is to measure the CCQE absolute neutrino cross section from the SciBooNE data. The SciBar Booster Neutrino Experiment (SciBooNE) is a neutrino and anti-neutrino scattering off experiment. The neutrino energy spectrum works at energies around 1 GeV. SciBooNE was running from June 8th 2007 to August 18th 2008. In that period, the experiment collected a total of 2.65 x 1020 protons on target (POT). This thesis has used full data collection in neutrino mode 0.99 x 1020 POT. A CCQE selection cut has been performed, achieving around 70% pure CCQE sample. A fit method has been exclusively developed to determine the absolute CCQE cross section, presenting results in a neutrino energy range from 0.2 to 2 GeV. The results are compatible with the NEUT predictions. The SciBooNE measurement has been compared with both Carbon (MiniBoonE) and deuterium (ANL and BNL) target experiments, showing a good agreement in both cases.

  9. Absolute Beam Energy Measurement using Elastic ep Scattering at Thomas Jefferson National Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre

    1999-10-01

    The Jefferson Lab beam energy measurement in Hall A using the elastic ep scattering will be described. This new, non-magnetic, energy measurement method allows a ( triangle E/E=10-4 ) precision. First-order corrections are canceled by the measurements of the electron and proton scattering angles for two symmetric kinematics. The measurement principle will be presented as well as the device and measurement results. Comparison with independent magnetic energy measurements of the same accuracy will be shown. This project is the result of a collaboration between the LPC: université Blaise Pascal/in2p3), Saclay and Jefferson Lab.

  10. Quantitative measurement of absolute cell volume and intracellular integral refractive index (RI) with dual-wavelength digital holographic microscopy (DHM)

    NASA Astrophysics Data System (ADS)

    Boss, Daniel; Kühn, Jonas; Depeursinge, Christian; Magistretti, Pierre J.; Marquet, Pierre

    2012-06-01

    Quantitative Phase Imaging techniques including DHM have been applied recently in the field of cell imaging to monitor and quantify non-invasively dynamic cellular processes modifying cell morphology and/or content . Concretely, the DHM phase signal is highly sensitive to cell thickness and intracellular integral RI variations associated with transmembrane water movements. As net water flow across the cell membrane leads at the same time to changes in cell thickness and intracellular RI, the interpretation of phase signal variations remains difficult. To overcome this drawback, we have developed a Dual-wavelength Digital Holographic Microscopy (DHM) setup allowing to separately measure, with a single CCD camera acquisition, thickness and integral RI of living cells. The method is based on the use of an absorbing dye that enhances the refractive index dispersion of the extracellular medium. Practically, two significantly different phase signals can be obtained when measuring at two appropriate wavelengths. From the two phase measurements, both cell RI and thickness can be univocally determined.

  11. Measurement of excited layer thickness in highly photo-excited GaAs

    NASA Astrophysics Data System (ADS)

    Liang, Lingliang; Tian, Jinshou; Wang, Tao; Wu, Shengli; Li, Fuli; Gao, Guilong

    2016-10-01

    Highly photo-excited layer thickness in GaAs is measured using a pump probe arrangement. A normally incident pump illumination spatially modulated by a mask will induce a corresponding refractive index change distribution in the depth direction due to edge scattering and attenuation absorption effect, which can deflect the probe beam passing through this excited region. Maximum deflection of the probe beam will be limited by the thickness of excited layer, and thus can also be employed to measure the thickness of the photo-excited layer of the material. Theoretical calculation confirms the experimental results. This method can find its application in measurements of photo-excited layer thickness of many kinds of materials and be significant to study the characteristics of materials in laser machining, grating and waveguide fabricating.

  12. On-line ultrasonic system for measuring thickness of the copper stave in the blast furnace

    NASA Astrophysics Data System (ADS)

    Choi, Sang-Woo; Kim, Dohoon

    2012-05-01

    The blast furnace is used make molten iron from sintered ore and the cokes in the steel industry. Recently, the copper stave cooling system placed on inner face of the blast furnace body to protect the steel shell from heat. In the high temperature environment, the wear between the stave and the material makes the cooling stave thinning by the downward movement of the materials in the blast furnace. It was impossible to access the copper stave with the ultrasonic sensor for measuring thickness because the copper stave is covered with the steel shell and there is backing refractory between the stave and the steel shell. The unique ultrasonic sensor which can approach the cooling stave through the cooling line was developed to measure thickness. The thickness can be measured with portable ultrasonic thickness sensor and can be monitored continuously with embedded sensors.

  13. Simultaneous measurement of thickness and refractive index using phase shifted Coherent Gradient Sensor

    NASA Astrophysics Data System (ADS)

    Disawal, Reena; Suzuki, Takamasa; Prakash, Shashi

    2016-12-01

    We report simultaneous measurement of thickness and refractive index (RI) using Coherent Gradient Sensing (CGS) based interferometric setup. The collimated light beam transmitted through the specimen is analyzed using two gratings in tandem and a spatial filtering arrangement. At the imaging plane, the desired orders superpose yielding interference fringes. Phase shifting interferometric (PSI) technique has been used to obtain the phase information directly. For decoding the information of thickness and RI, the specimen is rotated and the variation in interferometric phase before and after the specimen rotation determined. Simultaneous measurement on a glass plate of thickness 6.019 mm and refractive index of 1.4570 has been demonstrated. Detailed uncertainty analysis is also reported. The expanded uncertainty for thickness and RI in the measurement process was determined to be ±0.005 mm and ±0.00008 respectively.

  14. A Novel Portable Absolute Transient Hot-Wire Instrument for the Measurement of the Thermal Conductivity of Solids

    NASA Astrophysics Data System (ADS)

    Assael, Marc J.; Antoniadis, Konstantinos D.; Metaxa, Ifigeneia N.; Mylona, Sofia K.; Assael, John-Alexander M.; Wu, Jiangtao; Hu, Miaomiao

    2015-11-01

    A new portable absolute Transient Hot-Wire instrument for measuring the thermal conductivity of solids over a range of 0.2 { W}{\\cdot }m^{-1}{\\cdot }{K}^{-1} to 4 { W}{\\cdot }m^{-1}{\\cdot }{K}^{-1} is presented. The new instrument is characterized by three novelties: (a) an innovative two-wires sensor which provides robustness and portability, while at the same time employs a soft silicone layer to eliminate the effect of the contact resistance between the wires and the sample, (b) a newly designed compact portable printed electronic board employing an FPGA architecture CPU to the control output voltage and data processing—the new board replaces the traditional, large in size Wheatstone-type bridge system required to perform the experimental measurements, and (c) a cutting-edge software suite, developed for the mesh describing the structure of the sensor, and utilizing the Finite Elements Method to model the heat flow. The estimation of thermal conductivity is modeled as a minimization problem and is solved using Bayesian Optimization. Our revolutionizing proposed methodology exhibits radical speedups of up to × 120, compared to previous approaches, and considerably reduces the number of simulations performed, achieving convergence only in a few minutes. The new instrument was successfully employed to measure, at room temperature, the thermal conductivity of two thermal conductivity reference materials, Pyroceram 9606 and Pyrex 7740, and two possible candidate glassy solids, PMMA and BK7, with an absolute low uncertainty of 2 %.

  15. Radiometric absolute noise-temperature measurement system features improved accuracy and calibration ease

    NASA Technical Reports Server (NTRS)

    Brown, W.; Ewen, H.; Haroules, G.

    1970-01-01

    Radiometric receiver system, which measures noise temperatures in degrees Kelvin, does not require cryogenic noise sources for routine operation. It eliminates radiometer calibration errors associated with RF attenuation measurements. Calibrated noise source is required only for laboratory adjustment and calibration.

  16. Absolute prompt-gamma yield measurements for ion beam therapy monitoring

    NASA Astrophysics Data System (ADS)

    Pinto, M.; Bajard, M.; Brons, S.; Chevallier, M.; Dauvergne, D.; Dedes, G.; De Rydt, M.; Freud, N.; Krimmer, J.; La Tessa, C.; Létang, J. M.; Parodi, K.; Pleskač, R.; Prieels, D.; Ray, C.; Rinaldi, I.; Roellinghoff, F.; Schardt, D.; Testa, E.; Testa, M.

    2015-01-01

    Prompt-gamma emission detection is a promising technique for hadrontherapy monitoring purposes. In this regard, obtaining prompt-gamma yields that can be used to develop monitoring systems based on this principle is of utmost importance since any camera design must cope with the available signal. Herein, a comprehensive study of the data from ten single-slit experiments is presented, five consisting in the irradiation of either PMMA or water targets with lower and higher energy carbon ions, and another five experiments using PMMA targets and proton beams. Analysis techniques such as background subtraction methods, geometrical normalization, and systematic uncertainty estimation were applied to the data in order to obtain absolute prompt-gamma yields in units of prompt-gamma counts per incident ion, unit of field of view, and unit of solid angle. At the entrance of a PMMA target, where the contribution of secondary nuclear reactions is negligible, prompt-gamma counts per incident ion, per millimetre and per steradian equal to (124 ± 0.7stat ± 30sys) × 10-6 for 95 MeV u-1 carbon ions, (79 ± 2stat ± 23sys) × 10-6 for 310 MeV u-1 carbon ions, and (16 ± 0.07stat ± 1sys) × 10-6 for 160 MeV protons were found for prompt gammas with energies higher than 1 MeV. This shows a factor 5 between the yields of two different ions species with the same range in water (160 MeV protons and 310 MeV u-1 carbon ions). The target composition was also found to influence the prompt-gamma yield since, for 300/310 MeV u-1 carbon ions, a 42% greater yield ((112 ± 1stat ± 22sys) × 10-6 counts ion-1 mm-1 sr-1) was obtained with a water target compared to a PMMA one.

  17. Excess fraction measurement of a transparent glass thickness in wavelength tuning interferometry

    NASA Astrophysics Data System (ADS)

    Kim, Yangjin; Hibino, Kenichi; Harada, Kanako; Sugita, Naohiko; Mitsuishi, Mamoru

    2013-04-01

    The interference fringe order of a transparent glass plate was determined using a three-surface wavelength-tuning Fizeau interferometer and an excess fraction method. We employed multiple-surface interferometry considering the potential for simultaneous measurement of the surface shape and geometric thickness. The optical thickness signal was separated from the three interference signals in the frequency space. A frequency selective phase-shifting algorithm and a discrete Fourier analysis detected the phase of the modulated interference fringes. The optical thickness obtained by wavelengthtuning Fizeau interferometry is related to the group refractive index. In contrast, the optical thickness deviation obtained by the phase-shifting technique is related to the ordinary refractive index. These two kinds of optical thicknesses were synthesized with the help of the dispersion relation of a fused-silica glass. Finally, the interference fringe order was determined using an excess fraction method that could eliminate the initial uncertainty of the refractive index.

  18. Thickness dependent CARS measurement of polymeric thin films without depth-profiling.

    PubMed

    Choi, Dae Sik; Jeoung, Sae Chae; Chon, Byung-Hyuk

    2008-02-18

    Coherent anti-Stokes Raman scattering (CARS) microscopy is demonstrated to be a promising optical method for the characterization of polymer films with film thickness varying between 180 nm to 4300 nm. In case of PMMA films with a thickness of few hundreds of nanometers, the observed CARS signal was mainly associated with the interference effect of large nonresonant CARS field from glass substrate and the weak resonant field of PMMA. The dependence of resonant CARS intensity of PMMA film on film thickness is in good agreement with the theoretical prediction on a CARS field. The current work offers potential possibilities of noninvasive thickness measurement of polymeric thin film of thickness less than 180 nm by multiplex CARS microscopy without depth-profiling.

  19. Research on measurement of center thickness of the lens with a hole

    NASA Astrophysics Data System (ADS)

    Zhang, Linchao; Wu, Xiaoming; Li, Haozhao; Sun, Hongxiao

    2016-09-01

    In the field of modern optical measurement, the center thickness is a basic parameter of the optical lens, which will directly, affects the accuracy of the lens' focal length and other optical parameters, and these parameters have great influence on overall performance of the optical system. Therefore center thickness requires precision test. Nowadays, the methods include contact measurement and non-contact measurement. Generally speaking, the center thickness of the lens with no hole in the center only could be measured through the both methods. The lens with a hole in the center is used widely, on the basis of principle of contact measurement, a method of measuring center thickness of the lens with a hole is proposed. A sign convention about radius and sagitta of curvature is defined and the geometrical expressions are derived in detail. Analyses and simulations between the errors of center thickness and variables are shown. To prove the right of the method, an experiment is done in use of a lens with no hole in the center. The results of indirect and direct measurements are presented, respectively. In comparison of direct measurement, the proposed method has a high precision.

  20. An absolute radon 222 activity measurement system at LNE-LNHB.

    PubMed

    Sabot, B; Pierre, S; Cassette, P

    2016-12-01

    A good metrological traceability of radon and progenies is necessary to accurately measure the radon concentration. In 1995, at the LNE-LNHB, J.L. Picolo developed a reference method using a defined-solid-angle (DSA) alpha spectrometer to measure a frozen radon source. With this method it was possible to measure radon standards with a relative standard uncertainty of 0.5%. This paper presents the design and the characterization of a new upgraded measurement system; all parameters and their uncertainties are discussed. This new system allows the measurement of radon sources from 100Bq to 4MBq with a relative standard uncertainty of 0.3%.

  1. Absolute Steady-State Thermal Conductivity Measurements by Use of a Transient Hot-Wire System.

    PubMed

    Roder, H M; Perkins, R A; Laesecke, A; Nieto de Castro, C A

    2000-01-01

    A transient hot-wire apparatus was used to measure the thermal conductivity of argon with both steady-state and transient methods. The effects of wire diameter, eccentricity of the wire in the cavity, axial conduction, and natural convection were accounted for in the analysis of the steady-state measurements. Based on measurements on argon, the relative uncertainty at the 95 % level of confidence of the new steady-state measurements is 2 % at low densities. Using the same hot wires, the relative uncertainty of the transient measurements is 1 % at the 95 % level of confidence. This is the first report of thermal conductivity measurements made by two different methods in the same apparatus. The steady-state method is shown to complement normal transient measurements at low densities, particularly for fluids where the thermophysical properties at low densities are not known with high accuracy.

  2. Enhanced quantitative confocal microscopy and its application for the measurement of tympanic membrane thickness

    NASA Astrophysics Data System (ADS)

    Kuypers, Liesbeth

    2005-11-01

    This work shows that confocal microscopy allows a quantitative study of delicate 3D-biotissue in fresh condition, thus avoiding histological preparation processes. The developed procedure results in exact and accurate thickness data for mum-sized objects with a measuring error of less than 1mum. It is, however, necessary to take into account the effect of focal shift in the case of refractive index mismatch to obtain such precise data. The use of the proposed method is advised instead of the use of a paraxial approximation for the axial scale correction because the method improves measurement precision by a factor of four. The axial scaling correction factors obtained in this work show that for most practical situations the correction cannot be ignored when one wants to obtain precise quantitative data. The thickness correction method can also be used to determine with high accuracy the index of refraction of biological tissue. The thickness measurement method was applied to fresh, untreated tympanic membranes of the gerbil, the cat and the human. Thickness had to be measured at many points as it differs strongly across the membrane. Similar thickness distributions were found in all pars tensas measured even across the species studied: (1) a very thin, central region with a rather constant thickness, curving as a horse shoe upwards around the manubrium (thickness: gerbil: about 7mum, cat: about 10mum, human: large inter-specimen variation: 40mum-120mum), (2) a thinnest zone at the inferior side, (3) a thicker zone at the supero-anterior side, (4) superior to the umbo, an anterior region thicker than the posterior region, (5) maximal thicknesses in a very small region near the entire manubrium and the entire annular periphery. The pars flaccida is found to be thicker than the pars tensa. It shows no central homogeneous zone: the thickness varies irregularly and very rapidly over short distances. Arbitrarily spaced bumps and notches are present over the entire pars

  3. Contactless thickness measurement of micromachined silicon sensors with transmitted infrared light

    NASA Astrophysics Data System (ADS)

    Samek, Norbert E.

    Relative transmission of infrared light has been used to measure thickness of micromachined silicon diaphragm sensors. The transmission was measured on an infrared microscope equipped with a water cooled illuminator and with 800 nm and 900 nm narrow band pass filters. Calibration tests were made by plotting the output of a photodetector on a 0 to 100 scale against the thickness of the sensors measured with an electronic dial gage. The results are compared against theoretical relative transmission curves. Factors affecting accuracy and the measuring error band are discussed.

  4. A lidar system for remote measurement of oil film thickness on sea surface

    SciTech Connect

    Piskozub, J.; Drozdowska, V.; Varlamov, V.

    1997-06-01

    A new lidar system FLS-UV designed for measurement of oil film thickness is described. The system consisting of solid state 299 nm laser and a multichannel spectral receiver was produced by LDI Ltd, Tallinn Estonia in close collaboration with Laser Laboratory of Institute of Oceanology, Sopot, Poland. The system is able to measure oil film thickness in the range of 0.5 - 10 micrometers. It utilizes two methods: light absorption of Raman band in UV and measurement of fluorescence band intensity. The system is designed for continuous measurement from ship or low altitude aircraft. Technical description of the system as well as first experimental results are presented.

  5. A laser reflectometry technique for on-device coating thickness measurements

    NASA Astrophysics Data System (ADS)

    Morris, Stephen J.

    2010-02-01

    We demonstrate the use of Beam Profile Reflectometry (BPR) to measure coating thicknesses on small, highly curved devices such as cardiac stents. BPR has long been used in the semiconductor industry as a powerful technique for measuring the thickness and refractive index of transparent films. The method uses a diffraction-limited focused laser beam to provide light at multiple angles-of-incidence simultaneously within a sub-micron measurement area. By analyzing the reflected light as a function of angle-of-incidence and polarization, robust and deterministic measurements of film-thickness and refractive index can be obtained taking proper account of birefringence. For the current work, the technique has been implemented in a compact desktop configuration suitable, for example, for the in-line monitoring of coating thickness and composition as part of a stent manufacturing process. Provision is made for the alignment and manipulation of the small and fragile samples, and for the location of the measurement spot at the appropriate site on the stent's surface. Validation measurements on stent-like reference samples, comparing results from the technique with destructive measurements on the same samples, show correlation of better than 99% over a range of coating thicknesses and sample morphologies down to curvature radii of ~50μm.

  6. Ultrasonographic measurement of the axillary recess thickness in an asymptomatic shoulder

    PubMed Central

    2017-01-01

    Purpose The purpose of this study was to measure the axillary recess (AR) thickness in an asymptomatic shoulder by using ultrasonography (US) and to analyze the factors affecting it. Methods We recruited 141 patients (52 males; 89 females; age, 57.7±9.9 years) with unilateral shoulder pain and performed US on the unaffected shoulder. Two physiatrists measured the AR thickness of the unaffected shoulder independently. All patients were examined in an upright sitting position with 90° shoulder abduction. The ultrasonographic transducer was placed longitudinally on the mid-axillary line and along the long axis of the humeral shaft. The factors affecting the AR thickness values were analyzed, and intra-class correlation coefficients were used for assessing the reproducibility of each measurement. Results The intrarater reliability values for the two physiatrists were 0.98 and 0.96, respectively. The inter-rater reliability of the mean AR thickness measurements was 0.91. The mean AR thickness in all subjects, males, and females was 2.8±0.6 mm, 3.1±0.6 mm, and 2.6±0.5 mm (P<0.01), respectively. No difference between the left and the right sides (males, P=0.086; females, P=0.535) or between the dominant and the non-dominant sides (males, P=0.173; female, P=0.244) was found. The AR thickness correlated positively with the height (r=0.313, P<0.01) and the weight (r=0.319, P<0.01). However, it did not correlate with the body mass index (r=0.152, P=0.077) or the age (r=-0.056, P=0.515). Conclusion US measurements of the AR thickness in asymptomatic shoulders demonstrated excellent intrarater and inter-rater reliabilities. The AR thickness showed anatomical variation with sex, height, and weight. PMID:27764911

  7. White-light scanning fiber Michelson interferometer for absolute position-distance measurement.

    PubMed

    Li, T; Wang, A; Murphy, K; Claus, R

    1995-04-01

    A white-light fiber interferometer working in the spatial domain, using two fiber ends in a hollow tube as the sensing head and an electric magnetic actuator-mirror reflector as the path-compensation-measurement element, is presented. Analysis and preliminary experiments have demonstrated a repeatability of 0.5 microm (2sigma) for position-distance measurement, and the measurement uncertainty was estimated to be 1.5 microm (2sigma) over a distance range of 150 microm. Suggestions for further improving the measurement accuracy and response speed are also given.

  8. White-light scanning fiber Michelson interferometer for absolute position-distance measurement

    NASA Astrophysics Data System (ADS)

    Li, Tianchu; Wang, Anbo; Murphy, Kent; Claus, Richard

    1995-04-01

    A white-light fiber interferometer working in the spatial domain, using two fiber ends in a hollow tube as the sensing head and an electric magnetic actuator-mirror reflector as the path-compensation-measurement element, is presented. Analysis and preliminary experiments have demonstrated a repeatability of 0.5 mu m (2 sigma ) for position-distance measurement, and the measurement uncertainty was estimated to be 1.5 mu m (2 sigma ) over a distance range of 150 mu m. Suggestions for further improving the measurement accuracy and response speed are also given.

  9. Absolute prompt-gamma yield measurements for ion beam therapy monitoring.

    PubMed

    Pinto, M; Bajard, M; Brons, S; Chevallier, M; Dauvergne, D; Dedes, G; De Rydt, M; Freud, N; Krimmer, J; La Tessa, C; Létang, J M; Parodi, K; Pleskač, R; Prieels, D; Ray, C; Rinaldi, I; Roellinghoff, F; Schardt, D; Testa, E; Testa, M

    2015-01-21

    Prompt-gamma emission detection is a promising technique for hadrontherapy monitoring purposes. In this regard, obtaining prompt-gamma yields that can be used to develop monitoring systems based on this principle is of utmost importance since any camera design must cope with the available signal. Herein, a comprehensive study of the data from ten single-slit experiments is presented, five consisting in the irradiation of either PMMA or water targets with lower and higher energy carbon ions, and another five experiments using PMMA targets and proton beams. Analysis techniques such as background subtraction methods, geometrical normalization, and systematic uncertainty estimation were applied to the data in order to obtain absolute prompt-gamma yields in units of prompt-gamma counts per incident ion, unit of field of view, and unit of solid angle. At the entrance of a PMMA target, where the contribution of secondary nuclear reactions is negligible, prompt-gamma counts per incident ion, per millimetre and per steradian equal to (124 ± 0.7stat ± 30sys) × 10(-6) for 95 MeV u(-1) carbon ions, (79 ± 2stat ± 23sys) × 10(-6) for 310 MeV u(-1) carbon ions, and (16 ± 0.07stat ± 1sys) × 10(-6) for 160 MeV protons were found for prompt gammas with energies higher than 1 MeV. This shows a factor 5 between the yields of two different ions species with the same range in water (160 MeV protons and 310 MeV u(-1) carbon ions). The target composition was also found to influence the prompt-gamma yield since, for 300/310 MeV u(-1) carbon ions, a 42% greater yield ((112 ± 1stat ± 22sys) × 10(-6) counts ion(-1) mm(-1) sr(-1)) was obtained with a water target compared to a PMMA one.

  10. Measurements of absolute total and partial cross sections for the electron ionization of tungsten hexafluoride (WF6)

    NASA Astrophysics Data System (ADS)

    Basner, R.; Schmidt, M.; Becker, K.

    2004-04-01

    We measured absolute partial cross sections for the formation of positive ions followed by electron impact on tungsten hexafluoride (WF6) from threshold to 900 eV using a time-of-flight mass spectrometer (TOF-MS). Dissociative ionization processes resulting in seven different singly charged ions (F+, W+, WFx+, x=1-5) and five doubly charged ions (W2+, WFx2+, x=1-4) were found to be the dominant ionization channels. The ion spectrum at all impact energies is dominated by WF5+ fragment ions. At 120 eV impact energy, the partial WF5+ ionization cross section has a maximum value of 3.92×10-16 cm2 that corresponds to 43% of the total ion yield. The cross section values of all the other singly charged fragment ions at 120 eV range between 0.39×10-16 and 0.73×10-16 cm2. The ionization cross sections of the doubly charged ions are more than one order of magnitude lower than the cross section of WF5+. Double ionization processes account for 21% of the total ion yield at 120 eV. The absolute total ionization cross section of WF6 was obtained as the sum of all measured partial ionization cross sections and is compared with available calculated cross sections.

  11. Retinal Fibre Layer Thickness Measurement in Normal Paediatric Population in Sweden Using Optical Coherence Tomography

    PubMed Central

    Ntoula, Evangelia

    2016-01-01

    Purpose. To evaluate the correlation between peripapillary retinal nerve fibre layer (RNFL) thickness and both age and refraction error in healthy children using optical coherence tomography (OCT). Patients and Methods. 80 healthy children with a mean age of 9.1 years (range 3.8 to 16.7 years) undergoing routine ocular examination at the orthoptic section of the Ophthalmology Department were recruited for this cross-sectional study. After applying cycloplegia, the peripapillary RNFL thickness was measured in both eyes using the Topcon 3D OCT 2000 device. Results. 138 eyes were included in the analysis. The average refractive error (SE) was +1.7 D (range −5.25 to +7.25 D). The mean total RNFL thickness was 105 μm ± 10.3, the mean superior RNFL thickness was 112.7 μm ± 16.5, and the mean inferior RNFL thickness was 132.6 μm ± 18.3. We found no statistically significant effect of age on RNFL thickness (ANOVA, f = 0.33, p = 0.56). Refraction was proven to have a statistically significant effect (ANOVA, f = 67.1, p < 0.05) in RNFL measurements. Conclusions. Data obtained from this study may assist in establishing a normative database for a paediatric population. Refraction error should be taken into consideration due to its statistically significant correlation with RNFL thickness. PMID:27980862

  12. Application of Fresnel diffraction from a phase step to the measurement of film thickness

    SciTech Connect

    Taghi Tavassoly, Mohammad; Moaddel Haghighi, Iman; Hassani, Khosrow

    2009-10-10

    When a thin film that is prepared in a step form on a substrate and coated uniformly with a reflective material is illuminated by a parallel coherent beam of monochromatic light, the Fresnel diffraction fringes are formed on a screen perpendicular to the reflected beam. The visibility of the fringes depends on film thickness, angle of incidence, and light wavelength. Measuring visibility versus incident angle provides the film thickness with an accuracy of a few nanometers. The technique is easily applicable and it covers a wide range of thicknesses with highly reliable results.

  13. Application of Fresnel diffraction from a phase step to the measurement of film thickness.

    PubMed

    Taghi Tavassoly, Mohammad; Moaddel Haghighi, Iman; Hassani, Khosrow

    2009-10-10

    When a thin film that is prepared in a step form on a substrate and coated uniformly with a reflective material is illuminated by a parallel coherent beam of monochromatic light, the Fresnel diffraction fringes are formed on a screen perpendicular to the reflected beam. The visibility of the fringes depends on film thickness, angle of incidence, and light wavelength. Measuring visibility versus incident angle provides the film thickness with an accuracy of a few nanometers. The technique is easily applicable and it covers a wide range of thicknesses with highly reliable results.

  14. Automatic airway wall segmentation and thickness measurement for long-range optical coherence tomography images.

    PubMed

    Qi, Li; Huang, Shenghai; Heidari, Andrew E; Dai, Cuixia; Zhu, Jiang; Zhang, Xuping; Chen, Zhongping

    2015-12-28

    We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with sheep airway OCT images. Quantitative thicknesses of the mucosal layers are obtained automatically for smoke inhalation injury experiments.

  15. Ultrasonographic Measurement of the Thickness of Axillary Recess Capsule in Healthy Volunteers

    PubMed Central

    2016-01-01

    Objective To evaluate the inter-rater and intra-rater reliability of ultrasonographic measurements of axillary recess (AR) thickness in healthy individuals, and to analyze the factors affecting the thickness of the AR capsule. Methods We recruited 20 healthy individuals (10 male, 10 female) with a mean age of 37 years (standard deviation ±10). Two physiatrists (an experienced and a novice rater) independently investigated the AR thickness in three rounds. The AR thickness was measured for each individual at three shoulder abduction angles (50°, 70°, and 90°). Intra-class correlation (ICC) coefficients were used to assess the reproducibility of each measurement. Results Excellent intra-rater reliability coefficients were observed at the three shoulder abduction angles, in the analysis of both raters. The inter-rater reliability coefficient was also was excellent in both studies. There were significant differences in the AR thickness, according to the angle of shoulder abduction. The AR was thicker at 50° than at 70° and 90° (all p<0.001), and the AR was thicker at 70° than at 90° (p<0.001). Height (r=0.62, p=0.003) and body mass index (r=0.52, p=0.019) were positively correlated with AR thickness. Males had a thicker AR capsule than females at all three angles (all p<0.001). Conclusion Ultrasonographic measurements of AR thickness in healthy individuals demonstrate excellent intra-rater and inter-rater reliability. AR thickness may depend on anthropometric variables and position of the shoulder. PMID:27446788

  16. Measurements of absolute delayed neutron yield and group constants in the fast fission of {sup 235}U and {sup 237}Np

    SciTech Connect

    Loaiza, D.J.; Brunson, G.; Sanchez, R.; Butterfield, K.

    1998-03-01

    The delayed neutron activity resulting from the fast induced fission of {sup 235}U and {sup 237}Np has been studied. The six-group decay constants, relative abundances, and absolute yield of delayed neutrons from fast fission of {sup 235}U and {sup 237}Np were measured using the Godiva IV fast assembly at the Los Alamos Critical Experiments Facility. The absolute yield measured for {sup 235}U was 0.0163 {+-} 0.0008 neutron/fission. This value compares very well with the well-established Keepin absolute yield of 0.0165 {+-} 0.0005. The absolute yield value measured for {sup 237}Np was 0.0126 {+-} 0.0007. The measured delayed neutron parameters for {sup 235}U are corroborated with period (e-folding time) versus reactivity calculations.

  17. Using absolute x-ray spectral measurements to infer stagnation conditions in ICF implosions

    NASA Astrophysics Data System (ADS)

    Patel, Pravesh; Benedetti, L. R.; Cerjan, C.; Clark, D. S.; Hurricane, O. A.; Izumi, N.; Jarrott, L. C.; Khan, S.; Kritcher, A. L.; Ma, T.; Macphee, A. G.; Landen, O.; Spears, B. K.; Springer, P. T.

    2016-10-01

    Measurements of the continuum x-ray spectrum emitted from the hot-spot of an ICF implosion can be used to infer a number thermodynamic properties at stagnation including temperature, pressure, and hot-spot mix. In deuterium-tritium (DT) layered implosion experiments on the National Ignition Facility (NIF) we field a number of x-ray diagnostics that provide spatial, temporal, and spectrally-resolved measurements of the radiated x-ray emission. We report on analysis of these measurements using a 1-D hot-spot model to infer thermodynamic properties at stagnation. We compare these to similar properties that can be derived from DT fusion neutron measurements. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Calibration of the Odyssey Photosynthetic Irradiance Recorder for Absolute Irradiance Measures

    EPA Science Inventory

    Researchers are increasingly interested in measuring hotosynthetically active radiation (PAR) because of its importance in determining the structure and function of lotic ecosystems. The Odyssey Photosynthetic Irradiance Recorder is an affordable PAR meter gaining popularity am...

  19. Snow thickness retrieval using SMOS satellite data: Comparison with airborne IceBridge and buoy measurements

    NASA Astrophysics Data System (ADS)

    Maaß, N.; Kaleschke, L.; Tian-Kunze, X.

    2015-12-01

    The passive microwave mission SMOS (Soil Moisture and Ocean Salinity) provides daily coverage of the polar regions and its data have been used to retrieve thin sea ice thickness up to about one meter. In addition, there has been an attempt to retrieve snow thickness over thick Arctic multi-year ice, which is a crucial parameter for the freeboard-based estimation of (thick) sea ice thickness from lidar and radar altimetry. SMOS provides measurements at a frequency of 1.4 GHz (L-band) at horizontal and vertical polarization for a range of incidence angles (0 to 60°). The retrieval of ice or snow parameters from SMOS measurements is based on an emission model that describes the 1.4 GHz brightness temperature of (snow-covered) sea ice as a function of the ice and snow thicknesses and the permittivities of these media, which are mainly determined by ice temperature and salinity and snow density, respectively. In the first attempts to retrieve snow thickness from SMOS data, these parameters were assumed to be constant in the emission model, and the resulting maps were compared with airborne ice and snow thickness measurements taken during NASA's Operation IceBridge mission in spring 2012. The present approach to produce SMOS snow thickness maps is more elaborate. For example, available information on the ice surface temperature from MODIS (MODerate resolution Imaging Spectroradiometer) satellite images or from the IceBridge campaign itself are used, and the ice in the retrieval model is described by temperature and salinity profiles instead of using bulk values. As a first step we have produced (winter/spring) snow thickness maps of the Arctic, from 3-day-averages up to monthly means, using the available SMOS data from 2010 on. Here, we show how our spatial snow thickness distributions compare with IceBridge campaign data in the western Arctic from spring 2011 to 2015. In addition, we show how the temporal evolution of SMOS-retrieved snow thickness compares with snow

  20. Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea

    PubMed Central

    Clement, Colin I.; Parker, Douglas G.A.; Goldberg, Ivan

    2016-01-01

    Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics. Dynamic contour tonometry, rebound tonometry and the ocular response analyzer provide useful alternatives to GAT in patients with abnormal corneas, such as those who have undergone laser vision correction or keratoplasty. This article reviews the various methods of intra-ocular pressure measurement available to the clinician and the ways in which their utility is influenced by variations in corneal thickness and biomechanics. PMID:27014386

  1. Thickness measurement system for transparent plates using dual digital versatile disc (DVD) pickups.

    PubMed

    Liu, Chien-Hung; Yeh, Shien-Chang; Huang, Hsueh-Liang

    2010-02-01

    A low-cost high-precision thickness measurement system for transparent plates that uses dual digital versatile disc (DVD) pickups is proposed. The two DVD pickups are used as the transmitter and the receiver in the measurement system, respectively. One of the DVD pickups emits a laser to the other DVD pickup (receiver) and projects on the photodiode integrated circuit of the receiver. The transparent plate is placed in the optical path to change the focused point that will affect the focusing error signal (FES) of the receiver. Using the FES, a mathematical model for thickness measurement based on the geometric optical method is developed. The experimental results show that the accuracy is 1.5 microm, and the uncertainty is estimated to be +/-1.37 microm for the measured thickness of 150 microm.

  2. Thickness measurement system for transparent plates using dual digital versatile disc (DVD) pickups

    SciTech Connect

    Liu, Chien-Hung; Yeh, Shien-Chang; Huang, Hsueh-Liang

    2010-02-01

    A low-cost high-precision thickness measurement system for transparent plates that uses dual digital versatile disc (DVD) pickups is proposed. The two DVD pickups are used as the transmitter and the receiver in the measurement system, respectively. One of the DVD pickups emits a laser to the other DVD pickup (receiver) and projects on the photodiode integrated circuit of the receiver. The transparent plate is placed in the optical path to change the focused point that will affect the focusing error signal (FES) of the receiver. Using the FES, a mathematical model for thickness measurement based on the geometric optical method is developed. The experimental results show that the accuracy is 1.5 {mu}m, and the uncertainty is estimated to be {+-}1.37 {mu}m for the measured thickness of 150{mu}m.

  3. Solid-state track recorder dosimetry device to measure absolute reaction rates and neutron fluence as a function of time

    DOEpatents

    Gold, Raymond; Roberts, James H.

    1989-01-01

    A solid state track recording type dosimeter is disclosed to measure the time dependence of the absolute fission rates of nuclides or neutron fluence over a period of time. In a primary species an inner recording drum is rotatably contained within an exterior housing drum that defines a series of collimating slit apertures overlying windows defined in the stationary drum through which radiation can enter. Film type solid state track recorders are positioned circumferentially about the surface of the internal recording drum to record such radiation or its secondary products during relative rotation of the two elements. In another species both the recording element and the aperture element assume the configuration of adjacent disks. Based on slit size of apertures and relative rotational velocity of the inner drum, radiation parameters within a test area may be measured as a function of time and spectra deduced therefrom.

  4. Absolute depth-dose-rate measurements for an 192Ir HDR brachytherapy source in water using MOSFET detectors.

    PubMed

    Zilio, Valéry Olivier; Joneja, Om Parkash; Popowski, Youri; Rosenfeld, Anatoly; Chawla, Rakesh

    2006-06-01

    Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an 192Ir source. Measured radial dose rate distributions in water for different planes perpendicular to the source axis are presented and special attention is paid to the calibration of the R and K type detectors, and to the determination of appropriate correction factors for the sensitivity variation with the increase of the threshold voltage and the energy dependence. The experimental results are compared with Monte Carlo simulated dose rate distributions. The experimental results show a good agreement with the Monte Carlo simulations: the discrepancy between experimental and Monte Carlo results being within 5% for 82% of the points and within 10% for 95% of the points. Moreover, all points except two are found to lie within the experimental uncertainties, confirming thereby the quality of the results obtained.

  5. Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata

    NASA Astrophysics Data System (ADS)

    Som, Sumit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Duttagupta, Anjan

    2013-02-01

    Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.20, respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ("Dee" voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTe X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result.

  6. Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata.

    PubMed

    Som, Sumit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Duttagupta, Anjan

    2013-02-01

    Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.2(0), respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ("Dee" voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTe X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result.

  7. Capture time versus barrier thickness in quantum-well structures measured by infrared photoconductive gain

    NASA Astrophysics Data System (ADS)

    Rosencher, E.; Luc, F.; Bois, P.; Nagle, J.; Cordier, Y.

    1993-12-01

    Photoconductive gain measurements in quantum-well (QW) infrared detectors are used to determine the variation of the capture time of electrons in QWs as a function of barrier thickness. The capture time is shown to be proportional to the multi-quantum-well period, which is consistent with a quantum mechanical description of the capture process. The measured values are far higher than the ones measured by time-resolved photoluminescence, ranging from 8 to 150 ps, depending on the applied electric field and barrier thickness. The reasons for this discrepancy are discussed.

  8. Measurements of strip dipole antennas on finite-thickness substrates at 230 GHz

    NASA Astrophysics Data System (ADS)

    Gouker, Mark A.; Smith, Glenn S.

    1992-02-01

    Gain and field pattern measurements at 230 GHz are reported for strip dipole antennas on finite-thickness substrates without ground planes. Four substrate thicknesses are investigated ranging from 0.25 lambda to 1.53 lambda (lambda = wavelength in substrate material). Measured results are in good agreement with theoretical predictions. A unique detector/low-pass filter design, composed of a bolometer and an interdigitated capacitor, is used to eliminate the distortion of the measured field patterns caused by the reception of the leads connecting the antenna with the monitoring instrumentation.

  9. Absolute three-dimensional micro surface profile measurement based on a Greenough-type stereomicroscope

    NASA Astrophysics Data System (ADS)

    Hu, Yan; Chen, Qian; Tao, Tianyang; Li, Hui; Zuo, Chao

    2017-04-01

    Fringe projection profilometry has become a widely used method in 3D shape measurement and 3D data acquisition for the features of flexibility, noncontactness, and high accuracy. By combining fringe projection setup with microscopic optics, the fringe pattern can be projected and imaged within a small area, making it possible for measuring 3D surfaces of micro-components. In this paper, a Greenough-type stereomicroscope arrangement is firstly applied for this situation by using the two totally separated and coaxial optical paths of the stereomicroscope. The calibration framework of the stereomicroscope-based system is proposed, which enables high-accuracy calibration of the optical setup for quantitative measurement with the effect of lens distortion eliminated. In the process of 3D reconstruction, depth information is firstly retrieved through the phase-height relation calibrated by a nonlinear fitting algorithm, and the transverse position can be subsequently obtained by solving the equations derived from the calibrated model of the camera. Experiments of both calibration and measurements are conducted and the results reveal that our system is capable of conducting fully automated 3D measurements with a depth accuracy of approximately 4 μm in a volume of approximately 8(L) mm  ×  6(W) mm  ×  3(H) mm.

  10. TU-A-12A-09: Absolute Blood Flow Measurement in a Cardiac Phantom Using Low Dose CT

    SciTech Connect

    Ziemer, B; Hubbard, L; Lipinski, J; Molloi, S

    2014-06-15

    Purpose: To investigate a first pass analysis technique to measure absolute flow from low dose CT images in a cardiac phantom. This technique can be combined with a myocardial mass assignment to yield absolute perfusion using only two volume scans and reduce the radiation dose to the patient. Methods: A four-chamber cardiac phantom and perfusion chamber were constructed from poly-acrylic and connected with tubing to approximate anatomical features. The system was connected to a pulsatile pump, input/output reservoirs and power contrast injector. Flow was varied in the range of 1-2.67 mL/s with the pump operating at 60 beats/min. The system was imaged once a second for 14 seconds with a 320-row scanner (Toshiba Medical Systems) using a contrast-enhanced, prospective-gated cardiac perfusion protocol. Flow was calculated by the following steps: subsequent images of the perfusion volume were subtracted to find the contrast entering the volume; this was normalized by an upstream, known volume region to convert Hounsfield (HU) values to concentration; this was divided by the subtracted images time difference. The technique requires a relatively stable input contrast concentration and no contrast can leave the perfusion volume before the flow measurement is completed. Results: The flow calculated from the images showed an excellent correlation with the known rates. The data was fit to a linear function with slope 1.03, intercept 0.02 and an R{sup 2} value of 0.99. The average root mean square (RMS) error was 0.15 mL/s and the average standard deviation was 0.14 mL/s. The flow rate was stable within 7.7% across the full scan and served to validate model assumptions. Conclusion: Accurate, absolute flow rates were measured from CT images using a conservation of mass model. Measurements can be made using two volume scans which can substantially reduce the radiation dose compared with current dynamic perfusion techniques.

  11. Automated segmentation of intraretinal layers from spectral-domain macular OCT: reproducibility of layer thickness measurements

    NASA Astrophysics Data System (ADS)

    Lee, Kyungmoo; Abràmoff, Michael D.; Sonka, Milan; Garvin, Mona K.

    2011-03-01

    Changes in intraretinal layer thickness occur in a variety of diseases such as glaucoma, macular edema and diabetes. To segment the intraretinal layers from macular spectral-domain OCT (SD-OCT) scans, we previously introduced an automated multiscale 3-D graph search method and validated its performance by computing unsigned border positioning differences when compared with human expert tracings. However, it is also important to study the reproducibility of resulting layer thickness measurements, as layer thickness is a commonly used clinical parameter. In this work, twenty eight (14 x 2) repeated macular OCT volumes were acquired from the right eyes of 14 normal subjects using two Zeiss-Cirrus SD-OCT scanners. After segmentation of 10 intraretinal layers and rigid registration of layer thickness maps from the repeated OCT scans, the thickness difference of each layer was calculated. The overall mean global and regional thickness differences of 10 intraretinal layers were 0.46 +/- 0.25 μm (1.70 +/- 0.72 %) and 1.16 +/- 0.84 μm (4.03 +/- 2.05 %), respectively. No specific local region showed a consistent thickness difference across the layers.

  12. Auto-elimination of fiber optical path-length drift in a frequency scanning interferometer for absolute distance measurements

    NASA Astrophysics Data System (ADS)

    Tao, Long; Liu, Zhigang; Zhang, Weibo

    2015-09-01

    Because of its compact size and portability, optical fiber has been wildly used as optical paths in frequency-scanning interferometers for high-precision absolute distance measurements. However, since the fiber is sensitive to ambient temperature, its length and refractive index change with temperature, resulting in an optical path length drift that influences the repeatability of measurements. To improve the thermal stability of the measurement system, a novel frequency-scanning interferometer composed of two Michelson-type interferometers sharing a common fiber optical path is proposed. One interferometer defined as origin interferometer is used to monitor the drift of the measurement origin due to the optical path length drift of the optical fiber under on-site environment. The other interferometer defined as measurement interferometer is used to measure the distance to the target. Because the optical path length drift of the fiber appears in both interferometers, its influence can be eliminated by subtracting the optical path difference of the origin interferometer from the optical path difference of the measurement interferometer. A prototype interferometer was developed in our research, and experimental results demonstrate its robustness and stability. Under on-site environment, an accuracy about 4 μm was achieved for a distance of about 1 m.

  13. Resolving Differences in Absolute Irradiance Measurements Between the SOHO/CELIAS/SEM and the SDO/EVE

    NASA Astrophysics Data System (ADS)

    Wieman, S. R.; Didkovsky, L. V.; Judge, D. L.

    2014-08-01

    The Solar EUV Monitor (SEM) onboard SOHO has measured absolute extreme ultraviolet (EUV) and soft X-ray solar irradiance nearly continuously since January 1996. The EUV Variability Experiment (EVE) on SDO, in operation since April of 2010, measures solar irradiance in a wide spectral range that encompasses the band passes (26 - 34 nm and 0.1 - 50 nm) measured by SOHO/SEM. However, throughout the mission overlap, irradiance values from these two instruments have differed by more than the combined stated uncertainties of the measurements. In an effort to identify the sources of these differences and eliminate them, we investigate in this work the effect of reprocessing the SEM data using a more accurate SEM response function (obtained from synchrotron measurements with a SEM sounding-rocket clone instrument taken after SOHO was already in orbit) and time-dependent, measured solar spectral distributions - i.e., solar reference spectra that were unavailable prior to the launch of the SDO. We find that recalculating the SEM data with these improved parameters reduces mean differences with the EVE measurements from about 20 % to less than 5 % in the 26 - 34 nm band, and from about 35 % to about 15 % for irradiances in the 0.1 - 7 nm band extracted from the SEM 0.1 - 50 nm channel.

  14. Resolving Differences in Absolute Irradiance Measurements Between the SOHO/CELIAS/SEM and the SDO/EVE.

    PubMed

    Wieman, S R; Didkovsky, L V; Judge, D L

    The Solar EUV Monitor (SEM) onboard SOHO has measured absolute extreme ultraviolet (EUV) and soft X-ray solar irradiance nearly continuously since January 1996. The EUV Variability Experiment (EVE) on SDO, in operation since April of 2010, measures solar irradiance in a wide spectral range that encompasses the band passes (26 - 34 nm and 0.1 - 50 nm) measured by SOHO/SEM. However, throughout the mission overlap, irradiance values from these two instruments have differed by more than the combined stated uncertainties of the measurements. In an effort to identify the sources of these differences and eliminate them, we investigate in this work the effect of reprocessing the SEM data using a more accurate SEM response function (obtained from synchrotron measurements with a SEM sounding-rocket clone instrument taken after SOHO was already in orbit) and time-dependent, measured solar spectral distributions - i.e., solar reference spectra that were unavailable prior to the launch of the SDO. We find that recalculating the SEM data with these improved parameters reduces mean differences with the EVE measurements from about 20 % to less than 5 % in the 26 - 34 nm band, and from about 35 % to about 15 % for irradiances in the 0.1 - 7 nm band extracted from the SEM 0.1 - 50 nm channel.

  15. A technique for measuring absolute toe pressures: evaluation of pressure-sensitive film techniques.

    PubMed

    Tuckman, A S; Werner, F W; Fortino, M D; Spadaro, J A

    1992-05-01

    Although a number of pathologies of the forefoot in ballet dancers on pointe have been described, pressures and deforming forces have not been adequately measured. To evaluate the possible use of pressure-sensitive film (PSF) in measuring the pressures on the external soft tissues in such a confined space as the dancer's toe shoe, it was tested and calibrated with 20 cadaver toes. Each cadaver toe was internally stabilized and loaded longitudinally against PSF on a flat surface. The resultant films were analyzed with a video imaging system and the pressures and total forces were determined. Results showed that the linearity of the PSF to pressure had a regression value of 0.98. By using two sensitivity ranges of films, the total force measured by the PSF was found to be within 10% of the known applied force on each toe. The PSF, therefore, may very well be a useful and accurate method of measuring external soft tissue pressures on the forefoot.

  16. A new measurement method of coatings thickness based on lock-in thermography

    NASA Astrophysics Data System (ADS)

    Zhang, Jin-Yu; Meng, Xiang-bin; Ma, Yong-chao

    2016-05-01

    Coatings have been widely used in modern industry and it plays an important role. Coatings thickness is directly related to the performance of the functional coatings, therefore, rapid and accurate coatings thickness inspection has great significance. Existing coatings thickness measurement method is difficult to achieve fast and accurate on-site non-destructive coatings inspection due to cost, accuracy, destruction during inspection and other reasons. This paper starts from the introduction of the principle of lock-in thermography, and then performs an in-depth study on the application of lock-in thermography in coatings inspection through numerical modeling and analysis. The numerical analysis helps explore the relationship between coatings thickness and phase, and the relationship lays the foundation for accurate calculation of coatings thickness. The author sets up a lock-in thermography inspection system and uses thermal barrier coatings specimens to conduct an experiment. The specimen coatings thickness is measured and calibrated to verify the quantitative inspection. Experiment results show that the lock-in thermography method can perform fast coatings inspection and the inspection accuracy is about 95%. Therefore, the method can meet the field testing requirements for engineering projects.

  17. Multimodal optical measurement in vitro of surface deformations and wall thickness of the pressurized aortic arch.

    PubMed

    Genovese, Katia; Humphrey, Jay D

    2015-04-01

    Computational modeling of arterial mechanics continues to progress, even to the point of allowing the study of complex regions such as the aortic arch. Nevertheless, most prior studies assign homogeneous and isotropic material properties and constant wall thickness even when implementing patient-specific luminal geometries obtained from medical imaging. These assumptions are not due to computational limitations, but rather to the lack of spatially dense sets of experimental data that describe regional variations in mechanical properties and wall thickness in such complex arterial regions. In this work, we addressed technical challenges associated with in vitro measurement of overall geometry, full-field surface deformations, and regional wall thickness of the porcine aortic arch in its native anatomical configuration. Specifically, we combined two digital image correlation-based approaches, standard and panoramic, to track surface geometry and finite deformations during pressurization, with a 360-deg fringe projection system to contour the outer and inner geometry. The latter provided, for the first time, information on heterogeneous distributions of wall thickness of the arch and associated branches in the unloaded state. Results showed that mechanical responses vary significantly with orientation and location (e.g., less extensible in the circumferential direction and with increasing distance from the heart) and that the arch exhibits a nearly linear increase in pressure-induced strain up to 40%, consistent with other findings on proximal porcine aortas. Thickness measurements revealed strong regional differences, thus emphasizing the need to include nonuniform thicknesses in theoretical and computational studies of complex arterial geometries.

  18. Improved determination of seafloor absolute magnetization from uneven, near-seafloor magnetic measurements and high-resolution bathymetry

    NASA Astrophysics Data System (ADS)

    Szitkar, F.; Dyment, J.; Choi, Y.; Fouquet, Y.

    2012-12-01

    Vector magnetometers installed on deep-sea submersibles offer a unique opportunity to achieve high resolution magnetic investigations at the scale of hundred to thousand meters. Once corrected for the vehicle induced and remanent magnetization, the measurements mostly reflect variations of the topography and the submersible path - i.e. the distance between the sources and the observation points. The interesting parameter, however, is the seafloor magnetization that can be interpreted in terms of geological processes. Here we present methods to compute absolute magnetization of the seafloor by taking advantage of the uneven track of the submersible. In these methods, synthetic anomalies are computed for a unit magnetization assuming the geometry of the experiment, i.e. the source and the submersible path. The absolute magnetization is determined by a comparison between the observed anomalies and the synthetic ones along sliding windows. The coherency between the two signals gives an estimation of the quality of the determination, and the phase provides information on the magnetic polarity, and therefore the age of volcanic features. Such a method has been developed by Honsho et al. (JGR, 2009) using deep-sea submersible data only, i.e. magnetic anomaly, depth and altitude of the submersible. The synthetic anomalies are computed using 2D forward modeling, i.e. assuming the structures to be infinite in the direction perpendicular to the submersible path. The method has been applied with success to linear profiles crossing elongated structures such as mid-ocean ridges, but may fail for structures departing from the 2D assumption. The adaptation of improving multibeam systems to autonomous underwater vehicles (AUVs) has opened the way to the collection of very high resolution bathymetric data (around 2m between each measurement). This development has triggered a new strategy to explore the seafloor using manned submersibles: an AUV is operated during night time to

  19. Thin layer thickness measurements by zero group velocity Lamb mode resonances.

    PubMed

    Cès, Maximin; Clorennec, Dominique; Royer, Daniel; Prada, Claire

    2011-11-01

    Local and non-contact measurements of the thickness of thin layers deposited on a thick plate have been performed by using zero group velocity (ZGV) Lamb modes. It was shown that the shift of the resonance frequency is proportional to the mass loading through a factor which depends on the mechanical properties of the layer and of the substrate. In the experiments, ZGV Lamb modes were generated by a Nd:YAG pulsed laser and the displacement normal to the plate surface was measured by an optical interferometer. Measurements performed at the same point that the generation on the non-coated face of the plate demonstrated that thin gold layers of a few hundred nanometers were detected through a 1.5-mm thick Duralumin plate. The shift of the resonance frequency (1.9 MHz) of the fundamental ZGV mode is proportional to the layer thickness: typically 10 kHz per μm. Taking into account the influence of the temperature, a 240-nm gold layer was measured with a ±4% uncertainty. This thickness has been verified on the coated face with an optical profiling system.

  20. On-Line Measurement of Lubricant Film Thickness Using Ultrasonic Reflection Coefficients

    SciTech Connect

    Drinkwater, B.W.; Dwyer-Joyce, R.S.; Harper, P.

    2004-02-26

    The ultrasonic reflectivity of a lubricant layer between two solid bodies depends on the ultrasonic frequency, the acoustic properties of the liquid and solid, and the layer thickness. In this paper, ultrasonic reflectivity measurements are used as a method for determining the thickness of lubricating films in bearing systems. An ultrasonic transducer is positioned on the outside of a bearing shell such that the wave is focused on the lubricant film layer. For a particular lubricant film the reflected pulse is processed to give a reflection coefficient spectrum. The lubricant film thickness is then obtained from either the layer stiffness or the resonant frequency. The method has been validated using static fluid wedges and the elastohydrodynamic film formed between a ball sliding on a flat. Film thickness values in the range 50-500 nm were recorded which agreed well with theoretical film formation predictions.

  1. Direct determination of the thickness of stratospheric layers from single-channel satellite radiance measurements.

    NASA Technical Reports Server (NTRS)

    Quiroz, R. S.; Gelman, M. E.

    1972-01-01

    The direct use of measured radiances for determining the thickness of stratospheric layers is investigated. Layers based at 100-10 mb, with upper boundaries at 10-0.5 mb, are investigated using a carefully selected family of stratospheric temperature profiles and computed radiances. On the basis of physical reasoning, a high correlation of thickness with radiance is anticipated for deep layers, such as the 100- to 2-mb layer (from about 15 to 43 km), that emit a substantial part of the infrared energy reaching a satellite radiometer in a particular channel. Empirical regression curves relating thickness and radiance are developed and are compared with blackbody curves obtained by substituting the blackbody temperature in the hydrostatic equation. Maximum thickness-radiance correlation is found, for each infrared channel, for the layer having the best agreement of empirical and blackbody curves.

  2. Measurement of the absolute branching fraction of Ds+ --> tau+ nutau decay.

    PubMed

    Ecklund, K M; Love, W; Savinov, V; Lopez, A; Mendez, H; Ramirez, J; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Rademacker, J; Asner, D M; Edwards, K W; Naik, P; Reed, J; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Libby, J; Powell, A; Wilkinson, G

    2008-04-25

    Using a sample of tagged D(s)(+) decays collected near the D(s)(*+/-)D(s)(-/+) peak production energy in e(+)e(-) collisions with the CLEO-c detector, we study the leptonic decay D(s)(+)-->tau(+)nu(tau) via the decay channel tau(+)-->e(+)nu(e)nu(tau). We measure B(D(s)(+)-->tau(+)nu(tau))=(6.17+/-0.71+/-0.34)%, where the first error is statistical and the second systematic. Combining this result with our measurements of D(s)(+)-->mu(+)nu(mu) and D(s)(+)-->tau(+)nu(tau) (via tau(+)-->pi(+)nu(tau)), we determine f(D(s))=(274+/-10+/-5) MeV.

  3. Thin film thickness measurement of whole field based on spatial carrier frequency interferometry

    NASA Astrophysics Data System (ADS)

    Su, Junhong; Yang, Lihong; Ge, Jinman

    2009-12-01

    The kernel of modern interferometry is to the obtain necessary surface shape and parameter by processing interferogram with a reasonable algorithm. On the basis of the study the basic principle of interferometry by using 2-D FFT arithmetic, a new method to measure the thin film thickness is proposed based on the FFT algorithm. A test sample is placed into the light path in Twyman-Green interferometer, the interference fringes were generated by the reference beam with the tested beam reflected respectively from the film surface and the substrate surface. The interferogram is collected by the image acquisition system. The algorithm processing software is prepared to realize identification of the films edge, regional extension, filtering, unwrapping the wrapped phase etc, the film thickness distribution in whole field can be obtained to realize the thickness measurement of thin film samples automatically. The results indicate that the new method has the advantages of high precision, whole test and non-contact measurement.

  4. Thin film thickness measurement of whole field based on spatial carrier frequency interferometry

    NASA Astrophysics Data System (ADS)

    Su, Junhong; Yang, Lihong; Ge, Jinman

    2010-03-01

    The kernel of modern interferometry is to the obtain necessary surface shape and parameter by processing interferogram with a reasonable algorithm. On the basis of the study the basic principle of interferometry by using 2-D FFT arithmetic, a new method to measure the thin film thickness is proposed based on the FFT algorithm. A test sample is placed into the light path in Twyman-Green interferometer, the interference fringes were generated by the reference beam with the tested beam reflected respectively from the film surface and the substrate surface. The interferogram is collected by the image acquisition system. The algorithm processing software is prepared to realize identification of the films edge, regional extension, filtering, unwrapping the wrapped phase etc, the film thickness distribution in whole field can be obtained to realize the thickness measurement of thin film samples automatically. The results indicate that the new method has the advantages of high precision, whole test and non-contact measurement.

  5. Cavity-enhanced measurements for determining dielectric-membrane thickness and complex index of refraction.

    PubMed

    Stambaugh, Corey; Durand, Mathieu; Kemiktarak, Utku; Lawall, John

    2014-08-01

    The material properties of silicon nitride (SiN) play an important role in the performance of SiN membranes used in optomechanical applications. An optimum design of a subwavelength high-contrast grating requires accurate knowledge of the membrane thickness and index of refraction, and its performance is ultimately limited by material absorption. Here we describe a cavity-enhanced method to measure the thickness and complex index of refraction of dielectric membranes with small, but nonzero, absorption coefficients. By determining Brewster's angle and an angle at which reflection is minimized by means of destructive interference, both the real part of the index of refraction and the sample thickness can be measured. A comparison of the losses in the empty cavity and the cavity containing the dielectric sample provides a measurement of the absorption.

  6. Using NDT for thickness measurement of shotcrete rock support systems in underground mines

    NASA Astrophysics Data System (ADS)

    Guevremont, P.; Hassani, F. P.; Momayez, M.

    2000-05-01

    Shotcrete is quickly becoming the economical material of choice for rock support systems in underground mines throughout Canada. Although shotcrete technology has gained acceptance in the mining industry, there are some problems which have emerged with respect to quality assessment and thickness measurement of the liner. This paper presents recent tests performed with a miniature seismic reflection device developed primarily for thickness measurement of this heterogeneous liner. Work was performed on site in an underground mine in Ontario, Canada. This paper also presents the results from laboratory tests performed on fiber reinforced an non reinforced shotcrete panels which were used to asses the P-wave velocity in both materials. The results of these tests were used in a second on site investigation. The NDT thickness measurements showed good agreement with the results obtained by mine personnel with conventional methods.

  7. Local Variability of Macular Thickness Measurements With SD-OCT and Influencing Factors

    PubMed Central

    Miraftabi, Arezoo; Amini, Navid; Gornbein, Jeff; Henry, Sharon; Romero, Pablo; Coleman, Anne L.; Caprioli, Joseph; Nouri-Mahdavi, Kouros

    2016-01-01

    Purpose To compare the intrasession variability of spectral-domain optical coherence tomography (SD-OCT)-derived local macular thickness measures and explore influencing factors. Methods One hundred two glaucomatous eyes (102 patients) and 21 healthy eyes (21 subjects) with three good quality macular images during the same session were enrolled. Thickness measurements were calculated for 3° superpixels for the inner plexiform (IPL), ganglion cell (GCL), or retinal nerve fiber layers (mRNFL), GC/IPL, ganglion cell complex, and full macular thickness. Spatial distribution and magnitude of measurement errors (ME; differences between the 3 individual superpixel values and their mean) and association between MEs and thickness, age, axial length, and image quality were explored. Results MEs had a normal distribution with mostly random noise along with a small fraction of outliers (1.2%–6.6%; highest variability in mRNFL and on the nasal border) based on M-estimation. Boundaries of 95% prediction intervals for variability reached a maximum of 3 μm for all layers and diagnostic groups after exclusion of outliers. Correlation between proportion of outliers and thickness measures varied among various parameters. Age, axial length, or image quality did not influence MEs (P > 0.05 for both groups). Conclusions Local variability of macular SD-OCT measurements is low and uniform across the macula. The relationship between superpixel thickness and outlier proportion varied as a function of the parameter of interest. Translational Relevance Given the low and uniform variability within and across eyes, definition of an individualized ‘variability space' seems unnecessary. The variability measurements from this study could be used for designing algorithms for detection of glaucoma progression. PMID:27486555

  8. Solar rotation measurements at Mount Wilson. II - Systematic instrumental effects and the absolute rotation rate

    NASA Technical Reports Server (NTRS)

    Labonte, B. J.; Howard, R.

    1981-01-01

    Possible sources of systematic error in solar Doppler rotational velocities are examined. Scattered light is shown to affect the Mount Wilson solar rotation results, but this effect is not enough to bring the spectroscopic results in coincidence with the sunspot rotation. Interference fringes at the spectrograph focus at Mount Wilson have in two intervals affected the rotation results. It has been possible to correlate this error with temperature and thus correct for it. A misalignment between the entrance and exit slits is a possible source of error, but for the Mount Wilson slit configuration, the amplitude of this effect is negligibly small. Rapid scanning of the solar image also produces no measurable effect.

  9. Absolute np and pp cross section determinations aimed at improving the standard for cross section measurements

    SciTech Connect

    Laptev, Alexander B; Haight, Robert C; Tovesson, Fredrik; Arndt, Richard A; Briscoe, William J; Paris, Mark W; Strakovsky, Igor I; Workman, Ron L

    2010-01-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses (PW As) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-V11.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  10. Absolute np and pp Cross Section Determinations Aimed At Improving The Standard For Cross Section Measurements

    SciTech Connect

    Laptev, A. B.; Haight, R. C.; Tovesson, F.; Arndt, R. A.; Briscoe, W. J.; Paris, M. W.; Strakovsky, I. I.; Workman, R. L.

    2011-06-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1 GeV are determined based on partial-wave analyses (PWAs) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-VII.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  11. Regularity of absolutely continuous invariant measures for piecewise expanding unimodal maps

    NASA Astrophysics Data System (ADS)

    Contreras, Fabián; Dolgopyat, Dmitry

    2016-09-01

    Let f:[0,1]\\to [0,1] be a piecewise expanding unimodal map of class C  k+1, with k≥slant 1 , and μ =ρ \\text{d}x the (unique) SRB measure associated to it. We study the regularity of ρ. In particular, points N where ρ is not differentiable has zero Hausdorff dimension, but is uncountable if the critical orbit of f is dense. This improves on a work of Szewc (1984). We also obtain results about higher orders of differentiability of ρ in the sense of Whitney.

  12. Simultaneous thickness and group index measurement with a single arm low-coherence interferometer.

    PubMed

    Zilio, S C

    2014-11-03

    We present a single arm low-coherence interferometer to directly measure the physical thickness and group refractive index of optically transparent samples having flat and parallel surfaces. The optical arrangement, resembling a common-path interferometer, is more compact and stable than the usual dual-arm low-coherence interferometer. It has been used to measure samples of Herasil 102 fused silica, Schott B270 Superwhite crown glass and borosilicate cover glass. The results obtained indicate uncertainties in the third decimal place for index values and thicknesses accurate to within 2 μm.

  13. Simultaneous measurement of group refractive index and thickness of optical samples using optical coherence tomography.

    PubMed

    Cheng, Hsu-Chih; Liu, Yi-Cheng

    2010-02-10

    Optical coherence tomography (OCT), based on a Michelson interferometer and utilizing low coherence light as the optical source, is a novel technique for the noninvasive imaging of optical scattering media. A simple OCT scheme based on a 3 x 3 fiber coupler is presented for the simultaneous measurement of the refractive index and thickness of optical samples. The proposed system enables the refractive index and thickness to be determined without any prior knowledge of the sample parameters and is characterized by a simple and compact configuration, a straightforward measurement procedure, and a low cost. The feasibility of the proposed approach is demonstrated experimentally using BK7 and B270 optical glass samples.

  14. Thin-film thickness profile and its refractive index measurements by dispersive white-light interferometry.

    PubMed

    Ghim, Young-Sik; Kim, Seung-Woo

    2006-11-27

    As an extension of the authors' previous report of Ref 1, we describe an improved version of dispersive white-light interferometry that enables us to measure the tomographical thickness profile of a thin-film layer through Fourier-transform analysis of spectrally-resolved interference signals. The group refractive index can also be determined without prior knowledge of the geometrical thickness of the film layer. Owing to fast measurement speed with no need of mechanical depth scanning, the proposed method is well suited for in-line 3-D inspection of dielectric thin film layers particularly for the semiconductor and flat-panel display industry.

  15. Development of an Airborne Sea Ice Thickness Measurement System and Field Test Results

    DTIC Science & Technology

    1989-12-01

    Kovacs and J . Scott Holladay PJTIS CRA&I DTIC TAB Unannronced JustiCaton By Distribution I AvaIabilit Cordes AvjII d-dlc, Dist Prepared for U.S...Development of an Airborne Sea Ice Thickness Measurement System and Field Test Results 12. PERSONAL AUTHOR(S) Kovacs, Austin and Holladay, J . Scott 13a...Thickness Measurement System and Field Test Results AUSTIN KOVACS AND J . SCOTT HOLLADAY INTRODUCTION was determined to be desirable. The goals of the 1986-87

  16. Comparison of Central Corneal Thickness Measurements by Pentacam and Ultrasound Pachymetry in Normal Myopic Patients

    PubMed Central

    Emerah, Sherif; ELZakzouk, Ehab; Farag, Mohamed

    2016-01-01

    Introduction Precise measurement of corneal thickness is of crucial importance in corneal refractive procedures. The aim of this work is to compare the central corneal thickness measurements using Scheimpflug imaging (Pentacam) and contact US pachymetry in normal myopic patients. Methods This retrospective cohort study was conducted on in 144 eyes of 72 normal myopic patients during 6 months. The study location was the Research Institute of Ophthalmology (Giza, Egypt), and Magrabi Eye Hospital (Dubai, United Arab Emirates). Central corneal thickness was measured with the two devices. Data were analyzed by descriptive statistics, independent-samples t-test, paired-samples t-test, Mann-Whitney U test and Pearson-Product Moment Correlation Coefficient. Results The mean age was 25.3±5.6 years (range 18 to 38 years). The median age for our patients is 24 years. The average measurements of CCT were 526.8±35.3 and 529.1±37.9 for the Pentacam pachymetry and US pachymetry values, respectively. Mean difference between both measurements was 2.3±2.6μm which is statistically insignificant (p=0.08). Bland Altman Plot shows border line agreement of the two methods US pachymetry and Pentacam in detection of central corneal thickness. Conclusion The results of this study showed no significant differences in CCT readings between the measurements obtained by Pentacam and US pachymetry in normal myopic patients. PMID:28163862

  17. Measurement of the Absolute Branching Fractions of$B^\\pm \\to K^\\pm X_{c\\bar c}$

    SciTech Connect

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Pappagallo, M.; Pompili, A.; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Karlsruhe U., EKP /Imperial Coll., London /Iowa U. /Iowa State U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /INFN, Padua /Paris U., VI-VII /Pennsylvania U. /Perugia U. /INFN, Perugia /Pisa U. /INFN, Pisa /Prairie View A-M /Princeton U. /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Stony Brook /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Vanderbilt U. /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U. /Basilicata U., Potenza

    2005-11-02

    We study the two-body decays of B{sup {+-}} mesons to K{sup {+-}} and a charmonium state, X{sub c{bar c}}, in a sample of 210.5 fb{sup -1} of data from the BABAR experiment. We perform measurements of absolute branching fractions {Beta}(B{sup {+-}} {yields} K{sup {+-}} X{sub c{bar c}}) using a missing mass technique, and report several new or improved results. In particular, the upper limit {Beta}(B{sup {+-}} {yields} K{sup {+-}}(3872)) < 3.2 x 10{sup -4} at 90% CL and the inferred lower limit {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) > 4.2% will help in understanding the nature of the recently discovered X(3872).

  18. Chest wall thickness measurements of the LLNL and JAERI torso phantoms for germanium detector counting

    SciTech Connect

    Kramer, G.H.; Hauck, B.M.

    1997-11-01

    The Lawrence Livermore National Laboratory and Japanese Atomic Energy Research Institute torso phantoms were developed to calibrate lung counting systems that are used to estimate plutonium and other radionuclides deposited in the lung. Originally, low energy photon counting systems consisted of phoswich detectors. The average chest wall thicknesses and individual measurement points of the Lawrence Livermore National Laboratory phantom and its overlay plates in the regions covered by these detectors were provided by the manufacturer. Germanium detectors are of a different size and are placed in different locations on the phantom so that the manufacturer`s data are no longer applicable for the locations of the germanium detectors on the phantom. The Human Monitoring Laboratory has re-evaluated the chest wall thickness of both the Lawrence Livermore National Laboratory and Japanese Atomic Energy Research Institute phantoms and their overlay plates for its germanium lung counting system. The measurements were made in the upper right, lower right, upper left, and lower left positions on the phantom`s torso plate above the lungs. The effective chest wall thicknesses (17 keV) for the Lawrence Livermore National Laboratory torso plate are 1.46 cm, 1.43 cm, 1.66 cm, 1.48 cm, respectively. The manufacturer`s quoted average effective chest wall thickness for a pair of phoswich detectors is 1.63 cm. The measured effective chest wall thicknesses (17 keV) for the JAERI`s torso plate are 1.76 cm, 2.15 cm, 1.79 cm, 2.15 cm, respectively. The manufacturer`s quoted average chest wall thickness for an unspecified region of the chest is 1.50 cm. This paper presents effective chest wall thickness data for the phantoms with and without their overlay plates at 17 keV, 60 keV, 200 keV and 1,500 keV. 13 refs., 2 figs., 4 tabs.

  19. Potential for airborne offbeam lidar measurements of snow and sea ice thickness

    NASA Astrophysics Data System (ADS)

    VáRnai, TamáS.; Cahalan, Robert F.

    2007-12-01

    This article discusses the capabilities and limitations of a new approach to airborne measurements of snow and sea ice thickness. Such measurements can help better understand snow and sea ice processes and can also contribute to the validation of satellite measurements. The approach discussed here determines physical snow and sea ice thickness by observing the horizontal spread of lidar pulses: The bright halo observed around an illuminated spot extends farther out in thicker layers because photons can travel longer without escaping through the bottom. Since earlier studies suggested the possibility of such sea ice retrievals, this article presents a theoretical analysis of additional uncertainties that arise in airborne observations of snow and sea ice. Snow and sea ice retrievals pose somewhat different challenges because while sea ice is usually much thicker, snow contains a much higher concentration of scatterers. As a result, sea ice halos are larger, but snow halos are brighter. The results indicate that airborne sea ice retrievals are possible at night and that snow retrievals are possible during both night and day. For snow thicknesses less than about 50 cm, observational issues, such as calibration uncertainty, can cause retrieval uncertainties on the order of 10% in 1-km-resolution retrievals. For moderate snow and sea ice thicknesses (<30 cm and 3 m, respectively), these issues cause similar (˜10%) uncertainties in sea ice thickness retrievals as well. These results indicate that offbeam lidars have the potential to become an important component of future snow and sea ice observing systems.

  20. Diode laser-based standoff absorption measurement of water film thickness in retro-reflection

    NASA Astrophysics Data System (ADS)

    Pan, R.; Brocksieper, C.; Jeffries, J. B.; Dreier, T.; Schulz, C.

    2016-09-01

    A dual-wavelength diode laser-based absorption sensor for standoff point measurements of water film thickness on an opaque surface is presented. The sensor consists of a diode laser source, a foil as backscattering target, and off-axis paraboloids for collecting the fraction of the laser radiation transmitted through the liquid layer via retro-reflection. Laser wavelengths in the near infrared at 1412 and 1353 nm are used where the temperature dependence of the liquid water absorption cross section is known. The lasers are fiber coupled and the detection of the retro-reflected light was accomplished through a multimode fiber and a single photodiode using time-division multiplexing. The water film thickness at a given temperature was determined from measured transmittance ratios at the two laser wavelengths. The sensor concept was first validated with measurement using a temperature-controlled calibration cell providing liquid layers of variable and known thickness between 100 and 1000 µm. Subsequently, the sensor was demonstrated successfully during recording the time-varying thickness of evaporating water films at fixed temperatures. The film thickness was recorded as a function of time at three temperatures down to 50 µm.

  1. Monitoring water storage changes using absolute gravity measurements, neutron probes and piezometer data in West Africa: advances in specific yield and recharge estimation

    NASA Astrophysics Data System (ADS)

    Hector, B.; Séguis, L.; Descloîtres, M.; Hinderer, J.; Wubda, M.; Luck, B.; Le Moigne, N.

    2012-04-01

    Advances in water storage monitoring are crucial to characterize the spatial variability of hydrological processes. Classical water storage investigation methods often involve point measurements (piezometers, neutron probes, humidity sensors…), which may be irrelevant in heterogeneous mediums. Over the past few years, there has been an increasing interest in the use of gravimeters for hydrological studies. Water mass redistribution leads to variations in the Earth's gravity field which can be measured by gravimetry. In the framework of the GHYRAF (Gravity and Hydrology in Africa) project, 3 years of repeated absolute gravity measurements using FG5#206 from Micro-g Solutions Inc. have been undertaken at Nalohou, a Sudanian site in northern Benin. Hydrological monitoring is carried out within the long-term observing system AMMA-Catch (an observatory of RBV, the French critical zone exploration network). Seasonal gravity variations in link with the hydrological cycle can reach 11 µgal at this site, equivalent to a 26cm thick infinite layer of water. The vadose zone and a shallow unconfined aquifer in weathered metamorphic rocks are responsible for most of the water storage variations. For the first time in the climatic context of the West African monsoon, gravity data are compared to the time evolution of the water storages deduced from neutron probes and water-table variations. The approach is two-fold: first, total storage variations are estimated from neutron probe-derived moisture through the whole vertical profile (surface to groundwater) monitored at the gravimetric site and uniformly extended according to the topography. Results show a very good fit with gravity data, enlightening the fact that absolute gravimeters are sensitive to total water storage variations from the soil surface to the aquifer. The second approach introduces a spatial variability: it was undertaken to check a structural model for specific yield of the aquifer, based on magnetic

  2. Absolute branching fraction measurements for D+ and D0 inclusive semileptonic decays.

    PubMed

    Adam, N E; Alexander, J P; Berkelman, K; Cassel, D G; Duboscq, J E; Ecklund, K M; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Meyer, T O; Onyisi, P U E; Patterson, J R; Peterson, D; Pivarski, J; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Weinberger, M; Athar, S B; Patel, R; Potlia, V; Stoeck, H; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; White, E J; Wiss, J; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Smith, A; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Ernst, J; Severini, H; Dytman, S A; Love, W; Savinov, V; Aquines, O; Li, Z; Lopez, A; Mehrabyan, S; Mendez, H; Ramirez, J; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Artuso, M; Blusk, S; Butt, J; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, K; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Briere, R A; Brock, I; Chen, J; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L

    2006-12-22

    We present measurements of the inclusive branching fractions for the decays D+-->Xe+ nu(e) and D0-->Xe+ nu(e), using 281 pb(-1) of data collected on the psi(3770) resonance with the CLEO-c detector. We find B(D0-->Xe+ nu(e)) = (6.46+/-0.17+/-0.13)% and B(D+-->Xe+ nu(e)) = (16.13+/-0.20+/-0.33)%. Using the known D meson lifetimes, we obtain the ratio Gamma(D+)sl/Gamma(D0)sl = 0.985+/-0.028+/-0.015, confirming isospin invariance at the level of 3%. The positron momentum spectra from D+ and D0 have consistent shapes.

  3. Measurement of the absolute differential cross section of proton–proton elastic scattering at small angles

    DOE PAGES

    Mchedlishvili, D.; Chiladze, D.; Dymov, S.; ...

    2016-02-03

    The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis.more » Furthermore, after extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.« less

  4. Measurement of the absolute differential cross section of proton–proton elastic scattering at small angles

    SciTech Connect

    Mchedlishvili, D.; Chiladze, D.; Dymov, S.; Bagdasarian, Z.; Barsov, S.; Gebel, R.; Gou, B.; Hartmann, M.; Kacharava, A.; Keshelashvili, I.; Khoukaz, A.; Kulessa, P.; Kulikov, A.; Lehrach, A.; Lomidze, N.; Lorentz, B.; Maier, R.; Macharashvili, G.; Merzliakov, S.; Mikirtychyants, S.; Nioradze, M.; Ohm, H.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Schroer, D.; Shmakova, V.; Stassen, R.; Stein, H. J.; Stockhorst, H.; Strakovsky, I. I.; Stroher, H.; Tabidze, M.; Taschner, A.; Trusov, S.; Tsirkov, D.; Uzikov, Yu.; Valdau, Yu.; Wilkin, C.; Workman, R. L.; Wustner, P.

    2016-02-03

    The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis. Furthermore, after extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.

  5. Procoagulant and platelet-derived microvesicle absolute counts determined by flow cytometry correlates with a measurement of their functional capacity

    PubMed Central

    Ayers, Lisa; Harrison, Paul; Kohler, Malcolm; Ferry, Berne

    2014-01-01

    Background Flow cytometry is the most commonly used technology to measure microvesicles (MVs). Despite reported limitations of this technique, MV levels obtained using conventional flow cytometry have yielded many clinically relevant findings, such as associations with disease severity and ability to predict clinical outcomes. This study aims to determine if MV enumeration by flow cytometry correlates with a measurement of their functional capacity, as this may explain how flow cytometry generates clinically relevant results. Methods One hundred samples from healthy individuals and patients with obstructive sleep apnoea were analysed by conventional flow cytometry (FACSCalibur) and by three functional MV assays: Zymuphen MP-activity in which data were given as phosphatidylserine equivalent, STA® Phospholipid Procoag Assay expressed as clotting time and Endogenous Thrombin Potential (ETP) reflecting in vitro thrombin generation. Correlations were determined by Spearman correlation. Results Absolute counts of lactadherin+ procoagulant MVs generated by flow cytometry weakly correlated with the results obtained from the Zymuphen MP-activity (r=0.5370, p<0.0001); correlated with ETP (r=0.7444, p<0.0001); negatively correlated with STA® Phospholipid Procoag Assay clotting time (−0.7872, p<0.0001), reflecting a positive correlation between clotting activity and flow cytometry. Levels of Annexin V+ procoagulant and platelet-derived MVs were also associated with functional assays. Absolute counts of MVs derived from other cell types were not correlated with the functional results. Conclusions Quantitative results of procoagulant and platelet-derived MVs from conventional flow cytometry are associated with the functional capability of the MVs, as defined by three functional MV assays. Flow cytometry is a valuable technique for the quantification of MVs from different cellular origins; however, a combination of several analytical techniques may give the most comprehensive

  6. Static measurement of the thickness of the ablative coating of the solid rocket boosters

    NASA Technical Reports Server (NTRS)

    Harrison, Harry C.

    1996-01-01

    The Solid Rocket Boosters (SRB's) used to launch the Space Shuttle are coated with a layer of ablative material to prevent thermal damage when they reenter the earth's atmosphere. The coating consists of a mixture of cork, glass, and resin. A new coating (Marshall Convergent Coating, MCC-2) was recently developed that is environmentally complaint. The coating must meet certain minimum thickness standards in order to protect the SRB. The coating is applied by a robot controlled nozzle that moves from the bottom to top, as the rocket part rotates on a table. Several coats are applied, building up to the desired thickness. Inspectors do a limited amount of destructive 'wet' testing. This involves an inspector inserting a rod in the wet coating and removing the rod. This results in a hole that, of course, must be patched later. The material is cured and the thickness is measured. There is no real-time feedback as the coating is being applied. Although this might seem like the best way to control thickness, the problems with 'blowback' (reflected material covering the sensor) are formidable, and have not been solved. After the thermal coating is applied, a protective top coat is applied. The SRB part is then placed in a oven and baked to harden the surface. The operations personnel then measure the thickness of the layer using the Kaman 7200 Displacement Measuring System. The probe is placed on the surface. One person (the inspector) reads the instrument, while another(the technician) records the thickness. Measurements are taken at one foot intervals. After the measurements are taken, the number of low readings is tabulated. If more than 10 percent of the points fall below the minimum value, there is a design review, and the part may be stripped of coating, and a new coating is applied. There is no other analysis.

  7. The Relationship between OCT-measured Central Retinal Thickness and Visual Acuity in Diabetic Macular Edema

    PubMed Central

    2008-01-01

    Objective To compare optical coherence tomography (OCT)-measured retinal thickness and visual acuity in eyes with diabetic macular edema (DME) both before and after macular laser photocoagulation. Design Cross-sectional and longitudinal study. Participants 210 subjects (251 eyes) with DME enrolled in a randomized clinical trial of laser techniques. Methods Retinal thickness was measured with OCT and visual acuity was measured with the electronic-ETDRS procedure. Main Outcome Measures OCT-measured center point thickness and visual acuity Results The correlation coefficients for visual acuity versus OCT center point thickness were 0.52 at baseline and 0.49, 0.36, and 0.38 at 3.5, 8, and 12 months post-laser photocoagulation. The slope of the best fit line to the baseline data was approximately 4.4 letters (95% C.I.: 3.5, 5.3) better visual acuity for every 100 microns decrease in center point thickness at baseline with no important difference at follow-up visits. Approximately one-third of the variation in visual acuity could be predicted by a linear regression model that incorporated OCT center point thickness, age, hemoglobin A1C, and severity of fluorescein leakage in the center and inner subfields. The correlation between change in visual acuity and change in OCT center point thickening 3.5 months after laser treatment was 0.44 with no important difference at the other follow-up times. A subset of eyes showed paradoxical improvements in visual acuity with increased center point thickening (7–17% at the three time points) or paradoxical worsening of visual acuity with a decrease in center point thickening (18%–26% at the three time points). Conclusions There is modest correlation between OCT-measured center point thickness and visual acuity, and modest correlation of changes in retinal thickening and visual acuity following focal laser treatment for DME. However, a wide range of visual acuity may be observed for a given degree of retinal edema and paradoxical

  8. Measurement of absolute auditory thresholds in the common marmoset (Callithrix jacchus).

    PubMed

    Osmanski, Michael S; Wang, Xiaoqin

    2011-07-01

    The common marmoset is a small, arboreal, New World primate that has emerged as a promising non-human model system in auditory neuroscience. A complete understanding of the neuroethology of auditory processing in marmosets will include behavioral work examining how sounds are perceived by these animals. However, there have been few studies of the marmoset's hearing and perceptual abilities and the audiogram of this species has not been measured using modern psychophysical methods. The present experiment pairs psychophysics with an operant conditioning technique to examine perception of pure tone stimuli by marmosets using an active behavioral paradigm. Subjects were trained to lick at a feeding tube when they detected a sound. Correct responses provided access to a food reward. Pure tones of varying intensities were presented to subjects using the method of constant stimuli. Behavioral thresholds were calculated for each animal based on hit rate--threshold was defined by the tone intensity that the animal correctly identified 50% of the time. Results show that marmoset hearing is comparable to that of other New World monkeys, with a hearing range extending from about 125 Hz up to 36 kHz and a sensitivity peak around 7 kHz.

  9. Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Blancon, Jean-Christophe; Paillet, Matthieu; Tran, Huy Nam; Than, Xuan Tinh; Guebrou, Samuel Aberra; Ayari, Anthony; Miguel, Alfonso San; Phan, Ngoc-Minh; Zahab, Ahmed-Azmi; Sauvajol, Jean-Louis; Fatti, Natalia Del; Vallée, Fabrice

    2013-09-01

    The optical properties of single-wall carbon nanotubes are very promising for developing novel opto-electronic components and sensors with applications in many fields. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial. Here we determine using spatial modulation spectroscopy, over a broad optical spectral range, the spectrum and amplitude of the absorption cross-section of individual semiconducting single-wall carbon nanotubes. These quantitative measurements permit determination of the oscillator strength of the different excitonic resonances and their dependencies on the excitonic transition and type of semiconducting nanotube. A non-resonant background is also identified and its cross-section comparable to the ideal graphene optical absorbance. Furthermore, investigation of the same single-wall nanotube either free standing or lying on a substrate shows large broadening of the excitonic resonances with increase of oscillator strength, as well as stark weakening of polarization-dependent antenna effects, due to nanotube-substrate interaction.

  10. Measuring absolute frequencies beyond the GPS limit via long-haul optical frequency dissemination.

    PubMed

    Clivati, Cecilia; Cappellini, Giacomo; Livi, Lorenzo F; Poggiali, Francesco; de Cumis, Mario Siciliani; Mancini, Marco; Pagano, Guido; Frittelli, Matteo; Mura, Alberto; Costanzo, Giovanni A; Levi, Filippo; Calonico, Davide; Fallani, Leonardo; Catani, Jacopo; Inguscio, Massimo

    2016-05-30

    Global Positioning System (GPS) dissemination of frequency standards is ubiquitous at present, providing the most widespread time and frequency reference for the majority of industrial and research applications worldwide. On the other hand, the ultimate limits of the GPS presently curb further advances in high-precision, scientific and industrial applications relying on this dissemination scheme. Here, we demonstrate that these limits can be reliably overcome even in laboratories without a local atomic clock by replacing the GPS with a 642-km-long optical fiber link to a remote primary caesium frequency standard. Through this configuration we stably address the 1S0-3P0 clock transition in an ultracold gas of 173Yb, with a precision that exceeds the possibilities of a GPS-based measurement, dismissing the need for a local clock infrastructure to perform beyond-GPS high-precision tasks. We also report an improvement of two orders of magnitude in the accuracy on the transition frequency reported in literature.

  11. Ultrasonic oil-film thickness measurement: an angular spectrum approach to assess performance limits.

    PubMed

    Zhang, Jie; Drinkwater, Bruce W; Dwyer-Joyce, Rob S

    2007-05-01

    The performance of ultrasonic oil-film thickness measurement in a ball bearing is quantified. A range of different viscosity oils (Shell T68, VG15, and VG5) are used to explore the lowest reflection coefficient and hence the thinnest oil-film thickness that the system can measure. The results show a minimum reflection coefficient of 0.07 for both oil VG15 and VG5 and 0.09 for oil T68 at 50 MHz. This corresponds to an oil-film thickness of 0.4 microm for T68 oil. An angular spectrum (or Fourier decomposition) approach is used to analyze the performance of this configuration. This models the interaction of component plane waves with the measurement system and quantifies the effect of the key parameters (transducer aperture, focal length, and center frequency). The simulation shows that for a focused transducer the reflection coefficient tends to a limiting value at small oil-film thickness. For the transducer used in this paper it is shown that the limiting reflection coefficient is 0.05 and the oil-film measurement errors increase as the reflection coefficient approaches this value. The implications for improved measurement systems are then discussed.

  12. Absolute Ultraviolet Irradiance of the Moon from the LASP Lunar Albedo Measurement and Analysis from SOLSTICE (LLAMAS) Project

    NASA Astrophysics Data System (ADS)

    Snow, Martin; Holsclaw, Gregory M.; McClintock, William E.; Woods, Tom

    The Moon has been shown to be an extremely stable radiometric reference for calibration and long-term stability measurements of on-orbit sensors. The majority of the previous work on characterizing the lunar reflectance has been in the visible part of the spectrum using ground-based lunar images. The SOLar-STellar Irradiance Comparison Experiment (SOLSTICE) on the SOlar Radiation and Climate Experiment (SORCE) can be used to extend the lunar spectral irradiance dataset to include the 115-300 nm range. SOLSTICE can directly measure both the solar and lunar spectra from orbit, using the same optics and detectors. An observing campaign to map out the reflectance as a function of phase angle began in mid 2006 and continued through 2010. The geometry of SORCE's orbit is very favorable for lunar observations, and we have measurements spanning a range 0-170 ∘ in phase angle. In addition to Earth Observing Systems using the Moon for calibration, recent planetary missions have also made ultraviolet observations of the Moon during Earth flyby, and these SOLSTICE measurements can be useful in calibrating the absolute responsivity of those instruments as well.

  13. New Measurements of the Absolute Spectral Energy Distribution of Solar Radiation in the Range Double Lambda 650-1070 NM

    NASA Astrophysics Data System (ADS)

    Burlov-Vasilev, K. A.; Vasileva, I. E.; Matveev, Yu. B.

    1996-01-01

    Spectral measurements of the solar disk centre intensity for the near-IR region have been made at he Terskol High-Altitude Station in 1992. These measurements are the continuation of the program for the solar absolute spectral energy distribution investigation. Data published earlier are extended to the longwave spectral region up to 1070 nm. The special-purpose solar telescope SEF-1 was used. We compared the disk centre brightness with brightness of the calibrated region of the standard ribbon tungsten lamp. The atmospheric extinction was taken into account by the Bouguer method with simultaneous control of the atmosphere stability. The 1-nm integrals of the disk centre intensity in the range double lamda 650-1070 nm based on 5-day measurements in March-October 1992 are given. The uncertainty of these values is 2%. In regions with strong telluric absorption by oxygen and water-vapour bands, the reductions are made, using synthetic atmospheric absorption spectra computed on the basis of molecular parameter atlas HITRAN and the standard model atmosphere. By the use of the solar limb darkening coefficients the values of the solar flux at 1 A.U. were derived. Our measurements show the best agreement with the data of Makarova, Kharitonov, and Kazachevskaya as well as with the common data from Shaw and Frohlich. For lambda greater than 850 nm our data are systematically lower than the data by Neckel and Labs.

  14. Two-modality laser diode interferometer for high-accuracy measurement of long-range absolute distance

    NASA Astrophysics Data System (ADS)

    Wang, Bofan; Li, Zhongliang; Wang, Xiangzhao; Bu, Peng

    2010-08-01

    This paper presents a two-modality laser diode (LD) interferometer which combine as two-wavelength sinusoidal phase modulating (SPM) interferometer with a wavelength scanning interferometer (WSI) for measurement of distance over long range with high accuracy. Moreover, the intensity modulation due to power changes of LD is suppressed by appropriately choosing the modulation amplitude of injection current (IC) of LD. Triangle wave is used to modulate the IC of one LD with that of the other LD being constant at first. Thus the interferometer works as a wavelength scanning interferometer. An initial estimate of the distance can be obtained from the phase change of the interference signal. Then sinusoidal wave is used for modulating IC of both LDs to realize a two-wavelength SPM interferometer. However, the modulation of the IC of two LDs results in not only the wavelength modulation but also the intensity modulation. This intensity modulation will cause a measured phase error. To eliminate this error, SPM depths are appropriately chosen, therefore the distance to be measured can be accurately obtained with synthetic-wavelength algorithm. Experimental results indicate that an absolute distance measurement accuracy of 1μm can be achieved over the range of 40mm to 100mm.

  15. Measurement of the absolute CF2 concentration in a dielectric barrier discharge running in argon/fluorocarbon mixtures

    NASA Astrophysics Data System (ADS)

    Vinogradov, I. P.; Dinkelmann, A.; Lunk, A.

    2004-11-01

    The role of different CFx-radicals in plasma polymerization in fluorocarbon mixtures has not been determined yet. Therefore spectroscopic investigations of dielectric barrier discharges (DBDs) in argon/fluorocarbon mixtures at atmospheric pressure were conducted with the focus on measurement of the concentration of CFx-radicals. The following diagnostic procedures were applied: FTIR absorption spectroscopy to diagnose stable compounds in the discharge, optical emission spectroscopy of the DBD in the UV and visible range and measurement of the CF2 concentration by UV absorption spectroscopy. The DBD was running in argon with the following admixtures: CF4, C2F6, C2H2F4, C3F8, C3HF7, c-C4F8. The relative concentration of the CF3-radical and the absolute concentration of CF2 in Ar/fluorocarbon mixtures were measured by emission spectroscopy and by absorption and emission spectroscopy, respectively. Emission and absorption spectroscopy were performed simultaneously in combination with electrical measurements of the discharge characteristics. The influence of small amounts of hydrogen or oxygen added to the argon/fluorocarbon mixtures was investigated.

  16. Detrital illite crystals identified from crystallite thickness measurements in siliciclastic sediments

    USGS Publications Warehouse

    Aldega, L.; Eberl, D.D.

    2005-01-01

    Illite crystals in siliciclastic sediments are heterogeneous assemblages of detrital material coming from various source rocks and, at paleotemperatures >70 ??C, of superimposed diagenetic modification in the parent sediment. We distinguished the relative proportions of 2M1 detrital illite and possible diagenetic 1Md + 1M illite by a combined analysis of crystal-size distribution and illite polytype quantification. We found that the proportions of 1Md + 1M and 2M1 illite could be determined from crystallite thickness measurements (BWA method, using the MudMaster program) by unmixing measured crystallite thickness distributions using theoretical and calculated log-normal and/or asymptotic distributions. The end-member components that we used to unmix the measured distributions were three asymptotic-shaped distributions (assumed to be the diagenetic component of the mixture, the 1Md + 1M polytypes) calculated using the Galoper program (Phase A was simulated using 500 crystals per cycle of nucleation and growth, Phase B = 333/cycle, and Phase C = 250/ cycle), and one theoretical log-normal distribution (Phase D, assumed to approximate the detrital 2M1 component of the mixture). In addition, quantitative polytype analysis was carried out using the RockJock software for comparison. The two techniques gave comparable results (r2 = 0.93), which indicates that the unmixing method permits one to calculate the proportion of illite polytypes and, therefore, the proportion of 2M1 detrital illite, from crystallite thickness measurements. The overall illite crystallite thicknesses in the samples were found to be a function of the relative proportions of thick 2M1 and thin 1Md + 1M illite. The percentage of illite layers in I-S mixed layers correlates with the mean crystallite thickness of the 1Md + 1M polytypes, indicating that these polytypes, rather than the 2M1 polytype, participate in I-S mixed layering.

  17. Absolute Zero

    NASA Astrophysics Data System (ADS)

    Donnelly, Russell J.; Sheibley, D.; Belloni, M.; Stamper-Kurn, D.; Vinen, W. F.

    2006-12-01

    Absolute Zero is a two hour PBS special attempting to bring to the general public some of the advances made in 400 years of thermodynamics. It is based on the book “Absolute Zero and the Conquest of Cold” by Tom Shachtman. Absolute Zero will call long-overdue attention to the remarkable strides that have been made in low-temperature physics, a field that has produced 27 Nobel Prizes. It will explore the ongoing interplay between science and technology through historical examples including refrigerators, ice machines, frozen foods, liquid oxygen and nitrogen as well as much colder fluids such as liquid hydrogen and liquid helium. A website has been established to promote the series: www.absolutezerocampaign.org. It contains information on the series, aimed primarily at students at the middle school level. There is a wealth of material here and we hope interested teachers will draw their student’s attention to this website and its substantial contents, which have been carefully vetted for accuracy.

  18. Sea ice thickness in the Weddell Sea, inferred from upward looking sonar measurements

    NASA Astrophysics Data System (ADS)

    Behrendt, Axel; Dierking, Wolfgang; Witte, Hannelore

    2014-05-01

    Sea ice has been routinely monitored by satellites since 1979. However, thickness measurements of sea ice are still very sparse, especially in the Southern Hemisphere. Satellite altimetry still provides relatively uncertain estimates of ice thickness. Today, the only tool for monitoring sea ice thickness over long time periods with highest accuracy (5-10 cm) are moored upward looking sonars (ULS). The instruments measure the subsurface portion (draft) of the ice, which can be converted into total ice thickness. We present a data set of ULS time series from 13 positions in the Atlantic sector of the Southern Ocean (Weddell Sea), which were made in different years between 1990 and 2010. Monthly mean sea ice draft shows high interannual variability and can reach more than 3 m in the dynamic coastal regions of the eastern and western Weddell Sea. The thinnest ice is found away from the coast in the eastern Weddell Sea and rarely exceeds 1 m in the monthly mean. In single years the ULS data allow for a clear discrimination between thermodynamic ice growth and dynamic ice growth due to rafting and ridging of the floes. We demonstrate that the thermodynamic ice thickness can reach its theoretical maximum value of 1 m in the central Weddell basin. Despite significant gaps, the presented data set provides an important validation tool for satellite algorithms and sea ice models.

  19. Measuring the Thickness and Elastic Properties of Electroactive Thin-Film Polymers Using Platewave Dispersion Data

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; El-Azab, A.; Mal, Ajit K.

    1996-01-01

    Electroactive thin-film polymers are candidate sensors and actuators materials. They are also finding significant potential in muscle mechanisms and microelectromechanical systems (MEMS). In these applications, polymer thin films of thickness varying between 20 and 300 micrometers are utilized. The authors are currently studying the potential use of platewave dispersion curve measurements as an effective gauging tool for electroactive thin-film polymers.

  20. DNA nanofilm thickness measurement on microarray in air and in liquid using an atomic force microscope.

    PubMed

    Legay, Guillaume; Finot, Eric; Meunier-Prest, Rita; Cherkaoui-Malki, Mustapha; Latruffe, Norbert; Dereux, Alain

    2005-10-15

    The measurement of the thickness of DNA films on microarray as a function of the medium (liquid, air) is gaining importance for understanding the signal response of biosensors. Thiol group has been used to attach DNA strands to gold micropads deposited on silicon surface. Atomic force microscopy (AFM) was employed in its height mode to measure the change in the pad thickness and in its force mode to measure the indentation depth of the nanofilm. A good coherence between the height and force modes is observed for the film thickness in air. The adhesion force was found to be an alternative way to measure the surface coverage of the biolayer at nanoscopic scale. However the force analysis (compression, steric and electrostatic) provides baseline information necessary to interpret the AFM height image in liquid. Analysis of the film thickness distribution shows that the height of the DNA strands depends on both the DNA strand length (15-35 base pairs) and the environment (air, liquid). In air, longer strands lay down onto gold surface whereas the charge reversal of gold in liquid causes a repulsion of longer strands, which stand up.

  1. Association of digital cushion thickness with sole temperature measured with the use of infrared thermography.

    PubMed

    Oikonomou, G; Trojacanec, P; Ganda, E K; Bicalho, M L S; Bicalho, R C

    2014-07-01

    The main objective of this study was to investigate the association between digital cushion thickness and sole temperature measured by infrared thermography. Data were collected from 216 lactating Holstein cows at 4 to 10d in milk (DIM). Cows were locomotion scored and sole temperature was measured after claw trimming (a minimum delay of 3 min was allowed for the hoof to cool) using an infrared thermography camera. Temperature was measured at the typical ulcer site of the lateral digit of the left hind foot. Immediately after the thermographic image was obtained, the thickness of the digital cushion was measured by ultrasonography. Rumen fluid samples were collected with a stomach tube and sample pH was measured immediately after collection. Additionally, a blood sample was obtained and used for measurements of serum concentrations of β-hydroxybutyrate (BHBA), nonesterified fatty acids (NEFA), and haptoglobin. To evaluate the associations of digital cushion thickness with sole temperature, a linear regression model was built using the GLIMMIX procedure in SAS software (SAS Institute Inc., Cary, NC). Sole temperature was the response variable, and digital cushion thickness quartiles, locomotion score group, rumen fluid pH, rumen fluid sample volume, environmental temperature, age in days, and serum levels of NEFA, BHBA, and haptoglobin were fitted in the model. Only significant variables were retained in the final model. Simple linear regression scatter plots were used to illustrate associations between sole temperature (measured by infrared thermography at the typical ulcer site) and environmental temperature and between NEFA and BHBA serum levels and haptoglobin. One-way ANOVA was used to compare rumen fluid pH for different locomotion score groups and for different digital cushion quartiles. Results from the multivariable linear regression model showed that sole temperature increased as locomotion scores increased and decreased as digital cushion thickness

  2. Thick target measurement of the 40Ca(alpha,gamma)44Ti reaction rate

    SciTech Connect

    Sheets, S A; Burke, J T; Scielzo, N D; Phair, L; Bleuel, D; Norman, E B; Grant, P G; Hurst, A M; Tumey, S; Brown, T A; Stoyer, M

    2009-02-06

    The thick-target yield for the {sup 40}Ca({alpha},{gamma}){sup 44}Ti reaction has been measured for E{sub beam} = 4.13, 4.54, and 5.36 MeV using both an activation measurement and online {gamma}-ray spectroscopy. The results of the two measurements agree. From the measured yield a reaction rate is deduced that is smaller than statistical model calculations. This implies a smaller {sup 44}Ti production in supernova compared to recently measured {sup 40}Ca({alpha},{gamma}){sup 44}Ti reaction rates.

  3. Validation of Airborne FMCW Radar Measurements of Snow Thickness Over Sea Ice in Antarctica

    NASA Technical Reports Server (NTRS)

    Galin, Natalia; Worby, Anthony; Markus, Thorsten; Leuschen, Carl; Gogineni, Prasad

    2012-01-01

    Antarctic sea ice and its snow cover are integral components of the global climate system, yet many aspects of their vertical dimensions are poorly understood, making their representation in global climate models poor. Remote sensing is the key to monitoring the dynamic nature of sea ice and its snow cover. Reliable and accurate snow thickness data are currently a highly sought after data product. Remotely sensed snow thickness measurements can provide an indication of precipitation levels, predicted to increase with effects of climate change in the polar regions. Airborne techniques provide a means for regional-scale estimation of snow depth and distribution. Accurate regional-scale snow thickness data will also facilitate an increase in the accuracy of sea ice thickness retrieval from satellite altimeter freeboard estimates. The airborne data sets are easier to validate with in situ measurements and are better suited to validating satellite algorithms when compared with in situ techniques. This is primarily due to two factors: better chance of getting coincident in situ and airborne data sets and the tractability of comparison between an in situ data set and the airborne data set averaged over the footprint of the antennas. A 28-GHz frequency modulated continuous wave (FMCW) radar loaned by the Center for Remote Sensing of Ice Sheets to the Australian Antarctic Division is used to measure snow thickness over sea ice in East Antarctica. Provided with the radar design parameters, the expected performance parameters of the radar are summarized. The necessary conditions for unambiguous identification of the airsnow and snowice layers for the radar are presented. Roughnesses of the snow and ice surfaces are found to be dominant determinants in the effectiveness of layer identification for this radar. Finally, this paper presents the first in situ validated snow thickness estimates over sea ice in Antarctica derived from an FMCW radar on a helicopterborne platform.

  4. A Technique to Measure Energy Partitioning and Absolute Gas Pressures of Strombolian Explosions Using Doppler Radar at Erebus Volcano

    NASA Astrophysics Data System (ADS)

    Gerst, A.; Hort, M.; Kyle, P. R.; Voege, M.

    2008-12-01

    In 2005/06 we deployed three 24GHz (K-Band) continuous wave Doppler radar instruments at the crater rim of Erebus volcano in Antarctica. At the time there was a ~40 m wide, ~1000°C hot convecting phonolite lava lake, which was the source of ~0-6 Strombolian gas bubble explosions per day. We measured the velocities of ~50 explosions using a sample rate of 1-15 Hz. Data were downloaded in real-time through a wireless network. The measurements provide new insights into the still largely unknown mechanism of Strombolian eruptions, and help improve existing eruption models. We present a technique for a quasi in-situ measurement of the absolute pressure inside an eruption gas bubble. Pressures were derived using a simple eruption model and measured high resolution bubble surface velocities during explosions. Additionally, this technique allows us to present a comprehensive energy budget of a volcanic explosion as a time series of all important energy terms (i.e. potential, kinetic, dissipative, infrasonic, surface, seismic and thermal energy output). The absolute gas pressure inside rising expanding gas bubbles rapidly drops from ~3-10 atm (at the time when the lake starts to bulge) to ~1 atm before the bubble bursts, which usually occurs at radii of ~15-20m. These pressures are significantly lower than previously assumed for such explosions. The according internal energy of the gas agrees well with the observed total energy output. The results show that large explosions released about 109 to 1010 J each (equivalent to about 200-2000 kg of TNT), at a peak discharge rate frequently exceeding 109 W (the power output of a typical nuclear power plant). This dynamic output is mainly controlled by the kinetic and potential energy of the exploding magma shell, while other energy types were found to be much smaller (with the exception of thermal energy). Remarkably, most explosions at Erebus show two distinct surface acceleration peaks separated by ~0.3 seconds. This suggests

  5. High-accuracy absolute rotation rate measurements with a large ring laser gyro: establishing the scale factor.

    PubMed

    Hurst, Robert B; Mayerbacher, Marinus; Gebauer, Andre; Schreiber, K Ulrich; Wells, Jon-Paul R

    2017-02-01

    Large ring lasers have exceeded the performance of navigational gyroscopes by several orders of magnitude and have become useful tools for geodesy. In order to apply them to tests in fundamental physics, remaining systematic errors have to be significantly reduced. We derive a modified expression for the Sagnac frequency of a square ring laser gyro under Earth rotation. The modifications include corrections for dispersion (of both the gain medium and the mirrors), for the Goos-Hänchen effect in the mirrors, and for refractive index of the gas filling the cavity. The corrections were measured and calculated for the 16  m2 Grossring laser located at the Geodetic Observatory Wettzell. The optical frequency and the free spectral range of this laser were measured, allowing unique determination of the longitudinal mode number, and measurement of the dispersion. Ultimately we find that the absolute scale factor of the gyroscope can be estimated to an accuracy of approximately 1 part in 108.

  6. Simultaneous absolute measurements of principal angle and phase retardation with a new common-path heterodyne interferometer.

    PubMed

    Lo, Yu-Lung; Lai, Chun-Hau; Lin, Jing-Fung; Hsu, Ping-Feng

    2004-04-01

    This study demonstrates a new method for simultaneously measuring both the angle of the principal axis and the phase retardation of the linear birefringence in optical materials. We used a circular common-path interferometer (polariscope) as the basic structure modulated by an electro-optic (EO) modulator. An algorithm was developed to simultaneously measure the principal axis and the phase retardation of a lambda/4 or lambda/8 plate as a sample. In the case of a lambda/4 plate, the average absolute error of the principal axis is approximately 3.77 degrees, and that of the phase retardation is approximately 1.03 degrees (1.09%). The retardation error is within the 5% uncertainty range of a commercial wave plate. Fortunately, the nonlinear error caused by the reflection phase retardation of the beam splitter dose not appear in the new system. Therefore the error could be attributed to misalignment and defects in the EO modulator or the other optical components. As for the repeatability of this new common-path heterodyne interferometer, the average deviation for the principal axis is 0.186 degrees and the phase retardation is 0.356 degrees. For the stability, the average deviation for the principal axis is 0.405 degrees and the phase retardation is 0.635 degrees. The resolution of this new system is estimated to be approximately 0.5 degrees, and the principal axis and phase retardation could be measured up to pi and 2pi, respectively, without ambiguity.

  7. Improved measurement of the absolute branching fraction of D+→ bar{K}^0 μ +ν _{μ }

    NASA Astrophysics Data System (ADS)

    Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, H. Y.; Chen, J. C.; Chen, M. L.; Chen, S.; Chen, S. J.; Chen, X.; Chen, X. R.; Chen, Y. B.; Cheng, H. P.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fan, J. Z.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Farinelli, R.; Fava, L.; Fedorov, O.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, X. Y.; Gao, Y.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, R. P.; Guo, Y.; Guo, Y. P.; Haddadi, Z.; Hafner, A.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Y.; Huang, Z. L.; Hussain, T.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, L. W.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Kiese, P.; Kliemt, R.; Kloss, B.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kupsc, A.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, Lei; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Y. B.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Loehner, H.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Messchendorp, J. G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, L. Q.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Ripka, M.; Rong, G.; Rosner, Ch.; Ruan, X. D.; Sarantsev, A.; Savrié, M.; Schoenning, K.; Schumann, S.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shi, M.; Song, W. M.; Song, X. Y.; Sosio, S.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Tiemens, M.; Ullrich, M.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, W.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Wang, Z. Y.; Weber, T.; Wei, D. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, L. G.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. N.; Zhang, Y. T.; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, Q. W.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zotti, L.; Zou, B. S.; Zou, J. H.

    2016-07-01

    By analyzing 2.93 fb^{-1} of data collected at √{s}=3.773 GeV with the BESIII detector, we measure the absolute branching fraction B(D+→ bar{K}^0μ +ν _{μ })=(8.72 ± 0.07_stat. ± 0.18_sys.)%, which is consistent with previous measurements within uncertainties but with significantly improved precision. Combining the Particle Data Group values of B(D^0→ K^-μ ^+ν _μ ), B(D+→ bar{K}^0 e+ν e), and the lifetimes of the D^0 and D^+ mesons with the value of B(D+→ bar{K}^0 μ +ν _{μ }) measured in this work, we determine the following ratios of partial widths: Γ (D^0→ K^-μ ^+ν _μ )/Γ (D+→ bar{K}^0μ +ν _{μ })=0.963± 0.044 and Γ (D+→ bar{K}^0 μ +ν _{μ })/Γ (D+→ bar{K}^0 e+ν e)=0.988± 0.033.

  8. A Simple Empirical Equation to Calculate Cloud Optical Thickness Using Shortwave Broadband Measurements

    SciTech Connect

    Barnard, James C.; Long, Charles N.

    2004-07-01

    In this paper, we present an empirical equation that can be used to estimate shortwave cloud optical thickness from measurements and analysis of shortwave broadband irradiances. When applied to a time series of broadband observations, this method can predict cloud optical thickness distributions that are very similar to those obtained using the Min algorithm (Min and Harrison, 1996). When considering a number of geographically diverse sites, medians of equation-derived distributions and Min-derived distributions differ by less than 10%. The equation is designed for fully overcast skies, surface albedos less than 0.3, and the cosine of the solar zenith angle must be greater than 0.15.

  9. Film thickness measurements on five fluid formulations by the mercury squeeze film capacitance technique

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Johnson, R. L.; Hyslop, I.; Day, R.

    1976-01-01

    The thinning characteristics of five fluids were studied by measuring film thickness as a function of time. The mercury squeeze film capacitance technique was used. All tests were performed at room temperature. The synthetic hydrocarbon plus a nematic liquid crystal, N-(p-methoxybenzylidene)-p-butylaniline, thinned according to a Newtonian model and retained its bulk viscosity. The synthetic hydrocarbon plus a phosphonate antiwear additive and the synthetic hydrocarbon plus n-hexadecanol produced residual thick films. The synthetic hydrocarbon base fluids and the synthetic hydrocarbon plus a paraffinic resin displayed viscosity increases during thinning, but no residual films were formed.

  10. Non-contact high precision measurement of surface form tolerances and central thickness for optical elements

    NASA Astrophysics Data System (ADS)

    Lou, Ying

    2010-10-01

    The traditional contact measuring methods could not satisfy the current optical elements measuring requirements. Noncontact high precision measuring theory, principle and instrument of the surface form tolerances and central thickness for optical elements were studied in the paper. In comparison with other types of interferometers, such as Twyman-Green and Mach-Zehnder, a Fizeau interferometer has the advantages of having fewer optical components, greater accuracy, and is easier to use. Some relations among the 3/A(B/C), POWER/PV and N/ΔN were studied. The PV with POWER removed can be the reference number of ΔN. The chromatic longitudinal aberration of a special optical probe can be used for non-contanct central thickness measurement.

  11. Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets

    SciTech Connect

    Quiter, Brian J.; Ludewigt, Bernhard A.; Mozin, Vladimir V.; Wilson, Cody; Korbly, Steve

    2010-08-31

    Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.

  12. XRD measurement of mean thickness, thickness distribution and strain for illite and illite-smectite crystallites by the Bertaut-Warren-Averbach technique

    USGS Publications Warehouse

    Drits, V.A.; Eberl, D.D.; Srodon, J.

    1998-01-01

    A modified version of the Bertaut-Warren-Averbach (BWA) technique (Bertaut 1949, 1950; Warren and Averbach 1950) has been developed to measure coherent scattering domain (CSD) sizes and strains in minerals by analysis of X-ray diffraction (XRD) data. This method is used to measure CSD thickness distributions for calculated and experimental XRD patterns of illites and illite-smectites (I-S). The method almost exactly recovers CSD thickness distributions for calculated illite XRD patterns. Natural I-S samples contain swelling layers that lead to nonperiodic structures in the c* direction and to XRD peaks that are broadened and made asymmetric by mixed layering. Therefore, these peaks cannot be analyzed by the BWA method. These difficulties are overcome by K-saturation and heating prior to X-ray analysis in order to form 10-A?? periodic structures. BWA analysis yields the thickness distribution of mixed-layer crystals (coherently diffracting stacks of fundamental illite particles). For most I-S samples, CSD thickness distributions can be approximated by lognormal functions. Mixed-layer crystal mean thickness and expandability then can be used to calculate fundamental illite particle mean thickness. Analyses of the dehydrated, K-saturated samples indicate that basal XRD reflections are broadened by symmetrical strain that may be related to local variations in smectite interlayers caused by dehydration, and that the standard deviation of the strain increases regularly with expandability. The 001 and 002 reflections are affected only slightly by this strain and therefore are suited for CSD thickness analysis. Mean mixed-layer crystal thicknesses for dehydrated I-S measured by the BWA method are very close to those measured by an integral peak width method.

  13. Measurement of fundamental illite particle thicknesses by X-ray diffraction using PVP-10 intercalation

    USGS Publications Warehouse

    Eberl, D.D.; Nuesch, R.; Sucha, V.; Tsipursky, S.

    1998-01-01

    The thicknesses of fundamental illite particles that compose mixed-layer illite-smectite (I-S) crystals can be measured by X-ray diffraction (XRD) peak broadening techniques (Bertaut-Warren-Averbach [BWA] method and integral peak-width method) if the effects of swellinf and XRD background noise are eliminated from XRD patterns of the clays. Swelling is eliminated by intercalating Na-saturated I-S with polyvinylpyrrolidone having a molecular weightof 10,000 (PVP-10). Background is minimized by using polished metallic silicon wafers cut perpendicular to (100) as a substrate for XRD specimens, and by using a single-crystal monochromator. XRD measurements of PVP-intercalated diagenetic, hydro-thermal and low-grade metamorphic I-S indicate that there at least 2 type of crystallite thickness distribution shapes for illite fundamental particles, lognormal and asymptotic; that measurements of mean fundamental illite particle thicknesses made by various techniques (Bertaut-Warren-Averbach, integral peak width, fixed cation content, and transmission electron microscopy [TEM]) give comparable results; and that strain (small difference in layer thicknesses) generally has a Gaussian distribution in the lognormal-type illites, but is often absent in the asymptotic-type illites.

  14. Thermal Conductivity Measurement of Xe-Implanted Uranium Dioxide Thick Films using Multilayer Laser Flash Analysis

    SciTech Connect

    Nelson, Andrew T.

    2012-08-30

    The Fuel Cycle Research and Development program's Advanced Fuels campaign is currently pursuing use of ion beam assisted deposition to produce uranium dioxide thick films containing xenon in various morphologies. To date, this technique has provided materials of interest for validation of predictive fuel performance codes and to provide insight into the behavior of xenon and other fission gasses under extreme conditions. In addition to the structural data provided by such thick films, it may be possible to couple these materials with multilayer laser flash analysis in order to measure the impact of xenon on thermal transport in uranium dioxide. A number of substrate materials (single crystal silicon carbide, molybdenum, and quartz) containing uranium dioxide films ranging from one to eight microns in thickness were evaluated using multilayer laser flash analysis in order to provide recommendations on the most promising substrates and geometries for further investigation. In general, the uranium dioxide films grown to date using ion beam assisted deposition were all found too thin for accurate measurement. Of the substrates tested, molybdenum performed the best and looks to be the best candidate for further development. Results obtained within this study suggest that the technique does possess the necessary resolution for measurement of uranium dioxide thick films, provided the films are grown in excess of fifty microns. This requirement is congruent with the material needs when viewed from a fundamental standpoint, as this length scale of material is required to adequately sample grain boundaries and possible second phases present in ceramic nuclear fuel.

  15. Single tapered fiber tip for simultaneous measurements of thickness, refractive index and distance to a sample.

    PubMed

    Moreno-Hernández, Carlos; Monzón-Hernández, David; Hernández-Romano, Iván; Villatoro, Joel

    2015-08-24

    We demonstrate the capability of an air cavity Fabry-Perot interferometer (FPI), built with a tapered lead-in fiber tip, to measure three parameters simultaneously, distance, group refractive index and thickness of transparent samples introduced in the cavity. Tapering the lead-in fiber enhances the light coupling back efficiency, therefore is possible to enlarge the air cavity without a significant deterioration of the fringe visibility. Fourier transformation, used to analyze the reflected optical spectrum of our FPI, simplify the calculus to determine the position, thickness and refractive index. Samples made of 7 different glasses; fused silica, BK7, BalF5, SF2, BaF51, SF15, and glass slides were used to test our FPI. Each sample was measured nine times and the results for position, thickness and refractive index showed differences of ± 0.7%, ± 0.1%, and ± 0.16% respectively. The evolution of thickness and refractive index of a block of polydimethylsiloxane (PDMS) elastomer due to temperature changes in the range of 25°C to 90°C were also measured. The coefficients of the thermal expansion and thermo-optic estimated were α = 4.71x10(-4)/°C and dn/dT = -4.66 x10(-4) RIU/°C, respectively.

  16. Sea-ice thickness measurement based on the dispersion of ice swell.

    PubMed

    Marsan, David; Weiss, Jérome; Larose, Eric; Métaxian, Jean-Philippe

    2012-01-01

    The dispersion of flexural waves propagating in the Arctic sea ice cover is exploited in order to locally measure the ice thickness. The observed dispersion, for waves filtered in the 4-20 s period interval, at up to 4 broad-band seismometers deployed in Spring 2007 near the North Pole, is compared to a parameterized model that accounts for a complex wavefield made of a superposition of independent plane waves with different amplitudes and back-azimuth angles. The parameterization, that includes finding the best modeled ice thickness, is performed by using the cross-correlation functions between the seismometers. The ice thickness is estimated to 2.5 ± 0.2 m for the ~1 km-large floe the seismic stations were deployed on, which is coherent with other, independent measurements at this site. This study thus demonstrates the feasibility of using broad-band seismometers deployed on the sea-ice in order to passively measure the ice thickness, without requiring active sources nor human intervention.

  17. Measurement of the dead layer thickness in a p-type point contact germanium detector

    NASA Astrophysics Data System (ADS)

    Jiang, Hao; Yue, Qian; Li, Yu-Lan; Kang, Ke-Jun; Li, Yuan-Jing; Li, Jin; Lin, Shin-Ted; Liu, Shu-Kui; Ma, Hao; Ma, Jing-Lu; Su, Jian; Tsz-King Wong, Henry; Yang, Li-Tao; Zhao, Wei; Zeng, Zhi

    2016-09-01

    A 994 g mass p-type PCGe detector has been deployed during the first phase of the China Dark matter EXperiment, aiming at direct searches for light weakly interacting massive particles. Measuring the thickness of the dead layer of a p-type germanium detector is an issue of major importance since it determines the fiducial mass of the detector. This work reports a method using an uncollimated 133Ba source to determine the dead layer thickness. The experimental design, data analysis and Monte Carlo simulation processes, as well as the statistical and systematic uncertainties are described. A dead layer thickness of 1.02 mm was obtained based on a comparison between the experimental data and the simulated results. Supported by National Natural Science Foundation of China (10935005, 10945002, 11275107, 11175099)

  18. Space- and time-resolved resistive measurements of liquid metal wall thickness

    NASA Astrophysics Data System (ADS)

    Mirhoseini, S. M. H.; Volpe, F. A.

    2016-11-01

    In a fusion reactor internally coated with liquid metal, it will be important to diagnose the thickness of the liquid at various locations in the vessel, as a function of time, and possibly respond to counteract undesired bulging or depletion. The electrical conductance between electrodes immersed in the liquid metal can be used as a simple proxy for the local thickness. Here a matrix of electrodes is shown to provide spatially and temporally resolved measurements of liquid metal thickness in the absence of plasma. First a theory is developed for m × n electrodes, and then it is experimentally demonstrated for 3 × 1 electrodes, as the liquid stands still or is agitated by means of a shaker. The experiments were carried out with Galinstan, but are easily extended to lithium or other liquid metals.

  19. Optical coherence tomography of skin for measurement of epidermal thickness by shapelet-based image analysis

    NASA Astrophysics Data System (ADS)

    Weissman, Jesse; Hancewicz, Tom; Kaplan, Peter

    2004-11-01

    Optical coherence tomography (OCT) provides a non-invasive method for in-vivo imaging of sub-surface skin tissue. Many skin features such as sweat glands and blisters are clearly observable in OCT images. It seems therefore probable that OCT could be used for the detection and identification of lesions and skin cancers. These applications, however, have not been well developed. One area in dermatology where OCT has been applied is the measurement of epidermal thickness. OCT images are inherently noisy and measurements based on them require intensive manual processing. A robust method to automatically detect and measure features of interest is necessary to enable routine application of OCT. As a first step, we approach the seemingly straightforward problem of measuring epidermal thickness. In this paper we describe a novel shapelet-based image processing technique for the automatic identification of the upper and lower boundaries of the epidermis in living human skin tissue. These boundaries are used to measure epidermal thickness. To our knowledge, this is the first report of automated feature identification and measurement from OCT images of skin.

  20. Ultrasound semi-automated measurement of fetal nuchal translucency thickness based on principal direction estimation

    NASA Astrophysics Data System (ADS)

    Yoon, Heechul; Lee, Hyuntaek; Jung, Haekyung; Lee, Mi-Young; Won, Hye-Sung

    2015-03-01

    The objective of the paper is to introduce a novel method for nuchal translucency (NT) boundary detection and thickness measurement, which is one of the most significant markers in the early screening of chromosomal defects, namely Down syndrome. To improve the reliability and reproducibility of NT measurements, several automated methods have been introduced. However, the performance of their methods degrades when NT borders are tilted due to varying fetal movements. Therefore, we propose a principal direction estimation based NT measurement method to provide reliable and consistent performance regardless of both fetal positions and NT directions. At first, Radon Transform and cost function are used to estimate the principal direction of NT borders. Then, on the estimated angle bin, i.e., the main direction of NT, gradient based features are employed to find initial NT lines which are beginning points of the active contour fitting method to find real NT borders. Finally, the maximum thickness is measured from distances between the upper and lower border of NT by searching along to the orthogonal lines of main NT direction. To evaluate the performance, 89 of in vivo fetal images were collected and the ground-truth database was measured by clinical experts. Quantitative results using intraclass correlation coefficients and difference analysis verify that the proposed method can improve the reliability and reproducibility in the measurement of maximum NT thickness.

  1. Ultrasound-based measurement of liquid-layer thickness: A novel time-domain approach

    NASA Astrophysics Data System (ADS)

    Praher, Bernhard; Steinbichler, Georg

    2017-01-01

    Measuring the thickness of a thin liquid layer between two solid materials is important when the adequate separation of metallic parts by a lubricant film (e.g., in bearings or mechanical seals) is to be assessed. The challenge in using ultrasound-based systems for such measurements is that the signal from the liquid layer is a superposition of multiple reflections. We have developed an algorithm for reconstructing this superimposed signal in the time domain. By comparing simulated and measured signals, the time-of-flight of the ultrasonic pulse in a layer can be estimated. With the longitudinal sound velocity known, the layer thickness can then be calculated. In laboratory measurements, we validate successfully (maximum relative error 4.9%) our algorithm for layer thicknesses ranging from 30 μm to 200 μm. Furthermore, we tested our method in the high-temperature environment of polymer processing by measuring the clearance between screw and barrel in the plasticisation unit of an injection moulding machine. The results of such measurements can indicate (i) the wear status of the tribo-mechanical screw-barrel system and (ii) unsuitable process conditions.

  2. Label-free measurement of microbicidal gel thickness using low-coherence interferometry

    NASA Astrophysics Data System (ADS)

    Braun, Kelly E.; Boyer, Jeffrey D.; Henderson, Marcus H.; Katz, David F.; Wax, Adam

    2006-03-01

    Spectral-domain low-coherence interferometry (LCI) was used to measure the thickness of microbicidal gels applied to a cylindrical calibration test socket. Microbicides are topical formulations containing active ingredients targeted to inhibit specific pathogens that are currently under development for application to the epithelial lining of the lower female reproductive tract to combat sexually transmitted infections such as HIV. Understanding the deployment and drug delivery of these formulations is vital to maximizing their effectiveness. Previously, in vivo measurements of microbicidal formulation thickness were assessed using fluorescence measurements of fluorescein-labeled gels via an optical endoscope-based device. Here we present an LCI-based device that measures the thickness of a formulation without the use of any exogenous agents by analyzing the interference pattern generated between the reflections from the front and back surface of the sample. Results are presented that validate the effectiveness and performance of the LCI measurement in a clinically relevant system as compared to an existing fluorescence-based method. The impact of the new LCI-based design on in vivo measurements is discussed.

  3. Absolute measurements of the electronic transition moments of seven band systems of the C2 molecule. Ph.D. Thesis - York Univ., Toronto

    NASA Technical Reports Server (NTRS)

    Cooper, D. M.

    1979-01-01

    Electronic transition moments of seven C2 singlet and triplet band systems in the 0.2-1.2 micron spectral region were measured. The measurements were made in emission behind incident shock waves in C2H2-argon mixtures. Narrow bandpass radiometers were used to obtain absolute measurements of shock-excited C2 radiation from which absolute electronic transition moments are derived by a synthetic spectrum analysis. New results are reported for the Ballik-Ramsay, Phillips, Swan, Deslandres-d'Azambuja, Fox-Herzberg, Mulliken, and Freymark systems.

  4. Monte Carlo analysis of the influence of germanium dead layer thickness on the HPGe gamma detector experimental efficiency measured by use of extended sources.

    PubMed

    Chham, E; García, F Piñero; El Bardouni, T; Ferro-García, M Angeles; Azahra, M; Benaalilou, K; Krikiz, M; Elyaakoubi, H; El Bakkali, J; Kaddour, M

    2014-09-22

    We have carried out a study to figure out the influence of crystal inactive-layer thickness on gamma spectra measured by an HPGe detector. The thickness of this dead layer (DL) is not known (no information about it was delivered by the manufacturer) due to the existence of a transition zone where photons are increasingly absorbed. To perform this analyses a virtual model of a Canberra HPGe detector was produced with the aid of MCNPX 2.7 code. The main objective of this work is to produce an optimal modeling for our GPGe detector. To this end, the study included the analysis of the total inactive germanium layer thickness and the active volume that are needed in order to obtain the smallest discrepancy between calculated and experimental efficiencies. Calculations and measurements were performed for all of the radionuclides included in a standard calibration gamma cocktail solution. Different geometry sources were used: a Marinelli and two other new sources represented as S(1) and S(2). The former was used for the determination of the active volume, whereas the two latter were used for the determination of the face and lateral DL, respectively. The model was validated by comparing calculated and experimental full energy peak efficiencies in the 50-1900keV energy range. the results show that the insertion of the DL parameter in the modeling is absolutely essential to reproduce the experimental results, and that the thickness of this DL varies from one position to the other on the detector surface.

  5. Pre-corneal tear film thickness in humans measured with a novel technique

    PubMed Central

    Azartash, Kaveh; Kwan, Justin; Paugh, Jerry R.; Nguyen, Andrew Loc; Jester, James V.

    2011-01-01

    Purpose The purpose of this work was to gather preliminary data in normals and dry eye subjects, using a new, non-invasive imaging platform to measure the thickness of pre-corneal tear film. Methods Human subjects were screened for dry eye and classified as dry or normal. Tear film thickness over the inferior paracentral cornea was measured using laser illumination and a complementary metal–oxide–semiconductor (CMOS) camera. A previously developed mathematical model was used to calculate the thickness of the tear film by applying the principle of spatial auto-correlation function (ACF). Results Mean tear film thickness values (±SD) were 3.05 μm (0.20) and 2.48 μm (0.32) on the initial visit for normals (n=18) and dry eye subjects (n=22), respectively, and were significantly different (p<0.001, 2-sample t-test). Repeatability was good between visit 1 and 2 for normals (intraclass correlation coefficient [ICC]=0.935) and dry eye subjects (ICC=0.950). Tear film thickness increased above baseline for the dry eye subjects following viscous drop instillation and remained significantly elevated for up to approximately 32 min (n=20; p<0.05 until 32 min; general linear mixed model and Dunnett’s tests). Conclusions This technique for imaging the ocular surface appears to provide tear thickness values in agreement with other non-invasive methods. Moreover, the technique can differentiate between normal and dry eye patient types. PMID:21527997

  6. Reproducibility of Facial Soft Tissue Thickness Measurements Using Cone-Beam CT Images According to the Measurement Methods.

    PubMed

    Hwang, Hyeon-Shik; Choe, Seon-Yeong; Hwang, Ji-Sup; Moon, Da-Nal; Hou, Yanan; Lee, Won-Joon; Wilkinson, Caroline

    2015-07-01

    The purpose of this study was to establish the reproducibility of facial soft tissue (ST) thickness measurements by comparing three different measurement methods applied at 32 landmarks on three-dimensional cone-beam computed tomography (CBCT) images. Two observers carried out the measurements of facial ST thickness of 20 adult subjects using CBCT scan data, and inter- and intra-observer reproducibilities were evaluated. The measurement method of "perpendicular to bone" resulted in high inter- and intra-observer reproducibility at all 32 landmarks. In contrast, the "perpendicular to skin" method and "direct" method, which measures a distance between one point on bone and the other point on skin, presented low reproducibility. The results indicate that reproducibility could be increased by identifying the landmarks on hard tissue images, rather than on ST images, and the landmark description used in this study can be used in the establishment of reliable tissue depth data using CBCT images.

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

    SciTech Connect

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

    2011-07-20

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

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

    PubMed

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

    2011-07-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  10. Light attenuation in a semitransparent foam sheet—Thickness measurement for industrial use

    NASA Astrophysics Data System (ADS)

    Ueda, Masahiro; Mizuno, Sanae; Matsumura, Akio; Tohjyo, Fumio

    An optical method for measuring the thickness of heterogeneous materials has been studied. The method is based on the light attenuation theory. A complete system has been constructed in order to demonstrate the applicability of the present method for industrial use. The experimental set-up consists of semiconductor lasers, focusing lenses, photo-diodes serving as a power meter and a personal computer with an A/D converter for data acquisition. Averaging of numerous measurements is required in the present method because the heterogeneous cell structure of the foam material yields large fluctuations in transmitted light levels. The fluctuations can be reduced to below 1% of the transmitted light power by 80 times averaging. The error of the measurement is considered to be a few tens of micrometers in thickness. The present system is capable of sampling data at a rate of 400 Hz and has been successfully applied to a manufacturing process.

  11. Study on the measurement of thin film thickness with fringe scanning method

    NASA Astrophysics Data System (ADS)

    Su, Jun-hong; Shi, Ying; Liu, Bing-cai

    2012-10-01

    Optical interferometry is a proven high-precision measurement technology, this paper collect interference fringe pattern of the measured film with phase-shift and shear principle based on optical interferometry and digital image processing, obtain multiple interferogram through control phase shifter in the same step to strike the average phase value,then achieve thin film thickness measurement. The kernel of this technology is to obtain necessary phase parameter by processing interferogram with reasonable algorithm and software. Preprocessing the collected image, including noise elimination, skew correction and contrast enhancement to get clear interference fringe pattern, and strike the main phase value through phase shift algorithm. Phase unwrapping the interferogram as for the distribution in a rang of (-π,π) to restore a continuous wave front phase, get surface shape distribution and thickness information of the thin film. The results show that this method of measuring film thickness is not only having high processing precision, but also having the advantages of non-contact measurement.

  12. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections

    NASA Astrophysics Data System (ADS)

    Bensley, Jonathan Guy; de Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-04-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4‧,6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2–10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections.

  13. Measurement system for lens thickness based on low-coherent fiber-optic interferometry

    NASA Astrophysics Data System (ADS)

    Chen, Li; Wang, Junhua; Xu, Min

    2016-10-01

    A new non-contact and wide-range measurement system for lens thickness based on low-coherent interferometry was proposed in this paper. In this system the reference mirror was set moveable, and high-resolution grating ruler was utilized to record real-time position of mirror. Then lens central thickness was calculated on the basis of the relative distance between two interference fringes' peak. Compared with the traditional thickness measurement technology based on low-coherent interferometry the new method has made great progresses. Firstly beam splitting and interference were separated by use of several fiber couplers which realized appropriate intensity ratio of probe beam and reference beam, and enhanced the contrast of interference fringes. Then zoom lens was designed to improve intensity coupling efficiency between the fiber system and lens system. Finally conversion from optical signal to electronic signal was accomplished by using balance detection, which was good for improving the signal-to-noise ratio. In this paper, firstly the basic principle of measuring device was put forward, namely low-coherent interference technique. Then design of the measuring device and solution for the main problems was introduced in detail. Experimental results of device was given in the end of article, which proved that the relative error of measurement was less than 0.05%.

  14. Image processing techniques for measuring non-uniform film thickness profiles

    SciTech Connect

    Nitta, S.V.; Liu, An-Hong; Plawsky, J.L.; Wayner, P.C. Jr.

    1996-12-31

    The long term objective of this research program is to determine the fluid flow and drying characteristics of thin liquid/solid films using image processing techniques such as Image Analyzing Interferometry (IAI) and Image Scanning Ellipsometry (ISE). The primary purpose of this paper is to present experimental data on the effectiveness of IAI and ISE to measure nonuniform film thickness profiles. Steady-state, non-isothermal profiles of evaporating films were measured using IAI. Transient thickness profiles of a draining film were measured using ISE. The two techniques are then compared and contrasted. The ISE can be used to measure transient as well as steady-state profiles of films with thickness ranging from 1 nm to > 20 {mu}m, whereas IAI can be used to directly measure Steady-state and transient profiles of only films thicker than about 100 nm. An evaluation of the reflected intensity can be used to extend the use of the IAI below 100 nm.

  15. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections

    PubMed Central

    Bensley, Jonathan Guy; De Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-01-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4′,6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2–10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections. PMID:27048757

  16. Absolute Summ

    NASA Astrophysics Data System (ADS)

    Phillips, Alfred, Jr.

    Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .

  17. Whole-field thickness strain measurement using multiple camera digital image correlation system

    NASA Astrophysics Data System (ADS)

    Li, Junrui; Xie, Xin; Yang, Guobiao; Zhang, Boyang; Siebert, Thorsten; Yang, Lianxiang.

    2017-03-01

    Three Dimensional digital image correlation(3D-DIC) has been widely used by industry, especially for strain measurement. The traditional 3D-DIC system can accurately obtain the whole-field 3D deformation. However, the conventional 3D-DIC system can only acquire the displacement field on a single surface, thus lacking information in the depth direction. Therefore, the strain in the thickness direction cannot be measured. In recent years, multiple camera DIC (multi-camera DIC) systems have become a new research topic, which provides much more measurement possibility compared to the conventional 3D-DIC system. In this paper, a multi-camera DIC system used to measure the whole-field thickness strain is introduced in detail. Four cameras are used in the system. two of them are placed at the front side of the object, and the other two cameras are placed at the back side. Each pair of cameras constitutes a sub stereo-vision system and measures the whole-field 3D deformation on one side of the object. A special calibration plate is used to calibrate the system, and the information from these two subsystems is linked by the calibration result. Whole-field thickness strain can be measured using the information obtained from both sides of the object. Additionally, the major and minor strain on the object surface are obtained simultaneously, and a whole-field quasi 3D strain history is acquired. The theory derivation for the system, experimental process, and application of determining the thinning strain limit based on the obtained whole-field thickness strain history are introduced in detail.

  18. Absolute measurement of cerebral optical coefficients, hemoglobin concentration and oxygen saturation in old and young adults with near-infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We present near-infrared spectroscopy measurement of absolute cerebral hemoglobin concentration and saturation in a large sample of 36 healthy elderly (mean age, 85 ± 6 years) and 19 young adults (mean age, 28 ± 4 years). Non-invasive measurements were obtained on the forehead using a commercially a...

  19. Macular and retinal nerve fiber layer thickness in Japanese measured by Stratus optical coherence tomography.

    PubMed

    Oshitari, Toshiyuki; Hanawa, Katsuhiro; Adachi-Usami, Emiko

    2007-06-01

    The purpose of this study was to determine the thickness of the macula and the retinal nerve fiber layer (RNFL) in Japanese subjects by Stratus optical coherence tomography (OCT), and to compare the findings with the normative data of subjects from the United States of America (USA). Sixty-one eyes from 31 healthy subjects were used for the measurement of the macular thickness, and 60 eyes from 30 healthy subjects were used for the RNFL thickness measurements. The values obtained from the Japanese subjects were compared with the corresponding values in healthy subjects from the USA. The superior, nasal, temporal, and inferior macular sectors and the mean and inferior areas of the RNFL in the Japanese subjects were significantly thicker than the corresponding areas of normal subjects in the USA (272 +/- 13 vs 255 +/- 17 mum, 274 +/- 12 vs 267 +/- 16 mum, 262 +/- 12 vs 251 +/- 13 mum, 268 +/- 13 vs 260 +/- 15 mum; p < 0.0001, 104 +/- 11 vs 100 +/- 12 mum, 134 +/- 20 vs. 126 +/- 18 mum; p = 0.0167, 0.0047, respectively). In conclusion, the significantly thicker macular regions and RNFL in the Japanese indicate not only that there are racial differences in retinal thicknesses but also that the normative values provided by the Stratus OCT should not be used for different races.

  20. Helicopter-borne measurements of sea ice thickness, using a small and lightweight, digital EM system

    NASA Astrophysics Data System (ADS)

    Haas, Christian; Lobach, John; Hendricks, Stefan; Rabenstein, Lasse; Pfaffling, Andreas

    2009-03-01

    Sea ice is an important climate variable and is also an obstacle for marine operations in polar regions. We have developed a small and lightweight, digitally operated frequency-domain electromagnetic-induction (EM) system, a so-called EM bird, dedicated for measurements of sea ice thickness. It is 3.5 m long and weighs only 105 kg, and can therefore easily be shipped to remote places and operated from icebreakers and small helicopters. Here, we describe the technical design of the bird operating at two frequencies of f1 = 3.68 kHz and f2 = 112 kHz, and study its technical performance. On average, noise amounts to ± 8.5 ppm and ± 17.5 ppm for f1 and f2, respectively. Electrical drift amounts to 200 ppm/h and 2000 ppm/h for f1 and f2, during the first 0.5 h of operation. It is reduced by 75% after 2 h. Calibration of the Inphase and Quadrature ppm signals varies by 2 to 3%. A sensitivity study shows that all these signal variations do affect the accuracy of the ice thickness retrieval, but that it remains better than ± 0.1 m over level ice in most cases. This accuracy is also confirmed by means of comparisons of the helicopter EM data with other thickness measurements. The paper also presents the ice thickness retrieval from single-component Inphase data of f1.