WorldWideScience

Sample records for lens thickness measured

  1. Noncontact optical measurement of lens capsule thickness ex vivo

    Science.gov (United States)

    Ziebarth, Noel M.; Manns, Fabrice; Uhlhorn, Stephen; Parel, Jean-Marie

    2004-07-01

    Purpose: To design a non-contact optical system to measure lens capsule thickness in cadaver eyes. Methods: The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused onto the tissue using an aspheric lens (NA=0.68) mounted on a motorized translation stage. Light reflected from the sample is collected by the fiber coupler and sent to a silicon photodiode connected to a power meter. Peaks in the power signal are detected when the focal point of the aspheric lens coincides with the capsule boundaries. The capsule thickness is proportional to the distance between successive peaks. Anterior and posterior lens capsule thickness measurements were performed on 13 human, 10 monkey, and 34 New Zealand white rabbit lenses. The cadaver eyes were prepared for optical measurements by bonding a PMMA ring on the sclera. The posterior pole was sectioned, excess vitreous was removed, and the eye was placed on a Teflon slide. The cornea and iris were then sectioned. After the experiments, the lenses were excised, placed in 10% buffered formalin, and prepared for histology. Results: Central anterior lens capsule thickness was 9.4+/-2.9μm (human), 11.2+/-6.6μm (monkey), and 10.3+/-3.6μm (rabbit) optically and 14.9+/-1.6μm (human), 17.7+/-4.9μm (monkey), and 12.6+/-2.3μm (rabbit) histologically. The values for the central posterior capsule were 9.4+/-2.9μm (human), 6.6+/-2.5μm (monkey), and 7.9+/-2.3μm (rabbit) optically and 4.6+/-1.4μm (human), 4.5+/-1.2μm (monkey), and 5.7+/-1.7μm (rabbit) histologically. Conclusions: This study demonstrates that a non-contact optical system can successfully measure lens capsule thickness in cadaver eyes.

  2. Non-contact optical measurement of lens capsule thickness during simulated accommodation

    Science.gov (United States)

    Ziebarth, Noel; Manns, Fabrice; Acosta, Ana-Carolina; Parel, Jean-Marie

    2005-04-01

    Purpose: To non-invasively measure the thickness of the anterior and posterior lens capsule, and to determine if it significantly changes during accommodation. Methods: Anterior and posterior capsule thickness was measured on post-mortem lenses using a non-contact optical system using a focus-detection technique. The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused on the tissue surface using an aspheric lens (NA=0.68) mounted on a translation stage with a motorized actuator. Light reflected from the sample surface is collected by the fiber coupler and sent to a photoreceiver connected to a computer-controlled data acquisition system. Optical intensity peaks are detected when the aspheric lens is focused on the capsule boundaries. The capsule thickness is equal to the distance traveled between two peaks multiplied by the capsule refractive index. Anterior and posterior lens capsule thickness measurements were performed on 18 cynomolgus (age average: 6+/-1 years, range: 4-7 years) eyes, 1 rhesus (age: 2 years) eye, and 12 human (age average: 65+/-16, range: 47-92) eyes during simulated accommodation. The mounted sample was placed under the focusing objective of the optical system so that the light was incident on the center pole. Measurements were taken of the anterior lens capsule in the unstretched and the stretched 5mm states. The lens was flipped, and the same procedure was performed for the posterior lens capsule. Results: The precision of the optical system was determined to be +/-0.5um. The resolution is 4um and the sensitivity is 52dB. The human anterior lens capsule thickness was 6.0+/-1.2um unstretched and 4.9+/-0.9um stretched (p=0.008). The human posterior lens capsule was 5.7+/-1.2um unstretched and 5.7+/-1.4um stretched (p=0.974). The monkey anterior lens capsule thickness was 5.9+/-1.9um unstretched and 4.8+/-1.0um stretched (p=0.002). The monkey posterior lens capsule was 5

  3. Aligning and measuring the curvature and thickness of high-precision lens

    Science.gov (United States)

    Wu, Kun-Huan; Chang, Shenq-Tsong; Hsu, Ming-Ying; Huang, Ting-Ming; Hsu, Wei-Yao; Tseng, Shih-Feng

    2015-09-01

    The radius of curvature is one of the most important specifications for spherical optics [1]. There are several methods and devices currently on the market that can be used to measure it, including optical level, non-contact laser interferometer (Interferometer), a probe-contact profiler (Profilometer), the centering machine and three-point contact ball diameter meter (Spherometer). The amount that can be measured with a radius of curvature of the lens aperture range depends on the interferometer standard lens f / number and lens of R / number (radius of curvature divided by the clear aperture of the spherical surface ratio between them). Unfortunately, for lens with diameter greater than 300 mm, the device is limited by the size of the holding fixture lenses or space. This paper aims to provide a novel surface contour detection method and machine, named "CMM spherometry by probe compensation," to measure the radius and thickness of the curvature of the optical surface by a coordinate measurement machine (CMM). In order to obtain more accurate optimization results, we used probe and temperature compensation to discuss the effect. The trace samples and the measurement results of CMM and the centering machine, which has top and bottom autocollimators, are compared.

  4. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  5. Comparison of central corneal thickness and anterior chamber depth measurements using three imaging technologies in normal eyes and after phakic intraocular lens implantation.

    NARCIS (Netherlands)

    Doors, M.; Cruysberg, L.P.J.; Berendschot, T.T.; Brabander, J. De; Verbakel, F.; Webers, C.A.; Nuijts, R.M.

    2009-01-01

    BACKGROUND: The repeatability and interchangeability of imaging devices measuring central corneal thickness (CCT) and anterior chamber depth (ACD) are important in the assessment of patients considering refractive surgery. The purpose of this study was to investigate the agreement of CCT and ACD

  6. Coating thickness measuring device

    International Nuclear Information System (INIS)

    Joffe, B.B.; Sawyer, B.E.; Spongr, J.J.

    1984-01-01

    A device especially adapted for measuring the thickness of coatings on small, complexly-shaped parts, such as, for example, electronic connectors, electronic contacts, or the like. The device includes a source of beta radiation and a radiation detector whereby backscatter of the radiation from the coated part can be detected and the thickness of the coating ascertained. The radiation source and detector are positioned in overlying relationship to the coated part and a microscope is provided to accurately position the device with respect to the part. Means are provided to control the rate of descent of the radiation source and radiation detector from its suspended position to its operating position and the resulting impact it makes with the coated part to thereby promote uniformity of readings from operator to operator, and also to avoid excessive impact with the part, thereby improving accuracy of measurement and eliminating damage to the parts

  7. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  8. Influence of Apical Clearance on Mini-Scleral Lens Settling, Clinical Performance, and Corneal Thickness Changes.

    Science.gov (United States)

    Esen, Fehim; Toker, Ebru

    2017-07-01

    The purpose of this work was to define the timing and magnitude of scleral contact lens settling, the factors influencing settling, and to examine whether the amount of apical clearance has an impact on clinical performance or is associated with hypoxia-induced corneal changes. Eleven patients (22 eyes) with keratoconus were fitted with a mini-scleral lens (Esclera, Brazil). Three different lenses with successively greater sagittal depths were applied to achieve 3 levels of initial apical clearance: 100 to 200 μm (low), 200 to 300 μm (medium), and greater than 300 μm (high). Corneal apical clearance was measured at 15 min, 1, 2, 4, 6, and 8 hr with optical coherence tomography (OCT). Central corneal thickness was measured with OCT and Pentacam, in the morning and immediately after removal of the contact lens. Mean settling was 26.8±18.8 μm (42.7%) at 1 hr, 39.5±26.5 μm (62.9%) at 2 hr, 50.7±31.6 μm (80.8%) at 4 hr, 57.4±34.6 μm (91.4%) at 6 hr, and 62.8±38.4 μm (100%) at 8 hr. Settling rate was significantly lower in low apical clearance group (P=0.01). The smaller diameter lenses settled more (P=0.03). There was a slight statistically significant increase of 1.3% in central corneal thickness measured with OCT (P=0.03). Central corneal thickness measured with Pentacam at three locations increased slightly (P=0.001). Settling showed significant intrasubject and intersubject variations. The amount of corneal swelling and comfort scores did not differ significantly according to apical clearance. The average amount of settling was 62.8 μm after 8 hr, 80% of which occurred during the first 4 hr. Slight corneal swelling (1.3%) occurred after 8 hr of wear.

  9. Experimental and numerical evaluation of LNAPL lens and polluted capillary fringe thickness

    International Nuclear Information System (INIS)

    Chevalier, L.R.

    1998-01-01

    The effective remediation of light non-aqueous-phase liquid (LNAPL) in the subsurface is dependent on predicting the location and geometry of the lens near the tension-saturated pores of the capillary fringe. The objective of this study was to evaluate both the thickness of a lens of light nonaqueous phase liquid spill in the subsurface and the subsequent alteration of the capillary fringe. Two-dimensional (2D) experiments were conducted in a parallel plate glass tank (1 m x 1 m x 5 cm) using Ottawa sand and gasoline. An equation for predicting the vertical thickness based on the displacement pressure in the lateral direction was developed. The model and previously published vertical equilibrium models for predicting the thickness of a lens were tested. The model equations were also used to evaluate changes in the capillary fringe due to capillary pollution. The results provide a means to better understand the behavior of light nonaqueous phase liquids in the subsurface

  10. Accurate thickness measurement of graphene

    International Nuclear Information System (INIS)

    Shearer, Cameron J; Slattery, Ashley D; Stapleton, Andrew J; Shapter, Joseph G; Gibson, Christopher T

    2016-01-01

    Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications. A number of techniques exist to determine the thickness of graphene films including optical contrast, Raman scattering and scanning probe microscopy techniques. Atomic force microscopy (AFM), in particular, is used extensively since it provides three-dimensional images that enable the measurement of the lateral dimensions of graphene films as well as the thickness, and by extension the number of layers present. However, in the literature AFM has proven to be inaccurate with a wide range of measured values for single layer graphene thickness reported (between 0.4 and 1.7 nm). This discrepancy has been attributed to tip-surface interactions, image feedback settings and surface chemistry. In this work, we use standard and carbon nanotube modified AFM probes and a relatively new AFM imaging mode known as PeakForce tapping mode to establish a protocol that will allow users to accurately determine the thickness of graphene films. In particular, the error in measuring the first layer is reduced from 0.1–1.3 nm to 0.1–0.3 nm. Furthermore, in the process we establish that the graphene-substrate adsorbate layer and imaging force, in particular the pressure the tip exerts on the surface, are crucial components in the accurate measurement of graphene using AFM. These findings can be applied to other 2D materials. (paper)

  11. Nanometer-thick flat lens with adjustable focus

    Energy Technology Data Exchange (ETDEWEB)

    Son, T. V.; Haché, A. [Département de Physique et d' Astronomie, Université de Moncton, Moncton, New Brunswick, E1A 3E9 (Canada); Ba, C. O. F.; Vallée, R. [Centre Optique, Photonique et Laser (COPL) and Pavillon d' Optique-Photonique, Université Laval, Québec, Québec G1V 0A6 (Canada)

    2014-12-08

    We report laser beam focusing by a flat, homogeneous film with a thickness of less than 100 nm. The effect relies on refractive index changes occurring in vanadium dioxide as it undergoes a phase transition from insulator to metal. Phase front curvature is achieved by means of temperature gradients, and adjustable focal lengths from infinity to 30 cm are attained.

  12. Measuring Rind Thickness on Polyurethane Foam

    Science.gov (United States)

    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. Thickness and uniformity measurements of nuclear targets

    International Nuclear Information System (INIS)

    Xu Guoji; Meng Xiangjin; Luo Xinghua; Guan Shouren

    1987-06-01

    This paper introduces the methods of target thickness and uniformity measurements including weighing, α-particle thickness gauge, quartz thickness gauge, optical transmittance and Rutherford backscattering. An α-particle gauging which measures target thicknesses up to several μm is metioned. A fast thickness measurements for C, Au and Cu targets by spectrophotometer is given. A high sensitive quartz gauge which can measure minimum deposit of 0.04 μg/cm 2 is described. Thickness and impurity determinations by RBS with accuracy better than 5% are summarized

  14. Statistical simplex approach to primary and secondary color correction in thick lens assemblies

    Science.gov (United States)

    Ament, Shelby D. V.; Pfisterer, Richard

    2017-11-01

    A glass selection optimization algorithm is developed for primary and secondary color correction in thick lens systems. The approach is based on the downhill simplex method, and requires manipulation of the surface color equations to obtain a single glass-dependent parameter for each lens element. Linear correlation is used to relate this parameter to all other glass-dependent variables. The algorithm provides a statistical distribution of Abbe numbers for each element in the system. Examples of several lenses, from 2-element to 6-element systems, are performed to verify this approach. The optimization algorithm proposed is capable of finding glass solutions with high color correction without requiring an exhaustive search of the glass catalog.

  15. Card controlled beta backscatter thickness measuring instrument

    International Nuclear Information System (INIS)

    Schlesinger, J.

    1978-01-01

    An improved beta backscatter instrument for the nondestructive measurement of the thickness of thin coatings on a substrate is described. Included therein is the utilization of a bank of memory stored data representative of isotope, substrate, coating material and thickness range characteristics in association with a control card having predetermined indicia thereon selectively representative of a particular isotope, substrate material, coating material and thickness range for conditioning electronic circuit means by memory stored data selected in accord with the predetermined indicia on a control card for converting backscattered beta particle counts into indicia of coating thickness

  16. Greenland Radar Ice Sheet Thickness Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — Two 150-MHz coherent radar depth sounders were developed and flown over the Greenland ice sheet to obtain ice thickness measurements in support of PARCA...

  17. Model SH intelligent instrument for thickness measuring

    International Nuclear Information System (INIS)

    Liu Juntao; Jia Weizhuang; Zhao Yunlong

    1995-01-01

    The authors introduce Model SH Intelligent Instrument for thickness measuring by using principle of beta back-scattering and its application range, features, principle of operation, system design, calibration and specifications

  18. Wide band interferometry for thickness measurement

    Science.gov (United States)

    Costantino, Santiago; Martinez, Oscar E.; Torga, Jorge R.

    2003-04-01

    In this work we present the concept of wide band interferometry as opposed to white-light interferometry to introduce a thickness measurement method that gains precision when the bandwidth is reduced to an adequate compromise in order to avoid the distortions arising from the material dispersion. The use of the widest possible band is a well established dogma when the highest resolution is desired in distance measurements with white-light interferometry. We will show that the dogma falls when thickness measurements must be carried out due to material dispersion. In fact the precise knowledge of the frequency dependence of the refractive index is essential for adequate thickness retrieval from the optical experiments. The device we present is also useful to obtain the group refractive index that is necessary to calculate the absolute thickness value. As an example, we show the spreading of a silicone oil on a reference surface in real time.

  19. Uncertainty estimation of ultrasonic thickness measurement

    International Nuclear Information System (INIS)

    Yassir Yassen, Abdul Razak Daud; Mohammad Pauzi Ismail; Abdul Aziz Jemain

    2009-01-01

    The most important factor that should be taken into consideration when selecting ultrasonic thickness measurement technique is its reliability. Only when the uncertainty of a measurement results is known, it may be judged if the result is adequate for intended purpose. The objective of this study is to model the ultrasonic thickness measurement function, to identify the most contributing input uncertainty components, and to estimate the uncertainty of the ultrasonic thickness measurement results. We assumed that there are five error sources significantly contribute to the final error, these sources are calibration velocity, transit time, zero offset, measurement repeatability and resolution, by applying the propagation of uncertainty law to the model function, a combined uncertainty of the ultrasonic thickness measurement was obtained. In this study the modeling function of ultrasonic thickness measurement was derived. By using this model the estimation of the uncertainty of the final output result was found to be reliable. It was also found that the most contributing input uncertainty components are calibration velocity, transit time linearity and zero offset. (author)

  20. Glue Film Thickness Measurements by Spectral Reflectance

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Glue Film Thickness Measurements by Spectral Reflectance

    International Nuclear Information System (INIS)

    Marshall, B.R.

    2010-01-01

    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 (micro)m, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  2. Mathematical synthesis of the thickness profile of the waveguide Lüneburg lens using the adiabatic waveguide modes method

    Science.gov (United States)

    Ayryan, Edik; Dashitsyrenov, Genin; Laneev, Evgeniy; Lovetskiy, Konstantin; Sevastianov, Leonid; Sevastianov, Anton

    2017-04-01

    The paper describes the classical and generalized Luneburg lens in the 3D and planar waveguide implementation. We demonstrate the relation between the focusing inhomogeneity of the effective refractive index of waveguide Luneburg lens and the irregularity of the waveguide layer thickness generating this inhomogeneity. For the dispersion relation of the irregular thin-film waveguide in the model of adiabatic waveguide modes we solve the problem of mathematical synthesis and computer-aided design of the thickness profile of waveguide layer for the Luneburg thin-film generalized waveguide lens with a given focal length. The calculations are carried out in specially normalized coordinates convenient for computer calculations. The solution is compared with the one obtained using the cross-sections method.

  3. Mandibular thickness measurements in young dentate adults.

    Science.gov (United States)

    Beaty, Narlin B; Le, Thomas T

    2009-09-01

    To measure thicknesses in clinical landmark areas of the dentate mandibles of young men and women. Using standard radiologic software, we obtained mean (SD) thickness measurements at the inferior or posterior borders of the mandible at the following 7 surgically useful sites: (1) the symphysis, (2) a point halfway between the symphysis and the mental nerve, (3) the mental nerve, (4) a point halfway between the mental nerve and the facial artery notch, (5) the facial artery notch, (6) the angle vertex, and (7) the ramus-condylar neck border. University hospital. A total of 150 dentate men and 75 dentate women aged 18 to 30 years who had undergone computed tomography of the head and neck region during the period of December 20, 2006 to February 20, 2007. Thicknesses of 7 mandibular sites. Mean (SD) thicknesses at the 7 mandibular sites were as follows: symphysis, 14.03 (1.53) mm for men and 13.21 (1.46) mm for women; halfway between the symphysis and the mental nerve, 11.17 (1.37) mm for men and 10.00 (1.08) mm for women; mental nerve, 9.48 (1.28) mm for men and 8.72 (1.00) mm for women; halfway between the mental nerve and the facial artery notch, 10.33 (1.24) mm for men and 9.45 (0.92) mm for women; facial artery notch, 7.27 (0.82) mm for men and 7.10 (0.88) mm for women; angle vertex, 5.42 (0.90) mm for men and 5.39 (0.66) mm for women; and ramus-condylar neck border, 5.90 (0.86) mm for men and 5.85 (0.71) mm for women. Clinical landmark areas in young dentate mandibles have mean thicknesses with limited SDs. The thickness measurements obtained at the sites in this study provide practical reference information for mandibular reconstruction and bicortical screw length estimation.

  4. Cement thickness measurements in cased boreholes

    International Nuclear Information System (INIS)

    Wahl, J.S.; Schuster, N.A.

    1978-01-01

    Methods and apparatus are provided for logging a borehole having solid matter along at least a portion of the wall thereof. Gamma radiation is emitted from the borehole into the surrounding media, and the amount of radiation which returns to the borehole is measured by three detectors located at different distances from the source of radiation, so as to be primarily sensitive to radiation which has respectively penetrated to three different depths in the surrounding media. The thickness of the solid matter on the borehole wall is then determined from the three gamma radiation measurements

  5. Measuring coating thicknesses on continuously moving material

    International Nuclear Information System (INIS)

    Holler, J.H.; Stanton, W.B.; Spongr, J.J.; Joffe, B.B.; Raffelsberger, P.W.; Tiebor, J.E.

    1982-01-01

    A method and apparatus using radiation techniques for measuring coating thicknesses on continuously moving strip material without altering a predetermined path along which it travels. A shuttle carrying a measuring probe having a radioactive isotope source and a detection device is provided for reciprocation along a preselected segment of the path of the strip. The shuttle and the probe are releasably engaged with the strip and carried thereby for synchronous movement therewith in the forward direction during a measurement cycle, and are disengaged from the strip when no measurement is being made, the movement of the shuttle then being controlled by an independent drive mechanism, shown as a belt drive, which reciprocates the shuttle along the rails. A belt drives it forward more slowly than the strip, which then engages the shuttle to pull it at strip speed, allowed by a pulley clutch. (author)

  6. Advanced Metrologies for Topography and Thickness Measurements

    Science.gov (United States)

    Riou, G.; Acosta, P.; Darwin, M.; Kamenev, B.

    2011-11-01

    Despite its limitations, like the low through put, Atomic force microscopy (AFM) is in common use in the semiconductor industry for surface geometry characterization. Recent development in optical profilometry, Index Corrected Topography (ICT), further expands the technique by analysis of the collected interferograms to extract films parameters (thickness, for instance) and surface topography. This model based technique delivers literally complete information (e.g. topography, roughness, filmstack properties) of measured structure with sub-micron lateral resolution and angstrom vertical resolution. The approach is a strong asset since it allows contact less topography measurement of wafer surfaces. In this paper we will show how this specific metrology can meet the aforementioned stringent requirements. The comparison with both the AFM and the spectroscopic ellipsometry will be presented.

  7. A thick lens of fresh groundwater in the southern Lihue Basin, Kauai, Hawaii, USA

    Science.gov (United States)

    Izuka, Scot; Gingerich, Stephen

    2002-11-01

    A thick lens of fresh groundwater exists in a large region of low permeability in the southern Lihue Basin, Kauai, Hawaii, USA. The conventional conceptual model for groundwater occurrence in Hawaii and other shield-volcano islands does not account for such a thick freshwater lens. In the conventional conceptual model, the lava-flow accumulations of which most shield volcanoes are built form large regions of relatively high permeability and thin freshwater lenses. In the southern Lihue Basin, basin-filling lavas and sediments form a large region of low regional hydraulic conductivity, which, in the moist climate of the basin, is saturated nearly to the land surface and water tables are hundreds of meters above sea level within a few kilometers from the coast. Such high water levels in shield-volcano islands were previously thought to exist only under perched or dike-impounded conditions, but in the southern Lihue Basin, high water levels exist in an apparently dike-free, fully saturated aquifer. A new conceptual model of groundwater occurrence in shield-volcano islands is needed to explain conditions in the southern Lihue Basin. Résumé. Dans le sud du bassin de Lihue (Kauai, Hawaii, USA), il existe une épaisse lentille d'eau souterraine douce dans une vaste région à faible perméabilité. Le modèle conceptuel conventionnel pour la présence d'eau souterraine à Hawaii et dans les autres îles de volcans en bouclier ne rend pas compte d'une lentille d'eau douce si épaisse. Dans ce modèle conceptuel, les accumulations de lave dont sont formés la plupart des volcans en bouclier couvrent de vastes régions à relativement forte perméabilité, avec des lentilles d'eau douce peu épaisses. Dans le sud du bassin de Lihue, les laves remplissant le bassin et les sédiments constituent une région étendue à faible conductivité hydraulique régionale, qui, sous le climat humide du bassin, est saturée presque jusqu'à sa surface; les surfaces pi

  8. Highly sensitive straightness measurement system using a ball-lens

    International Nuclear Information System (INIS)

    Lee, Minho; Yang, Hyun-Ik; Cho, Nahm-Gyoo

    2016-01-01

    In this paper, a new and simple optical technique to accurately measure the straightness errors of a linear stage is proposed. To improve the performance, including the measurement sensitivity and resolution of the measurement system, and to simultaneously measure two-dimensional straightness errors (2D straightness errors), an optical system was designed using a laser, a retro-reflector, a ball-lens, and a two-dimensional position sensitive detector (2D PSD). The characteristics of the measurement system were analytically and experimentally investigated. A prototype measurement system was manufactured based on the investigated results, and the performances of this system have been tested. The measuring performance of the system was easily improved by about 12 times using the proposed technique and it can be further improved. It is shown that the proposed technique can easily and effectively improve the performance of a conventional straightness measurement system based on the geometric optical method using a PSD. (paper)

  9. Manual for target thickness measurement by alpha particle irradiation

    International Nuclear Information System (INIS)

    Dias, J.F.; Martins, M.N.

    1990-04-01

    A system is described for thin-target thickness measurement through the alpha particle energy loss when them traverse the target. It is also described the program used in the analysis of the target thickness. (L.C.) [pt

  10. [Macular thickness measured by optical coherence tomography in pseudoaphakic eyes with clear vs yellow implant].

    Science.gov (United States)

    Chamorro, E; Bonnin-Arias, C; Pérez-Carrasco, M J; Alvarez-Rementería, L; Villa-Collar, C; Armadá-Maresca, F; Sánchez-Ramos, C

    2014-04-01

    To study the use of optical coherence tomography (OCT), for measuring the macular thickness variations produced over time in elderly pseudophakic subjects implanted with a clear intraocular lens (IOL) in one eye, and a yellow IOL in the other eye. Macular thickness measurements were obtained in the 36 eyes of 18 subjects over 65 years, with cataracts surgically removed from both eyes and implanted with different absorbance (clear and yellow) IOLs in 2 separate surgeries. Stratus-OCT was used to determine the macular thickness in 2 sessions with 5 years of difference. After 5 years of follow-up, the eyes implanted with clear IOLs revealed a significant decrease in macular thickness. However, in eyes implanted with yellow IOLs the macular thickness remained stable. The mean overall decrease in macular thickness in eyes implanted with clear IOLs was 5 ± 8 μm (P=.02), and foveal thickness reduction was 10 ± 17 μm (P=.02). The macular thickness changes produced in eyes implanted with a yellow IOL differ from those with a clear IOL. These observation point to a possible protective effect of yellow IOL against the harmful effects of light in elderly pseudophakic subjects. However, studies with a longer follow-up are still needed to confirm that the protection provided by this IOL model is clinically significant. Copyright © 2010 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  11. Determination of optical parameters of a GRIN lens by intercept measurement

    Science.gov (United States)

    Zhang, Yufei; Xiong, Baoxing; Xu, Qinfeng; Guo, Changwei; Zhang, Guiju; Xu, Feng; Zou, Kuaisheng

    2018-03-01

    An experimental method is used to measure the optical parameters of a GRIN lens. The intrinsic properties of the lens are well characterized by measuring the intercept values of the different GRIN lenses. Firstly, the intercept equation is derived from the transmission matrix of the GRIN lens, and the measurement method is described in detail. Secondly, we design and make the optical path measuring system. Finally, the error analysis of the experimental results is presented, which shows the feasibility of the working principle and the experiment operation. The principle and equipment of this measuring method are relatively effective, which affords great practical significance for the measurement of the GRIN lens.

  12. Synthesis of the Thickness Profile of the Waveguide Layer of the Thin Film Generalized Waveguide Luneburg Lens

    Directory of Open Access Journals (Sweden)

    Ayryan E.A.

    2016-01-01

    Full Text Available A local variation in the thickness of the waveguide layer of integrated optics waveguide causes a local decrease of phase velocity, and hence bending of rays and of the wave front. The relationship of the waveguide layer thickness profile h (y, z with the distribution of the effective refractive index of the waveguide β (y, z is described in terms of a particular model of waveguide solutions of the Maxwell equations. In the model of comparison waveguides the support of the thickness irregularity of the waveguide layer Δh coincides with the support of inhomogeneity of the effective refractive index Δβ. A more adequate but more cumbersome model of the adiabatic waveguide modes allows them to mismatch supp Δh ⊃ supp Δβ. In this paper, we solve the problem of the Δh reconstruction on the base of given Δβ of the thin film generalized waveguide Luneburg lens in a model of adiabatic waveguide modes. The solution is found in the form of a linear combination of Gaussian exponential functions and in the form of a cubic spline for the cylindrically symmetric Δh (r and in the form of a cubic spline for Δβ (r.

  13. Pelvic floor muscle thickness measured by perineal ultrasonography

    DEFF Research Database (Denmark)

    Bernstein, Inge Thomsen; Juul, N; Grønvall, S

    1991-01-01

    Pelvic floor muscle thickness was assessed in nine healthy female physiotherapists by perineal sonography. All measurements were performed as triple-measurements. The aims were to assess the reliability of the measurements and to establish a reference material. The muscle thickness at rest...

  14. Tomographic method for measurement of the gradient refractive index of the crystalline lens. I. The spherical fish lens.

    Science.gov (United States)

    Acosta, Eva; Vazquez, Daniel; Garner, Leon; Smith, George

    2005-03-01

    We present an iterative tomographic algorithm to reconstruct refractive-index profiles for meridional planes of the lens of the spherical fish eye from measurements of deflection angles of refracted rays. Numerical simulations show that the algorithm allows accuracy up to the fourth decimal place, provided that the refractive index can be regarded as an analytical function of the radial coordinate and the experimental errors are neglected. An experimental demonstration is given by applying the algorithm to retrieve the refractive-index profile of a spherical fish lens. The method is conceptually simple and does not require matching of the index of the surrounding medium to that of the surface of the lens, and the related iterative algorithm rapidly converges.

  15. Thickness measurement by using cepstrum ultrasonic signal processing

    International Nuclear Information System (INIS)

    Choi, Young Chul; Yoon, Chan Hoon; Choi, Heui Joo; Park, Jong Sun

    2014-01-01

    Ultrasonic thickness measurement is a non-destructive method to measure the local thickness of a solid element, based on the time taken for an ultrasound wave to return to the surface. When an element is very thin, it is difficult to measure thickness with the conventional ultrasonic thickness method. This is because the method measures the time delay by using the peak of a pulse, and the pulses overlap. To solve this problem, we propose a method for measuring thickness by using the power cepstrum and the minimum variance cepstrum. Because the cepstrums processing can divides the ultrasound into an impulse train and transfer function, where the period of the impulse train is the traversal time, the thickness can be measured exactly. To verify the proposed method, we performed experiments with steel and, acrylic plates of variable thickness. The conventional method is not able to estimate the thickness, because of the overlapping pulses. However, the cepstrum ultrasonic signal processing that divides a pulse into an impulse and a transfer function can measure the thickness exactly.

  16. A framework of cloud supported collaborative design in glass lens moulds based on aspheric measurement

    Science.gov (United States)

    Zhu, Yongjian; Wang, Yu; Na, Jingxin; Zhi, Yanan; Fan, Yufeng

    2013-09-01

    Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD), computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module (FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM), optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.

  17. Thickness measurement of A-1 reactor caisson tube walls

    International Nuclear Information System (INIS)

    Prepechal, J.; Sladky, J.

    1974-01-01

    The equipment is described of measuring the thickness of caisson pipes built in the Bohunice A-1 reactor. The pulse-type ultrasonic thickness gauge is based on the reflection method using the double probe. The measurement accuracy is 0.1 mm. (J.B.)

  18. Pelvic floor muscle thickness measured by perineal ultrasonography

    DEFF Research Database (Denmark)

    Bernstein, Inge Thomsen; Juul, N; Grønvall, S

    1991-01-01

    Pelvic floor muscle thickness was assessed in nine healthy female physiotherapists by perineal sonography. All measurements were performed as triple-measurements. The aims were to assess the reliability of the measurements and to establish a reference material. The muscle thickness at rest...... and at contraction was 9.4 +/- 0.8 mm and 11.5 +/- 1.1 mm respectively (mean +/- SD). Contraction increased the thickness by 2.2 +/- 0.8 mm or 23 +/- 8%. The intra- and inter observer standard deviation of the estimate was in the range of 4-6%. In conclusion, we find the reliability of the measurements acceptable....

  19. Comparison of the biometric measurements obtained using noncontact optical biometers LenStar LS 900 and IOL Master V.5.

    Science.gov (United States)

    Kołodziejczyk, Wojciech; Gałecki, Tomasz; Łazicka-Gałecka, Monika; Szaflik, Jerzy

    2011-01-01

    such cases, additional ultrasound biometry should be performed. Keratometry results obtained using both devices should not be used alternatively because of the different measurement methods and different refraction indexes. The LenStar LS 900 device comparing to the IOL Master additionally enables pachymetry, macular retinal thickness, lens thickens and pupil diameter measurement. Accuracy of those measurements should be studied in the future.

  20. Stratospheric thickness determined directly from satellite radiance measurements.

    Science.gov (United States)

    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.

  1. Lens regeneration in juvenile and adult rabbits measured by image analysis.

    Science.gov (United States)

    Gwon, A E; Jones, R L; Gruber, L J; Mantras, C

    1992-06-01

    Secondary cataract growth commonly occurs after extracapsular cataract extraction. The proliferation of this regrowth occurs at rates related to many factors. In this study, the authors analyzed the amount of lens regeneration after endocapsular lens extraction that leaves the anterior and posterior capsules relatively intact. The analysis was performed in New Zealand albino rabbits with the aid of image analysis measurements in young and adult animals. The effect of low vacuum suction of the anterior capsule on the growth was determined. Lens regeneration was used as a measure of the growth potential of the leftover epithelial cells in the capsule bag. The results showed that lens regeneration was significantly faster in younger rabbits. However, low vacuum suction had no effect on the growth rate. Potential therapeutic agents for preventing secondary cataracts may be better analyzed with image analysis processing of lens regeneration, a precise and rapid measurement technique.

  2. Statistical Analyses of AY-101 Ultrasonic Measurements of Wall Thickness

    International Nuclear Information System (INIS)

    Weier, Dennis R.

    2002-01-01

    Tank AY-101 wall thicknesses have been measured using ultrasonic (UT) images. Interest is in using the available data to estimate a worst-case minimum wall thickness for regions of the tank that remain unexamined with the UT approach. Each UT image can provide the wall thickness at a very large number of pixels, but only the minimum value for each image is used in this work. Since the data arise in this manner, one of several candidate statistical extreme value distributions should successfully fit these reported minimum values. Given a set of multiple UT images and the resulting minimum measured wall thicknesses, extreme value distributions are fit to the data with subsequent extrapolations made to estimate the minimum measured wall thickness expected for the entire tank. Such a minimum estimate incorporates both the variability in wall thicknesses and the uncertainty associated with the measurement method. Uncertainties of the estimated parameters are also derived and used in propagation of variance methods to obtain confidence bounds on the estimated minimum measured wall thickness as well

  3. Accuracy of ultrasound-measured bladder wall thickness for the ...

    African Journals Online (AJOL)

    M.M. Ali

    measured urinary bladder wall thickness. (BWT) in the diagnosis of detrusor overactivity (DO). Subjects and methods: Patients who had undergone urodynamic testing due to irritative lower urinary tract symptoms (LUTS) were evaluated for ...

  4. Determination of gold coating thickness measurement by using EDXRF

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaian; Masliana Muslimin; Fadlullah Jili Fursani

    2005-01-01

    The paper relates a study on the development of an analysis procedure for measuring the gold coating thickness using EDXRF technique. Gold coating thickness was measured by relating the counts under the Au L? peak its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thickness. The calibration graph shows a straight line for thin coating measurement until 0.9 μm. Beyond this the relationship was not linear and this may be resulted from the self-absorption effect. Quantitative analysis was also performed on two different samples of gold coated jewelry and a phone connector. Result from the phone connector analysis seems to agree with the manufacturer gold coating value. From the analysis of gold-coated jewelry it had been able to differentiate the two articles as gold wash and gold electroplated. (Author)

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

    International Nuclear Information System (INIS)

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

    2007-01-01

    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

  6. Measurement of thickness of highly inhomogeneous crude oil slicks.

    Science.gov (United States)

    Cheemalapati, Surya; Forth, Heather P; Wang, Hao; Konnaiyan, Karthik Raj; Morris, Jeffrey M; Pyayt, Anna L

    2017-04-10

    As part of the Deepwater Horizon toxicity testing program, a number of laboratories generated oil slicks in the laboratory to study potential toxic effects of these oil slicks on aquatic organisms. Understanding the details of how these slicks affect aquatic organisms requires careful correlation between slick thickness and the observed detrimental effects. Estimating oil film thickness on water can be challenging since the traditional color-based technique used in the field is very imprecise. Also, as we demonstrate here, the films formed on the water surface are highly nonuniform on a microscale level, and thus uniform thin film thickness measurement techniques based on optical interference do not work. In this paper, we present a method that estimates the local thickness of weathered oil slicks formed on artificial seawater using light transmission and Beer-Lambert's law. Here, we demonstrate results of careful calibration together with the actual thickness estimation. Due to the heterogeneity of the slicks formed, we present slick thickness as a range of thicknesses collected from multiple points within the oil slick. In all the experiments we used oil samples provided by the Natural Resource Damage Assessment toxicity testing program for the Deepwater Horizon oil spill. Therefore, this study has an important practical value and successfully addresses unique challenges related to measurements involving complex, viscous, paste-like heterogeneous substances such as weathered crude oil.

  7. Comparison of Different Approaches for Measuring Tibial Cartilage Thickness

    Directory of Open Access Journals (Sweden)

    Maier Jennifer

    2017-07-01

    Full Text Available Osteoarthritis is a degenerative disease affecting bones and cartilage especially in the human knee. In this context, cartilage thickness is an indicator for knee cartilage health. Thickness measurements are performed on medical images acquired in-vivo. Currently, there is no standard method agreed upon that defines a distance measure in articular cartilage. In this work, we present a comparison of different methods commonly used in literature. These methods are based on nearest neighbors, surface normal vectors, local thickness and potential field lines. All approaches were applied to manual segmentations of tibia and lateral and medial tibial cartilage performed by experienced raters. The underlying data were contrast agent-enhanced cone-beam C-arm CT reconstructions of one healthy subject’s knee. The subject was scanned three times, once in supine position and two times in a standing weight-bearing position. A comparison of the resulting thickness maps shows similar distributions and high correlation coefficients between the approaches above 0.90. The nearest neighbor method results on average in the lowest cartilage thickness values, while the local thickness approach assigns the highest values. We showed that the different methods agree in their thickness distribution. The results will be used for a future evaluation of cartilage change under weight-bearing conditions.

  8. Optical methods for thickness measurements on thin metal films.

    Science.gov (United States)

    Pokrowsky, P

    1991-08-01

    The thickness and the dielectric constants of thin metal films on glass substrates are determined by two different methods. The first method is a combination of transmission and ellipsometer measurements (TELL method) and the second is based on attenuated total reflection (ATR method in the Kretschmann arrangement). For comparison, both methods are applied to gold films within a thickness range of 20-80 nm. Furthermore, the TELL method was applied to chromium films of thicknesses up to 150 nm. All experiments are done with a He-Ne laser at 633-nm wavelength.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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.

  10. The thickness measuring methods by means of radionuclides

    International Nuclear Information System (INIS)

    Henker, W.

    1974-01-01

    The thickness measuring devices RMM 24004 produced in German Democratic Republic are described. They consist of measuring probe and central unit. The measuring probe contains radiator and measuring head, which consists of radiation detector and electrometric amplifier. They utilize absorption or backscattering of 147 Pm, 85 Kr, 90 Sr/ 90 Y, 106 Ru/ 106 Rh or 137 Cs radiation in interaction with atoms of measured material. A survey of typical applications is given. (Z.M.)

  11. Focal length measurement of a varifocal liquid lens with capacitance detection

    Science.gov (United States)

    Noda, Kentaro; Binh-Khiem, Nguyen; Takei, Yusuke; Takahata, Tomoyuki; Matsumoto, Kiyoshi; Shimoyama, Isao

    2014-04-01

    This paper reports on a detailed deformation model of varifocal liquid lenses fabricated by Parylene-on-liquid-deposition (POLD), which can be applied to measure and adjust the focal length of such lenses without using extra sensors or sensing mechanisms. The lens was fabricated by encapsulating a liquid between a transparent electrode and a polymer film that was covered with a metal electrode. When voltage is applied to the two electrodes, the lens deforms due to the electrostatic force, and its focal length and the capacitance between the two electrodes change simultaneously. This characteristic enables the focal length of the lens to be adjusted and detected by measuring the capacitance change. The focal length of the fabricated varifocal liquid lens changed from 153.6 to 82.6 mm by applying 150-V. The focal length change of the liquid lens was calculated from the change in its capacitance. Finally, to confirm the efficiency of this varifocal liquid lens, we fabricated a confocal distance sensor using the lens for laser scanning and demonstrated that this system can be used to measure distances of 94-140 mm with an average error of 0.83 mm and a standard deviation of 0.77 mm.

  12. The current status of eye lens dose measurement in interventional cardiology personnel in Thailand.

    Science.gov (United States)

    Krisanachinda, Anchali; Srimahachota, Suphot; Matsubara, Kosuke

    2017-06-01

    Workers involved in interventional cardiology procedures receive high eye lens doses if radiation protection tools are not properly utilized. Currently, there is no suitable method for routine measurement of eye dose. In Thailand, the eye lens equivalent doses in terms of Hp(3) of the interventional cardiologists, nurses, and radiographers participating in interventional cardiology procedures have been measured at 12 centers since 2015 in the pilot study. The optically stimulated luminescence (OSL) dosimeter was used for measurement of the occupational exposure and the eye lens dose of 42 interventional cardiology personnel at King Chulalongkorn Memorial Hospital as one of the pilot centers. For all personnel, it is recommended that a first In Light OSL badge is placed at waist level and under the lead apron for determination of Hp(10); a second badge is placed at the collar for determination of Hp(0.07) and estimation of Hp(3). Nano Dots OSL dosimeter has been used as an eye lens dosimeter for 16 interventional cardiology personnel, both with and without lead-glass eyewear. The mean effective dose at the body, equivalent dose at the collar, and estimated eye lens dose were 0.801, 5.88, and 5.70 mSv per year, respectively. The mean eye lens dose measured by the Nano Dots dosimeter was 8.059 mSv per year on the left eye and 3.552 mSv per year on the right eye. Two of 16 interventional cardiologists received annual eye lens doses on the left side without lead glass that were higher than 20 mSv per year, the new eye lens dose limit as recommended by ICRP with the risk of eye lens opacity and cataract.

  13. Thickness measurement instrument with memory storage of multiple calibrations

    International Nuclear Information System (INIS)

    Lieber, S.; Schlesinger, J.; Lieber, D.; Baker, A.

    1979-01-01

    An improved backscatter instrument for the nondestructive measurement of coatings on a substrate is described. A memory having selectable memory areas, each area having stored intelligence available which is determinative of the shape of a functional plot of coating thickness versus backscatter counts per minute unique for each particular combination of emitting isotope, substrate material, coating material and physical characteristics of the measuring instrument. A memory selector switch connects a selected area of memory to a microprocessor operating under program control whereby the microprocessor reads the intelligence stored at the selected area and converts the backscattered count of the coating being measured into indicia of coating thickness

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

    NARCIS (Netherlands)

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

    2007-01-01

    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

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

    Science.gov (United States)

    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.

  16. High-precision thickness measurements using beta backscatter

    International Nuclear Information System (INIS)

    Heckman, R.V.

    1978-11-01

    A two-axis, automated fixture for use with a high-intensity Pm-147 source and a photomultiplier-scintillation beta-backscatter probe for making thickness measurements has been designed and built. A custom interface was built to connect the system to a minicomputer, and software was written to position the tables, control the probe, and make the measurements. Measurements can be made in less time with much greater precision than by the method previously used

  17. The head for coatings thickness measurement, especially for printed circuits

    International Nuclear Information System (INIS)

    Sazonow, M.; Kunicki, B.; Urbanski, P.

    1992-01-01

    The new construction of measuring head for coating thickness especially for printed circuits has been worked out. The measuring head have got the beta source and G-M detector mounted in movable seat. The change of detector position enables precision fixing of the detail in the diagram hole before the measurement. The measuring area can be observed in the mirror. After controlling the proper detail position the detector come back to their measuring position fixed by spring and then is ready to measure. 2 figs

  18. Highly accurate adaptive TOF determination method for ultrasonic thickness measurement

    Science.gov (United States)

    Zhou, Lianjie; Liu, Haibo; Lian, Meng; Ying, Yangwei; Li, Te; Wang, Yongqing

    2018-04-01

    Determining the time of flight (TOF) is very critical for precise ultrasonic thickness measurement. However, the relatively low signal-to-noise ratio (SNR) of the received signals would induce significant TOF determination errors. In this paper, an adaptive time delay estimation method has been developed to improve the TOF determination’s accuracy. An improved variable step size adaptive algorithm with comprehensive step size control function is proposed. Meanwhile, a cubic spline fitting approach is also employed to alleviate the restriction of finite sampling interval. Simulation experiments under different SNR conditions were conducted for performance analysis. Simulation results manifested the performance advantage of proposed TOF determination method over existing TOF determination methods. When comparing with the conventional fixed step size, and Kwong and Aboulnasr algorithms, the steady state mean square deviation of the proposed algorithm was generally lower, which makes the proposed algorithm more suitable for TOF determination. Further, ultrasonic thickness measurement experiments were performed on aluminum alloy plates with various thicknesses. They indicated that the proposed TOF determination method was more robust even under low SNR conditions, and the ultrasonic thickness measurement accuracy could be significantly improved.

  19. Imaging and thickness measurement of amorphous intergranular films using TEM

    International Nuclear Information System (INIS)

    MacLaren, I.

    2004-01-01

    Fresnel fringe analysis is shown to be unreliable for grain boundaries in yttrium-doped alumina: the determined thicknesses do not agree well with those measured from high resolution transmission electron microscopy (HRTEM), the asymmetry between under- and overfocus is very large, and Fresnel fringes are sometimes shown at boundaries which contain no amorphous film. An alternative approach to the analysis of HRTEM images of grain boundary films is demonstrated: Fourier filtering is used to remove the lattice fringes from the image thereby significantly enhancing the visibility of the intergranular films. The apparent film thickness shows a discrepancy between measurements from the original HRTEM image and the filtered image. It was shown that fringe delocalisation and diffuseness of the amorphous/crystalline interfaces will lead to a significant underestimate of the thickness in unprocessed HRTEM images. In contrast to this, the average thickness can be much more accurately measured from the Fourier-filtered image, provided the boundary is oriented accurately edge-on

  20. Computer vision based nacre thickness measurement of Tahitian pearls

    Science.gov (United States)

    Loesdau, Martin; Chabrier, Sébastien; Gabillon, Alban

    2017-03-01

    The Tahitian Pearl is the most valuable export product of French Polynesia contributing with over 61 million Euros to more than 50% of the total export income. To maintain its excellent reputation on the international market, an obligatory quality control for every pearl deemed for exportation has been established by the local government. One of the controlled quality parameters is the pearls nacre thickness. The evaluation is currently done manually by experts that are visually analyzing X-ray images of the pearls. In this article, a computer vision based approach to automate this procedure is presented. Even though computer vision based approaches for pearl nacre thickness measurement exist in the literature, the very specific features of the Tahitian pearl, namely the large shape variety and the occurrence of cavities, have so far not been considered. The presented work closes the. Our method consists of segmenting the pearl from X-ray images with a model-based approach, segmenting the pearls nucleus with an own developed heuristic circle detection and segmenting possible cavities with region growing. Out of the obtained boundaries, the 2-dimensional nacre thickness profile can be calculated. A certainty measurement to consider imaging and segmentation imprecisions is included in the procedure. The proposed algorithms are tested on 298 manually evaluated Tahitian pearls, showing that it is generally possible to automatically evaluate the nacre thickness of Tahitian pearls with computer vision. Furthermore the results show that the automatic measurement is more precise and faster than the manual one.

  1. High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography

    International Nuclear Information System (INIS)

    Robert M. Malone, Brent C. Frogget, Morris I. Kaufman, Aric Tibbits, Gene A. Capelle, Mike Grover, Gerald D. Stevens, William D. Turley

    2008-01-01

    Shock waves passing through a metal sample can produce ejecta particulates at a metal-vacuum interface. Holography records particle size distributions by using a highpower, short-pulse laser to freeze particle motion. The sizes of the ejecta particles are recorded using an in-line Fraunhofer holography technique. Because the holographic plate would be destroyed in this energetic environment, a high-resolution lens has been designed to relay the interference fringes to a safe environment. Particle sizes within a 12-mm-diameter, 5-mm-thick volume are recorded on holographic film. To achieve resolution down to 0.5 microns, ultraviolet (UV) light (in this case supplied by a tripled Nd:YAG laser) is needed. The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution and operates at f/0.85 will be described. To set up this lens system, a doublet lens is temporarily attached that enables operation with 532-nm (green) light and 1100 lp/mm resolution. Thus, the setup and alignment is performed with green light, but the dynamic recording is done with UV light. During setup, the 532-nm beam provides enough focus shift to accommodate the placement of a resolution pattern outside the ejecta volume; this resolution pattern does not interfere with the calibrated wires and pegs surrounding the ejecta volume. A television microscope archives images of resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens will be presented, and resolution variation through the 5-mm depth of field will be discussed

  2. Layer thickness measurement using the X-ray fluorescence principle

    International Nuclear Information System (INIS)

    Mengelkamp, B.

    1980-01-01

    Curium 244 having a gamma energy of about 15.5 keV is used as excitation emitter for contactless and continuous measuring of the thickness of metallic layers on iron strip. Soft gamma radiation is absorbed in matter according to the photo effect, so that X-ray fluorescence radiation is generated in the matter, which depends on the element and is radiated to all sides. For instance, it amounts for iron 6.4 keV and is measured with a specific ionisation chamber for this energy range. With increasing atomic number of the elements, the energy of fluorescence radiation increases and hence also the emission signal of the detector. The prerequisite for a usable measuring effect is an element distance of at least two and the thickness of the layer to be measured being in an optimum range. A signal dependent on the thickness of the layer is produced either by absorption of iron radiation (absorption method - aluminium and tin) or by build-up radiation of the material of the layer (emission method - zinc and lead). (orig./GSCH) [de

  3. DNA Measurement of Overlapping Cell Nuclei in Thick Tissue Sections

    Directory of Open Access Journals (Sweden)

    Liang Ji

    1997-01-01

    Full Text Available The paper describes an improved image analysis procedure for measuring the DNA content of cell nuclei in thick sections of liver tissue by absorption densitometry. Whereas previous methods only permitted the analysis of isolated nuclei, the new technique enables both isolated and overlapping nuclei to be measured. A 3D segmentation procedure determines whether each object is an isolated nucleus or a pair of overlapping nuclei; in the latter case the combined optical density is redistributed to the individual nuclei. A selection procedure ensures that only complete nuclei are measured.

  4. MEASUREMENT OF RNFL THICKNESS USING OCT IMAGES FOR GLAUCOMA DETECTION

    Directory of Open Access Journals (Sweden)

    Dhivyabharathi

    2013-08-01

    Full Text Available The thickness of retinal nerve fiber layer (RNFL is one of the pompous parameters for assessing the disease, Glaucoma. A substantial amount of vision can be lost before the patient becomes aware of any defect. Optical Coherence Tomography (OCT provides enhanced depth and clarity of viewing tissues with high resolution compared with other medical imaging devices. It examines the living tissue non-invasively. This paper presents an automatic method to find the thickness of RNFL using OCT images. The proposed algorithm first extracts all the layers present in the OCT image by texture segmentation using Gabor filter method and an algorithm is then developed to segment the RNFL. The thickness measurement of RNFL is automatically displayed based on pixel calculation. The calculated thickness values are compared with the original values obtained from hospital. The result shows that the proposed algorithm is efficient in segmenting the region of interest without manual intervention. The effectiveness of the proposed method is proved statistically by the performance analysis.

  5. Pelvic floor muscle thickness measured by perineal ultrasonography

    DEFF Research Database (Denmark)

    Bernstein, Inge Thomsen; Juul, N; Grønvall, S

    1991-01-01

    and at contraction was 9.4 +/- 0.8 mm and 11.5 +/- 1.1 mm respectively (mean +/- SD). Contraction increased the thickness by 2.2 +/- 0.8 mm or 23 +/- 8%. The intra- and inter observer standard deviation of the estimate was in the range of 4-6%. In conclusion, we find the reliability of the measurements acceptable....

  6. A planar-dimensions machine vision measurement method based on lens distortion correction.

    Science.gov (United States)

    Sun, Qiucheng; Hou, Yueqian; Tan, Qingchang; Li, Guannan

    2013-01-01

    Lens distortion practically presents in a real optical imaging system causing nonuniform geometric distortion in the images and gives rise to additional errors in the vision measurement. In this paper, a planar-dimensions vision measurement method is proposed by improving camera calibration, in which the lens distortion is corrected on the pixel plane of image. The method can be divided into three steps: firstly, the feature points, only in the small central region of the image, are used to get a more accurate perspective projection model; secondly, rather than defining a uniform model, the smoothing spline function is used to describe the lens distortion in the measurement region of image, and two correction functions can be obtained by fitting two deviation surfaces; finally, a measurement method for planar dimensions is proposed, in which accurate magnification factor of imaging system can be obtained by using the correction functions. The effectiveness of the method is demonstrated by applying the proposed method to the test of measuring shaft diameter. Experimental data prove that the accurate planar-dimensions measurements can be performed using the proposed method even if images are deformed by lens distortion.

  7. Measurement of the thickness of the bronchial epithelium

    International Nuclear Information System (INIS)

    Bowden, D.H.; Baldwin, F.

    1989-02-01

    Cancer of the lung in uranium miners is thought to be related to the inhalation of gaseous radon daughters which become attached to molecules of water vapour or to dust particles. Since, the depth of tissue penetration by alpha particles is short, the thickness of the epithelium that lines the bronchial tree may be a critical factor in the development of cancers at specific sites in the lung. The objectives of the present study were: 1) to measure the thickness of human bronchial epithelium; 2) to determine the distribution and depth of the nuclei of basal cells in the bronchial epithelium; and 3) to compare these parameters in groups of smokers and non-smokers. Twenty-nine surgically removed specimens of the lung were examined (26 smokers, 3 non-smokers). The specimens were fixed and prepared for examination by light and electron microscopy. Blocks of tissue were oriented so that the maximum number of bronchi were cut in cross-section; measurements included bronchi of all sizes from bronchial generations (1≥ 9.01 mm) diameter to the smallest bronchioles, generations 7 - 16 (0.26 - 2.0 mm). Comparison of measurements in smokers and non-smokers show no significant differences, so that the 29 cases are considered to represent a homogeneous group. With progressive divisions of the bronchi, the epithelium decreases in thickness. Of more importance are the figures relating to the distance from the cell surface to the underlying nucleus. Here too, with the exception of goblet cells, the measurements are significantly smaller in generations 7 - 16 than in generation 1

  8. Variations in retinal nerve fiber layer measurements on optical coherence tomography after implantation of trifocal intraocular lens.

    Science.gov (United States)

    García-Bella, Javier; Martínez de la Casa, José M; Talavero González, Paula; Fernández-Vigo, José I; Valcarce Rial, Laura; García-Feijóo, Julián

    2018-01-01

    To establish the changes produced after implantation of a trifocal intraocular lens (IOL) on retinal nerve fiber layer measurements performed with Fourier-domain optical coherence tomography (OCT). This prospective study included 100 eyes of 50 patients with bilateral cataract in surgical range, no other associated ocular involvement, refractive errors between +5 and -5 spherical diopters, and less than 1.5 D of corneal astigmatism. The eyes were operated by phacoemulsification with implantation of 2 different trifocal IOLs (FineVision and AT LISA tri 839MP) in randomized equal groups. Cirrus OCT and Spectralis OCT were performed before surgery and 3 months later. Both analyzed the thickness of the nerve fiber layer and thickness divided by quadrants (6 in case of Spectralis and 4 in case of Cirrus HD). The mean age of patients was 67.5 ± 5.8 years. The global nerve fiber layer thickness measured with Spectralis OCT was 96.77 μm before surgery and 99.55 μm after. With Cirrus OCT, the global thickness was 85.29 μm before surgery and 89.77 μm after. Statistically significant differences in global thickness measurements between preimplantation and postimplantation of the IOL were found with both OCT in the 2 groups. Statistically significant differences were also found in temporal and superior quadrants. The implantation of a diffractive trifocal IOL alters the results of the optic nerve fiber layer on Fourier-domain OCT in these patients, which should be taken into account in the posterior study of these patients.

  9. A new measurement method for effective aperture of thick pinhole

    International Nuclear Information System (INIS)

    Xie Hongwei; Zhang Jianhua; Zhang Faqiang; Li Linbo; Qi Jianmin; Chen Jinchuan; Chen Dingyang

    2014-01-01

    The Lucy-Richardson super resolution image processing technique, combined with the introduced virtual point spread function (PSF), was used to develop a measurement method of the processing precision of the superfine thick pinhole aperture. The principles of the technique were based on the known ideal image and degraded image. After the restoration and reconstruction of the degraded image with the introduced virtual point spread function (PSF), the comparison is made between the reconstructed image and the ideal image to judge the correctness of the virtual point spread function (PSF). During this process, the simulation of the effects of the point spread function (PSF) upon the image reconstruction was carried out at first. As indicated by the simulation, the ideal point spread function (PSF) used in the image restoration and reconstruction could provide ideal results of the image reconstruction. However, in the case of relatively bigger size of the point spread function (PSF), the reconstructed image would be obtained smaller than the ideal image. Besides, related experiments were carried out on the cobalt radiation sources. In the experiments, the aperture of the shielded collimator to restrict and align the radiation source was known to be l.0 mm, the thick pinholes respectively 0.7 mm and 0.45 mm in aperture were used for the imaging of the ϕl mm radiation source, and the radiation image was recorded in imaging plates 0.05 mm × O.05 mm in spatial resolution. Based on the hypothesis that the processing precision of the thick pinhole fulfill the experiment requirements, the point spread function obtained from the simulated computation was introduced into the restoration and reconstruction of the recorded images. At the area with an intensity of 50%, the thick pinhole with 0.7 mm aperture could provide homogenous image of the radiation source. However, the thick pinhole with 0.45 mm aperture provided an elliptical image with a major-minor axis ratio of 5 : 3

  10. Online terahertz thickness measurement in films and coatings

    Science.gov (United States)

    Duling, Irl N.; White, Jeffrey S.

    2017-02-01

    Pulsed terahertz systems are currently being deployed for online process control and quality control of multi-layered products for use in the building products and aerospace industries. While many laboratory applications of terahertz can allow waveforms to be acquired at rates of 1 - 40 Hz, online applications require measurement rates of in excess of 100Hz. The existing technologies of thickness measurement (nuclear, x-ray, or laser gauges) have rates between 100 and 1000 Hz. At these rates, the single waveform bandwidth must still remain at 2THz or above to allow thinner layers to be measured. In the applications where terahertz can provide unique capability (e.g. multi-layer thickness, delamination, density) long-term stability must be guaranteed within the tolerance required by the measurement. This can mean multi-day stability of less than a micron. The software that runs on these systems must be flexible enough to allow multiple product configurations, while maintaining the simplicity required by plant operators. The final requirement is to have systems that can withstand the environmental conditions of the measurement. This might mean qualification in explosive environments, or operation in hot, wet or dusty environments. All of these requirements can put restrictions on not only the voltage of electronic circuitry used, but also the wavelength and optical power used for the transmitter and receiver. The application of terahertz systems to online process control presents unique challenges that not only effect the physical design of the system, but can also effect the choices made on the terahertz technology itself.

  11. The Impact of Lens Opacity on SD-OCT Retinal Nerve Fiber Layer and Bruch's Membrane Opening Measurements Using the Anatomical Positioning System (APS).

    Science.gov (United States)

    Mauschitz, Matthias M; Roth, Felix; Holz, Frank G; Breteler, Monique M B; Finger, Robert P

    2017-05-01

    To evaluate the impact of lens opacity on retinal nerve fiber layer thickness (RNFLT) and Bruch's membrane opening (BMO) measurements. Fifty-nine randomly selected patients without any other relevant ocular pathology undergoing elective routine cataract surgery in two specialized eye clinics were enrolled. RNFLT, BMO area, and BMO minimum rim width (BMO-MRW) were assessed with the Heidelberg Engineering Spectralis OCT using the anatomical positioning system (APS) prior to and 1 day after cataract surgery using a ring scan at different eccentricities of the disc (3.5, 4.1 and 4.7 mm). Lens opacity was quantified using densitometry based on Scheimpflug images (Oculus Pentacam AXL). RNFLT, BMO area, and BMO-MRW were virtually identical before and following removal of the cataractous lens. This held when assessed overall, within the six sectors for the 3.5-mm scan, or at any other eccentricity. Baseline RNFLT was not associated with lens opacity. Using the APS, RNFLT remained unchanged following cataract surgery, contrary to results reported by previous studies. Our results imply that the APS may have contributed to more precise spectral-domain optical coherence measurements, minimizing the influence of cataract on RNFLT and BMO assessments in our cohort.

  12. Measurement of the through thickness compression of a battery separator

    Science.gov (United States)

    Yan, Shutian; Huang, Xiaosong; Xiao, Xinran

    2018-04-01

    The mechanical integrity of the separator is critical to the reliable operation of a battery. Due to its minimal thickness, compression experiments with a single/a few layers of separator are difficult to perform. In this work, a capacitance based displacement set-up has been developed for the measurement of the through thickness direction (TTD) compression stress-strain behavior of the separator and the investigation of its interaction with the electrode. The experiments were performed for a stack of two layers of Celgard 2400 separator, NMC cathode, and separator/NMC cathode/separator stack in both dry and wet (i.e. submersed in dimethyl carbonate DMC) conditions. The experimental results reveal that the separator compression modulus can be significantly affected by the presence of DMC. The iso-stress based rule of mixtures was used to compute the compressive stress-strain curve for the stack from that of the separator and NMC layer. The computed curve agreed with the experimental curve reasonably well up to about 0.16 strain but deviated significantly to a softer response at higher strains. The results suggest that, in the stack, the TTD compressive deformation of the separator is influenced by the NMC cathode.

  13. The use of ocular anatomical measurements using a rotating Scheimpflug camera to assist in the Esclera® scleral contact lens fitting process.

    Science.gov (United States)

    Weber, Sarah La Porta; Ambrósio, Renato; Lipener, César; Coral-Ghanem, Cleusa; Hofling-Lima, Ana Luisa

    2016-04-01

    To test for associations between Pentacam(®) derived topography variables and to evaluate the predictive power of those variables in relation to scleral contact lens (SCL) fit. Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo-SP, Brazil. Prospective observational non-randomised, non-comparative study. Forty-seven patients (63 eyes) were indicated for the use of Esclera(®) SCL. All patients underwent Scheimpflug imaging before the initial SCL evaluation. The following parameters were measured by Pentacam: corneal elevations, thickness, density, and anterior chamber depth (ACD). Correlations between the SCL parameters and the Pentacam measurements were analysed with Pearson's correlation coefficients. A simple linear regression model was created for each lens parameter using the most-correlated Pentacam variable. In the total group, the results show correlations between the SCL parameters and the corneal astigmatism, ACD and pentacam-measured corneal height (Hm), with p<0.001 each. In addition, an inverse correlation between the lens sagittal depth (LSD) and the anterior radii minimum was shown (p<0.001). In the keratoconus group, the results show correlations between the SCL parameters and ACD and Hm (p<0.001, each). An inverse correlation between the LSD and the total thickness corneal density average was also observed (p=0.003). There was a positive correlation between the LSD and ACD, even as LD and ACD in the keratoconus group. Thus, these results suggest that certain Pentacam measurements can be good predictors of the most appropriate Esclera lens to be fitted in keratoconus patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Measurement of thick film adhesion by an impact separation technique

    International Nuclear Information System (INIS)

    Snowden, W.E.; Aksay, I.A.

    1981-01-01

    The purpose of this study was to utilize a dynamic loading (impact separation) technique to determine absolute values for the force of adhesion required to separate a substrate/film interface into its two joining components. A principal advantage of the technique is that the force required for adhesive failure is applied directly at the interface by stress waves of relatively low amplitude, not by application of a force to the free surface of the film. Critical impact velocities required for separation of thick films from two types of substrates were measured. Values for force of adhesion were then calculated using a complex finite-difference computer code developed for analysis of a variety of dynamic problems

  15. Speed of Sound and Materials Thickness Measuring by Ultrasound

    Directory of Open Access Journals (Sweden)

    Carlos Dias Maciel

    2002-01-01

    Full Text Available Nowadays, ultrasound pulse-echo systems are commonly used as a diagnostic tool, due to its advantageous characteristics such as being a non-destructive analysis method and having a millimeter range resolution for the currently used frequencies. Considering these and other qualities, this study intends to develop a system for measuring and analyzing physical properties of some materials. Using a data acquisition system in a microcomputer, electrical (voltage pulses are generated to agitate a transducer that sends a pressure pulse towards the sample. This same transducer receives the echo reflected from the material, converts the mechanical energy into an electrical one, transforming it into information, which is processed later using a mathematical computer program. With this process, the values of the sound speed and the signal attenuation in the sample are obtained, plus its thickness with a minor error.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 -2 .K -1 and 130 μC.N -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 order to

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

    Energy Technology Data Exchange (ETDEWEB)

    Very, F.; Rosenkrantz, E.; Combette, P.; Ferrandis, J.Y. [University Montpellier, IES, UMR 5214, F-34000, Montpellier (France); CNRS, IES, UMR 5214, F-34000, Montpellier (France); Fourmentel, D.; Destouches, C.; Villard, J.F. [CEA, DEN, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St Paul lez Durance (France)

    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

  18. Lens of the eye: regulatory limits, measurement, dosimetry and medical control. Technical sheets of the SFRP

    International Nuclear Information System (INIS)

    Bordy, J.M.

    2016-01-01

    As the lens of the eye are a radio-sensitive tissue which can be affected by ionizing radiations, and as epidemiological studies lead to the proposition of a revision of their exposure limit, this sheet first recalls regulatory limits and quantities to be measured. It proposes an overview of industrial and medical situations associated with an exposure risk for lens of the eye. It presents the conditions for bearing a specific individual dosimeter, and the design of dosimeters aimed at a direct measurement. It discusses the characteristics and performance of individual protection equipment, and the criterion for the choice between a direct measurement and an indirect assessment of a characteristic value of exposure for photons and for electrons. It addresses the issues of classification and monitoring for a professional medical follow-up: description of the pathological risk, elements for a medical follow-up (examinations), classification and dose monitoring

  19. DEVICE FOR MEASURING OF THERMAL LENS PARAMETERS IN LASER ACTIVE ELEMENTS WITH A PROBE BEAM METHOD

    Directory of Open Access Journals (Sweden)

    A. N. Zakharova

    2015-01-01

    Full Text Available We have developed a device for measuring of parameters of thermal lens (TL in laser active elements under longitudinal diode pumping. The measurements are based on the probe beam method. This device allows one to determine sign and optical power of the lens in the principal meridional planes, its sensitivity factor with respect to the absorbed pump power and astigmatism degree, fractional heat loading which make it possible to estimate integral impact of the photoelastic effect to the formation of TL in the laser element. The measurements are performed in a linearly polarized light at the wavelength of 532 nm. Pumping of the laser element is performed at 960 nm that makes it possible to study laser materials doped with Yb3+ and (Er3+, Yb3+ ions. The precision of measurements: for sensitivity factor of TL – 0,1 m-1/W, for astigmatism degree – 0,2 m-1/W, for fractional heat loading – 5 %, for the impact of the photoelastic effect – 0,5 × 10-6 K-1. This device is used for characterization of thermal lens in the laser active element from an yttrium vanadate crystal, Er3+,Yb3+:YVO .

  20. Parched elasto hydrodynamic lubrication film thickness measurement in an instrument ball bearing

    Science.gov (United States)

    Kingsbury, E.; Schritz, B.; Prahl, J.

    1988-01-01

    Parched Elasto Hydrodynamic Lubricant (PEHL) film thickness in a large instrument ball bearing is measured by electrical capacitance across its ball set. Correlation is shown between changes in film thickness and changes in Basic Speed Ratio (BSR) measured at the same time. BSR is confirmed as a sensitive, non-intrusive measure of transients in film thickness in a real bearing.

  1. Dissecting the Gravitational lens B1608+656 : II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Auger, M. W.; Hilbert, S.; Blandford, R. D.; Koopmans, L. V. E.; Fassnacht, C. D.; Treu, T.

    2010-01-01

    Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the "time-delay distance" to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (1) new, deep

  2. Fiber-optic Raman probe couples ball lens for depth-selected Raman measurements of epithelial tissue

    OpenAIRE

    Mo, Jianhua; Zheng, Wei; Huang, Zhiwei

    2010-01-01

    In this study, we present a fiber-optic ball lens Raman probe design for improving depth-selected Raman measurements of epithelial tissue. The Monte Carlo simulation results show that tissue Raman collection efficiency can be improved by properly selecting the refractive index and the diameter of the ball lens for the Raman probe design and the depth-selectivity of Raman measurements can also be improved by either increasing the refractive index or reducing the diameter of the ball lens. An a...

  3. Carotid intima-media thickness measurement in cardiovascular screening programmes.

    Science.gov (United States)

    Plantinga, Yvonne; Dogan, Soner; Grobbee, Diederick E; Bots, Michiel L

    2009-12-01

    Support for the notion that a carotid intima-media thickness (CIMT) measurement is useful in individual cardiovascular risk prediction in addition to a risk function may come from studies showing that for an individual a high or low CIMT measurement leads to a correct shift from one to another risk category and this shift is followed by different treatment consequences. We set out to systematically review the published evidence by performing a PubMed search (2 March 2009). Out of 50 publications on CIMT and future events, 31 reported on the relation in the correct domain, [i.e. those free from symptomatic vascular disease or diabetes mellitus in which assessment of risk using a risk function (e.g. Framingham or SCORE) to base initiation of drug treatment upon is recommended]. Most studies reported relative risks (or equivalents) for the entire population only, and no information on relative risks within certain risk categories that may be of use to reclassify individuals based on combination of absolute and relative risks. No data on potential shifts of participants was presented. Eight studies specifically focused on the added value of CIMT in risk prediction. In seven studies the area under the curve (AUC) of a receiver operating characteristic was used to assess improvements in risk prediction. These analyses showed that addition of a CIMT measurement to established risk factors led to small and sometimes significant improvements in the AUC. However, change in AUC should not be the only parameter to rely on to judge the appropriateness of CIMT in risk stratification. In one study (n = 242), evidence was presented in participants with an intermediate Framingham risk score, a CIMT measurement above the 60th (men) and 80th (women) percentile of age-specific normal CIMT values, shifted participants above the threshold for initiation of drug therapy. Yet, the study was based on 24 events, and no information was presented on the proportion of participants correctly

  4. Mass thickness measurement of dual-sample by dual-energy X-rays

    International Nuclear Information System (INIS)

    Chen Mincong; Li Hongmei; Chen Ziyu; Shen Ji

    2008-01-01

    X-ray equivalent energy can be used to measure mass thicknesses of materials. Based on this, a method of mass thickness measurement of dual-sample was discussed. It was found that in the range of sample mass thickness under investigation, the equivalent mass attenuation coefficient of a component could be used to compute mass thicknesses of a dual-sample, with relative errors of less than 5%. Mass thickness measurement of a fish sample was performed, and the fish bone and flesh could be displayed separately and clearly by their own mass thicknesses. This indicates that the method is effective in mass thickness measurement of dual-sample of suitable thicknesses. (authors)

  5. Fiber-optic Raman probe couples ball lens for depth-selected Raman measurements of epithelial tissue.

    Science.gov (United States)

    Mo, Jianhua; Zheng, Wei; Huang, Zhiwei

    2010-06-28

    In this study, we present a fiber-optic ball lens Raman probe design for improving depth-selected Raman measurements of epithelial tissue. The Monte Carlo simulation results show that tissue Raman collection efficiency can be improved by properly selecting the refractive index and the diameter of the ball lens for the Raman probe design and the depth-selectivity of Raman measurements can also be improved by either increasing the refractive index or reducing the diameter of the ball lens. An appropriate arrangement of the Raman probe-tissue distance can also optimize the collection efficiency for depth-resolved Raman measurements. Experimental evaluation of a ball lens Raman probe design on a two-layer tissue phantom confirms the potential of the ball lens Raman probe design for efficient depth-selected measurement on epithelial tissue. This work suggests that the fiber-optic Raman probe coupled with a ball lens can facilitate the depth-selected Raman measurements of epithelial tissue, which may improve the diagnosis of epithelial precancer and early cancer at the molecular level.

  6. Non-invasive objective and contemporary methods for measuring ocular surface inflammation in soft contact lens wearers - A review.

    Science.gov (United States)

    Chao, Cecilia; Richdale, Kathryn; Jalbert, Isabelle; Doung, Kim; Gokhale, Moneisha

    2017-10-01

    Contact lens wear is one of the primary risk factors for the development of ocular surface inflammatory events. The purpose of this review is to examine and summarize existing knowledge on the mechanisms of contact lens related ocular surface inflammation and the evidence for the effectiveness of current objective methods to measure ocular surface inflammation. Contact lens wear is postulated to trigger an inflammatory response on the ocular surface due to mechanical, chemical, hypoxic stress, or by the introduction of microbes and their toxins. Apart from the traditional signs of inflammation, such as swelling, oedema, redness and heat, on the ocular surface, other methods to measure ocular surface inflammation in sub-clinical levels include tear inflammatory mediator concentrations, conjunctival cell morphology, and corneal epithelial dendritic cell density and morphology. Tear inflammatory mediator concentrations are up- or down-regulated during contact lens wear, with or without the presence of associated inflammatory events. There is higher conjunctival cell metaplasia observed with contact lens wear, but changes in goblet cell density are inconclusive. Dendritic cell density is seen to increase soon after initiating soft contact lens wear. The long term effects of contact lens wear on dendritic cell migration in the cornea and conjunctiva, including the lid wiper area, require further investigation. Currently patient factors, such as age, smoking, systemic diseases and genetic profile are being studied. A better understanding of these mechanisms may facilitate the development of new management options and strategies to minimize ocular surface inflammation related to contact lens wear. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  7. Measurement of the bremsstrahlung spectra generated from thick ...

    Indian Academy of Sciences (India)

    with those predicted by Monte-Carlo (MC) calculations using PENELOPE code. A close agreement between the ... cross-sections; Monte-Carlo simulation. PACS Nos 34.80.-i; 78.70.-g; 33.20. ... Quarles [13] proposed a model for calculating the thick target bremsstrahlung cross- sections for incident electrons having ...

  8. Measurement of central corneal thickness and pre-corneal tear film thickness of rabbits using the Scheimpflug system

    Directory of Open Access Journals (Sweden)

    Jing Dong

    2013-10-01

    Full Text Available AIM:To measure central corneal thickness (CCT and pre-corneal tear film thickness using the Galilei dual-Scheimpflug analyzer (GSA in New Zealand white rabbits.METHODS:Ten normal New Zealand white rabbits (20 eyes were included in this study. With the assistance of 0.1% fluorescein, the pre-corneal tear film can be well visualized. Both eyes of each rabbit were scanned once with the GSA pre- and post-instillation of 1μL 0.1% fluorescein. The difference between the two measurements of CCT (4-mm diameter was recorded as the pachymetric values of the central tear film.RESULTS:The CCT of pre- and post-instillation was 388.8±9.5μm and 407.0±10.5μm, respectively. After a paired t-test analysis, the central pre-corneal tear film thickness of 4mm diameter was 18.2±5.31μm with a 95% confidence interval of (15.7, 20.6μm (PCONCLUSION:GSA can be used to measure CCT and analyze central tear film thickness of rabbits with the help of fluorescein.

  9. Practicable methods for histological section thickness measurement in quantitative stereological analyses

    Science.gov (United States)

    Matenaers, Cyrill; Popper, Bastian; Rieger, Alexandra; Wanke, Rüdiger

    2018-01-01

    The accuracy of quantitative stereological analysis tools such as the (physical) disector method substantially depends on the precise determination of the thickness of the analyzed histological sections. One conventional method for measurement of histological section thickness is to re-embed the section of interest vertically to its original section plane. The section thickness is then measured in a subsequently prepared histological section of this orthogonally re-embedded sample. However, the orthogonal re-embedding (ORE) technique is quite work- and time-intensive and may produce inaccurate section thickness measurement values due to unintentional slightly oblique (non-orthogonal) positioning of the re-embedded sample-section. Here, an improved ORE method is presented, allowing for determination of the factual section plane angle of the re-embedded section, and correction of measured section thickness values for oblique (non-orthogonal) sectioning. For this, the analyzed section is mounted flat on a foil of known thickness (calibration foil) and both the section and the calibration foil are then vertically (re-)embedded. The section angle of the re-embedded section is then calculated from the deviation of the measured section thickness of the calibration foil and its factual thickness, using basic geometry. To find a practicable, fast, and accurate alternative to ORE, the suitability of spectral reflectance (SR) measurement for determination of plastic section thicknesses was evaluated. Using a commercially available optical reflectometer (F20, Filmetrics®, USA), the thicknesses of 0.5 μm thick semi-thin Epon (glycid ether)-sections and of 1–3 μm thick plastic sections (glycolmethacrylate/ methylmethacrylate, GMA/MMA), as regularly used in physical disector analyses, could precisely be measured within few seconds. Compared to the measured section thicknesses determined by ORE, SR measures displayed less than 1% deviation. Our results prove the applicability

  10. Central Corneal Thickness Measurement by Ultrasound versus Orbscan II

    Directory of Open Access Journals (Sweden)

    Amir Faramarzi

    2008-12-01

    Full Text Available

    PURPOSE: To compare Orbscan II and ultrasonic pachymetry for measurement of central corneal thickness (CCT in eyes scheduled for keratorefractive surgery. METHODS: CCT was measured using Orbscan II (Bausch & Lomb, USA and then by ultrasonic pachymetry (Tomey SP-3000, Tomey Ltd, Japan in 100 eyes of 100 patients with no history of ocular surgery scheduled for excimer laser refractive surgery. RESULTS: Mean CCT was 544.7±35.5 (range 453-637 µm by ultrasonic pachymetry versus 546.9±41.6 (range 435-648 µm measured by Orbscan II applying an acoustic factor of 0.92 (P=0.14. The standard deviation of measurements was greater with Orbscan pachymetry but the difference was not statistically significant. CONCLUSION: CCT measurements by Orbscan II (applying an acoustic factor and by ultrasonic pachymetry are not significantly different; however, when CCT readings by Orbscan II are in the lower range, it is advisable to recheck the measurements using ultrasonic pachymetry.

  1. Use of B-mode ultrasonography for measuring femoral muscle thickness in dogs

    Science.gov (United States)

    SAKAEDA, Kanako; SHIMIZU, Miki

    2016-01-01

    Assessment of muscle mass is important for evaluating muscle function and rehabilitation outcomes. Ultrasound has recently been successfully used to estimate muscle mass in humans by measuring muscle thickness. This study attempted to standardize procedures for measuring femoral muscle thickness ultrasonographically, as well as quantify the reliability and validity of ultrasound evaluations of muscle thickness compared to measurements made by magnetic resonance imaging (MRI) in dogs. We evaluated the quadriceps femoris (QF), biceps femoris (BF), semitendinosus (ST) and semimembranosus (SM) muscles of 10 clinically healthy Beagle dogs. Scans were taken in 5 different sections divided equally between the greater trochanter and proximal patella. MRI was performed, followed by T1-weighted and contrast-enhanced T1-weighted imaging. Muscle cross-sectional area (CSA) was measured with MRI, and muscle thickness was measured with MRI and ultrasonography. The thickness of the QF, BF and ST muscles as measured by ultrasound at slices 1–3 (from the proximal end to the middle of the femur), 2–4 (middle of the femur) and 2 (more proximal than the middle of the femur), respectively, was correlated with muscle thickness and CSA as measured by MRI. These sites showed a flat interface between muscle and transducer and were situated over belly muscle. No correlation between measurement types was seen in SM muscle. We must confirm this assessment method for various breeds, sizes, ages and muscle pathologies in dogs, thereby confirming that muscle thickness as measured ultrasonographically can reflect muscle function. PMID:26832997

  2. Comparison and interchangeability of macular thickness measured with Cirrus OCT and Stratus OCT in myopic eyes.

    Science.gov (United States)

    Wang, Geng; Qiu, Kun-Liang; Lu, Xue-Hui; Zhang, Ming-Zhi

    2015-01-01

    To investigate the difference of macular thickness measurements between stratus optical coherence tomography (OCT) and Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA) in the same myopic patient and to develop a conversion equation to interchange macular thickness obtained with these two OCT devices. Eighty-nine healthy Chinese adults with spherical equivalent (SE) ranging from -1.13 D to -9.63 D were recruited. The macular thickness was measured by Cirrus OCT and Stratus OCT. The correlation between macular thickness and axial length and the agreement between two OCT measurements were evaluated. A formula was generated to interchange macular thickness obtained with two OCT devices. Average macular thickness measured with Stratus OCT (r=-0.280, P=0.008) and Cirrus OCT (r=-0.224, P=0.034) were found to be negatively correlated with axial length. No statistically significant correlation was found between axial length and central subfield macular thickness (CMT) measured with Stratus OCT (r=0.191, P=0.073) and Cirrus OCT (r=0.169, P=0.113). The mean CMT measured with Cirrus OCT was 53.63±7.94 µm thicker than with Stratus OCT. The formula CMTCirrus OCT=78.328+0.874×CMTStratus OCT was generated to interchange macular thickness obtained with two OCT devices. Macular thickness measured with Cirrus OCT were thicker than with Stratus OCT in myopic eyes. A formula can be used to interchange macular thickness measured with two OCT devices in myopic eyes. Studies with different OCT devices and larger samples are warranted to enable the comparison of macular values measured with different OCT devices.

  3. Research on measurement of thickness and damage degree of coatings based on lock-in thermography

    Science.gov (United States)

    Zhang, Jin-Yu; Wu, Lan-Jie

    2017-12-01

    Coatings is widely used and plays an important role in modern equipment, but it is lack of effective and rapid detection methods. From coatings thickness measurement principle of lock-in thermography, this article proposed unique coatings equal thickness processing method and damage monitoring method. The experimental results show that the method can quickly and efficiently characterize the coating thickness uniformity and the damage degree.

  4. Study of thin film thickness measurement based on white light interference

    Science.gov (United States)

    Zheng, Yuanbo; Chu, Chunxiao; Wang, Xia

    2017-02-01

    One method for measuring thin film thickness was proposed in this paper, which based on white light interference. One parallel flat crystal was used to be the standard glass, and put another glass on it, to form one air wedge between them. The reflectance spectrum of two beams interference was measured by one spectrometer. By fitting the reflectance spectrum, wave numbers corresponding to every peak can be found, then using two beam interference theory, the air gap thickness at light incident point can be fitted. By measuring the air gap thickness at different positions, the flatness of measured surface also can be analyzed.

  5. A new attempt of measurement film thickness by x-ray diffractometry

    International Nuclear Information System (INIS)

    Kosaka, Masao; Kobayashi, Hideo

    1987-01-01

    In order to make film thickness measurements independent from the property or the structure of the film materials or the substrate, it is needed to adopt instead of directly utilizing the X-ray diffraction intensity, or attenuation information obtained from the substrate or film material, other new methods for measurement. Among the information obtained by X-ray diffraction, if intensity is excluded, others are F.W.H.M. and diffraction angle, only. If it is possible to investigate the film thickness dependency of the diffraction angle, it should be possible to measure the film thickness by diffraction angle. However, since diffraction angle has no film thickness dependency, it cannot be used directly for measurement. However, if we consider the principle of the X-ray diffractometer method, although it may be very slight, the substrate will be eccentric from the revolving center of the goniometer on account of the thickness of the film. If eccentricity occurs, this will cause changes in the diffraction angle. If we set the radius of the goniometer as R, diffraction angle θ, and the eccentricity from the revolving center of the specimen surface X, the deflection angle Δ2θ of 2θ may be expressed by Δ2θ = -2X · COSθ/R Thus, if X is caused by the film thickness, and by measuring the Δ2θ, it will be possible to measure the film thickness. As a result of the experiment, it was found that X-ray diffraction method can be used for the measurement of the film thickness of a few microns or above by utilizing the eccentricity caused by the film thickness. Especially it has the advantage of being able to measure thick films that X-rays will not penetrate, without being influenced by the chemical structure of the film or the substrates. (author)

  6. Quantitative materials analysis of micro devices using absorption-based thickness measurements

    International Nuclear Information System (INIS)

    Sim, L M; Wog, B S; Spowage, A C

    2006-01-01

    Preliminary work in designing an X-ray inspection machine with the capability of providing quantitative thickness analysis based on absorption measurements has been demonstrated. This study attempts to use the gray levels data to investigate the nature and thickness of occluded features and materials within devices. The investigation focused on metallic materials essential to semiconductor and MEMS technologies such as tin, aluminium, copper, silver, iron and zinc. The materials were arranged to simulate different feature thicknesses and sample geometries. The X-ray parameters were varied in-order to modify the X-ray energy spectrum with the aim of optimising the measurement conditions for each sample. The capability of the method to resolve differences in thicknesses was found to be highly dependent on the material. The thickness resolution with aluminium was the poorest due to its low radiographic density. The thickness resolutions achievable for silver and tin were significantly better and of the order of 0.015 mm and 0.025 mm respectively. From the linear relationship between the X-ray attenuation and sample thickness established, the energy dependent linear attenuation coefficient for each material was determined for a series of specific energy spectra. A decrease in the linear attenuation coefficient was observed as the applied voltage and thickness of the material increased. The results provide a platform for the development of a novel absorption-based thickness measurement system that can be optimised for a range of industrial applications

  7. Macular volume and central foveal thickness measurements in ...

    African Journals Online (AJOL)

    Ethical approval was obtained from the Ethics Review Board of Aminu Kano Teaching. Hospital in 2011. One hundred subjects were recruited into the study after administration and ... The system has an inbuilt algorithm to generate the measured parameters. The findings were saved on the system and printed copies made.

  8. Revisited the mathematical derivation wall thickness measurement of pipe for radiography

    Energy Technology Data Exchange (ETDEWEB)

    Hamzah, A.R.; Amir, S.M.M. [Non Destructive Testing(NDT) Group, Industrial Technology Div., Malaysian Nuclear Agency, Selangor (Malaysia)

    2007-07-01

    Wall thickness measurement of pipe is very important of the structural integrity of the industrial plant. However, the radiography method has an advantage because the ability of penetrating the insulated pipe. This will have economic benefit for industry. Moreover, the era of digital radiography has more advantages because the speed of radiographic work, less exposure time and no chemical used for film development. Either the conventional radiography or digital radiology, the wall thickness measurement is using the tangential radiography technique (TRT). In case, of a large diameter, pipe (more than inches) the determination maximum penetration wall thickness must be taken into the consideration. This paper is revisited the mathematical derivation of the determination of wall thickness measurement based on tangential radiography technique (TRT). The mathematical approach used in this derivation is the Pythagoras theorem and geometrical principles. In order to derive the maximum penetration wall thickness a similar approach is used. (authors)

  9. Selection of the ''best'' model for converting beta backscatter count readings into thickness measurements

    International Nuclear Information System (INIS)

    Smiriga, N.G.

    1976-01-01

    This report compares two models for converting beta backscatter count readings into thickness measurements. The necessary formulas to be used in an unweighted and weighted regression analysis are listed. The question of whether one should perform a regression analysis using the five available standard thicknesses or whether one should, in addition to these standard thicknesses, use zero as a standard thickness is decided. A weighted regression analysis is compared with an unweighted one for each model. The ''best'' model is selected, and the conclusions of the analysis are presented

  10. Measuring Spatiotemporal Features of Land Subsidence, Groundwater Drawdown, and Compressible Layer Thickness in Beijing Plain, China

    OpenAIRE

    Yongyong Li; Huili Gong; Lin Zhu; Xiaojuan Li

    2017-01-01

    Beijing is located on multiple alluvial-pluvial fans with thick Quaternary unconsolidated sediments. It has suffered serious groundwater drawdown and land subsidence due to groundwater exploitation. This study aimed to introduce geographical distribution measure methods into land subsidence research characterizing, geographically, land subsidence, groundwater drawdown, and compressible layer thickness. Therefore, we used gravity center analysis and standard deviational ellipse (SDE) methods i...

  11. Simultaneous Measurement of Ultrasonic Velocity and Thickness of Isotropic and Homogeneous Solids Using Two Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ki; Kwon, Jin O; Kim, Young H. [Korea Inspection and Engineering Co., Seoul (Korea, Republic of)

    1999-10-15

    Ultrasonic pulse-echo methods measuring the transit time through specimens have been widely used in determination of ultrasonic velocity and thickness of specimens. Usually, to determine the velocity of the ultrasonic. Tthe transit time of the ultrasonic pulse through specimen is measured by using the ultrasonic measuring equipment such as the oscilloscope including ultrasonic pulser/receiver and the thickness of the specimen is measured by using the length measuring instrument such as micrometer or vernier calipers etc., i. e. each parameter is measured by using each measuring method. In the case of the measuring the thickness of a specimen by using the ultrasonics. the ultrasonic equipment, which measure the thickness, such as the ultrasonic thickness gauge must be calibrated by using the reference block of which the ultrasonic velocity is known beforehand. In the present work, we proposed a new method for simultaneous measurement of ultrasonic velocity and thickness without reference blocks. Experimental results for several specimens show that proposed method have good agreements with those by traditional ultrasonic method

  12. A semi-empirical method for measuring thickness of pipe-wall using gamma scattering technique

    International Nuclear Information System (INIS)

    Vo Hoang Nguyen; Hua Tuyet Le; Le Dinh Minh Quan; Hoang Duc Tam; Le Bao Tran; Tran Thien Thanh; Tran Nguyen Thuy Ngan; Chau Van Tao; VNUHCM-University of Science, Ho Chi Minh City; Huynh Dinh Chuong

    2016-01-01

    In this work, we propose a semi-empirical method for determining the thickness of pipe-wall, of which the determination is performed by combining the experimental and Monte Carlo simulation data. The testing measurements show that this is an efficient method to measure the thickness of pipe-wall. In addition, this work also shows that it could use a NaI(Tl) scintillation detector and a low activity source to measure the thickness of pipe-wall, which is simple, quick and high accuracy method. (author)

  13. Reliability assessment for thickness measurements of pipe wall using probability of detection

    International Nuclear Information System (INIS)

    Nakamoto, Hiroyuki; Kojima, Fumio; Kato, Sho

    2013-01-01

    This paper proposes a reliability assessment method for thickness measurements of pipe wall using probability of detection (POD). Thicknesses of pipes are measured by qualified inspectors with ultrasonic thickness gauges. The inspection results are affected by human factors of the inspectors and include some errors, because the inspectors have different experiences and frequency of inspections. In order to ensure reliability for inspection results, first, POD evaluates experimental results of pipe-wall thickness inspection. We verify that the results have differences depending on inspectors including qualified inspectors. Second, two human factors that affect POD are indicated. Finally, it is confirmed that POD can identify the human factors and ensure reliability for pipe-wall thickness inspections. (author)

  14. OGLE-2012-bLG-0950Lb: the First Planet Mass Measurement From Only Microlens Parallax and Lens Flux

    Science.gov (United States)

    Koshimoto, N.; Udalski, A.; Beaulieu, J. P.; Sumi, T.; Bennett, D. P.; Bond, I. A.; Rattenbury, N.; Fukui, A.; Bhattacharya, A.; Suzuki, D.

    2016-01-01

    We report the discovery of a microlensing planet OGLE-2012-BLG-0950Lb with a planet/host mass ratio Periapsis Approx. = 2 x10(exp. -4). A long term distortion detected in both MOA and OGLE light curve can be explained by themicrolens parallax due to the Earths orbital motion around the Sun. Although the finite source effect is not detected, we obtain the lens flux by the high resolution Keck AO observation. Combining the microlens parallax and the lens flux reveal the nature of the lens: a planet with mass of M(sub p) = 35(+17/-)M compared to Earth is orbiting around an M-dwarf with mass of M(sub host) = 0.56(+0.12/-0.16) M compared to the Sun with a planet-host projected separation of r1 = 2.7(+0.6/-0.7) au located at Luminosity Distance = 3.0(+0.8/-1.1) kpc from us. This is the first mass measurement from only microlens parallax and the lens flux without the finite source effect. In the coming space observation-era with Spitzer, K2, Euclid, and WFIRST, we expect many such events for which we will not be able to measure any finite source effect. This work demonstrates an ability of mass measurements in such events.

  15. Measurements of attenuation coefficient for evaluating the hardness of a cataract lens by a high-frequency ultrasonic needle transducer

    Science.gov (United States)

    Chen, Ruimin; Tsui, Po-Hsiang; Zhou, Qifa; Humayun, Mark S; Shung, K Kirk

    2010-01-01

    A cataract is a clouding of the lens in the eye that affects vision. Phacoemulsification is the mostly common surgical method for treating cataracts, and determining that the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the use of an ultrasound needle transducer for invasive measurements of ultrasound attenuation coefficient to evaluate the hardness of the cataract lens. A 47 MHz high-frequency needle transducer with a diameter of 0.9 mm was fabricated by a polarized PMN-33%PT single crystal in the present study. The attenuation coefficients at different stages of an artificial porcine cataract lens were measured using the spectral shift approach. The hardness of the cataract lens was also evaluated by mechanical measurement of its elastic properties. The results demonstrated that the ultrasonic attenuation coefficient was increased from 0.048 ± 0.02 to 0.520 ± 0.06 dB mm−1 MHz−1 corresponding to an increase in Young’s modulus from 6 ± 0.4 to 96 ± 6.2 kPa as the cataract further developed. In order to evaluate the feasibility of combining needle transducer and phacoemulsification probe for real-time measurement during cataract surgery, the needle transducer was mounted on the phacoemulsification probe for a vibration test. The results indicated that there was no apparent damage to the tip of the needle transducer and the pulse–echo test showed that a good performance in sensitivity was maintained after the vibration test. PMID:19759408

  16. Measurements of attenuation coefficient for evaluating the hardness of a cataract lens by a high-frequency ultrasonic needle transducer

    International Nuclear Information System (INIS)

    Huang, C.-C.; Chen Ruimin; Zhou Qifa; Shung, K Kirk; Tsui, P.-H.; Humayun, Mark S

    2009-01-01

    A cataract is a clouding of the lens in the eye that affects vision. Phacoemulsification is the mostly common surgical method for treating cataracts, and determining that the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the use of an ultrasound needle transducer for invasive measurements of ultrasound attenuation coefficient to evaluate the hardness of the cataract lens. A 47 MHz high-frequency needle transducer with a diameter of 0.9 mm was fabricated by a polarized PMN-33%PT single crystal in the present study. The attenuation coefficients at different stages of an artificial porcine cataract lens were measured using the spectral shift approach. The hardness of the cataract lens was also evaluated by mechanical measurement of its elastic properties. The results demonstrated that the ultrasonic attenuation coefficient was increased from 0.048 ± 0.02 to 0.520 ± 0.06 dB mm -1 MHz -1 corresponding to an increase in Young's modulus from 6 ± 0.4 to 96 ± 6.2 kPa as the cataract further developed. In order to evaluate the feasibility of combining needle transducer and phacoemulsification probe for real-time measurement during cataract surgery, the needle transducer was mounted on the phacoemulsification probe for a vibration test. The results indicated that there was no apparent damage to the tip of the needle transducer and the pulse-echo test showed that a good performance in sensitivity was maintained after the vibration test.

  17. Measurement of facial soft tissues thickness using 3D computed tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ho Gul; Kim, Kee Deog; Shin, Dong Won; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Park, Chang Seo [Yonsei Univ. Hospital, Seoul (Korea, Republic of); Han, Seung Ho [Catholic Univ. of Korea, Seoul (Korea, Republic of)

    2006-03-15

    To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology.

  18. Measurement of facial soft tissues thickness using 3D computed tomographic images

    International Nuclear Information System (INIS)

    Jeong, Ho Gul; Kim, Kee Deog; Shin, Dong Won; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Park, Chang Seo; Han, Seung Ho

    2006-01-01

    To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology

  19. Measurement of abdominal muscle thickness using M-mode ultrasound imaging during functional activities.

    Science.gov (United States)

    Bunce, Steve M; Hough, Alan D; Moore, Ann P

    2004-02-01

    Ultrasound imaging has been previously utilized in the measurement of muscle thickness and cross-sectional area in research studies, and advocated as a clinical biofeedback tool in the rehabilitation of transversus abdominis function following episodes of low back pain. This paper describes how the thickness of the abdominal muscles can be quantified with a new measurement technique using M-mode ultrasound. The technique uses a custom-made transducer holder that facilitates measurement of muscle thickness changes during functional activity. Limitations of the technique and potential future applications are discussed. The M-mode ultrasound technique may provide an effective method for the non-invasive measurement of abdominal muscle thickness during functional activities.

  20. Quantitative CT measures of emphysema and airway wall thickness are related to D(L)CO

    DEFF Research Database (Denmark)

    Grydeland, Thomas B; Thorsen, Einar; Dirksen, Asger

    2011-01-01

    There is limited knowledge on the relationship between diffusing capacity of the lung for carbon monoxide (D(L)CO) and quantitative computed tomography (CT) measures of emphysema and airway wall thickness....

  1. LBA-ECO TG-03 Aeronet Aerosol Optical Thickness Measurements, Brazil: 1993-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes aerosol optical thickness measurements from the CIMEL sunphotometer for 22 sites in Brazil during the period from 1993-2005. The AERONET...

  2. LBA-ECO TG-03 Aeronet Aerosol Optical Thickness Measurements, Brazil: 1993-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set includes aerosol optical thickness measurements from the CIMEL sunphotometer for 22 sites in Brazil during the period from 1993-2005. The...

  3. Auto-synchronized laser scanning range sensor for thermoplastic pavement marking material thickness measurement

    Science.gov (United States)

    Sun, Wei; Chen, Xuemin; Chen, Yuanhang; Ekbote, Aditya; Liu, Richard Ce

    2006-03-01

    Pavement marking materials provide delineation on highways around the world. The condition of the marking materials is very important for the driver's safety as well as the comfort and the driving expenses. Currently thermoplastic pavement marking materials (TPMM) are widely used in states. Measuring the thickness of TPMM on pavement is an essential index to monitor the contractors, calculate durability of marking materials, and provide better information for the pavement marking evaluation. In recent years to measure the thickness of TPMM, a procedure involving pre-embedded plates sprayed with the marking materials has been widely accepted. This method is labor intensive, and cannot obtain a continuous-thickness profile. Therefore there are demands to develop a high-speed automatic measuring system for determining the thickness and uniformity of marking materials. In this paper, a laser range sensor based on auto-synchronized laser scanning is proposed for the thermoplastic pavement marking material thickness measurement. Compare to classical triangulation method, this approach doesn't scarify the system resolution for large field of view and it is more suitable for highway speed measurement. To achieve high speed measurement, PSD (Position Sensitive Detector) is used in the prototype system instead of CCD (Charge Couple Device) in traditional auto-synchronized system. The standoff distance and transverse scan range of the prototype system both are 1 foot. The lab test results show that the prototype system can measure the thermoplastic type thickness with error in 5mil at laser scanning rate up to 50Hz.

  4. Quantitative CT measures of emphysema and airway wall thickness are related to D(L)CO

    DEFF Research Database (Denmark)

    Grydeland, Thomas B; Thorsen, Einar; Dirksen, Asger

    2011-01-01

    There is limited knowledge on the relationship between diffusing capacity of the lung for carbon monoxide (D(L)CO) and quantitative computed tomography (CT) measures of emphysema and airway wall thickness.......There is limited knowledge on the relationship between diffusing capacity of the lung for carbon monoxide (D(L)CO) and quantitative computed tomography (CT) measures of emphysema and airway wall thickness....

  5. Perirenal fat thickness measured with computed tomography is a reliable estimate of perirenal fat mass.

    Directory of Open Access Journals (Sweden)

    Guillaume Favre

    Full Text Available Deposition of perirenal adipose tissue has been associated with adverse renal and cardiovascular events. We compared various methods to measure perirenal adipose tissue using computerized tomography (CT-scan and performed correlations with anthropometric measures associated with renal and cardiovascular events. Voluntary overweight and obese subjects undergoing a CT-scan for diagnostic purposes were included in the study. Perirenal adipose tissue volume, adipose tissue area of the renal sinus and perirenal fat thickness were manually measured bilaterally. The intra- and inter-observer coefficient correlations and the correlation between the diverse measures of renal adipose tissue, subcutaneous (SC-fat and anthropometrics measures were analyzed using Pearson's correlation tests. The forty included patients (24 men, 16 women had a mean age of 57.6 ± 18.1 years and a mean body mass index of 28.9 ± 2.9 kg/m2. Despite comparable waist circumference, women had a greater SC-fat thickness compared to men, and therefore a smaller amount of visceral fat, as well as smaller perirenal fat volumes. Perirenal fat thickness was better correlated with perirenal fat volume than adipose area of the renal sinus (p <0.02. The adipose area of the renal sinus did not correlate with any anthropometric measures. In women, perirenal fat volume and thickness showed a negative correlation with SC-fat thickness and no correlation with waist circumference. In men, perirenal fat volume and thickness showed a positive correlation with waist circumference and no correlation with subcutaneous fat thickness. In conclusion, perirenal fat thickness measured with CT-scan at the level of the renal veins is a simple and reliable estimate of perirenal fat volume, that correlated negatively with SC-fat in women and positively with waist circumference in men. The adipose area of the renal sinus did not correlate with any anthropometric measure.

  6. The influence of product thickness on the measurements by Barkhausen Noise method

    OpenAIRE

    T. Garstka

    2008-01-01

    Purpose: The aim of this paper is to show how varying cross section thickness of tested product and calibration sample can depend on results of the residual stress measurements by the Barkhausen Noise method.Design/methodology/approach: The Barkhausen noise parameters as RMS value and total number of Barkhausen pulses in samples with different thickness was measured and compared. Also influence of the frequency and intensity of the magnetization current was analysing.Findings: The significant...

  7. Double-beam optical method and apparatus for measuring thermal diffusivity and other molecular dynamic processes in utilizing the transient thermal lens effect

    International Nuclear Information System (INIS)

    Gupta, A.; Hong, S.; Moacanin, J.

    1981-01-01

    A method and apparatus for measuring thermal diffusivity and molecular relaxation processes in a sample material utilizing two light beams, one being a pulsed laser light beam for forming a thermal lens in the sample material, and the other being a relatively low power probe light beam for measuring changes in the refractive index of the sample material during formation and dissipation of the thermal lens. More specifically, a sample material is irradiated by relatively high power, short pulses from a dye laser. Energy from the pulses is absorbed by the sample material, thereby forming a thermal lens in the area of absorption. The pulse repetition rate is chosen so that the thermal lens is substantially dissipated by the time the next pulse reaches the sample material. A probe light beam, which in a specific embodiment is a relatively low power, continuous wave (Cw) laser beam, irradiates the thermal lens formed in the sample material. The intensity characteristics of the probe light beam subsequent to irradiation of the thermal lens is related to changes in the refractive index of the sample material as the thermal lens is formed and dissipated. A plot of the changes in refractive index as a function of time during formation of the thermal lens as reflected by changes in intensity of the probe beam, provides a curve related to molecular relaxation characteristics of the material, and a plot during dissipation of the thermal lens provides a curve related to the thermal diffusivity of the sample material

  8. Measurement of sea ice thickness using electromagnetic sounding; Denji tansaho wo mochiita kaihyoatsu no keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Kawauchi, K.; Suzuki, I.; Goto, N. [Muroran Institute of Technology, Hokkaido (Japan); Hoshiyama, K.

    1997-10-22

    Thickness of sea ice is measured by an electromagnetic method making use of the peculiarities of sea ice. Sea ice floats on the seawater (saline water), and the result is two horizontal layers greatly different from each other in conductivity, with seawater being highly conductive and ice being non-conductive. A study is conducted on Lake Kumatori, a saline lake in Abashiri City, in which effort a board of naturally frozen sea ice and a board of sea ice allowed to form on the sea surface at a spot from which ice has been removed are examined. A portable electromagnetic probe EM38 of GEONICS Company is employed to perform measurement in a horizontal dipole mode. To determine the relationship between the obtained conductivity measurements and sea ice thickness, holes are bored in the sea ice boards for the measurement of their thickness for the formulation of an experimental regression equation. Measurements along the traverse line 1 and traverse line 3 are converted into sea ice thickness by use of the experimental regression equation, and the result is that ice thickness is the greatest near the quay growing thinner away from the shore. The study shows that sea ice thickness may be measured accurately by electromagnetic probing. 3 refs., 10 figs.

  9. Axial-scanning low-coherence interferometer method for noncontact thickness measurement of biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do-Hyun; Song, Chul-Gyu; Ilev, Ilko K.; Kang, Jin U.

    2011-02-20

    We investigated a high-precision optical method for measuring the thickness of biological samples regardless of their transparency. The method is based on the precise measurement of optical path length difference of the end surfaces of objects, using a dual-arm axial-scanning low-coherence interferometer. This removes any consideration of the shape, thickness, or transparency of testing objects when performing the measurement. Scanning the reference simplifies the measurement setup, resulting in unambiguous measurement. Using a 1310 nm wavelength superluminescent diode, with a 65 nm bandwidth, the measurement accuracy was as high as 11.6 {mu}m. We tested the method by measuring the thickness of both transparent samples and nontransparent soft biological tissues.

  10. Perirenal fat thickness measured with computed tomography is a reliable estimate of perirenal fat mass.

    Science.gov (United States)

    Favre, Guillaume; Grangeon-Chapon, Caroline; Raffaelli, Charles; François-Chalmin, Florence; Iannelli, Antonio; Esnault, Vincent

    2017-01-01

    Deposition of perirenal adipose tissue has been associated with adverse renal and cardiovascular events. We compared various methods to measure perirenal adipose tissue using computerized tomography (CT)-scan and performed correlations with anthropometric measures associated with renal and cardiovascular events. Voluntary overweight and obese subjects undergoing a CT-scan for diagnostic purposes were included in the study. Perirenal adipose tissue volume, adipose tissue area of the renal sinus and perirenal fat thickness were manually measured bilaterally. The intra- and inter-observer coefficient correlations and the correlation between the diverse measures of renal adipose tissue, subcutaneous (SC-)fat and anthropometrics measures were analyzed using Pearson's correlation tests. The forty included patients (24 men, 16 women) had a mean age of 57.6 ± 18.1 years and a mean body mass index of 28.9 ± 2.9 kg/m2. Despite comparable waist circumference, women had a greater SC-fat thickness compared to men, and therefore a smaller amount of visceral fat, as well as smaller perirenal fat volumes. Perirenal fat thickness was better correlated with perirenal fat volume than adipose area of the renal sinus (p perirenal fat volume and thickness showed a negative correlation with SC-fat thickness and no correlation with waist circumference. In men, perirenal fat volume and thickness showed a positive correlation with waist circumference and no correlation with subcutaneous fat thickness. In conclusion, perirenal fat thickness measured with CT-scan at the level of the renal veins is a simple and reliable estimate of perirenal fat volume, that correlated negatively with SC-fat in women and positively with waist circumference in men. The adipose area of the renal sinus did not correlate with any anthropometric measure.

  11. Application of a virtual coordinate measuring machine for measurement uncertainty estimation of aspherical lens parameters

    International Nuclear Information System (INIS)

    Küng, Alain; Meli, Felix; Nicolet, Anaïs; Thalmann, Rudolf

    2014-01-01

    Tactile ultra-precise coordinate measuring machines (CMMs) are very attractive for accurately measuring optical components with high slopes, such as aspheres. The METAS µ-CMM, which exhibits a single point measurement repeatability of a few nanometres, is routinely used for measurement services of microparts, including optical lenses. However, estimating the measurement uncertainty is very demanding. Because of the many combined influencing factors, an analytic determination of the uncertainty of parameters that are obtained by numerical fitting of the measured surface points is almost impossible. The application of numerical simulation (Monte Carlo methods) using a parametric fitting algorithm coupled with a virtual CMM based on a realistic model of the machine errors offers an ideal solution to this complex problem: to each measurement data point, a simulated measurement variation calculated from the numerical model of the METAS µ-CMM is added. Repeated several hundred times, these virtual measurements deliver the statistical data for calculating the probability density function, and thus the measurement uncertainty for each parameter. Additionally, the eventual cross-correlation between parameters can be analyzed. This method can be applied for the calibration and uncertainty estimation of any parameter of the equation representing a geometric element. In this article, we present the numerical simulation model of the METAS µ-CMM and the application of a Monte Carlo method for the uncertainty estimation of measured asphere parameters. (paper)

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

    Science.gov (United States)

    Larimer, Curtis; Suter, Jonathan D; Bonheyo, George; Addleman, Raymond Shane

    2016-06-01

    Biofilms are ubiquitous and impact the environment, human health, dental hygiene, and a wide range of industrial processes. Biofilms are difficult to characterize when fully hydrated, especially in a non-destructive manner, because of their soft structure and water-like bulk properties. Herein a method of measuring and monitoring the thickness and topology of live biofilms of using white light interferometry is described. Using this technique, surface morphology, surface roughness, and biofilm thickness were measured over time without while the biofilm continued to grow. The thickness and surface topology of a P. putida biofilm were monitored growing from initial colonization to a mature biofilm. Measured thickness followed expected trends for bacterial growth. Surface roughness also increased over time and was a leading indicator of biofilm growth. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Macular thickness and macular volume measurements using spectral domain optical coherence tomography in normal Nepalese eyes

    Directory of Open Access Journals (Sweden)

    Pokharel A

    2016-03-01

    Full Text Available Amrit Pokharel,1 Gauri Shankar Shrestha,2 Jyoti Baba Shrestha2 1Department of Ophthalmology, Kathmandu Medical College Teaching Hospital, 2B P Koirala Lions Centre for Ophthalmic Studies, Institute of Medicine, Kathmandu, Nepal 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. Keywords: macular thickness, macular volume, optical coherence tomography, Nepal

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

    Science.gov (United States)

    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.

  15. An evaluation of dental radiograph accuracy in the measurement of enamel thickness.

    Science.gov (United States)

    Grine, F E; Stevens, N J; Jungers, W L

    2001-12-01

    Many studies have employed lateral radiographs to measure the thickness of tooth enamel in recent human and fossil hominid samples, but the accuracy of measurements obtained by this technique has not been assessed. In this study, 20 isolated human maxillary permanent molars were radiographed using the parallel film technique. The crowns were then sectioned longitudinally through the tips of the buccal cusps. Measurements of enamel cap area, and of linear enamel thickness in the occlusal basin and over the metacone apex, were made from the radiographs and corresponding sectioned surfaces. Comparisons of the two sets of values revealed that radiographs generally overestimated enamel thickness but there was considerable variability in the error by which measurements from radiographs either under- or overestimated the true value. Lateral radiographs may provide a rough visual impression of whether a tooth has thin or thick enamel but they do not generally provide for accurate measurement of enamel thickness. Quantitative data on enamel thickness from studies that have employed lateral radiographs should be viewed with circumspection.

  16. Type testing of a head band dosemeter for measuring eye lens dose in terms of H(P)(3).

    Science.gov (United States)

    Gilvin, P J; Baker, S T; Gibbens, N J; Roberts, G H; Tanner, R J; Eakins, J S; Hager, L G; Daniels, T J

    2013-12-01

    A new head band dosemeter, for the measurement of eye lens dose in terms of Hp(3), has been type tested by Public Health England's Centre for Radiation, Environmental and Chemical Hazards [formerly part of the UK Health Protection Agency (HPA)]. The type tests were based on the International Standard ISO 12794, drawing also upon earlier work at HPA. The results show that, unlike many existing dosemeters, the new head band dosemeter correctly measures Hp(3) for beta radiations as well as photons.

  17. Analysis and Comparison of Thickness and Bending Measurements from Fabric Touch Tester (FTT and Standard Methods

    Directory of Open Access Journals (Sweden)

    Musa Atiyyah Binti Haji

    2018-03-01

    Full Text Available Fabric Touch Tester (FTT is a relatively new device from SDL Atlas to determine touch properties of fabrics. It simultaneously measures 13 touch-related fabric physical properties in four modules that include bending and thickness measurements. This study aims to comparatively analyze the thickness and bending measurements made by the FTT and the common standard methods used in the textile industry. The results obtained with the FTT for 11 different fabrics were compared with that of standard methods. Despite the different measurement principle, a good correlation was found between the two methods used for the assessment of thickness and bending. As FTT is a new tool for textile comfort measurement and no standard yet exists, these findings are essential to determine the reliability of the measurements and how they relate to the well-established standard methods.

  18. Ultrasonographic measurement of the axillary recess thickness in an asymptomatic shoulder

    Directory of Open Access Journals (Sweden)

    Gi-Young Park

    2017-04-01

    Full Text Available 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.

  19. Ultrasonographic measurement of the axillary recess thickness in an asymptomatic shoulder

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gi Young; Lee, Jin Hoon; Kwon, Dae Gil [Dept. of Rehabilitation Medicine, Catholic University of Daegu School of Medicine, Daegu (Korea, Republic of)

    2017-04-15

    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. 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. 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). 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.

  20. Assessment of the accuracy of dental enamel thickness measurements using microfocal X-ray computed tomography.

    Science.gov (United States)

    Olejniczak, Anthony J; Grine, Frederick E

    2006-03-01

    Tooth enamel thickness has long been an important character in studies of primate and especially hominin phylogeny, taxonomy, and adaptation. Current methods for accurately assessing enamel thickness involve the physical sectioning of teeth, because measurements of enamel thickness using some radiographic techniques are unreliable. However, because destructive methods limit sample sizes and access to important fossil specimens, it is desirable that they be replaced with nondestructive techniques. Although microfocal X-ray computed tomography (mCT) has been used recently in studies of enamel thickness, the accuracy of this technique has yet to be established. The present research compares physical sections to computer-generated mCT sections of teeth from a variety of primate and nonprimate, recent and fossil taxa to examine whether enamel thickness, tooth size, and diagenetic remineralization (fossilization) impact the ability of mCT to measure enamel thickness accurately. Results indicate that recent teeth of varying size and thickness are clearly and accurately depicted in mCT scans, with measurements from nearly identical planes in physical and mCT sections differing by 3-5%. A fossil papionin molar (ca. 2 Myr) was also accurately measured using mCT scans, although thinner enamel in much older therapsid (ca. 263-241 Myr) teeth could not be distinguished from dentine. mCT is thus an accurate technique for measuring enamel thickness in recent taxa, although heavily mineralized teeth pose an obstacle to the ability of mCT to distinguish dental tissues. Moreover, absolutely thin enamel (less than approximately 0.10 mm) is difficult to resolve adequately in raw mCT images based on pixel values alone. Therefore, caution must be exercised in the application of mCT to the study of fossilized teeth.

  1. Measurement and clinical implications of choroidal thickness in patients with inflammatory bowel disease

    Directory of Open Access Journals (Sweden)

    Ibrahim Koral Onal

    2015-10-01

    Full Text Available ABSTRACTPurpose:Ocular inflammation is a frequent extraintestinal manifestation of inflammatory bowel disease (IBD and may parallel disease activity. In this study, we evaluated the utility of a choroidal thickness measurement in assessing IBD activity.Methods:A total of 62 eyes of 31 patients with IBD [Crohn's disease (CD, n=10 and ulcerative colitis (UC, n=21] and 104 eyes of 52 healthy blood donors were included in this study. Choroidal thickness was measured using enhanced depth imaging optical coherence tomography. The Crohn's disease activity index (CDAI and the modified Truelove Witts score were used to assess disease activity in CD and UC, respectively.Results:No significant differences in mean subfoveal, nasal 3000 μm, or temporal 3000 μm choroidal thickness measurements (P>0.05 for all were observed between IBD patients and healthy controls. Age, smoking, CD site of involvement (ileal and ileocolonic involvement, CDAI, CD activity, and UC endoscopic activity index were all found to be significantly correlated with choroidal thickness by univariate analysis (P<0.05. Smoking (P<0.05 and the CD site of involvement (P<0.01 were the only independent parameters associated with increased choroidal thickness at all measurement locations.Conclusions:Choroidal thickness is not a useful marker of disease activity in patients with IBD but may be an indicator of ileal involvement in patients with CD.

  2. Error Analysis of Ceramographic Sample Preparation for Coating Thickness Measurement of Coated Fuel Particles

    International Nuclear Information System (INIS)

    Liu Xiaoxue; Li Ziqiang; Zhao Hongsheng; Zhang Kaihong; Tang Chunhe

    2014-01-01

    The thicknesses of four coatings of HTR coated fuel particle are very important parameters. It is indispensable to control the thickness of four coatings of coated fuel particles for the safety of HTR. A measurement method, ceramographic sample-microanalysis method, to analyze the thickness of coatings was developed. During the process of ceramographic sample-microanalysis, there are two main errors, including ceramographic sample preparation error and thickness measurement error. With the development of microscopic techniques, thickness measurement error can be easily controlled to meet the design requirements. While, due to the coated particles are spherical particles of different diameters ranged from 850 to 1000μm, the sample preparation process will introduce an error. And this error is different from one sample to another. It’s also different from one particle to another in the same sample. In this article, the error of the ceramographic sample preparation was calculated and analyzed. Results show that the error introduced by sample preparation is minor. The minor error of sample preparation guarantees the high accuracy of the mentioned method, which indicates this method is a proper method to measure the thickness of four coatings of coated particles. (author)

  3. Refractive index and geometrical thickness measurement of a transparent pellicle in air by Gaussian beam defocusing.

    Science.gov (United States)

    Olvera-R, Octavio; Cywiak, Moisés; Cervantes-L, Joel; Morales, Arquímedes

    2014-04-10

    We demonstrate that it is possible to measure the local geometrical thickness and the refractive index of a transparent pellicle in air by combining the diffractive properties of a Gaussian beam with the analytical equations of the light that propagates through a thin layer. We show that our measurement technique is immune to inherent piston-like vibrations present in the pellicle. As our measurements are based on characterizing properly the Gaussian beam in a plane of detection, a homodyne technique for this purpose is devised and described. The feasibility of our proposal is confirmed by measuring local geometrical thicknesses and the refractive index of a commercially available stretch film.

  4. A new approach to alloy compensation in a thickness measurement of high-tensile steel

    International Nuclear Information System (INIS)

    Lee, Jin Woo; Lee, Yun Jong; Kim, Chan Hyeong; Choi, Cheol Hee

    2013-06-01

    In on-line manufacturing iron-making process, several kinds of element are mixed in iron in order to meet the required quality for a final product. In this paper, the results show that the alloy compensation method is needed to improve accuracy required at thickness gauge, that is, ±0.5% at the target thickness. In addition, the alloy compensation method in measurement will be proposed in the form of correction function of each element weight percentage to be alloyed using the analyzed result of MCNP simulation program. Finally, an automatic thickness compensation method applied to the high-tensile steel product during manufacturing is introduced. (authors)

  5. Method of accurate thickness measurement of boron carbide coating on copper foil

    Science.gov (United States)

    Lacy, Jeffrey L.; Regmi, Murari

    2017-11-07

    A method is disclosed of measuring the thickness of a thin coating on a substrate comprising dissolving the coating and substrate in a reagent and using the post-dissolution concentration of the coating in the reagent to calculate an effective thickness of the coating. The preferred method includes measuring non-conducting films on flexible and rough substrates, but other kinds of thin films can be measure by matching a reliable film-substrate dissolution technique. One preferred method includes determining the thickness of Boron Carbide films deposited on copper foil. The preferred method uses a standard technique known as inductively coupled plasma optical emission spectroscopy (ICPOES) to measure boron concentration in a liquid sample prepared by dissolving boron carbide films and the Copper substrates, preferably using a chemical etch known as ceric ammonium nitrate (CAN). Measured boron concentration values can then be calculated.

  6. Normal bladder wall thickness measurement in healthy Iranian children, a cross-sectional study

    OpenAIRE

    Adibi, Atoosa; Kazemian, Afarin; Toghiani, Ali

    2014-01-01

    Background: Normal bladder function is necessary for micturition. Many causes such as urinary tract infection, bladder outlet obstruction, and neuropathic bladder can influence bladder wall thickness (BWT).This study was designed to determine normal BWT in Iranian children. Materials and Methods: This was a cross-sectional study done in Isfahan in 2012 comprising 82 children aged 2-14 years without any urinary complaint. We measured thickness of posterior and lateral walls of the bladder ...

  7. Characterization of the flooding in vertical tubes by means of the film thickness measurement

    International Nuclear Information System (INIS)

    Malandrone, M.; Mioliggi, L.; Panella, B.; Scorta, G.

    1992-01-01

    The air-water countercurrent flow up to the flooding transition in a vertical tube has been experimentally investigated by liquid film thickness measurement performed by means of an electrical two-wires conductance probe. The liquid film mean thickness, the probability density function, the spectral power density and the power of the signal have been derived for a wide range of air and water flow rate, and related to the flow pattern with particular attention to the flooding phenomena. (6 figures) (Author)

  8. Measurement of Mucosal Thickness in Denture-bearing Area of Edentulous Mandible

    Directory of Open Access Journals (Sweden)

    Jian Dong

    2015-01-01

    Full Text Available Background: The thickness of the alveolar mucosa influences the probability of the occurrence of denture-induced irritations. Thick denture-supporting tissues offer relief from mucosal tenderness and ulcers; however, the uniformity of the thickness across the entire mandibular alveolar mucosa cannot be accurately determined in edentulous patients. This study aimed to assess the mucosal thickness of the denture-bearing area in the edentulous mandible. Methods: Twenty-seven edentulous patients underwent cone-beam computed tomography scanning, wherein the patients wore a record base to retract soft tissues away from the alveolar mucosa. The measured regions were the central incisor (IC, lateral incisor (IL, canine (Ca, first premolar (P1, second premolar (P2, first molar (M1, and second molar (M2 regions. The thickness was measured in the alveolar ridge crest (T, buccal (B1-B4, and lingual (L1-L4 alveolar ridge mucosa. The average thickness of the mucosa at buccal sides (B and lingual sides (L were also assessed. Results: The differences in the mucosal thickness between the left and right sides were not significant. In the Ca-M2 regions, T was the thickest, and L3 was the thinnest of all the measured points in the same regions. L was significantly less than B in posterior regions (P < 0.01. On the other hand, M2 at L4 was thinnest of all the measured regions from Ca to M2 (P < 0.01, and was thicker than IC, IL, P1, and P2 at B2. Conclusions: Since the mucosal thickness of denture-bearing area in the edentulous mandible is not uniform; the tissue surface of the denture base or custom tray should be selectively relieved, which may reduce the risk of denture-induced irritations.

  9. Measurements of Corneal Thickness in Eyes with Pseudoexfoliation Syndrome: Comparative Study of Different Image Processing Protocols

    Directory of Open Access Journals (Sweden)

    Katarzyna Krysik

    2017-01-01

    Full Text Available Purpose. Comparative analysis of central and peripheral corneal thickness in PEX patients using three different imaging systems: Pentacam-Scheimpflug device, time-domain optical coherence tomography (OCT Visante, and swept-source OCT Casia. Materials and Methods. 128 eyes of 80 patients with diagnosed PEX were examined and compared with 112 normal, non-PEX eyes of 72 cataract patients. The study parameters included 5 measured zones: central and 4 peripheral (superior, inferior, nasal, and temporal. Results. The mean CCT in eyes with PEX syndrome measured with all three instruments was thicker than that in normal eyes. Corneal thickness measurements in the PEX group were statistically significantly different between Pentacam and OCT Casia: central corneal thickness (p=0.04, inferior corneal zone (p=0.01, and nasal and temporal corneal zones (p<0.01. Between Pentacam and OCT Visante inferior, nasal and temporal corneal zones were statistically significantly different (p<0.01. Between OCT Casia and OCT Visante, there were no statistically significant differences in measured parameters values. Conclusion. The central corneal thickness in eyes with PEX syndrome measured with three different independent methods is higher than that in the non-PEX group, and despite variable peripheral corneal thickness, this one parameter is still crucial in intraocular pressure measurements.

  10. Ultrasound measures of supraspinatus tendon thickness and acromiohumeral distance in rotator cuff tendinopathy are reliable.

    Science.gov (United States)

    McCreesh, Karen M; Anjum, Shakeel; Crotty, James M; Lewis, Jeremy S

    2016-01-01

    Rotator cuff (RC) tendinopathy has been widely ascribed to impingement of the supraspinatus tendon (SsT) in the subacromial space, measured as the acromiohumeral distance (AHD). Ultrasound (US) is suitable for measuring AHD and SsT thickness, but few reliability studies have been carried out in symptomatic populations, and interrater reliability is unconfirmed. This study aimed to examine the intrarater and interrater reliability of US measurements of AHD and SsT thickness in asymptomatic control subjects and patients with RC tendinopathy. Seventy participants were recruited and grouped as healthy controls (n = 25) and RC tendinopathy (n = 45). Repeated US measurements of AHD and SsT thickness were obtained by one rater in both groups and by two raters in the RC tendinopathy group. Intrarater and interrater reliability coefficients were excellent for both measurements (intraclass correlation > 0.92), but the intrarater reliability was superior. The minimal detectable change values in the symptomatic group were 0.7 mm for AHD and 0.6 mm for SsT thickness for a single experienced examiner; the values rose to 1.2 mm and 1.3 mm, respectively, for the pair of examiners. The results support the reliability of US for the measurement of AHD and SsT thickness in patients with symptomatic RC tendinopathy and provide minimal detectable change values for use in future research studies. © 2015 Wiley Periodicals, Inc.

  11. Basic concepts of optical measuring of bone thickness with IR-beam.

    Science.gov (United States)

    Wolff, Regine; Deppe, Herbert; Lueth, Tim C

    2011-01-01

    This paper describes a new concept for measuring bone thickness via optically analyzing of hard tissue. In many surgical disciplines effecting bone treatment, like oral and maxillofacial surgery or otolaryngology, the knowledge of existing bone material is very important in order not to hurt anatomically sensitive structures. The existing bone material can be determined preoperatively using imaging procedures. However, the surgeon has no information about the residual bone thickness during the intervention. As a consequence of this, the distance between the tip of his instrument and sensitive structures is also unknown. Therefore, it would be very useful, if the bone thickness could be measured concurrently to the bone ablation. In this work, bone was irradiated with IR-Light and the reflection was detected. It would be examined, if there was an interrelation between bone thickness and reflection and how it could be measured. The results of the experiments show, that by means of this method it is possible to detect different bone thicknesses for a bone thickness < 1 mm.

  12. Measurements of tunneling barrier thicknesses for Nb/Al–AlOx/Nb tunnel junctions

    International Nuclear Information System (INIS)

    Kang, Xinjie; Ying, Liliang; Wang, Hai; Zhang, Guofeng; Peng, Wei; Kong, Xiangyan; Xie, Xiaoming; Wang, Zhen

    2014-01-01

    Highlights: • We estimate the average barrier height (Φ) of Nb/Al–AlO x /Nb tunnel junctions. • Dependence of the AlOx thickness (dAlOx) on O 2 exposure was described. • The thicknesses of AlOx barriers were measured using transmission electron microscopy (TEM). • X-ray Reflection (XRR) measurements and simulations were used to verify the AlOx thickness. - Abstract: The tunnel barrier thicknesses of Nb/Al–AlO x /Nb tunnel junctions were measured using transmission electron microscopy (TEM) and X-ray Reflection (XRR). By investigating the barrier thickness dependence of current density J c , the barrier height for Nb/Al–AlO x /Nb junctions was calculated. Nb/Al–AlO x /Nb junctions with different J c were fabricated by controlling the O 2 exposure in Al oxidation. The junctions show good tunneling properties with subgap leakage factor V m larger than 30 mV in the range of J c from tens of A/cm 2 to several kA/cm 2 . TEM images showed clear interface and indicated the AlO x thicknesses ranging from 0.8 nm to 1.9 nm, and the average barrier height was estimated to be 0.17 eV for Nb/Al–AlO x /Nb tunnel junctions

  13. Muscle thickness measurements to estimate gluteus medius and minimus activity levels.

    Science.gov (United States)

    Dieterich, Angela V; Pickard, Christine M; Strauss, Geoffrey R; Deshon, Louise E; Gibson, William; McKay, Janice

    2014-10-01

    The clinical assessment of gluteus medius and minimus force sharing requires non-invasive measurements of individual activity levels. Do ultrasound measurements of change of muscle thickness substitute invasive electromyography (EMG)? Isometric hip abduction in 20-80% maximal voluntary isometric contraction (MVIC) was measured using dynamometry, M-mode ultrasound for gluteus medius and minimus thickness and EMG using (1) surface electrodes on gluteus medius, n = 15, (2) fine-wire electrodes in deep gluteus medius and minimus, n = 6. Gluteus medius thickened by 5.0 (SD 2.5) mm at 80% MVIC while gluteus minimus thickness was constant in the surface EMG study and decreased by 1.6 (SD 1.6) mm at the more ventral location in the fine-wire EMG study. Thickness change of gluteus medius enabled prediction of torque (r(2) 0.66) and of surface EMG amplitude (r(2) 0.57). Surface EMG enabled higher torque prediction (r(2) 0.84) than thickness change. Thickness change of gluteus minimus did not enable a practically relevant estimation of torque production. Ultrasound examination revealed a differential thickening behaviour of gluteus medius and minimus which enabled estimation of isometric torque production only for gluteus medius but with lower precision than surface EMG. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Interferometric And Microscopic Measurements Of Surface Finish Appearance Evaluations Of Ophthalmic Lens Edges

    Science.gov (United States)

    Gamble, M.; Mezghani, S.; El Mansori, M.; Divo, F.

    2011-01-01

    Surface appearance and product material integrity are important features that will affect product functionality, reliability and customer confidence. Yet despite this, and perhaps surprisingly, lens surface inspection is still undertaken visually with undefined criteria, varying levels of quality expertise, and differing moods of inspectors. In this paper, an objective quality inspection method for the polished edge of ophthalmic lenses is developed. Four defect categorizes have been indentified on the machined edge of non-acceptable lenses: chatter marks, linear, creep and cracks. Chatter matters have an irregular surface with waviness. The linear defect has a linear defect along the lens' edge surface. Creep has deformation of the surface due to the material removal process. Cracks have cracks along the surface of the lens. The developed technique was applied to several ophthalmic lens materials (Polycarbonate, CR39, high index materials) that contain defects of diverse shapes and sizes in different locations. Results show the effectiveness of the developed inspection technique for ophthalmic lens quality assurance and defect identification. It was also found that there is a correlation between the scale-sensitive fractal dimension parameter and surface finish appearance.

  15. Direct phase-shift measurement of an EUV mask with gradient absorber thickness

    Science.gov (United States)

    Tanabe, Hiroyoshi; Murachi, Tetsunori; Park, Seh-Jin; Gullikson, Eric M.; Abe, Tsukasa; Hayashi, Naoya

    2013-09-01

    We directly extracted the phase-shift values of an EUV mask by measuring the reflectance of the mask. The mask had gradient absorber thickness along vertical direction. We measured the reflectance of the open multilayer areas and the absorber areas by using an EUV reflectometer at various absorber thicknesses. We also measured the diffracted 0th order light intensities of grating patterns having several sizes of lines or holes. The phase-shift values were derived from these data assuming a flat mask interference model of the diffracted lights. This model was corrected by including the scattering amplitude from the pattern edges. We recalculated the phase-shift values which was free from the mask topological effect. The extracted phase-shift value was close to 180 degrees at 67 nm and 71 nm absorber thicknesses. The phase measurement error around 180 degree phase shift was 5 degrees (3σ).

  16. Thickness measurement by two-sided step-heating thermal imaging

    Science.gov (United States)

    Li, Xiaoli; Tao, Ning; Sun, J. G.; Zhang, Cunlin; Zhao, Yuejin

    2018-01-01

    Infrared thermal imaging is a promising nondestructive technique for thickness prediction. However, it is usually thought to be only appropriate for testing the thickness of thin objects or near-surface structures. In this study, we present a new two-sided step-heating thermal imaging method which employed a low-cost portable halogen lamp as the heating source and verified it with two stainless steel step wedges with thicknesses ranging from 5 mm to 24 mm. We first derived the one-dimensional step-heating thermography theory with the consideration of warm-up time of the lamp, and then applied the nonlinear regression method to fit the experimental data by the derived function to determine the thickness. After evaluating the reliability and accuracy of the experimental results, we concluded that this method is capable of testing thick objects. In addition, we provided the criterions for both the required data length and the applicable thickness range of the testing material. It is evident that this method will broaden the thermal imaging application for thickness measurement.

  17. TWO STARS TWO WAYS: CONFIRMING A MICROLENSING BINARY LENS SOLUTION WITH A SPECTROSCOPIC MEASUREMENT OF THE ORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Jennifer C.; Johnson, John Asher; Eastman, Jason; Vanderburg, Andrew [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Skowron, Jan [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, Andrew [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Pineda, J. Sebastian [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Howard, Andrew, E-mail: jyee@cfa.harvard.edu, E-mail: jjohnson@cfa.harvard.edu, E-mail: jason.eastman@cfa.harvard.edu, E-mail: avanderburg@cfa.harvard.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States)

    2016-04-20

    Light curves of microlensing events involving stellar binaries and planetary systems can provide information about the orbital elements of the system due to orbital modulations of the caustic structure. Accurately measuring the orbit in either the stellar or planetary case requires detailed modeling of subtle deviations in the light curve. At the same time, the natural, Cartesian parameterization of a microlensing binary is partially degenerate with the microlens parallax. Hence, it is desirable to perform independent tests of the predictions of microlens orbit models using radial velocity (RV) time series of the lens binary system. To this end, we present 3.5 years of RV monitoring of the binary lens system OGLE-2009-BLG-020 L, for which Skowron et al. constrained all internal parameters of the 200–700 day orbit. Our RV measurements reveal an orbit that is consistent with the predictions of the microlens light curve analysis, thereby providing the first confirmation of orbital elements inferred from microlensing events.

  18. Measurement of lateral charge diffusion in thick, fully depleted, back-illuminated CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Karcher, Armin; Bebek, Christopher J.; Kolbe, William F.; Maurath, Dominic; Prasad, Valmiki; Uslenghi, Michela; Wagner, Martin

    2004-06-30

    Lateral charge diffusion in back-illuminated CCDs directly affects the point spread function (PSF) and spatial resolution of an imaging device. This can be of particular concern in thick, back-illuminated CCDs. We describe a technique of measuring this diffusion and present PSF measurements for an 800 x 1100, 15 mu m pixel, 280 mu m thick, back-illuminated, p-channel CCD that can be over-depleted. The PSF is measured over a wavelength range of 450 nm to 650 nm and at substrate bias voltages between 6 V and 80 V.

  19. Ultrasonic measurement of enamel thickness : a tool for monitoring dental erosion?

    NARCIS (Netherlands)

    Huysmans, MCDNJM; Thijssen, JM

    Objectives: Wear of dental hard tissues, e.g. dental erosion, is reported to be a growing problem. A non-destructive measurement of enamel layer thickness would provide the opportunity for both early diagnosis, and longitudinal measurement of progressive enamel loss. It was the aim of this study to

  20. A NEW METHOD FOR MEASURING NEUTRON-SKIN THICKNESS IN RARE ISOTOPE BEAMS

    NARCIS (Netherlands)

    Krasznahorkay, A.; Csatlos, M.; Stuhl, L.; Algora, A.; Gulyas, J.; Timar, J.; Paar, N.; Vretenar, D.; Harakeh, M. N.

    A new method, based on the excitation of the anti-analog giant dipole resonance (AGDR) in (p, n) reaction, for measuring the neutron-skin thickness has been tested. The gamma-decay of the AGDR to the isobaric analog state (IAS) has been measured. The difference in excitation energy of the AGDR and

  1. Measurement of sheath thickness by lining out grooves in the Hall-type stationary plasma thrusters

    International Nuclear Information System (INIS)

    Yu Daren; Wu Zhiwen; Ning Zhongxi; Wang Xiaogang

    2007-01-01

    Using grooves created along the axial direction of the discharge channel, a method for measuring sheath thickness in Hall-type stationary plasma thrusters has been developed. By distorting the wall surface using these grooves, it is possible to numerically study the effect of the wall surface on the sheath and near wall conductivity. Monte Carlo method is applied to calculate the electron temperature variation with different groove depths. The electron dynamic process in the plasma is described by a test particle method with the electron randomly entering the sheath from the discharge channel and being reflected back. Numerical results show that the reflected electron temperature is hardly affected by the wall surface if the groove depth is much less than the sheath thickness. On the other hand, the reflected electron temperature increases if the groove depth is much greater than the sheath thickness. The reflected electron temperature has a sharp jump when the depth of groove is on the order of the sheath thickness. The simulation is repeated with different sheath thicknesses and the results are the same. Therefore, a diagnosis mean of the sheath thickness can be developed based on the method. Also the simulation results are in accord with the experimental data. Besides, the measurement method may be applicable to other plasma device with similar orthogonal steady state electrical and magnetic fields

  2. Quantitative analysis and metallic coating thickness measurements by X-ray fluorescence

    International Nuclear Information System (INIS)

    Negrea, Denis; Ducu, Catalin; Malinovschi, Viorel; Moga, Sorin; Boicea, Niculae

    2009-01-01

    Full text: This paperwork covers the use of X-ray fluorescence (XRF) for determining the concentration and the coating thickness on metallic samples. The analysis method presented here may also be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF, such as the absorption coefficient of the system, primary radiation, fluorescent radiation and type of detection. For the coating thickness measurement it was used the substrate-line attenuation method and a computing algorithm was developed. Its advantage relies in the fact that no special calibration with standard samples having different layer thickness is needed. The samples used for evaluation were metallic pieces of iron with zinc-nickel coatings of different thickness obtained by electrochemical deposition. (authors)

  3. Quantitative analysis and metallic coating thickness measurements by X-ray fluorescence

    International Nuclear Information System (INIS)

    Negrea, Denis; Ducu, Catalin; Malinovschi, Viorel; Moga, Sorin; Boicea, Niculae

    2009-01-01

    This work deals with the use of X-ray fluorescence (XRF) for determining the concentration and the coating thickness on metallic samples. The analysis method presented here may also be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF, such as the absorption coefficient of the system, primary radiation, fluorescent radiation and type of detection. For the coating thickness measurement it was used the substrate-line attenuation method and an algorithm was developed. Its advantage relies in the fact that no special calibration with standard samples having different layer thickness is needed. The samples used for evaluation were metallic pieces of iron with zinc-nickel coatings of different thickness obtained by electrochemical deposition. (authors)

  4. Thin layer thickness measurements by zero group velocity Lamb mode resonances

    Science.gov (United States)

    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.

  5. Retinal nerve fibre layer thickness measurements in normal Indian population by optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Ramakrishnan R

    2006-01-01

    Full Text Available Purpose: To obtain retinal nerve fibre layer thickness measurements by optical coherence tomography (OCT in normal Indian population. Materials and Methods: Total of 118 randomly selected eyes of 118 normal Indian subjects of both sex and various age groups underwent retinal nerve fiber layer thickness analysis by Stratus OCT 3000 V 4.0.1. The results were evaluated and compared to determine the normal retinal nerve fiber layer thickness measurements and its variations with sex and age. Results: Mean + standard deviation retinal nerve fiber layer thickness for various quadrants of superior, inferior, nasal, temporal, and along the entire circumference around the optic nerve head were 138.2 + 21.74, 129.1 + 25.67, 85.71 + 21, 66.38 + 17.37, and 104.8 + 38.81 µm, respectively. There was no significant difference in the measurements between males and females, and no significant correlation with respect to age. Conclusion: Our results provide the normal retinal nerve fiber layer thickness measurements and its variations with age and sex in Indian population.

  6. Sea-ice thickness from field measurements in the northwestern Barents Sea

    Science.gov (United States)

    King, Jennifer; Spreen, Gunnar; Gerland, Sebastian; Haas, Christian; Hendricks, Stefan; Kaleschke, Lars; Wang, Caixin

    2017-02-01

    The Barents Sea is one of the fastest changing regions of the Arctic, and has experienced the strongest decline in winter-time sea-ice area in the Arctic, at -23±4% decade-1. Sea-ice thickness in the Barents Sea is not well studied. We present two previously unpublished helicopter-borne electromagnetic (HEM) ice thickness measurements from the northwestern Barents Sea acquired in March 2003 and 2014. The HEM data are compared to ice thickness calculated from ice draft measured by ULS deployed between 1994 and 1996. These data show that ice thickness varies greatly from year to year; influenced by the thermodynamic and dynamic processes that govern local formation vs long-range advection. In a year with a large inflow of sea-ice from the Arctic Basin, the Barents Sea ice cover is dominated by thick multiyear ice; as was the case in 2003 and 1995. In a year with an ice cover that was mainly grown in situ, the ice will be thin and mechanically unstable; as was the case in 2014. The HEM data allow us to explore the spatial and temporal variability in ice thickness. In 2003 the dominant ice class was more than 2 years old; and modal sea-ice thickness varied regionally from 0.6 to 1.4 m, with the thinner ice being either first-year ice, or multiyear ice which had come into contact with warm Atlantic water. In 2014 the ice cover was predominantly locally grown ice less than 1 month old (regional modes of 0.5-0.8 m). These two situations represent two extremes of a range of possible ice thickness distributions that can present very different conditions for shipping traffic; or have a different impact on heat transport from ocean to atmosphere.

  7. Role of experimental resolution in measurements of critical layer thickness for strained-layer epitaxy

    International Nuclear Information System (INIS)

    Fritz, I.J.

    1987-01-01

    Experimental measurements of critical layer thicknesses (CLT's) in strained-layer epitaxy are considered. Finite experimental resolution can have a major effect on measured CLT's and can easily lead to spurious results. The theoretical approach to critical layer thicknesses of J. W. Matthews [J. Vac. Sci. Technol. 12, 126 (1975)] has been modified in a straightforward way to predict the apparent critical thickness for an experiment with finite resolution in lattice parameter. The theory has also been modified to account for the general empirical result that fewer misfit dislocations are generated than predicted by equilibrium calculation. The resulting expression is fit to recent x-ray diffraction data on InGaAs/GaAs and SiGe/Si. The results suggest that CLT's in these systems may not be significantly larger than predicted by equilibrium theory, in agreement with high-resolution measurements

  8. Tundish Cover Flux Thickness Measurement Method and Instrumentation Based on Computer Vision in Continuous Casting Tundish

    Directory of Open Access Journals (Sweden)

    Meng Lu

    2013-01-01

    Full Text Available Thickness of tundish cover flux (TCF plays an important role in continuous casting (CC steelmaking process. Traditional measurement method of TCF thickness is single/double wire methods, which have several problems such as personal security, easily affected by operators, and poor repeatability. To solve all these problems, in this paper, we specifically designed and built an instrumentation and presented a novel method to measure the TCF thickness. The instrumentation was composed of a measurement bar, a mechanical device, a high-definition industrial camera, a Siemens S7-200 programmable logic controller (PLC, and a computer. Our measurement method was based on the computer vision algorithms, including image denoising method, monocular range measurement method, scale invariant feature transform (SIFT, and image gray gradient detection method. Using the present instrumentation and method, images in the CC tundish can be collected by camera and transferred to computer to do imaging processing. Experiments showed that our instrumentation and method worked well at scene of steel plants, can accurately measure the thickness of TCF, and overcome the disadvantages of traditional measurement methods, or even replace the traditional ones.

  9. Reliability of ultrasound thickness measurement of the abdominal muscles during clinical isometric endurance tests.

    Science.gov (United States)

    ShahAli, Shabnam; Arab, Amir Massoud; Talebian, Saeed; Ebrahimi, Esmaeil; Bahmani, Andia; Karimi, Noureddin; Nabavi, Hoda

    2015-07-01

    The study was designed to evaluate the intra-examiner reliability of ultrasound (US) thickness measurement of abdominal muscles activity when supine lying and during two isometric endurance tests in subjects with and without Low back pain (LBP). A total of 19 women (9 with LBP, 10 without LBP) participated in the study. Within-day reliability of the US thickness measurements at supine lying and the two isometric endurance tests were assessed in all subjects. The intra-class correlation coefficient (ICC) was used to assess the relative reliability of thickness measurement. The standard error of measurement (SEM), minimal detectable change (MDC) and the coefficient of variation (CV) were used to evaluate the absolute reliability. Results indicated high ICC scores (0.73-0.99) and also small SEM and MDC scores for within-day reliability assessment. The Bland-Altman plots of agreement in US measurement of the abdominal muscles during the two isometric endurance tests demonstrated that 95% of the observations fall between the limits of agreement for test and retest measurements. Together the results indicate high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all the positions tested. According to the study's findings, US imaging can be used as a reliable method for assessment of abdominal muscles activity in supine lying and the two isometric endurance tests employed, in participants with and without LBP. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  11. Measurement of the thickness and homogeneity of thin foils by slowing down alpha particles

    International Nuclear Information System (INIS)

    Bimbot, R.; Della Negra, S.; Deprun, C.; Gardes, D.; Rivet, M.F.

    1979-01-01

    The energy loss of 8.785 MeV α particles passing through a thin foil is used to measure the foil thickness. The measurement is performed in various points of the target, the abscissa and ordinate of which are set with precision from the outside of the chamber. This gives a thickness map of the target. The working up of the data, and the use of energy loss tables are made in a standard way. The absolute uncertainty is of some percent for 100 μg/cm 2 foils. The technique has been refined to reach the same precision for 10 μg/cm 2 targets [fr

  12. Measurement of gingival thickness using digital vernier caliper and ultrasonographic method: a comparative study.

    Science.gov (United States)

    Sharma, Swati; Thakur, Srinath L; Joshi, Shyamsunder K; Kulkarni, Sudhindra S

    2014-05-01

    The measurement of the thickness of the gingival tissues has been done using different techniques. Trans-gingival probing with a graduated probe, use of vernier calipers, ultrasonography and cone-beam computed tomography (CBCT), have all been tried, but no one technique has been shown to be consistent and better than the others. The present study was done to evaluate and compare the gingival thickness as measured with a digital vernier caliper and ultrasonography. A total of 30 systemically healthy, non-smokers were included in the study. The gingival measurements were made and recorded from the maxillary and mandibular lateral incisor areas at 2 locations: (a) at a point apical to the free gingival groove; and (b) at a point immediately coronal to the muco-gingival junction. The mean gingival thickness ranged from 0.56 to 1.02 mm. Males had a significantly thicker gingiva as compared to females (P caliper and those made with ultrasonography were compared. The thickness of the gingiva was in the range of 0.56-1.02 mm. A digital vernier caliper and ultrasonography both can be used to assess the gingival thickness with equal accuracy. © 2013 Wiley Publishing Asia Pty Ltd.

  13. Laser-based diagnostics for the measurement of liquid water film thickness.

    Science.gov (United States)

    Greszik, Daniel; Yang, Huinan; Dreier, Thomas; Schulz, Christof

    2011-02-01

    Three different diagnostic techniques are investigated for measurement of the thickness of liquid water films deposited on a transparent quartz plate. The methods are based on laser-induced fluorescence (LIF) from low concentrations of a dissolved tracer substance and spontaneous Raman scattering of liquid water, respectively, both excited with 266 nm of radiation, and diode laser absorption spectroscopy (DLAS) in the near-infrared spectral region. Signal intensities are calibrated using liquid layers of known thickness between 0 and 1000 μm. When applied to evaporating liquid water films, the thickness values derived from the direct DLAS and Raman scattering measurements correlate well with each other as a function of time after the start of data recording, while the LIF signal derived thickness values decrease faster with time due to selective tracer evaporation from the liquid. The simultaneous application of the LIF with a tracer-free detection technique can serve as an in situ reference for quantitative film thickness measurements.

  14. Diode laser-based standoff absorption measurement of water film thickness in retro-reflection

    Science.gov (United States)

    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.

  15. Calculated /alpha/-induced thick target neutron yields and spectra, with comparison to measured data

    International Nuclear Information System (INIS)

    Wilson, W.B.; Bozoian, M.; Perry, R.T.

    1988-01-01

    One component of the neutron source associated with the decay of actinide nuclides in many environments is due to the interaction of decay /alpha/ particles in (/alpha/,n) reactions on low Z nuclides. Measurements of (/alpha/,n) thick target neutron yields and associated neutron spectra have been made for only a few combinations of /alpha/ energy and target nuclide or mixtures of actinide and target nuclides. Calculations of thick target neutron yields and spectra with the SOURCES code require /alpha/-energy-dependent cross sections for (/alpha/,n) reactions, as well as branching fractions leading to the energetically possible levels of the product nuclides. A library of these data has been accumulated for target nuclides of Z /le/ 15 using that available from measurements and from recent GNASH code calculations. SOURCES, assuming neutrons to be emitted isotopically in the center-of-mass system, uses libraries of /alpha/ stopping cross sections, (/alpha/,n) reaction cross reactions, product nuclide level branching fractions, and actinide decay /alpha/ spectra to calculate thick target (/alpha/,n) yields and neutron spectra for homogeneous combinations of nuclides. The code also calculates the thick target yield and angle intergrated neutron spectrum produced by /alpha/-particle beams on targets of homogeneous mixtures of nuclides. Illustrative calculated results are given and comparisons are made with measured thick target yields and spectra. 50 refs., 1 fig., 2 tabs

  16. Absorption coefficient of nearly transparent liquids measured using thermal lens spectrometry

    Directory of Open Access Journals (Sweden)

    H.Cabrera

    2006-01-01

    Full Text Available We use an optimized pump-probe mode-mismatched thermal lens scheme to determine the optical absorption coefficient and thermal diffusivity of ethanol, benzene, acetone, methanol, toluene and chloroform. In this scheme the excitation beam is focused in the presence of a collimated probe beam. The agreement between experimentally obtained results and values reported in the literature is good.

  17. Evaluation of the x-ray fluorescence method of precious metal plating thickness measurements. Technological spinoff report

    International Nuclear Information System (INIS)

    Carson, J.S.; Hearn, N.K.; Pettie, C.B.

    1975-09-01

    It is shown that gold and silver plating thickness measurements made using an x-ray spectrograph could be closely correlated with thicknesses measured from sectional samples. Good correlations were also shown for single overlays of gold over silver when each layer was less than 0.0003 inch thick

  18. Simultaneous Ultrasonic Measurement of Thickness and Speed of Sound in Elastic Plates Using Coded Excitation Signals.

    Science.gov (United States)

    Kiefer, Daniel A; Fink, Michael; Rupitsch, Stefan J

    2017-11-01

    Layer thickness and the speed of sound are important parameters for nondestructive testing applications. If one of the parameters is known, the other one can be determined by simple time-of-flight (TOF) measurement of ultrasound. However, often these parameters are both unknown. In this contribution, we examine and adapt ultrasonic imaging techniques using coded excitation signals to simultaneously measure the thickness and the speed of sound of homogeneous elastic plates of unknown material. Good axial resolution is required to measure thin samples. We present a new approach for transmission signal conditioning to improve axial resolution. This conditioning consists of enhancing spectral components that are damped by the transducer prior to transmit. Due to the long duration of coded excitation signals, pulse compression techniques are required for TOF measurements. Common pulse compression filters are discussed, and appropriate filtering of the compression waveform is designed to keep the sidelobe level (SLL) acceptably low. An experimental assessment of the presented measurement techniques reveals that the signal conditioning substantially increases the axial resolution. However, a tapered Wiener filter should be used for the best tradeoff between SLL and axial resolution. We used the proposed method to measure different plates of steel, aluminum, and polymethylmethacrylate of various thicknesses, and the results show very good agreement with the reference values, which we obtained with a micrometer screw and by standard TOF measurement, respectively. The relative error for the plate thickness is smaller than 2.2% and that for the speed of sound is smaller than 3%. It is remarkable that plate thickness could be measured down to 60% of the wavelength.

  19. Value of endometrial thickness measurement for diagnosing focal intrauterine pathology in women without abnormal uterine bleeding

    DEFF Research Database (Denmark)

    Dreisler, E; Sorensen, S Stampe; Ibsen, P H

    2009-01-01

    OBJECTIVE: To assess the diagnostic value of transvaginal sonographic (TVS) measurement of endometrial thickness for diagnosing focal intrauterine pathology in women without abnormal uterine bleeding (AUB). METHODS: A random selection from the Danish Civil Registration System was made: 1660 women...... aged 20-74 years were invited to participate and 686 women were eligible and accepted inclusion (429 pre- and 257 postmenopausal). The women underwent TVS measurement of endometrial thickness and saline contrast sonohysterography (SCSH). Hysteroscopic resection with histopathology (gold standard...... modulators (n = 2). Thus, 375 women without AUB were included (217 pre- and 158 postmenopausal). Receiver-operating characteristics (ROC) curves for endometrial thickness and focal lesion were analyzed. RESULTS: Focal intrauterine pathology was confirmed in 41 women (35 with polyps, five with submucosal...

  20. Development of an in-line X-ray reflectivity technique for metal film thickness measurement

    International Nuclear Information System (INIS)

    Windover, D.; Barnet, E.; Summers, J.; Gribbin, C.; Lu, T.-M.; Kumar, A.; Bakhru, H.; Lee, S.L.

    2001-01-01

    Non-destructive measurement of thin film (particularly metal film) thickness less than 10 nm has been a challenging task. In this work, we showed that it is possible to obtain the thickness of ultra-thin tantalum films within seconds using a fixed-angle, energy dispersive X-ray reflectivity technique by a conventional, low-energy X-ray copper or chromium source (20 kV/20 mA/400W) and using Parratt reflectivity modeling. We compared this fixed angle, energy dispersive result with more conventional fixed energy, angular dispersive reflectivity to establish the validity of the method and provide error estimates for fast thickness modeling. This X-ray technique is particularly useful for very thin diffusion barrier measurements in future microelectronics applications

  1. Comparing electron tomography and HRTEM slicing methods as tools to measure the thickness of nanoparticles

    International Nuclear Information System (INIS)

    Alloyeau, D.; Ricolleau, C.; Oikawa, T.; Langlois, C.; Le Bouar, Y.; Loiseau, A.

    2009-01-01

    Nanoparticles' morphology is a key parameter in the understanding of their thermodynamical, optical, magnetic and catalytic properties. In general, nanoparticles, observed in transmission electron microscopy (TEM), are viewed in projection so that the determination of their thickness (along the projection direction) with respect to their projected lateral size is highly questionable. To date, the widely used methods to measure nanoparticles thickness in a transmission electron microscope are to use cross-section images or focal series in high-resolution transmission electron microscopy imaging (HRTEM 'slicing'). In this paper, we compare the focal series method with the electron tomography method to show that both techniques yield similar particle thickness in a range of size from 1 to 5 nm, but the electron tomography method provides better statistics since more particles can be analyzed at one time. For this purpose, we have compared, on the same samples, the nanoparticles thickness measurements obtained from focal series with the ones determined from cross-section profiles of tomograms (tomogram slicing) perpendicular to the plane of the substrate supporting the nanoparticles. The methodology is finally applied to the comparison of CoPt nanoparticles annealed ex situ at two different temperatures to illustrate the accuracy of the techniques in detecting small particle thickness changes.

  2. Comparing electron tomography and HRTEM slicing methods as tools to measure the thickness of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Alloyeau, D., E-mail: alloyeau.damien@gmail.com [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Laboratoire d' Etude des Microstructures - ONERA/CNRS, UMR 104, B.P. 72, 92322 Chatillon (France); Ricolleau, C. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Oikawa, T. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); JEOL (Europe) SAS, Espace Claude Monet, 1 Allee de Giverny, 78290 Croissy-sur-Seine (France); Langlois, C. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Le Bouar, Y.; Loiseau, A. [Laboratoire d' Etude des Microstructures - ONERA/CNRS, UMR 104, B.P. 72, 92322 Chatillon (France)

    2009-06-15

    Nanoparticles' morphology is a key parameter in the understanding of their thermodynamical, optical, magnetic and catalytic properties. In general, nanoparticles, observed in transmission electron microscopy (TEM), are viewed in projection so that the determination of their thickness (along the projection direction) with respect to their projected lateral size is highly questionable. To date, the widely used methods to measure nanoparticles thickness in a transmission electron microscope are to use cross-section images or focal series in high-resolution transmission electron microscopy imaging (HRTEM 'slicing'). In this paper, we compare the focal series method with the electron tomography method to show that both techniques yield similar particle thickness in a range of size from 1 to 5 nm, but the electron tomography method provides better statistics since more particles can be analyzed at one time. For this purpose, we have compared, on the same samples, the nanoparticles thickness measurements obtained from focal series with the ones determined from cross-section profiles of tomograms (tomogram slicing) perpendicular to the plane of the substrate supporting the nanoparticles. The methodology is finally applied to the comparison of CoPt nanoparticles annealed ex situ at two different temperatures to illustrate the accuracy of the techniques in detecting small particle thickness changes.

  3. Ultrasound and histological measurements of dividing membrane thickness in twin gestations.

    Science.gov (United States)

    Bracero, L A; Huff, C; Blitz, M J; Plata, M J; Seybold, D J; Broce, M

    2017-10-01

    To determine how prenatal ultrasound measurements of dividing membrane thickness correlate with postnatal histological measurements and chorionicity in twin gestations. This was a prospective, longitudinal cohort study of twin gestations. Dividing membrane thickness was measured by transabdominal ultrasound, with the insonation beam both parallel and perpendicular to the membrane, in the second or third trimester, depending on when care was established. Ultrasound examinations were performed every 4 weeks following initial assessment until delivery. Measurements of membrane thickness from the first ultrasound examination were compared with histological measurements after delivery. A total of 45 twin pregnancies (32 dichorionic, 13 monochorionic) were included. Mean gestational age at initial ultrasound examination was 24.1 ± 7.3 weeks. Parallel ultrasound measurements of membrane thickness were 1.6 ± 0.8 mm for monochorionic and 2.5 ± 0.9 mm for dichorionic gestations (P = 0.001). Perpendicular ultrasound measurements were 1.6 ± 0.3 mm for monochorionic and 2.2 ± 0.8 mm for dichorionic gestations (P = 0.009). Inter- and intraobserver reliability of ultrasound measurements were 0.847 and 0.950, respectively. Parallel and perpendicular ultrasound measurements correlated better with each other (R = 0.807, P membrane thickness (R parallel  = 0.538, P Receiver-operating characteristics curve analyses to predict histological membrane thickness > 50 th percentile resulted in an area under the curve (AUC) of 0.828 for parallel (P membrane thickness is positively correlated with postnatal histological measurement. Dichorionicity can be determined by a magnified dividing membrane thickness ≥ 1.9 mm. Measurements with the ultrasound beam parallel to the dividing membrane may be more accurate than perpendicular measurements. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016

  4. Performance of a fiber optic sensor for online measurement of coating thickness

    Science.gov (United States)

    D'Emilia, Giulio

    1999-01-01

    Some aspects concerning a methodology for the measurement of thickness of dry and wet coatings which is based on a fiber optic probe are discussed in order to verify the feasibility of this approach and the capability of such a probe of on- line measuring. In this preliminary step of the research some problems discussed mainly concerning the methodology which has been proposed and which is based on the measuring of the reflectance of the coating plated on thin steel sheets for use in the food industry. Furthermore the effect of the main interfering and modifying quantities is discussed both theoretically and experimentally when the measurement has to be carried out in order to allow on-line coating thickness measurements with satisfactory accuracy.

  5. Thin-film thickness measurement using x-ray peak ratioing in the scanning electron microscope

    International Nuclear Information System (INIS)

    Elliott, N.E.; Anderson, W.E.; Archuleta, T.A.; Stupin, D.M.

    1981-01-01

    The procedure used to measure laser target film thickness using a scanning electron microscope is summarized. This method is generally applicable to any coating on any substrate as long as the electron energy is sufficient to penetrate the coating and the substrate produces an x-ray signal which can pass back through the coating and be detected

  6. Correction of thickness measurement errors for two adjacent sheet structures in MR images

    International Nuclear Information System (INIS)

    Cheng Yuanzhi; Wang Shuguo; Sato, Yoshinobu; Nishii, Takashi; Tamura, Shinichi

    2007-01-01

    We present a new method for measuring the thickness of two adjacent sheet structures in MR images. In the hip joint, in which the femoral and acetabular cartilages are adjacent to each other, a conventional measurement technique based on the second derivative zero crossings (called the zero-crossings method) can introduce large underestimation errors in measurements of cartilage thickness. In this study, we have developed a model-based approach for accurate thickness measurement. We model the imaging process for two adjacent sheet structures, which simulate the two articular cartilages in the hip joint. This model can be used to predict the shape of the intensity profile along the sheet normal orientation. Using an optimization technique, the model parameters are adjusted to minimize the differences between the predicted intensity profile and the actual intensity profiles observed in the MR data. The set of model parameters that minimize the difference between the model and the MR data yield the thickness estimation. Using three phantoms and one normal cadaveric specimen, the usefulness of the new model-based method is demonstrated by comparing the model-based results with the results generated using the zero-crossings method. (author)

  7. Radiographic technique and brackets affect measurements of proximal enamel thickness on mandibular incisors

    NARCIS (Netherlands)

    Ang, Amy Giok Phing; Steegmans, Pauline Antoinette Josephine; Kerdijk, Wouter; Livas, Christos; Ren, Yijin

    2017-01-01

    Objective: To investigate the influence of radiographic film and tube positioning, the presence and the size of brackets on in vitro measurements of proximal enamel thickness of mandibular incisors on periapical radiographs aimed to aid planning of interproximal enamel reduction procedures in

  8. Low-energy cross section measurements through detection of secondary gamma emission and thick target

    Energy Technology Data Exchange (ETDEWEB)

    Barron P, L.; Chavez L, E.; Huerta H, A.; Ortiz, M.E. [Instituto de Fisica UNAM, A.P. 20-364, 04510 Mexico, D.F. (Mexico); Murillo O, G.; Aguilera, E.F.; Martinez Q, E.; Moreno B, E.; Policroniades R, R.; Varela G, A. [Instituto Nacional de Investigaciones Nucleares, Departamento del Acelerador, A.P. 18-1027, 11801, Mexico, D.F. (Mexico)

    2004-12-01

    In this work, the detection of secondary gamma rays in a tightly shielded Germanium detector, together with a high intensity heavy ion beam on a thick target is used to measure the fusion cross section for the {sup 12} C + {sup 12} C system at very low energies. (Author) 14 refs., 1 tab., 8 figs.

  9. An optical method for measuring the thickness of a falling condensate in gravity assisted heat pipe

    Directory of Open Access Journals (Sweden)

    Kasanický Martin

    2015-01-01

    Full Text Available A large number of variables is the main problem of designing systems which uses heat pipes, whether it is a traditional - gravity, or advanced - capillary, pulsating, advanced heat pipes. This article is a methodology for measuring the thickness of the falling condensate in gravitational heat pipes, with using the optical triangulation method, and the evaluation of risks associated with this method.

  10. Measuring method and device for thickness of pad welded joint of reactor pressure vessel

    International Nuclear Information System (INIS)

    Ara, Katsuyuki; Nakajima, Nobuya; Ebine, Noriya.

    1995-01-01

    A magnetic yoke having an optional magnetic path length and a magnetic path cross section is disposed in close contact with or adjacent to the surface of the pad welded joint of a reactor pressure vessel, to form a magnetic path by the magnetic yoke and the reactor pressure vessel. Then, the magnetic path yoke is magnetized to measure a distribution of a magnetic field generated on the surface of the pad welded joint or its vicinity to which the magnetic yoke is adapted to be in close contact or come close. Since the geometrical dimensions and the magnetic performances of a material of the magnetic yoke and the pressure vessel are previously determined and, the measured magnetic distribution changes only by the thickness of the pad welded joint, the thickness of the pad welded joint of the pressure vessel can be determined. Accordingly, the measuring method of the present invention can measure the thickness of the pad welded joint of the pressure vessel at a desired practical accuracy and at a resolution power of, for example, 0.1mm relative to the thickness of the seat welded joint of 5 to 10mm. (N.H.)

  11. Femoral cartilage thickness measurements in healthy individuals: learning, practicing and publishing with TURK-MUSCULUS.

    Science.gov (United States)

    Özçakar, Levent; Tunç, Hakan; Öken, Öznur; Ünlü, Zeliha; Durmuş, Bekir; Baysal, Özlem; Altay, Zuhal; Tok, Fatih; Akkaya, Nuray; Doğu, Beril; Çapkın, Erhan; Bardak, Ayşenur; Çarlı, Alparslan Bayram; Buğdaycı, Derya; Toktaş, Hasan; Dıraçoğlu, Demirhan; Gündüz, Berrin; Erhan, Belgin; Kocabaş, Hilal; Erden, Gül; Günendi, Zafer; Kesikburun, Serdar; Omaç, Özlem Köroğlu; Taşkaynatan, Mehmet Ali; Şenel, Kazım; Uğur, Mahir; Yalçınkaya, Ebru Yılmaz; Öneş, Kadriye; Atan, Çiğdem; Akgün, Kenan; Bilgici, Ayhan; Kuru, Ömer; Özgöçmen, Salih

    2014-01-01

    Measurement of the femoral cartilage thickness by using in-vivo musculoskeletal ultrasonography (MSUS) has been previously shown to be a valid and reliable method in previous studies; however, to our best notice, normative data has not been provided before in the healthy population.The aim of our study was to provide normative data regarding femoral cartilage thicknesses of healthy individuals with collaborative use of MSUS. This is across-sectional study run at Physical and Rehabilitation Medicine Departments of 18 Secondary and Tertiary Centers in Turkey. 1544 healthy volunteers (aged between 25-40 years) were recruited within the collaboration of TURK-MUSCULUS (Turkish Musculoskeletal Ultrasonography Study Group). Subjects who had a body mass index value of less than 30 and who did not have signs and symptoms of any degenerative/inflammatory arthritis or other rheumatic diseases, history of knee trauma and previous knee surgery were enrolled. Ultrasonographic measurements were performed axially from the suprapatellar window by using linear probes while subjects' knees were in maximum flexion. Three (mid-point) measurements were taken from both knees (lateral condyle, intercondylar area, medial condyle). A total of 2876 knees (of 817 M, 621 F subjects) were taken into analysis after exclusion of inappropriate images. Mean cartilage thicknesses were significantly lower in females than males (all p< 0.001). Thickness values negatively correlated with age; negatively (females) and positively (males) correlated with smoking. Men who regularly exercised had thicker cartilage than who did not exercise (all p < 0.05). Increased age (in both sexes) and absence of exercise (males) were found to be risk factors for decreased cartilage thicknesses. Further data pertaining to other countries would be interesting to uncover whether ethnic differences also affect cartilage thickness. Collaborative use of MSUS seems to be promising in this regard.

  12. The importance of ultrasonographic measurement of peritoneal wall thickness in pediatric chronic peritoneal dialysis patients.

    Science.gov (United States)

    Yavaşcan, Önder; Aksu, Nejat; Alparslan, Caner; Sarıtaş, Serdar; Elmas, Cengiz Han; Eraslan, Ali Nihat; Duman, Soner; Mir, Sevgi

    2015-04-01

    Loss of peritoneal function due to peritoneal fibrosing syndrome (PFS) is a major factor leading to treatment failure in chronic peritoneal dialysis (PD) patients. Although the precise biologic mechanisms responsible for these changes have not been defined, the general assumption is that alterations in peritoneal function are related to structural changes in the peritoneal membrane. Studies of the peritoneal membrane by non-invasive ultrasonography (US) in chronic PD patients are limited. The aim of the present study is to assess the relationship between functional parameters of peritoneum and peritoneal thickness measured by US in children treated by chronic PD. We recruited two groups of patients: 23 subjects (13 females, 10 males) on chronic PD (patient group) and 26 (7 females, 19 males) on predialysis out-patient follow-up (creatinine clearance: 20-60 mL/min/1.73 m(2)) (control group). Age, sex, weight, height, body mass index (BMI), chronic PD duration, episodes of peritonitis and the results of peritoneal equilibration test (PET) were recorded. Hemoglobin (Hb), blood pressure (BP), left ventricular mass index (LVMI) and renal osteodystrophy (ROD) parameters were also obtained. The thickness of the parietal peritoneum was measured by trans-abdominal US in all children. Statistical analyses were performed by using Student's t and Pearson's correlation tests. Mean peritoneal thickness in chronic PD patients (1028.26 ± 157.26 μm) was significantly higher than control patients (786.52 ± 132.33). Mean peritoneal thickness was significantly correlated with mean body height (R(2) = 0.93, p peritonitis (R(2) = 0.93, p peritoneal thickness and Hb, BP, LVMI and ROD parameters. In conclusion, ultrasonographic measurement of peritoneal membrane thickness is a simple and non-invasive method in chronic PD children. This diagnostic tool likely enables to assess peritoneal structure and function in these patients.

  13. Association of digital cushion thickness with sole temperature measured with the use of infrared thermography.

    Science.gov (United States)

    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

  14. Measurement of neutron yield by 62 MeV proton beam on a thick Beryllium target

    International Nuclear Information System (INIS)

    Alba, R; Cosentino, G; Zoppo, A Del; Pietro, A Di; Figuera, P; Finocchiaro, P; Maiolino, C; Santonocito, D; Schillaci, M; Barbagallo, M; Colonna, N; Boccaccio, P; Esposito, J; Celentano, A; Osipenko, M; Ricco, G; Ripani, M; Viberti, C M; Kostyukov, A

    2013-01-01

    In the framework of research on IVth generation reactors and high intensity neutron sources a low-power prototype neutron amplifier was recently proposed by INFN. It is based on a low-energy, high current proton cyclotron, whose beam, impinging on a thick Beryllium converter, produces a fast neutron spectrum. The world database on the neutron yield from thick Beryllium target in the 70 MeV proton energy domain is rather scarce. The new measurement was performed at LNS, covering a wide angular range from 0 to 150 degrees and an almost complete neutron energy interval. In this contribution the preliminary data are discussed together with the proposed ADS facility.

  15. Measurement of the thickness of tubes with the aid of an internal ultrasonic probe

    International Nuclear Information System (INIS)

    Boulanger, G.; Furlan, J.

    1984-10-01

    This study concerns the adjustment of internal probes for ultrasonic testing of small tubes (internal diameter from 20 to 42 mm). The present probes allow to measure the thickness in the straight parts of these tubes, and can pass the curved parts. The principle of the measurement is presented: a annular transducer emits an ultrasonic beam to a conic mirror which reflects this last one perpendicular to the tube. The annular piezo-electric element of the transducers are divided in 8 sectors which give as much measurements by section. An electronic apparatus has been fitted, the MEPUS 8S, which realizes a quick commutation between the sectors and makes the measurement of the real or the relative thickness for each channel. A test on site has been undertaken to test the capacities of the system in an industrial environment [fr

  16. Sonographic assessment of fatty liver infiltration using the measurement of para- and perirenal fat thickness.

    Science.gov (United States)

    Kawasaki, Satsuki; Hasegawa, Osamu; Satoh, Shinobu; Numata, Kazushi; Terauchi, Yasuo

    2010-01-01

    Usefulness of abdominal ultrasonography for quantitative estimation of fatty liver by measurement of para- and perirenal sonographic fat thickness (UFT) was investigated. Study subjects were 286 patients hospitalized for the treatment of diabetes. These subjects underwent blood chemistry studies, abdominal ultrasonography, and CT. On sonography, the thickness of combined para- and perirenal fat was measured between the kidney and the inner aspect of the abdominal musculature. Measurements on both sides were averaged as the UFT. Fatty liver infiltration was graded on a scale of grade 0 to 3: 0, none; 1, mild; 2, moderate; and 3, severe. With abdominal CT, the ratio of CT attenuation value of the liver to that of the spleen (L/S ratio) was measured. A positive correlation was found between UFT and FL grade or between UFT and L/S ratio (p fat.

  17. Multi-wavelength thermal-lens spectrometry for high-accuracy measurements of absorptivities and quantum yields of photodegradation of a hemoprotein–lipid complex

    Directory of Open Access Journals (Sweden)

    Kseniya Tishchenko

    2017-09-01

    Full Text Available Accurate measurements of absorptivities and quantum yields of biochemical species under various conditions are an important task of applied photonics and analytical chemistry. In this work, we provide a comparison of the capabilities of thermal-lens spectrometry to measure these parameters of various samples. Measurements of relevant model substances, biologically active substituted 2-thiohydantoins and their complexes of copper(I,II and heme proteins (forms of hemoglobin and cytochrome c, showed negligible differences in apparent molar absorptivities for thermal-lens spectrometry and optical-absorption (spectrophotometric data. The values for tabletop and microscale thermal-lens measurements under batch conditions differ insignificantly. The precision of measurements of molar absorptivities by thermal-lens spectrometry is no less than in the case of spectrophotometry or the precision is even higher in the cases of low absorptivities. For cardiolipin–cytochrome c-NO complex, the difference between absorptivity values calculated from thermal-lens data and acquired by spectrophotometry is significant due to complex photodegradation. The quantum yield of its photolysis reaction calculated from optical absorption and thermal-lens data altogether at two wavelengths for 0.4–360 s of the reaction, 0.46 ± 0.04, was estimated.

  18. An examination of mass thickness measurements with X-ray sources

    International Nuclear Information System (INIS)

    Chen Mincong; Li Hongmei; Chen Ziyu; Shen Ji

    2008-01-01

    A method using X-rays to measure mass thickness is discussed. The method utilizes a filter to absorb low energy and characteristic photons so that the hardened X-ray spectra have a peaked energy distribution. An equivalent X-ray energy, which defines the attenuation in a material of interest can be used. The effect on the X-ray spectra of different filters is examined with Monte Carlo simulation using the EGSnrc package. A theoretical model for X-ray absorption that shows that the method can achieve good precision for a certain range of mass thicknesses is advanced. Experimental results agree well with the theoretical analysis. It is found that for a certain range of mass thicknesses, the relative error can be less than 1% for the aluminum alloy sample at the tube voltage of 30 or 45 kV

  19. An examination of mass thickness measurements with X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Chen Mincong; Li Hongmei; Chen Ziyu [Department of Modern Physics, University of Science and Technology of China, Jin Zhai Road, Hefei 230026 (China); Shen Ji [Department of Modern Physics, University of Science and Technology of China, Jin Zhai Road, Hefei 230026 (China)], E-mail: shenji@ustc.edu.cn

    2008-10-15

    A method using X-rays to measure mass thickness is discussed. The method utilizes a filter to absorb low energy and characteristic photons so that the hardened X-ray spectra have a peaked energy distribution. An equivalent X-ray energy, which defines the attenuation in a material of interest can be used. The effect on the X-ray spectra of different filters is examined with Monte Carlo simulation using the EGSnrc package. A theoretical model for X-ray absorption that shows that the method can achieve good precision for a certain range of mass thicknesses is advanced. Experimental results agree well with the theoretical analysis. It is found that for a certain range of mass thicknesses, the relative error can be less than 1% for the aluminum alloy sample at the tube voltage of 30 or 45 kV.

  20. Nondestructive measurement of homoepitaxially grown GaN film thickness with Fourier transform infrared spectroscopy

    Science.gov (United States)

    Horikiri, Fumimasa; Narita, Yoshinobu; Yoshida, Takehiro

    2017-12-01

    In vertical devices containing GaN homoepitaxial layers on GaN substrates, the layer thickness is a key parameter that needs to be clarified before starting the device process. We applied Fourier transform infrared spectroscopy (FT-IR) to a homoepitaxially grown GaN film that consisted of an n--GaN layer. The estimated film thickness from the FT-IR spectrum agreed well with the results of cross-sectional scanning electron microscope cathodoluminescence images. This is the first report of nondestructive film thickness measurements for homoepitaxially grown GaN and indicates the applicability of FT-IR to the nondestructive inspection of vertical GaN power devices.

  1. Measurements of liquid film thickness, concentration, and temperature of aqueous urea solution by NIR absorption spectroscopy

    Science.gov (United States)

    Pan, R.; Jeffries, J. B.; Dreier, T.; Schulz, C.

    2016-01-01

    A multi-wavelength near-infrared (NIR) diode laser absorption sensor has been developed and demonstrated for real-time monitoring of the thickness, solute concentration, and temperature of thin films of urea-water solutions. The sensor monitors the transmittance of three near-infrared diode lasers through the thin liquid film. Film thickness, urea mass fraction, and liquid temperature were determined from measured transmittance ratios of suitable combinations of lasers. Available laser wavelengths were selected depending on the variation of the NIR absorption spectrum of the solution with temperature and solute concentration. The spectral database was measured by a Fourier transform infrared spectrometer in the range 5500-8000 cm-1 for urea solutions between 5 and 40 wt% and temperatures between 298 and 338 K. A prototype sensor was constructed, and the sensor concept was first validated with measurements using a calibration cell providing liquid layers of variable thickness (200-1500 µm), urea mass fraction (5-40 wt%) and temperature (298-318 K). Temporal variations of film thickness and urea concentration were captured during the constant-temperature evaporation of a liquid film deposited on an optically polished heated quartz flat.

  2. Effects of Coil Diameter in Thickness Measurement Using Pulsed Eddy Current Non-destructive Testing

    Science.gov (United States)

    Nisa Azaman, Khairun; Sophian, Ali; Nafiah, Faris

    2017-11-01

    Non-destructive testing (NDT) techniques are used in industry to evaluate the properties of a material, component or structure without causing any permanent damage. Among the techniques, pulsed eddy current (PEC) NDT is regarded as a new technique where a broadband pulse excitation is used, as opposed to single frequencies employed in conventional eddy current NDT. In this study, a 2D axisymmetric electromagnetic model of a PEC probe has been developed and it has been used to study the effects of the excitation coil diameter on the performance of PEC probes in sample thickness measurement. A PEC system has also been built to validate the model. Aluminium plates are used as the sample and they can be stacked up to replicate thickness from 1 mm to 10 mm. The results show that there is a very good correlation between the simulation and experimental results, with an average error of less than 10%. The results also suggest that the larger the diameter of the excitation coil, the deeper the penetration and therefore the larger the thickness measurement range. It has also been shown that although the larger diameters have deeper penetration, the smallest diameter has the highest sensitivity if normalization is not used. These conclusions indicate that coil diameter is an important parameter in a PEC probe design for thickness measurement applications.

  3. Normal bladder wall thickness measurement in healthy Iranian children, a cross-sectional study

    Science.gov (United States)

    Adibi, Atoosa; Kazemian, Afarin; Toghiani, Ali

    2014-01-01

    Background: Normal bladder function is necessary for micturition. Many causes such as urinary tract infection, bladder outlet obstruction, and neuropathic bladder can influence bladder wall thickness (BWT). This study was designed to determine normal BWT in Iranian children. Materials and Methods: This was a cross-sectional study done in Isfahan in 2012 comprising 82 children aged 2-14 years without any urinary complaint. We measured thickness of posterior and lateral walls of the bladder in all children. Mean bladder wall thickness (MBWT) and mean bladder volume (BV) were also calculated. Results: In this study, we included 82 children (40 boys and 42 girls). Patients’ mean age was 6.43 ± 2.89 years, mean weight was 21.32 ± 8.40 kg, mean height was 111.57 ± 20.51 cm, and mean Body Mass Index was 17.12 ± 4.93. Mean lateral bladder wall thickness (LBWT) was 1.75 ± 0.32 mm and mean posterior bladder wall thickness (PBWT) was 1.59 ± 0.34 mm. Mean BV was 111.65 ± 72.11 ml and MBWT was 1.67 ± 0.28 mm. BVW all Index (BVWI) was 1249.05 ± 701.67. Conclusions: LBWT was1.75 ± 0.32 mm and PBWT was 1.59 ± 0.34 mm. PMID:25250302

  4. Normal bladder wall thickness measurement in healthy Iranian children, a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Atoosa Adibi

    2014-01-01

    Full Text Available Background: Normal bladder function is necessary for micturition. Many causes such as urinary tract infection, bladder outlet obstruction, and neuropathic bladder can influence bladder wall thickness (BWT.This study was designed to determine normal BWT in Iranian children. Materials and Methods: This was a cross-sectional study done in Isfahan in 2012 comprising 82 children aged 2-14 years without any urinary complaint. We measured thickness of posterior and lateral walls of the bladder in all children. Mean bladder wall thickness (MBWT and mean bladder volume (BV were also calculated. Results: In this study, we included 82 children (40 boys and 42 girls. Patients′ mean age was 6.43 ± 2.89 years, mean weight was 21.32 ± 8.40 kg, mean height was 111.57 ± 20.51 cm, and mean Body Mass Index was 17.12 ± 4.93. Mean lateral bladder wall thickness (LBWT was 1.75 ± 0.32 mm and mean posterior bladder wall thickness (PBWT was 1.59 ± 0.34 mm. Mean BV was 111.65 ± 72.11 ml and MBWT was 1.67 ± 0.28 mm. BVW all Index (BVWI was 1249.05 ± 701.67. Conclusions: LBWT was1.75 ± 0.32 mm and PBWT was 1.59 ± 0.34 mm.

  5. Influence of veneer thickness on residual stress profile in veneering ceramic: measurement by hole-drilling.

    Science.gov (United States)

    Mainjot, Amélie K; Schajer, Gary S; Vanheusden, Alain J; Sadoun, Michaël J

    2012-02-01

    The veneering process of frameworks induces residual stresses and can initiate cracks when combined with functional stresses. The stress distribution within the veneering ceramic as a function of depth is a key factor influencing failure by chipping. This is a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the influence of veneer thickness on the stress profile in zirconia- and metal-based structures. The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The stress profile was measured in bilayered disc samples of 20 mm diameter, with a 1 mm thick zirconia or metal framework. Different veneering ceramic thicknesses were performed: 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm. All samples exhibited the same type of stress vs. depth profile, starting with compressive at the ceramic surface, decreasing with depth up to 0.5-1.0 mm from the surface, and then becoming compressive again near the framework, except for the 1.5 mm-veneered zirconia samples which exhibited interior tensile stresses. Stresses in the surface of metal samples were not influenced by veneer thickness. Variation of interior stresses at 1.2 mm from the surface in function of veneer thickness was inverted for metal and zirconia samples. Veneer thickness influences in an opposite way the residual stress profile in metal- and in zirconia-based structures. A three-step approach and the hypothesis of the crystalline transformation are discussed to explain the less favorable residual stress development in zirconia samples. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Non-contact Measurement of Remaining Thickness of Corroding Superheater Tubes. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Borggreen, Kjeld; Storesund, Jan

    2006-10-15

    Corrosion of superheaters has become a severe problem in many biomass boilers and incineration plants. This new situation calls for frequent tube wall thickness testing of the superheaters during very short shut-downs. To meet this demand Electro Magnetic Acoustic Transducer (EMAT) candidates as substitute for conventional manually operated contact UT-transducers. The EMAT can contactlessly generate an ultrasonic wave in the interphase between the external oxide and the metal. This means that measurements can be undertaken much quicker and with a much higher coverage simultaneously, without preceding blast operations. It is the aim of the project to demonstrate the usefulness of two simple EMAT systems, Panametrics and Sonatest, for fast and reliable tube thickness inspections in difficult-to-access superheater sections. The present Phase 1 of the project involves testing of the performance of the two systems in laboratory with the following results: 1. Both instruments work well on plate, tube, and pipe samples assuming the presence of an external oxide layer formed at a temperature above approximately 400 deg C. 2. Both instruments work well on all types of ferritic and martensitic steels but not on austenitic steels. 3. Both instruments work well independent of the thickness of the active oxide layer. 4. Both instruments work well independent of tube diameter, wall thickness, and sample width. 5. Both instruments work well over a very large range of wall thicknesses. Minimum tube wall thickness is less than 1.8 mm. 6. The tolerable lift-off (free distance between transducer and tube surface) is 2.4 - 3.0 mm for Panametrics system and 3.6 - 4.8 mm for Sonatest's system. The tolerable lift-off is a measure of the thickness of ash deposits, which can be tolerated on the tube surface as well as the misplacement, which can be tolerated in case of remote tube testing. 7. The tolerable off-set between tube axis and probe axis is very large for both instruments (10

  7. The Usefulness of Visceral Fat Thickness Measured by Ultrasonography as an Abdominal Obesity Index

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Kyun [Dept. of Diagnostic Radiology, Korealife Daejeon Healthcare Center, Daejeon (Korea, Republic of); Han, Man Seok [Dept. of Diagnostic Radiology, Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2008-09-15

    Abdominal obesity with visceral fat accumulation have been known to be intimately associated with the development of metabolic syndrome. Therefore, it is important to estimate the precise amount of visceral fat. Ultrasonography has been reported that it is a simple and noninvasive method for visceral fat evaluation. Purpose of this study is to evaluate the association of ultrasonographic visceral fat thickness, anthropometric indexes, and risk factor of metabolic syndrome, and to investigate the cut-off value of abdominal visceral fat thickness leading to increased risk of metabolic syndrome. The subject included 200 men and 200 women who visited D healthcare center in Daejeon from January to April 2008. The subcutaneous fat thickness and visceral fat thickness were measured by ultrasonograph. As anthropometric index, we measured body mass index, waist circumference and waist/height ratio. As for the risk factor of metabolic syndrome, we measured blood pressure, high density lipoprotein cholesterol, triglyceride and fasting serum glucose. VFT was significantly correlated with waist circumference, (r=0.683/M, r=0.604/F), waist to height ratio (r=0.633/M, r=0.593/F) and BMI (r=0.621/M, r=0.534/F) in both men and women. In addition it was significantly correlated with Systolic blood pressure (r=0.229/M, r=0.232/F), Diastolic blood pressure ((r=0.285/M, r=0.254/F), high density cholesterol (r=-0.254/M, r=-0.254/F), Triglyceride (r=0.475/M, r=0.411/F), and Fasting blood sugar (r=0.158/M, r=0.234/F) in both men and women. The cut-off value of visceral fat thickness leading to the increased risk of metabolic syndrome was 4.58 cm (sensitivity 89.2%, specificity 71.2%) in men and 3.50 cm (sensitivity 61.2% specificity 80.8%) in women respectively. The odds ratio of the risk of metabolic syndrome was dramatically increased with the abdominal visceral fat thickness level over 6 cm in men and 5 cm in women. The visceral fat thickness using ultrasonography was significantly

  8. The Usefulness of Visceral Fat Thickness Measured by Ultrasonography as an Abdominal Obesity Index

    International Nuclear Information System (INIS)

    Kim, Yong Kyun; Han, Man Seok

    2008-01-01

    Abdominal obesity with visceral fat accumulation have been known to be intimately associated with the development of metabolic syndrome. Therefore, it is important to estimate the precise amount of visceral fat. Ultrasonography has been reported that it is a simple and noninvasive method for visceral fat evaluation. Purpose of this study is to evaluate the association of ultrasonographic visceral fat thickness, anthropometric indexes, and risk factor of metabolic syndrome, and to investigate the cut-off value of abdominal visceral fat thickness leading to increased risk of metabolic syndrome. The subject included 200 men and 200 women who visited D healthcare center in Daejeon from January to April 2008. The subcutaneous fat thickness and visceral fat thickness were measured by ultrasonograph. As anthropometric index, we measured body mass index, waist circumference and waist/height ratio. As for the risk factor of metabolic syndrome, we measured blood pressure, high density lipoprotein cholesterol, triglyceride and fasting serum glucose. VFT was significantly correlated with waist circumference, (r=0.683/M, r=0.604/F), waist to height ratio (r=0.633/M, r=0.593/F) and BMI (r=0.621/M, r=0.534/F) in both men and women. In addition it was significantly correlated with Systolic blood pressure (r=0.229/M, r=0.232/F), Diastolic blood pressure ((r=0.285/M, r=0.254/F), high density cholesterol (r=-0.254/M, r=-0.254/F), Triglyceride (r=0.475/M, r=0.411/F), and Fasting blood sugar (r=0.158/M, r=0.234/F) in both men and women. The cut-off value of visceral fat thickness leading to the increased risk of metabolic syndrome was 4.58 cm (sensitivity 89.2%, specificity 71.2%) in men and 3.50 cm (sensitivity 61.2% specificity 80.8%) in women respectively. The odds ratio of the risk of metabolic syndrome was dramatically increased with the abdominal visceral fat thickness level over 6 cm in men and 5 cm in women. The visceral fat thickness using ultrasonography was significantly

  9. Ultrasound-based measurement of liquid-layer thickness: A novel time-domain approach

    Science.gov (United States)

    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.

  10. Assessment of the effect of bone density and soft tissue thickness on phantom measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Hye; Shim, Dong-Oh [Asan Medical Center, Seoul (Korea, Republic of); Dong, Kyung-Rae [Gwangju Health College University, Gwangju (Korea, Republic of); Chosun University, Gwangju (Korea, Republic of); Kim, Ho-Sung [Asan Medical Center, Seoul (Korea, Republic of); Chosun University, Gwangju (Korea, Republic of); Kweon, Dae-Cheol [Shin Heung College University, Uijeongbu (Korea, Republic of); Goo, Eun-Hoe [Seoul National University Hospital, Seoul (Korea, Republic of); Soonchunhyang University, Asan (Korea, Republic of); Chung, Woon-Kwan [Chosun University, Gwangju (Korea, Republic of)

    2010-11-15

    This study examined whether there would be a difference in bone density through a phantom test because of the effect of the thickness of the soft tissue on the bone density measured by using dual energy X-ray absorptiometry (DXA). Three scan modes were used: standard, thin and thick modes correspondly to a normal, an underweight and an overweight patient, respectively. Also, the three phantoms used were the Lunar aluminum spine phantom (ASP), the Hologic spine phantom (HSP), and the European spine phantom (ESP). Three acrylic plates of different thicknesses were used, and a water bath was used as the tissue equivalent material for the soft tissue. The ASP, HSP and ESP were measured 20 times without repositioning. In addition, measurements were carried out three times with the HSP and the ESP covered by an acrylic plate. In regard to controlling the depth of the water, the bone density was measured in the standard mode, where the depth of the water was adjusted using the ASP only and was then determined based on the judgment of the investigators. To confirm the accuracy of the mode selection, we measured the dependence of the bone density of the phantom on the depth of the water. The percentage coefficients of variation (CV%) of the bone mineral density (BMD) in the ASP, HSP and ESP were measured to be 0.17%, 0.45%, and 0.95%, respectively. When the soft tissue thickness was increased, the CV% of the BMD in the ASP, HSP and ESP were 0.65%, 2.24%, and 0.79%, respectively. A correlation analysis also revealed a significant positive correlation between the soft tissue thickness and the bone density (ASP: r{sup 2} = .926, HSP: r{sup 2} = .899). In contrast, a generalized phantom, ESP, showed a significant negative correlation between the tissue thickness and the bone density, which was different from those for the other two phantoms (ESP: r{sup 2} = -.733). After assessing the scan mode and the soft tissue thickness, the mean bone densities in the standard and the thick

  11. Thermal lens measurements in Yb-doped YAG, LuAG, Lu2O3, Sc2O3 ceramic lasers

    International Nuclear Information System (INIS)

    Pirri, A; Toci, G; Vannini, M; Ciofini, M; Lapucci, A; Gizzi, L A; Labate, L; Esposito, L; Hostaša, J

    2014-01-01

    we report the last experimental results obtained measuring the thermal lens effect in Yb(1at.%):Lu 2 O 3 , Yb(1at.%):Sc 3 O 3 , Yb(10at.%):LuAG and Yb(10at.%):YAG ceramics. The experimental set-up apparatus using a Shack-Hartmann wavefront sensor allows the comparison of the thermal lens obtained under lasing and non lasing conditions, in order to highlight differences in the thermal loading.

  12. Measurement of Choroidal Perfusion and Thickness Following Systemic Sildenafil (Viagra®)

    Science.gov (United States)

    Kim, David Y.; Silverman, Ronald H.; Chan, R.V. Paul; Khanifar, Aziz A.; Rondeau, Mark; Lloyd, Harriet; Schlegel, Peter; Coleman, D. Jackson

    2011-01-01

    Objective To demonstrate anatomic and physiologic changes in the human choroid following systemic sildenafil citrate (ViagraR) using enhanced depth imaging spectral domain-optical coherence tomography (EDI-OCT) and swept-scan high frequency digital ultrasound. Methods Seven healthy male subjects (mean age 32.7 years) were evaluated at baseline and two hours after ingesting 50 mg of sildenafil. Swept-scan high frequency digital ultrasound and EDI-OCT were utilized to measure choroidal perfusion and thickness, respectively. Results were read by masked observers. The Wilcoxon signed-rank test and t-test were used to analyze differences in choroidal flow and thickness at baseline and two hours after ingestion of sildenafil. Results Two hours following sildenafil, increased choroidal perfusion was observed in 11 of 12 eyes measured by swept-scan high frequency digital ultrasound. The mean increase was 3.46 (±2.00) times baseline with a range of 0.47 to 7.80 times baseline (p=0.004). Increased choroidal thickness was observed in 12 of 12 eyes measured with EDI-OCT. The average choroidal thickness increased by 11.6% temporal to the fovea, 9.3% nasal to the fovea, and 10.7% underneath the fovea (p<0.001 for all values). Conclusions Choroidal perfusion and thickness both increase in response to systemic sildenafil. These changes could secondarily affect retinal function, explain previously reported clinical symptoms, and potentially be a useful adjunct for treatment of ocular diseases that would benefit from increased choroidal blood flow. PMID:22974308

  13. Terahertz thickness measurements for real industrial applications: from automotive paints to aerospace industry (Conference Presentation)

    Science.gov (United States)

    Krimi, Soufiene; Beigang, René

    2017-02-01

    In this contribution, we present a highly accurate approach for real-time thickness measurements of multilayered coatings using terahertz time domain spectroscopy in reflection geometry. The proposed approach combines the benefits of a model-based material parameters extraction method to calibrate the specimen under test, a generalized modeling method to simulate the terahertz radiation behavior within arbitrary thin films, and the robustness of a powerful evolutionary optimization algorithm to increase the sensitivity and the precision of the minimum thickness measurement limit. Furthermore, a novel self-calibration model is introduced, which takes into consideration the real industrial challenges such as the effect of wet-on-wet spray in the car painting process and the influence of the spraying conditions and the sintering process on ceramic thermal barrier coatings (TBCs) in aircraft industry. In addition, the developed approach enables for some applications the simultaneous determination of the complex refractive index and the coating thickness. Hence, a pre-calibration of the specimen under test is not required for such cases. Due to the high robustness of the self-calibration method and the genetic optimization algorithms, the approach has been successfully applied to resolve individual layer thicknesses within multi-layered coated samples down to less than 10 µm. The regression method can be applied in time-domain, frequency-domain or in both the time and frequency-domain simultaneously. The data evaluation uses general-purpose computing on graphics processing units and thanks to the developed highly parallelized algorithm lasts less than 300 ms. Thus, industrial requirements for fast thickness measurements with an "every-second-cycle" can be fulfilled.

  14. Ultrasonographic evaluation of reproductive tract measures and fat thickness traits in pre-pubertal Nellore heifers

    Directory of Open Access Journals (Sweden)

    Fabio Morato Monteiro

    2012-02-01

    Full Text Available The aim of this study was to evaluate the relationship between reproductive tract and fat thickness measures obtained by ultrasound in prepubertal Nellore heifers. A total of 128 Nellore heifers born in 2006 and 2007 were submitted to ultrasound evaluations (13, 16, 19 and 22 months of age of reproductive tract measures and fat thickness traits. These animals were from a selection experiment (NeC: control line, and NeS: selection line for yearling weight started in 1981. Mean values of ovary area, height of the right uterine horn (HU, maximum follicular diameter (FOL, backfat thickness (BF, rump fat thickness (RF, and body condition score were analyzed. Repeated records were modeled using the PROC MIXED procedure (SAS, fitting a model that included the selection line, year of birth, measurement as fixed effects, and interactions. Body weight differed between the selected (281.48 kg and control (210.51 kg lines. Only the least square means of FOL were lower in the NeC line compared to the NeS line (P < 0.05, although the difference in mean HU between the two lines was of only borderline significance (P = 0.06. The rate of growth for the three reproductive traits was similar in the two lines. Simple and residual correlations between the reproductive and subcutaneous fat traits ranged from low to medium. The highest correlations were observed between HU and RF (Pearson correlation = 0.71 and residual correlation = 0.34. The current results are consistent with the literature, indicating that fat thickness traits are not good predictors of prepubertal reproductive traits in heifers. Further studies are necessary to clarify the relationship between reproduction and body fat in Nellore heifers.

  15. Macular choroidal thickness in normal Egyptians measured by swept source optical coherence tomography.

    Science.gov (United States)

    Moussa, Magdy; Sabry, Dalia; Soliman, Wael

    2016-08-05

    To provide a normal database of choroidal thickness (CT) in nine Early Treatment Diabetes Retinopathy Study (ETDRS) subfields in Egypt using deep-range imaging swept source optical coherence tomography (DRI SS OCT). This study included a total of 129 eyes of 71 normal Egyptian subjects, comprising 63 males and 66 females. The mean age was 36.85 ± 14.22 years (range, 16-67 years). The mean axial length was 23.84 ± 0.78 mm. CT was measured in nine subfields as defined by the ETDRS-style grid using a DRI SS OCT, and line measurements of subfoveal choroidal thicknesses (SFCT) were also performed. Mean SFCT was 300.87 ± 72.256 μm for ring measurements and 319.72 ± 76.45 μm for line measurements (P = 0.04). CT was higher in the superior and temporal quadrants than the inferior and nasal quadrants. A negative correlation between subfoveal choroidal thickness and age was detected in all regions (P < 0.001) except the nasal quadrant. A negative correlation between the SFCT and axial length was also detected (P < 0.001). Males tended to have a thicker choroid than females; however, the difference was not significant. DRI SS OCT provides a topographic map of choroidal thickness with an ETDRS layout. This study establishes, for the first time, a normal database for CT in the Egyptian population. Age and axial length were associated with choroidal parameters in healthy subjects. Line measurements of the SFCT differed significantly from SFCT ring measurements, so it is recommended that each method be compared independently.

  16. Measurement of nonlinear optical refraction of composite material based on sapphire with silver by Kerr-lens autocorrelation method.

    Science.gov (United States)

    Yu, Xiang-xiang; Wang, Yu-hua

    2014-01-13

    Silver nanoparticles synthesized in a synthetic sapphire matrix were fabricated by ion implantation using the metal vapor vacuum arc ion source. The optical absorption spectrum of the Ag: Al2O3 composite material has been measured. The analysis of the supercontinuum spectrum displayed the nonlinear refractive property of this kind of sample. Nonlinear optical refraction index was identified at 800 nm excitation using the Kerr-lens autocorrelation (KLAC) technique. The spectrum showed that the material possessed self-defocusing property (n(2) = -1.1 × 10(-15) cm(2)W). The mechanism of nonlinear refraction has been discussed.

  17. Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.

    Science.gov (United States)

    Henkel, S; Beyrau, F; Hardalupas, Y; Taylor, A M K P

    2016-02-08

    This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated.

  18. Chest wall thickness measurements and the dosimetric implications for male workers in the uranium industry

    International Nuclear Information System (INIS)

    Kramer, Gary H.; Hauck, Barry M.; Allen, Steve A.

    2000-01-01

    The Human Monitoring Laboratory has measured the chest wall thickness and adipose mass fraction of a group of workers at three Canadian uranium refinery, conversion plant, and fuel fabrication sites using ultrasound. A site specific biometric equation has been developed for these workers, who seem to be somewhat larger than other workers reported in the literature. The average chest wall thickness of the seated persons measured at the uranium conversion plant and refinery was about 3.8 cm, and at the fuel fabrication facility was 3.4 cm. These values are not statistically different. Persons measured in a seated geometry had a thinner chest wall thickness than persons measured in a supine geometry - the decrease was in the range of 0.3 cm to 0.5 cm. It follows that a seated geometry will give a lower MDA (or decision level) than a supine geometry. Chest wall thickness is a very important modifier for lung counting efficiency and this data has been put into the perspective of the impending Canadian dose limits that will reduce the limit of occupationally exposed workers to essentially 20 mSv per year. Natural uranium must be measured based on the 235 U emissions at these type of facilities. The refining and conversion process removes 234 Th and the equilibrium is disturbed. This is unfortunate as the MDA values for this nuclide are approximately a factor of three lower than the values quoted below. The sensitivity of the germanium and phoswich based lung counting system has been compared. Achievable MDA's (30 minute counting time) with a four-phoswich-detector array lie in the range of 4.7 mg to 13.5 mg of natural uranium based on the 235 U emissions over a range of chest wall thicknesses of 1.6 cm to 6.0 cm. The average achievable MDA is about 8.5 mg which can be reduced to about 6.2 mg by doubling the counting time. Similarly, MDA's (30 minute counting time) obtainable with a germanium lung counting system will lie in the range of 3 mg to 28 mg of natural uranium

  19. Residual stress measurements in thick structural weldments by means of neutron diffraction

    International Nuclear Information System (INIS)

    Ohms, C.; Youtsos, A.G.; Idsert, P. v.d.; Timke, T.

    2000-01-01

    Welding residual stresses in large structural components are a major concern with respect to their performance and lifetime. In large structures reasonable thermal stress relief treatment is usually impossible due to the component size. On the other hand, prediction of welding stresses by numerical modelling has not yet proven to be generally reliable, while the experimental determination of such stresses remains a demanding task. At the high flux reactor (HFR), Petten, a new residual stress diffractometer has been installed recently capable of handling of components up to 1000 kg - the large component neutron diffraction facility (LCNDF). It has facilitated residual stress measurements in two large welded components, of which results are presented here. The first component represents a bi-metallic weld in form of a pipe of 25 mm wall thickness. Three dimensional measurements of residual stress are discussed in detail. The second specimen is a 66 mm wall thickness austenitic steel nuclear piping weld. Results on relief of strain within the weld through post weld heat treatment (PWHT) are presented. Additionally results obtained earlier at former CRNL (CAN) on a section of a thick nuclear piping weld are presented in order to illustrate the variation in the reference lattice parameter trough the weld and the heat affected zone (HAZ). These results clearly show the necessity to determine the reference parameters for each location in all measurement directions by means of measurements in small coupons free of macro-stresses. (orig.)

  20. Reliability of sonographic muscle thickness measurements of the thenar and hypothenar muscles.

    Science.gov (United States)

    Misirlioglu, Tugce Ozekli; Ozyemisci Taskiran, Ozden

    2018-01-01

    Introduction This study was undertaken to assess the intra- and interrater reliability of sonographic thickness measurements of the thenar and hypothenar muscles. The thickness of the thenar and hypothenar muscles of both hands of 15 volunteers (7 male, 8 female) were evaluated with a 4-13-MHz linear probe by 2 examiners who were blinded to each other's measurements. Interrater reliability was then evaluated. To assess intrarater reliability, the first examiner also performed a second measurement after an interval of at least 1 day. Mean age of the subjects was 31.1 ± 9.0 years. Test-retest reliability showed excellent intrarater reliability (intraclass correlation coefficient range: 0.889-0.963) and substantial to excellent results for interrater reliability (intraclass correlation coefficient range: 0.692-0.937). We found that ultrasound is a reliable method for thickness measurements of the thenar and hypothenar muscles. Muscle Nerve 57: E14-E17, 2018. © 2017 Wiley Periodicals, Inc.

  1. A reliable control system for measurement on film thickness in copper chemical mechanical planarization system

    Science.gov (United States)

    Li, Hongkai; Qu, Zilian; Zhao, Qian; Tian, Fangxin; Zhao, Dewen; Meng, Yonggang; Lu, Xinchun

    2013-12-01

    In recent years, a variety of film thickness measurement techniques for copper chemical mechanical planarization (CMP) are subsequently proposed. In this paper, the eddy-current technique is used. In the control system of the CMP tool developed in the State Key Laboratory of Tribology, there are in situ module and off-line module for measurement subsystem. The in situ module can get the thickness of copper film on wafer surface in real time, and accurately judge when the CMP process should stop. This is called end-point detection. The off-line module is used for multi-points measurement after CMP process, in order to know the thickness of remained copper film. The whole control system is structured with two levels, and the physical connection between the upper and the lower is achieved by the industrial Ethernet. The process flow includes calibration and measurement, and there are different algorithms for two modules. In the process of software development, C++ is chosen as the programming language, in combination with Qt OpenSource to design two modules' GUI and OPC technology to implement the communication between the two levels. In addition, the drawing function is developed relying on Matlab, enriching the software functions of the off-line module. The result shows that the control system is running stably after repeated tests and practical operations for a long time.

  2. Development and beam-shape analysis of an integrated fiber-optic confocal probe for high-precision central thickness measurement of small-radius lenses.

    Science.gov (United States)

    Sutapun, Boonsong; Somboonkaew, Armote; Amarit, Ratthasart; Chanhorm, Sataporn

    2015-04-13

    This work describes a new design of a fiber-optic confocal probe suitable for measuring the central thicknesses of small-radius optical lenses or similar objects. The proposed confocal probe utilizes an integrated camera that functions as a shape-encoded position-sensing device. The confocal signal for thickness measurement and beam-shape data for off-axis measurement can be simultaneously acquired using the proposed probe. Placing the probe's focal point off-center relative to a sample's vertex produces a non-circular image at the camera's image plane that closely resembles an ellipse for small displacements. We were able to precisely position the confocal probe's focal point relative to the vertex point of a ball lens with a radius of 2.5 mm, with a lateral resolution of 1.2 µm. The reflected beam shape based on partial blocking by an aperture was analyzed and verified experimentally. The proposed confocal probe offers a low-cost, high-precision technique, an alternative to a high-cost three-dimensional surface profiler, for tight quality control of small optical lenses during the manufacturing process.

  3. Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

    Directory of Open Access Journals (Sweden)

    Boonsong Sutapun

    2015-04-01

    Full Text Available This work describes a new design of a fiber-optic confocal probe suitable for measuring the central thicknesses of small-radius optical lenses or similar objects. The proposed confocal probe utilizes an integrated camera that functions as a shape-encoded position-sensing device. The confocal signal for thickness measurement and beam-shape data for off-axis measurement can be simultaneously acquired using the proposed probe. Placing the probe’s focal point off-center relative to a sample’s vertex produces a non-circular image at the camera’s image plane that closely resembles an ellipse for small displacements. We were able to precisely position the confocal probe’s focal point relative to the vertex point of a ball lens with a radius of 2.5 mm, with a lateral resolution of 1.2 µm. The reflected beam shape based on partial blocking by an aperture was analyzed and verified experimentally. The proposed confocal probe offers a low-cost, high-precision technique, an alternative to a high-cost three-dimensional surface profiler, for tight quality control of small optical lenses during the manufacturing process.

  4. Highly accurate thickness measurement of multi-layered automotive paints using terahertz technology

    Science.gov (United States)

    Krimi, Soufiene; Klier, Jens; Jonuscheit, Joachim; von Freymann, Georg; Urbansky, Ralph; Beigang, René

    2016-07-01

    In this contribution, we present a highly accurate approach for thickness measurements of multi-layered automotive paints using terahertz time domain spectroscopy in reflection geometry. The proposed method combines the benefits of a model-based material parameters extraction method to calibrate the paint coatings, a generalized Rouard's method to simulate the terahertz radiation behavior within arbitrary thin films, and the robustness of a powerful evolutionary optimization algorithm to increase the sensitivity of the minimum thickness measurement limit. Within the framework of this work, a self-calibration model is introduced, which takes into consideration the real industrial challenges such as the effect of wet-on-wet spray in the painting process.

  5. Highly accurate thickness measurement of multi-layered automotive paints using terahertz technology

    International Nuclear Information System (INIS)

    Krimi, Soufiene; Beigang, René; Klier, Jens; Jonuscheit, Joachim; Freymann, Georg von; Urbansky, Ralph

    2016-01-01

    In this contribution, we present a highly accurate approach for thickness measurements of multi-layered automotive paints using terahertz time domain spectroscopy in reflection geometry. The proposed method combines the benefits of a model-based material parameters extraction method to calibrate the paint coatings, a generalized Rouard's method to simulate the terahertz radiation behavior within arbitrary thin films, and the robustness of a powerful evolutionary optimization algorithm to increase the sensitivity of the minimum thickness measurement limit. Within the framework of this work, a self-calibration model is introduced, which takes into consideration the real industrial challenges such as the effect of wet-on-wet spray in the painting process.

  6. Neutron diffraction measurements of residual stresses in a 50 mm thick weld

    International Nuclear Information System (INIS)

    Woo, Wanchuck; Em, Vyacheslav; Mikula, Pavel; An, Gyu-Baek; Seong, Baek-Seok

    2011-01-01

    Research highlights: → Determined residual stresses through the thickness of the 50 mm thick weld. → Two-dimensional mapping of the longitudinal stress. Observed significant stresses along the heat-affected zone. → Measured the maximum stress of 460 MPa at 40 mm below from the top surface. - Abstract: Residual stresses were determined through the thickness of a 50 mm thick ferrite steel weld plate using neutron diffraction. Whereas the limiting penetration depth for iron-based alloys is about 25 mm in the most typical neutron diffractometers, we significantly enhanced the penetration depth up to 50 mm with 2 mm spatial resolution by using the neutron wavelength of 2.39 A. The selected wavelength minimizes the total neutron cross-section and beam attenuation, thereby, maximizes the neutron fluxes at depth. Two-dimensional mapping of the residual stresses shows that significant amounts of the tensile longitudinal stresses (over 90% of yield strength) were developed along the heat-affected zone of the weld.

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... an ophthalmologist — an eye medical doctor — who will measure each eye and talk to you about proper ...

  8. Measurement of fibrous cap thickness in atherosclerotic plaques by spatiotemporal analysis of laser speckle images

    Science.gov (United States)

    Nadkarni, Seemantini K.; Bilenca, Alberto; Bouma, Brett E.; Tearney, Guillermo J.

    2010-01-01

    Necrotic-core fibroatheromas (NCFA) with thin, mechanically weak fibrous caps overlying lipid cores comprise the majority of plaques that rupture and cause acute myocardial infarction. Laser speckle imaging (LSI) has been recently demonstrated to enable atherosclerotic plaque characterization with high accuracy. We investigate spatio-temporal analysis of LSI data, in conjunction with diffusion theory and Monte Carlo modeling of light transport, to estimate fibrous cap thickness in NCFAs. Time-varying laser speckle images of 20 NCFAs are selected for analysis. Spatio-temporal intensity fluctuations are analyzed by exponential fitting of the windowed normalized cross-correlation of sequential laser speckle patterns to obtain the speckle decorrelation time constant, τ(ρ), as a function of distance ρ from the source entry location. The distance, ρ′, at which τ(ρ) dropped to 65% of its maximum value is recorded. Diffusion theory and Monte Carlo models are utilized to estimate the maximum photon penetration depth, zmax(ρ′), for a distance equal to ρ′, measured from LSI. Measurements of zmax(ρ′) correlate well with histological measurements of fibrous cap thickness (R=0.78, p<0.0001), and paired t-tests show no significant difference between the groups (p=0.4). These results demonstrate that spatio-temporal LSI may allow the estimation of fibrous cap thickness in NCFAs, which is an important predictor of plaque Stability. PMID:16674181

  9. Residual stress measurements in a thick, dissimilar aluminum alloy friction stir weld

    International Nuclear Information System (INIS)

    Prime, Michael B.; Gnaeupel-Herold, Thomas; Baumann, John A.; Lederich, Richard J.; Bowden, David M.; Sebring, Robert J.

    2006-01-01

    Plates (25.4 mm thick) of aluminum alloys 7050-T7451 and 2024-T351 were joined in a butt joint by friction stir welding (FSW). A 54 mm long test specimen was removed from the parent plate, and cross-sectional maps of residual stresses were measured using neutron diffraction and the contour method. The stresses in the test specimen peaked at only about 32 MPa and had the conventional 'M' profile with tensile stress peaks in the heat-affected zone outside the weld. The asymmetric stress distribution is discussed relative to the FSW process and the regions of highest thermal gradients. The general agreement between the two measurement techniques validated the ability of each technique to measure the low-magnitude stresses, less than 0.05% of the elastic modulus. Subtle differences between the two were attributed to spatial variations in the unstressed lattice spacing (d 0 ) and also intergranular strains affecting the neutron results. The FSW stresses prior to relaxation from removal of the test specimen were estimated to have been about 43 MPa, demonstrating the ability of FSW to produce low-stress welds in even fairly thick sections. To avoid the estimated 25% stress relaxation from removing the test specimen, the specimen would have had to be quite long because the St. Venant's characteristic distance in this case was more related to the transverse dimensions of the specimen than to the plate thickness

  10. Semi-automated Digital Imaging and Processing System for Measuring Lake Ice Thickness

    Science.gov (United States)

    Singh, Preetpal

    Canada is home to thousands of freshwater lakes and rivers. Apart from being sources of infinite natural beauty, rivers and lakes are an important source of water, food and transportation. The northern hemisphere of Canada experiences extreme cold temperatures in the winter resulting in a freeze up of regional lakes and rivers. Frozen lakes and rivers tend to offer unique opportunities in terms of wildlife harvesting and winter transportation. Ice roads built on frozen rivers and lakes are vital supply lines for industrial operations in the remote north. Monitoring the ice freeze-up and break-up dates annually can help predict regional climatic changes. Lake ice impacts a variety of physical, ecological and economic processes. The construction and maintenance of a winter road can cost millions of dollars annually. A good understanding of ice mechanics is required to build and deem an ice road safe. A crucial factor in calculating load bearing capacity of ice sheets is the thickness of ice. Construction costs are mainly attributed to producing and maintaining a specific thickness and density of ice that can support different loads. Climate change is leading to warmer temperatures causing the ice to thin faster. At a certain point, a winter road may not be thick enough to support travel and transportation. There is considerable interest in monitoring winter road conditions given the high construction and maintenance costs involved. Remote sensing technologies such as Synthetic Aperture Radar have been successfully utilized to study the extent of ice covers and record freeze-up and break-up dates of ice on lakes and rivers across the north. Ice road builders often used Ultrasound equipment to measure ice thickness. However, an automated monitoring system, based on machine vision and image processing technology, which can measure ice thickness on lakes has not been thought of. Machine vision and image processing techniques have successfully been used in manufacturing

  11. Human Chorioretinal Layer Thicknesses Measured in Macula-wide, High-Resolution Histologic Sections

    Science.gov (United States)

    Messinger, Jeffrey D.; Sloan, Kenneth R.; Mitra, Arnab; McGwin, Gerald; Spaide, Richard F.

    2011-01-01

    Purpose. To provide a comprehensive description of chorioretinal layer thicknesses in the normal human macula, including two-layer pairs that can produce a combined signal in some optical coherence tomography (OCT) devices (ganglion cell [GCL] and inner plexiform [IPL] layers and outer plexiform [OPL] and outer nuclear [ONL] layers). Methods. In 0.8-μm-thick, macula-wide sections through the foveola of 18 donors (age range, 40–92 years), 21 layers were measured at 25 locations by a trained observer and validated by a second observer. Tissue volume changes were assessed by comparing total retinal thickness in ex vivo OCT and in sections. Results. Median tissue shrinkage was 14.5% overall and 29% in the fovea. Histologic laminar boundaries resembled those in SD-OCT scans, but the shapes of the foveolar OPL and ONL differed. Histologic GCL, IPL, and OPLHenle were thickest at 0.8. to 1, 1.5, and 0.4 mm eccentricity, respectively. ONL was thickest in an inward bulge at the foveal center. At 1 mm eccentricity, GCL, INL, and OPLHenle represented 17.3% to 21.1%, 18.0% to 18.5%, and 14.2% to 16.6% of total retinal thickness, respectively. In donors ≥70 years of age, the RPE and choroid were 17.1% and 29.6% thinner and OPLHenle was 20.8% thicker than in donors macula were generated. Newer OCT systems can separate GCL from IPL and OPLHenle from ONL, with good agreement for the proportion of retinal thickness occupied by OPLHenle in OCT and histology. The thickening of OPLHenle in older eyes may reflect Müller cell hypertrophy associated with rod loss. PMID:21421869

  12. Eye lens dosimetry in interventional cardiology: Results of staff dose measurements and link to patient dose levels

    International Nuclear Information System (INIS)

    Antic, V.; Ciraj-Bjelac, O.; Rehani, M.; Aleksandric, S.; Arandjic, D.; Ostojic, M.

    2013-01-01

    Workers involved in interventional cardiology procedures receive high eye lens dose if protection is not used. Currently, there is no suitable method for routine use for the measurement of eye dose. Since most angiography machines are equipped with suitable patient dosemeters, deriving factors linking staff eye doses to the patient doses can be helpful. In this study the patient kerma-area product, cumulative dose at an interventional reference point and eye dose in terms of Hp(3) of the cardiologists, nurses and radiographers for interventional cardiology procedures have been measured. Correlations between the patient dose and the staff eye dose were obtained. The mean eye dose was 121 mSv for the first operator, 33 mSv for the second operator/nurse and 12 mSv for radiographer. Normalised eye lens doses per unit kerma-area product were 0.94 mSv Gy -1 cm -2 for the first operator, 0.33 mSv Gy -1 cm -2 for the second operator/nurse and 0.16 mSv Gy -1 cm -2 for radiographers. Statistical analysis indicated that there is a weak but significant (p < 0.01) correlation between the eye dose and the kerma-area product for all three staff categories. These values are based on a local practice and may provide useful reference for other studies for validation and for wider utilisation in assessing the eye dose using patient dose values. (authors)

  13. Comparison of two retinal nerve fibre layer thickness measurement patterns of RTvue optical coherence tomography.

    Science.gov (United States)

    Li, Shuning; Wang, Xiaozhen; Wu, Gewei; Fu, Jing; Li, Songfeng; Wan, Xiuhua; Wang, Ningli

    2011-04-01

    To evaluate the agreement and repeatability between operator-dependent centring and automatic centring retinal nerve fibre layer thickness measurement patterns (RNFL3.45 and NHM4) of RTvue optical coherence tomography in normal and glaucomatous eyes.   Cross-sectional observational study. A total of 153 eyes from 149 normal subjects and subjects with glaucoma were analysed.   The retinal nerve fibre layer thickness was measured using RNFL3.45 and NHM4 three times on the same day to determine the repeatability and agreement between the two scan patterns. Student's paired t-testing, intra-class correlation coefficient, coefficient of variation, test-retest viability, Pearson's correlation coefficient and Bland-Altman analysis of retinal nerve fibre layer thickness measurements. The difference between RNFL3.45 and NHM4 measurements was statistically significant by paired t-testing (P=0.003) only in severe glaucoma group. The Pearson's correlation test showed a high degree of correlation of the mean retinal nerve fibre layer thickness (r=0.949). Bland-Altman plots showed that the differences between RNFL3.45 and NHM4 were smaller at thicker retinal nerve fibre layer values, but larger at thinner retinal nerve fibre layer values. The intra-class correlation coefficient for RNFL3.45 (and lower 95% confidence interval) in normal and glaucomatous eyes was 0.990 (0.985 confidence interval) and 0.997 (0.995 confidence interval), respectively. The intra-class correlation coefficient for NHM4 in normal and glaucomatous eyes was 0.989 (0.983 confidence interval) and 0.995 (0.992 confidence interval), respectively. The test-retest variability for RNFL3.45 and NHM4 ranged from 3.98 to 9.75µm in normal eyes, and from 4.10 to 13.34µm in glaucomatous eyes. Measurements of retinal nerve fibre layer thickness by RNFL3.45 and NHM4 are in good agreement. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of

  14. Ultrasonic thickness structural health monitoring photoelastic visualization and measurement accuracy for internal pipe corrosion

    Science.gov (United States)

    Eason, Thomas J.; Bond, Leonard J.; Lozev, Mark G.

    2015-03-01

    Oil refinery production of fuels is becoming more challenging as a result of the changing world supply of crude oil towards properties of higher density, higher sulfur concentration, and higher acidity. One such production challenge is an increased risk of naphthenic acid corrosion that can result in various surface degradation profiles of uniform corrosion, non-uniform corrosion, and localized pitting in piping systems at temperatures between 150°C and 400°C. The irregular internal surface topology and high external surface temperature leads to a challenging in-service monitoring application for accurate pipe wall thickness measurements. Improved measurement technology is needed to continuously profile the local minimum thickness points of a non-uniformly corroding surface. The measurement accuracy and precision must be sufficient to provide a better understanding of the integrity risk associated with refining crude oils of higher acid concentration. This paper discusses potential technologies for measuring localized internal corrosion in high temperature steel piping and describes the approach under investigation to apply flexible ultrasonic thin-film piezoelectric transducer arrays fabricated by the sol-gel manufacturing process. Next, the elastic wave beam profile of a sol-gel transducer is characterized via photoelastic visualization. Finally, the variables that impact measurement accuracy and precision are discussed and a maximum likelihood statistical method is presented and demonstrated to quantify the measurement accuracy and precision of various time-of-flight thickness calculation methods in an ideal environment. The statistical method results in confidence values analogous to the a90 and a90/95 terminology used in Probability-of-Detection (POD) assessments.

  15. Comparisons of Soft Tissue Thickness Measurements in Adult Patients With Various Vertical Patterns

    Directory of Open Access Journals (Sweden)

    Neslihan Seyhan Cezairli

    2017-08-01

    Full Text Available Objective: The purposes of this study were to evaluate to study soft tissue facial profile among the different vertical patterns using the Holdaway analysis and the soft tissue thickness measurements. Materials and Methods: The study sample consisted of 90 patients divided into 3 groups: low angle group (30 patients; mean age, 20.38±3.76 years, normal angle group (30 patients; mean age, 19.36±2.83 years and high angle group (30 patients; mean age, 19.44±2.14 years. The study sample, comprised a total of 90 patients (54 women and 36 men divided into low-angle, normal-angle and high angle groups based on vertical growth pattern using the SN/GoGn angle (high-angle group >37°; low-angle group <27°; and control group or normal angle group 27-37°. Facial soft-tissue thickness and Holdaway measurements were analyzed on each radiograph with Image J programme. One-way analysis of variance and post-hoc test (Tukey were used to compare Holdaway measurements and soft tissue thicknesses among the three groups. Results: Significant differences among vertical patterns were observed for the ‘gnathion’, ‘menton’, ‘stomion’ and ‘inferior sulcus to H line’ when both genders were combined. These measurements were thinner in the high-angle group. Significant differences among vertical patterns were observed for ‘gnathion’ and ‘lower lip to H line’ in women; for ‘stomion’ and ‘nose prominence’ in men when examined separately. Conclusion: Facial soft tissue measurements except some for in high angle group were thinner than in low angle group. All soft tissue measurements were greater except for gnathion in low angle group in men than in women.

  16. Airborne thickness and freeboard measurements over the McMurdo Ice Shelf, Antarctica, and implications for ice density

    Science.gov (United States)

    Rack, Wolfgang; Haas, Christian; Langhorne, Pat J.

    2013-11-01

    We present airborne measurements to investigate the thickness of the western McMurdo Ice Shelf in the western Ross Sea, Antarctica. Because of basal accretion of marine ice and brine intrusions conventional radar systems are limited in detecting the ice thickness in this area. In November 2009, we used a helicopter-borne laser and electromagnetic induction sounder (EM bird) to measure several thickness and freeboard profiles across the ice shelf. The maximum electromagnetically detectable ice thickness was about 55 m. Assuming hydrostatic equilibrium, the simultaneous measurement of ice freeboard and thickness was used to derive bulk ice densities ranging from 800 to 975 kg m-3. Densities higher than those of pure ice can be largely explained by the abundance of sediments accumulated at the surface and present within the ice shelf, and are likely to a smaller extent related to the overestimation of ice thickness by the electromagnetic induction measurement related to the presence of a subice platelet layer. The equivalent thickness of debris at a density of 2800 kg m-3 is found to be up to about 2 m thick. A subice platelet layer below the ice shelf, similar to what is observed in front of the ice shelf below the sea ice, is likely to exist in areas of highest thickness. The thickness and density distribution reflects a picture of areas of basal freezing and supercooled Ice Shelf Water emerging from below the central ice shelf cavity into McMurdo Sound.

  17. Accelerated Changes in Cortical Thickness Measurements with Age in Military Service Members with Traumatic Brain Injury.

    Science.gov (United States)

    Savjani, Ricky R; Taylor, Brian A; Acion, Laura; Wilde, Elisabeth A; Jorge, Ricardo E

    2017-11-15

    Finding objective and quantifiable imaging markers of mild traumatic brain injury (TBI) has proven challenging, especially in the military population. Changes in cortical thickness after injury have been reported in animals and in humans, but it is unclear how these alterations manifest in the chronic phase, and it is difficult to characterize accurately with imaging. We used cortical thickness measures derived from Advanced Normalization Tools (ANTs) to predict a continuous demographic variable: age. We trained four different regression models (linear regression, support vector regression, Gaussian process regression, and random forests) to predict age from healthy control brains from publicly available datasets (n = 762). We then used these models to predict brain age in military Service Members with TBI (n = 92) and military Service Members without TBI (n = 34). Our results show that all four models overpredicted age in Service Members with TBI, and the predicted age difference was significantly greater compared with military controls. These data extend previous civilian findings and show that cortical thickness measures may reveal an association of accelerated changes over time with military TBI.

  18. Equations of bark thickness and volume profiles at different heights with easy-measurement variables

    Energy Technology Data Exchange (ETDEWEB)

    Cellini, J. M.; Galarza, M.; Burns, S. L.; Martinez-Pastur, G. J.; Lencinas, M. V.

    2012-11-01

    The objective of this work was to develop equations of thickness profile and bark volume at different heights with easy-measurement variables, taking as a study case Nothofagus pumilio forests, growing in different site qualities and growth phases in Southern Patagonia. Data was collected from 717 harvested trees. Three models were fitted using multiple, non-lineal regression and generalized linear model, by stepwise methodology, iteratively reweighted least squares method for maximum likelihood estimation and Marquardt algorithm. The dependent variables were diameter at 1.30 m height (DBH), relative height (RH) and growth phase (GP). The statistic evaluation was made through the adjusted determinant coefficient (r2-adj), standard error of the estimation (SEE), mean absolute error and residual analysis. All models presented good fitness with a significant correlation with the growth phase. A decrease in the thickness was observed when the relative height increase. Moreover, a bark coefficient was made to calculate volume with and without bark of individual trees, where significant differences according to site quality of the stands and DBH class of the trees were observed. It can be concluded that the prediction of bark thickness and bark coefficient is possible using DBH, height, site quality and growth phase, common and easy measurement variables used in forest inventories. (Author) 23 refs.

  19. High resolution thickness measurements of ultrathin Si:P monolayers using weak localization

    Science.gov (United States)

    Hagmann, Joseph A.; Wang, Xiqiao; Namboodiri, Pradeep; Wyrick, Jonathan; Murray, Roy; Stewart, M. D.; Silver, Richard M.; Richter, Curt A.

    2018-01-01

    The key building blocks for the fabrication of devices based on the deterministic placement of dopants in silicon using scanning tunneling microscopy (STM) hydrogen lithography are the formation of well-defined dopant delta-layers and the overgrowth of high quality crystalline Si. To develop these capabilities, it is of critical importance to quantify dopant movement in the sub-nanometer regime. To this end, we investigate Si:P delta-layer samples produced by fully exposing a Si surface to PH3 prior to Si encapsulation with dramatically different levels of dopant confinement. We examine the effect of delta layer confinement on the weak localization signal in parallel and perpendicular magnetic fields and extract the delta-layer thickness from fits to the Hikami-Larkin-Nagaoka equation. We find good agreement with secondary ion mass spectroscopy measurements and demonstrate the applicability of this method in the sub-nanometer thickness regime. Our analysis serves as detailed instruction for the determination of the conducting layer thickness of a Si:P delta-layer by means of a high-throughput, nondestructive electrical transport measurement.

  20. Scale Thickness Measurement of Steam Generator Tubing Using Eddy Current Signal of Bobbin Coil

    International Nuclear Information System (INIS)

    Kim, Chang Soo; Um, Ki Soo; Kim, Jae Dong

    2012-01-01

    Steam generator is one of the major components of nuclear power plant and steam generator tubes are the pressure boundary between primary and secondary side, which makes them critical for nuclear safety. As the operating time of nuclear power plant increases, not only damage mechanisms but also scaled deposits on steam generator tubes are known to be problematic causing tube support flow hole blockage and heat fouling. The ability to assess the extent and location of scaled deposits on tubes became essential for management and maintenance of steam generator and eddy current bobbin data can be utilized to measure thickness of scale on tubes. In this paper, tube reference standards with various thickness of scaled deposit has been set up to provide information about the overall deposit condition of steam generator tubes, providing essential tool for steam generator management and maintenance to predict and prevent future damages. Also, methodology to automatically measure scale thickness on tubes has been developed and applied to field data to estimate overall scale amount.

  1. [Implication of the measurement of central corneal thickness in management of glaucoma patients].

    Science.gov (United States)

    Zhang, Shun-hua; Zhao, Jia-liang

    2009-02-01

    Intraocular pressure (IOP) is a elementary data in diagnosis and therapy of glaucoma. Many studies have confirmed that most tonometry, including Goldmann applanation tonometry, are influenced by central corneal thickness (CCT) and CCT varies greatly among the general population. As a result, the measurement of CCT has a great implication in management of glaucoma. Further, CCT is confirmed a risk factor for progression from ocular hypertension to primary open angle glaucoma. The idea of that CCT may bear an inverse relation with the risk for developing glaucoma damage is in debating. Many specialists bring forward that CCT measurement should be one of the regular examinations in treatment of glaucoma patients.

  2. Corneo-scleral limbal changes following short-term soft contact lens wear.

    Science.gov (United States)

    Consejo, Alejandra; Bartuzel, Maciej M; Iskander, D Robert

    2017-10-01

    To assess whether short-term soft contact lens wear alters the anterior eye surface. Twenty-two neophyte subjects wore soft contact lenses for a period of five hours. Topography based corneo-scleral limbal radius estimates were derived from height measurements acquired with a corneo-scleral profilometer. Additionally, central corneal thickness (CCT), anterior chamber depth (ACD), corneal curvature radius (R) and white-to-white (WTW) diameter were acquired with an OCT-assisted biometer. Measurements were obtained without lens wear (baseline), immediately after lens removal following five hours of wear and three hours after lens removal. Short-term soft contact lens wear significantly modifies corneo-scleral limbal radius (mean±SD: 130±74μm, p contact lens wear. The increment in the limbal diameter could reach over 0.5mm but that alteration does not correspond to changes in WTW diameter and it was not observable to the examiner using a slit lamp. Assessing topographical limbus after contact lens wear could be a tool to optimize the selection of the contact lens, from the perspective of anterior eye surface changes. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  3. Retinal nerve fibre layer thickness measurements by optical coherence tomography in patients with sleep apnoea syndrome.

    Science.gov (United States)

    Sagiv, Oded; Fishelson-Arev, Tagil; Buckman, Gila; Mathalone, Nurit; Wolfson, Julia; Segev, Eitan; Peled, Ron; Lavi, Idit; Geyer, Orna

    2014-03-01

    The study aims to investigate whether retinal nerve fibre layer (RNFL) abnormalities can be detected in patients with obstructive sleep apnoea/hypopnoea syndrome with normally appearing optic disc. This is an observational case-control study. One hundred and eight consecutive patients with moderate or severe obstructive sleep apnoea/hypopnoea syndrome (OSAHS) as determined by overnight polysomnography and normal looking discs and 108 age-matched healthy controls were included in the study. All patients underwent RNFL examinations by optical coherence tomography using fast retinal nerve fibre layer thickness scan. The main outcome measure was RNFL thickness. Multivariate regression analysis results showed that the RNFL was thinner for a patient with OSAHS than that of a normal control in the average by 4.20 μm (P optic nerves will eventually lead to glaucoma. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  4. Measurement of thickness of thin films by the X-ray diffraction method

    International Nuclear Information System (INIS)

    Srinivasan, C.; Balasingh, C.; Singh, A.K.

    1979-07-01

    X-ray diffraction method can be used to measure the thickness of thin films (coatings). The principle and the experimental details of the x-ray diffraction methods are described. The intensities of the diffracted beams are derived assuming a random orientation of the crystallites in the diffracting medium. Consequently, the expressions are not valid when the sample has preferred orientation. To check the performance of the method, thicknesses of nickel deposits on mild steel plates were determined by the x-ray diffraction method and the results compared with those obtained by the weighing method and metallographic examination. The weighing method which gives an accuracy of +- 0.1 micron is taken as the standard. The x-ray diffraction methods and the metallographic examinations give values within +- 1 micron of the value obtained by the weighing method. (author)

  5. Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography.

    Science.gov (United States)

    Hirsch, J E

    2013-10-01

    We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Evaluation of lens dose from anterior electron beams: comparison of Pinnacle and Gafchromic EBT3 film.

    Science.gov (United States)

    Sonier, Marcus; Wronski, Matt; Yeboah, Collins

    2015-03-08

    Lens dose is a concern during the treatment of facial lesions with anterior electron beams. Lead shielding is routinely employed to reduce lens dose and minimize late complications. The purpose of this work is twofold: 1) to measure dose pro-files under large-area lead shielding at the lens depth for clinical electron energies via film dosimetry; and 2) to assess the accuracy of the Pinnacle treatment planning system in calculating doses under lead shields. First, to simulate the clinical geometry, EBT3 film and 4 cm wide lead shields were incorporated into a Solid Water phantom. With the lead shield inside the phantom, the film was positioned at a depth of 0.7 cm below the lead, while a variable thickness of solid water, simulating bolus, was placed on top. This geometry was reproduced in Pinnacle to calculate dose profiles using the pencil beam electron algorithm. The measured and calculated dose profiles were normalized to the central-axis dose maximum in a homogeneous phantom with no lead shielding. The resulting measured profiles, functions of bolus thickness and incident electron energy, can be used to estimate the lens dose under various clinical scenarios. These profiles showed a minimum lead margin of 0.5 cm beyond the lens boundary is required to shield the lens to ≤ 10% of the dose maximum. Comparisons with Pinnacle showed a consistent overestimation of dose under the lead shield with discrepancies of ~ 25% occur-ring near the shield edge. This discrepancy was found to increase with electron energy and bolus thickness and decrease with distance from the lead edge. Thus, the Pinnacle electron algorithm is not recommended for estimating lens dose in this situation. The film measurements, however, allow for a reasonable estimate of lens dose from electron beams and for clinicians to assess the lead margin required to reduce the lens dose to an acceptable level.

  7. The research of thickness measurement base on γ-ray compton backscattering

    International Nuclear Information System (INIS)

    Chen Xinnan; Wang Guobao; Chen Yannan

    2010-01-01

    The source and detector should be on the same side in many industrial cases, such as measurement of large scale pipes or steel plates and some large objects through which gamma ray can not transmit. Unlike the transmission method, the advantage of Compton backscattering is the flexible method of layout between source and detector. The research of Compton backscattering is very important to solve these special problems. This work describes a new method of layout between the source and the detector. Using the Monte Carol method several key factors which were associated with the measurement were also simulated, such as collimator dimension, the distance between the detector and the sample, source intensity, measured pieces. The result indicated this measurement method could entirely meet the requirement. The simulated result from Monte Carol was proved by the experiment. The experiments accord with the simulated result: the bigger the collimator diameter is, the bigger the counting rate received by detector is, the less the linear range is; For the organic glass, 5-8 mm is the best distance range between detector and samples. Different thickness associate with different distance and collimator dimension. These results provide a good technical base for research of thickness measurement based on Compton backscattering, offer a guide to practical application. (authors)

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

    Science.gov (United States)

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

    2008-12-22

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

  9. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  10. Choroidal thickness measurements with optical coherence tomography in branch retinal vein occlusion

    Directory of Open Access Journals (Sweden)

    Muge Coban-Karatas

    2016-05-01

    Full Text Available AIM: To evaluate central macular thickness (CMT and mean choroidal thickness (MCT in eyes with branch retinal vein occlusion (BRVO, before and after ranibizumab treatment using spectral domain-optical coherence tomography (SD-OCT. METHODS: Forty-two patients with unilateral BRVO and macular edema were included in this study. There were 25 men and 17 women. Using SD-OCT, choroidal thickness was measured at 500 µm intervals up to 1500 µm temporal and nasal to the fovea. MCT was calculated based on the average of the 7 locations. All the eyes with BRVO were treated with intravitreal ranibizumab (0.5 mg/0.05 mL. Comparisons between the BRVO and fellow eyes were analyzed using Mann-Whitney U test. Pre-injection and post-injection measurements were analyzed using Wilcoxon test and repeated measure analysis. RESULTS: At baseline, there was a significant difference between the BRVO and fellow eyes in MCT [BRVO eyes 245 (165-330 µm, fellow eyes 229 (157-327 µm] and CMT [BRVO eyes 463 (266-899 µm, fellow eyes 235 (148-378 µm (P=0.041, 0.0001, respectively]. Following treatment, CMT [295 (141-558 µm] and MCT [229 (157-329 µm] decreased significantly compared to the baseline measurements (P=0.001, 0.006, respectively. Also BCVA (logMAR improved significantly (P=0.0001 in the BRVO eyes following treatment. After treatment CMT [BRVO eyes 295 (141-558 µm, fellow eyes 234 (157-351 µm] and MCT [BRVO eyes 229 (157-329 µm, fellow eyes 233 (162-286 µm] values did not reveal any significant difference in BRVO eyes and fellow eyes (P=0.051, 0.824, respectively. CONCLUSION: In eyes with BRVO, CMT and MCT values are greater than the fellow eyes, and decrease significantly following ranibizumab injection.

  11. DAC Measurement of High-Pressure Yield Strength of Vanadium using In-Situ Thickness Determination

    Energy Technology Data Exchange (ETDEWEB)

    Klepeis, J P; Cynn, H; Evans, W J; Rudd, R E; Yang, L H; Liermann, H P; Yang, W

    2009-07-16

    The pressure-dependence of the quasi-static yield strength of vanadium in polycrystalline foils and powders has been measured up to 80 GPa at room temperature using an implementation of a non-hydrostatic diamond anvil cell technique [C. Meade and R. Jeanloz, J. Geophys. Res. 93, 3261 (1988)]. A new feature of this work is the use of an in-situ determination of the sample thickness. Following an initial increase in the strength with pressure, a decrease in the strength of vanadium was observed beginning at 40-50 GPa. We have measured the yield strength of vanadium up to 80 GPa under nonhydrostatic conditions. In this study, we used x-ray diffraction and absorption techniques to make in-situ measurements of the pressure gradient and the sample thickness. These measurements were used to evaluate the pressure-dependence of the material strength. We observed a decease in the yield strength of vanadium over the pressure range of 40-50 GPa. We propose that this change in the yieldstrength pressure-dependence is an indicator of the phase transition from bcc to rhombohedral.

  12. A comparison of two methods to measure choroidal thickness by enhanced depth imaging optical coherence tomography

    DEFF Research Database (Denmark)

    Lundberg, Lars Kristian; Vestergaard, Anders Højslet; Vergmann, Anna Stage

    for mean intergrader ICC were 0.97 ±0.027 and 0.95 ±0.03 (P=0.17). A shorter mean time was found for the Segmentation method (7.3 ±1.6 minutes vs. 9.0 ±1.8 minutes, Pmethods from the inbuilt Heidelberg Eye Explorer software were suitable for manual measurement of the CT and showed...... coherence tomography (EDI-SD OCT) has made it possible to visualize the choroid, and it is generally accepted that Heidelberg Spectralis OCT provides valid measurements of choroidal thickness (CT), although no fully automated software is commercially available. Two methods for CT-measurement are available...... in the Heidelberg software, but to our knowledge these have not been compared. Hence, the purpose of this study was to evaluate and validate the Segmentation method and the Ruler method for CT-measurement. Methods We used the Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany) to record EDI...

  13. Measuring Spatiotemporal Features of Land Subsidence, Groundwater Drawdown, and Compressible Layer Thickness in Beijing Plain, China

    Directory of Open Access Journals (Sweden)

    Yongyong Li

    2017-01-01

    Full Text Available Beijing is located on multiple alluvial-pluvial fans with thick Quaternary unconsolidated sediments. It has suffered serious groundwater drawdown and land subsidence due to groundwater exploitation. This study aimed to introduce geographical distribution measure methods into land subsidence research characterizing, geographically, land subsidence, groundwater drawdown, and compressible layer thickness. Therefore, we used gravity center analysis and standard deviational ellipse (SDE methods in GIS to statistically analyze their concentration tendency, principle orientation, dispersion trend, and distribution differences in 1995 (1999, 2007, 2009, 2011, and 2013. Results show that they were all concentrated in Chaoyang District of Urban Beijing. The concentration trend of land subsidence was consistent with that of groundwater drawdown. The principle orientation of land subsidence was SW–NE, which was more similar with that of the static spatial distribution of the compressible layer. The dispersion tendency of land subsidence got closer to that of the compressible layer with its increasing intensity. The spatial distribution difference between land subsidence and groundwater drawdown was about 0.2, and that between land subsidence and compressible layer thickness it decreased from 0.22 to 0.07, reflecting that the spatial distribution pattern of land subsidence was increasingly close to that of the compressible layer. Results of this study are useful for assessing the distribution of land subsidence development and managing groundwater resources.

  14. Dynamic measurement of liquid film thickness in stratified flow by using ultrasonic echo technique

    International Nuclear Information System (INIS)

    Serizawa, A.; Nagane, K.; Kamei, T.; Kawara, Z.; Ebisu, T.; Torikoshi, K.

    2004-01-01

    We developed a technique to measure time-dependent local film thickness in stratified air-water flow over a horizontal plate by using a time of flight of ultrasonic transmission. The ultrasonic echoes reflected at the liquid/air interfaces are detected by a conventional ultrasonic instrumentation, and the signals are analyzed by a personal computer after being digitalized by an A/D converter to give the time of flight for the ultrasonic waves to run over a distance of twice of the film thickness. A 3.8 mm diameter probe type ultrasonic transducer was used in the present work which transmits and receives 10 MHz frequency ultrasonic waves. The estimated spatial resolution with this arrangement is 0.075 mm in film thickness for water. The time resolution, which depends on both the A/D converter and the memory capacity was up to several tens Hz. We also discussed the sensitivity of the method to the inclination angle of the interfaces. (author)

  15. Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography

    International Nuclear Information System (INIS)

    Hirsch, J.E.

    2013-01-01

    We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. - Highlights: • A new property of superconducting particles is predicted. • Electron holography will show an apparent increase in thickness at low temperatures. • This will result from a predicted increase in the mean inner potential. • This will originate in expulsion of electrons from the interior to the surface. • This is not predicted by the conventional BCS theory of superconductivity

  16. The Use of an Intra-Articular Depth Guide in the Measurement of Partial Thickness Rotator Cuff Tears

    Directory of Open Access Journals (Sweden)

    Michael J. Carroll

    2013-01-01

    Full Text Available Purpose. The purpose of this study was to compare the accuracy of the conventional method for determining the percentage of partial thickness rotator cuff tears to a method using an intra-articular depth guide. The clinical utility of the intra-articular depth guide was also examined. Methods. Partial rotator cuff tears were created in cadaveric shoulders. Exposed footprint, total tendon thickness, and percentage of tendon thickness torn were determined using both techniques. The results from the conventional and intra-articular depth guide methods were correlated with the true anatomic measurements. Thirty-two patients were evaluated in the clinical study. Results. Estimates of total tendon thickness (r = 0.41, P = 0.31 or percentage of thickness tears (r = 0.67, P = 0.07 using the conventional method did not correlate well with true tendon thickness. Using the intra-articular depth guide, estimates of exposed footprint (r = 0.92, P = 0.001, total tendon thickness (r = 0.96, P = 0.0001, and percentage of tendon thickness torn (r = 0.88, P = 0.004 correlated with true anatomic measurements. Seven of 32 patients had their treatment plan altered based on the measurements made by the intra-articular depth guide. Conclusions. The intra-articular depth guide appeared to better correlate with true anatomic measurements. It may be useful during the evaluation and development of treatment plans for partial thickness articular surface rotator cuff tears.

  17. Study on the relationship between the thickness of the anterior cruciate ligament, anthropometric data and anatomical measurements on the knee

    Directory of Open Access Journals (Sweden)

    Victor Marques de Oliveira

    2016-04-01

    Full Text Available OBJECTIVES: To ascertain thickness measurements on the anterior cruciate ligament (ACL in its middle third on magnetic resonance imaging (MRI scans and to assess whether there is any association between variations in ligament thickness and patients' heights and ages, along with variations in the anatomical measurements on the knee. METHODS: MRI scans on 48 knees were evaluated. The anteroposterior size of the femoral condyles, interepicondylar distance, intercondylar distance and anteroposterior and mediolateral thicknesses of the ACL were measured. It was assessed whether there was any statistical relationship between ACL thickness and the patients' age, height or other measurements evaluated. RESULTS: The mean thickness of the middle third of the ACL was 4.5 mm in the sagittal plane and 4.3 mm in the frontal plane. The anteroposterior thickness of the ACL in its middle third had a positive relationship with the size of the lateral condyle. The mediolateral thickness of the ACL in its middle third had a positive relationship with the size of the lateral condyle and with the intercondylar distance in the axial plane. There was no relationship between the thickness of the ACL and the patients' age or height. CONCLUSION: The thickness of the ACL presented positive associations with the size of the lateral femoral condyle and the intercondylar distance.

  18. In vivo sweat film layer thickness measured with Fourier-domain optical coherence tomography

    CSIR Research Space (South Africa)

    Jonathan, E

    2008-01-01

    Full Text Available s Centre form the f th s pr t fi d id Keywords: Fourier-domain optical coherence tomography; Human sweat secretion; Sweat gland; Sweat duct; Hyperhidrosis growing list of triggers include cancer, glucose control disorder, mental stress, social..., that is, the gland, duct and pore(s). However, due to a slow imaging time, COCT is largely restricted to morphometry of human tissue and thickness measurement of biologic and biologic samples [12,13]. ARTICLE IN PRESS Fourier-domain optical coherence...

  19. Measurements of the thickness of model sea ice by UHF waves (abstract)

    OpenAIRE

    Takashima,Hayao; Yamakoshi,Hisao; Maeda,Toshio; Sakurai,Akio

    1993-01-01

    It is indispensable to know the dielectric constant of model sea ice in order to detect the ice thickness by radar. The authors measured the dielectric constsnt of model sea ice by the space reflection method using UHF waves. A UHF signal is swept from 200MHz to 1000MHz and is transmitted from an antenna toward the model sea ice set on a metal sheet. The transmitting antenna is a conical log spiral antenna for a right circular polarized wave. The receiving antenna is an inverse type antenna s...

  20. Measurement of through-thickness thermal diffusivity of thermoplastics using thermal wave method

    Science.gov (United States)

    Singh, R.; Mellinger, A.

    2015-04-01

    Thermo-physical properties, such as thermal conductivity, thermal diffusivity and specific heat are important quantities that are needed to interpret and characterize thermoplastic materials. Such characterization is necessary for many applications, ranging from aerospace engineering to food packaging, electrical and electronic industry and medical science. In this work, the thermal diffusivity of commercially available polymeric films is measured in the thickness direction at room temperature using thermal wave method. The results obtained with this method are in good agreement with theoretical and experimental values.

  1. Experimental approach to measure thick target neutron yields induced by heavy ions for shielding

    Directory of Open Access Journals (Sweden)

    Trinh N.D.

    2017-01-01

    Full Text Available Double differential (angular and energy neutron distributions were measured using an activation foil technique. Reactions were induced by impinging two low-energy heavy-ion beams accelerated with the GANIL CSS1 cyclotron: (36S (12 MeV/u and 208Pb (6.25 MeV/u onto thick natCu targets. Results have been compared to Monte-Carlo calculations from two codes (PHITS and FLUKA for the purpose of benchmarking radiation protection and shielding requirements. This comparison suggests a disagreement between calculations and experiment, particularly for high-energy neutrons.

  2. A Microwave Free-Space Method Using Artificial Lens with Anti-reflection Layer

    Science.gov (United States)

    Zhang, Yangjun; Aratani, Yuki; Nakazima, Hironari

    2017-12-01

    This paper describes a microwave free-space method using flat artificial lens antennas with anti-reflection layer. The lens antenna is made of an artificial material of metal particle. Comparing with our previous study, Anti-reflection (AR) layers are supplemented to the lens in this study to obtain a wave matching on the air-lens interface. The improved lens is in a disk shape of 50 mm diameter and 5.9 mm thickness. The lens is applied in a free-space setup, in which it is set in front of a patch antenna resonating at 15 GHz to get a high gain. The free-space setup is used to measure microwave attenuation and phase shift through a sawdust sample. The experimental results show that the multiple-reflection in the free-space method becomes small, because the reflection on air-lens interface has been reduced. The proposed AR lens antenna is flat and very small in the size. It is possible to construct a very compact and low cost free-space setup using the improved lens.

  3. Developing the new method measuring thickness and quality of bottom sediments in using ultrasonic wave

    Science.gov (United States)

    Ishikawa, Tomonari; Matsumoto, Yoshitaka; Hozumi, Naohiro

    2017-07-01

    Measuring the quality and thickness of bottom sediment that it causes some environmental problem, the shortage of water storage volume and anaerobic zone in the bottom of reservoirs, takes huge costs and long time. The purpose of our research is to develop a new method to measure the thickness and size characteristics of bottom sediment using ultrasonic waves that allow obtaining the quality of it indirectly. This new method applies the echo characteristic of bottom sediment in each particle size using the higher frequency than another method, which uses for measuring geological layer at seabed survey. In this research, we attempted to estimate the particle size of bottom sediment by ultrasonic waves irradiating from two different directions such as horizontal and vertical direction, and compare these experiments. We use sediment that we sampled from the lake bottom classified by particle size. At first, we acquired the results that show a relation between particle size and intensity; the obtained echo intensities, which were observed with oscilloscope, were changed depending on the particle sizes. In addition, peaks, which were obtained by power spectrum analysis, appeared on the same frequency band even though the different particle size. However the relation between the experiments of horizontal and vertical direction is not clear. This research indicated the possibility of estimating the characteristics of each particle size in bottom sediment by ultrasonic waves.

  4. Remote measurement of oxide thickness at Oldbury-on-Severn power station using ultrasonic spectroscopy

    International Nuclear Information System (INIS)

    Peck, J.; Thompson, V.

    For some years ultrasonic spectroscopy has been used in the boilers at Oldbury-on-Severn to measure the thickness of oxide on inaccessible steel surfaces. Because of concern about the integrity of roof thermal shield plates, it was decided to attempt measurements of the oxide thickness in the interface between the shield plates and the fishplates holding them. A tool for use on the Oldbury Mk III manipulator was designed by Station staff with assistance from SSD and BNL and this was first used in the reactor during the 1979 annual overhaul. Measurements were successfully made on the fish plates and on some other components. The design features of the tool and the basic operating sequence will be outlined. Special care was required when testing components for which the tool was not originally designed. A particular problem was caused by the nature of the component surface and this was overcome by modifying the operating sequence. Minor shortcomings of the equipment were noted and the steps taken to effect improvements will be described. Experience and results of the second programme of inspection using the tool during the 1980 overhaul will be reported. (author)

  5. Sea ice thickness measurements collected during the LOMROG 2007 and 2009 expeditions

    DEFF Research Database (Denmark)

    Skourup, Henriette; Forsberg, René; Hanson, Susanne

    According to scientific measurements, the Arctic sea ice extent has declined dramatically over the past thirty years, with the most extreme decline seen in the summer melt season. Other observations indicate that the sea ice has become thinner and perennial ice less widely distributed. The proces......According to scientific measurements, the Arctic sea ice extent has declined dramatically over the past thirty years, with the most extreme decline seen in the summer melt season. Other observations indicate that the sea ice has become thinner and perennial ice less widely distributed....... The processes involved in the declining sea ice are not fully understood. This is primarily due to a lack of knowledge of the variety and high spatial resolution of, e.g. snow depth, ice thickness and morphology, which are difficult or impossible to obtain remotely. During the LOMROG expeditions in 2007...... and 2009 we have collected a unique data set of late summer sea ice thickness, freeboard height and snow depth from the high Arctic Ocean during the time of the annual minimum sea ice extent. The data were collected by on-the-ground drilling and EM measurements. Here we give a brief overview of the data...

  6. Effects of X-ray tube parameters on thickness measure precision in X-ray profile gauge

    International Nuclear Information System (INIS)

    Miao Jichen; Wu Zhifang; Xing Guilai

    2011-01-01

    Instantaneous profile gauge technology has been widely used in metallurgy industry because it can on-line get the profile of steel strip. It has characters of high measure precision and wide measure range, but the X-ray tube parameters only can be set few different values during measurement. The relations of thickness measure precision and X-ray tube current, X-ray tube voltage were analyzed. The results show that the X-ray tube current affects the thickness measure precision and the X-ray tube voltage determines the thickness measure range. The method of estimating the X-ray current by thickness measure precision was provided in the end. This method is the base of X-ray source selection and X-ray source parameter's setting in the instantaneous profile gauge. (authors)

  7. Signal processing and analysis for copper layer thickness measurement within a large variation range in the CMP process

    Science.gov (United States)

    Li, Hongkai; Zhao, Qian; Lu, Xinchun; Luo, Jianbin

    2017-11-01

    In the copper (Cu) chemical mechanical planarization (CMP) process, accurate determination of a process reaching the end point is of great importance. Based on the eddy current technology, the in situ thickness measurement of the Cu layer is feasible. Previous research studies focus on the application of the eddy current method to the metal layer thickness measurement or endpoint detection. In this paper, an in situ measurement system, which is independently developed by using the eddy current method, is applied to the actual Cu CMP process. A series of experiments are done for further analyzing the dynamic response characteristic of the output signal within different thickness variation ranges. In this study, the voltage difference of the output signal is used to represent the thickness of the Cu layer, and we can extract the voltage difference variations from the output signal fast by using the proposed data processing algorithm. The results show that the voltage difference decreases as thickness decreases in the conventional measurement range and the sensitivity increases at the same time. However, it is also found that there exists a thickness threshold, and the correlation is negative, when the thickness is more than the threshold. Furthermore, it is possible that the in situ measurement system can be used within a larger Cu layer thickness variation range by creating two calibration tables.

  8. Intima-Media Thickness Measurements in the Fetus and Mother During Pregnancy

    DEFF Research Database (Denmark)

    Galjaard, Sander; Pasman, Suzanne A; Ameye, Lieveke

    2014-01-01

    Fetal intima-media thickness (IMT) has been suggested as a marker of pre-clinical atherosclerosis, and maternal IMT could be altered through dynamic circumstances related to pregnancy. We investigated the feasibility of measurement of IMT at four pre-defined fetal and four pre-defined maternal...... arterial locations to determine vascular changes that could be associated with impaired vascular function. IMT was measured from the first to third trimester (12-34 wk), in 38 low-risk pregnancies. We imaged a 10-mm region of interest using a Mindray (Shenzhen, China) high-resolution ultrasound machine...... pregnancy. There was a significant relation between gestational age and IMT in the umbilical artery (p = 0.03) and a significant relation between body mass index and IMT in the maternal common carotid artery (p = 0.01). IMT measurements are feasible in some maternal and fetal vessels of interest. Further...

  9. Beveled fiber-optic probe couples a ball lens for improving depth-resolved fluorescence measurements of layered tissue: Monte Carlo simulations

    International Nuclear Information System (INIS)

    Jaillon, Franck; Zheng Wei; Huang Zhiwei

    2008-01-01

    In this study, we evaluate the feasibility of designing a beveled fiber-optic probe coupled with a ball lens for improving depth-resolved fluorescence measurements of epithelial tissue using Monte Carlo (MC) simulations. The results show that by using the probe configuration with a beveled tip collection fiber and a flat tip excitation fiber associated with a ball lens, discrimination of fluorescence signals generated in different tissue depths is achievable. In comparison with a flat-tip collection fiber, the use of a large bevel angled collection fiber enables a better differentiation between the shallow and deep tissue layers by changing the excitation-collection fiber separations. This work suggests that the beveled fiber-optic probe coupled with a ball lens has the potential to facilitate depth-resolved fluorescence measurements of epithelial tissues

  10. Beveled fiber-optic probe couples a ball lens for improving depth-resolved fluorescence measurements of layered tissue: Monte Carlo simulations.

    Science.gov (United States)

    Jaillon, Franck; Zheng, Wei; Huang, Zhiwei

    2008-02-21

    In this study, we evaluate the feasibility of designing a beveled fiber-optic probe coupled with a ball lens for improving depth-resolved fluorescence measurements of epithelial tissue using Monte Carlo (MC) simulations. The results show that by using the probe configuration with a beveled tip collection fiber and a flat tip excitation fiber associated with a ball lens, discrimination of fluorescence signals generated in different tissue depths is achievable. In comparison with a flat-tip collection fiber, the use of a large bevel angled collection fiber enables a better differentiation between the shallow and deep tissue layers by changing the excitation-collection fiber separations. This work suggests that the beveled fiber-optic probe coupled with a ball lens has the potential to facilitate depth-resolved fluorescence measurements of epithelial tissues.

  11. Optical Coherence Tomography–Based Corneal Power Measurement and Intraocular Lens Power Calculation Following Laser Vision Correction (An American Ophthalmological Society Thesis)

    Science.gov (United States)

    Huang, David; Tang, Maolong; Wang, Li; Zhang, Xinbo; Armour, Rebecca L.; Gattey, Devin M.; Lombardi, Lorinna H.; Koch, Douglas D.

    2013-01-01

    Purpose: To use optical coherence tomography (OCT) to measure corneal power and improve the selection of intraocular lens (IOL) power in cataract surgeries after laser vision correction. Methods: Patients with previous myopic laser vision corrections were enrolled in this prospective study from two eye centers. Corneal thickness and power were measured by Fourier-domain OCT. Axial length, anterior chamber depth, and automated keratometry were measured by a partial coherence interferometer. An OCT-based IOL formula was developed. The mean absolute error of the OCT-based formula in predicting postoperative refraction was compared to two regression-based IOL formulae for eyes with previous laser vision correction. Results: Forty-six eyes of 46 patients all had uncomplicated cataract surgery with monofocal IOL implantation. The mean arithmetic prediction error of postoperative refraction was 0.05 ± 0.65 diopter (D) for the OCT formula, 0.14 ± 0.83 D for the Haigis-L formula, and 0.24 ± 0.82 D for the no-history Shammas-PL formula. The mean absolute error was 0.50 D for OCT compared to a mean absolute error of 0.67 D for Haigis-L and 0.67 D for Shammas-PL. The adjusted mean absolute error (average prediction error removed) was 0.49 D for OCT, 0.65 D for Haigis-L (P=.031), and 0.62 D for Shammas-PL (P=.044). For OCT, 61% of the eyes were within 0.5 D of prediction error, whereas 46% were within 0.5 D for both Haigis-L and Shammas-PL (P=.034). Conclusions: The predictive accuracy of OCT-based IOL power calculation was better than Haigis-L and Shammas-PL formulas in eyes after laser vision correction. PMID:24167323

  12. Air-coupled ultrasonic through-transmission thickness measurements of steel plates.

    Science.gov (United States)

    Waag, Grunde; Hoff, Lars; Norli, Petter

    2015-02-01

    Non-destructive ultrasonic testing of steel structures provide valuable information in e.g. inspection of pipes, ships and offshore structures. In many practical applications, contact measurements are cumbersome or not possible, and air-coupled ultrasound can provide a solution. This paper presents air-coupled ultrasonic through-transmission measurements on a steel plate with thicknesses 10.15 mm; 10.0 mm; 9.8 mm. Ultrasound pulses were transmitted from a piezoelectric transducer at normal incidence, through the steel plate, and were received at the opposite side. The S1, A2 and A3 modes of the plate are excited, with resonance frequencies that depend on the material properties and the thickness of the plate. The results show that the resonances could be clearly identified after transmission through the steel plate, and that the frequencies of the resonances could be used to distinguish between the three plate thicknesses. The S1-mode resonance was observed to be shifted 10% down compared to a simple plane wave half-wave resonance model, while the A2 and S2 modes were found approximately at the corresponding plane-wave resonance frequencies. A model based on the angular spectrum method was used to predict the response of the through-transmission setup. This model included the finite aperture of the transmitter and receiver, and compressional and shear waves in the solid. The model predicts the frequencies of the observed modes of the plate to within 1%, including the down-shift of the S1-mode. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Measurements of diffusive sublayer thicknesses in the ocean by alabaster dissolution, and their implications for the measurements of benthic fluxes

    Science.gov (United States)

    Santschi, Peter H.; Anderson, Robert F.; Fleisher, Martin Q.; Bowles, Walter

    1991-06-01

    Fluxes of reactive chemical species across the sediment-water interface can profoundly influence the dominant biogeochemical cycles in the worlds ocean. However, reliable in-situ measurements of benthic fluxes of many reactive species cannot be carried out without adjustment of stirring rates inside benthic flux chambers to match boundary layer conditions prevailing outside. A simple method to compare flow levels consists of measurements of gypsum dissolution rates inside benthic chambers and on the seafloor. The measurement of the diffusion-controlled dissolution rate of gypsum allows the estimation of the diffusive sublayer thickness and the time-averaged bottom stress on the seafloor. This method had previously been intercalibrated with the stress sensor method in flumes and inside benthic chambers. We describe here free-vehicle deployments of alabaster plates on the bottom of the ocean which gave results consistent with hydrodynamic theory. Errors in the calculated diffusive sublayer thicknesses were estimated to be about 10-15% for typical deployment conditions in the ocean. Current velocities 5 m off the bottom, which were measured concurrently during two deployments, allowed for comparisons with hydrodynamic predictions of diffusive sublayer thicknesses. The values obtained this way agreed within 15%. The measured mass transfer velocity was found to correlate with the plate dimension L, to the power of ⅓. This confirms the theoretical procedure for extrapolating to infinite plate size when calculating the sublayer impedance of solute fluxes from sediments (where L is large). Typical values of diffusive sublayer thicknesses, corrected to infinite plate size, were 1200 μm for current velocities, U100, of 2 cm s-1, and 500 μm at 8 cm s-1. Furthermore, values of friction velocities calculated from alabaster dissolution were compared with those using stress sensors. Gypsum plate values of u* were 0 and 30% lower than skin friction values of u*, at u* values

  14. Prototype gauge for measuring contour and wall thicknesses of hemispherical parts

    International Nuclear Information System (INIS)

    Aarts, H.J.; Robertson, J.H.

    1976-01-01

    A prototype gauge (gage) was designed and fabricated using air bearings in a new configuration to provide less error and distortion during inspection of hemispherical parts. No wear occurs on the moving parts during operations and accuracy of alignment is maintained. The gauge will check outside radial distance, inside radial, and outside radial and wall, and inner radial and wall thicknesses of parts. The gauge contains only four moving parts, which increases the measuring accuracy. A horizontal table rotates. A table mounted on the horizontal table at 45 0 rotates through two transducers. All moving parts are mounted on hydrostatic gas bearings. Laser interferometric, air-bearing gauge heads are used to obtain the required data. Investigation of a hemispherical part is in any desired spiral path from equator to pole. Measurement information is obtained from two laser interferometric transducers using linear air bearings. The transducers use a Spectra Physics Model-120 helium and neon laser. Working range of each transducer is 1.5 inches. The fringe voltage signals are amplified and converted to inches to be displayed on a digital readout. A punched paper tape contains the nominal inside diameter (ID) and outside diameter (OD) information in Binary Coded Decimal form. The tape is fed into a digital computer which calculates error information on ID, OD, and wall thickness. This information is converted to analog form and displayed simultaneously on a strip-chart recorder

  15. Reliability of ultrasound imaging for the measurement of abdominal muscle thickness in typically developing children

    Directory of Open Access Journals (Sweden)

    M. Unger

    2010-01-01

    Full Text Available Introduction: A bdominal muscles are key to both posture andgait in both children with typical development (TD and with disabilities.Ultrasound (US imaging is a potential non-invasive method for investigatingactivity in these muscles. This study therefore aimed to determine the inter-tester and intra-tester reliability of B-mode US for investigating transverseabdominus (TrA , rectus abdominus (RA and external- (EO and internaloblique (IO muscle activity in children with TD. Design: A  prospective cor-relational descriptive study.  Participants:  Eighty six, 6-13year old children from one private and one public mainstream school. Outcome measures: Two sets of B-mode US images where captured per subject during rest and during head-up, resisted head-up and resisted sling activities. Intra-class Correlation Coefficients (ICC and standard error of measurement (SEM were used to analyse the data. Results: Good correlation was found for both test - retest condi-tions for all four muscles tested during rest: 0.91(TrA ; 0.90(IO; 0.91(EO; 0.94(RA for intra-tester reliability and0.74(TrA ; 0.88(IO; 0.74(EO; 0.83(RA for inter-tester reliability. Repeatability of thickness measures during activity however showed variation in recruitment patterns. A  significant correlation was found between age and BMI andresting abdominal muscle thickness (p<0.001. Conclusion: The study supports the reliability of US measurement of resting abdominal muscles and of the RA  under active conditions in children aged six to 13. However the stability o measurement of the other muscles under active conditions still needs to be established.

  16. Comparison of Central Corneal Thickness Measurements Using Ultrasonic Pachymetry, Anterior Segment OCT and Noncontact Specular Microscopy.

    Science.gov (United States)

    Scotto, Riccardo; Bagnis, Alessandro; Papadia, Marina; Cutolo, Carlo Alberto; Risso, Domenico; Traverso, Carlo Enrico

    2017-10-01

    To evaluate and compare central corneal thickness (CCT) values measured with anterior segment optical coherence tomography (AS-OCT), noncontact specular microscopy (NCSM), and ultrasound pachymetry (USP). CCT was measured in 182 healthy eyes without ocular abnormalities other than refractive errors. Three consecutive measurements of CCT by the same examiner were obtained during the same session. The testing sequence of AS-OCT and NCSM was randomly selected. The USP always was performed after the noncontact examinations. The average CCT measured by AS-OCT, NCSM, and USP were 535.8±35.5, 547.7±38.2, and 537.4±37.5 μm, respectively. The mean differences between modalities were 11.8±14.7 μm (POCT, 10.3±17.7 μm (POCT. AS-OCT, NCSM, and USP showed an overall strong agreement in measuring CCT. However, CCT measurements with AS-OCT showed a good correlation to those obtained by USP, NCSM tended to give statistically significant higher CCT readings than either alternative and showed the worse repeatability indices. On the basis of our results, CCT measurement obtained with different instruments cannot be considered directly interchangeable.

  17. Measurements of heel pad thickness in normal Koreans by ultrasound and conventional X-ray

    International Nuclear Information System (INIS)

    Chung, Bong Lin; Kim, Yang Su; Kim, Kun Sang

    1987-01-01

    The measurement of heel pad thickness (HPT) has never been done by ultrasound in healthy Korean. To establish normal standard value of HPT in Koreans, 87 healthy volunteers were examined using 10MHZ high resolution ultrasound. As a control, measurement of HPT were done in 46 healthy volunteers on conventional X-ray. The results are as follows; 1. In ultrasonic measurement cases, the mean value of right HPT is 15.8 ± 1.9 mm and the mean value of left HPT is 15.4 ± 2.0mm. In X-ray measurement cases, the mean value of right HPT is 19.9 ± 2.17mm and the mean value of left HPT is 19.8 ± 2.28mm. 2. Maximum value of HPT is 20.8mm in ultrasonic measurement cases, 23mm in X-ray measurement cases. 3. The value of HPT is well correlated with weight, height both in ultrasound and in X-ray measurement (ρ < 0.05). Correlation between the value of HPT and age is not evident (correlation coefficients = -0.18, -0.15). There is no significant difference between left and right foot (ρ < 0.05), and male and female (ρ < 0.05). 4. The results can be considered that there is no significant difference in normal standard value of HPT between Koreans and white, and that upper limit of normal in Koreans is 23mm by conventional X-ray

  18. Understanding first-year ice thickness variability using IceBridge measurements and drift track analysis

    Science.gov (United States)

    Bradley, A. C.; Palo, S. E.

    2016-12-01

    In a first-year ice dominated environment, positive climate feedbacks in the Arctic persist from year to year when increased summertime melt results in decreased ice growth the following winter. In this presentation, we describe a novel approach to evaluating the impacts of delayed freeze-up, oceanic heat flux, and variable atmospheric forcing on end-of-season first year ice thickness. Parcels of first-year sea ice selected from IceBridge sea ice thickness retrievals are tracked backwards through their winter drift paths using the Pathfinder Ice Motion product. The freeze-up date for each parcel is determined by tracing the drift path through the SSMI Ice Concentration product, and summertime mixed layer heat is estimated from the NOAA Optimal Interpolation SST product at the locations of freeze-up and the end-of-season measurement. Over-winter atmospheric forcing is estimated from integrating the drift path through the MERRA2 reanalysis product using a simple 1-D ice growth model. The end of season ice thickness distributions can then be analyzed in the context of the processes that drive ice growth. The summer mixed layer temperature at the end-of-season measurement location, the integrated atmospheric forcing, and the length of the growth season are the three parameters, after end-of-season snow depth, most correlated with the ice thickness. Controlling for these other factors, delaying freeze-up by one week leads to 5.3 cm thinner ice cover at the end of the season. Warming summer ocean temperatures contribute to delayed freeze-up, but even after controlling for changing freeze-up dates and atmospheric forcing, each degree (C) of warmer summertime temperatures results in 1.9 centimeters of thinner ice cover at the end of the winter season. This indicates that oceanic heat flux due to trapped seasonal heat compounds the loss of ice growth due to delayed freeze-up resulting in thinner first-year ice cover in the Arctic seasonal ice zones.

  19. Measurement precision and normal range of endometrial thickness in a postmenopausal population by transvaginal ultrasound

    DEFF Research Database (Denmark)

    Warming, L; Ravn, Pernille; Skouby, Sven O.

    2002-01-01

    of the ET. Measurements were performed by transvaginal ultrasound. A subset of the women (n = 178) was examined twice 3 months to 2 years apart to assess the long-term variability. RESULTS: Cross-sectionally, ET varied with length of menopause. During the first 5 years after menopause (YSM) the mean ET...... was 2.3 mm but it decreased by 0.03 mm/year (P changes (P = 0.13). Thereafter there was a minimal increase of 0.01 mm/year (P changes on ET, only women who had...... reached the menopause more than 5 years earlier were entered into the subsequent long-term study. The mean ET was 2.0 mm +/- 1.0 mm with no significant differences within or between the observers' measurements. The precision errors were less than 1 mm. CONCLUSIONS: The normal range of the thickness...

  20. Confiabilidade da medida de espessuras musculares pela ultrassonografia Reliability of muscle thickness measurements using ultrasound

    Directory of Open Access Journals (Sweden)

    Paulo Sergio Chagas Gomes

    2010-02-01

    Full Text Available OBJETIVO: Determinar a confiabilidade das medidas de espessuras dos músculos flexores e extensores do cotovelo e joelho pela ultrassonografia (US, quantificando o erro típico associado a essas medidas (ETM. MÉTODOS: A confiabilidade (duas medidas interdias foi determinada em 15 voluntários aparentemente saudáveis (oito mulheres, 33,9 ± 11,4 anos, 76 ± 21kg, 170 ± 10cm. As imagens da musculatura flexora (FC e extensora do cotovelo (EC e flexora (FJ e extensora do joelho (EJ foram obtidas pela US bidimensional no modo B, utilizando transdutor de 7,5MHz. As espessuras do tecido muscular compreendidas entre as interfaces com o osso e com o tecido adiposo foram medidas em sítios anatômicos identificados e registrados para ser repetidos na segunda medida. RESULTADOS: A ANOVA não identificou diferenças significativas entre as medidas repetidas. Os coeficientes de correlação intraclasse foram FC = 0,970, EC = 0,971, FJ = 0,555 e EJ = 0,929 (P PURPOSE: To determine the reliability of muscle thickness measurements of elbow and knee flexors and extensors using ultrasound, and to quantify the typical error associated to the measurements (TEM. METHODS: The test-retest reliability was determined in 15 apparently healthy volunteers (8 women, 34 ± 11 years, 76 ± 21 kg, 170 ± 10 cm. The images of elbow flexors (EF and extensors (EE and knee flexors (KF and extensors (KE were obtained using a two dimensional mode B ultrasound instrument with a 7.5 MHz transducer. Muscle thickness between the adipose tissue and bone interfaces were measured at anatomical landmarks previously identified and recorded to assure the exact site for the retest. RESULTS: ANOVA did not identify any significant differences between the repeated measurements. Intraclass correlation coefficients (ICC of each pair of measure were EF = 0.970, EE = 0.971, KF = 0.555 e KE = 0.929 (P < 0.05 for all. The coefficients of variation were 3.9 %, 6.1 %, 6.6 % e 4.6 %, and TEM 1.3 mm, 1

  1. An enhanced HPIV configuration for flow measurement through thick distorting windows

    Science.gov (United States)

    Alcock, R. D.; Garner, C. P.; Halliwell, N. A.; Coupland, J. M.

    2004-04-01

    This paper reports on a new holographic particle image velocimetry configuration and analysis procedure that can be used to measure particle displacement through thick distorting windows. The technique builds upon the scanning fibre probe based object conjugate reconstruction geometry; however it avoids the requirement of using a holographic optical element to correct for window distortion of the beams. Removal of the distortion is instead accomplished by using a ray trace mapping between the wave vectors scattered by the particles at the time of each exposure and those measured by the interrogation system. The technique is ideally suited to the study of flow structure within the combustion chamber of a diesel engine, and preliminary experimental results that attempt to assess the accuracy of the technique in this situation are presented.

  2. Comparison of methods used to measure the thickness of soft tissues and their influence on the evaluation of tensile stress.

    Science.gov (United States)

    O'Leary, Siobhan A; Doyle, Barry J; McGloughlin, Tim M

    2013-07-26

    Measuring the physical dimensions of soft tissue is difficult due to its deformable nature. Such measurements are used to evaluate the tissue's mechanical properties. Imprecise measurements of the tissue's thickness can alter the assessment of tensile stress which may have significant clinical relevance when used as a diagnostic tool. The performance of routinely used measurement methods including a (i) vernier calipers, (ii) micrometer, (iii) thickness gauge, (iv) glass slide technique coupled with (i) and (ii) and a (v) laser displacement sensor were assessed by comparing them to a photogrammetric technique which was considered to be the measurement standard. All measurements were performed on two tissue types: porcine aorta and human intraluminal thrombus from an abdominal aortic aneurysm (AAA) and results were compared against predetermined criteria whose limits represented a 10% change in experimentally derived tensile stress. The inter-rater and retest reliability of the vernier calipers, micrometer and thickness gauge were also investigated. The thickness gauge was shown to be the most reliable and could accurately measure the thickness of aortic tissue. The conditions of the criteria were not met by any instrument used to measure the thickness of the AAA intraluminal thrombus, however, the micrometer, which proved highly reliable, was considered the most suitable (effects on tensile stress: +14.7%). For both tissues the glass slide and laser techniques significantly over estimated the thickness measurement altering the tensile stress by up to -29.6%. This study highlights the effects of inaccurate measurements on the assessment of tensile stress and recommends a thickness gauge be used to measure structured tissue (aorta) and a micrometer for unstructured tissue (AAA intraluminal thrombus). Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Morphological changes in the conjunctiva, episclera and sclera following short-term miniscleral contact lens wear in rigid lens neophytes.

    Science.gov (United States)

    Alonso-Caneiro, David; Vincent, Stephen J; Collins, Michael J

    2016-02-01

    To quantify the influence of short-term wear of miniscleral contact lenses on the morphology of the corneo-scleral limbus, the conjunctiva, episclera and sclera. OCT images of the anterior eye were captured before, immediately following 3h of wear and then 3h after removal of a miniscleral contact lens for 10 young (27 ± 5 years) healthy participants (neophyte rigid lens wearers). The region of analysis encompassed 1mm anterior, to 3.5mm posterior to the scleral spur. Natural diurnal variations in thickness were measured on a separate day and compensated for in subsequent analyses. Following 3h of lens wear, statistically significant tissue thinning was observed across all quadrants, with a mean decrease in thickness of -24.1 ± 3.6 μm (pscleral spur (-48.2 ± 5.7 μm), corresponding to the approximate edge of the lens landing zone. Compression of the conjunctiva/episclera accounted for about 70% of the changes. Optimal fitting miniscleral contact lenses worn for three hours resulted in significant tissue compression in young healthy eyes, with the greatest thinning observed superiorly, potentially due to the additional force of the eyelid, with a partial recovery of compression 3h after lens removal. Most of the morphological changes occur in the conjunctiva/episclera layers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Geophysical surveying in the Sacramento Delta for earthquake hazard assessment and measurement of peat thickness

    Science.gov (United States)

    Craig, M. S.; Kundariya, N.; Hayashi, K.; Srinivas, A.; Burnham, M.; Oikawa, P.

    2017-12-01

    Near surface geophysical surveys were conducted in the Sacramento-San Joaquin Delta for earthquake hazard assessment and to provide estimates of peat thickness for use in carbon models. Delta islands have experienced 3-8 meters of subsidence during the past century due to oxidation and compaction of peat. Projected sea level rise over the next century will contribute to an ongoing landward shift of the freshwater-saltwater interface, and increase the risk of flooding due to levee failure or overtopping. Seismic shear wave velocity (VS) was measured in the upper 30 meters to determine Uniform Building Code (UBC)/ National Earthquake Hazard Reduction Program (NEHRP) site class. Both seismic and ground penetrating radar (GPR) methods were employed to estimate peat thickness. Seismic surface wave surveys were conducted at eight sites on three islands and GPR surveys were conducted at two of the sites. Combined with sites surveyed in 2015, the new work brings the total number of sites surveyed in the Delta to twenty.Soil boreholes were made at several locations using a hand auger, and peat thickness ranged from 2.1 to 5.5 meters. Seismic surveys were conducted using the multichannel analysis of surface wave (MASW) method and the microtremor array method (MAM). On Bouldin Island, VS of the surficial peat layer was 32 m/s at a site with pure peat and 63 m/s at a site peat with higher clay and silt content. Velocities at these sites reached a similar value, about 125 m/s, at a depth of 10 m. GPR surveys were performed at two sites on Sherman Island using 100 MHz antennas, and indicated the base of the peat layer at a depth of about 4 meters, consistent with nearby auger holes.The results of this work include VS depth profiles and UBC/NEHRP site classifications. Seismic and GPR methods may be used in a complementary fashion to estimate peat thickness. The seismic surface wave method is a relatively robust method and more effective than GPR in many areas with high clay

  5. Low-temperature measurements of 32nm-thick N-type piezoresistive cantilevers

    Science.gov (United States)

    Tewary, Anuranjita; Bartsch, M. S.; Kenny, T. W.

    2002-03-01

    Advances in the field of Magnetic Resonance Force Microscopy (MRFM) are demanding the development of increasingly sensitive cantilevers. Recently, piezoresistive sensing has become an progressively viable alternative to optical detection methods as the sensitivity and resolution of piezoresistive cantilevers has dramatically improved. Harley demonstrated single crystal cantilevers 900A in thickness capable of resolving 8.6fN on a 1kHz bandwidth[1]. More recently, Liang reported 700A piezoresistive cantilevers with resolution of 1.6fN on the same bandwidth[2]. This work presents the latest developments in the fabrication of ultrathin single-crystal silicon piezoresistive cantilvers. Levers 320A thick have been successfully fabricated and released, and we believe that with further process refinement, they will continue the performance trends established by Harley and Liang. We will present our measurements of the temperature dependence on the gage factor and focus on the feasibility of using piezoresistive cantilevers for MRFM. [1]Harley JA, Kenny TW, APPLIED PHYSICS LETTERS v. 75(#2) pp. 289-291 JUL 12, 1999. [2]Liang, Y. PhD Thesis, Stanford University, 2001. We would like to thank NSF Goali Program, Grant No. CMS-997-1414-001 for their support.

  6. The Effects of Smoking on Ultrasonographic Thickness and Elastosonographic Strain Ratio Measurements of Distal Femoral Cartilage

    Directory of Open Access Journals (Sweden)

    Harun R. Gungor

    2016-04-01

    Full Text Available Although adverse effects of smoking on bone health are all well known, data on how smoking interacts with cartilage structure in otherwise healthy individuals remains conflicting. Here, we ascertain the effects of cigarette smoking on sonoelastographic properties of distal femoral cartilage in asymptomatic adults. Demographic characteristics and smoking habits (packets/year of healthy volunteers were recorded. Medial, intercondylar, and lateral distal femoral cartilage thicknesses and strain ratios on the dominant extremity were measured with ultrasonography (US and real time US elastography. A total of 88 subjects (71 M, 17 F; aged 18–56 years, N = 43 smokers and N = 45 nonsmokers were evaluated. Mean amount of cigarette smoking was 10.3 ± 8.9 (1–45 packets/year. Medial, intercondylar and lateral cartilage were thicker in smokers than nonsmokers (p = 0.002, p = 0.017, and p = 0.004, respectively. Medial distal femoral cartilage strain ratio was lower in smokers (p = 0.003. The amount of smoking was positively correlated with cartilage thicknesses and negatively correlated with medial cartilage strain ratios (p < 0.05. Femoral cartilage is thicker in smokers but has less strain ratio representing harder cartilage on the medial side. Future studies are needed to understand how these structural changes in the knee cartilage should be interpreted with regard to the development of knee osteoarthritis in smokers.

  7. Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

    Energy Technology Data Exchange (ETDEWEB)

    Osipenko, M., E-mail: osipenko@ge.infn.it [INFN, sezione di Genova, 16146 Genova (Italy); Ripani, M. [INFN, sezione di Genova, 16146 Genova (Italy); Alba, R. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Ricco, G. [INFN, sezione di Genova, 16146 Genova (Italy); Schillaci, M. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Barbagallo, M. [INFN, sezione di Bari, 70126 Bari (Italy); Boccaccio, P. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Celentano, A. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy); Colonna, N. [INFN, sezione di Bari, 70126 Bari (Italy); Cosentino, L.; Del Zoppo, A.; Di Pietro, A. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Esposito, J. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Figuera, P.; Finocchiaro, P. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Kostyukov, A. [Moscow State University, Moscow 119992 (Russian Federation); Maiolino, C.; Santonocito, D.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Viberti, C.M. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy)

    2013-09-21

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a {sup 3}He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60–70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

  8. Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

    Science.gov (United States)

    Osipenko, M.; Ripani, M.; Alba, R.; Ricco, G.; Schillaci, M.; Barbagallo, M.; Boccaccio, P.; Celentano, A.; Colonna, N.; Cosentino, L.; Del Zoppo, A.; Di Pietro, A.; Esposito, J.; Figuera, P.; Finocchiaro, P.; Kostyukov, A.; Maiolino, C.; Santonocito, D.; Scuderi, V.; Viberti, C. M.

    2013-09-01

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a 3He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10 MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60-70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

  9. Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

    International Nuclear Information System (INIS)

    Osipenko, M.; Ripani, M.; Alba, R.; Ricco, G.; Schillaci, M.; Barbagallo, M.; Boccaccio, P.; Celentano, A.; Colonna, N.; Cosentino, L.; Del Zoppo, A.; Di Pietro, A.; Esposito, J.; Figuera, P.; Finocchiaro, P.; Kostyukov, A.; Maiolino, C.; Santonocito, D.; Scuderi, V.; Viberti, C.M.

    2013-01-01

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a 3 He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60–70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed

  10. Effect of pupillary dilation on Haigis formula-calculated intraocular lens power measurement by using optical biometry

    Directory of Open Access Journals (Sweden)

    Khambhiphant B

    2016-07-01

    Full Text Available Bharkbhum Khambhiphant,1 Suganlaya Sasiwilasagorn,2 Nattida Chatbunchachai,3 Krit Pongpirul2,4 1Department of Ophthalmology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, 2Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University, Bangkok, 3Department of Ophthalmology, Samut Prakan Hospital, Samut Prakan, Thailand; 4Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA Purpose: The purpose of this study was to evaluate the effect of pupillary dilation on the Haigis formula-calculated intraocular lens (IOL power and ocular biometry measurements by using IOLMaster®. Methods: A prospective study was performed for biometry measurements of 373 eyes of 192 healthy subjects using the IOLMaster at the outpatient department of King Chulalongkorn Memorial Hospital from February 2013 to July 2013. The axial length (AL, anterior chamber depth (ACD, keratometry (K, and IOL power were measured before and after 1% tropicamide eye drop instillation. The Haigis formula was used in the IOL power calculation with the predicted target to emmetropia. Each parameter was compared by a paired t-test prior to and after pupillary dilation. Bland–Altman plots were also used to determine the agreement between each parameter. Results: The mean age of the subjects was 53.74±14.41 years (range 18–93 years. No differences in AL (P=0.03, steepest K (P=0.42, and flattest K (P=0.41 were obtained from the IOLMaster after pupillary dilation. However, ACD and IOL power were significantly different postdilation (P<0.01 and P<0.01, respectively. In ACD and IOL power measurements, the concordance rates were 93.03% and 97.05% within 95% limits of agreement (-0.48 to 0.26 mm and -1.09 to 0.88 D, respectively in the Bland–Altman plots. Conclusion: Biometry measurements in the cycloplegic stage should be considered in the IOL formulas that use parameters other than AL and K. Keywords: Haigis

  11. Correlations between refractive error and biometric parameters in human eyes using the LenStar 900.

    Science.gov (United States)

    O'Donnell, Clare; Hartwig, Andreas; Radhakrishnan, Hema

    2011-02-01

    To investigate the relationship between refractive error and ocular biometry in healthy subjects using a new optical low coherence reflectometry device. Biometric measurements were obtained with a LenStar LS 900 (Haag Streit, Switzerland) on one eye of 70 phakic subjects (mean ± SD age; 29 ± 9 years). Forty myopes and 30 non-myopes (best sphere range -9.63 D to +0.63 D) were included. Outcome measures were compared for the two groups using one way between groups ANOVA. These included; keratometry, central corneal thickness, iris width, anterior chamber depth, pupil diameter, lens thickness, axial length and retinal thickness. No mydriatic or cycloplegic agents were used. There were significant differences between groups for keratometry readings (p = 0.021 and p = 0.038 for steep and flat k readings respectively), anterior chamber depth (p = 0.001), lens thickness (p = 0.026) and axial length (pbiometric parameters assessed and provides information about the relationships between these biometric parameters and age. The results, coupled with a unique ability to image and analyse the ocular structures non-invasively make the LenStar a promising new instrument for ocular evaluation in research and clinical practice. Copyright © 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  12. Simultaneous measurement of refractive index and thickness distributions using low-coherence digital holography and vertical scanning

    International Nuclear Information System (INIS)

    Watanabe, Kaho; Ohshima, Masashi; Nomura, Takanori

    2014-01-01

    The simultaneous measurement method of a refractive index distribution and a thickness distribution using low-coherence digital holography with a vertical scanning is proposed. The proposed method consists of a combination of digital holography and low-coherence interferometry. The introduction of a datum plane enables the measurement of both a refractive index distribution and a thickness distribution. By the optical experiment, the potential of the proposed method is confirmed. (paper)

  13. Direct measurements of the velocity and thickness of ''explosively'' propagating buried molten layers in amorphous silicon

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Jellison, G.E. Jr.; Pennycook, S.J.; Withrow, S.P.; Mashburn, D.N.

    1986-01-01

    Simultaneous infrared (1152 nm) and visible (633 nm) reflectivity measurements with nanosecond resolution were used to study the initial formation and subsequent motion of pulsed KrF laser-induced ''explosively'' propagating buried molten layers in ion implantation-amorphized silicon. The buried layer velocity decreases with depth below the surface, but increases with KrF laser energy density; a maximum velocity of about 14 m/s was observed, implying an undercooling-velocity relationship of approx. 14 K/(m/s). Z-contrast scanning transmission electron microscopy was used to form a direct chemical image of implanted Cu ions transported by the buried layer and showed that the final buried layer thickness was <15 nm

  14. Comparison of aerosol optical thickness retrieval from spectroradiometer measurements and from two radiative transfer models

    Energy Technology Data Exchange (ETDEWEB)

    Utrillas, M.P.; Martinez-Lozano, J.A.; Tena, F. [Universitat de Valencia, Dept. de Termodinamica, Valencia (Spain); Cachorro, V.E. [Universidad de Valladolid, Dept. de Fisica Aplicada 1, Valladolid (Spain); Hernandez, S. [Universidad de Valladolid, Dept. de Ingenieria Agricola y Forestal, Valladolid (Spain)

    2000-07-01

    The spectral values of the aerosol optical thickness {tau}{sub a{lambda}} in the 400-670 nm band have been determined from 500 solar direct irradiance spectra at normal incidence registered at Valencia (Spain) in the period from July 1993 to March 1997. The {tau}{sub a{lambda}} values obtained from experimental measurements have been compared with the boundary layer aerosol models implemented in the radiative transfer codes ZD-LOA and LOWTRAN 7. For the ZD-LOA code, the continental and maritime models have been considered and for the LOWTRAN 7 code the rural, maritime, urban and tropospheric models have been used. The obtained results show that the aerosol model that best represents the average turbidity of the boundary layer for the urban area of Valencia (Spain) is the continental model when the ZD-LOA code is used and the urban model when the LOWTRAN 7 code is used. (Author)

  15. Eddy current NDT: a suitable tool to measure oxide layer thickness in PWR fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Alencar, Donizete A.; Silva Junior, Silverio F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)], e-mail: daa@cdtn.br, e-mail: silvasf@cdtn.br; Vieira, Andre L.P.S. [Industrias Nucleares do Brasil (INB S.A.), Resende, RJ (Brazil). Fabrica de Combustivel Nuclear], e-mail: andre@inb.gov.br; Soares, Adolpho [Technotest Consultoria e Acessoria Ltda., Belo Horizonte, MG (Brazil)], e-mail: adolpho@technotest.com.br

    2009-07-01

    Eddy current is a nondestructive test (NDT) widely used in industry to support integrity analysis of components and equipment. In the nuclear area it is frequently applied to inspect tubes installed in tube exchangers, such as steam generators and condensers in PWR plants, as well as turbine blades. Adequately assisted by means of robotic devices, that inspection method has been pointed as a suitable tool to perform accurate oxide layer thickness measurements in PWR fuel rods. This paper shows some theoretical aspects and physical operating principles of the inspection method, as well as test probes construction details, and the calibration reference standards fabrication processes. Furthermore, some data, experimentally obtained at INB laboratories and other technical information obtained from TECNATOM S.A. are presented, showing the accuracy and efficacy of such NDT method. (author)

  16. Eddy current NDT: a suitable tool to measure oxide layer thickness in PWR fuel rods

    International Nuclear Information System (INIS)

    Alencar, Donizete A.; Silva Junior, Silverio F.; Vieira, Andre L.P.S.

    2009-01-01

    Eddy current is a nondestructive test (NDT) widely used in industry to support integrity analysis of components and equipment. In the nuclear area it is frequently applied to inspect tubes installed in tube exchangers, such as steam generators and condensers in PWR plants, as well as turbine blades. Adequately assisted by means of robotic devices, that inspection method has been pointed as a suitable tool to perform accurate oxide layer thickness measurements in PWR fuel rods. This paper shows some theoretical aspects and physical operating principles of the inspection method, as well as test probes construction details, and the calibration reference standards fabrication processes. Furthermore, some data, experimentally obtained at INB laboratories and other technical information obtained from TECNATOM S.A. are presented, showing the accuracy and efficacy of such NDT method. (author)

  17. Comparison of central corneal thickness in dogs measured by ultrasound pachymetry and ultrasound biomicroscopy.

    Science.gov (United States)

    Martín-Suárez, Eva; Galán, Alba; Morgaz, Juan; Guisado, Alicia; Gallardo, José María; Gómez-Villamandos, Rafael Jesús

    2018-02-01

    Ultrasound pachymetry (UP) is currently the most common technique used to evaluate central corneal thickness (CCT). New devices which allow assessment of CCT without corneal contact have been compared, but there are discrepancies among instruments. The aim of this study was to compare CCT measurements obtained by UP and ultrasound biomicroscopy (UBM) in 28 eyes of 14 healthy Beagles dogs. Mean CCT±standard deviation (SD) were 552±63μm for UP and 551±55μm for UBM. UBM showed both a fixed and proportional bias when compared to ultrasound pachymetry, but this was not considered to be clinically important. Measured CCT did not differ between UP and UBM (P=0.796). The intra-class correlation coefficient indicated a strong agreement between methods (0.990). The CCT measurements between left (548±61μm) and right (555±59μm) eyes did not differ (P=0.760). Male dogs had higher CCT measurements than female dogs (P=0.038). Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Correlation between Central Corneal Thickness and Intraocular Pressure Measured by Goldmann Applanation Tonometry or Pascal Dynamic Contour Tonometry.

    Science.gov (United States)

    Katsimpris, J M; Theoulakis, P E; Vasilopoulos, K; Skourtis, G; Papadopoulos, G E; Petropoulos, I K

    2015-04-01

    The aim of this study was to investigate the relationship between central corneal thickness and intraocular pressure measured by Goldmann applanation tonometry and Pascal dynamic contour tonometry. The study included 45 persons (90 eyes), divided into 4 groups: a) 10 normal volunteers (20 eyes); b) 16 patients (32 eyes) with primary open-angle glaucoma; c) 8 patients (16 eyes) with normal-tension glaucoma; and d) 11 patients (22 eyes) with ocular hypertension. Intraocular pressure was measured by Goldmann applanation tonometry and Pascal dynamic contour tonometry, and central corneal thickness was measured by ultrasound pachymetry. The relationship between intraocular pressure and central corneal thickness was evaluated. Intraocular pressure was correlated positively but not strongly enough with central corneal thickness when it was measured by Goldmann applanation tonometry. On the contrary, there was no correlation between intraocular pressure and central corneal thickness when intraocular pressure was measured by Pascal dynamic contour tonometry. Central corneal thickness is an important variable in the evaluation of intraocular pressure by Goldmann applanation tonometry. This factor does not interfere with the intraocular pressure measurements taken by Pascal dynamic contour tonometry. Georg Thieme Verlag KG Stuttgart · New York.

  19. Comparison of central corneal thickness measured by Lenstar LS900, OrbscanⅡ and ultrasonic pachmetry

    Directory of Open Access Journals (Sweden)

    Hong-Tao Zhang

    2013-09-01

    Full Text Available AIM: To investigate the difference of central corneal thickness(CCTmeasured by Lenstar LS900, OrbscahⅡ system and ultrasonic pachmetry, and to evaluate the correlation and consistency of the results for providing a theoretical basis for clinical application.METHODS: The mean value of CCT in 70 eyes of 35 patients measured three times by Lenstar LS900, OrbscahⅡ system and ultrasonic pachmetry underwent statistical analysis. The difference of CCT was compared, and the correlation and consistency of three measurements were analyzed to provide theoretical basis for clinical application. CCT values measured by different methods were analyzed with randomized block variance analysis. LSD-t test was used for pairwise comparison between groups. The correlation of three measurement methods were analyzed by linear correlation analysis, and Bland-Altman was used to analyze the consistency.RESULTS: The mean CCT values measured by Lenstar LS900, OrbscanⅡ and ultrasonic pachmetry were 542.75±40.06, 528.74±39.59, 538.54±40.93μm, respectively. The mean difference of CCT measurement was 4.21±8.78μm between Lenstar LS900 and ultrasonic pachmetry, 14.01±13.39μm between Lenstar LS900 and Orbscan Ⅱ, 9.8±10.57μm between ultrasonic pachmetry and Orbscan Ⅱ. The difference was statistically significant(PP>0.05: There was positive correlation between CCT with Lenstar LS900 and ultrasonic pachmetry(r=0.977, 0.944; PCONCLUSION: There are excellent correlation among Lenstar LS900, Orbscan Ⅱ and ultrasonic pachmetry. Lenstar LS900 can be used as CCT non-contact measurement tool.

  20. Ultrasonic measurements on residual stress in autofrettged thick walled petroleum pipes

    International Nuclear Information System (INIS)

    Woias, G.; Mizera, J.

    2008-01-01

    The residual stresses in a component or structure are caused by incompatible permanent deformation and related gradient of plastic/elastic strains. They may be generated or modified at every stage in the components life cycle, from original material production to final disposal. Residual stresses can be measured by non-destructive techniques, including X-ray and neutron diffraction, magnetic and ultrasonic methods. The selection of the optimum measurement technique should take account volumetric resolution, material, geometry and access to the component. For large metallic components neutron diffraction is of prime importance as it provides quantitative information on stresses in relatively large volume of methods disregarding its shape complexity. Residual stresses can play a significant role in explaining or preventing failure of components of industrial installations. One example of residual stresses preventing failure are the ones generated by shot peening, inducing surface compressive stresses that improve the fatigue life. Petroleum refinery piping is generally characterized by large-diameters, operated at elevated temperature and under high pressure. Pipelines of a polyethylene plant working in one of the Polish refineries are subjected to pressures exceeding 300 MPa at temperatures above 200 o C. The pipes considered here were pressurized with pressure of 600 MPa. The wall thickness of the pipes is 27 mm and pipe dimensions are 46 x 100 mm. The material is steel with Re=580 MPa. Due to pressurizing, the components retain compressive stresses at the internal surface. These stresses increase resistance to cracking of the pipes. Over the period of exploitation these stresses diminish due to temperature activated relaxation or creep. The purpose of the project is to verify kinetics of such a relaxation process and calibrate alternative methods of their measurements. To avoid stress relaxation, numerical analysis from Finite Element Modelling (FEM)gave an

  1. Can the SENSIMED Triggerfish®lens data be used as an accurate measure of intraocular pressure?

    Science.gov (United States)

    Vitish-Sharma, Parveen; Acheson, Austin G; Stead, Richard; Sharp, John; Abbas, Ali; Hovan, Marta; Maxwell-Armstrong, Charles; Guo, Boliang; King, Anthony J

    2018-03-01

    The SENSIMED Triggerfish ® contact lens sensor (CLS) has an embedded micro-sensor that captures spontaneous circumferential changes at the corneoscleral junction and transmits them via an antenna to a device where these measurements are stored. During laparoscopic colorectal surgery, patients are placed in Trendelenburg position which has been shown to increase intraocular pressure (IOP). Laparoscopic colorectal surgery requires both pneumoperitoneum and Trendelenburg positioning; therefore, IOP can vary significantly. We aimed to assess whether circumferential changes in the corneoscleral area can be correlated to IOP changes measured using Tono-pen ® XL applanation tonometer during laparoscopic colorectal surgery. Patients undergoing laparoscopic colorectal resections were included. On the day of surgery, baseline IOP was taken and the SENSIMED Triggerfish ® CLS was then set up in one eye of the patient. During surgery (whilst under general anaesthetic), IOP measurements were taken in the contralateral eye using a Tono-pen ® XL applanation tonometer every hour and any time the table was moved to record the fluctuations of IOP during surgery and any association with position change. The timings of these readings were documented. Twenty patients were included in this study (six males, 14 females). Average age was 64.6 years (SD = 16.3). The fluctuation in IOP measured in the reference eye ranged between 6.3 and 46.7 mmHg. The mean correlation coefficient between CLS output measurements and these IOP measurements was r = 0.291 (95% CI). Our results showed a weak correlation between the SENSIMED Triggerfish ® CLS data output and IOP measurements taken using the Tono-pen ® XL applanation tonometer. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Design, construction and performance evaluation of the target tissue thickness measurement system in intraoperative radiotherapy for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, Mohammad Reza, E-mail: myazdani@aut.ac.ir [Faculty of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Setayeshi, Saeed, E-mail: setayesh@aut.ac.ir [Faculty of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Arabalibeik, Hossein, E-mail: arabalibeik@tums.ac.ir [Research Center for Biomedical Technology and Robotics (RCBTR), Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Akbari, Mohammad Esmaeil [Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2017-05-21

    Intraoperative electron radiation therapy (IOERT), which uses electron beams for irradiating the target directly during the surgery, has the advantage of delivering a homogeneous dose to a controlled layer of tissue. Since the dose falls off quickly below the target thickness, the underlying normal tissues are spared. In selecting the appropriate electron energy, the accuracy of the target tissue thickness measurement is critical. In contrast to other procedures applied in IOERT, the routine measurement method is considered to be completely traditional and approximate. In this work, a novel mechanism is proposed for measuring the target tissue thickness with an acceptable level of accuracy. An electronic system has been designed and manufactured with the capability of measuring the tissue thickness based on the recorded electron density under the target. The results indicated the possibility of thickness measurement with a maximum error of 2 mm for 91.35% of data. Aside from system limitation in estimating the thickness of 5 mm phantom, for 88.94% of data, maximum error is 1 mm.

  3. Design, construction and performance evaluation of the target tissue thickness measurement system in intraoperative radiotherapy for breast cancer

    Science.gov (United States)

    Yazdani, Mohammad Reza; Setayeshi, Saeed; Arabalibeik, Hossein; Akbari, Mohammad Esmaeil

    2017-05-01

    Intraoperative electron radiation therapy (IOERT), which uses electron beams for irradiating the target directly during the surgery, has the advantage of delivering a homogeneous dose to a controlled layer of tissue. Since the dose falls off quickly below the target thickness, the underlying normal tissues are spared. In selecting the appropriate electron energy, the accuracy of the target tissue thickness measurement is critical. In contrast to other procedures applied in IOERT, the routine measurement method is considered to be completely traditional and approximate. In this work, a novel mechanism is proposed for measuring the target tissue thickness with an acceptable level of accuracy. An electronic system has been designed and manufactured with the capability of measuring the tissue thickness based on the recorded electron density under the target. The results indicated the possibility of thickness measurement with a maximum error of 2 mm for 91.35% of data. Aside from system limitation in estimating the thickness of 5 mm phantom, for 88.94% of data, maximum error is 1 mm.

  4. Accuracy and repeatability of a new tono-pachymeter for measuring central corneal thickness.

    Science.gov (United States)

    Garcia-Resua, Carlos; Blanco, Antia; Miñones, Mercedes; Yebra-Pimentel, Eva; Jesus Giraldez, Maria

    2012-05-01

    The recently developed noncontact tonopachymeter Tonopachy NT-530 P provides intraocular pressure values corrected for central corneal thickness (CCT). The purpose of this study was to assess the accuracy and repeatability of its CCT measurements. The CCT measurements were obtained in 64 right eyes of 64 young healthy subjects using the Orbscan corneal topography system followed by the Tonopachy and then by ultrasound pachymetry (UP). Another sample of 31 subjects was used to test the repeatability of the tonopachy measurements in 2 separate sessions 1 week apart. To compare the tonometers and determine intersession repeatability for the tonopachymeter, differences in the readings provided by pairs of the instruments or obtained in the two sessions were plotted against mean differences. The hypothesis of zero bias was examined by a paired t-test. The coefficient of repeatability was calculated as the 95% limits of agreement (LoAs) of differences between the 2 sessions. Measurements made using the three instruments were significantly correlated (P<0.001). Mean CCTs (±SD) measured using the Tonopachy, Orbscan (acoustic factor set at 0.92) and ultrasound pachymeter were 530.42 ± 34.96, 526.73 ± 39.53, and 550.69 ± 37.26 μm, respectively. The differences between modalities (±95% LoAs) were -3.68 ± 24.36 for Orbscan versus Tonopachy, 20.66 ± 14.69 for UP versus Tonopachy, and 23.95 ± 24.21 for UP versus Orbscan. The coefficient of repeatability for the tonopachymeter was ±15.11 μm. The Tonopachy offers similar CCT measurements to those provided by conventional pachymeters with good repeatability.

  5. Precision of high definition spectral-domain optical coherence tomography for measuring central corneal thickness.

    Science.gov (United States)

    Correa-Pérez, María E; López-Miguel, Alberto; Miranda-Anta, Silvia; Iglesias-Cortiñas, Darío; Alió, Jorge L; Maldonado, Miguel J

    2012-04-06

    This study was intended to assess the reliability of central corneal thickness (CCT) measurements using Cirrus high-definition optical coherence tomography (HD-OCT) in healthy subjects and its accuracy compared with ultrasonic pachymetry. Seventy-seven consecutive subjects were recruited for evaluating repeatability, and agreement between two examiners. To analyze repeatability, one examiner measured 77 eyes four times in succession. To study agreement between two observers, a second independently trained examiner obtained another CCT measurement. We also measured eyes in a subgroup of 20 patients using standard ultrasonic pachymetry. Within-subject standard deviation (S(w)), coefficient of variation (CV), limits of agreement (LoA), and intraclass correlation coefficient (ICC) data were obtained. For repeatability, the S(w) and precision (1.96 × S(w)) were 4.86 and 9.52 μm, respectively. Intraobserver CV was 0.89% and the ICC was 0.98 (95% confidence interval [CI], 0.97-0.99). For agreement between two examiners, the S(w) and precision were 7.58 and 14.85 μm, respectively; the CV was 1.40%. The mean difference between observers was -0.13 μm (95% CI, -1.85 to 1.58; P = 0.87). The width of the LoA was 29.64 μm. Median difference between Cirrus HD-OCT and ultrasound CCT measurements was -4.5 μm (interquartile range, -7.0-0.0; P = 0.04). Cirrus HD-OCT provides repeatable CCT measurements, good agreement between two independently trained examiners, and its systematic bias compared to ultrasonic pachymetry is clinically negligible. Therefore, research laboratories and eye clinics using Cirrus HD-OCT as a diagnostic imaging method, can also benefit from a reliable noncontact pachymeter when counseling patients with glaucoma and those undergoing corneal and refractive surgeries.

  6. Accuracy of Cirrus HD-OCT and Topcon SP-3000P for measuring central corneal thickness.

    Science.gov (United States)

    Calvo-Sanz, Jorge A; Ruiz-Alcocer, Javier; Sánchez-Tena, Miguel A

    2017-02-18

    To compare and analyze the interchangeability of three measuring systems, each based on a different technique, for central corneal thickness (CCT) analysis. CCT measurements were measured using optical coherence tomography (OCT), non-contact specular microscopy (NCSM), and ultrasonic pachymetry (USP) in 60 eyes of 60 healthy patients with a mean age of 66.5±15.0 years and a mean spherical equivalent of 0.43±1.14 D. Analysis of variations in measurement concordance and correlation among the three different methods were performed. Comparison of CCT measurements were done using Bland-Altman plots (with bias and 95% confidence intervals), intraclass correlation coefficient (ICC), and paired t-student analysis. Mean CCT values were: 549.20±26.91μm for USP (range 503-618μm), 514.20±27.49μm for NCSM (range 456-586μm) and 542.80±25.56μm for OCT (range 486-605μm). CCT values obtained with NCMS were significantly lower than those obtained with OCT and USP methods. NCMS CCT value was 36.08±10.72μm lower than USP value (p<0.05), and NCMS CCT value was 7.88±8.86μm lower than OCT value (p<0.05). ICC between USP-NCSM pair was 0.488 and 0.909 between USP-OCT pair. OCT and UPS offered highly comparable results, whereas NCSM offered lower mean CCT values compared to the other two methods. Therefore, NCSM should not be considered a reliable method for measuring CCT and should rather be considered for assessing longitudinal changes in the same patient. Copyright © 2017 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  7. Prototype of a fiber optic sensor for online measurement of coating thickness

    Science.gov (United States)

    D'Emilia, Giulio

    1999-09-01

    In this paper the experimental characterization of a transducer for on line measurement of coating thickness in food industry applications is described, which is composed by a fiber optic probe and by an eddy-current proximity one. The method is based on measuring reflectance by a fiber optic probe of the coating plated on thin steel sheets. The eddy current proximity probe should be used to measure the substrate position. In order to evaluate the feasibility of this approach, a particular attention has been paid to the accuracy of the method, since an accuracy in the order of plus or minus 1 micrometer should be achieved for practical interest. With this aim, the effect of the main interfering and modifying quantities of geometrical (sensor size, probe head angle of incidence, working distance, ...) and optical (light source and photo-detector behavior stability, ...) type has been evaluated both theoretically and experimentally by using a calibration test bench in stationary working conditions. Furthermore, a calibration test bench has been built, where a translating and vibrating steel plate is realized, in order to evaluate the effect of translation velocity of the plate and also of cross vibrations. Results of dynamic calibration are also described and discussed, in order to get information about the final sensor configuration.

  8. Development method for measuring thickness of nuclei and coating of fuel plates

    International Nuclear Information System (INIS)

    Borges Junior, Reinaldo

    2013-01-01

    One of the most important components of a nuclear reactor is the Nuclear Fuel. Currently, the most advanced commercial fuel, whose applicability in Brazilian reactors has been developed by IPEN since 1985, is the silicide U 3 Si 2 . This is formed by fuel plates with nuclei dispersion (where the fissile material (U 3 Si 2 ) is homogeneously dispersed in a matrix of aluminum) coated aluminum. This fuel is produced in Brazil with developed technology, the result of the efforts made by the group of manufacturing nuclear fuel (CCN - Center of Nuclear Fuel) of IPEN. Considering the necessity of increasing the power of the IEA- R1 and Brazilian Multipurpose Reactor Building (RMB), for the production of radioisotopes - mainly for the area of medicine - there will be significant increase in the production of nuclear fuel at IPEN. Given this situation, if necessary, make the development of more modern and automated classification techniques. Aiming at this goal, this work developed a new computational method for measuring thickness of core and cladding of fuel plates, which are able to perform such measurements in less time and with more meaningful statistical data when compared with the current method of measurement. (author)

  9. Development of Wall-Thinning Evaluation Procedure for Nuclear Power Plant Piping—Part 1: Quantification of Thickness Measurement Deviation

    Directory of Open Access Journals (Sweden)

    Hun Yun

    2016-06-01

    Full Text Available Pipe wall thinning by flow-accelerated corrosion and various types of erosion is a significant and costly damage phenomenon in secondary piping systems of nuclear power plants (NPPs. Most NPPs have management programs to ensure pipe integrity due to wall thinning that includes periodic measurements for pipe wall thicknesses using nondestructive evaluation techniques. Numerous measurements using ultrasonic tests (UTs; one of the nondestructive evaluation technologies have been performed during scheduled outages in NPPs. Using the thickness measurement data, wall thinning rates of each component are determined conservatively according to several evaluation methods developed by the United States Electric Power Research Institute. However, little is known about the conservativeness or reliability of the evaluation methods because of a lack of understanding of the measurement error. In this study, quantitative models for UT thickness measurement deviations of nuclear pipes and fittings were developed as the first step for establishing an optimized thinning evaluation procedure considering measurement error. In order to understand the characteristics of UT thickness measurement errors of nuclear pipes and fittings, round robin test results, which were obtained by previous researchers under laboratory conditions, were analyzed. Then, based on a large dataset of actual plant data from four NPPs, a quantitative model for UT thickness measurement deviation is proposed for plant conditions.

  10. Through-Thickness Measurements of Residual Stresses in an Overlay Dissimilar Weld Pipe using Neutron Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Wan Chuck; EM, Vyacheslav; Lee, Ho Jin; Kim, Kang Soo; Kang, Mi Hyun; Joo, Jong Dae; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)

    2010-10-15

    The distribution of residual stresses in dissimilar material joints has been extensively studied because of the wide applications of the dissimilar welds in many inevitable complex design structures. Especially the cracking of dissimilar welding has been a long standing issue of importance in many components of the power generation industries such as nuclear power plant, boiling pressure system, and steam generators. In particular, several failure analysis and direct observations have shown that critical fractures have frequently occurred in one side of the dissimilar welded parts. For example, the heat-affected zone on the ferrite steel side is known to critical in many dissimilar welding pipes when ferrite (low carbon steel) and austenite (stainless) steels are joined. The main cause of the residual stresses can be attributed to the mismatch in the coefficient of thermal expansion between the dissimilar metals (ferrite and austenite). Additional cladding over circumferential welds is known to reinforce the mechanical property due to the beneficial compressive residual stress imposed on the weld and heat-affected zone. However, science-based quantitative measurement of the through thickness residual stress distribution is very limited in literature. The deep penetration capability of neutrons into most metallic materials makes neutron diffraction a powerful tool to investigate and map the residual stresses of materials throughout the thickness and across the weld. Furthermore, the unique volume averaged bulk characteristic of materials and mapping capability in three dimensions are suitable for the engineering purpose. Thus, the neutron-diffraction measurement method has been selected as the most useful method for the study of the residual stresses in various dissimilar metal welded structures. The purpose of this study is to measure the distribution of the residual stresses in a complex dissimilar joining with overlay in the weld pipe. Specifically, we measured

  11. Central corneal thickness and anterior chamber depth measurement by Sirius® Scheimpflug tomography and ultrasound

    Directory of Open Access Journals (Sweden)

    Jorge J

    2013-02-01

    Full Text Available J Jorge,1 JL Rosado,2 JA Díaz-Rey,1 JM González-Méijome11Clinical and Experimental Optometry Research Laboratory, Center of Physics (Optometry, School of Sciences, University of Minho, Braga, 2Opticlinic, Lisboa, PortugalBackground: The purpose of this study was to compare the accuracy of the new Sirius® Scheimpflug anterior segment examination device for measurement of central corneal thickness (CCT and anterior chamber depth (ACD with that of CCT measurements obtained by ultrasound pachymetry and ACD measurements obtained by ultrasound biometry, respectively.Methods: CCT and ACD was measured in 50 right eyes from 50 healthy subjects using a Sirius Scheimpflug camera, SP100 ultrasound pachymetry, and US800 ultrasound biometry.Results: CCT measured with the Sirius was 546 ± 39 µm and 541 ± 35 µm with SP100 ultrasound pachymetry (P = 0.003. The difference was statistically significant (mean difference 4.68 ± 10.5 µm; limits of agreement −15.8 to 25.20 µm. ACD measured with the Sirius was 2.96 ± 0.3 mm compared with 3.36 ± 0.29 mm using US800 ultrasound biometry (P < 0.001. The difference was statistically significant (mean difference −0.40 ± 0.16 mm; limits of agreement −0.72 to 0.07 mm. When the ACD values obtained using ultrasound biometry were corrected according to the values for CCT measured by ultrasound, the agreement increased significantly between both technologies for ACD measurements (mean difference 0.15 ± 0.16 mm; limits of agreement −0.16 to 0.45 mm.Conclusion: CCT and ACD measured by Sirius and ultrasound methods showing good agreement between repeated measurements obtained in the same subjects (repeatability with either instrument. However, CCT and ACD values, even after correcting ultrasound ACD by subtracting the CCT value obtained with either technology should not be used interchangeably.Keywords: Scheimpflug corneal tomography, ultrasound biometry, ultrasound pachymetry, limits of agreement

  12. An array of lens-coupled antennas for cosmic microwave background measurements in the 30 Ghz band

    Science.gov (United States)

    Colin, Angel; Ortiz, David; Villa, Enrique; Artal, Edurado; Martínez-González, Enrique

    2012-03-01

    An array of bow-tie slot antennas coupled through an extended hemispherical lens is proposed to operate in the 30 GHz frequency band. The design includes a combination of three microstrip Wilkinson power dividers (WPD) and transitions to coplanar wave guides (CPW) to form the feeding antenna network. This configuration is suitable for the integration with heterodyne imaging detectors commonly used in radioastronomy. Measurements and simulation results exhibit a frequency range of operation from 20 to 40 GHz with a bandwidth of 24% achieved for -10 dB return loss at the central frequency. The measured radiation patterns show a maximum peak gain of around 13 dB with HPBW of 10° for the E-plane, and whose first side lobes are lower than 13 dB below the main lobe in both angular shift sides. The presented results will be considered as preliminary feasibility studies in the 30 GHz QUIJOTE-CMB Instrument, which is designed to study the anisotropies of the Cosmic Microwave Background (CMB).

  13. Transabdominal ultrasound for standardized measurement of bowel wall thickness in normal children and those with Crohn's disease.

    Science.gov (United States)

    Chiorean, Liliana; Schreiber-Dietrich, Dagmar; Braden, Barbara; Cui, XinWu; Dietrich, Christoph F

    2014-12-01

    The intestinal wall can be visualized using high resolution transabdominal ultrasound (TUS). TTUS measurement of the bowel wall thickness has been described in adults but data are lacking in children. The purpose of this prospective study was to sonographically investigate bowel wall thickness in healthy children and children with Crohn's disease. TUS (5-15 MHz) of the intestine was performed in 58 healthy children (age range 3 to 16 years) and in 30 children with Crohn's disease (age range 8 to 17 years). The following regions were assessed and bowel wall thickness measured: terminal ileum, cecum, right flexure, and sigmoid colon. In patients with Crohn's disease, the involved region was additionally assessed regarding length of involved segment and sonographic signs of transmural inflammation and fistula. TUS allowed adequate measurement of bowel wall thickness in all 58 healthy children (100%) and in all 30 Crohn's disease patients (100%). The bowel wall thickness significantly differed between groups. Bowel wall thickness (mean +/- SD) in all segments was less then 2 mm in all healthy children (1.0+/-0.1 mm terminal ileum, 1.1+/-0.1 mm cecum, 1.1+/-0.1 mm right flexure, and 1.3+/-0.1 mm sigmoid colon). In Crohn's disease patients, bowel wall thickness was ≥ 3 mm in the ileocecal region and was significantly increased (5.1+/-1.9 mm) compared to the healthy children. The mean length of involved segment was 15+/-6.5 cm [5 - 30 cm]. Additional findings in Crohn's disease patients were: transmural inflamation (3/30), interenteric fistula (3/30), gastrocolic fistula (1/30) and vesicoenteric fistula (1/30). Similar to adults, normal bowel wall thickness in children is always less than 2 mm. In all patients with Crohn's disease, increased bowel wall thickness could be detected. TUS is a helpful tool in the diagnosis and assessment of activity and complications in Crohn's disease.

  14. Wet/dry film thickness measurement of paint by absorption spectroscopy with acousto-optic tunable filter spectrometer

    Science.gov (United States)

    Sinha, Pranay G.; Xiong, Xiangchun; Jin, Feng; Trivedi, Sudhir; Prasad, Narashima S.

    2005-08-01

    Controlling/monitoring the thickness of applied paint in real time is important to many situations including painting ship and submarine hulls in dry docks for maintaining health of ships and submarines against the harshness of the sea, in automobile and aerospace industries, and in a variety of other industries as a control sensor that plays significant role in product quality, process control, and cost control. Insufficient thickness results to inadequate protection while overspray leads to waste and pollution of the environment. A rugged instrumentation for the real time non-contact accurate measurement of wet and dry paint film thickness measurement will be immensely valuable. As paint is applied with several layers of the same or different type, thickness of each newly sprayed wet layer is of most interest, but measurement on dry paint is also useful. In this study, we use acousto-optic tunable filter-based near infrared spectrometer to obtain the absorption spectrum of layers of paint sprayed on sand blasted steel surface and thus measure the thickness of coating under both wet and dry situations. NIR spectra are obtained from 1100 to 2300 nm on four sample of different thickness of paint up to 127 micron. Partial least squares model built with the spectra shows good correlation with standard error of prediction within ~ 0.7 micron. Results indicate that the spectra also respond to the amount of organic solvent in the wet paint and can be used to monitor the degree of dryness of the paint in real time.

  15. Design of instantaneous liquid film thickness measurement system for conductive or non-conductive fluid with high viscosity

    Directory of Open Access Journals (Sweden)

    Yongxin Yu

    2017-06-01

    Full Text Available In the paper, a new capacitive sensor with a dielectric film coating was designed to measure the thickness of the liquid film on a flat surface. The measured medium can be conductive or non-conductive fluid with high viscosity such as silicone oil, syrup, CMC solution and melt. With the dielectric film coating, the defects caused by the humidity in a capacitor can be avoided completely. With a excitation frequency 0-20kHz, the static permittivity of capacitive sensor is obtained and stable when small thicknesses are monitored within the frequency of 0-3kHz. Based on the measurement principle, an experimental system was designed and verified including calibration and actual measurement for different liquid film thickness. Experimental results showed that the sensitivity, the resolution, repeatability and linear range of the capacitive sensor are satisfied to the liquid film thickness measurement. Finally, the capacitive measuring system was successfully applied to the water, silicone oil and syrup film thickness measurement.

  16. Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

    International Nuclear Information System (INIS)

    Reinhard, Benjamin; Schmitt, Klemens M.; Neu, Jens; Wollrab, Viktoria; Beigang, Rene; Rahm, Marco

    2012-01-01

    We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16 000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.

  17. Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Reinhard, Benjamin; Schmitt, Klemens M.; Neu, Jens [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Wollrab, Viktoria; Beigang, Rene; Rahm, Marco [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern (Germany); Fraunhofer Institute for Physical Measurement Techniques IPM, 79110 Freiburg (Germany)

    2012-05-28

    We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16 000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.

  18. Measurements of Linac4 H$^{-}$ ion source beam with a magnetized Einzel lens electron dump

    CERN Document Server

    Midttun, O; Scrivens, R

    2014-01-01

    Linac4 is a part of the upgrade of CERN’s accelerator complex for increased luminosity in the LHC. A new system to extract the ion beam from the plasma generator has been designed and tested, in order to improve the reliability and beam optics of the pulsed H- ion source. This paper presents the successfully implemented extraction system and three different beam measurements. The simulations compare well to the measurements and show that the plasma density was too low for the extraction system design during the measurements.

  19. External abdominal oblique muscle ultrasonographic thickness changes is not an appropriate surrogate measure of electromyographic activity during isometric trunk contractions.

    Science.gov (United States)

    Rabello, Lucas M; Gagnon, Dany; da Silva, Rubens A; Paquette, Philippe; Larivière, Christian

    2015-01-01

    The function of specific abdominal muscles can be assessed using both electromyography (EMG) and ultrasound imaging (USI) thickness measures. However, the relationship between these two measurements is not conclusive during sitting isometric trunk efforts. This study was conducted to assess the relationship between USI thickness and EMG amplitude measures of the right external oblique (EO) muscle during isometric efforts in the sitting position. Eighteen subjects performed ramp isometric efforts progressing from 0 to 50% of their maximal voluntary contraction (MVC) in three trunk directions on a dynamometer: (1) forward flexion; (2) right lateral flexion; and (3) left axial rotation. USI and surface EMG amplitude measures of the EO muscle were recorded concomitantly and both normalized against rest values and maximal EMG, respectively. EO muscle was significantly more activated (p muscle activity. USI thickness measures should be interpreted with great caution in research and clinical settings.

  20. Effects of lens distortion calibration patterns on the accuracy of monocular 3D measurements

    CSIR Research Space (South Africa)

    De Villiers, J

    2011-11-01

    Full Text Available unified and objective manner. A common image dataset is captured along with physical measurements and is used to quantify the photogrammetric accuracy of the different calibration techniques. Multiple calibration patterns and sizes are tested and compared...

  1. Subfoveal choroidal thickness measured by Cirrus HD optical coherence tomography in myopia

    Directory of Open Access Journals (Sweden)

    Li-Li Chen

    2014-09-01

    Full Text Available ATM: To measure the subfoveal choroidal thickness(SFCTin myopia using Cirrus HD optical coherence tomography(OCT, and to explore the relationship between the SFCT, axial length and myopic refractive spherical equivalent.METHODS: One-hundred thirty-three eyes of 70 healthy volunteers were recruited, and were divided into emmetropia group, low-degree myopia, middle-degree myopia and high-degree myopia group. SFCT were measured by Cirrus HD OCT, and the relationship between the SFCT, axial length and myopic refractive spherical equivalent were evaluated.RESULTS: 1Average SFCT was(275.91±55.74μm in normals, that in emmetropia group, low-degree myopia, middle-degree myopia and high-degree myopia group were(290.03±34.82μm,(287.64±51.51μm,(274.95±56.83μm,(248.37±67.98μm; 2the SFCT of high-degree myopia group was significant thinner than that of emmetropia group(PPPCONCLUSION: the SFCT is inversely correlated with increasing axial length and myopic refractive error.

  2. Genetic network properties of the human cortex based on regional thickness and surface area measures

    Directory of Open Access Journals (Sweden)

    Anna R. Docherty

    2015-08-01

    Full Text Available We examined network properties of genetic covariance between average cortical thickness (CT and surface area (SA within genetically-identified cortical parcellations that we previously derived from human cortical genetic maps using vertex-wise fuzzy clustering analysis with high spatial resolution. There were 24 hierarchical parcellations based on vertex-wise CT and 24 based on vertex-wise SA expansion/contraction; in both cases the 12 parcellations per hemisphere were largely symmetrical. We utilized three techniques—biometrical genetic modeling, cluster analysis, and graph theory—to examine genetic relationships and network properties within and between the 48 parcellation measures. Biometrical modeling indicated significant shared genetic covariance between size of several of the genetic parcellations. Cluster analysis suggested small distinct groupings of genetic covariance; networks highlighted several significant negative and positive genetic correlations between bilateral parcellations. Graph theoretical analysis suggested that small world, but not rich club, network properties may characterize the genetic relationships between these regional size measures. These findings suggest that cortical genetic parcellations exhibit short characteristic path lengths across a broad network of connections. This property may be protective against network failure. In contrast, previous research with structural data has observed strong rich club properties with tightly interconnected hub networks. Future studies of these genetic networks might provide powerful phenotypes for genetic studies of normal and pathological brain development, aging, and function.

  3. Measurement of the thickness of the sprayed nickel coatings on large-sized cast iron products

    Directory of Open Access Journals (Sweden)

    В. А. Сясько

    2016-11-01

    Full Text Available Modern industries increasingly use automatic spraying of heat-resistant Nickel  coating with a thickness  of      T = 1-3 mm for large-size parts made of cast iron with nodular graphite. The process of coating application is characterized by time-dependent behavior of its relative magnetic permeability, μс , that is a function of relaxation time, which can be as long as 24 hours, and by μс deviation from point to point on the surface. Aspects of eddy-current phase method for measuring the T value are considered. The structure of four- winding eddy current transformer transducers is described and results of calculation and optimization of their parameters are presented. The influence of controlled and interfering parameters is considered. Based  on the above results, a two-channel combined transducer is developed  providing measurement  error  of ΔТ ≤ ±(0.03T + 0.02 mm  in the shop environment in the process of coating application and in the final product check. Results of tests on reference specimens and of application in production processes are presented.

  4. Automated scheme for measuring mandibular cortical thickness on dental panoramic radiographs for osteoporosis screening

    Science.gov (United States)

    Matsumoto, T.; Hayashi, T.; Hara, T.; Katsumata, A.; Muramatsu, C.; Zhou, X.; Iida, Y.; Matsuoka, M.; Katagi, Ki.; Fujita, H.

    2012-03-01

    Findings of dental panoramic radiographs (DPRs) have shown that the mandibular cortical thickness (MCT) was significantly correlated with osteoporosis. Identifying asymptomatic patients with osteoporosis through dental examinations may bring a supplemental benefit for the patients. However, most of the DPRs are used for only diagnosing dental conditions by dentists in their routine clinical work. The aim of this study was to develop a computeraided diagnosis scheme that automatically measures MCT to assist dentists in screening osteoporosis. First, the inferior border of mandibular bone was detected by use of an active contour method. Second, the locations of mental foramina were estimated on the basis of the inferior border of mandibular bone. Finally, MCT was measured on the basis of the grayscale profile analysis. One hundred DPRs were used to evaluate our proposed scheme. Experimental results showed that the sensitivity and specificity for identifying osteoporotic patients were 92.6 % and 100 %, respectively. We conducted multiclinic trials, in which 223 cases have been obtained and processed in about a month. Our scheme succeeded in detecting all cases of suspected osteoporosis. Therefore, our scheme may have a potential to identify osteoporotic patients at an early stage.

  5. Is local stiffness, as measured by radio frequency, more sensitive than intima-media thickness?

    Science.gov (United States)

    Novo, G; Di Miceli, R; Novo, S

    2013-12-01

    The aim of our study was to explore the changes in common carotid arterial intima-media thickness (CCA IMT) and local arterial stiffness to evaluate, non-invasively, early vascular disease in patients with cardiovascular (CV) risk factors and "normal" carotid IMT (local stiffness with Quality Arterial Stiffness technology, based on Radio frequency signal (RFQAS-ESAOTE, Italy). CCA distensibility coefficient (DC), compliance coefficient (CC), pulse wave velocity (PWV) and β parameter were measured in patients, with and without traditional cardiovascular risk factors. 25 subjects with risk factors (mean age 49±13) were compared with 25 controls (mean age 36±12). We did not find any significant differences in the IMT measurement between subjects with CV risk factors compared to controls (0.530±0.99 mm vs. 0.626±0.127 mm; P=5.68). The mean DC (0.030±0.014 1/kPa vs. 0.0221±0.016 1/kPa; P6.05 m/s better identified, among patients with IMT <0.9 mm, those with cardiovascular risk factors (sensitivity 82.0% specificity 62.0%; AUC 0.73). Increased stiffness is a result of change both in quantity and quality of the arterial wall. Arterial functional changes and distention alterations may herald the onset of vascular disease before manifestation of symptoms or detection of preclinical atherosclerotic lesions.

  6. Pulse and vital sign measurement in mixed reality using a HoloLens

    OpenAIRE

    Mcduff , Daniel; Hurter , Christophe; Gonzalez-Franco , Mar

    2017-01-01

    International audience; Cardiography, quantitative measurement of the functioning of the heart, traditionally requires customized obtrusive contact sensors. Using new methods photoplethysmography and ballistocardiography signals can be captured using ubiquitous sensors, such as webcams and accelerometers. However, these signals are not visible to the unaided eye. We present Cardiolens-a mixed reality system that enables real-time, hands-free measurement and visu-alization of blood ow and vita...

  7. Lens or Prism? Patent Citations as a Measure of Knowledge Flows from Public Research

    Science.gov (United States)

    Roach, Michael; Cohen, Wesley M.

    2013-01-01

    This paper assesses the validity and accuracy of firms’ backward patent citations as a measure of knowledge flows from public research by employing a newly constructed dataset that matches patents to survey data at the level of the R&D lab. Using survey-based measures of the dimensions of knowledge flows, we identify sources of systematic measurement error associated with backward citations to both patent and nonpatent references. We find that patent citations reflect the codified knowledge flows from public research, but they appear to miss knowledge flows that are more private and contract-based in nature, as well as those used in firm basic research. We also find that firms’ patenting and citing strategies affect patent citations, making citations less indicative of knowledge flows. In addition, an illustrative analysis examining the magnitude and direction of measurement error bias suggests that measuring knowledge flows with patent citations can lead to substantial underestimation of the effect of public research on firms’ innovative performance. Throughout our analyses we find that nonpatent references (e.g., journals, conferences, etc.), not the more commonly used patent references, are a better measure of knowledge originating from public research. PMID:24470690

  8. Variability of automated carotid intima-media thickness measurements by novice operators.

    Science.gov (United States)

    Nichols, S; Milner, M; Meijer, R; Carroll, S; Ingle, L

    2016-01-01

    Carotid intima-media thickness (C-IMT) measurements provide a non-invasive assessment of subclinical atherosclerosis. The aim of the study was to assess the inter- and intra-observer variability of automated C-IMT measurements undertaken by two novice operators using the Panasonic CardioHealth Station. Participants were free from cardio-metabolic disease, and each underwent serial bilateral C-IMT ultrasound measurements. Immediate interoperator measurement variability was calculated by comparing initial measurements taken by two operators. Immediate retest variability was calculated from two consecutive measurements and longer term variability was assessed by conducting a further scan 1 week later. Fifty apparently healthy participants (n = 20 females), aged 26·2 ± 5·0 years, were recruited. Operator 1 recorded a median (interquartile range) right and left-sided C-IMT of 0·471 mm (0·072 mm) and 0·462 mm (0·047 mm). Female's right and left C-IMT were 0·442 mm (0·049 mm) and 0·451 mm (0·063 mm), respectively. The limits of agreement (LoA) for immediate interoperator variability were -0·063 to 0·056 mm (mean bias -0·003 mm). Operator 1's immediate retest intra-operator LoA were -0·057 to 0·046 mm (mean bias was -0·005 mm). One-week LoA were -0·057 to 0·050 mm (mean bias -0·003 mm). Operator 2 recorded median right and left-sided C-IMT of 0·467 mm (0·089 mm) and 0·458 mm (0·046 mm) for males, respectively, whilst female measurements were 0·441 mm (0·052 mm) and 0·444 mm (0·054 mm), respectively. Operator 2's intra-operator immediate retest LoA were -0·056 to 0·056 (mean bias bias 0·008 mm). Novice operators produce acceptable short-term and 1-week inter- and intra-operator C-IMT measurement variability in healthy, young to middle-aged adults using the Panasonic CardioHealth Station. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  9. Thickness measurement of CIRUS calandria tubes by eddy-current method

    International Nuclear Information System (INIS)

    Gupta, S.K.; Chaudhuri, H.; Prasad, Radhika

    1975-01-01

    To plan the replacement of the calandria of CIRUS reactor, it is necessary to check the magnitude of reduction that has taken place in the thickness of the tubes. For the purpose, an instrument has been developed which can sense thickness reduction to a maximum extent of 20 thou. (author)

  10. Ultrasonic measurement of through-thickness stress gradients in textured sheet metals

    International Nuclear Information System (INIS)

    Man Chising; Li Jianbo; Fan Xingyan; Lu Weiyang

    2000-01-01

    The objective of this investigation is to explore the possibility of using the dispersion of high-frequency Rayleigh waves for the evaluation of through-thickness stress gradients at the surface of metal sheets. We consider an orthorhombic sheet of cubic metal with through-thickness inhomogeneities in stress and texture, and adopt a coordinate system under which the rolling (RD), transverse (TD), and normal direction (ND) of the sheet are taken as the 1-, 2-, and 3-direction, respectively. We restrict our attention to the special case where only the stress components T 11 (x 3 ) and T 22 (x 3 ) in the sheet are nonzero, and consider only Rayleigh waves of sufficiently high frequency for which the sheet can be taken as the half-space x 3 ≥0. For Rayleigh waves of two different frequencies (with wave numbers k 1 and k k 2 respectively) propagating on the same wave path along either RD or TD, we appeal to an analysis of J. Li and Man to obtain a high-frequency asymptotic formula which gives the relative change in time-of-flight Δt/t 0 as (1/k 1 -1/k 2 ) times a linear combination of the derivatives T 11 ' (0), T 22 ' (0), W 4m0 ' (0)(m=0,2,4) and W 6m0 (0)(m=0,2,4,6) at the surface are ascertained and the material constants in the acoustoelastic consitutive equation of this polycrystal are known. An experiment was performed on an AA7075-T651 aluminum alloy beam, in which Δt/t 0 was measured for various values of T 11 (0) and T 11 ' (0) produced by beam bending (with (T 22 ≡0). The relevant texture coefficients of the beam were measured by X-ray diffraction. To obtain specific predictions from the aforementioned symptotic formula, we replace the material constants of the sample by their counterparts predicted for polycrystalline (pure) aluminum by the Man-Paroni model. The predictions and Δt/t 0 are then compared with the experimental results

  11. Wall Thickness Measurement Of Insulated Pipe By Tangential Radiography Technique Using Ir 192

    International Nuclear Information System (INIS)

    Soedarjo

    2000-01-01

    Insulation pipe wall thickness by tangential radiography technique has been carried out using 41 Curie Iridium 192 source has activity for two carbon steel pipes. The outer diameter of the first pipe is 90 mm, wall thickness is 75.0 mm, source film film distance is 609.5 mm, source tangential point of insulation is 489.5 mm and exposure time 3 minute and 25 second. From the calculation, the first pipe thickness is found to be 12.54 mm and for the second pipe is 8.42 mm. The thickness is due to inaccuracy in reading the pipe thickness on radiography film and the geometry distortion radiation path

  12. Study of the structure of buffalo's eye lens and scleroretinal rim in Tabriz by ultrasonography

    Directory of Open Access Journals (Sweden)

    GH Assadnassab

    2011-05-01

    Full Text Available In this study, ultrasonographic condition of lens and posterior wall of buffalo's eye in Tabriz area were investigated due to their important role in vision and also measurements were made in anterior-posterior axial B-mode display methods. The ultrasonographic images were similar to the images obtained from other particularly the cow. Total thickness of the lens was 1.133 ± 0.052 cm with the thickness being 1.135 ± 0.052 cm in the right eye and 1.132 ± 0.053 cm in the left eye. Thickness of the posterior wall of the right and left eyes were 1.677 ± 0.042 mm and 1.672 ± 0.041 mm respectively with the total thickness of the posterior wall measuring 1.674 ± 0.040 mm. There was no significant difference between the left and right eyes regarding these parameters.

  13. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...

  14. Shielding effect of lead glasses on radiologists' eye lens exposure in interventional procedures

    International Nuclear Information System (INIS)

    Hu, Panpan; Kong, Yan; Chen, Bo; Liu, Qianqian; Zhuo, Weihai; Liu, Haikuan

    2017-01-01

    To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm 2 -sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm 2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm 2 per glass) lens are recommended (authors)

  15. Aerosol Optical Thicknesses Derived from Direct Solar Radiance Measurements between 350 and 2200 nm during CLAMS

    Science.gov (United States)

    Rodriguez, W. J.; Schuster, G.; Rutledge, K.; Holben, B.

    2002-05-01

    Aerosol Optical Thicknesses (AOT) were derived for the period of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign using direct solar radiance measurements. The CLAMS field campaign aims to assist the validation of Earth Observing System (EOS) data products and provide a more accurate description of the shortwave radiation budget in a cloud-free earth-atmosphere system. A commercially available spectroradiometer capable of measuring solar irradiances from 350 to 2500 nm at spectral intervals of 1 nm and time intervals as low as one second was utilized. This spectroradiometer is capable of providing direct solar radiances of 92 percent of the solar spectrum every second offering a dramatic increase in the amount of spectral and temporal information as compared to the conventionally used filter-based radiometers. This wealth of information could be utilized to monitor rapid variations in aerosol optical properties and other atmospheric species, e.g. water vapor. High altitude radiometric calibrations were performed prior to CLAMS to ensure the accuracy of the data. Results from this instrument as compared with a thoroughly calibrated and tested filtered-based instrument show good agreement in the days of interest. On July 17, 2001, the day where all the parties involved in the mission (satellite, airplane, and ground) acquired exceptional data, AOTs show values fluctuating from 0.49 to 0.44 at 500 nm and from 0.1 to .08 at 1020 nm. Alpha values derived for the visible wavelength range steadily increased throughout morning from 2.0 to 2.4 consistent with the presence of aerosols from continental air masses. The aerosol optical properties derived from this instrument are being utilized to validate and complement aircraft and satellite instrument data in the context of the CLAMS mission.

  16. New developments in the analysis and measurement of thicknesses by excitation of the fluorescent lines by means of β particles

    International Nuclear Information System (INIS)

    Martinelli, P.

    1960-01-01

    The process for analysing and measuring the thickness of deposits by β-X fluorescence which we have already described has undergone further development. The use of promethium-147 and krypton-85 sources makes it possible to reduce the background noise which is observed with strontium-90. We present the results obtained for various measurements of the thickness of metallic coatings and the continuous measurement of calcium and of iron in ore samples. We describe the tests carried out with a view to analysing the X-rays by means of a crystal. (author) [fr

  17. Free radially expanding liquid sheet in air: time- and space-resolved measurement of the thickness field

    Science.gov (United States)

    Ligoure, Christian; Vernay, Clara; Ramos, Laurence

    2014-11-01

    The collision of a liquid drop against a small target results in the formation of a thin liquid sheet that extends radially until it reaches a maximum diameter. We have developed an original time- and space-resolved technique to measure the thickness field of this class of liquid sheet, based on the grey level measurement of the image of a dyed liquid sheet recorded using a fast camera. This method enables a precise measurement of the thickness in the range (10--450) μm, with a temporal resolution equals to that of the camera. Two asymptotic regimes for the expansion of the sheet are evidenced. The scalings of the thickness with t and r measured in the two regimes are those that were predicted but never experimentally measured before. Interestingly, our experimental data also evidence the existence of a maximum of the film thickness hmax (r) at a radial position rhmax (t) corresponding to the crossover of these two asymptotic regimes. The maximum moves with a constant velocity of the order of the impact velocity, Hence, our data has allowed one to reconcile the two apparently inconsistent theoretical predictions found in the literature Thanks to our visualization technique, we also evidence an azimuthal thickness modulation. Financial support from Solvay is acknowledged.

  18. Measurement of sediments thickness by ground penetrating radar; Denjihaho wo mochiita kotei taisekibutsu soatsu no sokutei

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, E. [Tokyo Electric Power Co. Inc., Tokyo (Japan); Inagaki, M.

    1997-05-27

    An attempt was made to measure thickness of a layer of reservoir bottom sediments by utilizing the electromagnetic reflection method. Because water is a substance difficult for electromagnetic waves to permeate, considerations were given on to suppress attenuation to a minimum, and improve receiving sensitivity. The test used monocycle pulses with a central frequency of 200 MHz. In order to generate stabilized pulses with little unnecessary reflection, an antenna as large as it can be fitted into a rubber boat was employed. In order to acquire referential data, the test was carried out by using simultaneously a sound wave exploration device. The lake at which the test was carried out is a regulating reservoir with a size of about 250 m {times} 150 m, with its bottom made of concrete slab. This means that the lake consists of a three-layer structure comprising water, soil deposits, and concrete bottom from the water surface. According to an example of acquired electromagnetic exploration records, boundary reflection of water and sediments was observed clearly at water depths of 2 to 3 m as a shallow portion and 5 to 6 m as a deep portion. Reflection between the sediments and the bottom plate was also observed sufficiently distinctly. 3 refs., 8 figs.

  19. Validation of UV-visible aerosol optical thickness retrieved from spectroradiometer measurements

    Directory of Open Access Journals (Sweden)

    C. Brogniez

    2008-08-01

    Full Text Available Global and diffuse UV-visible solar irradiances are routinely measured since 2003 with a spectroradiometer operated by the Laboratoire d'Optique Atmosphérique (LOA located in Villeneuve d'Ascq, France. The analysis of the direct irradiance derived by cloudless conditions enables retrieving the aerosol optical thickness (AOT spectrum in the 330–450 nm range. The site hosts also sunphotometers from the AERONET/PHOTONS network performing routinely measurements of the AOT at several wavelengths. On one hand, comparisons between the spectroradiometer and the sunphotometer AOT at 440 nm as well as, when available, at 340 and 380 nm, show good agreement: in 2003–2005 at 440 nm the correlation coefficient, the slope and the intercept of the regression line are [0.97, 0.95, 0.025], and in 2006 at 440, 380 and 340 nm they are [0.97, 1.00, −0.013], [0.97, 0.98, −0.007], and [0.98, 0.98, −0.002] respectively. On the other hand, the AOT's spectral variations have been compared using the Angström exponents derived from AOT data at 340 and 440 nm for both instruments. The comparisons show that this parameter is difficult to retrieve accurately due to the small wavelength range and due to the weak AOT values. Thus, AOT derived at wavelengths outside the spectroradiometer range by means of an extrapolation using the Angström parameter would have large uncertainties, whereas spectroradiometer's spectral AOT could be used for direct validation of other AOT, such as those provided by satellite instruments.

  20. Effects of the 1998 Drought on the Freshwater Lens in the Laura Area, Majuro Atoll, Republic of the Marshall Islands

    Science.gov (United States)

    Presley, Todd K.

    2005-01-01

    Lower than average rainfall during late 1997 and early 1998 in Majuro Atoll, Republic of the Marshall Islands, caused a drought and severe drinking-water shortage. Majuro depends on a public rainfall catchment system, which uses an airport runway and storage reservoirs. The storage reservoirs can supply water for about 30 to 50 days without replenishment. In February 1998, after a few months with less than one inch of rainfall per month, a drought-related disaster was declared. Reverse-osmosis water-purification systems were brought to Majuro to help alleviate the water shortage. Concurrent with the water-purification program, ground water from a freshwater lens in the Laura area of the atoll was pumped at increased rates. Of the total consumed water during this period, ground water from Laura supplied between 90 percent (March 1998) and 64 percent (May 1998) of the drinking water. Due to public concern, a study was initiated to determine the effects of the drought on the freshwater lens. The areal extent of the freshwater lens is about 350 acres. A monitoring-well network, consisting of multiple wells driven to varying depths at 11 sites, was installed to determine the thickness of the freshwater lens. Similar locations relative to an earlier study were chosen so that the data from this study could be compared to 1984-85 data. At the end of the drought in June 1998, the freshwater near the middle of the lens was about 45 feet thick; and at the north and south ends, the freshwater was about 25 to 38 feet thick, respectively. Monitoring of the freshwater lens was continued through the wet season following the drought. The lens increased in thickness by 1 to 8 feet after 7 months of rainfall. Greater increases in lens thickness were measured on the lagoon side than on the ocean side of the freshwater lens. Lens thickness during August 1998, and seasonal variation of lens thickness in 1998, were compared to data collected in 1984-85. Comparison of lens thickness from

  1. Proposal for dose measurement in the crystalline lens and thyroid in computerized tomography of paranasal sinuses

    International Nuclear Information System (INIS)

    Mello, Ana Caroline; Machado Neto, Vicente

    2014-01-01

    With the evolution of diagnostic imaging equipment, a computerized tomography (CT) has become one of the most used tests to assess pathologies affecting the paranasal sinuses. This work aims at presenting a method of obtaining measurements of dose in the eye lenses and thyroid, from the execution of CT of the paranasal sinuses protocol. Experimental procedure will be used in an object simulator (phantom) head and neck made with accessible materials and thermoluminescent dosimeters (TLDs) of LiF: Mg,Ti for the absorbed dose in the regions of interest, when exposed to radiation in a CT scanner 16 channels. After the dosimetric evaluation with phantom use, this methodology will be applied in vivo, or in patients with medical request for the examination and approval by the Ethics Committee. Thus, at the end of this survey protocols and actions aimed at reducing the absorbed dose in the eye lenses and thyroid without impairing the diagnostic image quality can be proposed. (author)

  2. Relationship between two-dimensional ultrasound measurement of placental thickness and estimated fetal weight

    Directory of Open Access Journals (Sweden)

    Ademola A Adeyekun

    2015-01-01

    Full Text Available Background/Aim: The placenta plays a major role in fetal well-being, and fetal weight is very important to neonatal survival. There probably exists a relationship between placental dimension and fetal size. Data on ultrasound assessed placenta thickness and fetal weight are scanty in the Nigerian literature. This study aimed to establish a relationship between ultrasound estimated placental thickness and fetal weight. Materials and Methods: Four hundred and twenty apparently healthy pregnant women at gestational age 15-40 weeks were sonographically examined, with a 3.5 MHz curvilinear transducer of a Sonoace X6 machine (Medison Co., Korea. Placenta thickness, in millimeters, and fetal weight, in grams, was estimated for each subject. Correlation between the two parameters was assessed. P ≤ 0.05 were considered to be significant. Results: Mean placental thickness (PT ranged from 22.6 ± 2.5 mm at 15 weeks to 40.9 ± 7.2 mm at 30 weeks, while estimated fetal weight (EFW ranged from 147.0 ± 16.5 g at 15 weeks to 3.304.8 ± 284.6 g at 40 weeks. The mean values of placenta thickness and EFW throughout gestation were 35.5 ± 7.0 mm and 1555.0 ± 1004 g, respectively. There was significant correlation between placenta thickness and EFW r = 0.668; P = 0.000. Conclusion: The study established a fairly linear relationship between placental thickness and EFW. A normogram of ultrasound estimated placenta thickness and fetal weight is derived.

  3. Acceptance testing of the eddy current probes for measurement of aluminum hydroxide coating thickness on K West Basin fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Pitner, A.L.

    1998-08-21

    During a recent visual inspection campaign of fuel elements stored in the K West Basin, it was noted that fuel elements contained in sealed aluminum canisters had a heavy translucent type coating on their surfaces (Pitner 1997a). Subsequent sampling of this coating in a hot cell (Pitner 1997b) and analysis of the material identified it as aluminum hydroxide. Because of the relatively high water content of this material, safety related concerns are raised with respect to long term storage of this fuel in Multi-Canister Overpacks (MCOs). A campaign in the basin is planned to demonstrate whether this coating can be removed by mechanical brushing (Bridges 1998). Part of this campaign involves before-and-after measurements of the coating thickness to determine the effectiveness of coating removal by the brushing machine. Measurements of the as-deposited coating thickness on multiple fuel elements are also expected to provide total coating inventory information needed for MCO safety evaluations. The measurement technique must be capable of measuring coating thicknesses on the order of several mils, with a measurement accuracy of 0.5 mil. Several different methods for quantitatively measuring these thin coatings were considered in selecting the most promising approach. Ultrasonic measurement was investigated, but it was determined that due to the thin coating depth and the high water content of the material, the signal would likely pass directly through to the cladding without ever sensing the coating surface. X-ray fluorescence was also identified as a candidate technique, but would not work because the high gamma background from the irradiated fuel would swamp out the low energy aluminum signal. Laser interferometry could possibly be applied, but considerable development would be required and it was considered to be high risk on a short term basis. The consensus reached was that standard eddy current techniques for coating thickness measurement had the best chance for

  4. Structural health monitoring ultrasonic thickness measurement accuracy and reliability of various time-of-flight calculation methods

    Science.gov (United States)

    Eason, Thomas J.; Bond, Leonard J.; Lozev, Mark G.

    2016-02-01

    The accuracy, precision, and reliability of ultrasonic thickness structural health monitoring systems are discussed in-cluding the influence of systematic and environmental factors. To quantify some of these factors, a compression wave ultrasonic thickness structural health monitoring experiment is conducted on a flat calibration block at ambient temperature with forty four thin-film sol-gel transducers and various time-of-flight thickness calculation methods. As an initial calibration, the voltage response signals from each sensor are used to determine the common material velocity as well as the signal offset unique to each calculation method. Next, the measurement precision of the thickness error of each method is determined with a proposed weighted censored relative maximum likelihood analysis technique incorporating the propagation of asymmetric measurement uncertainty. The results are presented as upper and lower confidence limits analogous to the a90/95 terminology used in industry recognized Probability-of-Detection assessments. Future work is proposed to apply the statistical analysis technique to quantify measurement precision of various thickness calculation methods under different environmental conditions such as high temperature, rough back-wall surface, and system degradation with an intended application to monitor naphthenic acid corrosion in oil refineries.

  5. Clinical Factors Associated with Lamina Cribrosa Thickness in Patients with Glaucoma, as Measured with Swept Source Optical Coherence Tomography.

    Directory of Open Access Journals (Sweden)

    Kazuko Omodaka

    Full Text Available To investigate the influence of various risk factors on thinning of the lamina cribrosa (LC, as measured with swept-source optical coherence tomography (SS-OCT; Topcon.This retrospective study comprised 150 eyes of 150 patients: 22 normal subjects, 28 preperimetric glaucoma (PPG patients, and 100 open-angle glaucoma patients. Average LC thickness was determined in a 3 x 3 mm cube scan of the optic disc, over which a 4 x 4 grid of 16 points was superimposed (interpoint distance: 175 μm, centered on the circular Bruch's membrane opening. The borders of the LC were defined as the visible limits of the LC pores. The correlation of LC thickness with Humphrey field analyzer-measured mean deviation (MD; SITA standard 24-2, circumpapillary retinal nerve fiber layer thickness (cpRNFLT, the vertical cup-to-disc (C/D ratio, and tissue mean blur rate (MBR was determined with Spearman's rank correlation coefficient. The relationship of LC thickness with age, axial length, intraocular pressure (IOP, MD, the vertical C/D ratio, central corneal thickness (CCT, and tissue MBR was determined with multiple regression analysis. Average LC thickness and the correlation between LC thickness and MD were compared in patients with the glaucomatous enlargement (GE optic disc type and those with non-GE disc types, as classified with Nicolela's method.We found that average LC thickness in the 16 grid points was significantly associated with overall LC thickness (r = 0.77, P < 0.001. The measurement time for this area was 12.4 ± 2.4 minutes. Average LC thickness in this area had a correlation coefficient of 0.57 with cpRNFLT (P < 0.001 and 0.46 (P < 0.001 with MD. Average LC thickness differed significantly between the groups (normal: 268 ± 23 μm, PPG: 248 ± 13 μm, OAG: 233 ± 20 μm. Multiple regression analysis showed that MD (β = 0.29, P = 0.013, vertical C/D ratio (β = -0.25, P = 0.020 and tissue MBR (β = 0.20, P = 0.034 were independent variables significantly

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-15

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

  7. Reliability of power profiles measured on NIMO TR1504 (Lambda-X) and effects of lens decentration for single vision, bifocal and multifocal contact lenses.

    Science.gov (United States)

    Kim, Eon; Bakaraju, Ravi C; Ehrmann, Klaus

    2016-01-01

    To evaluate the repeatability of power profiles measured on NIMO TR1504 (Lambda-X, Belgium) and investigate the effects of lens decentration on the power profiles for single vision (SV), bifocal (BF) and multifocal (MF) contact lenses. Accuracy of the sphere power was evaluated using single vision BK-7 calibration glass lenses of six minus and six plus powers. Three SV and four BF/MF contact lenses - three lenses each, were measured five times to calculate the coefficients of repeatability (COR) of the instrument. The COR was computed for each chord position, lens design, prescription power and operator. One lens from each type was measured with a deliberate decentration up to ±0.5mm in 0.1mm steps. For all lenses, the COR varied across different regions of the half-chord position. In general, SV lenses showed lower COR compared to the BF/MF group lenses. There were no noticeable trends of COR between prescription powers for SV and BF/MF lenses. The shape of the power profiles was not affected when lenses were deliberately decentered for all SV and PureVision MF lenses. However, for Acuvue BF lenses, the peak to trough amplitude of the power profiles flattened up to 1.00D. The COR across the half-chord of the optic zone diameter was mostly within clinical relevance except for the central 0.5mm half-chord position. COR were dependent on the lens type, whereby BF/MF group produced higher COR than SV lenses. The effects of deliberate decentration on the shape of power profiles were pronounced for lenses where the profiles had sharp transitions of power. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  8. Suprailiac or abdominal skinfold thickness measured with a skinfold caliper as a predictor of body density in Japanese adults.

    Science.gov (United States)

    Demura, Shin-ichi; Sato, Susumu

    2007-09-01

    Measurement of subcutaneous fat thickness with a skinfold caliper is a simple and inexpensive technique for assessment of body composition, but is influenced by the skin site or the obesity level. The resulting measurement errors may influence the prediction accuracy of body density. We therefore aimed to clarify the characteristics of measurement errors with a skinfold caliper and to determine useful measurement sites for the prediction of body density in Japanese adults of wide-ranging age and obesity levels. The present study included 126 Japanese male and 77 female subjects ranging from 21 to 81 years old. They were divided into a "non-obese group" and an "obese group", based on the Japanese criteria of obesity (BMI > or = 25 kg/m(2)). Subcutaneous fat thickness was measured at 14 sites with a skinfold caliper and ultrasound. Percent body fat was measured by dual-energy x-ray absorptiometry, and body density was calculated using Brozek's formula. Sex and obesity level differences in the measurement error of skinfolds (ultrasound minus skinfold caliper measurements) were examined by 2 x 2 ANOVA (sex and obesity groups) for each site. The relationship between body density and the systematic error was examined. We developed an accurate prediction equation for body density with smaller measurement and systematic errors. Although measurement errors in skinfold thickness tended to increase with increasing obesity levels, the influence was smaller for the abdominal and suprailiac skinfolds compared with other sites. Measurement of suprailiac or abdominal skinfold thickness is useful to accurately estimate body density in Japanese adults.

  9. UWB, Non Dispersive Radiation From the Planarly Fed Leaky Lens Antenna—Part II: Demonstrators and Measurements

    NARCIS (Netherlands)

    Neto, A.; Monni, S.; Nennie, F.A.

    2010-01-01

    We provide for the first time the experimental characterization of a planarly fed ultrawideband leaky lens antenna. The paper includes the description and the experimental characterization of two antenna prototypes with radiating element realized in printed circuit board technology. The impedance

  10. Experimental measurements of a prototype high-concentration Fresnel lens and sun-tracking method for photovoltaic panel's efficiency enhancement

    Science.gov (United States)

    Rajaee, Meraj; Ghorashi, Seyed Mohamad Bagher

    2015-08-01

    Concentrator photovoltaic modules are a promising technology for highly efficient solar energy conversion. This system presents several advantages due to additional degrees of freedom that has been provided by the spectral separation such as cost and mass reduction, increase in the incident solar flux on PV cells and performances. This paper has proposed a unique photovoltaic solar cell system that consists of semi-Fresnel lens convergent structure and a novel two axis sun tracking module to enhance the efficiency of solar cell by using less cell area and energy losses. The grooves of this lens are calculated according to the refraction and convergent angles of the light easy for perpendicular incidence angle. The update time interval during tracking causes misalignment of the lens' optical axis versus the sunrays. Then an inventive sun-tracking method is introduced to adjust the module so that the incident rays are always perpendicular to the module's surface. As a result, all rays will be refracted with the predetermined angles. This way the focus area is reduced and smaller cells can be used. We also mentioned different module connections in order to provide compensation method during losses, for networks and power systems. Experimental results show that using semi-Fresnel lens, along with the sun-tracking method increases the efficiency of PV panel.

  11. Decreased optical coherence tomography-measured pericentral retinal thickness in patients with diabetes mellitus type 1 with minimal diabetic retinopathy

    NARCIS (Netherlands)

    Biallosterski, Carine; van Velthoven, Mirjam E. J.; Michels, Robert P. J.; Schlingemann, Reinier O.; DeVries, J. Hans; Verbraak, Frank D.

    2007-01-01

    AIM: A comparison of retinal thickness (RT) measurements with optical coherence tomography (OCT) in patients with type 1 diabetes mellitus (DM) and no or minimal diabetic retinopathy (DR) versus healthy controls. METHODS: Fifty-three patients with type 1 DM with no or minimal DR underwent full

  12. Limits to the resolution of beam size measurement from fluorescent screens due to the thickness of the phosphor

    International Nuclear Information System (INIS)

    Johnson, C.D.

    1988-01-01

    This paper discusses the use of fluorescent screens for the measurement of beam profiles on non-circulating particle beams. An expression for the intensity of the beam profile as a function of phosphor thickness is given. 3 refs., 8 figs

  13. Influence of zirconia framework thickness on residual stress profile in veneering ceramic: measurement by hole-drilling.

    Science.gov (United States)

    Mainjot, Amélie K; Schajer, Gary S; Vanheusden, Alain J; Sadoun, Michaël J

    2012-04-01

    Framework design is reported to influence chipping in zirconia-based restorations, which is an important cause of failure of such restorations. Residual stress profile in the veneering ceramic after the manufacturing process is an important predictive factor of the mechanical behavior of the material. The objective of this study is to investigate the influence of framework thickness on the stress profile measured in zirconia-based structures. The stress profile was measured with the hole-drilling method in bilayered disc samples of 20mm diameter with a 1.5 mm thick veneering ceramic layer. Six different framework thicknesses from 0.5 mm to 3 mm were studied. Two different cooling procedures were also investigated. Compressive stresses were observed in the surface, and tensile stresses in the depth of most of the samples. The slow cooling procedure was found to promote the development of interior tensile stresses, except for the sample with a 3mm thick framework. With the tempering procedure, samples with a 1.5 mm thick framework exhibited the most favorable stress profile, while thicker and thinner frameworks exhibited respectively in surface or interior tensile stresses. The measurements performed highlight the importance of framework thickness, which determine the nature of stresses and can explain clinical failures encountered, especially with thin frameworks. The adequate ratio between veneering ceramic and zirconia is hard to define, restricting the range of indications of zirconia-based restorations until a better understanding of such a delicate veneering process is achieved. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Examination of the X-ray piping diagnostic system using EGS4 (measuring the thickness of a steel pipe with rust)

    International Nuclear Information System (INIS)

    Kajiwara, G.

    2001-01-01

    In a series of papers entitled 'Examination of the X-ray piping diagnostic system using EGS4' presented the proceedings of the EGS4 users' meetings, I discussed the possibility of measuring the thickness of piping walls with rust. In the present paper, I describe, based on our earlier results, how the thickness of steel pipes with rust can be measured. I conducted EGS4 simulation to measure the thickness of a combination of steel and rust and made an energy absorption diagram for this combination. The equivalent thickness of steel was obtained through experiments and the system operation. The thickness of the steel determined by using the diagram agreed well with the actual steel thickness obtained by the experiments. In the future, we will focus on how to automate this measurement procedure and how to use the same procedure to measure the thickness of pipes filled with water. (author)

  15. Comparison of corneal thickness measurements using ultrasound pachymetry, ultrasound biomicroscopy, and digital caliper in frozen canine corneas.

    Science.gov (United States)

    Jeong, Seowoo; Kang, Seonmi; Park, Sangwan; Park, Eunjin; Lim, Jaegook; Nam, Taekjin; Seo, Kangmoon

    2017-11-07

    To evaluate the clinical efficacy among ultrasound pachymetry (UP), ultrasound biomicroscopy (UBM), and manual measurement (MM) with digital caliper by comparing corneal thickness (COT) values obtained from frozen canine corneas ex vivo. COT was measured using UP, UBM, and MM in eight enucleated normal canine eyes frozen at -20 °C for 4 weeks. After thawing at room temperature for 2 h, the COT values were obtained from five sites on each cornea: central corneal thickness (CCOT), thickness at the 3, 6, 9, and 12 o'clock positions (3COT, 6COT, 9COT, and 12COT, respectively). For each device, measurements were performed three times at each designated site by one operator. Intraclass correlation coefficient, repeated-measures analysis of variance, and Bland-Altman plot were performed for statistical analyses. The mean CCOT was 839.0 ± 138.2, 857.6 ± 127.9, and 849.1 ± 132.8 μm for UP, UBM, and MM, respectively. There was no statistically significant difference among the measurements by all three devices (P > 0.05). The statistical agreement among these devices was also shown to be good according to Bland-Altman plots. In addition, the values measured on the peripheral sites of the cornea (3COT, 6COT, 9COT, and 12COT) also revealed no significant differences among the three devices. The difference between CCOT and peripheral corneal thickness was also statistically insignificant. The UP, UBM, and MM measurements showed statistically similar COT values. The UBM and UP provided accurate and reliable measurements comparable to MM and could be used effectively for clinical COT measurements. © 2017 American College of Veterinary Ophthalmologists.

  16. Left ventricular wall thickness in hypertrophic cardiomyopathy. Comparisons of measurements by magnetic resonance imaging, cineangiography, and echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Tetsuya; Nagano, Yutaka; Hashimoto, Satoshi; Kawai, Chuichi; Sakurai, Tsunetaro; Osakada, Genta (Kyoto Univ. (Japan). Faculty of Medicine)

    1988-12-01

    To evaluate the usefulness of magnetic resonance imaging (MRI) in measuring regional wall thickness of the left ventricle, 11 patients with hypertrophic cardiomyopathy (HCM) were imaged. The measurements were compared with those obtained by two-dimensional echocardiography (2D-echo) and cineangiography. Regional wall thickness was ascertained at six locations including the base, middle, and apex of the interventricular septum (IVS) and left ventricular posterior wall (LVPW) from the two selected transverse sections. All of these six locations were also measured for the IVS by biventriculography and for the LVPW by left ventriculography with the left anterior oblique view. Only the base was measured for both the IVS and LVPW using 2D-echo because of the difficulty in obtaining good images for the middle and apex of the left ventricle. The measurements by MRI correlated well with those obtained by 2D-echo and cineangiography in the majority of locations. At the base, where the wall thickness was measured by the three methods, the measurements of the IVS correlated well each other (r=0.63 to 0.81). However, a good correlation was obtained only between 2D-echo and MRI for the LVPW (r=0.75). The correlation between MRI and cineangiography was generally good for the IVS at any levels (r=0.76 to 0.87), but not for the LVPW. This was partially due to the narrow range of data for the LVPW as well as the difficulty in determining the epicardial border in left ventriculograms. In conclusion, regional wall thickness can be correctly measured by MRI in any location of the left ventricle even at the apex, where measurement is difficult by other methods. (author).

  17. Reference intervals for common carotid intima-media thickness measured with echotracking: relation with risk factors

    NARCIS (Netherlands)

    Engelen, L.; Ferreira, I.; Stehouwer, C.D.A.; Franco, O.H.; Grobbee, D.E.; Schouw, van der Y.T.; Twisk, J.W.R.; Dekker, J.J.A.; Feskens, E.J.M.

    2013-01-01

    Common carotid artery intima-media thickness (CCIMT) is widely used as a surrogate marker of atherosclerosis, given its predictive association with cardiovascular disease (CVD). The interpretation of CCIMT values has been hampered by the absence of reference values, however. We therefore aimed to

  18. Triceps skin fold thickness as a measure of body fat in Nigerian ...

    African Journals Online (AJOL)

    owner

    2012-11-26

    Nov 26, 2012 ... as obese. Conclusion: Triceps SFT remain a fair surrogate for the assessment of adiposity, the component of over- weight that leads to pathology. Key words: Skin fold thickness, bioelectrical impedance analysis, body fat, obesity, adolescents. Introduction. Nutrition transition is increasingly evident in middle.

  19. Articular Cartilage Thickness Measured with US is Not as Easy as It Appears

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Bartels, E. M.; Wilhjelm, Jens E.

    2011-01-01

    Background: Theoretically, the high spatial resolution of US makes it well suited to monitor the decrease in articular cartilage thickness in osteoarthritis. A requirement is, however, that the borders of the cartilage are correctly identified and that the cartilage ismeasured under orthogonal...

  20. Thickness measurement of Sn-Ag hot dip coatings on Large Hadron Collider Superconducting strands by coulometry

    CERN Document Server

    Arnau-Izquierdo, G; Oberli, L R; Scheuerlein, C; Taborelli, M; 10.1149/1.1715094

    2004-01-01

    Amperostatic coulometry is applied for the thickness measurement of Sn-Ag hot dip coatings, which comprise an extended Sn-Cu interdiffusion layer. Complementary measurements, notably weight loss, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF) and dynamic secondary ion mass spectroscopy (DSIMS) have been performed in order to obtain a better interpretation of the coulometry results. Based on the experimental results presented in this article the three potential changes that are observed during coulometry measurements are ascribed to (1) the entire dissolution of pure Sn, (2) the formation of a CuCl salt layer and (3) the surface passivation. The measurement of the pure Sn mass is well reproducible despite of strong coating thickness variations that are detected by XRF. Several experimental problems, in particular a coating undercutting, hamper the determination of the Sn mass in the intermetallic Sn-Cu layer.

  1. The influence of steel roughness and granulation on the accuracy of part thickness measurement by means of ultrasounds

    Science.gov (United States)

    Sontea, S.; Baltanoiu, M.

    1974-01-01

    Nondestructive measurement of the thickness of one-sided parts can be successfully conducted with the aid of ultrasounds. Using an ultrasonic defectoscope equipped with a highly precise device for thickness measurement, the experimental results obtained and the parameters that influence them are discussed. It is known that the manner of attaching the probe to the surface to be tested is influenced by the roughness of the surface. Likewise, in view of the fact that measurement results are influenced by the velocity of ultrasounds in the material to be investigated, they are also conditioned by the size of the structure. These factors and the manner in which they influence measurement results are also described.

  2. Thermal Lens Microscope

    Science.gov (United States)

    Uchiyama, Kenji; Hibara, Akihide; Kimura, Hiroko; Sawada, Tsuguo; Kitamori, Takehiko

    2000-09-01

    We developed a novel laser microscope based on the thermal lens effect induced by a coaxial beam comprised of excitation and probe beams. The signal generation mechanism was confirmed to be an authentic thermal lens effect from the measurement of signal and phase dependences on optical configurations between the sample and the probe beam focus, and therefore, the thermal lens effect theory could be applied. Two-point spatial resolution was determined by the spot size of the excitation beam, not by the thermal diffusion length. Sensitivity was quite high, and the detection ability, evaluated using a submicron microparticle containing dye molecules, was 0.8 zmol/μm2, hence a distribution image of trace chemical species could be obtained quantitatively. In addition, analytes are not restricted to fluorescent species, therefore, the thermal lens microscope is a promising analytical microscope. A two-dimensional image of a histamine molecule distribution, which was produced in mast cells at the femtomole level in a human nasal mucous polyp, was obtained.

  3. Ultrasound Intima-Media Thickness and Diameter Measurements of the Common Carotid Artery in Patients with Renal Failure Disease

    OpenAIRE

    Loizou , Christos ,; Anastasiou , Eleni; Kasparis , Takis; Lazarou , Theodoros; Pantziaris , Marios; Pattichis , Constandinos ,

    2013-01-01

    Part 8: Third Workshop on Artificial Intelligence Applications in Biomedicine (AIAB 2013); International audience; Although the intima-media thickness (IMT) of the common carotid artery (CCA) is an established indicator of cardiovascular disease (CVD), its relationship with renal failure disease (RFD) is not yet established. In this study, we use an automated integrated segmentation system based on snakes, for segmenting the CCA, perform measurements of the IMT, and measure the CCA diameter (...

  4. Measurement of liquid film thickness in air - water two phase flows in conventional and mini channels using image processing

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, Arunkumar; Mahadevan, Swetha; Muniyandi, Venkatesan [SASTRA University, Thanjavur (India)

    2015-05-15

    The measurement and study of liquid films in the case of two phase flows is significant in many heat transfer and mass transfer applications, such as chemical process industries, micro reactors, coating processes and in boilers. The focus of the present study was to measure and characterize the thickness of the liquid films for various two phase flow regimes in conventional and in mini channels using a non-intrusive technique. Experiments were performed on tubes of diameters 0.6, 1.5, 2.6 and 3.4mm. The superficial velocities of gas and liquid are in the range of 0.01-50 and 0.01-3m/s, respectively. The flow patterns were recorded with a high speed camera. A method to determine the two phase flow velocity using image registration has been discussed. Morphological processing and gray scale analysis were used to determine the liquid film thickness and characterize the flow regimes. The flow patterns identified are bubbly, dispersed bubbly, slug, slug-annular, wavy-annular, stratified, and annular. The flow regimes were validated with flow maps available in the literature. The liquid film thickness was identified by distance transform technique in image processing. The magnitude of film thickness varied with liquid and gas flow velocities. The film thickness was represented in terms of capillary number. The variation in film thickness along the length of the flow regime has been discussed. A relation between the liquid film thicknesses measured using the non-intrusive image processing technique and capillary number for the conventional and mini tubes is proposed based on the analysis. h/d=2.03Ca{sup 0.13}We{sup 0.52} for Bo>1 h/d=1.08Ca{sup 0.4}We{sup 0.35} for Bo<1 It is concluded from the proposed correlation that the variation in liquid film thickness is different for conventional and mini channels because of the effect of inertial dominance in conventional channels and viscous dominance in mini channels.

  5. Non-contact Measurement of Remaining Thickness of Corroding Superheater Tubes. Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Borggreen, Kjeld; Storesund, Jan

    2007-12-15

    The Electro Magnetic Acoustic Transducer (EMAT) is a contactless thickness gauge for detection of corrosion on superheater tubes; it candidates as substitute for conventional manually operated contact UT transducers. It is the aim of the project to demonstrate the usefulness of two simple EMAT systems, Panametrics and Sonatest, for fast and reliable tube thickness inspections in difficult-to-access superheater sections. The present Phase 2 of the project involves testing of the systems on real compact superheaters in remote operation with the help of a mechanical manipulator designed and built for the purpose. The results are the following: - Both EMAT systems work well when tested in the field during handheld operation on tubes with a moderate thick layer of corrosion products and ash. The practical obtainable speed of cross-panel inspection of easily accessible panels is approximately 6 tubes per minute (6 thickness readings per minute). - The Sonatest system works well when tested in the field during remote operation on heavily corroded superheater tubes with thick ash layer. The Panametrics system was not found suitable for this type of field work. - The mechanical manipulator works well for cross-panel inspection of difficult-to-access superheater sections independent of the tube dimensions and the free space between the panels. In its present design it needs few improvements. - The practical obtainable speed of cross-panel inspection is 3 tubes per minute (3 thickness readings per minute). This speed is limited by the detection rate of the EMAT system and not by the travelling speed of the probe. - Scanning of tubes along their axis was never attempted, because the EMAT instruments were not capable of collecting data coming as a continuous stream. - It cannot be judged from visual alone and hardly from the service data, if a tube or a panel can be inspected by the magnetostrictive EMAT method or not. - The main contribution to failure of the EMAT inspection

  6. The effect of endometrial thickness and pattern measured by ultrasonography on pregnancy outcomes during IVF-ET cycles

    Directory of Open Access Journals (Sweden)

    Zhao Jing

    2012-11-01

    Full Text Available Abstract Background To study the effect of endometrial thickness and pattern measured using ultrasound upon pregnancy outcomes in patients undergoing IVF-ET. Method One thousand nine hundred thirty-three women undergoing IVF treatment participated in the study. We assessed and recorded endometrial patterns and thickness on the day of human chorionic gonadotropin (hCG administration. Receiver operator curves (ROC were used to determine the predictive accuracy of endometrial thickness. Cycles were divided into 3 groups depending on the thickness (group 1: ≤ 7 mm; group 2: > 7 mm to ≤ 14 mm; group 3: > 14 mm. Each group was subdivided into three groups according to the endometrial pattern as follows: pattern A (a triple-line pattern consisting of a central hyperechoic line surround by two hypoechoic layers; pattern B (an intermediate isoechogenic pattern with the same reflectivity as the surrounding myometrium and a poorly defined central echogenic line; and pattern C (homogenous, hyperechogenic endometrium. Clinical outcomes such as implantation and clinical pregnancy rates were analyzed. Results The endometrial thickness predicts pregnancy outcome with high sensitivity and specificity. The cutoff value was 9 mm. The implantation rate and clinical pregnancy rate in group 3 were 39.1% and 63.5%, respectively, which were significantly higher than those in group 2 (33.8% and 52.1%, respectively and group 1 (13% and 25.5%, respectively. Among those with Pattern A, the implantation rate and clinical pregnancy rate were 35.3% and 55.2%, respectively, which were significantly higher than among women with Pattern B (32.1% and 50.9%, respectively and Pattern C (23.4% and 37.4%, respectively. In groups 1 and 3, clinical pregnancy and implantation rates did not show any significant differences between different endometrial patterns (P > 0.05, whereas in group 2, the clinical pregnancy rate and implantation rate in women with pattern A were

  7. Effective X-ray beam size measurements of an X-ray tube and polycapillary X-ray lens system using a scanning X-ray fluorescence method

    Energy Technology Data Exchange (ETDEWEB)

    Gherase, Mihai R., E-mail: mgherase@csufresno.edu; Vargas, Andres Felipe

    2017-03-15

    Size measurements of an X-ray beam produced by an integrated polycapillary X-ray lens (PXL) and X-ray tube system were performed by means of a scanning X-ray fluorescence (SXRF) method using three different metallic wires. The beam size was obtained by fitting the SXRF data with the analytical convolution between a Gaussian and a constant functions. For each chemical element in the wire an effective energy was calculated based on the incident X-ray spectrum and its photoelectric cross section. The proposed method can be used to measure the effective X-ray beam size in XRF microscopy studies.

  8. Thickness measurement of aluminum, titanium, titanium silicide, and tungsten silicide films by x-ray fluorescence

    International Nuclear Information System (INIS)

    Ernst, S.; Lee, C.O.; Lee, J.J.

    1988-01-01

    X-ray fluorescence (XRF) has received a great deal of attention in the last few years as a quantitative means of determining both the stoichiometry and thickness of many different kinds of films. Examples include Ag and Cu films on mica substrates, Sn-Pb alloys on steel substrates, Al-Ti multilayers on Cu substrates and oxide films on silicon substrates. In XRF the sample is irradiated with x-rays which in turn cause x-rays to be given off by the sample. These x-rays that are given off by the sample can then be analyzed both for energy and intensity. The energy of the x-rays is characteristic of the elemental makeup of the sample and the intensity of the x-rays is dependent on how much of the particular element is present. The intensity then can be related to the thickness of a film if the stoichiometry of the film can be assumed constant. With the increased interest in silicides and more recently, the self-aligned silicide (salicide) process (8-10) for VLSI applications, in-line process monitoring of silicide film thickness has become important to integrated circuit manufacturing. In this study, the number of x-ray photons given of by Al, Ti, titanium silicide, and tungsten silicide films on silicon-based substrates was quantified so that a film thickness for an unknown sample could then be determined easily. In addition, XRF is a more accurate technique, limited principally by the accuracy technique, limited principally by the accuracy of the reference used and the amount of time the x-ray photons are counted

  9. Application of the HHT Method to the Non-contact Thickness Measurement of an Axially Moving Thin Plate

    Science.gov (United States)

    Wu, Yangfang; Lu, Qianqian; Xia, Chunlin; Ding, Fan

    2017-08-01

    Non-contact thickness measuring systems can be found in a wide spectrum of technologies. In this paper, Hilbert-Huang transform method is used to analyze the real time signals of a measuring system which includes two round conveyor strings carrying a thin plate, a solar wafer as a sample under test. The vibrations of moving strings and the plate, which are sensitive to moving speed and initial tension in the string, are introduced briefly; the relevant analyses should be helpful for the system design. Using EMD-based time-domain filtering and complementary method, thickness variations and error bands are estimated for different cases. The results show that HHT method as an adaptive time-frequency method, should be potential in measurement engineering applications.

  10. On method of muon spectrum measurements by the scintillation detectors of a large thickness T4t sub o

    Science.gov (United States)

    Ryazhskaya, O. G.

    1985-01-01

    Various methods for the study of muon spectrum are presented. The direct ones include the muon energy measurements by magnetic spectrometers. The indirect ones deal with the reconstruction of the muon spectrum from the spectrum of secondary particles obtained by burst or calorimeter technique. The burst technique is based on the measurement of the number of cascade particles, mainly in the cascade maximum, by the detectors of small thickness T sub 0. The calorimeter method consist in determination of the cascade energy with help of the cascade curve shape. The multilayer detectors are used for this purpose. They are usually comprised of proportional counters, X-ray emulsion chambers or scintillation counters with the target material placed between them. The scintillation detectors of a large thickness measures the total cascade energy directly and the detector works as a true calorimeter. When the total energy is detected, the cascade spectrum differs from the muon one.

  11. In vivo thickness measurement of basal cell carcinoma and actinic keratosis with optical coherence tomography and 20-MHz ultrasound

    DEFF Research Database (Denmark)

    Mogensen, Mette; Nürnberg, B.M.; Forman, J.L.

    2009-01-01

    was measured with a colorimeter. Results OCT presented narrower limits of agreement than HFUS. Both methods overestimated thickness but OCT was significantly less biased (0Æ392 mm vs. 0Æ713 mm). No relation between OCT penetration depth and skin colour was found. Conclusions OCT appears more precise and less......Background Accurate assessment of tumour size is important when planning treatment of nonmelanoma skin cancer (NMSC). Imaging with optical coherence tomography (OCT) has the potential to diagnose and measure depth of NMSC. Objectives To compare accuracy of mean tumour thickness measurement in NMSC...... tumours values on the quality and penetration depth in OCT images was estimated. Methods In total, 93 patients were scanned...

  12. Ultrasound measurement of bladder wall thickness is associated with the overactive bladder syndrome.

    Science.gov (United States)

    Panayi, D C; Tekkis, P; Fernando, R; Hendricken, C; Khullar, V

    2010-09-01

    To assess the relationship between mean bladder wall thickness and components of the overactive bladder (OAB syndrome). Women attending urogynaecology clinic was categorized into overactive bladder syndrome, stress urinary incontinence (SUI), and mixed urinary continence (MUI) according to International Continence Society (ICS) definitions based on symptom history. Women completed a bladder diary, visual analog score (VAS) for urgency, and the mean bladder wall thickness (BWT) was determined. Comparison was made between the mean BWT and symptom history, daytime frequency, nocturia, VAS scores. Three hundred seventy-nine women were recruited to the study with a mean age of 56 years (range: 24-92 years). The mean bladder wall thickness did not show any age-related difference. Of these women 138/379 (36%) reported overactive bladder symptoms (mean BWT = 5.6 mm) 75/379 (20%) gave a history of stress urinary incontinence (mean BWT = 4.7 mm), and 166/379 (44%) had mixed urinary incontinence (mean BWT = 5.4). Women with nocturia >1 had mean BWT 5.6 mm, with nocturia 7 had mean BWT 5.7 mm and those 5 mm (P < 0.001). Mean BWT is associated with a symptom history of OAB and MUI, higher daytime and nightime frequency, and higher VAS scores. © 2010 Wiley-Liss, Inc.

  13. Uncertainty assessment in measurement of myotube thickness in cells culture treated with and without therapeutic ultrasound

    International Nuclear Information System (INIS)

    Abrunhosa, V M; Alvarenga, A V; Costa-Félix, R P B; Costa, M L; Mermelstein, C

    2015-01-01

    Effectiveness of an ultrasound treatment shall be assessed by experiments. A reliable cell culture protocol is available and spatial discrepancies could arise. To assure if the spatial difference are relevant or not, and how they should be dealt with, an uncertainty model for the treatment result is a metrological reliable solution. The present work reports a metrological approach to assess myotube thickness and to validate a primary cell culture of muscle after a therapeutic ultrasound treatment, comparing it with a control group. The results reinforced the importance of such approach and show an efficacy of treatment on myotube differentiation

  14. Measurement of oil film thickness and friction force on a guide shoe bearing

    DEFF Research Database (Denmark)

    Vølund, Anders

    2002-01-01

    An experimental program was carried out in order to reveal oil film thickness, and friction force of the guide shoe bearing of a large two stroke marine diesel engine. The experiment was conducted on a full size engine located at the research facility at MAN B&W Diesel A/S. The experiment...... was conducted such that the influence from the experiment on the characteristics were as small as possible. The objective of the experiment was to determine the frictional loss of this bearing and to check whether a suggested numerical model was applicable or not. Some future aspects for this bearing...

  15. Validation of a model-based measurement of the minimum insert thickness of knee prostheses: a retrieval study.

    Science.gov (United States)

    van IJsseldijk, E A; Harman, M K; Luetzner, J; Valstar, E R; Stoel, B C; Nelissen, R G H H; Kaptein, B L

    2014-10-01

    Wear of polyethylene inserts plays an important role in failure of total knee replacement and can be monitored in vivo by measuring the minimum joint space width in anteroposterior radiographs. The objective of this retrospective cross-sectional study was to compare the accuracy and precision of a new model-based method with the conventional method by analysing the difference between the minimum joint space width measurements and the actual thickness of retrieved polyethylene tibial inserts. Before revision, the minimum joint space width values and their locations on the insert were measured in 15 fully weight-bearing radiographs. These measurements were compared with the actual minimum thickness values and locations of the retrieved tibial inserts after revision. The mean error in the model-based minimum joint space width measurement was significantly smaller than the conventional method for medial condyles (0.50 vs 0.94 mm, p model-based measurements was less than 10 mm in the medial direction in 12 cases and less in the lateral direction in 13 cases. The model-based minimum joint space width measurement method is more accurate than the conventional measurement with the same precision. Cite this article: Bone Joint Res 2014;3:289-96. ©2014 The British Editorial Society of Bone & Joint Surgery.

  16. The effects of laser-sheet thickness on dissipation measurements in turbulent non-reacting jets and jet flames

    International Nuclear Information System (INIS)

    Kaiser, Sebastian A; Frank, Jonathan H

    2011-01-01

    The effects of laser-sheet thickness on planar laser measurements of scalar gradients in turbulent flows are studied. Experiments are performed in the near field of a turbulent, non-premixed, axisymmetric jet flame and in the near field of a non-reacting, isothermal turbulent jet. Laser Rayleigh scattering provides two-dimensional measurements of the instantaneous temperature and mixture fraction fields in the flame and non-reacting jet, respectively. The effect of spatial resolution on measurements of the mean dissipation and the power spectral density of axial temperature and mixture-fraction gradients is examined. The effect of varying the laser-sheet thickness is compared to that of spatial filtering within the image plane. Measurements of the mean dissipation and power spectral density are significantly less sensitive to resolution degradation in the non-differentiated dimensions than in the differentiated dimension. For example, on the jet flame centreline, the dissipation-cut-off microscale, which is determined from the measured power spectral density, is overestimated by 9% when the beam-waist thickness is increased from a 1/e-squared width of 160 µm to 624 µm. In contrast, spatial filtering along the direction of differentiation with a smoothing kernel of 624 µm width produces a bias of 76% in the cut-off microscale. These results experimentally confirm the theoretical analysis of previous studies. A simple spatial model illustrates the origin of this difference and approximately predicts its magnitude for both planar and line measurements. A criterion for matching in-plane and out-of-plane resolution is established. For many planar gradient measurements, considerably less out-of-plane resolution is needed than in-plane resolution. The combined effects of noise and spatial averaging on the dissipation measurements are also briefly examined

  17. National Beef Market Basket Survey - 2006: External fat thickness measurements and separable component determinations for beef from US retail establishments.

    Science.gov (United States)

    Mason, C L; Nicholson, K L; Brooks, J C; Delmore, R J; Henning, W R; Johnson, D D; Lorenzen, C L; Maddock, R J; Miller, R K; Morgan, J B; Wasser, B E; Gwartney, B L; Harris, K B; Griffin, D B; Hale, D S; Savell, J W

    2009-02-01

    A market basket survey for beef retail cut composition at the retail level (four stores each from two chains in each city) was conducted in 11 US cities from January to March 2006. Beef cuts (n=17,495) were measured for external fat thickness with cuts from the chuck (0.05cm), round (0.05cm), and miscellaneous (0.04cm) having less (Pmarketing purposes.

  18. Thickness measurement of soft thin films on periodically patterned magnetic substrates by phase difference magnetic force microscopy.

    Science.gov (United States)

    Passeri, D; Dong, C; Angeloni, L; Pantanella, F; Natalizi, T; Berlutti, F; Marianecci, C; Ciccarello, F; Rossi, M

    2014-01-01

    The need for accurate measurement of the thickness of soft thin films is continuously encouraging the development of techniques suitable for this purpose. We propose a method through which the thickness of the film is deduced from the quantitative measurement of the contrast in the phase images of the sample surface acquired by magnetic force microscopy, provided that the film is deposited on a periodically patterned magnetic substrate. The technique is demonstrated by means of magnetic substrates obtained from standard floppy disks. Colonies of Staphylococcus aureus adherent to such substrates were used to obtain soft layers with limited lateral (a few microns) and vertical (hundreds of nanometers) size. The technique is described and its specific merits, limitations and potentialities in terms of accuracy and measurable thickness range are discussed. These parameters depend on the characteristics of the sensing tip/cantilever as well as of the substrates, the latter in terms of spatial period and homogeneity of the magnetic domains. In particular, with the substrates used in this work we evaluated an uncertainty of about 10%, a limit of detection of 50-100 nm and an upper detection limit (maximum measurable thickness) of 1 μm, all obtained with standard lift height values (50-100 nm). Nonetheless, these parameters can be easily optimized by selecting/realizing substrates with suitable spacing and homogeneity of the magnetic domains. For example, the upper detection limit can be increased up to 25-50 μm while the limit of detection can be reduced to a few tens of nanometers or a few nanometers. © 2013 Elsevier B.V. All rights reserved.

  19. The effect of voxel size on the measurement of mandibular thickness in cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Ehsan Hekmatian

    2014-01-01

    Full Text Available Background: Cone-beam computed tomography (CBCT is a new imaging technology that has been widely used in implantology, oral and maxillofacial surgery and orthodontics. This method provides 3-D images that are composed of voxel, which is the smallest image unit, and determines image resolution. Smaller voxel is associated with the higher resolution and also greater radiation exposure. This study was aimed to find out the effect of voxel size on the measurement of mandibular thickness. Materials and Methods: Using voxel sizes of 0.30 mm and 0.15 mm, two CBCT protocols (protocol 1: Field of view (FOV of 15 cm, 85 kVp, 42 mAs, 0.15 mm voxel, 14 s scan time; protocol 2: FOV of 15 cm, 85 kVp, 10 mAs, 0.30 mm voxel, 14 s scan time were carried out on 16 dry human mandibles with permanent dentition. Mandibular thickness was measured at seven different sites (midline region, bilateral canine regions, bilateral mental foramen regions and bilateral molar regions. Analysis of variance was used for analysis of data using the Statistical Package for the Social Sciences version 20 (SPSS Inc., Chicago, IL, USA. P 0.05. Conclusion: Considering the insignificant differences of the mandibular thickness measurements using different voxel sizes, it would be more reasonable to use 0.30 mm voxel size instead of 0.15 mm voxel size to avoid unnecessary radiation exposure.

  20. Nonlinear optical refraction of Al2O3 single crystal doping with nickel nanoparticles measured by the Kerr-lens autocorrelation technique

    International Nuclear Information System (INIS)

    Yu, Xiangxiang; Wang, Yuhua; Wang, Yumei

    2014-01-01

    The nonlinear refraction of a nickel doped α-Al 2 O 3 single crystal was measured with a 800 nm pulse using the Kerr-lens autocorrelation technique. The sample was fabricated by ion implantation using a metal vapor vacuum arc ion source. The value of the nonlinear refractive index, n 2 , of the sample was determined to be 7.9 × 10 −16 cm 2 W −1 . The mechanisms of nonlinear refraction of the bulk material and the nanoparticles have been discussed through the UV–vis spectrum and supercontinuum spectra. (paper)

  1. Retinal thickness measured with optical coherence tomography and risk of disability worsening in multiple sclerosis

    DEFF Research Database (Denmark)

    Martinez-Lapiscina, Elena H; Arnow, Sam; Wilson, James A

    2016-01-01

    BACKGROUND: Most patients with multiple sclerosis without previous optic neuritis have thinner retinal layers than healthy controls. We assessed the role of peripapillary retinal nerve fibre layer (pRNFL) thickness and macular volume in eyes with no history of optic neuritis as a biomarker...... of disability worsening in a cohort of patients with multiple sclerosis who had at least one eye without optic neuritis available. METHODS: In this multicentre, cohort study, we collected data about patients (age ≥16 years old) with clinically isolated syndrome, relapsing-remitting multiple sclerosis......, and progressive multiple sclerosis. Patients were recruited from centres in Spain, Italy, France, Germany, Czech Republic, Netherlands, Canada, and the USA, with the first cohort starting in 2008 and the latest cohort starting in 2013. We assessed disability worsening using the Expanded Disability Status Scale...

  2. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  3. Contact lens in keratoconus

    Science.gov (United States)

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  4. Clinical lymph node staging-Influence of slice thickness and reconstruction kernel on volumetry and RECIST measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fabel, M., E-mail: m.fabel@rad.uni-kiel.de [Department of Diagnostic Radiology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, Haus 23, D-24105 Kiel (Germany); Wulff, A., E-mail: a.wulff@rad.uni-kiel.de [Department of Diagnostic Radiology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, Haus 23, D-24105 Kiel (Germany); Heckel, F., E-mail: frank.heckel@mevis.fraunhofer.de [Fraunhofer MeVis, Universitaetsallee 29, 28359 Bremen (Germany); Bornemann, L., E-mail: lars.bornemann@mevis.fraunhofer.de [Fraunhofer MeVis, Universitaetsallee 29, 28359 Bremen (Germany); Freitag-Wolf, S., E-mail: freitag@medinfo.uni-kiel.de [Institute of Medical Informatics and Statistics, Brunswiker Strasse 10, 24105 Kiel (Germany); Heller, M., E-mail: martin.heller@rad.uni-kiel.de [Department of Diagnostic Radiology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, Haus 23, D-24105 Kiel (Germany); Biederer, J., E-mail: juergen.biederer@rad.uni-kiel.de [Department of Diagnostic Radiology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, Haus 23, D-24105 Kiel (Germany); Bolte, H., E-mail: hendrik.bolte@ukmuenster.de [Department of Nuclear Medicine, University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebaeude A1, D-48149 Muenster (Germany)

    2012-11-15

    Purpose: Therapy response evaluation in oncological patient care requires reproducible and accurate image evaluation. Today, common standard in measurement of tumour growth or shrinkage is one-dimensional RECIST 1.1. A proposed alternative method for therapy monitoring is computer aided volumetric analysis. In lung metastases volumetry proved high reliability and accuracy in experimental studies. High reliability and accuracy of volumetry in lung metastases has been proven. However, other metastatic lesions such as enlarged lymph nodes are far more challenging. The aim of this study was to investigate the reproducibility of semi-automated volumetric analysis of lymph node metastases as a function of both slice thickness and reconstruction kernel. In addition, manual long axis diameters (LAD) as well as short axis diameters (SAD) were compared to automated RECIST measurements. Materials and methods: Multislice-CT of the chest, abdomen and pelvis of 15 patients with lymph node metastases of malignant melanoma were included. Raw data were reconstructed using different slice thicknesses (1-5 mm) and varying reconstruction kernels (B20f, B40f, B60f). Volume and RECIST measurements were performed for 85 lymph nodes between 10 and 60 mm using Oncology Prototype Software (Fraunhofer MEVIS, Siemens, Germany) and were compared to a defined reference volume and diameter by calculating absolute percentage errors (APE). Variability of the lymph node sizes was computed as relative measurement differences, precision of measurements was computed as relative measurement deviation. Results: Mean absolute percentage error (APE) for volumetric analysis varied between 3.95% and 13.8% and increased significantly with slice thickness. Differences between reconstruction kernels were not significant, however, a trend towards middle soft tissue kernel could be observed.. Between automated and manual short axis diameter (SAD, RECIST 1.1) and long axis diameter (LAD, RECIST 1.0) no

  5. Clinical lymph node staging—Influence of slice thickness and reconstruction kernel on volumetry and RECIST measurements

    International Nuclear Information System (INIS)

    Fabel, M.; Wulff, A.; Heckel, F.; Bornemann, L.; Freitag-Wolf, S.; Heller, M.; Biederer, J.; Bolte, H.

    2012-01-01

    Purpose: Therapy response evaluation in oncological patient care requires reproducible and accurate image evaluation. Today, common standard in measurement of tumour growth or shrinkage is one-dimensional RECIST 1.1. A proposed alternative method for therapy monitoring is computer aided volumetric analysis. In lung metastases volumetry proved high reliability and accuracy in experimental studies. High reliability and accuracy of volumetry in lung metastases has been proven. However, other metastatic lesions such as enlarged lymph nodes are far more challenging. The aim of this study was to investigate the reproducibility of semi-automated volumetric analysis of lymph node metastases as a function of both slice thickness and reconstruction kernel. In addition, manual long axis diameters (LAD) as well as short axis diameters (SAD) were compared to automated RECIST measurements. Materials and methods: Multislice-CT of the chest, abdomen and pelvis of 15 patients with lymph node metastases of malignant melanoma were included. Raw data were reconstructed using different slice thicknesses (1–5 mm) and varying reconstruction kernels (B20f, B40f, B60f). Volume and RECIST measurements were performed for 85 lymph nodes between 10 and 60 mm using Oncology Prototype Software (Fraunhofer MEVIS, Siemens, Germany) and were compared to a defined reference volume and diameter by calculating absolute percentage errors (APE). Variability of the lymph node sizes was computed as relative measurement differences, precision of measurements was computed as relative measurement deviation. Results: Mean absolute percentage error (APE) for volumetric analysis varied between 3.95% and 13.8% and increased significantly with slice thickness. Differences between reconstruction kernels were not significant, however, a trend towards middle soft tissue kernel could be observed.. Between automated and manual short axis diameter (SAD, RECIST 1.1) and long axis diameter (LAD, RECIST 1.0) no

  6. In situ measurement using FBGs of process-induced strains during curing of thick glass/epoxy laminate plate

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Hattel, Jesper Henri

    2012-01-01

    Bragg grating sensors are used to monitor process-induced strains during vacuum infusion of a thick glass/epoxy laminate. The measured strains are compared with predictions from a cure hardening instantaneous linear elastic (CHILE) thermomechanical numerical model where different mechanical boundary...... predicts the experimental transverse strains well when a tied boundary condition at the tool/part interface is used and the tool thermal expansion is taken into account. However, the CHILE approach is shown to overestimate residual strains after demoulding because of the shortcomings of the model...... conditions are employed. The accuracy of the CHILE model in predicting process-induced internal strains, in what is essentially a viscoelastic boundary value problem, is investigated. A parametric study is furthermore performed to reveal the effect of increasing the laminate thickness. The numerical model...

  7. Measurement of Acute Changes in Choroid Thickness in Healthy Eyes During Posture Change Using Optical Coherence Tomography

    Science.gov (United States)

    Ferguson, Connor R.; Lee, Stuart M. C.; Stenger, Michael B.; Laurie, Steven S.

    2015-01-01

    The Visual Impairment and Intracranial Pressure (VIIP) syndrome affects 60% of astronauts returning from long-duration missions and is characterized by structural and functional changes of the eye (3). Upon entry into weightlessness, approximately two liters of fluid translocates from the lower body to the thorax and cephalad regions, potentially contributing to elevated intracranial and intraocular pressures. The choroid is the vasculature that supplies blood flow to the posterior part of the retina and has limited autoregulation. As a consequence these vessels may engorge during a cephalad fluid shift, contributing to structural changes in the retina. The purpose of this experiment was to quantify changes in choroid thickness during a fluid shift. In order to fulfill this objective, it was also necessary to improve the measurement technique for assessing choroid thickness.

  8. Carotid intima-media thickness measurement through semi-automated detection software and analysis of vascular walls.

    Science.gov (United States)

    Novo, G; Di Miceli, R; Orlando, D; Lunetta, M; Pugliesi, M; Fiore, M; Spatafora, P; Novo, S

    2013-06-01

    The aim of the present study was to compare the semi-automatic measurement of carotid intima thickness (RFQIMT - Esaote, Italy), with the conventional method. We enrolle 81 patients, mean age 46 years ±15, with no history of cardio-cerebrovascular events and we assessed the traditional cardiovascular risk factors. We examined the IMT of the common carotid artery with manual and RFQIMT method (based on the "Radio Frequency" signal), according to the ASE protocol. Semi-automatic measurement was on average lower than manual measurement (617 μm ±191 vs. 676 μm ± 222) with a statistically significant difference (Pmeasurements, the values of RFQIMT increased with increasing age and presence of cardiovascular risk factors. The RFQIMT measurement was, on average, lower than manual measurement, this means that probably, age- and gender-related reference values of RFQIMT need to be revised.

  9. Correlation between magnetic resonance imaging and ultrasound measurements of eye muscle thickness in thyroid-associated orbitopathy.

    Science.gov (United States)

    Karhanova, Marta; Kovar, Radim; Frysak, Zdenek; Sin, Martin; Zapletalova, Jana; Rehak, Jiri; Herman, Miroslav

    2015-06-01

    To compare ultrasound (US) and magnetic resonance imaging (MRI) measurements of horizontal eye muscle thickness in patients with thyroid-associated orbitopathy (TAO) and to compare these measurements according to the phase of the disease, the severity of exophthalmos, and the experience of the investigator. A total of 180 orbits of adult patients with TAO were investigated from May 2007 to December 2012. In addition to their general ophthalmic examination, all patients underwent ultrasonographic measurement of horizontal eye muscle thickness with the B-scan technique and MRI examination of the orbit. Correlations between values obtained by US and MRI were determined for different subgroups according to disease activity (active, inactive), exophthalmos values (Hertel 22 mm), and the time period of examination (2007-2009; 2010-2012). Positive moderate correlation between US and MRI values for the medial rectus muscle (MRM; r = 0.690) and for the lateral rectus muscle (LRM; r = 0.572) was found. Significantly higher correlation was found for the MRM (P < 0.0001) and the LRM (P = 0.0008) in the time period 2010-2012 than in that of 2007-2009. Increasing correlation was found for MRM with increasing values of exophthalmos but this increase was not statistically significant. In the active phase of the disease compared to the inactive phase, statistically significant increased correlation (P = 0.019) was found for the LRM. Ultrasonographic measurement of horizontal eye muscles thickness in TAO moderately correlates with values obtained using MRI. The accuracy of ultrasonographic measurements in particular increases with the experience of the investigator.

  10. Effect of corneal thickness on intraocular pressure measurements with the pneumotonometer, Goldmann applanation tonometer, and Tono-Pen.

    Science.gov (United States)

    Bhan, Archana; Browning, Andrew C; Shah, Sunil; Hamilton, Robin; Dave, Dinesh; Dua, Harminder S

    2002-05-01

    To compare intraocular pressure (IOP) measurements of the Ocular Blood Flow (OBF) pneumotonometer, Goldmann applanation tonometer, and Tono-Pen in eyes with normal corneas of various thicknesses. IOP was measured with an OBF pneumotonometer, Tono-Pen and Goldmann applanation tonometer in random order in 181 eyes with normal corneas. Central corneal thickness (CCT) was measured using an ultrasonic pachymeter after all IOP determinations had been made. Right and left eyes were analyzed separately for statistical purposes. With all instruments, IOP varied with CCT, even though the variation in IOP was large. Readings with the OBF pneumotonometer showed a mean increase in IOP with increasing CCT of 0.28 mm Hg/10 microm, an increase of 0.23 mm Hg/10 microm with the Goldmann tonometer, and of 0.10 mm Hg/10 microm with the Tono-Pen. The OBF pneumotonometer consistently recorded comparatively higher IOPs than the other two instruments. The Tono-Pen is least affected by CCT when used to measure IOP in eyes with normal corneas. The OBF pneumotonometer appears to be more affected by variation in CCT than the Goldmann tonometer. This is contrary to expectations, based on the mechanism of measurement of IOP of the OBF pneumotonometer.

  11. Design of electrohydrodynamic lens for stabilizing of eletrohydrodynamic jet printing

    International Nuclear Information System (INIS)

    Park, Sung-Eun; Lee, Dae-Young; Kim, Sang-Yoon; Shin, Yoon-Soo; Hwang, Jungho; Yu, Tae-U

    2008-01-01

    The generation of micro patterns from conductive material suspensions is gaining significant interests for its usages in the fabrication of flexible display elements and flexible printed circuit boards. In this paper, we presented the results of line patterns of silver nanoparticles obtained by using various types of focusing lenses for electrohydrodynamic jet printing. The pattern widths were measured as 80∼100 μm when the electrohydrodynamic lens having a cone-type inner hole and a cone-type outer wall was used. Electric field strengths were calculated by a commercial solver packages for the four types of electrohydrodynamic lenses. A lens having a cone-type inner hole and a cone-type outer wall of thinner thickness was found to be the best design.

  12. Sonographically measured perirenal fat thickness: an early predictor of atherosclerosis in HIV-1-infected patients receiving highly active antiretroviral therapy?

    Science.gov (United States)

    Grima, Pierfrancesco; Guido, Marcello; Zizza, Antonella; Chiavaroli, Roberto

    2010-05-01

    The aim of our study was to evaluate whether perirenal fat thickness (PRFT), a parameter of central obesity, is related to carotid intima-media thickness (IMT), an index of atherosclerosis in human immunodeficiency virus (HIV)-1-infected patients. We enrolled 70 consecutive HIV-1-infected patients receiving highly active antiretroviral therapy for more than 12 months, in a prospective cohort study. Sonographically measured PRFT and carotid IMT, as well as serum metabolic parameters, were evaluated. PRFT and IMT were measured using 3.75-MHz convex and 7.5-MHz linear probes, respectively. The mean PRFT and IMT in HIV-1-infected patients with visceral obesity was significantly greater than those in patients without it (p or= 0.9 mm (sensitivity 83.3%, specificity 83.9%). Subjects with visceral obesity had a progressively increasing carotid IMT on the 12-month measurement (p < 0.05). Our data demonstrated that PRFT measurement could be used as an early predictor of IMT increase in HIV-1-infected patients receiving highly active antiretroviral therapy.

  13. In situ measurement of humidity induced changes in the refractive index and thickness of polyethylene glycol thin films

    Science.gov (United States)

    Bilen, Bukem; Skarlatos, Yani; Aktas, Gulen; Inci, M. Naci; Dispinar, Tugba; Kose, M. Merve; Sanyal, Amitav

    2008-11-01

    Humidity induced changes in the refractive index and thickness of polyethylene glycol (PEG) thin films are in situ determined by optical waveguide spectroscopy. PEG brushes are covalently attached to the surface of a thin gold film on a borosilicate crown glass (BK7) using a grafting-from chemical synthesis technique. The measurements are carried out in an attenuated total internal reflection setup. At low humidity levels, both the refractive index and the thickness change gradually due to swelling of the PEG thin films upon water intake. At around 80% relative humidity, a steep decrease in the refractive index and a steep increase in the thickness are observed as a result of a phase change from a semicrystalline state to a physical gel state. The hydrogenation of PEG films causes a less pronounced phase change from a semicrystalline state to a gel state. Due to fewer ether oxygen atoms available for the water molecules to make hydrogen bonding, the polymer has a more stable structure than before and the phase change is observed to shift to higher humidity levels. It is discussed that such a humidity induced change in the index of refraction can be utilized in constructing of a PEG based humidity sensor.

  14. Development of nondestructive hybrid measuring method for three-dimensional residual stress distribution of thick welded joint. Hybrid measuring method of inherent strain method and neutron diffraction method

    International Nuclear Information System (INIS)

    Nakacho, Keiji; Kasahara, Norifumi; Tamura, Ryota

    2012-01-01

    The measuring methods of the residual stress are classified into destructive one and nondestructive one. The inherent strain method (ISM) is destructive one. The neutron diffraction method (NDM) is nondestructive one. But the measurable depth is limited within about 20 mm and the method cannot measure the weld zone, without destruction of the object. So, in this study, the hybrid measuring method has been developed, by combining the ISM and the NDM. The theory of the hybrid method is the same as the ISM. In the analysis, the strains measured by the NDM without destruction are used. This hybrid measuring method is a true nondestructive measuring method for a thick welded joint. The applicability of the hybrid method has been verified by simulation, using a butt welded joint of thick pipes. In the simulation, the reliable order of the strains measured by the present NDM is very important, and was considered as 10 micro. The measurable regions by the present NDM were assumed. Under the above conditions, the data (the residual elastic strains assumed to be measured by the NDM) were made, and used in the ISM. As a result of such simulation, it has been cleared that the estimated residual stress has very high accuracy, if enough data are used. The required number of data is less than the ISM. (author)

  15. Measurement of cement thickness under lithium disilicate crowns using an impression material technique.

    Science.gov (United States)

    Reich, Sven; Uhlen, Sophia; Gozdowski, Stephan; Lohbauer, Ulrich

    2011-08-01

    According to the literature, marginal gaps below 120 μm are recommended for conventionally cemented crown restorations. Therefore, the null hypothesis tested was as follows: the upper bound of the 95% confidence interval of the marginal accuracy of chair-side generated lithium disilicate crowns lies below 120 μm. Prior to definite insertion, the accuracy of 20 lithium disilicate crowns (e.max CAD LT) was evaluated by a replica technique. A light-body silicone was used to document the gap between crown and abutment. The thickness of the light-body silicone layer was examined under microscope (MM40, Nikon Corp., Tokyo, Japan; magnification, ×50) at four different landmarks (LM): LM1 = marginal discrepancy, LM2 = mid-axial discrepancy of the inner crown surface, LM3 = axio-occlusal discrepancy, and LM4 = mid-occlusal discrepancy. At LM1, the mean marginal discrepancy revealed 100 μm (SD, ±61 μm); the median was 81 μm. The lower bound of the 95% confidence interval was 90 μm, and the upper bound was 110 μm. The means of internal gaps at LM2, LM3, and LM4 showed 148 μm (SD, ±61 μm), 227 μm (SD, ±83 μm), and 284 μm (SD, ±95 μm), respectively. The lower bounds of the 95% confidence interval revealed values between 137 μm (LM2) and 269 μm (LM4). The upper bounds were between 158 μm (LM2) and 300 μm (LM4). The null hypothesis was not rejected. Within the limits of the study, the chair-side generated lithium disilicate crowns exhibited a sufficient clinical accuracy.

  16. The effect of model inclination during fabrication on mouthguard calliper-measured and CT scan-assessed thickness.

    Science.gov (United States)

    Farrington, Timothy; Coward, Trevor; Onambele-Pearson, Gladys; Taylor, Rebecca L; Earl, Philip; Winwood, Keith

    2016-06-01

    Excessive material thinning has been observed in the production of custom-made mouthguards in a number of studies, due to production anomalies that may lead to such thinning. This study investigated thinning material patterns of custom-made mouthguards when the anterior angulation of dental model was increased during the thermoforming process. A total of 60 samples of mouthguard blanks were thermoformed on identical maxillary models under four anterior inclination conditions (n = 4 × 15): control 0, 15, 30 and 45°. Each mouthguard sample was measured, using an electronic calliper gauge at three anatomical points (anterior labial sulcus, posterior occlusion and posterior lingual). Mouthguards were then CT scanned to give a visual representation of the surface thickness. Data showed a significant difference (P < 0.005) in the anterior mouthguard thickness between the four levels of anterior inclination, with the 45° inclination producing the thickest mouthguards, increasing the mean anterior thickness by 75% (2.8 mm, SD: 0.16) from the model on a flat plane (1.6 mm, SD: 0.34). Anterior model inclination of 30 and 45° inclinations increased consistencies between the thickest and thinnest mouthguards in the anterior region of these sample groups. This study highlights the importance of standardizing the thermoforming process, as this has a significant effect on the quality and material distribution of the resultant product. In particular, greater model inclination is advised as this optimizes the thickness of the anterior sulcus of the mouthguard which may be more prominently at risk from sport-related impact. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Reliability of routine clinical measurements of neonatal circumferences and research measurements of neonatal skinfold thicknesses: findings from the Born in Bradford study

    Science.gov (United States)

    West, Jane; Manchester, Ben; Wright, John; Lawlor, Debbie A; Waiblinger, Dagmar

    2011-01-01

    Summary West J, Manchester B, Wright J, Lawlor DA, Waiblinger D. Reliability of routine clinical measurements of neonatal circumferences and research measurements of neonatal skinfold thicknesses: findings from the Born in Bradford study. Paediatric and Perinatal Epidemiology 2011. Assessing neonatal size reliably is important for research and clinical practice. The aim of this study was to examine the reliability of routine clinical measurements of neonatal circumferences and of skinfold thicknesses assessed for research purposes. All measurements were undertaken on the same population of neonates born in a large maternity unit in Bradford, UK. Technical error of measurement (TEM), relative TEM and the coefficient of reliability are reported. Intra-observer TEMs for routine circumference measurements were all below 0.4 cm and were generally within ±2-times the mean. Inter-observer TEM ranged from 0.20 to 0.36 cm for head circumference, 0.19 to 0.39 cm for mid upper arm circumference and from 0.39 to 0.77 cm for abdominal circumference. Intra and inter-observer TEM for triceps skinfold thickness ranged from 0.22 to 0.35 mm and 0.15 to 0.54 mm, respectively. Subscapular skinfold thickness TEM values were 0.14 to 0.25 mm for intra-observer measurements and 0.17 to 0.63 mm for inter-observer measurements. Relative TEM values for routine circumferences were all below 4.00% but varied between 2.88% and 14.23% for research skinfold measurements. Reliability was mostly between 80% and 99% for routine circumference measurements and ≥70% for most research skinfold measurements. Routine clinical measurements of neonatal circumferences are reliably assessed in Bradford. Assessing skinfolds in neonates has variable reliability, but on the whole is good. The greater intra-observer, compared with inter-observer, reliability for both sets of measurements highlights the importance of having a minimal number of assessors whenever possible. PMID:21281329

  18. Influence of the chemical shift artifact on measurements of compact bone thickness in equine distal limb MR images.

    Science.gov (United States)

    Dimock, Abigail N; Spriet, Mathieu

    2010-01-01

    The effect of the chemical shift artifact, resulting from misregistration or phase cancellation at the interface between compact and trabecular bone, on apparent bone thickness was quantified in six isolated equine limbs. Sagittal T1-weighted spin echo (SE) and in-phase three-dimensional spoiled gradient echo (SPGR) images were acquired twice with a 1.5 T magnetic resonance (MR) unit, switching the frequency encoding direction between acquisitions. Out-of-phase SPGR images were also obtained. MR images with different frequency encoding directions were compared with each other and to radiographs made from corresponding 3-mm-bone sections. Compact bone thickness was significantly different when comparing images acquired with different frequency encoding directions for both SE and SPGR sequences. Significant differences were identified in the frequency but not the phase encoding direction when measurements of compact bone in MR images were compared with measurements obtained from thin section radiographs for the majority of surfaces studied (P 0.05). Measurements of compact bone from out-of-phase SPGR sequences were significantly different than from in-phase sequences (P echo sequences.

  19. Effect of central corneal thickness and radius of the corneal curvature on intraocular pressure measured with the Tono-Pen and noncontact tonometer in healthy schoolchildren.

    Science.gov (United States)

    Yildirim, Nilgun; Sahin, Afsun; Basmak, Hikmet; Bal, Cengiz

    2007-01-01

    To determine the effect of central corneal thickness and radius of the corneal curvature on intraocular pressure (IOP) measurements using the Tono-Pen and a noncontact tonometer in healthy Turkish schoolchildren. IOP was measured with the Tono-Pen and a noncontact tonometer in 602 eyes of 602 healthy schoolchildren with a mean age of 10.1 +/- 1.6 years. Central corneal thickness was measured using an ultrasonic pachymeter after all IOP determinations had been made. The effect of central corneal thickness, radius of the corneal curvature, and sex on measured IOP was explored by linear regression analysis. The mean central corneal thickness was found to be 564.92 +/- 32 microm. The mean IOP readings were 17.9 +/- 2 mm Hg using the Tono-Pen, and 16.7 +/- 2 mm Hg using a noncontact tonometer. The Tono-Pen measured IOP values slightly greater than the noncontact tonometer (P < .0001). A significant association between measured IOP and central corneal thickness was found with each device. The IOP increased 2.1 and 4.2 mm Hg with every 100-microm increase in central corneal thickness for the Tono-Pen and the noncontact tonometer, respectively. The dependence of IOP on central corneal thickness did not differ between boys and girls. There was a significant association between the Tono-Pen and noncontact tonometer differences and central corneal thickness; the noncontact tonometer tended to overestimate IOP in eyes with thicker corneas. The Tono-Pen readings appeared to be less affected by corneal thickness than those of the noncontact tonometer. The corneal radius of curvature had no significant effect on measured IOP with each device. Because the Tono-Pen was relatively easy to use and less affected by corneal thickness, it may be an alternative method for measuring IOP in children.

  20. The endomyometrial thickness measurement for abnormal implantation evaluation by pelvic sonography.

    Science.gov (United States)

    Lewiss, Resa E; Shaukat, Nadia M; Saul, Turandot

    2014-07-01

    Emergency physicians, obstetrician-gynecologists, and other medical specialists use pelvic sonography when caring for patients presenting with early pregnancy-related symptoms. A thin endomyometrial mantle and eccentric placement of a gestational sac should raise the suspicion for an abnormally implanted pregnancy. In such cases, an interstitial ectopic pregnancy or a cornual pregnancy, two clinically distinct entities, must be considered. This article reviews the literature and guidelines on the sonographic measurement of the endomyometrial mantle as a criterion for determining a pregnancy at risk for an abnormal implantation location. We sought to clarify the history and evolution of this measurement to determine what should be considered an abnormal measurement and to understand its diagnostic utility and management implications for the clinician using sonography. © 2014 by the American Institute of Ultrasound in Medicine.

  1. Development of the neutron diffraction method for stress measurements in thick steel samples.

    Science.gov (United States)

    Em, V. T.; Woo, W.; Seong, B.-S.; Mikula, P.

    2016-09-01

    The results of development of neutron method for stress measurements in bulk steel components are considered. Enhancement of the maximum available path length (∼⃒85mm) was achieved by using optimized bent perfect silicon crystal monochromators, position sensitive detectors and neutron wavelengths, corresponding to the minimums of neutron total cross section near Bragg edges.

  2. Ultrasonic measurements of undamaged concrete layer thickness in a deteriorated concrete structure

    NARCIS (Netherlands)

    Demcenko, A.; Visser, Roy; Akkerman, Remko

    2016-01-01

    Ultrasonic wave propagation in deteriorated concrete structures was studied numerically and experimentally. Ultrasonic single-side access immersion pulse-echo and diffuse field measurements were performed in deteriorated concrete structures at 0.5 MHz center frequency. Numerically and experimentally

  3. Normalization of cortical thickness measurements across different T1 magnetic resonance imaging protocols by novel W-Score standardization.

    Science.gov (United States)

    Chung, Jinyong; Yoo, Kwangsun; Lee, Peter; Kim, Chan Mi; Roh, Jee Hoon; Park, Ji Eun; Kim, Sang Joon; Seo, Sang Won; Shin, Jeong-Hyeon; Seong, Joon-Kyung; Jeong, Yong

    2017-10-01

    The use of different 3D T1-weighted magnetic resonance (T1 MR) imaging protocols induces image incompatibility across multicenter studies, negating the many advantages of multicenter studies. A few methods have been developed to address this problem, but significant image incompatibility still remains. Thus, we developed a novel and convenient method to improve image compatibility. W-score standardization creates quality reference values by using a healthy group to obtain normalized disease values. We developed a protocol-specific w-score standardization to control the protocol effect, which is applied to each protocol separately. We used three data sets. In dataset 1, brain T1 MR images of normal controls (NC) and patients with Alzheimer's disease (AD) from two centers, acquired with different T1 MR protocols, were used (Protocol 1 and 2, n = 45/group). In dataset 2, data from six subjects, who underwent MRI with two different protocols (Protocol 1 and 2), were used with different repetition times, echo times, and slice thicknesses. In dataset 3, T1 MR images from a large number of healthy normal controls (Protocol 1: n = 148, Protocol 2: n = 343) were collected for w-score standardization. The protocol effect and disease effect on subjects' cortical thickness were analyzed before and after the application of protocol-specific w-score standardization. As expected, different protocols resulted in differing cortical thickness measurements in both NC and AD subjects. Different measurements were obtained for the same subject when imaged with different protocols. Multivariate pattern difference between measurements was observed between the protocols. Classification accuracy between two protocols was nearly 90%. After applying protocol-specific w-score standardization, the differences between the protocols substantially decreased. Most importantly, protocol-specific w-score standardization reduced both univariate and multivariate differences in the images while

  4. Laser-induced fluorescence measurement of the oil film thickness in an internal combustion engine

    Science.gov (United States)

    Ostroski, Greg M.; Ghandhi, Jaal B.

    1997-11-01

    The use of a fluorescent dopant molecule to enhance the natural fluorescence of motor oils, and allow quantitative determination of temperature and film thickens in internal combustion engines has been investigated. Measurement of the fluorescence as a function of temperature were made with neat Mobil 1, and solutions of the dopant BTBP in mineral oil and Mobil 1. The fluorescence yield of neat Mobil 1 was found to vary by 30 percent over the temperature range explored, but the spectral characteristics, as measured with bandpass filters, were unaffected by temperature. The BTBP fluorescence was found to increase significantly with temperature, and it was found the narrower regions in the spectrum increased proportionally more than the fluorescence collected over the entire spectrum, allowing a determination of temperature to be made which can then be used to correct for the change in fluorescence yield. Solutions in Mobil 1 showed a smaller increase than that observed in mineral oil.

  5. Retinal nerve fibre layer thickness measured by Spectralis spectral-domain optical coherence tomography: The Beijing Eye Study.

    Science.gov (United States)

    Zhao, Liang; Wang, Yaxing; Chen, Chang X; Xu, Liang; Jonas, Jost B

    2014-02-01

    The aim of this study was to measure retinal nerve fibre layer thickness (RNFLT) and its associated factors in a population-based setting. The population-based Beijing Eye Study 2011 included 3468 individuals. The study participants underwent spectral-domain optical coherence tomography (Spectralis(®) ; Spectralis OCT)-assisted measurement of the RNFLT. For this study, exclusion criteria were glaucoma, pseudoexfoliation, best-corrected visual acuity of >0.5 logMAR, macular diseases, previous ocular surgery and known neurological diseases. The only inclusion criterion was an age of 50+ years. The inclusion criteria were fulfilled by 2548 participants. Mean RNFLT was 102 ± 11 μm. RNFLT was significantly (p optic disc size (p optic disc, larger rim, hyperopic refractive error, larger parapapillary beta zone and thicker subfoveal choroidal thickness. Independent of age and refractive error, the RNFL was thickest temporal inferiorly and thinnest temporally and nasally. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  6. Intraoperative corneal thickness measurements during corneal collagen cross-linking with isotonic riboflavin solution without dextran in corneal ectasia.

    Science.gov (United States)

    Cınar, Yasin; Cingü, Abdullah Kürşat; Sahin, Alparslan; Türkcü, Fatih Mehmet; Yüksel, Harun; Caca, Ihsan

    2014-03-01

    Abstract Objective: To monitor the changes in corneal thickness during the corneal collagen cross-linking procedure by using isotonic riboflavin solution without dextran in ectatic corneal diseases. The corneal thickness measurements were obtained before epithelial removal, after epithelial removal, following the instillation of isotonic riboflavin solution without dextran for 30 min, and after 10 min of ultraviolet A irradiation. Eleven eyes of eleven patients with progressive keratoconus (n = 10) and iatrogenic corneal ectasia (n = 1) were included in this study. The mean thinnest pachymetric measurements were 391.82 ± 30.34 µm (320-434 µm) after de-epithelialization of the cornea, 435 ± 21.17 µm (402-472 µm) following 30 min instillation of isotonic riboflavin solution without dextran and 431.73 ± 20.64 µm (387-461 µm) following 10 min of ultraviolet A irradiation to the cornea. Performing corneal cross-linking procedure with isotonic riboflavin solution without dextran might not induce corneal thinning but a little swelling throughout the procedure.

  7. Correlations between measures of executive attention and cortical thickness of left posterior middle frontal gyrus - a dichotic listening study

    Directory of Open Access Journals (Sweden)

    Lundervold Arvid

    2009-10-01

    Full Text Available Abstract Background The frontal lobe has been associated to a wide range of cognitive control functions and is also vulnerable to degeneration in old age. A recent study by Thomsen and colleagues showed a difference between a young and old sample in grey matter density and activation in the left middle frontal cortex (MFC and performance on a dichotic listening task. The present study investigated this brain behaviour association within a sample of healthy older individuals, and predicted a positive correlation between performance in a condition requiring executive attention and measures of grey matter structure of the posterior left MFC. Methods A dichotic listening forced attention paradigm was used to measure attention control functions. Subjects were instructed to report only the left or the right ear syllable of a dichotically presented consonant-vowel syllable pair. A conflict situation appears when subjects are instructed to report the left ear stimulus, caused by the conflict with the bottom-up, stimulus-driven right ear advantage. Overcoming this processing conflict was used as a measure of executive attention. Thickness and volumes of frontal lobe regions were derived from automated segmentation of 3D magnetic resonance image acquisitions. Results The results revealed a statistically significant positive correlation between the thickness measure of the left posterior MFC and performance on the dichotic listening measures of executive attention. Follow-up analyses showed that this correlation was only statistically significant in the subgroup that showed the typical bottom-up, stimulus-driven right ear advantage. Conclusion The results suggest that the left MFC is a part of an executive attention network, and that the dichotic listening forced attention paradigm may be a feasible tool for assessing subtle attentional dysfunctions in older adults.

  8. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  9. Measure Guideline: Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States); Baker, Peter [Building Science Corporation, Westford, MA (United States)

    2015-04-01

    This measure guideline provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ inches and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: fundamental building science principles relating to the use of exterior insulation on wall assemblies; design principles for tailoring this use to the specific project goals and requirements; and construction detailing to increase understanding about implementing the various design elements.

  10. Measure Guideline. Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States); Baker, Peter [Building Science Corporation, Westford, MA (United States)

    2015-04-09

    This measure guideline, written by the U.S. Department of Energy’s Building America team Building Science Corporation, provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ in. and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: (1) fundamental building science principles relating to the use of exterior insulation on wall assemblies; (2) design principles for tailoring this use to the specific project goals and requirements; and (3) construction detailing to increase understanding about implementing the various design elements.

  11. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes ...

  12. Comparison of Central Corneal Thickness Measurements Obtained by RTVue OCT, Lenstar, Sirius Topography, and Ultrasound Pachymetry in Healthy Subjects.

    Science.gov (United States)

    Şimşek, Ali; Bilak, Şemsettin; Güler, Mete; Çapkin, Musa; Bilgin, Burak; Reyhan, Ali Hakim

    2016-01-01

    To compare central corneal thickness (CCT) measurement results obtained by RTVue OCT, Lenstar, Sirius topography, and ultrasound pachymetry (UP) (OcuScan RxP Ophthalmic Ultrasound System, Alcon Laboratories) in healthy subjects. 256 eyes of 128 healthy subjects were included in the study. CCT measurements were obtained from the eyes for each subject using the UP, Lenstar, Sirius topography, and RTVue OCT instruments. Ultrasound pachymetry measurements were performed after the eyes were anesthetized with one drop of 0.5% proparacaine hydrochloride and were performed at the same day after 15 minutes after previous measurements. Of 128 participants, 84 were male and 44 were female with a mean age of 33.15 ± 12.95 years (ranging from 18 to 75 years). The mean CCTs for UP, Lenstar, Sirius topography, and RTVue OCT were 535.60 ± 35.15 (440,00-668,00); 532.63 ± 34.44 (449,00-650,00); 526.05 ± 36.45 (314,00-640,00); 525.89 ± 33.21 (437,00-646,00) µm, respectively. The mean CCT measurements were statistically different among the three groups (p = 0.002). CCT measurements obtained using RTVue-OCT were significantly thinner than those obtained using UP (p = 0.009). Sirius CCT measurements were also thinner than UP (p = 0.011). Mean CCT measurements between UP and Lenstar were similar (p = 0.769). Measurements with Lenstar (r = 0.849), Sirius topography (r = 0.883), and RTVue OCT (0.949) were highly correlated with UP measurements. RTVue OCT and Sirius topography significantly underestimated the CCT compared with UP. Although highly correlated, the measurement values with these devices are not directly interchangeable in clinical practice.

  13. Carotid intima-medial thickness measured on multiple ultrasound frames: evaluation of a DICOM-based software system

    Directory of Open Access Journals (Sweden)

    McQuillan Brendan M

    2007-09-01

    Full Text Available Abstract Background Carotid intima-media thickness (CIMT measured by B-mode ultrasonography is a marker of atherosclerosis and is commonly used as an outcome in intervention trials. We have developed DICOM-based software that measures CIMT rapidly on multiple end-diastolic image frames. The aims of this study were to compare the performance of our new software with older bitmap-based CIMT measurement software and to determine whether a ten-fold increase in the number of measurements used to calculate mean CIMT would improve reproducibility. Methods Two independent sonographers recorded replicate carotid scans in thirty volunteers and two blinded observers measured CIMT off-line using the new DICOM-based software and older bitmap-based software. A Bland-Altman plot was used to compare CIMT results from the two software programs and t-tests were used to compare analysis times. F-tests were used to compare the co-efficients of variation (CVs from a standard six-frame measurement protocol with CVs from a sixty-frame measurement protocol. Ordinary least products (OLP regression was used to test for sonographer and observer biases. Results The new DICOM-based software was much faster than older bitmap-based software (average measurement time for one scan 3.4 ± 0.6 minutes versus 8.4 ± 1.8 minutes, p Conclusion While the use of DICOM-based software significantly reduced analysis time, a ten-fold increase in the number of measurements used to calculate CIMT did not improve reproducibility. In addition, we found that observer biases caused differences in mean CIMT of a magnitude commonly reported as significant in intervention trials. Our results highlight the importance of good study design with concurrent controls and the need to ensure that no observer drift occurs between baseline and follow-up measurements when CIMT is used to monitor the effect of an intervention.

  14. Observation measurement and analysis on strata pressure of fully mechanized longwall caving face in special thick seam

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Wu, J.; Li, B.; Liu, S.; Liang, J. [China University of Mining and Technology (China). Beijing Graduate School

    1997-09-01

    This paper introduces a fully mechanized longwall caving mining face in Weijiadi Mine, Gansu Province. The seam to be mined was a special thick seam with potential outbursts of coal and gas and spontaneous combustion. The average thickness of the seam was 12 m. The seam was mined with a one-pass method. Due to the softness of the coal body and the roof and floor, the strata support and bearing area of the coal face had to be moved in advance, slowly when the gateways became seriously deformed. The slow advancing had provided a condition for the spontaneous combustion of the residual coal in the goaf. Through observation, measurement and analysis of the strata in the coal face; the results revealed a rational support with hydraulic powered supports mainly to control the roof and the coal face, the distance of the periodical strata pressure was 20 to 35 m. The support resistance of the one-pass caving face was higher than the slicing mining face. The conveyor gateway of the caving face was seriously deformed and an advanced support of the gateway should have been made. 6 figs.

  15. Magnetic Measurements as a Useful Tool for the Evaluation of Spatial Variability of the Arable Horizon Thickness

    Science.gov (United States)

    Fattakhova, Leysan; Shinkarev, Alexandr; Ryzhikh, Lyudmila; Kosareva, Lina

    2017-04-01

    In normal practice, the thickness of the arable horizon is determined on the basis of field morphological descriptions, allowing the subjectivity of perception and judgment at the crucial role of experience of the researcher. The subject of special interest are independent analytical and technically relatively simple in design approaches to the diagnosis of the lower boundary of the blended plowing the profiles part. Theoretical premises to use spectrophotometry and magnetometry to arable horizon depth diagnose is based on the concept of regular color and magnetic properties vertical differentiation in a profile of virgin soils. This work is devoted to the comparative assessment of the possibility to objectively and reliably diagnose the lower boundary of the arable horizon in gray forest soils by determining the color characteristics and the magnetic susceptibility of their layer-wise samples. It was shown with arable gray forest soil (Cutanic Luvisols (Anthric)) as example that the magnetic susceptibility profile distribution curves can provide more reliable and objective assessment of the arable horizon thickness spatial variability than the profile curves of the color characteristics in the CIELAB coordinates. Therefore, magnetic measurements can be a useful tool for the tillage erosion estimation in the monitoring of soil characteristics in connection with the development of precision agriculture technologies and the organizing of agricultural field plot experiments.

  16. Cortical thickness, surface area and volume measures in Parkinson's disease, multiple system atrophy and progressive supranuclear palsy.

    Directory of Open Access Journals (Sweden)

    Amanda Worker

    Full Text Available Parkinson's disease (PD, Multiple System Atrophy (MSA and Progressive Supranuclear Palsy (PSP are neurodegenerative diseases that can be difficult to distinguish clinically. The objective of the current study was to use surface-based analysis techniques to assess cortical thickness, surface area and grey matter volume to identify unique morphological patterns of cortical atrophy in PD, MSA and PSP and to relate these patterns of change to disease duration and clinical features.High resolution 3D T1-weighted MRI volumes were acquired from 14 PD patients, 18 MSA, 14 PSP and 19 healthy control participants. Cortical thickness, surface area and volume analyses were carried out using the automated surface-based analysis package FreeSurfer (version 5.1.0. Measures of disease severity and duration were assessed for correlation with cortical morphometric changes in each clinical group.Results show that in PSP, widespread cortical thinning and volume loss occurs within the frontal lobe, particularly the superior frontal gyrus. In addition, PSP patients also displayed increased surface area in the pericalcarine. In comparison, PD and MSA did not display significant changes in cortical morphology.These results demonstrate that patients with clinically established PSP exhibit distinct patterns of cortical atrophy, particularly affecting the frontal lobe. These results could be used in the future to develop a useful clinical application of MRI to distinguish PSP patients from PD and MSA patients.

  17. Further studies of contact lens motion during blinking.

    Science.gov (United States)

    Conway, H D; Knoll, H A

    1986-10-01

    Contact lens motion is felt to be of increasing importance in connection with debris elimination, particularly in extended wear lenses. Thus an improved analysis is made of a simple model for investigating the initial motion of a hard contact lens over the eye during blinking. It is shown that the assumption of constant tear film thickness is a reasonable one. This greatly simplifies the analysis. Various vertical force vs. time variations are considered and lens velocity/time graphs and maximum lens displacement calculated. These are in good agreement with the results of experiment.

  18. Particle swarm optimization applied to automatic lens design

    Science.gov (United States)

    Qin, Hua

    2011-06-01

    This paper describes a novel application of Particle Swarm Optimization (PSO) technique to lens design. A mathematical model is constructed, and merit functions in an optical system are employed as fitness functions, which combined radiuses of curvature, thicknesses among lens surfaces and refractive indices regarding an optical system. By using this function, the aberration correction is carried out. A design example using PSO is given. Results show that PSO as optical design tools is practical and powerful, and this method is no longer dependent on the lens initial structure and can arbitrarily create search ranges of structural parameters of a lens system, which is an important step towards automatic design with artificial intelligence.

  19. Comparison of choroidal thickness measurements between spectral-domain OCT and swept-source OCT in normal and diseased eyes.

    Science.gov (United States)

    Zafar, Sidra; Siddiqui, Ma Rehman; Shahzad, Rida

    2016-01-01

    Sub-foveal choroidal thickness (SFCT) is affected in many ocular diseases. The aim of this study was to compare SFCT measurements between Topcon 3D 2000 spectral-domain optical coherence tomography (SD-OCT) and Topcon swept-source OCT (SS-OCT), with different laser wavelengths, in normal and diseased populations. This was a prospective, cross-sectional, noninterventional study including 27 normal volunteers and 27 participants with retinal disease. OCT scans were performed sequentially and under standardized conditions using both SD-OCT and SS-OCT. The OCT scans were evaluated by two independent graders. Paired t -tests and intraclass correlation coefficients (ICCs) were used to assess the statistically significant difference between SFCT measurements as measured by the two devices. Mean SFCT measurements for all 54 participants were 264.9±103.1 μm using SD-OCT (range: 47-470 μm) and 278.5±110.5 μm using SS-OCT (range: 56-502 μm), with an inter-device ICC of 0.850. Greater variability was noted in the diseased eyes. Inter-device ICCs were 0.870 (95% CI; 0.760-0.924) and 0.840 (95% CI; 0.654-0.930) for normal and diseased eyes, respectively. However, the difference was not statistically significant ( P =0.132). Both machines reliably measure SFCT. Larger studies are needed to confirm these findings.

  20. On-Ice Arctic Sea Ice Thickness Measurements by Auger, Core, and Electromagnetic Induction, From the Fram Expedition Onward, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of in situ sea ice thickness measurements derived from drill holes, gauges, thermistor strings, and surface electromagnetic induction. From...

  1. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

  2. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  3. Effect of hemodialysis on intraocular lens power calculation.

    Science.gov (United States)

    Çalışkan, Sinan; Çelikay, Osman; Biçer, Tolga; Aylı, Mehmet Deniz; Gürdal, Canan

    2016-01-01

    To evaluate changes in ocular biometric parameters after hemodialysis (HD) in patients with end-stage renal disease (ESRD). Forty eyes of 40 patients undergoing HD were included in this cross-sectional study. Keratometry (K) readings, white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter, lens thickness (LT), axial length (AL), and intraocular lens (IOL) power calculation were measured with Lenstar LS 900 (Haag Streit AG, Koeniz, Switzerland) before and after hemodialysis. Intraocular pressure (IOP) was measured with a non-contact tonometer (Tonopachy NT-530P, Nidek Co., LTD, Tokyo, Japan). Main outcomes were changes in biometric parameters after HD. Reliability of the measurements (intraclass correlation coefficients (ICCs)) and the effect size (Cohen's d) were also calculated. Mean difference in AL before and after HD was -0.041 ± 0.022 mm with ICCs > 0.90 (p  0.90 (p = 0.041 and Cohen's d = 0.20). Hemodialysis had no significant effect on K readings, WTW distance, CCT, ACD, LT, or IOP. Axial length and pupil diameter increase after HD with small effect size, while HD does not significantly affect IOL power calculations.

  4. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo

    2010-01-01

    PURPOSE: To study the relation between ambient environmental ultraviolet radiation exposure and lens fluorescence. METHODS: Non-invasive lens fluorometry measurements were compared in healthy Bolivian and Danish subjects. Background ultraviolet radiation was 4.5 times higher in Bolivia than in De...... living at sea level at 55 degrees northern latitude. These results suggest that lens ageing, as assessed by lens autofluorometry, is independent of exposure to ultraviolet radiation....

  5. The application of β-ray excitation fluorescence to the measurement of the thickness of deposits and to analysis

    International Nuclear Information System (INIS)

    Martinelli, P.

    1961-01-01

    Principles of the method are first outlined and the instrumentation used is described. The different types of radiation detectors are subject of a detailed study. As a source of β-radiation 90 (Sr + Y) was used as well as 147 Pm. Great care was taken to eliminate back-diffused electrons by deflection by a strong permanent magnet. The method was applied to the measurement of the thickness of deposits of Cr, Zn, Sn, Cd and Cu on iron as well as Zn, Cr, Ag and Au on copper and the results obtained are discussed. An attempt was made, to use β-X-ray fluorescence for the analysis of minerals, iron ore and glass and for routine control of Si-Mn, Si-Ca, Fe-Mn and Fe-W. Finally the method of β-X-ray fluorescence is compared with normal-X-ray fluorescence and possibilities of further development are cited. (author) [fr

  6. Reusable bi-directional 3ω sensor to measure thermal conductivity of 100-μm thick biological tissues.

    Science.gov (United States)

    Lubner, Sean D; Choi, Jeunghwan; Wehmeyer, Geoff; Waag, Bastian; Mishra, Vivek; Natesan, Harishankar; Bischof, John C; Dames, Chris

    2015-01-01

    Accurate knowledge of the thermal conductivity (k) of biological tissues is important for cryopreservation, thermal ablation, and cryosurgery. Here, we adapt the 3ω method-widely used for rigid, inorganic solids-as a reusable sensor to measure k of soft biological samples two orders of magnitude thinner than conventional tissue characterization methods. Analytical and numerical studies quantify the error of the commonly used "boundary mismatch approximation" of the bi-directional 3ω geometry, confirm that the generalized slope method is exact in the low-frequency limit, and bound its error for finite frequencies. The bi-directional 3ω measurement device is validated using control experiments to within ±2% (liquid water, standard deviation) and ±5% (ice). Measurements of mouse liver cover a temperature ranging from -69 °C to +33 °C. The liver results are independent of sample thicknesses from 3 mm down to 100 μm and agree with available literature for non-mouse liver to within the measurement scatter.

  7. A Simplified Method to Measure Choroidal Thickness Using Adaptive Compensation in Enhanced Depth Imaging Optical Coherence Tomography

    Science.gov (United States)

    Gupta, Preeti; Sidhartha, Elizabeth; Girard, Michael J. A.; Mari, Jean Martial; Wong, Tien-Yin; Cheng, Ching-Yu

    2014-01-01

    Purpose To evaluate a simplified method to measure choroidal thickness (CT) using commercially available enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT). Methods We measured CT in 31 subjects without ocular diseases using Spectralis EDI SD-OCT. The choroid-scleral interface of the acquired images was first enhanced using a post-processing compensation algorithm. The enhanced images were then analysed using Photoshop. Two graders independently graded the images to assess inter-grader reliability. One grader re-graded the images after 2 weeks to determine intra-grader reliability. Statistical analysis was performed using intra-class correlation coefficient (ICC) and Bland-Altman plot analyses. Results Using adaptive compensation both the intra-grader reliability (ICC: 0.95 to 0.97) and inter-grader reliability (ICC: 0.93 to 0.97) were perfect for all five locations of CT. However, with the conventional technique of manual CT measurements using built-in callipers provided with the Heidelberg explorer software, the intra- (ICC: 0.87 to 0.94) and inter-grader reliability (ICC: 0.90 to 0.93) for all the measured locations is lower. Using adaptive compensation, the mean differences (95% limits of agreement) for intra- and inter-grader sub-foveal CT measurements were −1.3 (−3.33 to 30.8) µm and −1.2 (−36.6 to 34.2) µm, respectively. Conclusions The measurement of CT obtained from EDI SD-OCT using our simplified method was highly reliable and efficient. Our method is an easy and practical approach to improve the quality of choroidal images and the precision of CT measurement. PMID:24797674

  8. A simplified method to measure choroidal thickness using adaptive compensation in enhanced depth imaging optical coherence tomography.

    Directory of Open Access Journals (Sweden)

    Preeti Gupta

    Full Text Available PURPOSE: To evaluate a simplified method to measure choroidal thickness (CT using commercially available enhanced depth imaging (EDI spectral domain optical coherence tomography (SD-OCT. METHODS: We measured CT in 31 subjects without ocular diseases using Spectralis EDI SD-OCT. The choroid-scleral interface of the acquired images was first enhanced using a post-processing compensation algorithm. The enhanced images were then analysed using Photoshop. Two graders independently graded the images to assess inter-grader reliability. One grader re-graded the images after 2 weeks to determine intra-grader reliability. Statistical analysis was performed using intra-class correlation coefficient (ICC and Bland-Altman plot analyses. RESULTS: Using adaptive compensation both the intra-grader reliability (ICC: 0.95 to 0.97 and inter-grader reliability (ICC: 0.93 to 0.97 were perfect for all five locations of CT. However, with the conventional technique of manual CT measurements using built-in callipers provided with the Heidelberg explorer software, the intra- (ICC: 0.87 to 0.94 and inter-grader reliability (ICC: 0.90 to 0.93 for all the measured locations is lower. Using adaptive compensation, the mean differences (95% limits of agreement for intra- and inter-grader sub-foveal CT measurements were -1.3 (-3.33 to 30.8 µm and -1.2 (-36.6 to 34.2 µm, respectively. CONCLUSIONS: The measurement of CT obtained from EDI SD-OCT using our simplified method was highly reliable and efficient. Our method is an easy and practical approach to improve the quality of choroidal images and the precision of CT measurement.

  9. Discrepant Measurements of Maximal Left Ventricular Wall Thickness Between Cardiac Magnetic Resonance Imaging and Echocardiography in Patients With Hypertrophic Cardiomyopathy.

    Science.gov (United States)

    Hindieh, Waseem; Weissler-Snir, Adaya; Hammer, Helene; Adler, Arnon; Rakowski, Harry; Chan, Raymond H

    2017-08-01

    We sought to compare maximal left ventricular (LV) wall thickness (WT) measurements as obtained by routine clinical practice between echocardiography and cardiac magnetic resonance (CMR) and document causes of discrepancy. One-hundred and ninety-five patients with hypertrophic cardiomyopathy (median age, 52.8±15.1 years) who underwent echocardiography and CMR imaging within 6 months (median, 41 days; interquartile range, 16-97 days) were included. LVWT was assessed in parasternal long and short axis by 2-dimensional echocardiography and in short axis by CMR. By Bland-Altman plot, mean maximal LVWT difference between echocardiography and CMR was 0.5 mm (95% confidence interval, -6.9, 7.8) with equal distribution of discrepancy along the full range of LVWT. Ninety-seven patients (49.7%) were identified to have intermodal measurement discrepancies ≥10%. In 7 patients (7.2%), reported measurement by CMR was inaccurate because of interpretation error. In 90 patients (92.8%), echocardiography underestimated (n=32; 33.0%) or overestimated (n=58; 59.8%) maximal LVWT. Underestimation was because of focal LV hypertrophy (n=10; 10.3%) or poor acoustic windows (n=22; 22.7%) while overestimation resulted from inclusion of right ventricular myocardium (n=37; 38.1%), LV trabeculations (n=5; 5.2%), papillary muscle (n=3; 3.1%), and apical-septal bundle (n=1; 1.0%), as well as imaging plane obliquity (n=7; 12.5%). In 31 (15.9%) patients, measurement discrepancy occurred at diagnostic or prognostic cut-offs. Although maximal LVWT by echocardiography in general measured similar to CMR, discordance because of limitations in echocardiography technique was present in a significant subset of patients. As measurement of LVWT impacts diagnosis and sudden death management, CMR should be considered as part of routine evaluation of all patients with hypertrophic cardiomyopathy. © 2017 American Heart Association, Inc.

  10. Measurement of void swelling in thick non-uniformly irradiated 304 stainless steel blocks using nondestructive ultrasonic techniques

    International Nuclear Information System (INIS)

    Garner, F.A.; Okita, T.; Isobe, Y.; Etoh, J.; Sagisaka, M.; Matsunaga, T.; Freyer, P.D.; Huang, Y.; Wiezorek, J.M.K.; Porter, D.L.

    2015-01-01

    Void swelling is of potential importance in PWR austenitic internals, especially in components that will see higher doses during plant lives beyond 40 years. Proactive surveillance of void swelling is required to identify its emergence before swelling reaches levels that cause high levels of embrittlement and distortion. Non-destructive measurements of ultrasonic velocity can measure swelling at fractions of a percent. To demonstrate the feasibility of this technique for PWR application we have investigated five blocks of 304 stainless steel that were irradiated in the EBR-II fast reactor. These blocks were of hexagonal cross-section, with thickness of about 50 mm and lengths of about 218-245 mm. They were subjected to significant axial and radial gradients in gamma heating, temperature and dpa rate, producing complex internal distributions of swelling, reaching about 3.5% maximum at an off-center mid-core position. Swelling decreases both the density and the elastic moduli, thereby impacting the ultrasonic velocity. Concurrently, carbide precipitates form, producing increases in density and decreases in elastic moduli. Using blocks from both low and high dpa levels it was possible to separate the ultrasonic contributions of voids and carbides. Time-of-flight ultrasonic measurements were used to non-destructively measure the internal distribution of void swelling. These distributions were confirmed using non-destructive profilometry followed by destructive cutting to provide density change and electron microscopy data. It was demonstrated that the four measurement types produce remarkably consistent results. Therefore ultrasonic measurements offer great promise for in-situ surveillance of voids in PWR core internals. (authors)

  11. Ultrasonic Measurement of Common Carotid Intima-Media Thickness in Type 2 Diabetic and Non-Diabetic Patients

    International Nuclear Information System (INIS)

    Alizadeh, Ahmad; Roudbari, Ali; Heidarzadeh, Abtin; Babaei Jandaghi, Ali; Bani Jamali, Maryam

    2012-01-01

    Diabetes mellitus is a widespread disease. Its vascular complications can be characterized by arteriosclerosis formation in carotid arteries. Due to its delayed diagnosis resulting in more complications in Iran, it seems that screening diabetic patients is mandatory. The aim of this study was to compare the intima-media thickness (IMT) of carotid artery in diabetic and non-diabetic patients. This is a cross-sectional study, which included 80 participants (40 diabetics and 40 non-diabetics). By using ultrasound, bilateral IMTs of the distal carotid were measured and the data were analyzed using ANOVA and multivariate regression tests in SPSS 14. The mean IMT was 0.97 in diabetic patients and 0.63 in non-diabetics (P < 0.001). Age and gender had significant positive effects on the increase of IMT (P < 0.05 and P < 0.005, respectively for age and gender). Past medical history of coronary heart disease (CHD) and cerebrovascular accident (CVA) in diabetes is associated significantly with an increase in IMT (P =0.019 and 0.027 respectively). Other confounding variables such as smoking, history of hypertension (HTN) and hyperlipoproteinemia (HLP) in diabetic patients showed no significant relationship with the increase of IMT. Although measuring the IMT of the carotid artery by sonography is a useful tool for screening diabetic patients, more studies are needed for determining how to use these measurements in promoting the patients outcomes

  12. Pulsed ultrasonic comb filtering effect and its applications in the measurement of sound velocity and thickness of thin plates.

    Science.gov (United States)

    Liu, Jingfei; Declercq, Nico F

    2017-03-01

    An analytical and experimental study of the pulsed ultrasonic comb filtering effect is presented in this work intending to provide a fundamental tool for data analysis and phenomenon understanding in pulsed ultrasonics. The basic types of comb filter, feedforward and feedback filters, are numerically simulated and demonstrated. The characteristic features of comb filters, which include the formula for determining the locations of the spectral peaks or notches and the relationship between its temporal characteristics (relative time delay between constituent pulses) and its spectral characteristics (frequency interval between peaks or notches), are theoretically derived. To demonstrate the applicability of the comb filtering effect, it is applied to measuring the sound velocities and thickness of a thin plate sample. It is proven that the comb filtering effect based method not only is capable of accurate measurements, but also has advantages over the conventional time-of-flight based method in thin plate measurements. Furthermore, the principles developed in this study have potential applications in any pulsed ultrasonic cases where the output signal shows comb filter features. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Pulsed TV holography measurement and digital reconstruction of compression acoustic wave fields: application to nondestructive testing of thick metallic samples

    International Nuclear Information System (INIS)

    Trillo, C; Doval, A F; Deán-Ben, X L; López-Vázquez, J C; Fernández, J L; Hernández-Montes, S

    2011-01-01

    This paper describes a technique that numerically reconstructs the complex acoustic amplitude (i.e. the acoustic amplitude and phase) of a compression acoustic wave in the interior volume of a specimen from a set of full-field optical measurements of the instantaneous displacement of the surface. The volume of a thick specimen is probed in transmission mode by short bursts of narrowband compression acoustic waves generated at one of its faces. The temporal evolution of the displacement field induced by the bursts emerging at the opposite surface is measured by pulsed digital holographic interferometry (pulsed TV holography). A spatio-temporal 3D Fourier transform processing of the measured data yields the complex acoustic amplitude at the plane of the surface as a sequence of 2D complex-valued maps. Finally, a numerical implementation of the Rayleigh–Sommerfeld diffraction formula is employed to reconstruct the complex acoustic amplitude at other planes in the interior volume of the specimen. The whole procedure can be regarded as a combination of optical digital holography and acoustical holography methods. The technique was successfully tested on aluminium specimens with and without an internal artificial defect and sample results are presented. In particular, information about the shape and position of the defect was retrieved in the experiment performed on the flawed specimen, which indicates the potential applicability of the technique for the nondestructive testing of materials

  14. An improved approach for accurate and efficient measurement of common carotid artery intima-media thickness in ultrasound images.

    Science.gov (United States)

    Li, Qiang; Zhang, Wei; Guan, Xin; Bai, Yu; Jia, Jing

    2014-01-01

    The intima-media thickness (IMT) of common carotid artery (CCA) can serve as an important indicator for the assessment of cardiovascular diseases (CVDs). In this paper an improved approach for automatic IMT measurement with low complexity and high accuracy is presented. 100 ultrasound images from 100 patients were tested with the proposed approach. The ground truth (GT) of the IMT was manually measured for six times and averaged, while the automatic segmented (AS) IMT was computed by the algorithm proposed in this paper. The mean difference±standard deviation between AS and GT IMT is 0.0231±0.0348 mm, and the correlation coefficient between them is 0.9629. The computational time is 0.3223 s per image with MATLAB under Windows XP on an Intel Core 2 Duo CPU E7500 @2.93 GHz. The proposed algorithm has the potential to achieve real-time measurement under Visual Studio.

  15. An Improved Approach for Accurate and Efficient Measurement of Common Carotid Artery Intima-Media Thickness in Ultrasound Images

    Directory of Open Access Journals (Sweden)

    Qiang Li

    2014-01-01

    Full Text Available The intima-media thickness (IMT of common carotid artery (CCA can serve as an important indicator for the assessment of cardiovascular diseases (CVDs. In this paper an improved approach for automatic IMT measurement with low complexity and high accuracy is presented. 100 ultrasound images from 100 patients were tested with the proposed approach. The ground truth (GT of the IMT was manually measured for six times and averaged, while the automatic segmented (AS IMT was computed by the algorithm proposed in this paper. The mean difference ± standard deviation between AS and GT IMT is 0.0231 ± 0.0348 mm, and the correlation coefficient between them is 0.9629. The computational time is 0.3223 s per image with MATLAB under Windows XP on an Intel Core 2 Duo CPU E7500 @2.93 GHz. The proposed algorithm has the potential to achieve real-time measurement under Visual Studio.

  16. Corrected electrostatic lens systems for ion beams

    International Nuclear Information System (INIS)

    Dalgish, R.L.

    1981-01-01

    Recent work in our laboratory has introduced a new class of electrostatic focus forming element for beams, the ELCO lens. It compares favourably with the electrostatic and magnetic quadrupole elements conventionally used for microbeam formation. The ELCO lens does however have disadvantages associated with apertures and alignment. We have continued with the development of ion beam lenses and have evolved a further class of lens element which eliminates aperture and alignment problems. This new element can be combined like optical lenses into an aberration corrected system. Experimental measurement on the basic lens element has confirmed mathematical analysis of ion trajectories through the element. This mathematical analysis predicts that the basic element can be combined into a corrected lens system for, either: (1) high resolution microprobe formation with intrinsic rastering ability, the spot size limited only by the beam properties; or (2) high quality image formation with large magnification/demagnification ratio and wide angular aperture. (orig.)

  17. Influence of age-related macular degeneration on macular thickness measurement made with fourier-domain optical coherence tomography.

    Science.gov (United States)

    Garas, Anita; Papp, András; Holló, Gábor

    2013-03-01

    To evaluate the influence of age-related macular degeneration (AMD) on macular thickness measurement made with Fourier-domain optical coherence tomography (RTVue-OCT) to detect glaucoma. : One nonglaucomatous eye of 79 white persons was imaged. This comprised 25 healthy eyes, 19 eyes with early/intermediate AMD (geographic atrophy excluded), 16 eyes with subfoveal choroidal neovascularization (CNV), and 19 CNV eyes after intravitreal antiangiogenic treatment [CNV-antivascular endothelial growth factor (VEGF)]. Compared with the age-matched controls, no difference in any nerve fiber layer and optic disc parameter was seen for any AMD group. No macular retinal segmentation error was detected in the control group. Localized inner retinal image segmentation errors topographically related to AMD were detected in 8 eyes with drusen (42.1%), all 16 CNV eyes (100%) and 17 eyes in the CNV-anti-VEGF group (89.5%; χ test, P0.05). In contrast, all pattern-based ganglion cell complex (GCC) parameters were significantly higher (more abnormal) in the CNV and CNV-anti-VEGF group than in the control eyes (Mann-Whitney test, Bonferroni correction, P<0.001). For GCC focal loss volume, the only pattern-based parameter classified by the software, the frequency of "borderline" and "outside normal limits" classifications was significantly greater in each AMD group than in the control group (χ test, Bonferroni correction, P ≤0.03). In nonglaucomatous eyes, AMD significantly influences the pattern-based inner macular thickness parameters of the RTVue optical coherence tomograph and the software-provided classification of GCC focal loss volume, for detection of glaucoma.

  18. Diagnostic ability of retinal nerve fiber layer thickness measurements and neurologic hemifield test to detect chiasmal compression.

    Science.gov (United States)

    Moon, Chan Hee; Lee, Si Hyung; Kim, Bum-Tae; Hwang, Sun Chul; Ohn, Young-Hoon; Park, Tae Kwann

    2012-08-09

    The purpose of the study was to investigate the diagnostic ability of the neurologic hemifield test (NHT) and retinal nerve fiber layer (RNFL) thickness measurements to detect chiasmal compression. Thirty-seven patients with chiasmal compression, 35 patients with glaucoma, and 30 patients with glaucoma suspect were enrolled. The NHT score was established from a 30-2 visual field pattern deviation probability plot. Each test point value was calculated for a number that was inversely proportional to its pattern deviation probability. The NHT score was the absolute value of the difference in the sum of the point scores for two symmetrical regions of 16 points on either side of the vertical meridian. RNFL thickness was scored from 0 to 10 according to the pattern of RNFL loss and probability of abnormality. Solely present nasal or temporal RNFL defects were scored high, and exclusively appearing superior or nasal RNFL defects were scored low. The differences in the NHT and RNFL scores among the three groups were compared. Diagnostic ability was assessed by receiver operating characteristic (ROC) analysis. The NHT and RNFL scores were significantly higher in patients with chiasmal compression than in patients with glaucoma and glaucoma suspect. The area under the ROC curve (AROC) was 0.734 of the NHT score and 0.613 of the RNFL score. When AROC was calculated using the NHT and RNFL scores concurrently, AROC was increased to 0.807. The NHT score and RNFL score have diagnostic ability to detect chiasmal compression, and simultaneous assessment of NHT and RNFL scores improves the diagnostic power.

  19. Do epidermal lens cells facilitate the absorptance of diffuse light?

    Science.gov (United States)

    Brodersen, Craig R; Vogelmann, Thomas C

    2007-07-01

    Many understory plants rely on diffuse light for photosynthesis because direct light is usually scattered by upper canopy layers before it strikes the forest floor. There is a considerable gap in the literature concerning the interaction of direct and diffuse light with leaves. Some understory plants have well-developed lens-shaped epidermal cells, which have long been thought to increase the absorption of diffuse light. To assess the role of epidermal cell shape in capturing direct vs. diffuse light, we measured leaf reflectance and transmittance with an integrating sphere system using leaves with flat (Begonia erythrophylla, Citrus reticulata, and Ficus benjamina) and lens-shaped epidermal cells (B. bowerae, Colocasia esculenta, and Impatiens velvetea). In all species examined, more light was absorbed when leaves were irradiated with direct as opposed to diffuse light. When leaves were irradiated with diffuse light, more light was transmitted and more was reflected in both leaf types, resulting in absorptance values 2-3% lower than in leaves irradiated with direct light. These data suggest that lens-shaped epidermal cells do not aid the capture of diffuse light. Palisade and mesophyll cell anatomy and leaf thickness appear to have more influence in the capture and absorption of light than does epidermal cell shape.

  20. Variation of clearance considering viscosity of the solution used in the reservoir and following scleral lens wear over time.

    Science.gov (United States)

    Courey, Claudine; Michaud, Langis

    2017-08-01

    This study aims to evaluate the settling of a scleral lens and if this process is influenced by the nature of the fluid layer. A prospective, non-randomized control study was performed using an 18mm scleral lens. They were fitted with a central clearance of 400 um at insertion. One eye was randomly assigned to be fitted with a non-preserved gel solution of carboxymethylcellulose, while the other was inserted with non-preserved saline. Measurements of clearance in 3 locations were taken (OCT) at baseline, every 30min up to 1h30 post insertion and every 2h thereafter up to 6h00 of wear. A two-way repeated measure analysis of variance (liquids×times) was used to test central, nasal and temporal fluid thickness. Following 6h of wear, the 18mm lens had a mean central settling of 70.0±9.8μm, 36.7±9.8μm of which occurred within the first 30min of wear. There was no significant difference between lenses filled with non-preserved saline to those with non-preserved gel. However, a paired comparison concluded to a significant difference between mean nasal settling (41.4μm) and temporal settling (20.4μm). With respect to the lens studied, current results suggest that practitioners can evaluate the lens 30min post insertion and can estimate the amount of fluid that will remain after lens stabilization by doubling the value obtained initially. The use of non-preserved saline or non-preserved more viscous solution to fill the lens does not influence its settling. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  1. Accuracy of intraocular lens power calculation using three optical biometry measurement devices: the OA-2000, Lenstar-LS900 and IOLMaster-500.

    Science.gov (United States)

    Reitblat, Olga; Levy, Adi; Kleinmann, Guy; Assia, Ehud I

    2018-03-12

    To compare ocular measurements of three optical biometry devices and their application in intraocular lens (IOL) power calculations. One hundred and forty eyes which had undergone cataract extraction surgery with preoperative biometry with OA--2000, IOLMaster-500, and Lenstar-LS900 were enrolled. Biometry measurements of the three devices were compared. The deviation of the postoperative refraction from the preoperative refractive target was calculated with different formulas (Barrett Universal II, Hoffer Q, Holladay I, and SRK/T). Errors in the predicted astigmatism using the Barrett toric calculator were calculated for the toric IOLs. Additional 6465 eyes in which the IOLMaster-500 failed to measure axial length (AL) were reviewed. The percentage of successful measurements using the OA-2000 in those eyes was calculated. High agreement was found between the three devices for AL, anterior chamber depth, and average keratometry measurements (interclass correlation confidents: 1.000, 0.970, and 0.998, respectively, P 2000 yielded a lower against-the-rule (ATR) centroid error in the predicted astigmatism than the IOLMaster-500 and Lenstar-LS900 (0.06 D ± 0.59 at 13.4° vs. 0.20 D ± 0.61 at 14.8° and 0.16 D ± 0.55 at 21.4°, respectively, P 2000 had 284 (94.35%) successful measurements. The OA-2000 measurements showed good agreement with those of the IOLMaster-500 and Lenstar-LS900. Our results may suggest a potential advantage of the OA-2000 device in toric IOLs calculations and AL measurement success rate.

  2. Comparison of choroidal thickness measurements between spectral-domain OCT and swept-source OCT in normal and diseased eyes

    Directory of Open Access Journals (Sweden)

    Zafar S

    2016-11-01

    Full Text Available Sidra Zafar,1 MA Rehman Siddiqui,2,3 Rida Shahzad1 1Medical College, Aga Khan University Hospital, 2Department of Ophthalmology, Shahzad Eye Hospital, 3South City Hospital, Karachi, Pakistan Purpose: Sub-foveal choroidal thickness (SFCT is affected in many ocular diseases. The aim of this study was to compare SFCT measurements between Topcon 3D 2000 spectral-domain optical coherence tomography (SD-OCT and Topcon swept-source OCT (SS-OCT, with different laser wavelengths, in normal and diseased populations. Materials and methods: This was a prospective, cross-sectional, noninterventional study including 27 normal volunteers and 27 participants with retinal disease. OCT scans were performed sequentially and under standardized conditions using both SD-OCT and SS-OCT. The OCT scans were evaluated by two independent graders. Paired t-tests and intraclass correlation coefficients (ICCs were used to assess the statistically significant difference between SFCT measurements as measured by the two devices. Results: Mean SFCT measurements for all 54 participants were 264.9±103.1 µm using SD-OCT (range: 47–470 µm and 278.5±110.5 µm using SS-OCT (range: 56–502 µm, with an inter-device ICC of 0.850. Greater variability was noted in the diseased eyes. Inter-device ICCs were 0.870 (95% CI; 0.760–0.924 and 0.840 (95% CI; 0.654–0.930 for normal and diseased eyes, respectively. However, the difference was not statistically significant (P=0.132. Conclusion: Both machines reliably measure SFCT. Larger studies are needed to confirm these findings. Keywords: choroidal imaging, diseased, normal, SD-OCT, SS-OCT

  3. Quantitative measurement of mean inner potential and specimen thickness from high-resolution off-axis electron holograms of ultra-thin layered WSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Florian, E-mail: f.winkler@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Tavabi, Amir H. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Barthel, Juri [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Gemeinschaftslabor für Elektronenmikroskopie (GFE), RWTH Aachen University, D-52074 Aachen (Germany); Duchamp, Martial [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Yucelen, Emrah [FEI Company, Achtseweg Noord 5, Eindhoven 5600 KA (Netherlands); Borghardt, Sven; Kardynal, Beata E. [Peter Grünberg Institute 9 (PGI-9), Forschungszentrum Jülich, D-52425 Jülich (Germany); and others

    2017-07-15

    The phase and amplitude of the electron wavefunction that has passed through ultra-thin flakes of WSe{sub 2} is measured from high-resolution off-axis electron holograms. Both the experimental measurements and corresponding computer simulations are used to show that, as a result of dynamical diffraction, the spatially averaged phase does not increase linearly with specimen thickness close to an [001] zone axis orientation even when the specimen has a thickness of only a few layers. It is then not possible to infer the local specimen thickness of the WSe{sub 2} from either the phase or the amplitude alone. Instead, we show that the combined analysis of phase and amplitude from experimental measurements and simulations allows an accurate determination of the local specimen thickness. The relationship between phase and projected potential is shown to be approximately linear for extremely thin specimens that are tilted by several degrees in certain directions from the [001] zone axis. A knowledge of the specimen thickness then allows the electrostatic potential to be determined from the measured phase. By using this combined approach, we determine a value for the mean inner potential of WSe{sub 2} of 18.9±0.8 V, which is 12% lower than the value calculated from neutral atom scattering factors. - Highlights: • Quantitative analysis of high resolution electron holograms of WSe{sub 2}. • Local specimen thickness determination and estimation of tilt angle. • Mean inner potential evaluation of WSe2 avoiding dynamical diffraction.

  4. Surface-sensitive FTIR spectral measurements of nanogram samples using 30-100-μm-thick planar Ge waveguides

    Science.gov (United States)

    Braiman, Mark S.; Plunkett, Susan E.; Stone, James J.

    1998-06-01

    We have developed techniques for fabricating supported planar Ge waveguides that are useful for measuring broadband mid-IR evanescent-wave absorption spectra from small numbers of molecules. The waveguides are ground and polished as thin as 30 μm, starting from larger pieces of commercially-available single-crystal Ge. Such waveguides are useful as extremely sensitive multiple-internal-reflection elements, when used in conjunction with an FTIR spectrometer with microscope accessory and a small-area detector. With careful polishing and alignment, optical losses can be reduced to those predicted as resulting from ray spreading within the waveguide and from reflection at the air-Ge interface. For example, by using a Spectra-Tech Research IR-Plan™ microscope with a (100 μm)2 detector element, we have been able to demonstrate broadband IR power transmission through a 30-μm-thick, 3-mm-wide waveguide that is 4% of the open-beam throughput focused through a 30 μm×3 mm slit at the sample focal plane. Supported planar Ge waveguides between 30 and 100 μm in thickness function as internal reflection elements with 10-20 reflections per mm of length. Using such waveguides, we have been able to make surface-sensitive spectral measurements of tiny samples. For example, we can easily observe the FTIR absorption spectrum selectively from the adhesive layer on 3M Scotch™ tape, without interfering absorption from the tape backing. A 0.07 mm2 piece of tape, carrying only several μg of adhesive, still produces distinct bands with absorbance values as large as 0.18. The great sensitivity to monolayer samples covering small contact areas has allowed us to measure useful FTIR spectra of the plasma membranes of intact cells, e.g. individual 1-mm-diameter frog oocytes, submerged in aqueous media. The protein and lipid components in a patch of such a single-bilayer membrane give absorbances on the order of 0.01.

  5. Inferred pressure gradient and fluid flow in a condensing sessile droplet based on the measured thickness profile

    Science.gov (United States)

    Gokhale, Shripad J.; Plawsky, Joel L.; Wayner, Peter C.; DasGupta, Sunando

    2004-06-01

    The thickness and curvature profiles of partially wetting condensing drops of 2-propanol on a quartz surface were measured using image analyzing interferometry and a new data analysis procedure. The profiles give fundamental insight into the phenomena of phase change, pressure gradient, fluid flow and spreading in a condensing drop, and the physics of interfacial phenomena in the contact line region of a polar fluid. The precursor adsorbed film and interfacial slope (a measure of the contact angle) and curvature profiles are consistent with previous concepts based on interfacial models. The curvature profiles, which were obtained using a new data reduction procedure, clearly demonstrate the convex nature of the drop near the thicker part (negative value of curvature), whereas, in the thinner region, the drop is concave (positive curvature) where the partially wetting liquid merges with a flat adsorbed film. The pressure profiles inside the drop are calculated from the augmented Young-Laplace equation showing that the pressure gradient increases with an increase in the spreading velocity (rates of condensation) to support the higher liquid flow rates associated with the growth of the drop. Internal flow is towards the point of maximum positive curvature from both the thin film and convex regions. Apolar and polar components of the spreading coefficient help describe the interfacial phenomena occurring. The experimental techniques are relatively simple but very revealing.

  6. Impact of errors in recorded compressed breast thickness measurements on volumetric density classification using volpara v1.5.0 software

    OpenAIRE

    Waade, G; Highnam, R; Hauge, I; McEntee, M; Hofvind, S; Denton, E; Kelly, J; Sarwar, J; Hogg, P

    2016-01-01

    Purpose: Mammographic density has been demonstrated to predict breast cancer risk. It has been proposed that it could be used for stratifying screening pathways and recommending additional imaging. Volumetric density tools use the recorded compressed breast thickness (CBT) of the breast measured at the x-ray unit in their calculation, however the accuracy of the recorded thickness can vary. The aim of this study was to investigate whether inaccuracies in recorded CBT impact upon volumetric de...

  7. [The Effect of Cataract Surgery on the Reproducibility and Outcome of Optical Coherence Tomography Measurements of Macular and Retinal nerve Fibre Layer Thickness].

    Science.gov (United States)

    Pašová, P; Skorkovská, K

    2016-01-01

    Optical coherence tomography (OCT) is a non-invasive imaging technique used for the examination of the macula and peripapillary retinal nerve fibre layer (RNFL), the result of which may be affected by the quality of the scanned image. The aim of our study was to assess the influence of uncomplicated cataract extraction on the measurement of macular and RNFL thickness with OCT and to determine the reproducibility of this method before and after cataract surgery in a group of healthy people. We also evaluated the effect of different intraocular lenses (IOL) (with/without yellow filter) on the reproducibility of the OCT examination. The study group included 51 eyes of 51 patients who underwent cataract surgery with posterior chamber IOL implantation. Macular and RNFL thickness were measured with spectral domain OCT (Optovue, Model RT 100) one week before surgery, and postoperatively after one and six months. Three OCT scans were performed at each visit to assess the reproducibility of the measurement. Data were statistically processed. Analysis of the changes in macular and RNFL thickness showed a significant increase in retinal thickness, with the maximum increase one month after surgery, and regression of this thickening six months after surgery. Reproducibility of OCT examination improved significantly after cataract surgery, even though the preoperative values were of low coefficient of variance and therefore of high accuracy. No difference was found in the use of different intraocular lenses on the reproducibility of the OCT examination. The presence of cataract affects the OCT measurement of macular and RNFL thickness. The reproducibility of the method significantly improves after cataract surgery. It is likely that the increase in macular and RNFL thickness after cataract removal is partly due to improvement in the quality of the scanned image and thus to the greater accuracy of the OCT examination. optical coherence tomography, glaucoma, cataract, macular

  8. Measurement of muscle thickness of the serratus anterior and lower trapezius using ultrasound imaging in competitive recreational adult swimmers, with and without current shoulder pain.

    Science.gov (United States)

    McKenna, Leanda J; de Ronde, Mandy; Le, Minyang; Burke, William; Graves, Anna; Williams, Sian A

    2018-02-01

    To compare serratus anterior and lower trapezius muscle thickness between swimmers with and without current shoulder pain, and between sides when measured by real-time ultrasound imaging. A single blinded age and gender-matched case-control study with 26 symptomatic and 26 asymptomatic recreational swimmers. Muscle thickness of serratus anterior and lower trapezius were measured using previously validated real-time ultrasound imaging protocols. Serratus anterior thickness was measured in side lying with 90° of glenohumeral flexion at rest and during a scapular protraction contraction. Lower trapezius thickness was measured in prone with 145° of glenohumeral abduction whilst at rest and when holding the weight of the arm. There was no statistically significant difference between the muscle thickness of serratus anterior and lower trapezius between the symptomatic shoulder and the dominance-matched shoulder in the asymptomatic group of swimmers. There was also no significant difference in muscle thickness between the symptomatic side and asymptomatic side within the symptomatic group. There appears to be no difference in serratus anterior and lower trapezius thickness between swimmers who have mild to moderate shoulder pain, who continue to swim and those who do not have shoulder pain. When imaging the serratus anterior and lower trapezius in swimmers with mild shoulder pain, clinicians should expect no differences between sides. If muscle thickness differences between sides are detected in recreational swimmers, this may indicate that the swimmer is participating in other asymmetrical activities or has a higher level of shoulder pain. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  9. Reproducibility of aortic intima-media thickness in infants using edge-detection software and manual caliper measurements.

    Science.gov (United States)

    McCloskey, Kate; Ponsonby, Anne-Louise; Carlin, John B; Jachno, Kim; Cheung, Michael; Skilton, Michael R; Koleff, Jane; Vuillermin, Peter; Burgner, David

    2014-06-03

    Aortic intima-media thickness measured by transabdominal ultrasound (aIMT) is an intermediate phenotype of cardiovascular risk. We aimed to (1) investigate the reproducibility of aIMT in a population-derived cohort of infants; (2) establish the distribution of aIMT in early infancy; (3) compare measurement by edge-detection software to that by manual sonographic calipers; and (4) assess the effect of individual and environmental variables on image quality. Participants were term infants recruited to a population-derived birth cohort study. Transabdominal ultrasound was performed at six weeks of age by one of two trained operators. Thirty participants had ultrasounds performed by both operators on the same day. Data were collected on environmental (infant sleeping, presence of a sibling, use of sucrose, timing during study visit) and individual (post-conception age, weight, gender) variables. Two readers assessed image quality and measured aIMT by edge-detection software and a subset by manual sonographic calipers. Measurements were repeated by the same reader and between readers to obtain intra-observer and inter-observer reliability. Aortic IMT was measured successfully using edge-detection in 814 infants, and 290 of these infants also had aIMT measured using manual sonographic calipers. The intra-reader intra-class correlation (ICC) (n = 20) was 0.90 (95% CI 0.76, 0.96), mean difference 1.5 μm (95% LOA -39, 59). The between reader ICC using edge-detection (n = 20) was 0.92 (95% CI 0.82, 0.97) mean difference 2 μm (95% LOA -45.0, 49.0) and with manual caliper measurement (n = 290) the ICC was 0.84 (95% CI 0.80, 0.87) mean difference 5 μm (95% LOA -51.8, 61.8). Edge-detection measurements were greater than those from manual sonographic calipers (mean aIMT 618 μm (50) versus mean aIMT 563 μm (49) respectively; p calipers. Image quality is not substantially affected by individual and environmental factors.

  10. Use of high-resolution ultrasound to measure changes in plantar fascia thickness resulting from tissue creep in runners and walkers.

    Science.gov (United States)

    Welk, Aaron B; Haun, Daniel W; Clark, Thomas B; Kettner, Norman W

    2015-01-01

    This study sought to use high-resolution ultrasound to measure changes in plantar fascia thickness as a result of tissue creep generated by walking and running. Independent samples of participants were obtained. Thirty-six walkers and 25 runners walked on a treadmill for 10 minutes or ran for 30 minutes, respectively. Standardized measures of the thickness of the plantar fascia were obtained in both groups using high-resolution ultrasound. The mean thickness of the plantar fascia was measured immediately before and after participation. The mean plantar fascia thickness was decreased by 0.06 ± 0.33 mm SD after running and 0.03 ± 0.22 mm SD after walking. The difference between groups was not significant. Although the parameters of this study did not produce significant changes in the plantar fascia thickness, a slightly higher change in the mean thickness of the plantar fascia in the running group deserves further investigation. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  11. Daily Wear Contact Lenses Manufactured in Etafilcon A Are Noninferior to Two Silicone Hydrogel Lens Types With Respect to Hypoxic Stress.

    Science.gov (United States)

    Szczotka-Flynn, Loretta B; Debanne, Sara; Benetz, Beth Ann; Wilson, Tawnya; Brennan, Noel

    2016-10-20

    This study hypothesized that a traditional high-water contact lens of moderate oxygen transmissibility (Dk/t) is noninferior to common silicone hydrogel (SH) lenses worn for daily wear with respect to measures of hypoxic stress. Thirty-six habitual contact lens wearers completed wear of three lens types worn in a randomized order: etafilcon A (ACUVUE 2, control), lotrafilcon B (Air Optix Aqua), and comfilcon A (Biofinity). Central corneal thickness (CT) and limbal hyperemia were measured >2 hr after waking and after 6 to 8 hr of wear on days 1 and 7. Endothelial bleb formation was measured on day 1 of each lens type. Noninferiority of etafilcon A, with respect to the other two lens types, was assumed if the following difference margins of equivalence were met: types. Limbal hyperemia and endothelial bleb formation with all lenses were negligible, and noninferiority assumptions were met between the lens types for all outcomes. Equivalence of etafilcon A with respect to the two SH lenses for three measures of hypoxic stress was demonstrated.

  12. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N. N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  13. Contact lens in keratoconus

    OpenAIRE

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the En...

  14. Comparison of Visual, Refractive and Aberration Measurements of INTACS versus Toric ICL Lens Implantation; A Four-year Follow-up.

    Science.gov (United States)

    Ramin, Shahrokh; Sangin Abadi, Azad; Doroodgar, Farideh; Esmaeili, Mehrdad; Niazi, Faizollah; Niazi, Sana; Alinia, Cyrus; Golestani, Yaser; Taj Abadi, Reza

    2018-01-01

    This study was performed to evaluate the visual, refractive, and aberration measurement results of 2 implants, including Intacs Intracorneal Ring Segments (ICRS) and phakic Toric Implantable Collamer Lens (TICL), in patients with moderate Keratoconus (KCN). In this retrospective cross-sectional study, 30 patients with KCN with a mean age of 29.83 years were included in 2 groups, including the Intacs Intracorneal Ring Segments (ICRS) group and the phakic Toric Implantable Collamer Lens (TICL) group. Preoperative data as well as 6-month, 1-, 2-, 3- and 4-year follow-up data after the operation were collected and analyzed with the SPSS software (ver. 23.0, SPSS, Inc., Chicago, IL), using the paired t-test, independent t-test, repeated measures Analysis of Variance (ANOVA), and one-way ANOVA. This study included 30 patients with KCN with a mean age of 29.83 years and range of 25 to 35 years, including 17 males with a mean age of 30.11 years and 13 female with a mean age of 29.25 years. Except for preoperative Uncorrected Distance Visual Acuity (UCDVA), Spherical Equivalent (SE) and astigmatism, there was a significant difference between the 2 groups regarding other variables. The TICL group had a significantly better UCDVA and Best Corrected Distance Visual Acuity (BCDVA) in all post-operative follow-ups, and SE and astigmatism values were significantly lower in all post-operative follow-ups when compared with the ICRS group. There was a significant reduction in corneal and total coma as well as internal trefoil aberrations (P<0.01, P<0.01, and P=0.014, respectively) in the ICRS group, and TICL led to a significant reduction in internal trefoil aberration with P<0.03. Comparison of the 2 groups revealed a significant difference in corneal spherical (P<0.01) and total coma (P=0.02) aberrations and no significant differences in other HOA. Both ICRS and TICL are useful in patients with moderate KCN. However, TICL appears to have more stable and predictable vision results.

  15. Preoperative assessment of mesorectal fascial involvement in patients with rectal cancer: the diagnostic value of MDCT for measuring the mesorectal fascial thickness

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Min Jeong; Yoon, Jung Hee; Lee, Eun Joo; Cha, Seong Sook; Han, Sang Suk [College of Medicine, Inje University, Busan Paik Hopital, Busan (Korea, Republic of)

    2007-10-15

    To assess the diagnostic value of the use of multi-detector row computed tomography (MDCT) in evaluating mesorectal fascial (MRF) involvement in patients with T3 stage rectal cancer. From September 2005 to June 2006, we enrolled 21 patients with T3 stage rectal cancer. In addition, 21 healthy patients were enrolled in a control group. Two radiologists measured the mean MRF thickness independently. We considered positive MRF involvement when the MRF thickness exceeded 4 mm, and then we measured the MRF thickness of patients with T3 rectal cancer. We analyzed interobserver agreement for the measured MRF thickness of the control group and assessed the diagnostic value of 4 mm, 5 mm and 6 mm as references in predicting MRF involvement. The mean MRF thickness of the control group was 3.24 {+-} 0.50 mm (radiologist 1) and 3.04 {+-} 0.51 mm (radiologist 2). Using 4 mm, 5 mm and 6 mm as a reference thickness in predicting MRF involvement, sensitivity was 100%, 100% and 28.57%, specificity was 71.43%, 85.71% and 92.86%, the false negative rate (FNR) was 0%, 0% and 71.43%, the false positive rate (FPR) was 28.57%, 14.29% and 7.14%, the negative predictive value (NPV) was 100%, 100% and 72.2%, the positive predictive value (PPV) was 63.64%, 77.78% and 66.7%, and the accuracy was 80.95%, 90.48% and 71.43%. Preoperative assessment of the MRF thickness on MDCT is beneficial in predicting MRF involvement in patients with advanced rectal cancer and a value of 5 mm as a reference MRF thickness was established.

  16. Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

    Science.gov (United States)

    Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

    2013-11-01

    To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  17. Changes in abdominal muscle thickness measured by ultrasound are not associated with recovery in athletes with longstanding groin pain associated with resisted hip adduction.

    Science.gov (United States)

    Jansen, J A C G; Mens, J M A; Backx, Frank J G; Stam, Henk J

    2009-10-01

    Longitudinal single-cohort study. Athletes with longstanding groin pain associated with resisted hip adduction have been shown to have abnormal activation of the transversus abdominis (TA). Therefore, exercises targeting the TA to help stabilize the lumbopelvic area are generally used in the rehabilitation of these athletes. To investigate if (1) changes in abdominal muscle resting thickness and changes in relative thickness during lower extremity tasks after 14 weeks of intervention are related to changes in clinical status and (2) the changes in abdominal muscle resting/relative thickness are significant postintervention. In 21 athletes with longstanding groin pain associated with resisted hip adduction, ultrasound imaging of the abdominal musculature on the right side was performed at rest, during the active straight-leg raise (left and right), and during bilateral isometric hip adduction. Athletes then followed a 14-week rehabilitation protocol. Clinical outcome measured by self-reported sports restriction and change in abdominal muscle resting and relative thickness during lower extremity tasks were evaluated. There was an overall significant decrease in self-reported sports restriction after intervention for this group of athletes. Apart from a significant negative correlation for changes in TA resting thickness, no significant association between changes in abdominal muscle thickness and change in self-reported sports restriction were found. Postintervention, TA resting thickness was significantly increased but relative thickness during the lower extremity tasks was found not to be statistically different for all muscles, except for a decreased relative thickness of obliquus externus abdominus (OE) during the active straight-leg raise for the left lower extremity. There was no association between changes in abdominal muscle resting thickness and relative thickness during lower extremity tasks, and change in self-reported sports restriction after a period of

  18. Evaluation of a new carotid intima-media thickness measurement by B-mode ultrasonography using an innovative measurement software, intimascope.

    Science.gov (United States)

    Yanase, Toshihiko; Nasu, Shigeru; Mukuta, Yoshihiro; Shimizu, Yutaka; Nishihara, Tetsu; Okabe, Taijiro; Nomura, Masatoshi; Inoguchi, Toyoshi; Nawata, Hajime

    2006-12-01

    Carotid intima-media thickness (IMT), an indicator of atherosclerosis and coronary heart disease (CHD) is usually evaluated by eye measurement under B-scope carotid artery ultrasonography. However, the axial resolution of this system is >/=0.1 mm, which causes difficulties in respect to accuracy and reproducibility. We evaluated a newly developed B-scope carotid artery ultrasonography programmed by an innovative measurement software, Intimascope (Media Cross Co. Ltd., Tokyo, Japan), which measures IMT with 10 times higher axial resolution at an estimated scale of 0.01 mm. Intraobserver or interobserver coefficient of variation (CV) of the computer-based average IMT (aver-IMT) value and 3-point IMT value were much smaller than the corresponding value by conventional eye-measurement method (3-point value). We measured IMT of 427 asymptomatic subjects undergoing medical checkups (243 men and 184 women, 23 to 73 years of age). Although the mean values of aver-IMT and 3-point IMT of 427 subjects were comparable with that of the eye measurement method, the aver-IMT showed the smallest SD (standard deviation) and CV values. In both men and women, multivariate regression analysis revealed significant contributions of age and LDL-C to the aver-IMT value. Univariate regression analysis revealed that the aver-IMT value of total subjects showed the highest correlation coefficient values with most risk factors and risk assessment score, Framingham Risk Assessment, or Prospective Cardiovascular Munster study (PROCAM) Risk Score. These results may suggest superiority of computer-based aver-IMT over 3-point IMT by either computer-based or eye measurement method. Carotid aver-IMT measurement using the new Intimascope software may provide a more precise and reproducible index of atherosclerosis than does conventional IMT measurement.

  19. SU-F-T-86: Electron Dosimetric Effects of Bolus and Lens Shielding in Treating Superficial Eye Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Young, L [University of Washington Medical Center, Seattle, WA (United States); Wootton, L [University of Washington School of Medicine, Seattle, WA (United States); Gopan, O; Liao, J [University of Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: Electron therapy for the treatment of ocular lymphomas requires the lens to be shielded to prevent secondary cataracts. This work evaluates the dosimetry under a suspended eyeshield with and without bolus for low energy electron fields. Methods: Film (GafChromic EBT3) dosimetry and relative output factors were measured for 6, 8, and 10 MeV electron energies. A customized 5 cm diameter circle electron orbital cutout was constructed for a 6×6 cm applicator with a lens shield, 1 cm diameter Cerrobend cylinder with 2.2 cm length, suspended from an XV film covering the open field. Relative output factors were measured using a Scanditronix electron diode in a solid water phantom. Depth dose profiles were collected for bolus thicknesses of 0, 3, and 5 mm in solid water at a source to surface distance (SSD) of 100 cm. These measurements were repeated in a Rando phantom. Results: At 5 mm, the approximate distance of the lens from the surface of the cornea, the estimated dose in solid water under the suspended lens shield was reduced to 16%, 14%, and 13% of the unblocked dose at the same depth, for electron energies of 6, 8, and 10 MeV, respectively. Applying bolus increased estimated doses under the block to 22% for 3-mm and 32% for 5-mm thicknesses for a 6 MeV incident electron beam. This effect is reduced for higher energies where the corresponding values were 15.5% and 18% for 3-mm and 5-mm for an 8 MeV electron beam. Conclusion: The application of bolus to treat superficial eye lesions of the conjunctiva increases lens dose at a depth of 5-mm under the shielding block with decreasing electron energy. Careful selection of electron energy is needed to account for electron scatter under the lens shield with the application of bolus in order to prevent cataracts.

  20. Ability of spectral domain optical coherence tomography peripapillary retinal nerve fiber layer thickness measurements to identify early glaucoma

    Directory of Open Access Journals (Sweden)

    Tarannum Mansoori

    2011-01-01

    Full Text Available Purpose : To evaluate the ability of spectral domain optical coherence tomography (OCT peripapillary retinal nerve fiber layer thickness (RNFLT parameters to distinguish normal eyes from those with early glaucoma in Asian Indian eyes. Design : Observational cross-sectional study. Materials and Methods : One hundred and seventy eight eyes (83 glaucoma patients and 95 age matched healthy subjects of subjects more than 40 years of age were included in the study. All subjects underwent RNFLT measurement with spectral OCT/ scanning laser ophthalmoscope (SLO after dilatation. Sensitivity, specificity and area under the receiving operating characteristic curve (AROC were calculated for various OCT peripapillary RNFL parameters. Results: The mean RNFLT in healthy subjects and patients with early glaucoma were 105.7 ± 5.1 μm and 90.7 ± 7.5 μm, respectively. The largest AROC was found for 12 o′clock- hour (0.98, average (0.96 and superior quadrant RNFLT (0.9. When target specificity was set at ≥ 90% and ≥ 80%, the parameters with highest sensitivity were 12 o′clock -hour (91.6%, average RNFLT (85.3% and 12 o′ clock- hour (96.8 %, average RNFLT (94.7% respectively. Conclusion : Our study showed good ability of spectral OCT/ SLO to differentiate normal eyes from patients with early glaucoma and hence it may serve as an useful adjunct for early diagnosis of glaucoma.

  1. Choroidal Thickness in Eyes with Fuchs Uveitis Syndrome.

    Science.gov (United States)

    Kardes, Esra; Sezgin Akçay, Betül Ilkay; Unlu, Cihan; Ergin, Ahmet

    2017-04-01

    This study measured the macular thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, subfoveal choroidal thickness (SFCT), and ganglion cell complex (GCC) thickness in eyes with Fuchs uveitis syndrome (FUS). In total, 25 patients with unilateral FUS were enrolled. The diagnosis of FUS was based on the presence of several of the following clinical features: absence of acute symptoms and ciliary injection; small to medium-sized and stellate keratic precipitates (KP) diffusely scattered on the entire corneal endothelium; chronic low-grade anterior chamber inflammation; iris stromal atrophy with or without heterochromia; lack of posterior synechiae; iris nodules; and vitreous cells and debris. Spectral domain optical coherence tomography (SD-OCT; RTVue-100 OCT) was used to obtain the measurements. The SFCT, RNFL thickness, macular retinal thickness, and GCC thickness of the eyes with FUS were measured and compared with those of the uninvolved fellow eyes. A paired samples t-test was used for statistical analyses. A value of pHeterochromia was observed in 24% of the eyes, iris nodules in 36% of the eyes, lens opacity in 44% of the eyes, and vitreous cells and debris in 88% of the eyes. The mean SFCT was significantly thinner in eyes with FUS (296.47 ± 32.29 µm) than in the fellow eyes without FUS (324.47 ± 26.73 µm; p = 0.001). The mean average GCC thickness was found to be 101.09 ± 5.46 µm in eyes with FUS and 103.80 ± 6.65 µm in eyes without FUS (p = 0.023). There were no significant differences in the mean RNFL and macular thickness values. We detected subfoveal choroidal thinning in eyes with FUS when compared with the uninvolved fellow eyes. In our opinion, thinning of the SFCT in FUS might be associated with autoimmune responses and chronic inflammatory processes.

  2. Snow thickness profiling on Antarctic sea ice with GPR—Rapid and accurate measurements with the potential to upscale needles to a haystack

    Science.gov (United States)

    Pfaffhuber, Andreas A.; Lieser, Jan L.; Haas, Christian

    2017-08-01

    Snow thickness on sea ice is a largely undersampled parameter yet of importance for the sea ice mass balance and for satellite-based sea ice thickness estimates and thus our general understanding of global ice volume change. Traditional direct thickness measurements with meter sticks can provide accurate but only spot information, referred to as "needles" due to their pinpoint focus and information, while airborne and satellite remote sensing snow products, referred to as "the haystack," have large uncertainties due to their scale. We demonstrate the remarkable accuracy and applicability of ground-penetrating radar (GPR) snow thickness measurements by comparing them with in situ meter stick data from two field campaigns to Antarctica in late winter/early spring. The efficiency and millimeter-to-centimeter accuracy of GPR enables practitioners to acquire extensive, semiregional data with the potential to upscale needles to the haystack and to potentially calibrate satellite remote sensing products that we confirm to derive roughly 30% of the in situ thickness. We find the radar wave propagation velocity in snow to be rather constant (± 6%), encouraging regional snow thickness surveys. Snow thinner than 10 cm is under the detection limit with the off-the-shelf GPR setup utilized in our study.

  3. Increase of photogenerated carriers in thick quantum wells in InGaN solar cells verified by laser-assisted capacitance-voltage measurement

    Science.gov (United States)

    Liu, Wei; Zhao, Degang; Jiang, Desheng; Chen, Ping; Shi, Dongping; Liu, Zongshun; Zhu, Jianjun; Yang, Jing; Li, Xiang; Liang, Feng; Liu, Shuangtao; Xing, Yao; Zhang, Liqun; Li, Mo; Zhang, Jian

    2017-04-01

    For the InGaN/GaN multiple quantum well (MQW) solar cells, it is known that in the thicker InGaN QWs the collection of photogenerated carriers suffer from the impact of both stronger piezoelectric field and enhanced non-radiative recombination process, which may lead to an inferior performance for thick-well solar cells. However, we find that the photovoltaic intensities of our MQW solar cells with different well thickness are almost the same. Combined with the profiles of apparent carrier concentration obtained from the capacitance-voltage measurement with additional laser illumination, we conclude that the increase of photogenerated carriers in the thick QWs may partially counteract the adverse effects of both polarization effect and deteriorated material quality on the photocurrent for the MQW solar cells with thick InGaN well layers, compared with the thin-well ones.

  4. Apparent temperature versus true temperature of silicon crystals as a function of their thickness using infrared measurements

    International Nuclear Information System (INIS)

    Smither, R.K.; Fernandez, P.B.

    1993-01-01

    The very high intensity x-ray beams that will be present at the Advanced Photon Source and other third generation synchrotron sources will require that the first optical element in the beamline and, possibly, the second optical element as well, be cooled to remove the heat deposited by the x-ray beam. In many of the beamlines this heat will be in the 1 to 5 kW range, and any failure of the cooling system will require a quick response from safety control circuits to shut off the beam before damage is done to the optical element. In many cases, this first optical element will be a silicon diffraction crystal. Viewing the surface of objects subjected to high heat fluxes with an infrared camera or infrared sensor has proved to be a very effective method for monitoring the magnitude and distribution of surface temperatures on the object. This approach has been quite useful in studies of cooling silicon crystals in monochromators subject to high heat loads. The main drawback to this method is that single crystals of silicon are partially transparent to the infrared radiation monitored in most infrared cameras. This means that the infrared radiation emitted from the surface contains a component that comes from the interior of the crystal and that the intensity of the emitted radiation and thus the apparent temperature of the surface of the crystal depends on the thickness of the crystal and the kind of coating on the back (and/or the front) of the crystal. The apparent temperature of the crystal increases as the crystal is made thicker. A series of experiments were performed at Argonne National Laboratory to calibrate the apparent surface temperature of the crystal as measured with an infrared camera as a function of the crystal thickness and the type of coating (if any) on the back side of the crystal. A number of examples are given for data taken in synchrotron experiments with high intensity x-ray beams

  5. Validation of ultrasonographic muscle thickness measurements as compared to the gold standard of computed tomography in dogs

    Directory of Open Access Journals (Sweden)

    Lindsey E. Bullen

    2017-01-01

    Full Text Available Objective The objective was to quantitatively evaluate the validity of ultrasonographic (US muscle measurements as compared to the gold standard of computed tomography (CT in the canine. Design This was a prospective study. Population Twenty-five, client-owned dogs scheduled for CT as part of a diagnostic work-up for the management of their primary disease process were included. Materials and Methods Specific appendicular (cubital flexors and extensors, coxofemoral flexors and extensors and axial (temporalis, supraspinatus, infraspinatus, lumbar epaxials muscle groups were selected for quantitative measure based on CT planning and patient position. Prior to CT scan, the skin over the muscle sites was shaved and marked with a permanent marker. Patient body position was determined based on the patient’s CT plan; positioning was consistent between CT and US imaging. To ensure identical imaging position for both CT and US measurements, radio-opaque fiducial markers were placed directly over the skin marks once the dog was positioned. Quantitative measurements (cm for both lean muscle mass (LMM and subcutaneous adipose (SQA were recorded. Statistical comparisons between CT and US values were done separately for each site and type. Results Muscle groups and associated SQA measured by US and CT were not statistically different based on an adjusted p-value using Bonferroni’s correction (p 0.897 for LLM and >0.8289 for SQA. Conclusions Ultrasound imaging of selected appendicular and axial muscle groups in dogs can provide comparable assessment of muscle thickness to the current gold standard, CT. In consideration of both statistical reliability to CT and cage-side accessibility, the temporalis, supraspinatus, infraspinatus, and lumbar epaxial LMM sites are considered the most useful targets for US LMM assessment in the canine. Our findings support the potential utility of US as a clinical tool in veterinary medicine to assess LMM status in patients

  6. Thin dielectric film thickness determination by advanced transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diebold, A.C.; Foran, B.; Kisielowski, C.; Muller, D.; Pennycook, S.; Principe, E.; Stemmer, S.

    2003-09-01

    High Resolution Transmission Electron Microscopy (HR-TEM) has been used as the ultimate method of thickness measurement for thin films. The appearance of phase contrast interference patterns in HR-TEM images has long been confused as the appearance of a crystal lattice by non-specialists. Relatively easy to interpret crystal lattice images are now directly observed with the introduction of annular dark field detectors for scanning TEM (STEM). With the recent development of reliable lattice image processing software that creates crystal structure images from phase contrast data, HR-TEM can also provide crystal lattice images. The resolution of both methods was steadily improved reaching now into the sub Angstrom region. Improvements in electron lens and image analysis software are increasing the spatial resolution of both methods. Optimum resolution for STEM requires that the probe beam be highly localized. In STEM, beam localization is enhanced by selection of the correct aperture. When STEM measurement is done using a highly localized probe beam, HR-TEM and STEM measurement of the thickness of silicon oxynitride films agree within experimental error. In this paper, the optimum conditions for HR-TEM and STEM measurement are discussed along with a method for repeatable film thickness determination. The impact of sample thickness is also discussed. The key result in this paper is the proposal of a reproducible method for film thickness determination.

  7. Novel fabrication technique of hybrid structure lens array for 3D images

    Science.gov (United States)

    Lee, Junsik; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Koo, Gyohyun; Won, Yong Hyub

    2016-03-01

    Tunable liquid lens arrays can produce three dimensional images by using electrowetting principle that alters surface tensions by applying voltage. This method has advantages of fast response time and low power consumption. However, it is challenging to fabricate a high fill factor liquid lens array and operate three dimensional images which demand high diopter. This study describes a hybrid structure lens array which has not only a liquid lens array but a solid lens array. A concave-shape lens array is unavoidable when using only the liquid lens array and some voltages are needed to make the lens flat. By placing the solid lens array on the liquid lens array, initial diopter can be positive. To fabricate the hybrid structure lens array, a conventional lithographic process in semiconductor manufacturing is needed. A negative photoresist SU-8 was used as chamber master molds. PDMS and UV adhesive replica molding are done sequentially. Two immiscible liquids, DI water and dodecane, are injected in the fabricated chamber, followed by sealing. The fabricated structure has a 20 by 20 pattern of cylindrical shaped circle array and the aperture size of each lens is 1mm. The thickness of the overall hybrid structure is about 2.8mm. Hybrid structure lens array has many advantages. Solid lens array has almost 100% fill factor and allow high efficiency. Diopter can be increased by more than 200 and negative diopter can be shifted to the positive region. This experiment showed several properties of the hybrid structure and demonstrated its superiority.

  8. Validation of high-resolution aerosol optical thickness simulated by a global non-hydrostatic model against remote sensing measurements

    Science.gov (United States)

    Goto, Daisuke; Sato, Yousuke; Yashiro, Hisashi; Suzuki, Kentaroh; Nakajima, Teruyuki

    2017-02-01

    A high-performance computing resource allows us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems. The cutting-edge computational capability, which was provided by the K computer at RIKEN in Japan, enabled the authors to perform long-term, global simulations of air pollutions and clouds with unprecedentedly high horizontal resolutions. In this study, a next generation model capable of simulating global air pollutions with O(10 km) grid spacing by coupling an atmospheric chemistry model to the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) was performed. Using the newly developed model, month-long simulations for July were conducted with 14 km grid spacing on the K computer. Regarding the global distributions of aerosol optical thickness (AOT), it was found that the correlation coefficient (CC) between the simulation and AERONET measurements was approximately 0.7, and the normalized mean bias was -10%. The simulated AOT was also compared with satellite-retrieved values; the CC was approximately 0.6. The radiative effects due to each chemical species (dust, sea salt, organics, and sulfate) were also calculated and compared with multiple measurements. As a result, the simulated fluxes of upward shortwave radiation at the top of atmosphere and the surface compared well with the observed values, whereas those of downward shortwave radiation at the surface were underestimated, even if all aerosol components were considered. However, the aerosol radiative effects on the downward shortwave flux at the surface were found to be as high as 10 W/m2 in a global scale; thus, simulated aerosol distributions can strongly affect the simulated air temperature and dynamic circulation.

  9. Comparison of central corneal thickness and endothelial cell measurements by Scheimpflug camera system and two noncontact specular microscopes.

    Science.gov (United States)

    Karaca, Irmak; Yilmaz, Suzan Guven; Palamar, Melis; Ates, Halil

    2017-07-03

    To investigate the correlation of Scheimpflug camera system and two noncontact specular microscopes in terms of central corneal thickness (CCT) and corneal endothelial cell morphology measurements. One hundred eyes of 50 healthy subjects were examined by Pentacam Scheimpflug Analyzer, CEM-530 (Nidek Co, Ltd, Gamagori, Japan) and CellChek XL (Konan Medical, California, USA) via fully automated image analysis with no corrections made. Measurement differences and agreement between instruments were determined by intraclass correlation analysis. The mean age of the subjects was 36.74 ± 8.59 (range 22-57). CCTs were well correlated among all devices, with having CEM-530 the thinnest and CellChek XL the thickest measurements (intraclass correlation coefficient (ICC) = 0.83; p < 0.001 and ICC = 0.78; p < 0.001, respectively). Mean endothelial cell density (ECD) given by CEM-530 was lower than CellChek XL (2613.17 ± 228.62 and 2862.72 ± 170.42 cells/mm 2 , respectively; ICC = 0.43; p < 0.001). Mean value for coefficient of variation (CV) was 28.57 ± 3.61 in CEM-530 and 30.30 ± 3.53 in CellChek XL. Cell hexagonality (HEX) with CEM-530 was higher than with CellChek XL (68.70 ± 4.16% and 45.19 ± 6.58%, respectively). ECDs with CellChek XL and CEM-530 have good correlation, but the values obtained by CellChek XL are higher than CEM-530. Measurements for HEX and CV differ significantly and show weak correlation. Thus, we do not recommend interchangeable use of CellChek XL and CEM-530. In terms of CCTs, Pentacam, CEM-530 and CellChek XL specular microscopy instruments are reliable devices.

  10. SDOCT Thickness Measurements of Various Retinal Layers in Patients with Autosomal Dominant Optic Atrophy due to OPA1 Mutations

    Directory of Open Access Journals (Sweden)

    Andrea M. Schild

    2013-01-01

    Full Text Available Purpose. To specify thickness values of various retinal layers on macular spectral domain Optical Coherence Tomography (SDOCT scans in patients with autosomal dominant optic atrophy (ADOA compared to healthy controls. Methods. SDOCT volume scans of 7 patients with ADOA (OPA-1 mutation and 14 healthy controls were quantitatively analyzed using manual grading software. Mean thickness values for the ETDRS grid subfields 5–8 were calculated for the spaces neurosensory retina, retinal nerve fiber layer (RNFL, ganglion cell layer (GCL, a combined space of inner plexiform layer/outer plexiform layer/inner nuclear layer (IPL+INL+OPL, and a combined space of outer nuclear layer/photoreceptor layers (ONL+PL. Results. ADOA patients showed statistically significant lower retinal thickness values than controls (. RNFL ( and GCL thicknesses ( were significantly lower in ADOA patients. There was no difference in IPL+INL+OPL and in ONL+PL thickness. Conclusion. Manual subanalysis of macular SDOCT volume scans allowed detailed subanalysis of various retinal layers. Not only RNFL but also GCL thicknesses are reduced in the macular area of ADOA patients whereas subjacent layers are not involved. Together with clinical findings, macular SDOCT helps to identify patients with suspicion for hereditary optic neuropathy before genetic analysis confirms the diagnosis.

  11. Thick-target method in the measurement of inner-shell ionization cross-sections by low-energy electron impact

    International Nuclear Information System (INIS)

    An, Z.; Wu, Y.; Liu, M.T.; Duan, Y.M.; Tang, C.H.

    2006-01-01

    In this paper, we have studied the thick-target method for the measurements of atomic inner-shell ionization cross-section or X-ray production cross-section by keV electron impact. We find that in the processes of electron impact on the thick targets, the ratios of the characteristic X-ray yields of photoelectric ionization by bremsstrahlung to the total characteristic X-ray yields are Z-dependent and shell-dependent, and the ratios also show the weak energy-dependence. In addition, in the lower incident energy region (i.e. U < 5-6), the contribution from the rediffusion effect and the secondary electrons can be negligible. In general, the thick-target method can be appropriately applied to the measurements of atomic inner-shell ionization cross-sections or X-ray production cross-sections by electron impact for low and medium Z elements in the lower incident electron energy (i.e. U < 5-6). The experimental accuracies by the thick-target method can reach to the level equivalent or superior to the accuracies of experimental data based on the thin-target method. This thick-target method has been applied to the measurement of K-shell ionization cross-sections of Ni element by electron impact in this paper

  12. The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography.

    Science.gov (United States)

    Kok, Pauline H B; van den Berg, Thomas J T P; van Dijk, Hille W; Stehouwer, Marilette; van der Meulen, Ivanka J E; Mourits, Maarten P; Verbraak, Frank D

    2013-08-01

    The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. SDOCT images, made with two different devices (3DOCT-1000, Topcon and Cirrus HD-OCT), before and after cataract surgery were compared and judged against measurements from normal subjects using artificial filters simulating the effects of cataract. Optical density of the images was calculated based on a mathematical model described previously. In total, forty-eight eyes were included for pre- and postoperative cataract extraction measurements. OCT image quality significantly (p optical density and change in RNFL thickness (R = 0.941, p optical density of cataract and the cataract-induced underestimation was however limited, and mean difference ± SD between predicted and measured RNFL thickness were 1.68 ± 7.55 (3DOCT-1000) and 3.71 ± 2.97 (Cirrus HD-OCT) micron. A linear relationship exists between OCT-effective optical density of cataract and underestimation of RNFL thickness measured with OCT. This finding holds promise to correct for cataract-induced changes in RNFL measurements, but will differ for each type of OCT device. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  13. Simultaneous determination of aerosol optical thickness and water-leaving radiance from multispectral measurements in coastal waters

    Science.gov (United States)

    Shi, Chong; Nakajima, Teruyuki

    2018-03-01

    Retrieval of aerosol optical properties and water-leaving radiance over ocean is challenging since the latter mostly accounts for ˜ 10 % of the satellite-observed signal and can be easily influenced by the atmospheric scattering. Such an effort would be more difficult in turbid coastal waters due to the existence of optically complex oceanic substances or high aerosol loading. In an effort to solve such problems, we present an optimization approach for the simultaneous determination of aerosol optical thickness (AOT) and normalized water-leaving radiance (nLw) from multispectral satellite measurements. In this algorithm, a coupled atmosphere-ocean radiative transfer model combined with a comprehensive bio-optical oceanic module is used to jointly simulate the satellite-observed reflectance at the top of atmosphere and water-leaving radiance just above the ocean surface. Then, an optimal estimation method is adopted to retrieve AOT and nLw iteratively. The algorithm is validated using Aerosol Robotic Network - Ocean Color (AERONET-OC) products selected from eight OC sites distributed over different waters, consisting of observations that covered glint and non-glint conditions from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. Results show a good consistency between retrieved and in situ measurements at each site. It is demonstrated that more accurate AOTs are determined based on the simultaneous retrieval method, particularly in shorter wavelengths and sunglint conditions, where the averaged percentage difference (APD) of retrieved AOT is generally reduced by approximate 10 % in visible bands compared with those derived from the standard atmospheric correction (AC) scheme, since all the spectral measurements can be used jointly to increase the information content in the inversion of AOT, and the wind speed is also simultaneously retrieved to compensate the specular reflectance error estimated from the rough ocean surface model. For the

  14. Survival prediction using temporal muscle thickness measurements on cranial magnetic resonance images in patients with newly diagnosed brain metastases

    Energy Technology Data Exchange (ETDEWEB)

    Furtner, Julia; Prayer, Daniela [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumor Unit (CCC-CNS), Vienna (Austria); Berghoff, Anna S.; Zielinski, Christoph C.; Preusser, Matthias [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumor Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Medicine I, Vienna (Austria); Albtoush, Omar M. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); University of Jordan, Department of Radiology and Nuclear Medicine, Amman (Jordan); Woitek, Ramona; Asenbaum, Ulrika [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Widhalm, Georg; Gatterbauer, Brigitte [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumor Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Neurosurgery, Vienna (Austria); Dieckmann, Karin [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumor Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Radiotherapy, Vienna (Austria); Birner, Peter [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumor Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Medicine I, Vienna (Austria); Medical University of Vienna, Department of Pathology, Vienna (Austria); Aretin, Bernadette [General Hospital Vienna, Pharmacy Department, Vienna (Austria); Bartsch, Rupert [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumor Unit (CCC-CNS), Vienna (Austria); Schoepf, Veronika [University of Graz, Institute of Psychology, Graz (Austria); BioTechMed, Graz (Austria)

    2017-08-15

    To evaluate the prognostic relevance of temporal muscle thickness (TMT) in brain metastasis patients. We retrospectively analysed TMT on magnetic resonance (MR) images at diagnosis of brain metastasis in two independent cohorts of 188 breast cancer (BC) and 247 non-small cell lung cancer (NSCLC) patients (overall: 435 patients). Survival analysis using a Cox regression model showed a reduced risk of death by 19% with every additional millimetre of baseline TMT in the BC cohort and by 24% in the NSCLC cohort. Multivariate analysis included TMT and diagnosis-specific graded prognostic assessment (DS-GPA) as covariates in the BC cohort (TMT: HR 0.791/CI [0.703-0.889]/p < 0.001; DS-GPA: HR 1.433/CI [1.160-1.771]/p = 0.001), and TMT, gender and DS-GPA in the NSCLC cohort (TMT: HR 0.710/CI [0.646-0.780]/p < 0.001; gender: HR 0.516/CI [0.387-0.687]/p < 0.001; DS-GPA: HR 1.205/CI [1.018-1.426]/p = 0.030). TMT is easily and reproducibly assessable on routine MR images and is an independent predictor of survival in patients with newly diagnosed brain metastasis from BC and NSCLC. TMT may help to better define frail patient populations and thus facilitate patient selection for therapeutic measures or clinical trials. Further prospective studies are needed to correlate TMT with other clinical frailty parameters of patients. (orig.)

  15. Extrapolating active layer thickness measurements across Arctic polygonal terrain using LiDAR and NDVI data sets.

    Science.gov (United States)

    Gangodagamage, Chandana; Rowland, Joel C; Hubbard, Susan S; Brumby, Steven P; Liljedahl, Anna K; Wainwright, Haruko; Wilson, Cathy J; Altmann, Garrett L; Dafflon, Baptiste; Peterson, John; Ulrich, Craig; Tweedie, Craig E; Wullschleger, Stan D

    2014-08-01

    Landscape attributes that vary with microtopography, such as active layer thickness ( ALT ), are labor intensive and difficult to document effectively through in situ methods at kilometer spatial extents, thus rendering remotely sensed methods desirable. Spatially explicit estimates of ALT can provide critically needed data for parameterization, initialization, and evaluation of Arctic terrestrial models. In this work, we demonstrate a new approach using high-resolution remotely sensed data for estimating centimeter-scale ALT in a 5 km 2 area of ice-wedge polygon terrain in Barrow, Alaska. We use a simple regression-based, machine learning data-fusion algorithm that uses topographic and spectral metrics derived from multisensor data (LiDAR and WorldView-2) to estimate ALT (2 m spatial resolution) across the study area. Comparison of the ALT estimates with ground-based measurements, indicates the accuracy (r 2  = 0.76, RMSE ±4.4 cm) of the approach. While it is generally accepted that broad climatic variability associated with increasing air temperature will govern the regional averages of ALT , consistent with prior studies, our findings using high-resolution LiDAR and WorldView-2 data, show that smaller-scale variability in ALT is controlled by local eco-hydro-geomorphic factors. This work demonstrates a path forward for mapping ALT at high spatial resolution and across sufficiently large regions for improved understanding and predictions of coupled dynamics among permafrost, hydrology, and land-surface processes from readily available remote sensing data.

  16. Extrapolating active layer thickness measurements across Arctic polygonal terrain using LiDAR and NDVI data sets

    Science.gov (United States)

    Gangodagamage, Chandana; Rowland, Joel C; Hubbard, Susan S; Brumby, Steven P; Liljedahl, Anna K; Wainwright, Haruko; Wilson, Cathy J; Altmann, Garrett L; Dafflon, Baptiste; Peterson, John; Ulrich, Craig; Tweedie, Craig E; Wullschleger, Stan D

    2014-01-01

    Landscape attributes that vary with microtopography, such as active layer thickness (ALT), are labor intensive and difficult to document effectively through in situ methods at kilometer spatial extents, thus rendering remotely sensed methods desirable. Spatially explicit estimates of ALT can provide critically needed data for parameterization, initialization, and evaluation of Arctic terrestrial models. In this work, we demonstrate a new approach using high-resolution remotely sensed data for estimating centimeter-scale ALT in a 5 km2 area of ice-wedge polygon terrain in Barrow, Alaska. We use a simple regression-based, machine learning data-fusion algorithm that uses topographic and spectral metrics derived from multisensor data (LiDAR and WorldView-2) to estimate ALT (2 m spatial resolution) across the study area. Comparison of the ALT estimates with ground-based measurements, indicates the accuracy (r2 = 0.76, RMSE ±4.4 cm) of the approach. While it is generally accepted that broad climatic variability associated with increasing air temperature will govern the regional averages of ALT, consistent with prior studies, our findings using high-resolution LiDAR and WorldView-2 data, show that smaller-scale variability in ALT is controlled by local eco-hydro-geomorphic factors. This work demonstrates a path forward for mapping ALT at high spatial resolution and across sufficiently large regions for improved understanding and predictions of coupled dynamics among permafrost, hydrology, and land-surface processes from readily available remote sensing data. PMID:25558114

  17. A lazy way to design infrared lens

    Science.gov (United States)

    Qiu, RongSheng; Wu, JianDong; Chen, LongJiang; Yu, Kun; Pang, HaoJun; Hu, BaiZhen

    2017-08-01

    We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn't change a lot during a temperature range of -40°C +60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

  18. Corneal Epithelial Thickness Measured by Manual Electronic Caliper Spectral Domain Optical Coherence Tomography: Distributions and Demographic Correlations in Preoperative Refractive Surgery Patients.

    Science.gov (United States)

    Rush, Sloan W; Matulich, Jennifer; Biskup, Joel; Cofoid, Philip; Rush, Ryan B

    2016-01-01

    The aim of this study was to report the distributions and demographic correlations of corneal epithelial thickness measured by manual electronic caliper spectral domain optical coherence tomography in preoperative refractive surgery patients. This was a retrospective review. The charts of 218 consecutive patients (413 eyes) who presented for refractive surgery evaluation from April 2013 through September 2013 were retrospectively reviewed. The mean corneal epithelial thickness was 51.0 μm with a range of 43 to 61 μm. Corneal epithelial thickness was significantly correlated with sex (P caliper optical coherence tomography in preoperative refractive surgery patients is comparable with the findings for the general population using other measurement techniques, the awareness of which may be useful in the preoperative assessment of these patients.

  19. Measuring the Thickness and Potential Profiles of the Space-Charge Layer at Organic/Organic Interfaces under Illumination and in the Dark by Scanning Kelvin Probe Microscopy.

    Science.gov (United States)

    Rojas, Geoffrey A; Wu, Yanfei; Haugstad, Greg; Frisbie, C Daniel

    2016-03-09

    Scanning Kelvin probe microscopy was used to measure band-bending at the model donor/acceptor heterojunction poly(3-hexylthiophene) (P3HT)/fullerene (C60). Specifically, we measured the variation in the surface potential of C60 films with increasing thicknesses grown on P3HT to produce a surface potential profile normal to the substrate both in the dark and under illumination. The results confirm a space-charge carrier region with a thickness of 10 nm, consistent with previous observations. We discuss the possibility that the domain size in bulk heterojunction organic solar cells, which is comparable to the space-charge layer thickness, is actually partly responsible for less than expected electron/hole recombination rates.

  20. Palatal bone thickness measured by palatal index method using cone-beam computed tomography in nonorthodontic patients for placement of mini-implants

    Director