WorldWideScience

Sample records for surface height measurements

  1. Interferometric Surface Relief Measurements with Subnano/Picometer Height Resolution

    Science.gov (United States)

    Sysoev, Evgeny; Kosolobov, Sergey; Kulikov, Rodion; Latyshev, Alexander; Sitnikov, Sergey; Vykhristyuk, Ignat

    2017-10-01

    We present an optical interference system nanoprofiler MNP-1 designed for high-precision noncontact measurement of surface relief with subnanometer resolution (root mean square of measured values), based on partial scanning of interference signal. The paper describes the construction of the measurement system with Linnik interferometer and the algorithm for nanorelief surface reconstruction. Experimental measurement results of silicon sample with profile height of surface structure of one interatomic distance obtained by MNP-1 are shown. It was proposed to use an atomically smooth surface as the reference mirror in the interferometer MNP-1 that allowed us to measure monatomic steps of the presented silicon sample. Monatomic steps of 0.31 nm in height on silicon (111) surface were measured with resolution up to 5 pm.

  2. Measuring sea surface height with a GNSS-Wave Glider

    Science.gov (United States)

    Morales Maqueda, Miguel Angel; Penna, Nigel T.; Foden, Peter R.; Martin, Ian; Cipollini, Paolo; Williams, Simon D.; Pugh, Jeff P.

    2017-04-01

    A GNSS-Wave Glider is a novel technique to measure sea surface height autonomously using the Global Navigation Satellite System (GNSS). It consists of an unmanned surface vehicle manufactured by Liquid Robotics, a Wave Glider, and a geodetic-grade GNSS antenna-receiver system, with the antenna installed on a mast on the vehicle's deck. The Wave Glider uses the differential wave motion through the water column for propulsion, thus guaranteeing an, in principle, indefinite autonomy. Solar energy is collected to power all on-board instrumentation, including the GNSS system. The GNSS-Wave Glider was first tested in Loch Ness in 2013, demonstrating that the technology is capable of mapping geoid heights within the loch with an accuracy of a few centimetres. The trial in Loch Ness did not conclusively confirm the reliability of the technique because, during the tests, the state of the water surface was much more benign than would normally be expect in the open ocean. We now report on a first deployment of a GNSS-Wave Glider in the North Sea. The deployment took place in August 2016 and lasted thirteen days, during which the vehicle covered a distance of about 350 nautical miles in the north western North Sea off Great Britain. During the experiment, the GNSS-Wave Glider experienced sea states between 1 (0-0.1 m wave heights) and 5 (2.5-4 m wave heights). The GNSS-Wave Glider data, recorded at 5 Hz frequency, were analysed using a post-processed kinematic GPS-GLONASS precise point positioning (PPP) approach, which were quality controlled using double difference GPS kinematic processing with respect to onshore reference stations. Filtered with a 900 s moving-average window, the PPP heights reveal geoid patterns in the survey area that are very similar to the EGM2008 geoid model, thus demonstrating the potential use of a GNSS-Wave Glider for marine geoid determination. The residual of subtracting the modelled or measured marine geoid from the PPP signal combines information

  3. Optical triangulation method for height measurements on water surfaces

    Science.gov (United States)

    Maas, Hans-Gerd; Hentschel, Bernd; Schreiber, Frank

    2003-01-01

    Optical triangulation methods based on a laser light sheet and a camera are frequently used as a surface measurement technique in a wide range of applications. They allow for the fast accurate determination of height profiles, based on relatively simple hardware and software configurations. Moreover, they can be implemented very efficiently and are especially suited for measurements on moving objects such as products on an assembly line. The study presented in the paper describes the adaptation of laser light sheet optical triangulation techniques to the task of water level profile measurements in hydromechanics experimental facilities. The properties of water surfaces necessitate several modifications of optical triangulation techniques to make them applicable: The mirror-like reflection properties of water surfaces form a contradiction to the assumption of diffuse reflection, on which standard light sheet triangulation techniques are based; this problem can be circumvented by using a diffuse reflecting projection plane to capture the mirror-like reflection of the laser line from the water surface. Due to the angle of incidence law, however, water surface tilts caused by waves will usually cause a strong degradation of the quality of the results when using reflected light; this effect can largely be compensated by processing max-store images derived from short image sequences rather than single images. These extensions of optical triangulation turned out to be crucial for the applicability of the method on water surfaces. Besides the theoretical concept and a sensitivity analysis of the method, a system configuration is outlined, and the results of a number of practical experiments are shown and discussed.

  4. Step-height measurements on sand surfaces: A comparison between optical scanner and coordinate measuring machine

    DEFF Research Database (Denmark)

    Mohaghegh, Kamran; Yazdanbakhsh, Seyed Alireza; Tiedje, Niels Skat

    2016-01-01

    the same routine to touch the different positions on the polygonised mesh. Each measurement was repeated 5 times. The results of step height measurements on sand surfaces showed a maximum error of ± 12 µm for CMM, while scanner shows only ± 4 µm. Generally speaking, optical step height values were measured...

  5. Digital holography on moving objects: multiwavelength height measurements on inclined surfaces

    Science.gov (United States)

    Schiller, Annelie; Beckmann, Tobias; Fratz, Markus; Belzer, Dominik; Bertz, Alexander; Carl, Daniel; Buse, Karsten

    2017-06-01

    Multiwavelength digital holography on moving objects enables fast and precise inline-measurements of surface pro files. Due to the use of multiple wavelengths, optically rough surfaces with structure heights in the micrometer range can be mapped unambiguously. In this work we explore the influence of the object velocity on height measurements on inclined surfaces. We show measurements using spatial-phase-shifting holography employing two wavelengths and object velocities of up to 90 mm/s with eye-safe cw-lasers with less than 1 mW of laser light. Despite motion blur exceeding the mean speckle size, reliable height measurements can be conducted at these velocities. The height map of a metal cone with two different slope angles (1° , 10° ) is measured at an exposure time of 2 ms. Using line shaped illumination, each frame yields a height map of approximately 2 x 17 mm2. The overlap between the frames allows averaging as the image is put together, improving data quality. The mean repeatability of the height information in the investigated setup is better than 4.5 µm at a synthetic wavelength of 214 µm.

  6. Step-height measurements on sand surfaces: A comparison between optical scanner and coordinate measuring machine

    DEFF Research Database (Denmark)

    Mohaghegh, Kamran; Yazdanbakhsh, Seyed Alireza; Tiedje, Niels Skat

    2016-01-01

    based on triangulation principle using fringe projection was also used to measure the step heights resulting in a point cloud for each scanning. A similar measurement procedure with scanner was made using the scanners software to simulate a ball probe with the same size of CMM probe and following....... In this work step-heights ranging from 0.1 mm to 5.0 mm were made on 6 customised sand samples with an average grain size of 230 µm, produced using a hard binder that can be scanned both by tactile and optical probes. The step-heights were measured using a CMM with ø8 mm tactile probe. An optical 3D scanner...

  7. Continuous measurements of water surface height and width along a 6.5km river reach for discharge algorithm development

    Science.gov (United States)

    Tuozzolo, S.; Durand, M. T.; Pavelsky, T.; Pentecost, J.

    2015-12-01

    The upcoming Surface Water and Ocean Topography (SWOT) satellite will provide measurements of river width and water surface elevation and slope along continuous swaths of world rivers. Understanding water surface slope and width dynamics in river reaches is important for both developing and validating discharge algorithms to be used on future SWOT data. We collected water surface elevation and river width data along a 6.5km stretch of the Olentangy River in Columbus, Ohio from October to December 2014. Continuous measurements of water surface height were supplemented with periodical river width measurements at twenty sites along the study reach. The water surface slope of the entire reach ranged from during 41.58 cm/km at baseflow to 45.31 cm/km after a storm event. The study reach was also broken into sub-reaches roughly 1km in length to study smaller scale slope dynamics. The furthest upstream sub-reaches are characterized by free-flowing riffle-pool sequences, while the furthest downstream sub-reaches were directly affected by two low-head dams. In the sub-reaches immediately upstream of each dam, baseflow slope is as low as 2 cm/km, while the furthest upstream free-flowing sub-reach has a baseflow slope of 100 cm/km. During high flow events the backwater effect of the dams was observed to propagate upstream: sub-reaches impounded by the dams had increased water surface slopes, while free flowing sub-reaches had decreased water surface slopes. During the largest observed flow event, a stage change of 0.40 m affected sub-reach slopes by as much as 30 cm/km. Further analysis will examine height-width relationships within the study reach and relate cross-sectional flow area to river stage. These relationships can be used in conjunction with slope data to estimate discharge using a modified Manning's equation, and are a core component of discharge algorithms being developed for the SWOT mission.

  8. Expected Performance of the Upcoming Surface Water and Ocean Topography Mission Measurements of River Height, Width, and Slope

    Science.gov (United States)

    Wei, R.; Frasson, R. P. M.; Williams, B. A.; Rodriguez, E.; Pavelsky, T.; Altenau, E. H.; Durand, M. T.

    2017-12-01

    The upcoming Surface Water and Ocean Topography (SWOT) mission will measure river widths and water surface elevations of rivers wider than 100 m. In preparation for the SWOT mission, the Jet Propulsion Laboratory built the SWOT hydrology simulator with the intent of generating synthetic SWOT overpasses over rivers with realistic error characteristics. These synthetic overpasses can be used to guide the design of processing methods and data products, as well as develop data assimilation techniques that will incorporate the future SWOT data into hydraulic and hydrologic models as soon as the satellite becomes operational. SWOT simulator uses as inputs water depth, river bathymetry, and the surrounding terrain digital elevation model to create simulated interferograms of the study area. Next, the simulator emulates the anticipated processing of SWOT data by attempting to geolocate and classify the radar returns. The resulting cloud of points include information on water surface elevation, pixel area, and surface classification (land vs water). Finally, we process the pixel clouds by grouping pixels into equally spaced nodes located at the river centerline. This study applies the SWOT simulator to six different rivers: Sacramento River, Tanana River, Saint Lawrence River, Platte River, Po River, and Amazon River. This collection of rivers covers a range of size, slope, and planform complexity with the intent of evaluating the impact of river width, slope, planform complexity, and surrounding topography on the anticipated SWOT height, width, and slope error characteristics.

  9. Agreement between measured height, and height predicted from ...

    African Journals Online (AJOL)

    accurate predictor of height in forensic science, but cannot be directly measured in living patients.32 In a recent study in a public hospital in Brazil, it was indeed found that height prediction equations based on knee height outperformed those based on. Discrepancies of up to 19.8 cm were recorded, which is clinically.

  10. OW AVISO Sea-Surface Height & Niiler Climatology

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains satellite-derived sea-surface height measurements collected by means of the TOPEX/Poseidon/ERS, JASON-1/Envisat, and Jason-2/Envisat satellite...

  11. Ultrasound measured testicular volume in Nigerian adults: Relationship of the three formulae with height, body weight, body-surface area, and body-mass index

    Directory of Open Access Journals (Sweden)

    Madubogwu Chimezie Innocent

    2016-01-01

    Full Text Available Background: Measurement of testicular volume is one of the ways of assessing testicular function. Ultrasonography is an important and accurate radiological method for measurement of testicular volume. Objective: This study was aimed at evaluating the relationship of ultrasound measured testicular volume using the three formulae with the subjects' height, body weight, body surface area (BSA, and body mass index (BMI in adults. Methodology: One hundred twenty-five adult male subjects comprising staff and students of a University Teaching Hospital were recruited into the study. Height and body weight were measured while the BMI and BSA were calculated. Ultrasound measurement of the height, length, and width of both testes were done and used to calculate the volumes using the three formulae. Results: The subjects' age ranged from 19 to 29 years with a mean of 23.48 ± 2.26 yrs. The mean ultrasound measured volumes for the right and left testes were 15.38 ± 3.29 ml and 15.29 ± 3.89 ml using the prolate ellipsoid formula; 22.86 ± 5.43 ml and 23.54 ± 6.88 ml by the prolate spheroid formula; 21.20 ± 5.28 ml and 20.87 ± 5.35 ml by the Lambert formula, respectively. The calculated mean for height, body weight, BMI, and BSA were 174.64 ± 6.36 cm, 68.68 ± 8.25 kg, 22.48 ± 2.17 kg/m2, and 1.82 ± 0.13 m2, respectively. The right testes showed a negative correlation, while the left and combined testicular volumes showed a positive correlation with the subjects' height, body weight, BMI, and BSA for all the three formulae. Conclusion: The right testicular volume showed negative correlation, while the left and combined testicular volumes showed a positive correlation with the height, body weight, BSA, and BMI in Nigerian adults.

  12. Height, surface firmness, and visual reference effects on balance control.

    Science.gov (United States)

    Simeonov, P; Hsiao, H

    2001-09-01

    To investigate the effects of height, surface firmness, and visual reference on standing balance in construction workers. Controlled laboratory study with balanced repeated measures. Twenty four construction workers. Test subjects performed standing tasks at ground level as well as at 3 m and 9 m high balconies on firm or deformable surfaces with close visual references included or excluded from their visual field. Standing balance was determined from center of pressure as measured by a force platform. Dependent variables were root mean square of sway in medial-lateral and anterior-posterior directions, area of sway, and velocity of sway. Heights without close visual references significantly increased all sway parameters. The effect of height in conditions without close visual references increased dramatically on deformable surfaces. Elevated work environments and deformable work surfaces negatively affect balance and may be associated with increased risk of fall incidents. Appropriate close visual references increase the ability to maintain balance.

  13. Derivation of Orthometric Heights from GPS Measured Heights ...

    African Journals Online (AJOL)

    In this study, geometric technique of deriving orthometric height from GPS survey along a profile and the use of EGM 96 geoid model for deriving orthometric height from GPS data (using GNSS solution software) are discussed. The main focus of the research is to critically examine the potentials of these methods with a view ...

  14. Symphysis Fundus Height Measurements during Labour: A ...

    African Journals Online (AJOL)

    This study was conducted to determine the correlation between symphysis fundus height (SFH) measurements and infant weight. It was also to examine whether descent of the fetus or rupture of the membranes affects the relationship and to calculate a simple formula for estimation of fetal weight. A descriptive prospective ...

  15. Height Control and Deposition Measurement for the Electron Beam Free Form Fabrication (EBF3) Process

    Science.gov (United States)

    Seufzer, William J. (Inventor); Hafley, Robert A. (Inventor)

    2017-01-01

    A method of controlling a height of an electron beam gun and wire feeder during an electron freeform fabrication process includes utilizing a camera to generate an image of the molten pool of material. The image generated by the camera is utilized to determine a measured height of the electron beam gun relative to the surface of the molten pool. The method further includes ensuring that the measured height is within the range of acceptable heights of the electron beam gun relative to the surface of the molten pool. The present invention also provides for measuring a height of a solid metal deposit formed upon cooling of a molten pool. The height of a single point can be measured, or a plurality of points can be measured to provide 2D or 3D surface height measurements.

  16. Measuring orthometric water heights from lightweight Unmanned Aerial Vehicles (UAVs)

    Science.gov (United States)

    Bandini, Filippo; Olesen, Daniel; Jakobsen, Jakob; Reyna-Gutierrez, Jose Antonio; Bauer-Gottwein, Peter

    2016-04-01

    A better quantitative understanding of hydrologic processes requires better observations of hydrological variables, such as surface water area, water surface level, its slope and its temporal change. However, ground-based measurements of water heights are restricted to the in-situ measuring stations. Hence, the objective of remote sensing hydrology is to retrieve these hydraulic variables from spaceborne and airborne platforms. The forthcoming Surface Water and Ocean Topography (SWOT) satellite mission will be able to acquire water heights with an expected accuracy of 10 centimeters for rivers that are at least 100 m wide. Nevertheless, spaceborne missions will always face the limitations of: i) a low spatial resolution which makes it difficult to separate water from interfering surrounding areas and a tracking of the terrestrial water bodies not able to detect water heights in small rivers or lakes; ii) a limited temporal resolution which limits the ability to determine rapid temporal changes, especially during extremes. Unmanned Aerial Vehicles (UAVs) are one technology able to fill the gap between spaceborne and ground-based observations, ensuring 1) high spatial resolution; 2) tracking of the water bodies better than any satellite technology; 3) timing of the sampling which only depends on the operator 4) flexibility of the payload. Hence, this study focused on categorizing and testing sensors capable of measuring the range between the UAV and the water surface. The orthometric height of the water surface is then retrieved by subtracting the height above water measured by the sensors from the altitude above sea level retrieved by the onboard GPS. The following sensors were tested: a) a radar, b) a sonar c) a laser digital-camera based prototype developed at Technical University of Denmark. The tested sensors comply with the weight constraint of small UAVs (around 1.5 kg). The sensors were evaluated in terms of accuracy, maximum ranging distance and beam

  17. The Sine Method: An Alternative Height Measurement Technique

    Science.gov (United States)

    Don C. Bragg; Lee E. Frelich; Robert T. Leverett; Will Blozan; Dale J. Luthringer

    2011-01-01

    Height is one of the most important dimensions of trees, but few observers are fully aware of the consequences of the misapplication of conventional height measurement techniques. A new approach, the sine method, can improve height measurement by being less sensitive to the requirements of conventional techniques (similar triangles and the tangent method). We studied...

  18. Use of knee height as a surrogate measure of height in older South ...

    African Journals Online (AJOL)

    The study aimed to determine whether knee height would be a more appropriate surrogate measurement than armspan in determining height and body mass index (BMI) in a group of South African older people ( 60 years). A random sample of adults (older than 18 years) who attended selected clinics or who lived in ...

  19. Agreement between estimated and measured heights and weights ...

    African Journals Online (AJOL)

    index (BMI = kg/m2) and require accurate recording of a patient's height and weight.1. In reality, however, patients often cannot stand up straight for accurate height measurement, or are unable to step on a scale. In such cases, height and weight values are often obtained from the patient or their relatives, who either do not ...

  20. Measurement of step height by traceable interference microscope

    International Nuclear Information System (INIS)

    Chen, Y L; Wang, C Y

    2005-01-01

    A Traceable Interference Microscope (TIM) to calibrate the step height standards is presented. The construction of the TIM includes an interference microscope, a stabilized He-Ne laser, and a rotated ground glass. The instrument's original white light source is replaced by the stabilized laser through an optical fiber. The step height is measured by calculating the phase difference of two fringe patterns both on the upper and lower surfaces of the specimen. A new methodology called Double-Tilt Imaging (DTI) method is proposed to determine the Numerical Aperture Correction Factor (NACF). The wavelength of the light source and the difference both in angles and in spatial frequencies between the positive and negative tilts would reveal sufficient information to allow for the determination of the NACF directly. The light source used is a stabilized He-Ne laser traceable to the definition of the meter and the angle measurement to the angle standards by an autocollimator. The calculation of the aperture correction factor for the interference microscope with a 10x Mirau-type objective lens yields a traceable average value of 1.01936 with a relative standard uncertainty of about 5.74 x 10 -4 . The expanded uncertainty of this step height calibration system is determined to be approximately 3 nm

  1. Effect of inspiration/expiration on height measurement.

    Science.gov (United States)

    Kacer, Martina; Zhang, Guangxiang; Lane, Andrew H; Chen, John J; Wilson, Thomas A

    2008-08-01

    Growth parameters are a powerful screening tool in pediatric care. Accuracy assumes differing importance in different clinical settings. A small error is not clinically significant when height is obtained as a screening tool during annual well child visits. However, when assessing annual growth velocity using shorter interval visits, an error of equal magnitude might influence further management decisions. AIM AND HYPOTHESIS: To explore the effect of inspiration or expiration on height measurement. Our hypothesis was that height measurements obtained in inspiration would be greater than those obtained in expiration or without specific instructions as to status of respiration (unspecified). Heights of 99 individuals 8 years and older were measured in inspiration, expiration and unspecified respiratory status by two pediatric endocrinologists. Patients were measured three times in each mode. The p values were adjusted by Tukey procedure for multiple comparisons among three modes. Height measurement performed in inspiration, expiration or without specific instruction as to breathing (unspecified) did affect height measurement. Mean difference +/- SEM (95% CI) between height obtained in inspiration and expiration was 0.22 +/- 0.03 cm (95% CI: 0.15, 0.29); between inspiration and unspecified 0.31 +/- 0.04 cm (95% CI: 0.22, 0.40); and between expiration and unspecified 0.092 +/- 0.03 cm (95% CI: 0.03, 0.16). Based on these results, we recommend multiple height measurements using uniform technique including inspiratory/expiratory status, especially when calculating 'annualized' height velocity over short intervals.

  2. Degeneration and height of cervical discs classified from MRI compared with precise height measurements from radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Kolstad, Frode [National Centre of Spinal Disorders, Norwegian University of Science and Technology, University Hospital of Trondheim, 7006 Trondheim (Norway)]. E-mail: frode.kolstad@medisin.ntnu.no; Myhr, Gunnar [Department of Radiology, University Hospital of Trondheim, 7006 Trondheim (Norway); Kvistad, Kjell Arne [Department of Radiology, University Hospital of Trondheim, 7006 Trondheim (Norway); Nygaard, Oystein P. [National Centre of Spinal Disorders, Norwegian University of Science and Technology, University Hospital of Trondheim, 7006 Trondheim (Norway); Leivseth, Gunnar [Department of Neuromedicine, Faculty of Medicine, Norwegian University of Science and Technology, University Hospital of Trondheim, 7006 Trondheim (Norway)

    2005-09-01

    Study design: Descriptive study comparing MRI classifications with measurements from radiographs. Objectives: 1.Define the relationship between MRI classified cervical disc degeneration and objectively measured disc height. 2.Assess the level of inter- and intra-observer errors using MRI in defining cervical disc degeneration. Summary of background data: Cervical spine degeneration has been defined radiologically by loss of disc height, decreased disc and bone marrow signal intensity and disc protrusion/herniation on MRI. The intra- and inter-observer error using MRI in defining cervical degeneration influences data interpretation. Few previous studies have addressed this source of error. The relation and time sequence between cervical disc degeneration classified by MRI and cervical disc height decrease measured from radiographs is unclear. Methods: The MRI classification of degeneration was based on nucleus signal, prolaps identification and bone marrow signal. Two neuro-radiologists evaluated the MR-images independently in a blinded fashion. The radiographic disc height measurements were done by a new computer-assisted method compensating for image distortion and permitting comparison with normal level-, age- and gender-appropriate disc height. Results/conclusions: 1.Progressing disc degeneration classified from MRI is on average significantly associated with a decrease of disc height as measured from radiographs. Within each MRI defined category of degeneration measured disc heights, however, scatter in a wide range. 2.The inter-observer agreement between two neuro-radiologists in both defining degeneration and disc height by MRI was only moderate. Studies addressing questions related to cervical disc degeneration should take this into consideration.

  3. Degeneration and height of cervical discs classified from MRI compared with precise height measurements from radiographs

    International Nuclear Information System (INIS)

    Kolstad, Frode; Myhr, Gunnar; Kvistad, Kjell Arne; Nygaard, Oystein P.; Leivseth, Gunnar

    2005-01-01

    Study design: Descriptive study comparing MRI classifications with measurements from radiographs. Objectives: 1.Define the relationship between MRI classified cervical disc degeneration and objectively measured disc height. 2.Assess the level of inter- and intra-observer errors using MRI in defining cervical disc degeneration. Summary of background data: Cervical spine degeneration has been defined radiologically by loss of disc height, decreased disc and bone marrow signal intensity and disc protrusion/herniation on MRI. The intra- and inter-observer error using MRI in defining cervical degeneration influences data interpretation. Few previous studies have addressed this source of error. The relation and time sequence between cervical disc degeneration classified by MRI and cervical disc height decrease measured from radiographs is unclear. Methods: The MRI classification of degeneration was based on nucleus signal, prolaps identification and bone marrow signal. Two neuro-radiologists evaluated the MR-images independently in a blinded fashion. The radiographic disc height measurements were done by a new computer-assisted method compensating for image distortion and permitting comparison with normal level-, age- and gender-appropriate disc height. Results/conclusions: 1.Progressing disc degeneration classified from MRI is on average significantly associated with a decrease of disc height as measured from radiographs. Within each MRI defined category of degeneration measured disc heights, however, scatter in a wide range. 2.The inter-observer agreement between two neuro-radiologists in both defining degeneration and disc height by MRI was only moderate. Studies addressing questions related to cervical disc degeneration should take this into consideration

  4. The mean sea surface height and geoid along the Geosat subtrack from Bermuda to Cape Cod

    Science.gov (United States)

    Kelly, Kathryn A.; Joyce, Terrence M.; Schubert, David M.; Caruso, Michael J.

    1991-07-01

    Measurements of near-surface velocity and concurrent sea level along an ascending Geosat subtrack were used to estimate the mean sea surface height and the Earth's gravitational geoid. Velocity measurements were made on three traverses of a Geosat subtrack within 10 days, using an acoustic Doppler current profiler (ADCP). A small bias in the ADCP velocity was removed by considering a mass balance for two pairs of triangles for which expendable bathythermograph measurements were also made. Because of the large curvature of the Gulf Stream, the gradient wind balance was used to estimate the cross-track component of geostrophic velocity from the ADCP vectors; this component was then integrated to obtain the sea surface height profile. The mean sea surface height was estimated as the difference between the instantaneous sea surface height from ADCP and the Geosat residual sea level, with mesoscale errors reduced by low-pass filtering. The error estimates were divided into a bias, tilt, and mesoscale residual; the bias was ignored because profiles were only determined within a constant of integration. The calculated mean sea surface height estimate agreed with an independent estimate of the mean sea surface height from Geosat, obtained by modeling the Gulf Stream as a Gaussian jet, within the expected errors in the estimates: the tilt error was 0.10 m, and the mesoscale error was 0.044 m. To minimize mesoscale errors in the estimate, the alongtrack geoid estimate was computed as the difference between the mean sea level from the Geosat Exact Repeat Mission and an estimate of the mean sea surface height, rather than as the difference between instantaneous profiles of sea level and sea surface height. In the critical region near the Gulf Stream the estimated error reduction using this method was about 0.07 m. Differences between the geoid estimate and a gravimetric geoid were not within the expected errors: the rms mesoscale difference was 0.24 m rms.

  5. Boundary layer height estimation by sodar and sonic anemometer measurements

    International Nuclear Information System (INIS)

    Contini, D; Cava, D; Martano, P; Donateo, A; Grasso, F M

    2008-01-01

    In this paper an analysis of different methods for the calculation of the boundary layer height (BLH) using sodar and ultrasonic anemometer measurements is presented. All the methods used are based on single point surface measurements. In particular the automatic spectral routine developed for Remtech sodar is compared with the results obtained with the parameterization of the vertical velocity variance, with the calculation of a prognostic model and with a parameterization based on horizontal velocity spectra. Results indicate that in unstable conditions the different methods provide similar pattern, with BLH relatively low, even if the parameterization of the vertical velocity variance is affected by a large scatter that limits its efficiency in evaluating the BLH. In stable nocturnal conditions the performances of the Remtech routine are lower with respect to the ones in unstable conditions. The spectral method, applied to sodar or sonic anemometer data, seems to be the most promising in order to develop an efficient routine for BLH determination

  6. Sea Surface Height, Absolute, Aviso, 0.25 degrees, Global, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aviso Absolute Sea Surface Height is the Sea Surface Height Deviation plus the long term mean dynamic height. This is Science Quality data.

  7. Height estimations based on eye measurements throughout a gait cycle

    DEFF Research Database (Denmark)

    Yang, Sylvia X M; Larsen, Peter K; Alkjær, Tine

    2014-01-01

    (EH) measurement, on the other hand, is less prone to concealment. The purpose of the present study was to investigate: (1) how the eye height varies during the gait cycle, and (2) how the eye height changes with head position. The eyes were plotted manually in APAS for 16 test subjects during...

  8. Measuring Forest Height and Biomass from Space

    Science.gov (United States)

    Agueh, Temilola Elisabeth Fato

    2013-01-01

    Talk about doing earth science at NASA and how what we do is focus on the biosphere- that is the living portion of the earth.In particular, we are interested in looking at forests-quantifying deforestation, regrowth, change in general and helping develop new cutting-edge technologies and instruments to be able to measure these changes in land use, land cover and quality more accurately.

  9. Mixing height measurements from UHF wind profiling radar

    Energy Technology Data Exchange (ETDEWEB)

    Angevine, W.M.; Grimsdell, A.W. [CIRES, Univ. of Colorado, and NOAA Aeronomy Lab., Boulder, Colorado (United States)

    1997-10-01

    Mixing height in convective boundary layers can be detected by wind profiling radars (profilers) operating at or near 915 MHZ. We have made such measurements in a variety of settings including Alabama in 1992; Nova Scotia, Canada, during the North Atlantic Regional Experiment (NARE) 1993; Tennessee during the Southern Oxidant Study (SOS) 1994; near a 450 m tower in Wisconsin in 1995; and extensively in Illinois during the Flatland95, `96, and `97 experiments, as well as continuous operations at the Flatland Atmospheric Observatory. Profiler mixing height measurements, like all measurements, are subject to some limitations. The most important of these are due to rainfall, minimum height, and height resolution. Profilers are very sensitive to rain, which dominates the reflectivity and prevents the mixing height from being detected. Because the best height resolution is currently 60 m and the minimum height is 120-150 m AGL, the profiler is not suited for detecting mixing height in stable or nocturnal boundary layers. Problems may also arise in very dry or cold environments. (au) 12 refs.

  10. human pelvis height is associated with other pelvis measurements

    African Journals Online (AJOL)

    guyton2

    2015. Vol 4 (1): 457 – 465. 457 www.anatomyafrica.org. ORIGINAL COMMUNICATION. HUMAN PELVIS HEIGHT IS ASSOCIATED WITH OTHER PELVIS. MEASUREMENTS OF OBSTETRIC VALUE ..... Automobile Occupant Posture. International Congress and Exposition, Detroit, Michigan, SAE. Technical Paper Series.

  11. Distributions of freak wave heights measured in the North Sea

    International Nuclear Information System (INIS)

    Stansell, P.

    2004-01-01

    We present a statistical analysis of some of the largest waves occurring during 793 h of surface elevation measurements collected during 14 severe storms in the North Sea. This data contains 104 freak waves. It is found that the probability of occurrence of freak waves is only weekly dependent on the significant wave height, significant wave steepness and spectral bandwidth. The probability does show a slightly stronger dependency on the skew and kurtosis of the surface elevation data, but on removing the contribution to these measures from the presence of the freakwaves themselves, this dependency largely disappears. Distributions of extreme waves are modelled by fitting Generalised Pareto distributions, and extreme value distributions and return periods are given for freak waves in terms of the empirical fitted parameters. It is shown by comparison with these fits that both the Rayleigh distribution and the fit of Nerzic and Prevosto severely under-predict the probability of occurrence of extreme waves. For the most extreme freak wave in our data, the Rayleigh distribution over-predicts the return period by about 300 times when compared to the fitted model. (author)

  12. Effect of the plate surface characteristics and gap height on yield stresses of a magnetorheological fluid

    International Nuclear Information System (INIS)

    Jonkkari, I; Syrjala, S; Kostamo, E; Kostamo, J; Pietola, M

    2012-01-01

    Effects of the plate material, surface roughness and measuring gap height on static and dynamic yield stresses of a magnetorheological (MR) fluid were investigated with a commercial plate–plate magnetorheometer. Magnetic and non-magnetic plates with smooth (Ra ∼ 0.3 μm) and rough (Ra ∼ 10 μm) surface finishes were used. It was shown by Hall probe measurements and finite element simulations that the use of magnetic plates or higher gap heights increases the level of magnetic flux density and changes the shape of the radial flux density profile. The yield stress increase caused by these factors was determined and subtracted from the measured values in order to examine only the effect of the wall characteristics or the gap height. Roughening of the surfaces offered a significant increase in the yield stresses for non-magnetic plates. With magnetic plates the yield stresses were higher to start with, but roughening did not increase them further. A significant part of the difference in measured stresses between rough non-magnetic and magnetic plates was caused by changes in magnetic flux density rather than by better contact of the particles to the plate surfaces. In a similar manner, an increase in gap height from 0.25 to 1.00 mm can lead to over 20% increase in measured stresses due to changes in the flux density profile. When these changes were compensated the dynamic yield stresses generally remained independent of the gap height, even in the cases where it was obvious that the wall slip was present. This suggests that with MR fluids the wall slip cannot be reliably detected by comparison of flow curves measured at different gap heights. (paper)

  13. Measuring the height-to-height correlation function of corrugation in suspended graphene

    International Nuclear Information System (INIS)

    Kirilenko, D.A.; Brunkov, P.N.

    2016-01-01

    Nanocorrugation of 2D crystals is an important phenomenon since it affects their electronic and mechanical properties. The corrugation may have various sources; one of them is flexural phonons that, in particular, are responsible for the thermal conductivity of graphene. A study of corrugation of just the suspended graphene can reveal much of valuable information on the physics of this complicated phenomenon. At the same time, the suspended crystal nanorelief can hardly be measured directly because of high flexibility of the 2D crystal. Moreover, the relief portion related to rapid out-of-plane oscillations (flexural phonons) is also inaccessible by such measurements. Here we present a technique for measuring the Fourier components of the height–height correlation function H(q) of suspended graphene which includes the effect of flexural phonons. The technique is based on the analysis of electron diffraction patterns. The H(q) is measured in the range of wavevectors q≈0.4–4.5 nm −1 . At the upper limit of this range H(q) does follow the T/κq 4 law. So, we measured the value of suspended graphene bending rigidity κ=1.2±0.4 eV at ambient temperature T≈300 K. At intermediate wave vectors, H(q) follows a slightly weaker exponent than theoretically predicted q −3.15 but is closer to the results of the molecular dynamics simulation. At low wave vectors, the dependence becomes even weaker, which may be a sign of influence of charge carriers on the dynamics of undulations longer than 10 nm. The technique presented can be used for studying physics of flexural phonons in other 2D materials. - Highlights: • A technique for measuring free-standing 2D crystal corrugation is proposed. • The height-to-height correlation function of the suspended graphene corrugation is measured. • Various parameters of the intrinsic graphene properties are experimentally determined.

  14. Quantification of the lift height for magnetic force microscopy using 3D surface parameters

    International Nuclear Information System (INIS)

    Nenadovic, M.; Strbac, S.; Rakocevic, Z.

    2010-01-01

    In this work, the quantitative conditions for the lift height for imaging of the magnetic field using magnetic force microscopy (MFM) were optimized. A thin cobalt film deposited on a monocrystalline silicon (1 0 0) substrate with a thickness of 55 nm and a thin nickel film deposited on a glass with a thickness of 600 nm were used as samples. The topography of the surface was acquired by tapping mode atomic force microscopy (AFM), while MFM imaging was performed in the lift mode for various lift heights. It was determined that the sensitivity of the measurements was about 10% higher for images obtained at a scan angle of 90 o compared to a scan angle of 0 deg. Therefore, the three-dimensional surface texture parameters, i.e., average roughness, skewness, kurtosis and the bearing ratio, were determined in dependence on the lift height for a scan angle of 90 deg. The results of the analyses of the surface parameters showed that the influence of the substrate and its texture on the magnetic force image could be neglected for lift heights above 40 nm and that the upper lift height limit is 100 nm. It was determined that the optimal values of the lift heights were in the range from 60 to 80 nm, depending on the nature of the sample and on the type of the tip used.

  15. Comparison of mixing height parameterizations with profiles measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jaquier, A.; Stuebi, R.; Tercier, P. [Swiss Meteorological Inst., SMI - MeteoSwiss, Payerne (Switzerland)

    1997-10-01

    Different meteorological pre-processors for dispersion studies are available to derive the atmospheric boundary layer mixing height (MH). The analysis of their performances has been reviewed in the framework of the European COST Action 710. In this project, the computed mixing height values have been compared with data derived mostly from aero-logical sounding analysis and Sodar measurements. Since then, a new analysis of a low-tropospheric wind profiler (WP) data has been performed taking advantage of its high data sampling ({delta}t {approx} 30 sec.). The comparison between these recent results and aero-logical sounding, Sodar data, as well as to meteorological pre-processors calculations are reported for three periods of several days corresponding to different meteorological situations. In convective conditions, the pre-processors give reasonable level, the mixing height growing rate is in fair agreement with the measured one. In stable cloudy daytime conditions, the modeled mixing height does not correspond to any measured height. (LN)

  16. An antithetic variate to facilitate upper-stem height measurements for critical height sampling with importance sampling

    Science.gov (United States)

    Thomas B. Lynch; Jeffrey H. Gove

    2013-01-01

    Critical height sampling (CHS) estimates cubic volume per unit area by multiplying the sum of critical heights measured on trees tallied in a horizontal point sample (HPS) by the HPS basal area factor. One of the barriers to practical application of CHS is the fact that trees near the field location of the point-sampling sample point have critical heights that occur...

  17. Linear predictability: A sea surface height case study

    Science.gov (United States)

    Sonnewald, Maike; Wunsch, Carl; Heimbach, Patrick

    2017-04-01

    A benchmark of linear predictive skill of global sea surface height (SSH or η) is presented, complementing more complicated studies of η predictive skill. Twenty years of the ECCOv4 state estimate (1992-2012) are used, fitting ARMA(n,m) models where the order is chosen by the Akaike and Bayesian Information Criteria (AIC and BIC). The prediction on the basis of monthly detrended data shows skill generally of the order of a few months, with isolated regions of twelve months or more. With the trend, the predictive skill increases, particularly in the south Pacific. Annually averaged data are also used, although the time-series are too short to assess the variability. Including a linear trend as part of the signal results in some enhanced predictability.

  18. Surface characteristics, equipment height, and the occurrence and severity of playground injuries.

    Science.gov (United States)

    Laforest, S; Robitaille, Y; Lesage, D; Dorval, D

    2001-03-01

    To evaluate whether surface characteristics (absorption level (g-max), material) and the height of play equipment are related to the occurrence and severity of injuries from falls. During the summers of 1991 and 1995, conformity of play equipment to Canadian standards was assessed in a random sample (n = 102) of Montreal public playgrounds. Surface absorption (g-max) was tested using a Max Hic instrument and the height of equipment was measured. Concurrently, all injuries presenting at the emergency department of Montreal's two children's hospitals were recorded and parents were interviewed. Inspected equipment was implicated in 185 injuries. The g-max measurements (1995 only) were available for 110 of these playground accidents. One third of falls (35 %) occurred on a surface exceeding 200 g and the risk of injury was three times greater than for g level lower than 150 (95% confidence interval (CI) 1.45 to 6.35). On surfaces having absorption levels between 150 g and 200 g, injuries were 1.8 times more likely (95% CI 0.91 to 3.57). Injuries were 2.56 times more likely to occur on equipment higher than 2 m compared with equipment lower than 1.5 m. Analysis of risk factors by severity of injury failed to show any positive relationships between the g-max or height and severity, whereas surface material was a good predictor of severity. This study confirms the relationships between risk of injury, surface resilience, and height of equipment, as well as between type of material and severity of injury. Our data suggest that acceptable limits for surface resilience be set at less than 200 g, and perhaps even less than 150 g, and not exceed 2 m for equipment height. These findings reinforce the importance of installing recommended materials, such as sand, beneath play equipment.

  19. Cloud heights measured by MISR from 2000 to 2015

    Science.gov (United States)

    Davies, Roger; Jovanovic, Veljko M.; Moroney, Catherine M.

    2017-04-01

    Davies and Molloy (2012) reported a decrease in the global effective cloud height over the first 10 years of Multiangle Imaging Spectroradiometer (MISR) measurements on the Terra satellite. We have reexamined their time series for possible artefacts that might especially affect the initial portion of the record when the heights appeared anomalously high. While variations in sampling were shown to be inconsequential, an artefact due to the change in equator crossing time that affected the first 2 years was discovered, and this has now been corrected. That correction, together with the extension of the time series by five more years, yields no significant overall trend in global heights during the first 15 years of Terra operation. The time series is dominated by large interannual fluctuations associated with La Niña events that mask any overall trend on a global scale. On a regional basis, the cloud heights showed significant interannual variations of much larger amplitude, sometimes with fairly direct cancellation between regions. There were unexplained differences between the two hemispheres in the timing of height anomalies. These differences persisted over a large range of extratropical latitudes, suggestive of teleconnections. Within the tropics, there were very strong changes associated with the Central Pacific and Indonesian Maritime Continent regions that oscillated out of phase with each other, with interannual amplitudes that exceeded 1 km.

  20. SOME ASPECTS IN HEIGHT MEASUREMENT BY UAV PHOTOGRAMMETRY

    Directory of Open Access Journals (Sweden)

    R. Matsuoka

    2013-08-01

    Full Text Available We conducted an experiment to investigate the feasibility of the deformation measurement of a large-scale solar power plant on reclaimed land by UAV photogrammetry. Two teams engaged in the experiment at first. One, which is called Team-A, carried out orientation of images following the procedure of conventional aerial photogrammetry. The other, which is called Team-C, executed that in the manner of close range photogrammetry. The RMSE in height measurement by Team-A was 121.5 mm, while that by Team-C was 8.7 mm. This paper reports an analysis conducted in order to investigate the cause of the large difference in height measurement accuracy between Team-A and Team-C. In the analysis the third team, which is called Team-S, conducts supplementary orientation by using the images utilized by Team-A in the same manner as Team-C did. The RMSE in height measurement by Team-S is 19.1 mm. Our investigation focuses on the difference of the arrangement of points utilized in the orientation. Team-A selected pass points and tie points on image automatically by Intergraph’s ImageStation Automatic Triangulation (ISAT software, while Team-C and Team-S selected points to be utilized in orientation manually so that selected points are distributed uniformly in the experiment area. From the results of the analysis we conclude that the sets of tie points along a straight line on a plane that were selected automatically by the ISAT would bring the low accuracy in height measurement by Team-A.

  1. Shearing interference microscope for step-height measurements.

    Science.gov (United States)

    Trịnh, Hưng-Xuân; Lin, Shyh-Tsong; Chen, Liang-Chia; Yeh, Sheng-Lih; Chen, Chin-Sheng; Hoang, Hong-Hai

    2017-05-01

    A shearing interference microscope using a Savart prism as the shear plate is proposed for inspecting step-heights. Where the light beam propagates through the Savart prism and microscopic system to illuminate the sample, it then turns back to re-pass through the Savart prism and microscopic system to generate a shearing interference pattern on the camera. Two measurement modes, phase-shifting and phase-scanning, can be utilized to determine the depths of the step-heights on the sample. The first mode, which employs a narrowband source, is based on the five-step phase-shifting algorithm and has a measurement range of a quarter-wavelength. The second mode, which adopts a broadband source, is based on peak-intensity identification technology and has a measurement range up to a few micrometres. This paper is to introduce the configuration and measurement theory of this microscope, perform a setup used to implement it, and present the experimental results from the uses of the setup. The results not only verify the validity but also confirm the high measurement repeatability of the proposed microscope. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  2. Stereoscopic Roadside Curb Height Measurement using V-Disparity

    DEFF Research Database (Denmark)

    Matu, Florin-Octavian; Vlaykov, Iskren; Thøgersen, Mikkel

    2014-01-01

    Managing road assets, such as roadside curbs, is one of the interests of municipalities. As an interesting application of computer vision, this paper proposes a system for automated measurement of the height of the roadside curbs. The developed system uses the spatial information available...... in the disparity image obtained from a stereo setup. Data about the geometry of the scene is extracted in the form of a row-wise histogram of the disparity map. From parameterizing the two strongest lines, each pixel can be labeled as belonging to one plane, either ground, sidewalk or curb candidates. Experimental...

  3. On the hysteresis of the sea surface and its applicability to wave height predictions

    Science.gov (United States)

    Parsons, C. L.

    1977-01-01

    Because of the low dissipation rate of wave energy on the ocean's surface, the wave height at some location and time must be dependent upon wind fields in existence there at previous times and upon swell propagated there from other regions. To study these relationships, significant wave height (SWH) measurements from the Geos-3 radar altimeter are used in conjunction with anemometer windspeed measurements from weather ships, L, C, and R. During the passage of large cyclonic disturbances near the fixed locations of these vessels in the North Atlantic in February 1976, distinct hysteresis profiles that characterize the sea's memory during generation and dissipation conditions are observed. Examples are given that demonstrate the influences of cyclone intensity, movement, velocity, and shape on the configuration of these profiles.

  4. Forest Canopy Height Estimation from Calipso Lidar Measurement

    Directory of Open Access Journals (Sweden)

    Lu Xiaomei

    2016-01-01

    Canopy penetration depths at two wavelengths indicate moderately strong relationships for estimating the canopy height. Results show that the CALIOP-derived canopy heights were highly correlated with the ICESat/GLAS-derived values with a mean RMSE of 3.4 m and correlation coefficient (R of 0.89. Our findings present a relationship between the penetration difference and canopy height, which can be used as another metrics for canopy height estimation, except the full waveforms.

  5. Measurements of the ionization heights of sporadic radio-meteors

    International Nuclear Information System (INIS)

    Baggaley, W.J.; Webb, T.H.

    1980-01-01

    The echo heights and echo point ionization densities of 4587 sporadic radio-meteors have been determined using a calibrated interferometric height-finding system. Over the height interval 92 to 96 km no association was found between height and ionization but, for radio-meteors ablating above and below this region, significant and opposite trends exist in the data. It is suggested that this could be evidence for the influx of two distinct meteoroid populations. (author)

  6. Gridded 5-day mean sea surface height anomaly and significant wave height from Jason-1 and OSTM/Jason-2 satellites (NODC Accession 0065055)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains the gridded 5-day mean sea surface height anomaly (SSHA) and Ku Band significant wave height (SWH-KU) observed from Jason-1 and OSTM/Jason-2...

  7. A Study on the Relationships among Surface Variables to Adjust the Height of Surface Temperature for Data Assimilation.

    Science.gov (United States)

    Kang, J. H.; Song, H. J.; Han, H. J.; Ha, J. H.

    2016-12-01

    The observation processing system, KPOP (KIAPS - Korea Institute of Atmospheric Prediction Systems - Package for Observation Processing) have developed to provide optimal observations to the data assimilation system for the KIAPS Integrated Model (KIM). Currently, the KPOP has capable of processing almost all of observations for the KMA (Korea Meteorological Administration) operational global data assimilation system. The height adjustment of SURFACE observations are essential for the quality control due to the difference in height between observation station and model topography. For the SURFACE observation, it is usual to adjust the height using lapse rate or hypsometric equation, which decides values mainly depending on the difference of height. We have a question of whether the height can be properly adjusted following to the linear or exponential relationship solely with regard to the difference of height, with disregard the atmospheric conditions. In this study, firstly we analyse the change of surface variables such as temperature (T2m), pressure (Psfc), humidity (RH2m and Q2m), and wind components (U and V) according to the height difference. Additionally, we look further into the relationships among surface variables . The difference of pressure shows a strong linear relationship with difference of height. But the difference of temperature according to the height shows a significant correlation with difference of relative humidity than with the height difference. A development of reliable model for the height-adjustment of surface temperature is being undertaken based on the preliminary results.

  8. A prospective study of measured body size and height and risk of keratinocyte cancers and melanoma.

    Science.gov (United States)

    Lahmann, Petra H; Hughes, Maria Celia B; Williams, Gail M; Green, Adèle C

    2016-02-01

    The potential influence of measured body weight and height on keratinocyte skin cancer risk has scarcely been studied. Some evidence indicates melanoma risk increases as self-reported height increases, but an association with body mass index (BMI) is less certain. We measured body weight and height of 1171 Australian men and women in a community-based skin cancer study in Queensland and prospectively examined the association of BMI, body surface area (BSA) and height and incidence of basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma while accounting for skin phenotype, sun exposure, clinical/cutaneous signs of chronic photodamage and other risk factors. During 16 years of follow-up, 334 and 188 participants newly developed BCC and SCC, respectively; 28 participants were diagnosed with primary melanoma. BMI and BSA were unrelated to skin cancer incidence. After full adjustment, height was significantly associated with SCC development in men (relative risk (RR)=1.66; 95% confidence interval (CI)=1.11-2.48, for ≥175cm vs ≤171cm, Ptrend=0.017), and BCC in women (Ptrend=0.043). Melanoma in men, was similarly positively associated with height (RR per 5cm increment=1.55; 95%CI 0.97-2.47, P=0.067) though not significantly. This study shows that after adjusting for sun exposure tall stature may be a risk factor for the most common types of skin cancer BCC, SCC, and melanoma, while body mass and surface area appear unrelated to risk. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Step-height standards based on the rapid formation of monolayer steps on the surface of layered crystals

    Energy Technology Data Exchange (ETDEWEB)

    Komonov, A.I. [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences (ISP SBRAS), pr. Lavrentieva 13, Novosibirsk 630090 (Russian Federation); Prinz, V.Ya., E-mail: prinz@isp.nsc.ru [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences (ISP SBRAS), pr. Lavrentieva 13, Novosibirsk 630090 (Russian Federation); Seleznev, V.A. [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences (ISP SBRAS), pr. Lavrentieva 13, Novosibirsk 630090 (Russian Federation); Kokh, K.A. [Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences (IGM SB RAS), pr. Koptyuga 3, Novosibirsk 630090 (Russian Federation); Shlegel, V.N. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences (NIIC SB RAS), pr. Lavrentieva 3, Novosibirsk 630090 (Russian Federation)

    2017-07-15

    Highlights: • Easily reproducible step-height standard for SPM calibrations was proposed. • Step-height standard is monolayer steps on the surface of layered single crystal. • Long-term change in surface morphology of Bi{sub 2}Se{sub 3} and ZnWO{sub 4} was investigated. • Conducting surface of Bi{sub 2}Se{sub 3} crystals appropriate for calibrating STM. • Ability of robust SPM calibrations under ambient conditions were demonstrated. - Abstract: Metrology is essential for nanotechnology, especially for structures and devices with feature sizes going down to nm. Scanning probe microscopes (SPMs) permits measurement of nanometer- and subnanometer-scale objects. Accuracy of size measurements performed using SPMs is largely defined by the accuracy of used calibration measures. In the present publication, we demonstrate that height standards of monolayer step (∼1 and ∼0.6 nm) can be easily prepared by cleaving Bi{sub 2}Se{sub 3} and ZnWO{sub 4} layered single crystals. It was shown that the conducting surface of Bi{sub 2}Se{sub 3} crystals offers height standard appropriate for calibrating STMs and for testing conductive SPM probes. Our AFM study of the morphology of freshly cleaved (0001) Bi{sub 2}Se{sub 3} surfaces proved that such surfaces remained atomically smooth during a period of at least half a year. The (010) surfaces of ZnWO{sub 4} crystals remained atomically smooth during one day, but already two days later an additional nanorelief of amplitude ∼0.3 nm appeared on those surfaces. This relief, however, did not further grow in height, and it did not hamper the calibration. Simplicity and the possibility of rapid fabrication of the step-height standards, as well as their high stability, make these standards available for a great, permanently growing number of users involved in 3D printing activities.

  10. Does Heel Height Cause Imbalance during Sit-to-Stand Task: Surface EMG Perspective

    Directory of Open Access Journals (Sweden)

    Ganesh R. Naik

    2017-08-01

    Full Text Available The purpose of this study was to determine whether electromyography (EMG muscle activities around the knee differ during sit-to-stand (STS and returning task for females wearing shoes with different heel heights. Sixteen healthy young women (age = 25.2 ± 3.9 years, body mass index = 20.8 ± 2.7 kg/m2 participated in this study. Electromyography signals were recorded from the two muscles, vastus medialis (VM and vastus lateralis (VL that involve in the extension of knee. The participants wore shoes with five different heights, including 4, 6, 8, 10, and 12 cm. Surface electromyography (sEMG data were acquired during STS and stand-to-sit-returning (STSR tasks. The data was filtered using a fourth order Butterworth (band pass filter of 20–450 Hz frequency range. For each heel height, we extracted median frequency (MDF and root mean square (RMS features to measure sEMG activities between VM and VL muscles. The experimental results (based on MDF and RMS-values indicated that there is imbalance between vasti muscles for more elevated heels. The results are also quantified with statistical measures. The study findings suggest that there would be an increased likelihood of knee imbalance and fatigue with regular usage of high heel shoes (HHS in women.

  11. Parametric fitting of corneal height data to a biconic surface.

    Science.gov (United States)

    Janunts, Edgar; Kannengießer, Marc; Langenbucher, Achim

    2015-03-01

    As the average corneal shape can effectively be approximated by a conic section, a determination of the corneal shape by biconic parameters is desired. The purpose of the paper is to introduce a straightforward mathematical approach for extracting clinically relevant parameters of corneal surface, such as radii of curvature and conic constants for principle meridians and astigmatism. A general description for modeling the ocular surfaces in a biconic form is given, based on which an implicit parametric surface fitting algorithm is introduced. The solution of the biconic fitting is obtained by a two sequential least squares optimization approach with constrains. The data input can be raw information from any corneal topographer with not necessarily a uniform data distribution. Various simulated and clinical data are studied including surfaces with rotationally symmetric and non-symmetric geometries. The clinical data was obtained from the Pentacam (Oculus) for the patient having undergone a refractive surgery. A sub-micrometer fitting accuracy was obtained for all simulated surfaces: 0,08 μm RMS fitting error at max for rotationally symmetric and 0,125 μm for non-symmetric surfaces. The astigmatism was recovered in a sub-minutes resolution. The equality in rotational symmetric and the superiority in non-symmetric surfaces of the presented model over the widely used quadric fitting model is shown. The introduced biconic surface fitting algorithm is able to recover the apical radii of curvature and conic constants in principle meridians. This methodology could be a platform for advanced IOL calculations and enhanced contact lens fitting. Copyright © 2014. Published by Elsevier GmbH.

  12. A next generation altimeter for mapping the sea surface height variability: opportunities and challenges

    Science.gov (United States)

    Fu, Lee-Lueng; Morrow, Rosemary

    2016-07-01

    The global observations of the sea surface height (SSH) have revolutionized oceanography since the beginning of precision radar altimetry in the early 1990s. For the first time we have continuous records of SSH with spatial and temporal sampling for detecting the global mean sea level rise, the waxing and waning of El Niño, and the ocean circulation from gyres to ocean eddies. The limit of spatial resolution of the present constellation of radar altimeters in mapping SSH variability is approaching 100 km (in wavelength) with 3 or more simultaneous altimetric satellites in orbit. At scales shorter than 100 km, the circulation contains substantial amount of kinetic energy in currents, eddies and fronts that are responsible for the stirring and mixing of the ocean, especially from the vertical exchange of the upper ocean with the deep. A mission currently in development will use the technique of radar interferometry for making high-resolution measurement of the height of water over the ocean as well as on land. It is called Surface Water and Ocean Topography (SWOT), which is a joint mission of US NASA and French CNES, with contributions from Canada and UK. SWOT promises the detection of SSH at scales approaching 15 km, depending on the sea state. SWOT will make SSH measurement over a swath of 120 km with a nadir gap of 20 km in a 21-day repeat orbit. A conventional radar altimeter will provide measurement along the nadir. This is an exploratory mission with applications in oceanography and hydrology. The increased spatial resolution offers an opportunity to study ocean surface processes to address important questions about the ocean circulation. However, the limited temporal sampling poses challenges to map the evolution of the ocean variability that changes rapidly at the small scales. The measurement technique and the development of the mission will be presented with emphasis on its science program with outlook on the opportunities and challenges.

  13. Surface cleanliness measurement procedure

    Science.gov (United States)

    Schroder, Mark Stewart; Woodmansee, Donald Ernest; Beadie, Douglas Frank

    2002-01-01

    A procedure and tools for quantifying surface cleanliness are described. Cleanliness of a target surface is quantified by wiping a prescribed area of the surface with a flexible, bright white cloth swatch, preferably mounted on a special tool. The cloth picks up a substantial amount of any particulate surface contamination. The amount of contamination is determined by measuring the reflectivity loss of the cloth before and after wiping on the contaminated system and comparing that loss to a previous calibration with similar contamination. In the alternative, a visual comparison of the contaminated cloth to a contamination key provides an indication of the surface cleanliness.

  14. Absolute Height of Sea Surface by Trajectory of GPS Antennae Over Submerged Pressure Gauges

    Science.gov (United States)

    Bouin, M.; Calmant, S.; Cheng, K.; Ballu, V.; Shum, C. K.; Testut, L.

    2003-12-01

    Water height data provided by seafloor tide gauges is a combination of sea-level variations and ground motion. Both of these signals are of scientific interest, but they must be separated in order to be useful. Estimating ground motion is specially important in very tectonically active areas such as the Pacific Ocean rim. One promising method to separate the two contributions is to use satellite altimetry data which gives absolute water height, but these data must be calibrated using ground truth measurements. Once different components of the signal are separated, bottom pressure gauges can be used to detect vertical movements of the seafloor such as co-seismic or slow inter-seismic motions. The Vanuatu archipelago is part of the Pacific ring of fire, where plates are rapidly converging. In the area, movements are very rapid and the seismic activity is intense, which gives a good opportunity to study deformation and seismic cycle. To get an integrate picture of vertical deformation over one plate and between the two plates, one needs to be able to monitor vertical movements on both underwater and emerged areas. We conducted an experiment in the Vanuatu archipelago, South-West Pacific, to compare measurements from bottom pressure gauges located beneath altimetry satellite tracks with sea surface altitude measurements from GPS. Two bottom pressure gauges are immerged since Nov. 1999 on Sabine bank (15.90° S, 166.14° E) and Wusi Bank (15.34° S, 166.55° E), West of Santo island, Vanuatu. In order to perform absolute calibrations of JASON and ENVISAT altimeters that overfly the Wusi and Sabine banks, respectively, we performed GPS measurements of instantaneous sea surface altitude. The GPS antennae were fixed on top of the 30m long R/V Alis. An inertial unit also recorded the high frequency vessel motions. The height of the antennae over the sea surface was measured using a laser distancemeter in calibration sessions during particularly calm sea states. We present

  15. Intrapartum symphysio-fundal height measurement as a predictor of ...

    African Journals Online (AJOL)

    Background: Low birth weight (LBW) increases the risk of perinatal morbidity and mortality and of the long term neurologic and developmental disorders. Early identification of LBW is necessary to decrease complications and enhance the survival of the newborn. Aim: To determine the usefulness of symphysio-fundal height ...

  16. Validation of an inertial measurement unit for the measurement of jump count and height.

    Science.gov (United States)

    MacDonald, Kerry; Bahr, Roald; Baltich, Jennifer; Whittaker, Jackie L; Meeuwisse, Willem H

    2017-05-01

    To validate the use of an inertial measurement unit (IMU) for the collection of total jump count and assess the validity of an IMU for the measurement of jump height against 3-D motion analysis. Cross sectional validation study. 3D motion-capture laboratory and field based settings. Thirteen elite adolescent volleyball players. Participants performed structured drills, played a 4 set volleyball match and performed twelve counter movement jumps. Jump counts from structured drills and match play were validated against visual count from recorded video. Jump height during the counter movement jumps was validated against concurrent 3-D motion-capture data. The IMU device captured more total jumps (1032) than visual inspection (977) during match play. During structured practice, device jump count sensitivity was strong (96.8%) while specificity was perfect (100%). The IMU underestimated jump height compared to 3D motion-capture with mean differences for maximal and submaximal jumps of 2.5 cm (95%CI: 1.3 to 3.8) and 4.1 cm (3.1-5.1), respectively. The IMU offers a valid measuring tool for jump count. Although the IMU underestimates maximal and submaximal jump height, our findings demonstrate its practical utility for field-based measurement of jump load. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Arch height index normative values of college-aged women using the arch height index measurement system.

    Science.gov (United States)

    Weimar, Wendi H; Shroyer, Justin F

    2013-01-01

    The arch height index measurement system (AHIMS) device has been found to be a reliable and valid instrument for measuring the arch height index (AHI) of the feet of individuals; however, normative data for the AHI are lacking for various populations. Therefore, the purposes of this study were to establish population normative AHI values for college-aged females and to compare the observed AHI data across right and left feet. Seventy-nine college-aged females served as study participants, and both feet were measured using the AHIMS in the seated and standing positions. The AHI was calculated as the ratio of the dorsum height of the foot at half the total foot length to the length of the foot from the heel to the base of the first metatarsophalangeal joint. The mean ± SD AHI values for the left and right feet in the seated position were 0.355 ± 0.031 and 0.369 ± 0.034, respectively. The mean ± SD AHI values for the left and right feet in the standing position were 0.338 ± 0.031 and 0.343 ± 0.033, respectively. There were significant differences observed between the left and right feet for the seated (P feet of the participants sampled. Although normative values were obtained, we caution against using these values to classify foot arch types based solely on a sample of the population studied.

  18. Measurement of width and step-height of photolithographic product patterns by using digital holography

    International Nuclear Information System (INIS)

    Shin, Ju Yeop; Kang, Sung Hoon; Ma, Hye Joon; Jung, Hyun Chul; Hong, Chung Ki; Kim, Kyeong Suk; Kwon, Ik Hwan; Yang, Seung Pil

    2016-01-01

    The semiconductor industry is one of the key industries of Korea, which has continued growing at a steady annual growth rate. Important technology for the semiconductor industry is high integration of devices. This is to increase the memory capacity for unit area, of which key is photolithography. The photolithography refers to a technique for printing the shadow of light lit on the mask surface on to wafer, which is the most important process in a semiconductor manufacturing process. In this study, the width and step-height of wafers patterned through this process were measured to ensure uniformity. The widths and inter-plate heights of the specimens patterned using photolithography were measured using transmissive digital holography. A transmissive digital holographic interferometer was configured, and nine arbitrary points were set on the specimens as measured points. The measurement of each point was compared with the measurements performed using a commercial device called scanning electron microscope (SEM) and Alpha Step. Transmission digital holography requires a short measurement time, which is an advantage compared to other techniques. Furthermore, it uses magnification lenses, allowing the flexibility of changing between high and low magnifications. The test results confirmed that transmissive digital holography is a useful technique for measuring patterns printed using photolithography

  19. The impact of variable building height on drag, flow and turbulence over a realistic suburban surface

    Science.gov (United States)

    Giometto, M. G.; Christen, A.; Calaf, M.; Parlange, M. B.

    2014-12-01

    In urban environments, where buildings have variable configurations and heights, the tallest structures have a disproportional impact on drag, mean flow and turbulence. Although wind-engineering studies document well the effects of individual high-rise buildings on the immediate surrounding, the impact of varying building heights on the larger horizontally averaged flow has not been quantified systematically for realistic urban configurations. We use Large Eddy Simulation (LES) as a means to study the fully developed turbulent flow over and within a 512 x 512 m2 subset of the true urban geometry in the city of Basel, Switzerland. A periodic LES domain is centered on the location of a tower, where measurements of turbulence were performed in 2001/02, which allows a direct validation of the LES at a specific location in the domain. The Lagrangian scale-dependent LES model is adopted to parametrize the subgrid stresses in the bulk of the flow and buildings are taken into account adopting a discrete-forcing-approach immersed boundary method (IBM), with the geometry taken from a highly accurate digital building model. A series of high-resolution LES runs are performed for various directions of the approaching flow, and with all buildings included and then buildings above a certain height threshold progressively removed, to isolate the impact of tall structures. Results show how the presence of isolated tall buildings strongly modifies the roughness properties of the entire urban roughness sublayer, causing an increase in resolved pressure forces, which contributes to the overall surface induced drag. In the presence of tall buildings the local structure of the roughness sublayer is partitioned into two regimes: fine scale wake turbulence and elongated, high speed streak-like motions, locked between the position of isolated structures, with their axis aligned in the stream wise direction. For arrays with differing building heights statistics significantly differ from

  20. Direct derivation of maize plant and crop height from low-cost time-of-flight camera measurements.

    Science.gov (United States)

    Hämmerle, Martin; Höfle, Bernhard

    2016-01-01

    In agriculture, information about the spatial distribution of crop height is valuable for applications such as biomass and yield estimation, or increasing field work efficiency in terms of fertilizing, applying pesticides, irrigation, etc. Established methods for capturing crop height often comprise restrictions in terms of cost and time efficiency, flexibility, and temporal and spatial resolution of measurements. Furthermore, crop height is mostly derived from a measurement of the bare terrain prior to plant growth and measurements of the crop surface when plants are growing, resulting in the need of multiple field campaigns. In our study, we examine a method to derive crop heights directly from data of a plot of full grown maize plants captured in a single field campaign. We assess continuous raster crop height models (CHMs) and individual plant heights derived from data collected with the low-cost 3D camera Microsoft ® Kinect ® for Xbox One™ based on a comprehensive comparison to terrestrial laser scanning (TLS) reference data. We examine single measurements captured with the 3D camera and a combination of the single measurements, i.e. a combination of multiple perspectives. The quality of both CHMs, and individual plant heights is improved by combining the measurements. R 2 of CHMs derived from single measurements range from 0.48 to 0.88, combining all measurements leads to an R 2 of 0.89. In case of individual plant heights, an R 2 of 0.98 is achieved for the combined measures (with R 2  = 0.44 for the single measurements). The crop heights derived from the 3D camera measurements comprise an average underestimation of 0.06 m compared to TLS reference values. We recommend the combination of multiple low-cost 3D camera measurements, removal of measurement artefacts, and the inclusion of correction functions to improve the quality of crop height measurements. Operating low-cost 3D cameras under field conditions on agricultural machines or on autonomous

  1. Multimodel simulations of Arctic Ocean sea surface height variability in the period 1970-2009

    DEFF Research Database (Denmark)

    Koldunov, Nikolay V.; Serra, Nuno; Koehl, Armin

    2014-01-01

    is in reasonable agreement with available measurements. Focusing on results from one of the models for a detailed analysis, it is shown that the decadal-scale SSH variability over shelf areas and deep parts of the Arctic Ocean have pronounced differences that are determined mostly by salinity variations. A further......The performance of several numerical ocean models is assessed with respect to their simulation of sea surface height (SSH) in the Arctic Ocean, and the main patterns of SSH variability and their causes over the past 40 years (1970-2009) are analyzed. In comparison to observations, all tested models...... of low-salinity shelf water. Overall, we show that present-day models can be used for investigating the reasons for low-frequency SSH variability in the region....

  2. Automatic rice crop height measurement using a field server and digital image processing.

    Science.gov (United States)

    Sritarapipat, Tanakorn; Rakwatin, Preesan; Kasetkasem, Teerasit

    2014-01-07

    Rice crop height is an important agronomic trait linked to plant type and yield potential. This research developed an automatic image processing technique to detect rice crop height based on images taken by a digital camera attached to a field server. The camera acquires rice paddy images daily at a consistent time of day. The images include the rice plants and a marker bar used to provide a height reference. The rice crop height can be indirectly measured from the images by measuring the height of the marker bar compared to the height of the initial marker bar. Four digital image processing steps are employed to automatically measure the rice crop height: band selection, filtering, thresholding, and height measurement. Band selection is used to remove redundant features. Filtering extracts significant features of the marker bar. The thresholding method is applied to separate objects and boundaries of the marker bar versus other areas. The marker bar is detected and compared with the initial marker bar to measure the rice crop height. Our experiment used a field server with a digital camera to continuously monitor a rice field located in Suphanburi Province, Thailand. The experimental results show that the proposed method measures rice crop height effectively, with no human intervention required.

  3. Automatic Rice Crop Height Measurement Using a Field Server and Digital Image Processing

    Science.gov (United States)

    Sritarapipat, Tanakorn; Rakwatin, Preesan; Kasetkasem, Teerasit

    2014-01-01

    Rice crop height is an important agronomic trait linked to plant type and yield potential. This research developed an automatic image processing technique to detect rice crop height based on images taken by a digital camera attached to a field server. The camera acquires rice paddy images daily at a consistent time of day. The images include the rice plants and a marker bar used to provide a height reference. The rice crop height can be indirectly measured from the images by measuring the height of the marker bar compared to the height of the initial marker bar. Four digital image processing steps are employed to automatically measure the rice crop height: band selection, filtering, thresholding, and height measurement. Band selection is used to remove redundant features. Filtering extracts significant features of the marker bar. The thresholding method is applied to separate objects and boundaries of the marker bar versus other areas. The marker bar is detected and compared with the initial marker bar to measure the rice crop height. Our experiment used a field server with a digital camera to continuously monitor a rice field located in Suphanburi Province, Thailand. The experimental results show that the proposed method measures rice crop height effectively, with no human intervention required. PMID:24451465

  4. Measuring the fill height of sealed cans with a compound pendulum

    Energy Technology Data Exchange (ETDEWEB)

    Rinard, P.M.

    1995-06-01

    A compound pendulum has been designed, fabricated, tested, and used to determine the fill height of material in sealed cans. The specific cans that stimulated this work are partially filled with uranium and plutonium oxide. Fill height affects nondestructive assays using fission neutrons, but corrections for various fill heights can be made once the height is known. Heights vary with use as the powder compacts or loosens, so it is necessary to determine the height at the time of the neutron measurement. The pendulum is small and readily portable so it can be taken to the location of the neutron measurement. Tests with open cans filled with sand to various known heights had accuracies generally within 3%. Factors that can affect the accuracy are examined and discussed. Experience in using the pendulum on sealed cans is related.

  5. A rigorous assessment of tree height measurements obtained using airborne LIDAR and conventional field methods.

    Science.gov (United States)

    Hans-Erik Andersen; Stephen E. Reutebuch; Robert J. McGaughey

    2006-01-01

    Tree height is an important variable in forest inventory programs but is typically time-consuming and costly to measure in the field using conventional techniques. Airborne light detection and ranging (LIDAR) provides individual tree height measurements that are highly correlated with field-derived measurements, but the imprecision of conventional field techniques does...

  6. Pulse height measurements and electron attachment in drift chambers operated with Xe,CO2 mixtures

    CERN Document Server

    Andronic, A

    2003-01-01

    We present pulse height measurements in drift chambers operated with Xe,CO2 gas mixtures. We investigate the attachment of primary electrons on oxygen and SF6 contaminants in the detection gas. The measurements are compared with simulations of properties of drifting electrons. We present two methods to check the gas quality: gas chromatography and Fe55 pulse height measurements using monitor detectors.

  7. Physical Retracking of Jason-1 LRM data for ocean surface height/gravity field determination

    Science.gov (United States)

    Jain, Maulik; Baltazar Andersen, Ole; Stenseng, Lars; Dall, Jørgen

    2013-04-01

    Jason-1 Low Resolution Mode (LRM) waveforms can be processed to extract accurate heights of the ocean surface. These heights are adjusted taking into account various corrections available. Further the along surface slope/variation of these ocean heights can be used to make an estimation of the gravity field. An important part of this gravity field estimation is dependent on the way the LRM waveform is processed. Thus a physical model based on an error function is used, and the LRM waveforms are fit to this model. A processing system made up of 2 parameter and 3 parameter fitting models are used in order to extract the most reliable ocean surface heights. The quality of the processing system is judged by evaluating the standard deviation of the sea surface anomaly obtained after all corrections and the mean sea surface/geoid are removed. The lower the value of the standard deviation of the sea surface anomaly, the better the quality of processing is. Hence, different processing schemes are considered and evaluated in order to conclude towards the best retracking procedure which would eventually result in high accuracy gravity field estimations.

  8. An atlas of monthly mean distributions of GEOSAT sea surface height, SSMI surface wind speed, AVHRR/2 sea surface temperature, and ECMWF surface wind components during 1988

    Science.gov (United States)

    Halpern, D.; Zlotnicki, V.; Newman, J.; Brown, O.; Wentz, F.

    1991-01-01

    Monthly mean global distributions for 1988 are presented with a common color scale and geographical map. Distributions are included for sea surface height variation estimated from GEOSAT; surface wind speed estimated from the Special Sensor Microwave Imager on the Defense Meteorological Satellite Program spacecraft; sea surface temperature estimated from the Advanced Very High Resolution Radiometer on NOAA spacecrafts; and the Cartesian components of the 10m height wind vector computed by the European Center for Medium Range Weather Forecasting. Charts of monthly mean value, sampling distribution, and standard deviation value are displayed. Annual mean distributions are displayed.

  9. Effects of airway surface liquid height on the kinetics of extracellular nucleotides in airway epithelia.

    Science.gov (United States)

    Amarante, Tauanne D; da Silva, Jafferson K L; Garcia, Guilherme J M

    2014-12-21

    Experimental techniques aimed at measuring the concentration of signaling molecules in the airway surface liquid (ASL) often require an unrealistically large ASL volume to facilitate sampling. This experimental limitation, prompted by the difficulty of pipetting liquid from a very shallow layer (~15 μm), leads to dilution and the under-prediction of physiologic concentrations of signaling molecules that are vital to the regulation of mucociliary clearance. Here, we use a computational model to describe the effect of liquid height on the kinetics of extracellular nucleotides in the airway surface liquid coating respiratory epithelia. The model consists of a reaction-diffusion equation with boundary conditions that represent the enzymatic reactions occurring on the epithelial surface. The simulations reproduce successfully the kinetics of extracellular ATP following hypotonic challenge for ASL volumes ranging from 25 μl to 500 μl in a 12-mm diameter cell culture. The model reveals that [ATP] and [ADO] reach 1200 nM and 2200 nM at the epithelial surface, respectively, while their volumetric averages remain less than 200 nM at all times in experiments with a large ASL volume (500 μl). These findings imply that activation of P2Y2 and A2B receptors is robust after hypotonic challenge, in contrast to what could be concluded based on experimental measurements of volumetric concentrations in large ASL volumes. Finally, given the central role that ATP and ADO play in regulating mucociliary clearance, we investigated which enzymes, when inhibited, provide the greatest increase in ATP and ADO concentrations. Our findings suggest that inhibition of NTPDase1/highTNAP would cause the greatest increase in [ATP] after hypotonic challenge, while inhibition of the transporter CNT3 would provide the greatest increase in [ADO]. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Improving the Accuracy of Coastal Sea Surface Heights by Retracking Decontaminated Radar Altimetry Waveforms

    Science.gov (United States)

    Huang, Zhengkai; Wang, Haihong; Luo, Zhicai

    2017-04-01

    Due to the complex coastal topography and energetic ocean dynamics effect, the return echoes are contaminated while the satellite footprint approaches or leaves the coastline. Specular peaks are often induced in the trailing edges of contaminated waveforms, thus leading the error in the determination of the leading edge and associated track offset in the waveform retracking process. We propose an improved algorithm base on Tseng's modification method to decontaminated coastal (0-7 km from coastline) waveforms, thus improving both the utilization and precision of coastal sea surface height (SSH). Using the Envisat/Jason-2 SGDR data, the shortcoming of Tseng's method is pointed out and the novel algorithm is proposed by revising the strategy of selecting reference waveform and determining weight for removing outlier. The reference waveform of the decontaminated technology is closer to the real waveform of the offshore area, which avoids the over-modification problem of Tseng method. The sea-level measurements from tide gauge station and geoid height from EGM2008 model were used to validate the retracking strategy. Experimental results show that decontaminated waveform was more suitable than original and Tseng modified waveform and has uniform performance in both compare to the tide gauge and geoid. The retrieved altimetry data in the 0-1km and 1-7km coastal zone indicate that threshold retracker with decontaminated waveform have STD of 73.8cm and 33cm as compared with in situ gauge data,which correspond to 62.1% and 58% in precession compared to the unretracked altimetry measurements. The retracked SSHs are better in two coastal (0-1 km and 1-7km) zones, which have STD of 11.9cm and 22.7cm as compared with geoid height. Furthermore, the comparisons shows that the precision of decontaminated technology improve 0.3cm and 3.3cm than the best result of PISTACH product in coastal sea. This work is supported by the National Natural Science Foundation of China (Grant Nos

  11. Assessment of the quality of HY-2A satellite sea surface height data

    Science.gov (United States)

    Song, Qingtao; Gao, Xuemin; Wang, Zhaohui; Liu, Yuxin

    2017-10-01

    In August 2011, China successfully launched the Ocean II (HY-2A) satellite. HY-2A carries a dual-band radar altimeter with a calibrated microwave radiometer on the orbit. The main objective of HY-2A is to observe the elements of marine dynamic environment, including sea surface height. The evaluation of HY-2A satellite sea surface data quality is a necessary part of HY-2A satellite sea surface data application. We Used the HY-2A satellite 18th to 23th cycle data and the simultaneous Jason-2 data in orbit to analyze the deviation and evaluate of HY-2A satellite radar height data quality. The results show that the number of abnormal points in HY-2A satellite 18 to 23 cycles accounted for 12% of the total. HY-2A and Jason-2 sea level anomaly standard deviation of 7.0 cm that the accuracy of HY-2A reached the satisfaction index.

  12. Sea surface height determination in the arctic ocean from Cryosat2 SAR data, the impact of using different empirical retrackers

    DEFF Research Database (Denmark)

    Jain, Maulik; Andersen, Ole Baltazar; Stenseng, Lars

    2012-01-01

    Cryosat2 Level 1B SAR data can be processed using different empirical retrackers to determine the sea surface height and its variations in the Arctic Ocean. Two improved retrackers based on the combination of OCOG (Offset Centre of Gravity), Threshold methods and Leading Edge Retrieval is used...... to estimate the sea surface height in the Arctic Region. This sea surface height determination is to be compared with the Level2 sea surface height components available in the Cryosat2 data. Further a comparison is done with the marine gravity field for retracker performance evaluation....

  13. Primary and Secondary Controls on Measurements of Forest Height Using Large-Footprint Lidar at the Hubbard Brook LTER

    Science.gov (United States)

    Knox, Robert G.; Blair, J. Bryan; Schwarz, Paul A.; Hofton, Michelle A.; Dubayah, Ralph; Smith, David E. (Technical Monitor)

    2000-01-01

    On September 26, 1999, we mapped canopy structure over 90% of the Hubbard Brook Experimental Forest in White Mountain National Forest, New Hampshire, using the Laser Vegetation Imaging Sensor (LVIS). This airborne instrument was configured to emulate data expected from the Vegetation Canopy Lidar (VCL) space mission. We compared above ground heights of the tallest surfaces detected by lidar with average forest canopy heights estimated from tree-based measurements in or near 346 0.05 ha plots (made in autumn of 1997 and 1998). Vegetation heights had by far the predominant influence on lidar top heights, but with this large data set we were able to measure two significant secondary effects: those of steepness or slope of the underlying terrain and of tree crown form. The size of the slope effect was intermediate between that expected from models of homogeneous canopy layers and for solitary tree crowns. The first detected surfaces were also proportionately taller for plots with more basal area in broad leaved northern hardwoods than for mostly coniferous plots. We expected this because of the contrast between the shapes of cumulative distributions of surface area for elliptical or hemi-elliptical tree crowns and those for conical crowns. Correcting for these secondary effects, when appropriate data are available for calibration, may improve vegetation structure estimates in regional studies using VCL or similar lidar data sources.

  14. Sea surface height evidence for long-term warming effects of tropical cyclones on the ocean.

    Science.gov (United States)

    Mei, Wei; Primeau, François; McWilliams, James C; Pasquero, Claudia

    2013-09-17

    Tropical cyclones have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this warming effect is still lacking. We quantified cyclone-induced ocean warming by directly monitoring the thermal expansion of water in the wake of cyclones, using satellite-based sea surface height data that provide a unique way of tracking the changes in ocean heat content on seasonal and longer timescales. We find that the long-term effect of cyclones is to warm the ocean at a rate of 0.32 ± 0.15 PW between 1993 and 2009, i.e., ∼23 times more efficiently per unit area than the background equatorial warming, making cyclones potentially important modulators of the climate by affecting heat transport in the ocean-atmosphere system. Furthermore, our analysis reveals that the rate of warming increases with cyclone intensity. This, together with a predicted shift in the distribution of cyclones toward higher intensities as climate warms, suggests the ocean will get even warmer, possibly leading to a positive feedback.

  15. Signal Processing for Determining Water Height in Steam Pipes with Dynamic Surface Conditions

    Science.gov (United States)

    Lih, Shyh-Shiuh; Lee, Hyeong Jae; Bar-Cohen, Yoseph

    2015-01-01

    An enhanced signal processing method based on the filtered Hilbert envelope of the auto-correlation function of the wave signal has been developed to monitor the height of condensed water through the steel wall of steam pipes with dynamic surface conditions. The developed signal processing algorithm can also be used to estimate the thickness of the pipe to determine the cut-off frequency for the low pass filter frequency of the Hilbert Envelope. Testing and analysis results by using the developed technique for dynamic surface conditions are presented. A multiple array of transducers setup and methodology are proposed for both the pulse-echo and pitch-catch signals to monitor the fluctuation of the water height due to disturbance, water flow, and other anomaly conditions.

  16. Bone height measurements of implant sites: Comparison of panoramic radiography and spiral computed tomography

    International Nuclear Information System (INIS)

    Cho, Bong Hae

    2002-01-01

    To compare the bone height of implant sites measured using panoramic radiography and spiral CT. The available bone height was determined for 263 maxillary and mandibular implant sites in 59 patients. Distortion was calculated using the metal bar for the panoramic radiographs. Significant differences in mean bone height between the two imaging modalities were found in maxillary and mandibular anterior regions (p<0.05). The mean difference in bone height recorded by the two techniques was smallest in the maxillary and mandibular molar areas (0.8 mm), and greatest in the mandibular anterior region (1.3 mm). With the exception of the mandibular anterior region, ninety percent of all the sites showed measurement differences within 2 mm. A safety margin of 2 to 3 mm is called for when utilizing panoramic radiography, otherwise additional imaging modality such as computed tomography is necessary to obtain accurate measurements.

  17. Characterization of model errors in the calculation of tangent heights for atmospheric infrared limb measurements

    Directory of Open Access Journals (Sweden)

    M. Ridolfi

    2014-12-01

    Full Text Available We review the main factors driving the calculation of the tangent height of spaceborne limb measurements: the ray-tracing method, the refractive index model and the assumed atmosphere. We find that commonly used ray tracing and refraction models are very accurate, at least in the mid-infrared. The factor with largest effect in the tangent height calculation is the assumed atmosphere. Using a climatological model in place of the real atmosphere may cause tangent height errors up to ± 200 m. Depending on the adopted retrieval scheme, these errors may have a significant impact on the derived profiles.

  18. Quantitative evaluation of die casting surface defect severity by analyzing surface height

    Directory of Open Access Journals (Sweden)

    Yan Xu

    2017-11-01

    Full Text Available It is necessary in factories to assess the severity of the surface defects of castings, as a slight surface defect will be taken as qualified when it brings no bad effect or it can be removed by the subsequent processing. In practical production, professional technicians visually inspect the surface defect severity according to their individual experience. Therefore, it is difficult for them to maintain the same standard and accuracy in the subjective, tedious and labor-intensive work. Recently, image processing techniques based on optical images have been applied to achieve better accuracy and high efficiency. Unfortunately, optical images cannot directly quantify surface depth, which works as a crucial factor in the practical assessment of surface defect severity. The surface roughness evaluation algorithm, which takes into account of both area and depth information of the assessed surface, was applied to directly characterize surface defect severity based on surface asperity rather than optical image. The results using standard casting pieces show that surface defect severity has no apparent dependence on surface roughness. However, the subsequent results show that the root-mean-squared-deviation (RMSD of surface gradient of flow line defects positively correlates with the increase of defect severity. The other types of defect do not present such tendency. Thus, practical workpieces with flow line defects on the surface were used to verify the universality of this tendency. The results show that surface roughness of an unqualified workpiece is larger than that of a qualified workpiece after surface slope adjustment, but presents no obvious coincidence before the adjustment. In contrast, the RMSD of an unqualified workpiece, no matter before or after the adjustment, is larger than that of a qualified one.

  19. Measured parental height in Turner syndrome-a valuable but underused diagnostic tool.

    Science.gov (United States)

    Ouarezki, Yasmine; Cizmecioglu, Filiz Mine; Mansour, Chourouk; Jones, Jeremy Huw; Gault, Emma Jane; Mason, Avril; Donaldson, Malcolm D C

    2018-02-01

    Early diagnosis of Turner syndrome (TS) is necessary to facilitate appropriate management, including growth promotion. Not all girls with TS have overt short stature, and comparison with parental height (Ht) is needed for appropriate evaluation. We examined both the prevalence and diagnostic sensitivity of measured parental Ht in a dedicated TS clinic between 1989 and 2013. Lower end of parental target range (LTR) was calculated as mid-parental Ht (correction factor 12.5 cm minus 8.5 cm) and converted to standard deviation scores (SDS) using UK 1990 data, then compared with patient Ht SDS at first accurate measurement aged > 1 year. Information was available in 172 girls of whom 142 (82.6%) were short at first measurement. However, both parents had been measured in only 94 girls (54.6%). In 92 of these girls age at measurement was 6.93 ± 3.9 years, Ht SDS vs LTR SDS - 2.63 ± 0.94 vs - 1.77 ± 0.81 (p Turner syndrome are short in relation to parental heights, with untreated final height approximately 20 cm below female population mean. • Measured parental height is more accurate than reported height. What is New: • In a dedicated Turner clinic, there was 85% sensitivity when comparing patient height standard deviation score at first accurate measurement beyond 1 year of age with the lower end of the parental target range standard deviation. • However, measured height in both parents had been recorded in only 54.6% of the Turner girls attending the clinic. This indicates the need to improve the quality of growth assessment in tertiary care.

  20. Spectral decomposition of internal gravity wave sea surface height in global models

    Science.gov (United States)

    Savage, Anna C.; Arbic, Brian K.; Alford, Matthew H.; Ansong, Joseph K.; Farrar, J. Thomas; Menemenlis, Dimitris; O'Rourke, Amanda K.; Richman, James G.; Shriver, Jay F.; Voet, Gunnar; Wallcraft, Alan J.; Zamudio, Luis

    2017-10-01

    Two global ocean models ranging in horizontal resolution from 1/12° to 1/48° are used to study the space and time scales of sea surface height (SSH) signals associated with internal gravity waves (IGWs). Frequency-horizontal wavenumber SSH spectral densities are computed over seven regions of the world ocean from two simulations of the HYbrid Coordinate Ocean Model (HYCOM) and three simulations of the Massachusetts Institute of Technology general circulation model (MITgcm). High wavenumber, high-frequency SSH variance follows the predicted IGW linear dispersion curves. The realism of high-frequency motions (>0.87 cpd) in the models is tested through comparison of the frequency spectral density of dynamic height variance computed from the highest-resolution runs of each model (1/25° HYCOM and 1/48° MITgcm) with dynamic height variance frequency spectral density computed from nine in situ profiling instruments. These high-frequency motions are of particular interest because of their contributions to the small-scale SSH variability that will be observed on a global scale in the upcoming Surface Water and Ocean Topography (SWOT) satellite altimetry mission. The variance at supertidal frequencies can be comparable to the tidal and low-frequency variance for high wavenumbers (length scales smaller than ˜50 km), especially in the higher-resolution simulations. In the highest-resolution simulations, the high-frequency variance can be greater than the low-frequency variance at these scales.

  1. Validation of the Aura Microwave Limb Sounder Temperature and Geopotential Height Measurements

    Science.gov (United States)

    Schwartz, M. J.; Lambert, A.; Manney, G. L.; Read, W. G.; Livesey, N. J.; Froidevaux, L.; Ao, C. O.; Bernath, P. F.; Boone, C. D.; Cofield, R. E.; hide

    2007-01-01

    This paper describes the retrievals algorithm used to determine temperature and height from radiance measurements by the Microwave Limb Sounder on EOS Aura. MLS is a "limbscanning" instrument, meaning that it views the atmosphere along paths that do not intersect the surface - it actually looks forwards from the Aura satellite. This means that the temperature retrievals are for a "profile" of the atmosphere somewhat ahead of the satellite. Because of the need to view a finite sample of the atmosphere, the sample spans a box about 1.5km deep and several tens of kilometers in width; the optical characteristics of the atmosphere mean that the sample is representative of a tube about 200-300km long in the direction of view. The retrievals use temperature analyses from NASA's Goddard Earth Observing System, Version 5 (GEOS-5) data assimilation system as a priori states. The temperature retrievals are somewhat deperrdezt on these a priori states, especially in the lower stratosphere. An important part of the validation of any new dataset involves comparison with other, independent datasets. A large part of this study is concerned with such comparisons, using a number of independent space-based measurements obtained using different techniques, and with meteorological analyses. The MLS temperature data are shown to have biases that vary with height, but also depend on the validation dataset. MLS data are apparently biased slightly cold relative to correlative data in the upper troposphere and slightly warm in the middle stratosphere. A warm MLS bias in the upper stratosphere may be due to a cold bias in GEOS-5 temperatures.

  2. Analysis of a new phase and height algorithm in phase measurement profilometry

    Science.gov (United States)

    Bian, Xintian; Zuo, Fen; Cheng, Ju

    2018-01-01

    Traditional phase measurement profilometry adopts divergent illumination to obtain the height distribution of a measured object accurately. However, the mapping relation between reference plane coordinates and phase distribution must be calculated before measurement. Data are then stored in a computer in the form of a data sheet for standby applications. This study improved the distribution of projected fringes and deducted the phase-height mapping algorithm when the two pupils of the projection and imaging systems are of unequal heights and when the projection and imaging axes are on different planes. With the algorithm, calculating the mapping relation between reference plane coordinates and phase distribution prior to measurement is unnecessary. Thus, the measurement process is simplified, and the construction of an experimental system is made easy. Computer simulation and experimental results confirm the effectiveness of the method.

  3. Relationship between Arm Span Measurements and Body Height in Dinaric Alpes Population: a Systematic Review

    Directory of Open Access Journals (Sweden)

    Bojan Masanovic

    2017-08-01

    Full Text Available Several researches have reported the benefit of using various body parameters in predicting standing height, and arm span happened to be one of the most reliable ones in adults. On the other hand, it is well-known the tallness and body proportions are specific in the area that are covered by Dinaric Alpes. Therefore, the purpose of this study was to investigate the potential relationship between arm span measurements and body height in Dinaric Alpes population. The most visible electronic database (Google Scholar was searched for original research articles available until September 2017. Then research findings were summarized and relationship between arm span measurements and body height in Dinaric Alpes population were identified, as well as areas of future research were recommended. The assessment of body height using various anthropometric measures is very typical from the past centuries and it has been attempted to be studied by many researchers. However, it is important to underline that the arm span has been obtained as the most reliable body indicator for predicting the true height of an individual. However, the studies sampled with the populations lived at Dinaric Alpes mountains have specific estimates. Therefore, all above-mentioned have confirmed the necessity for developing separate body height models for each population on account of ethnic as well as regional differences.

  4. Standing Height and its Estimation Utilizing Foot Length Measurements in Adolescents from Western Region in Kosovo

    Directory of Open Access Journals (Sweden)

    Stevo Popović

    2017-10-01

    Full Text Available The purpose of this research is to examine standing height in both Kosovan genders in the Western Region as well as its association with foot length, as an alternative to estimating standing height. A total of 664 individuals (338 male and 326 female participated in this research. The anthropometric measurements were taken according to the protocol of ISAK. The relationships between body height and foot length were determined using simple correlation coefficients at a ninety-five percent confidence interval. A comparison of means of standing height and foot length between genders was performed using a t-test. After that a linear regression analysis were carried out to examine extent to which foot length can reliably predict standing height. Results displayed that Western Kosovan male are 179.71±6.00cm tall and have a foot length of 26.73±1.20cm, while Western Kosovan female are 166.26±5.23cm tall and have a foot length of 23.66±1.06cm. The results have shown that both genders made Western-Kosovans a tall group, a little bit taller that general Kosovan population. Moreover, the foot length reliably predicts standing height in both genders; but, not reliably enough as arm span. This study also confirms the necessity for developing separate height models for each region in Kosovo as the results from Western-Kosovans don’t correspond to the general values.

  5. Measurement of maxillary sinus volume and available alveolar bone height using computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hak; Han, Won Jeong; Choi, Young Hi; Kim, Eun Kyung [Dankook University College of Medicine, Seoul (Korea, Republic of)

    2003-03-15

    To aid in determining the volume of graft bone required before a maxillary sinus lift procedure and compare the alveolar bone height measurements taken by panoramic radiographs to those by CT images. Data obtained by both panoramic radiographs and CT examination of 25 patients were used in this study. Maxillary sinus volumes from the antral floor to heights of 5 mm, 10 mm, 15 mm, and 20 mm , were calculated. Alveolar bone height was measured on the panoramic images at each maxillary tooth site and corrected by magnification rate (PBH). Available bone height (ABH) and full bone height (FBH) was measured on reconstructed CT images. PBH was compared with ABH and FBH at the maxillary incisors, canines, premolars, and molars. Volumes of the inferior portion of the sinuses were 0.55 {+-} 0.41 cm{sup 3} for 5 mm lifts, 2.11 {+-} 0.68 cm{sup 3} for 10 mm, 4.26 {+-} 1.32 cm{sup 3} for 15 mm, 6.95 {+-} 2.01 cm{sup 3} for 20 mm. For the alveolar bone measurement, measurements by panoramic images were longer than available bone heights determined by CT images at the incisor and canine areas, and shorter than full bone heights on CT images at incisor, premolar, and molar areas (p<0.001). In bone grafting of the maxillary sinus floor, 0,96 cm{sup 3} or more is required for a 5 mm - lift, 2.79 cm{sup 3} or more for a 10 mm - lift, 5.58 cm{sup 3} or more for a 15 mm - lift, and 8.96 cm{sup 3} or more for a 20 mm - lift. Maxillary implant length determined using panoramic radiograph alone could result in underestimation or overestimation, according to the site involved.

  6. Pulse-height response of silicon surface-barrier detectors to high-energy heavy ions

    International Nuclear Information System (INIS)

    Smith, G.D.

    1973-01-01

    The pulse-height defect (PHD) of high-energy heavy ions in silicon surface-barrier detectors can be divided into three components: (1) energy loss in the gold-surface layer, (2) a nuclear-stopping defect, and (3) a defect due to recombination of electron-hole pairs in the plasma created by the heavy ion. The plasma recombination portion of the PHD was the subject of this study using the variation of the PHD with (1) the angle of incidence of incoming heavy ions, and (2) changes in the detector bias. The Tandem Van de Graaff accelerator at Argonne National Laboratory was used to produce scattered beam ions ( 32 S, 35 Cl) and heavy target recoils (Ni, Cu, 98 Mo, Ag, Au) at sufficient energies to produce a significant recombination defect. The results confirm the existence of a recombination zone at the front surface of these detectors and the significance of plasma recombination as a portion of the pulse-height defect. (Diss. Abstr. Int., B)

  7. The Effects of Drop Height and Padding Surface on Bruising of Exportable Apple

    Directory of Open Access Journals (Sweden)

    D Ghanbarian

    2015-03-01

    Full Text Available Unfortunately despite the great ranking of Iran for apple production around the world, the export potential is not suitable. It seems that one of the major causes of poor quality for Iranian apple varieties is bruising damage of this product. Therefore, in this study, some factors affecting the apple bruising were addressed. For this purpose, factorial experiment in a completely randomized design with 72 treatments, including variety factor in three levels (Golden Delicious, Red Delicious and Granny Smith, type of padding surface in four levels (Cardboard on plastic, wood, Rubber on steel and apple and the drop height in six levels (5, 15, 25, 35, 45 and 55 cm with four replications were considered. Moreover, the maximum allowable drop heights of apples along with bruising volume estimation models were studied. Analysis of variance (ANOVA showed that bruising area and volume were significantly affected by all experimental parameters at the 1% level. The comparison test revealed that Granny Smith has tougher tissues and is less prone to vulnerability. Based on the results of this study, the maximum allowable drop heights for the Red Delicious, Golden Delicious and Granny Smith varieties were found to be 12, 15 and 20 cm, respectively. In addition, the effect of apple variety on the dependent parameters was significant. Based on the findings of this study, the bruising due to the impact of apple and apple was lower for the moving apples compared with the stationary apples.

  8. Influence of abutment height and surface roughness on in vitro retention of three luting agents.

    Science.gov (United States)

    Cano-Batalla, Jordi; Soliva-Garriga, Joan; Campillo-Funollet, Marc; Munoz-Viveros, Carlos A; Giner-Tarrida, Lluis

    2012-01-01

    This study evaluated the effects of abutment height, airborne-particle abrasion, and type of cement on the tensile resistance to dislodgement of cement-retained implant restorations. Three groups of 12 standardized abutments each were prepared with different heights (4 mm, 5 mm, and 6 mm) using a milling machine. Crowns were cast in cobalt-chrome using the lost-wax technique, airborne particle-abraded using 50-Μm aluminum oxide, and cleaned with acetone. Restorations were cemented using a noneugenol acrylic urethane cement, a resin-modified glass ionomer, or a zinc oxide-noneugenol cement. A 5-kg load was applied for 10 minutes. Samples were kept at 37°C and 100% humidity overnight. A tensile force was applied to the crown using a testing machine at a crosshead speed of 5 mm/minute until failure occurred. Next, the abutments were airborne particle-abraded with 50-Μm aluminum oxide, and the cementation and testing procedures were repeated. The effects of cement, abutment height, and surface treatment were evaluated statistically. There were significant differences among the cements. The resin-modified glass ionomer provided the greatest retention in all the tested conditions, while the zinc oxide-noneugenol cement produced the lowest retention values. Significant differences were also detected between 4-mm and 6-mm abutments, with the 6-mm abutments being more retentive. No differences were found between 4-mm and 5-mm abutments or between 5-mm and 6-mm abutments. The effect of airborne-particle abrasion was also found to be significant. A maximum increase of 90 N in retention force was observed after airborne-particle abrasion for the 5-mm abutments cemented with the acrylic urethane cement. Cement, airborne-particle abrasion, and abutment height can significantly influence retention of implant-supported crowns. Different parameters, including those specific to the patient, should be considered in the selection of a luting agent.

  9. NASA's Space Lidar Measurements of Earth and Planetary Surfaces

    Science.gov (United States)

    Abshire, James B.

    2010-01-01

    A lidar instrument on a spacecraft was first used to measure planetary surface height and topography on the Apollo 15 mission to the Moon in 1971, The lidar was based around a flashlamp-pumped ruby laser, and the Apollo 15-17 missions used them to make a few thousand measurements of lunar surface height from orbit. With the advent of diode pumped lasers in the late 1980s, the lifetime, efficiency, resolution and mass of lasers and space lidar all improved dramatically. These advances were utilized in NASA space missions to map the shape and surface topography of Mars with > 600 million measurements, demonstrate initial space measurements of the Earth's topography, and measured the detailed shape of asteroid. NASA's ICESat mission in Earth orbit just completed its polar ice measurement mission with almost 2 billion measurements of the Earth's surface and atmosphere, and demonstrated measurements to Antarctica and Greenland with a height resolution of a few em. Space missions presently in cruise phase and in operation include those to Mercury and a topographic mapping mission of the Moon. Orbital lidar also have been used in experiments to demonstrate laser ranging over planetary distances, including laser pulse transmission from Earth to Mars orbit. Based on the demonstrated value of the measurements, lidar is now the preferred measurement approach for many new scientific space missions. Some missions planned by NASA include a planetary mission to measure the shape and dynamics of Europa, and several Earth orbiting missions to continue monitoring ice sheet heights, measure vegetation heights, assess atmospheric CO2 concentrations, and to map the Earth surface topographic heights with 5 m spatial resolution. This presentation will give an overview of history, ongoing work, and plans for using space lidar for measurements of the surfaces of the Earth and planets.

  10. Comparison of measured and modelled mixing heights during the Borex`95 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelsen, T.; Astrup, P.; Joergensen, H.E.; Ott, S. [Risoe National Lab., Roskilde (Denmark); Soerensen, J.H. [Danish Meteorological Inst., Copenhagen (Denmark); Loefstroem, P. [National Environmental Research Inst., Roskilde (Denmark)

    1997-10-01

    A real-time modelling system designed for `on-the-fly` assessment of atmospheric dispersion during accidental releases is under establishment within the framework of the European Union. It integrates real-time dispersion models for both local scale and long range transport with wind, turbulence and deposition models. As meteorological input, the system uses both on-situ measured and on-line available meteorology. The resulting real-time dispersion system is called MET-RODOS. This paper focuses on evaluation of the MET-RODOS systems build-in local scale pre-processing software for real-time determination of mixing height, - an important parameter for the local scale dispersion assessments. The paper discusses the systems local scale mixing height algorithms as well as its in-line mixing height acquisition from the DMI-HIRLAM model. Comparisons of the diurnal mixing height evolution is made with measured mixing heights from in-situ radio-sonde data during the Borex`95 field trials, and recently also with remote sensed (LIDAR) aerosol profiles measured at Risoe. (LN)

  11. Body Height and Its Estimation Utilizing Arm Span Measurements in Bosnian and Herzegovinian Adults

    Directory of Open Access Journals (Sweden)

    Stevo Popovic

    2015-03-01

    Full Text Available Anthropologists recognized the tallness of nations in the Dinaric Alps long time ago. As the modern Bosnian and Herzegovinian fall more into the Dinaric racial classification, the purpose of this study was to examine the body height in Bosnian and Herzegovinian adults as well as the relationship between arm span as an alternative to estimating the body height and body height, which vary in different ethnic and racial groups. The nature and scope of this study analyzes 212 students (178 men, aged 22.42±2.79 and 34 women, aged 21.56±2.06 from the University of Banjaluka to be subjects. The anthropometric measurements were taken according to the protocol of the ISAK. Means and standard deviations were obtained. A comparison of means of body heights and arm spans within each gender group and between genders were carried out using a t-test. The relationships between body height and arm span were determined using simple correlation coefficients and their 95% confidence interval. Then a linear regression analysis was performed to examine the extent to which the arm span can reliably predict body height. The results have shown that male Bosnian and Herzegovinians are 183.87±7.11 cm tall and have an arm span of 184.50±8.28 cm, while female Bosnian and Herzegovinians are 171.82±6.56 cm tall and have an arm span of 169.85±8.01 cm. Compared to other studies, the results of this one have shown that both genders make Bosnian and Herzegovinian population one of the tallest nations on the earth, maybe the tallest one. Moreover, the arm span reliably predicts body height in both genders. However, the estimation equations, which were obtained in Bosnian and Herzegovinians, are substantially different alike in other populations, since arm span was close to body heights: in men 0.73±1.17 cm more than the body height and in women 1.97±1.45 centimeters less than the body height. This confirms the necessity for developing separate height models for each

  12. Estimating Tree Height and Diameter at Breast Height (DBH from Digital Surface Models and Orthophotos Obtained with an Unmanned Aerial System for a Japanese Cypress (Chamaecyparis obtusa Forest

    Directory of Open Access Journals (Sweden)

    Kotaro Iizuka

    2017-12-01

    Full Text Available Methods for accurately measuring biophysical parameters are a key component for quantitative evaluation regarding to various forest applications. Conventional in situ measurements of these parameters take time and expense, encountering difficultness at locations with heterogeneous microtopography. To obtain precise biophysical data in such situations, we deployed an unmanned aerial system (UAS multirotor drone in a cypress forest in a mountainous area of Japan. The structure from motion (SfM method was used to construct a three-dimensional (3D model of the forest (tree structures from aerial photos. Tree height was estimated from the 3D model and compared to in situ ground data. We also analyzed the relationships between a biophysical parameter, diameter at breast height (DBH, of individual trees with canopy width and area measured from orthorectified images. Despite the constraints of ground exposure in a highly dense forest area, tree height was estimated at an accuracy of root mean square error = 1.712 m for observed tree heights ranging from 16 to 24 m. DBH was highly correlated with canopy width (R2 = 0.7786 and canopy area (R2 = 0.7923, where DBH ranged from 11 to 58 cm. The results of estimating forest parameters indicate that drone-based remote-sensing methods can be utilized to accurately analyze the spatial extent of forest structures.

  13. 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.

  14. Direct Measurement of Tree Height Provides Different Results on the Assessment of LiDAR Accuracy

    Directory of Open Access Journals (Sweden)

    Emanuele Sibona

    2016-12-01

    Full Text Available In this study, airborne laser scanning-based and traditional field-based survey methods for tree heights estimation are assessed by using one hundred felled trees as a reference dataset. Comparisons between remote sensing and field-based methods were applied to four circular permanent plots located in the western Italian Alps and established within the Alpine Space project NewFor. Remote sensing (Airborne Laser Scanning, ALS, traditional field-based (indirect measurement, IND, and direct measurement of felled trees (DIR methods were compared by using summary statistics, linear regression models, and variation partitioning. Our results show that tree height estimates by Airborne Laser Scanning (ALS approximated to real heights (DIR of felled trees. Considering the species separately, Larix decidua was the species that showed the smaller mean absolute difference (0.95 m between remote sensing (ALS and direct field (DIR data, followed by Picea abies and Pinus sylvestris (1.13 m and 1.04 m, respectively. Our results cannot be generalized to ALS surveys with low pulses density (<5/m2 and with view angles far from zero (nadir. We observed that the tree heights estimation by laser scanner is closer to actual tree heights (DIR than traditional field-based survey, and this was particularly valid for tall trees with conical shape crowns.

  15. Traceability of Height Measurements on Green Sand Molds using Optical 3D Scanning

    DEFF Research Database (Denmark)

    Mohaghegh, Kamran; Yazdanbakhsh, S.A.; Tiedje, N. S.

    2016-01-01

    . This paper presents a metrological approach for height measurement on green sand molds using an optical 3D scanner with fringe projection. A new sand sample was developed with a hard binder to withstand the contact force of a touch probe, while keeping optical cooperativeness similar to green sand...

  16. Physical Retracking of Cryosat-2 Low Resolution Mode data for ocean surface height and gravity field estimation in open ocean

    Science.gov (United States)

    Jain, Maulik; Baltazar Andersen, Ole; Dall, Jorgen; Stenseng, Lars

    2014-05-01

    Cryosat-2 Low Resolution Mode (LRM) altimetric data is processed to determine precise ocean surface heights and gravity fields in open ocean. These ocean surface heights are corrected using various geophysical corrections available. The along track variation of the ocean surface height anomaly is used to determine the gravity field. The quality of this gravity field estimation is dependent on the precision in the ocean surface height anomaly. Thus a three/two parameter based physical model based on an error function is used, and the Cryosat-2 LRM waveforms are fit to this model. The fitting routines which employ the Levenberg Marquadt technique generate estimated values of retracked epochs which are used to compute the ocean surface heights. A two step processing system made up of sequential 3 parameter (amplitude, rise time, retracked epoch) and 2 parameter (amplitude, retracked epoch) fitting models are used to determine precise ocean surface heights. The quality of the processing system is judged by evaluating the standard deviation of the ocean surface height anomaly obtained after all corrections and the mean sea surface/geoid are removed. The lower the value of the standard deviation of the ocean surface height anomaly, the better the quality of processing is. Hence, different processing schemes are considered and evaluated in order to conclude towards the best retracking procedure which would eventually result in high accuracy gravity field estimations. Also, the quality on the precision is judged by analyzing the standard deviation in the gravity field anomaly. The gravity field anomaly is obtained by subtracting the retracked gravity field with the marine gravity field available. A lower value of the standard deviation in the gravity field anomaly indicates a more precise retracking algorithm. Using the two retracker performance evaluation strategies, namely the ocean surface height anomaly and the gravity field anomaly, it was concluded that the three

  17. Concordance of self-report and measured height and weight of college students.

    Science.gov (United States)

    Quick, Virginia; Byrd-Bredbenner, Carol; Shoff, Suzanne; White, Adrienne A; Lohse, Barbara; Horacek, Tanya; Kattelmann, Kendra; Phillips, Beatrice; Hoerr, Sharon L; Greene, Geoffrey

    2015-01-01

    This study examined associations between college students' self-report and measured height and weight. Participants (N = 1,686) were 77% white, 62% female, aged 18-24 years (mean ± SD, 19.1 ± 1.1 years), and enrolled at 8 US universities. Body mass index (BMI) was calculated for self-report (via online survey); trained researchers measured height and weight and categorized them as normal (18.5 to obese (30 to obese (≥ 35). Concordance of self-report vs objectively measured BMI groups using chi-square revealed that 93% were accurate, 4% were underestimated, and 2.7% were overestimated. Pearson correlations and adjusted linear regression revealed significant associations between self-report and measured BMI (r = .97; P college students. Copyright © 2015 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  18. Adjusting adiposity and body weight measurements for height alters the relationship with blood pressure in children

    Science.gov (United States)

    Willig, Amanda L.; Casazza, Krista; Dulin-Keita, Akilah; Franklin, Frank A.; Amaya, Michelle; Fernandez, Jose R.

    2010-01-01

    BACKGROUND Adiposity measures are associated with increased pediatric blood pressure. However, this correlation can be confounded by the relationship of both variables to height. We evaluated whether adiposity and anthropometric measures were associated with pediatric blood pressure before and after adjusting each value for height. METHODS Participants included 281 African-American, European-American, and Hispanic-American children aged 7–12 years. Blood pressure percentiles were calculated according to pediatric guidelines using the average of four measurements. Total fat mass was determined using dual-energy x-ray absorptiometry. Socioeconomic status was calculated with the Hollingshead index. Adiposity measures were indexed for height using log-log regression analysis. Partial correlations identified measures associated with blood pressure. Linear regression was used to test the association of those measures with absolute blood pressure, while logistic regression was used to evaluate the odds for hypertension. RESULTS More African-Americans (16.3%) presented with potential hypertension than European-American (5.1%) or Hispanic-American (2.7%) children. After adjusting for covariates, fat mass, body mass index, and waist circumference were positively significantly associated with absolute blood pressure and hypertension in African-American and European-American children (P < 0.05). When these measures were height-indexed, only waist remained significantly positively associated with hypertension risk in these two groups. No measures were significantly associated with blood pressure among Hispanic-American children. CONCLUSIONS In this multiethnic pediatric population, waist circumference was the strongest significant adiposity predictor of hypertension risk among African-American and European-American children. Additional research is needed to determine which environmental and genetic factors contribute to pediatric hypertension, particularly among Hispanic

  19. Assimilation of ocean sea-surface height observations of mesoscale eddies

    Science.gov (United States)

    Weiss, Jeffrey B.; Grooms, Ian

    2017-12-01

    Mesoscale eddies are one of the dominant sources of variability in the world's oceans. With eddy-resolving global ocean models, it becomes important to assimilate observations of mesoscale eddies to correctly represent the state of the mesoscale. Here, we investigate strategies for assimilating a reduced number of sea-surface height observations by focusing on the coherent mesoscale eddies. The study is carried out in an idealized perfect-model framework using two-layer forced quasigeostrophic dynamics, which captures the dominant dynamics of ocean mesoscale eddies. We study errors in state-estimation as well as error growth in forecasts and find that as fewer observations are assimilated, assimilating at vortex locations results in reduced state estimation and forecast errors.

  20. A Comparison of Mangrove Canopy Height Using Multiple Independent Measurements from Land, Air, and Space

    Science.gov (United States)

    Lagomasino, David; Fatoyinbo, Temilola; Lee, SeungKuk; Feliciano, Emanuelle; Trettin, Carl; Simard, Marc

    2016-01-01

    Canopy height is one of the strongest predictors of biomass and carbon in forested ecosystems. Additionally, mangrove ecosystems represent one of the most concentrated carbon reservoirs that are rapidly degrading as a result of deforestation, development, and hydrologic manipulation. Therefore, the accuracy of Canopy Height Models (CHM) over mangrove forest can provide crucial information for monitoring and verification protocols. We compared four CHMs derived from independent remotely sensed imagery and identified potential errors and bias between measurement types. CHMs were derived from three spaceborne datasets; Very-High Resolution (VHR) stereophotogrammetry, TerraSAR-X add-on for Digital Elevation Measurement (DEM), and Shuttle Radar Topography Mission (TanDEM-X), and lidar data which was acquired from an airborne platform. Each dataset exhibited different error characteristics that were related to spatial resolution, sensitivities of the sensors, and reference frames. Canopies over 10 meters were accurately predicted by all CHMs while the distributions of canopy height were best predicted by the VHR CHM. Depending on the guidelines and strategies needed for monitoring and verification activities, coarse resolution CHMs could be used to track canopy height at regional and global scales with finer resolution imagery used to validate and monitor critical areas undergoing rapid changes.

  1. A Comparison of Mangrove Canopy Height Using Multiple Independent Measurements from Land, Air, and Space

    Directory of Open Access Journals (Sweden)

    David Lagomasino

    2016-04-01

    Full Text Available Canopy height is one of the strongest predictors of biomass and carbon in forested ecosystems. Additionally, mangrove ecosystems represent one of the most concentrated carbon reservoirs that are rapidly degrading as a result of deforestation, development, and hydrologic manipulation. Therefore, the accuracy of Canopy Height Models (CHM over mangrove forest can provide crucial information for monitoring and verification protocols. We compared four CHMs derived from independent remotely sensed imagery and identified potential errors and bias between measurement types. CHMs were derived from three spaceborne datasets; Very-High Resolution (VHR stereophotogrammetry, TerraSAR-X add-on for Digital Elevation Measurement, and Shuttle Radar Topography Mission (TanDEM-X, and lidar data which was acquired from an airborne platform. Each dataset exhibited different error characteristics that were related to spatial resolution, sensitivities of the sensors, and reference frames. Canopies over 10 m were accurately predicted by all CHMs while the distributions of canopy height were best predicted by the VHR CHM. Depending on the guidelines and strategies needed for monitoring and verification activities, coarse resolution CHMs could be used to track canopy height at regional and global scales with finer resolution imagery used to validate and monitor critical areas undergoing rapid changes.

  2. Adjusting altimetric sea surface height observations in coastal regions. Case study in the Greek Seas

    Directory of Open Access Journals (Sweden)

    Mintourakis Ioannis

    2014-09-01

    Full Text Available When processing satellite altimetry data for Mean Sea Surface (MSS modelling in coastal environments many problems arise. The degradation of the accuracy of the Sea Surface Height (SSH observations close to the coastline and the usually irregular pattern and variability of the sea surface topography are the two dominant factors which have to be addressed. In the present paper, we study the statistical behavior of the SSH observations in relation to the range from the coastline for many satellite altimetry missions and we make an effort to minimize the effects of the ocean variability. Based on the above concepts we present a process strategy for the homogenization of multi satellite altimetry data that takes advantage ofweighted SSH observations and applies high degree polynomials for the adjustment and their uniffcation at a common epoch. At each step we present the contribution of each concept to MSS modelling and then we develop a MSS, a marine geoid model and a grid of gravity Free Air Anomalies (FAA for the area under study. Finally, we evaluate the accuracy of the resulting models by comparisons to state of the art global models and other available data such as GPS/leveling points, marine GPS SSH’s and marine gravity FAA’s, in order to investigate any progress achieved by the presented strategy

  3. Sensitivity Analysis of Dune Height Measurements Along Cross-shore Profiles Using a Novel Method for Dune Ridge Extraction

    Science.gov (United States)

    Hardin, E.; Mitasova, H.; Overton, M.

    2010-12-01

    meets landward-facing slope. In this study, a novel approach for dune ridge extraction is proposed. First, two alongshore end-points of the studied dune ridge are identified using a standard, profile-based method. Then, the dune ridge is traced as the least cost path connecting the two end-points on a cost surface that represents the cumulative penalty for tracing a low elevation path. The cost surface is derived from elevation (i.e., elevation is equal to the cologarithm of the cost). The extracted dune ridge is then sampled at the DEM resolution of 0.5m and analysis of dune ridge height is performed. Statistics on variation in dune height are computed to help understand the sensitivity of dune height measurements to profile spacing and placement. Preliminary results suggest that dune height becomes nearly uncorrelated within 50m and ranges on average nearly a half meter within a five meter window suggesting that dune height measurements are sensitive to profile placement.

  4. Surface height adjustments in pyroclastic-flow deposits observed at Unzen volcano by JERS-1 SAR interferometry

    Science.gov (United States)

    Matthews, J. P.; Kamata, H.; Okuyama, S.; Yusa, Y.; Shimizu, H.

    2003-07-01

    number of possible causative mechanisms including hydroconsolidation initiated by the seepage of rainwater into a newly deposited ash sheet, deflation on gas release, basal erosion, settlement and substrate relaxation are discussed here. Given the relatively low emplacement temperatures of the Unzen ash (300-500°C), it is unlikely that viscous deformation within the body of the fresh ash deposits is responsible for the subsidence. Comparison of the 22 July 1993-1 December 1993 interferogram with a LANDSAT 4 Thematic Mapper image of Unzen, acquired on 10 January 1994, highlights a ribbon-like zone of radar decorrelation running along the course of the Mizunashi valley which marks the path of debris flows that occurred within the time interval between the two SAR images used in the construction of the interferogram. Overall, these results demonstrate the utility of interferometric SAR-derived surface height and coherence measurements for monitoring the pyroclastic- and debris-flow regimes of active volcanoes.

  5. DMSA scan nomograms for renal length and area: Related to patient age and to body weight, height or surface area

    International Nuclear Information System (INIS)

    Hassan, I.M.; Que, L.; Rutland, M.D.

    2002-01-01

    Aim: To create nomograms for renal size as measured from DMSA renal studies, and to test the nomograms for their ability to separate normal from abnormal kidneys. Method: Renal length was measured from posterior oblique views and renal area from posterior views. Results from 253 patients with bilateral normal kidneys were used to create nomograms for renal size relative to patient age, body height, weight or body surface area (BSA). The nomograms enclosed 95% of the normal kidneys, thus indicating the range for 95% confidence limits, and hence the specificity. Each nomogram was then tested against 46 hypertrophied kidneys and 46 damaged kidneys. Results: The results from nomograms of renal length and renal area, compared to age, body height, body weight and BSA are presented. For each nomogram, the range is presented as a fraction of the mean value, and the number of abnormal kidneys (hypertrophied or damaged) outside the normal range is presented as a percentage (indicating the sensitivity). Conclusion: Renal Area was no better than renal length for detecting abnormal kidneys. Patient age was the least useful method of normalisation. BSA normalisation produced the best results most frequently (narrower ranges and highest detection of abnormal kidneys)

  6. Remote sensing of multiple cloud layer heights using multi-angular measurements

    Science.gov (United States)

    Sinclair, Kenneth; van Diedenhoven, Bastiaan; Cairns, Brian; Yorks, John; Wasilewski, Andrzej; McGill, Matthew

    2017-06-01

    Cloud top height (CTH) affects the radiative properties of clouds. Improved CTH observations will allow for improved parameterizations in large-scale models and accurate information on CTH is also important when studying variations in freezing point and cloud microphysics. NASA's airborne Research Scanning Polarimeter (RSP) is able to measure cloud top height using a novel multi-angular contrast approach. For the determination of CTH, a set of consecutive nadir reflectances is selected and the cross correlations between this set and collocated sets at other viewing angles are calculated for a range of assumed cloud top heights, yielding a correlation profile. Under the assumption that cloud reflectances are isotropic, local peaks in the correlation profile indicate cloud layers. This technique can be applied to every RSP footprint and we demonstrate that detection of multiple peaks in the correlation profile allows retrieval of heights of multiple cloud layers within single RSP footprints. This paper provides an in-depth description of the architecture and performance of the RSP's CTH retrieval technique using data obtained during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. RSP-retrieved cloud heights are evaluated using collocated data from the Cloud Physics Lidar (CPL). The method's accuracy associated with the magnitude of correlation, optical thickness, cloud thickness and cloud height are explored. The technique is applied to measurements at a wavelength of 670 and 1880 nm and their combination. The 1880 nm band is virtually insensitive to the lower troposphere due to strong water vapor absorption. It is found that each band is well suitable for retrieving heights of cloud layers with optical thicknesses above about 0.1 and that RSP cloud layer height retrievals more accurately correspond to CPL cloud middle than cloud top. It is also found that the 1880 nm band yields the most

  7. Height and Weight Estimation From Anthropometric Measurements Using Machine Learning Regressions.

    Science.gov (United States)

    Rativa, Diego; Fernandes, Bruno J T; Roque, Alexandre

    2018-01-01

    Height and weight are measurements explored to tracking nutritional diseases, energy expenditure, clinical conditions, drug dosages, and infusion rates. Many patients are not ambulant or may be unable to communicate, and a sequence of these factors may not allow accurate estimation or measurements; in those cases, it can be estimated approximately by anthropometric means. Different groups have proposed different linear or non-linear equations which coefficients are obtained by using single or multiple linear regressions. In this paper, we present a complete study of the application of different learning models to estimate height and weight from anthropometric measurements: support vector regression, Gaussian process, and artificial neural networks. The predicted values are significantly more accurate than that obtained with conventional linear regressions. In all the cases, the predictions are non-sensitive to ethnicity, and to gender, if more than two anthropometric parameters are analyzed. The learning model analysis creates new opportunities for anthropometric applications in industry, textile technology, security, and health care.

  8. Optimal Linear Filters for Pulse Height Measurements in the Presence of Noise

    Energy Technology Data Exchange (ETDEWEB)

    Nygaard, K.

    1966-07-15

    For measurements of nuclear pulse height spectra a linear filter is used between the pulse amplifier and the pulse height recorder so as to improve the signal/noise ratio. The problem of finding the optimal filter is investigated with emphasis on technical realizability. The maximum available signal/noise ratio is theoretically calculated on the basis of all the information which can be found in the output of the pulse amplifier, and on an assumed a priori knowledge of the pulse time of arrival. It is then shown that the maximum available signal/noise ratio can be obtained with practical measurements without any a priori knowledge of pulse time of arrival, and a general description of the optimal linear filter is given. The solution is unique, technically realizable, and based solely on data (noise power spectrum and pulse shape) which can be measured at the output terminals of the pulse amplifier used.

  9. Optimal Linear Filters for Pulse Height Measurements in the Presence of Noise

    International Nuclear Information System (INIS)

    Nygaard, K.

    1966-07-01

    For measurements of nuclear pulse height spectra a linear filter is used between the pulse amplifier and the pulse height recorder so as to improve the signal/noise ratio. The problem of finding the optimal filter is investigated with emphasis on technical realizability. The maximum available signal/noise ratio is theoretically calculated on the basis of all the information which can be found in the output of the pulse amplifier, and on an assumed a priori knowledge of the pulse time of arrival. It is then shown that the maximum available signal/noise ratio can be obtained with practical measurements without any a priori knowledge of pulse time of arrival, and a general description of the optimal linear filter is given. The solution is unique, technically realizable, and based solely on data (noise power spectrum and pulse shape) which can be measured at the output terminals of the pulse amplifier used

  10. Tools for measuring surface cleanliness

    Energy Technology Data Exchange (ETDEWEB)

    Schroder, Mark Stewart (Hendersonville, NC); Woodmansee, Donald Ernest (Simpsonville, SC); Beadie, Douglas Frank (Greenville, SC)

    2002-01-01

    A procedure and tools for quantifying surface cleanliness are described. Cleanliness of a target surface is quantified by wiping a prescribed area of the surface with a flexible, bright white cloth swatch, preferably mounted on a special tool. The cloth picks up a substantial amount of any particulate surface contamination. The amount of contamination is determined by measuring the reflectivity loss of the cloth before and after wiping on the contaminated system and comparing that loss to a previous calibration with similar contamination. In the alternative, a visual comparison of the contaminated cloth to a contamination key provides an indication of the surface cleanliness.

  11. The Importance of Tree Height in Estimating Individual Tree Biomass While Considering Errors in Measurements and Allometric Models

    OpenAIRE

    Phalla, Thuch; Ota, Tetsuji; Mizoue, Nobuya; Kajisa, Tsuyoshi; Yoshida, Shigejiro; Vuthy, Ma; Heng, Sokh

    2018-01-01

    This study evaluated the uncertainty of individual tree biomass estimated by allometric models by both including and excluding tree height independently. Using two independent sets of measurements on the same trees, the errors in the measurement of diameter at breast height and tree height were quantified, and the uncertainty of individual tree biomass estimation caused by errors in measurement was calculated. For both allometric models, the uncertainties of the individual tree biomass estima...

  12. A comparison of forest height prediction from FIA field measurement and LiDAR data via spatial models

    Science.gov (United States)

    Yuzhen Li

    2009-01-01

    Previous studies have shown a high correspondence between tree height measurements acquired from airborne LiDAR and that those measured using conventional field techniques. Though these results are very promising, most of the studies were conducted over small experimental areas and tree height was measured carefully or using expensive instruments in the field, which is...

  13. SO2 plume height retrieval from direct fitting of GOME-2 backscattered radiance measurements

    Science.gov (United States)

    van Gent, J.; Spurr, R.; Theys, N.; Lerot, C.; Brenot, H.; Van Roozendael, M.

    2012-04-01

    The use of satellite measurements for SO2 monitoring has become an important aspect in the support of aviation control. Satellite measurements are sometimes the only information available on SO2 concentrations from volcanic eruption events. The detection of SO2 can furthermore serve as a proxy for the presence of volcanic ash that poses a possible hazard to air traffic. In that respect, knowledge of both the total vertical column amount and the effective altitude of the volcanic SO2 plume is valuable information to air traffic control. The Belgian Institute for Space Aeronomy (BIRA-IASB) hosts the ESA-funded Support to Aviation Control Service (SACS). This system provides Volcanic Ash Advisory Centers (VAACs) worldwide with near real-time SO2 and volcanic ash data, derived from measurements from space. We present results from our algorithm for the simultaneous retrieval of total vertical columns of O3 and SO2 and effective SO2 plume height from GOME-2 backscattered radiance measurements. The algorithm is an extension to the GODFIT direct fitting algorithm, initially developed at BIRA-IASB for the derivation of improved total ozone columns from satellite data. The algorithm uses parameterized vertical SO2 profiles which allow for the derivation of the peak height of the SO2 plume, along with the trace gas total column amounts. To illustrate the applicability of the method, we present three case studies on recent volcanic eruptions: Merapi (2010), Grímsvotn (2011), and Nabro (2011). The derived SO2 plume altitude values are validated with the trajectory model FLEXPART and with aerosol altitude estimations from the CALIOP instrument on-board the NASA A-train CALIPSO platform. We find that the effective plume height can be obtained with a precision as fine as 1 km for moderate and strong volcanic events. Since this is valuable information for air traffic, we aim at incorporating the plume height information in the SACS system.

  14. Armor Plate Surface Roughness Measurements

    National Research Council Canada - National Science Library

    Stanton, Brian; Coburn, William; Pizzillo, Thomas J

    2005-01-01

    ...., surface texture and coatings) that could become important at high frequency. We measure waviness and roughness of various plates to know the parameter range for smooth aluminum and rolled homogenous armor (RHA...

  15. A Reliable Method to Measure Lip Height Using Photogrammetry in Unilateral Cleft Lip Patients.

    Science.gov (United States)

    van der Zeeuw, Frederique; Murabit, Amera; Volcano, Johnny; Torensma, Bart; Patel, Brijesh; Hay, Norman; Thorburn, Guy; Morris, Paul; Sommerlad, Brian; Gnarra, Maria; van der Horst, Chantal; Kangesu, Loshan

    2015-09-01

    There is still no reliable tool to determine the outcome of the repaired unilateral cleft lip (UCL). The aim of this study was therefore to develop an accurate, reliable tool to measure vertical lip height from photographs. The authors measured the vertical height of the cutaneous and vermilion parts of the lip in 72 anterior-posterior view photographs of 17 patients with repairs to a UCL. Points on the lip's white roll and vermillion were marked on both the cleft and the noncleft sides on each image. Two new concepts were tested. First, photographs were standardized using the horizontal (medial to lateral) eye fissure width (EFW) for calibration. Second, the authors tested the interpupillary line (IPL) and the alar base line (ABL) for their reliability as horizontal lines of reference. Measurements were taken by 2 independent researchers, at 2 different time points each. Overall 2304 data points were obtained and analyzed. Results showed that the method was very effective in measuring the height of the lip on the cleft side with the noncleft side. When using the IPL, inter- and intra-rater reliability was 0.99 to 1.0, with the ABL it varied from 0.91 to 0.99 with one exception at 0.84. The IPL was easier to define because in some subjects the overhanging nasal tip obscured the alar base and gave more consistent measurements possibly because the reconstructed alar base was sometimes indistinct. However, measurements from the IPL can only give the percentage difference between the left and right sides of the lip, whereas those from the ABL can also give exact measurements. Patient examples were given that show how the measurements correlate with clinical assessment. The authors propose this method of photogrammetry with the innovative use of the IPL as a reliable horizontal plane and use of the EFW for calibration as a useful and reliable tool to assess the outcome of UCL repair.

  16. Tree Height Growth Measurement with Single-Scan Airborne, Static Terrestrial and Mobile Laser Scanning

    Directory of Open Access Journals (Sweden)

    Yi Lin

    2012-09-01

    Full Text Available This study explores the feasibility of applying single-scan airborne, static terrestrial and mobile laser scanning for improving the accuracy of tree height growth measurement. Specifically, compared to the traditional works on forest growth inventory with airborne laser scanning, two issues are regarded: “Can the new technique characterize the height growth for each individual tree?” and “Can this technique refine the minimum growth-discernable temporal interval further?” To solve these two puzzles, the sampling principles of the three laser scanning modes were first examined, and their error sources against the task of tree-top capturing were also analyzed. Next, the three-year growths of 58 Nordic maple trees (Crimson King for test were intermittently surveyed with one type of laser scanning each time and then analyzed by statistics. The evaluations show that the height growth of each individual tree still cannot be reliably characterized even by single-scan terrestrial laser scanning, and statistical analysis is necessary in this scenario. After Gaussian regression, it is found that the minimum temporal interval with distinguishable tree height growths can be refined into one month based on terrestrial laser scanning, far better than the two years deduced in the previous works based on airborne laser scanning. The associated mean growth was detected to be about 0.12 m. Moreover, the parameter of tree height generally under-estimated by airborne and even mobile laser scanning can be relatively revised by means of introducing static terrestrial laser scanning data. Overall, the effectiveness of the proposed technique is primarily validated.

  17. Sea Surface Height Determination In The Arctic Using Cryosat-2 SAR Data From Primary Peak Empirical Retrackers

    DEFF Research Database (Denmark)

    Jain, Maulik; Andersen, Ole Baltazar; Dall, Jørgen

    2015-01-01

    SAR waveforms from Cryosat-2 are processed using primary peak empirical retrackers to determine the sea surface height in the Arctic. The empirical retrackers investigated are based on the combination of the traditional OCOG (Offset Center of Gravity) and threshold methods with primary peak...... are processed using such primary peak retrackers. The sea surface heights determined are compared with the sea surface heights generated by the ESA Retracker as available in the Cryosat-2 Level-2 dataset from 2012. Performance of the primary peak retrackers is also compared with the traditional OCOG, threshold...... extraction. The primary peak retrackers involve the application of retracking algorithms on just the primary peak of the waveform instead of the complete reflected waveform. These primary peak empirical retrackers are developed for Cryosat-2 SAR data. This is the first time SAR data in the Arctic...

  18. Histologically Measured Cardiomyocyte Hypertrophy Correlates with Body Height as Strongly as with Body Mass Index

    Directory of Open Access Journals (Sweden)

    Richard E. Tracy

    2011-01-01

    Full Text Available Cardiac myocytes are presumed to enlarge with left ventricular hypertrophy (LVH. This study correlates histologically measured myocytes with lean and fat body mass. Cases of LVH without coronary heart disease and normal controls came from forensic autopsies. The cross-sectional widths of myocytes in H&E-stained paraffin sections followed log normal distributions almost to perfection in all 104 specimens, with constant coefficient of variation across the full range of ventricular weight, as expected if myocytes of all sizes contribute proportionately to hypertrophy. Myocyte sizes increased with height. By regression analysis, height2.7 as a proxy for lean body mass and body mass index (BMI as a proxy for fat body mass, exerted equal effects in the multiple correlation with myocyte volume, and the equation rejected race and sex. In summary, myocyte sizes, as indexes of LVH, suggest that lean and fat body mass may contribute equally.

  19. New Stereo Vision Digital Camera System for Simultaneous Measurement of Cloud Base Height and Atmospheric Visibility

    Science.gov (United States)

    Janeiro, F. M.; Carretas, F.; Palma, N.; Ramos, P. M.; Wagner, F.

    2013-12-01

    Clouds play an important role in many aspects of everyday life. They affect both the local weather as well as the global climate and are an important parameter on climate change studies. Cloud parameters are also important for weather prediction models which make use of actual measurements. It is thus important to have low-cost instrumentation that can be deployed in the field to measure those parameters. This kind of instruments should also be automated and robust since they may be deployed in remote places and be subject to adverse weather conditions. Although clouds are very important in environmental systems, they are also an essential component of airplane safety when visual flight rules (VFR) are enforced, such as in most small aerodromes where it is not economically viable to install instruments for assisted flying. Under VFR there are strict limits on the height of the cloud base, cloud cover and atmospheric visibility that ensure the safety of the pilots and planes. Although there are instruments, available in the market, to measure those parameters, their relatively high cost makes them unavailable in many local aerodromes. In this work we present a new prototype which has been recently developed and deployed in a local aerodrome as proof of concept. It is composed by two digital cameras that capture photographs of the sky and allow the measurement of the cloud height from the parallax effect. The new developments consist on having a new geometry which allows the simultaneous measurement of cloud base height, wind speed at cloud base height and atmospheric visibility, which was not previously possible with only two cameras. The new orientation of the cameras comes at the cost of a more complex geometry to measure the cloud base height. The atmospheric visibility is calculated from the Lambert-Beer law after the measurement of the contrast between a set of dark objects and the background sky. The prototype includes the latest hardware developments that

  20. An atlas of monthly mean distributions of SSMI surface wind speed, AVHRR/2 sea surface temperature, AMI surface wind velocity, TOPEX/POSEIDON sea surface height, and ECMWF surface wind velocity during 1993

    Science.gov (United States)

    Halpern, D.; Fu, L.; Knauss, W.; Pihos, G.; Brown, O.; Freilich, M.; Wentz, F.

    1995-01-01

    The following monthly mean global distributions for 1993 are presented with a common color scale and geographical map: 10-m height wind speed estimated from the Special Sensor Microwave Imager (SSMI) on a United States (U.S.) Air Force Defense Meteorological Satellite Program (DMSP) spacecraft; sea surface temperature estimated from the Advanced Very High Resolution Radiometer (AVHRR/2) on a U.S. National Oceanic and Atmospheric Administration (NOAA) satellite; 10-m height wind speed and direction estimated from the Active Microwave Instrument (AMI) on the European Space Agency (ESA) European Remote Sensing (ERS-1) satellite; sea surface height estimated from the joint U.S.-France Topography Experiment (TOPEX)/POSEIDON spacecraft; and 10-m height wind speed and direction produced by the European Center for Medium-Range Weather Forecasting (ECMWF). Charts of annual mean, monthly mean, and sampling distributions are displayed.

  1. Intraseasonal Variability of the Equatorial Indian Ocean Observed from Sea Surface Height, Wind, and Temperature Data

    Science.gov (United States)

    Fu, Lee-Lueng

    2007-01-01

    The forcing of the equatorial Indian Ocean by the highly periodic monsoon wind cycle creates many interesting intraseasonal variabilities. The frequency spectrum of the wind stress observations from the European Remote Sensing Satellite scatterometers reveals peaks at the seasonal cycle and its higher harmonics at 180, 120, 90, and 75 days. The observations of sea surface height (SSH) from the Jason and Ocean Topography Experiment (TOPEX)/Poseidon radar altimeters are analyzed to study the ocean's response. The focus of the study is on the intraseasonal periods shorter than the annual period. The semiannual SSH variability is characterized by a basin mode involving Rossby waves and Kelvin waves traveling back and forth in the equatorial Indian Ocean between 10(deg)S and 10(deg)N. However, the interference of these waves with each other masks the appearance of individual Kelvin and Rossby waves, leading to a nodal point (amphidrome) of phase propagation on the equator at the center of the basin. The characteristics of the mode correspond to a resonance of the basin according to theoretical models. The theory also calls for similar modes at 90 and 60 days.

  2. Improving Jason-2 Sea Surface Heights within 10 km Offshore by Retracking Decontaminated Waveforms

    Directory of Open Access Journals (Sweden)

    Zhengkai Huang

    2017-10-01

    Full Text Available It is widely believed that altimetry-derived sea surface heights (SSHs in coastal zones are seriously degraded due to land contamination in altimeter waveforms from non-marine surfaces or due to inhomogeneous sea state conditions. Spurious peaks superimposed in radar waveforms adversely impact waveform retracking and hence require tailored algorithms to mitigate this problem. Here, we present an improved method to decontaminate coastal waveforms based on the waveform modification concept. SSHs within 10 km offshore are calculated from Jason-2 data by a 20% threshold retracker using decontaminated waveforms (DW-TR and compared with those using original waveforms and modified waveforms in four study regions. We then compare our results with retracked SSHs in the sensor geophysical data record (SGDR and with the state-of-the-art PISTACH (Prototype Innovant de Système de Traitement pour les Applications Côtières et l’Hydrologie and ALES (Adaptive Leading Edge Subwaveform products. Our result indicates that the DW-TR is the most robust retracker in the 0–10 km coastal band and provides consistent accuracy up to 1 km away from the coastline. In the four test regions, the DW-TR retracker outperforms other retrackers, with the smallest averaged standard deviations at 15 cm and 20 cm, as compared against the EGM08 (Earth Gravitational Model 2008 geoid model and tide gauge data, respectively. For the SGDR products, only the ICE retracker provides competitive SSHs for coastal applications. Subwaveform retrackers such as ICE3, RED3 and ALES perform well beyond 8 km offshore, but seriously degrade in the 0–8 km strip along the coast.

  3. Real-Time Measurement of Width and Height of Weld Beads in GMAW Processes

    Directory of Open Access Journals (Sweden)

    Jesús Emilio Pinto-Lopera

    2016-09-01

    Full Text Available Associated to the weld quality, the weld bead geometry is one of the most important parameters in welding processes. It is a significant requirement in a welding project, especially in automatic welding systems where a specific width, height, or penetration of weld bead is needed. This paper presents a novel technique for real-time measuring of the width and height of weld beads in gas metal arc welding (GMAW using a single high-speed camera and a long-pass optical filter in a passive vision system. The measuring method is based on digital image processing techniques and the image calibration process is based on projective transformations. The measurement process takes less than 3 milliseconds per image, which allows a transfer rate of more than 300 frames per second. The proposed methodology can be used in any metal transfer mode of a gas metal arc welding process and does not have occlusion problems. The responses of the measurement system, presented here, are in a good agreement with off-line data collected by a common laser-based 3D scanner. Each measurement is compare using a statistical Welch’s t-test of the null hypothesis, which, in any case, does not exceed the threshold of significance level α = 0.01, validating the results and the performance of the proposed vision system.

  4. Estimation of sea surface wave height from Bhaskara II SAMIR data

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, M.V.; Viswambharan, N.K.; Rao, L.V.G.

    significant wave height and brightness temperature at 19 and 22 GHz, and multiple correlation at 19 and 22 GHz are studied. Significant wave height derived from the linear regression at 19 GHz as well as from multiple regression at 19 and 22 GHz, yields better...

  5. Automation of measurement of heights waves around a model ship; Mokeisen mawari no hako keisoku no jidoka

    Energy Technology Data Exchange (ETDEWEB)

    Ikehata, M.; Kato, M.; Yanagida, F. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1997-10-01

    Trial fabrication and tests were performed on an instrument to automate measurement of heights of waves around a model ship. The currently used electric wave height measuring instrument takes long time for measurement, hence poor in efficiency. The method for processing optical images also has a problem in accuracy. Therefore, a computer controlled system was structured by using AC servo motors in driving the X and Y axes of a traverse equipment. Equipment was fabricated to automate the wave height measurement, in which four servo type wave height meters are installed on a moving rack in the lateral (Y-axial) direction so that wave heights to be measured by four meters can be measured automatically all at once. Wave heights can be measured continuously by moving the moving rack at a constant speed, verifying that wave shapes in longitudinal cross sections can be acquired by only one towing. Time required in the measurements using the instrument was 40 hours as a net time for fixed point measurement and 12 hours for continuous measurement, or 52 hours in total. On the other hand, the time may reach 240 hours for fixed point measurement when the conventional all-point manual traverse equipment is used. Enormous effects were obtained from automating the instrument. Collection of wave height data will continue also on tankers and other types of ships. 2 refs., 8 figs., 1 tab.

  6. Navicula height

    DEFF Research Database (Denmark)

    Rathleff, Michael Skovdal; Nielsen, Rasmus Gottschalk N; Olesen, Christian Gammelgaard

    position and relaxed standing posture. Excessive movement of the navicula is considered a predisposing factor in the development of shin splits. No single direct static measurement of navicula height has yet shown to predict a high degree of mid foot movement. The purpose of this study was to investigate......, it was hypothesized that the single leg standing also would be an indicator of navicula drop, and the minimal height of tuberositas navicula during walking. Another test was suggested by Brody, it was named Navicula Drop Test (NDT) and was defined as the difference of navicula height with subtalar joint in neutral...... the relationship between static measurements, using Navicual Drop Test and One Leg Standing (OLS) and the dynamic measurements of minimal navicula height loaded (NHL) and navicula drop (ΔNH)...

  7. Standing Height as a Prevention Measure for Overuse Injuries of the Back in Alpine Ski Racing: A Kinematic and Kinetic Study of Giant Slalom.

    Science.gov (United States)

    Spörri, Jörg; Kröll, Josef; Fasel, Benedikt; Aminian, Kamiar; Müller, Erich

    2018-01-01

    In alpine ski racing, typical loading patterns of the back include a combined occurrence of spinal bending, torsion, and high peak loads. These factors are known to be associated with high spinal disc loading and have been suggested to be attributable to different types of spine deterioration. However, little is known about the effect of standing height (ie, the distance between the bottom of the running surface of the ski and the ski boot sole) on the aforementioned back loading patterns. To investigate the effect of reduced standing height on the skier's overall trunk kinematics and the acting ground-reaction forces in giant slalom (GS) from an overuse injury prevention perspective. Controlled laboratory study. Seven European Cup-level athletes skied a total of 224 GS turns with 2 different pairs of skis varying in standing height. Their overall trunk movement (frontal bending, lateral bending, and torsion angles) was measured based on 2 inertial measurement units located at the sacrum and sternum. Pressure insoles were used to determine the total ground-reaction force. During the turn phase in which the greatest spinal disc loading is expected to occur, significantly lower total ground-reaction forces were observed for skis with a decreased standing height. Simultaneously, the skier's overall trunk movement (ie, frontal bending, lateral bending, and torsion angles) remained unwaveringly high. Standing height is a reasonable measure to reduce the skier's overall back loading in GS. Yet, when compared with the effects achievable by increased gate offsets in slalom, for instance, the preventative benefits of decreased standing height seem to be rather small. To reduce the magnitude of overall back loading in GS and to prevent overuse injuries of the back, decreasing standing height might be an efficient approach. Nevertheless, the clinical relevance of the current findings, as well as the effectiveness of the measure "reduced standing height," must be verified by

  8. Eddy heat flux across the Antarctic Circumpolar Current estimated from sea surface height standard deviation

    Science.gov (United States)

    Foppert, Annie; Donohue, Kathleen A.; Watts, D. Randolph; Tracey, Karen L.

    2017-08-01

    Eddy heat flux (EHF) is a predominant mechanism for heat transport across the zonally unbounded mean flow of the Antarctic Circumpolar Current (ACC). Observations of dynamically relevant, divergent, 4 year mean EHF in Drake Passage from the cDrake project, as well as previous studies of atmospheric and oceanic storm tracks, motivates the use of sea surface height (SSH) standard deviation, H*, as a proxy for depth-integrated, downgradient, time-mean EHF (>[EHF>¯>]) in the ACC. Statistics from the Southern Ocean State Estimate corroborate this choice and validate throughout the ACC the spatial agreement between H* and >[EHF>¯>] seen locally in Drake Passage. Eight regions of elevated >[EHF>¯>] are identified from nearly 23.5 years of satellite altimetry data. Elevated cross-front exchange usually does not span the full latitudinal width of the ACC in each region, implying a hand-off of heat between ACC fronts and frontal zones as they encounter the different >[EHF>¯>] hot spots along their circumpolar path. Integrated along circumpolar streamlines, defined by mean SSH contours, there is a convergence of ∮>[EHF>¯>] in the ACC: 1.06 PW enters from the north and 0.02 PW exits to the south. Temporal trends in low-frequency [EHF] are calculated in a running-mean sense using H* from overlapping 4 year subsets of SSH. Significant increases in downgradient [EHF] magnitude have occurred since 1993 at Kerguelen Plateau, Southeast Indian Ridge, and the Brazil-Malvinas Confluence, whereas the other five >[EHF>¯>] hot spots have insignificant trends of varying sign.

  9. Sea Surface Height Variability and Eddy Statistical Properties in the Red Sea

    KAUST Repository

    Zhan, Peng

    2013-05-01

    Satellite sea surface height (SSH) data over 1992-2012 are analyzed to study the spatial and temporal variability of sea level in the Red Sea. Empirical orthogonal functions (EOF) analysis suggests the remarkable seasonality of SSH in the Red Sea, and a significant correlation is found between SSH variation and seasonal wind cycle. A winding-angle based eddy identification algorithm is employed to derive the mesoscale eddy information from SSH data. Totally more than 5500 eddies are detected, belonging to 2583 eddy tracks. Statistics suggest that eddies generate over the entire Red Sea, with two regions in the central basin of high eddy frequency. 76% of the detected eddies have a radius ranging from 40km to 100km, of which both intensity and absolute vorticity decrease with eddy radius. The average eddy lifespan is about 5 weeks, and eddies with longer lifespan tend to have larger radius but less intensity. Different deformation rate exists between anticyclonic eddies (AEs) and cyclonic eddies (CEs), those eddies with higher intensity appear to be less deformed and more circular. Inspection of the 84 long-lived eddies suggests the AEs tend to move a little more northward than CEs. AE generation during summer is obviously lower than that during other seasons, while CE generation is higher during spring and summer. Other features of AEs and CEs are similar with both vorticity and intensity reaching the summer peaks in August and winter peaks in January. Inter-annual variability reveals that the eddies in the Red Sea are isolated from the global event. The eddy property tendencies are different from the south and north basin, both of which exhibit a two-year cycle. Showing a correlation coefficient of -0.91, Brunt–Väisälä frequency is negatively correlated with eddy kinetic energy (EKE), which results from AE activities in the high eddy frequency region. Climatological vertical velocity shear variation is identical with EKE except in the autumn, suggesting the

  10. Quality control on the mixing layer height retrieved from LIDAR-ceilometer measurements

    Science.gov (United States)

    Laffineur, Quentin; De Backer, Hugo; Delcloo, Andy; Hamdi, Rafiq; Nemeghaire, Jean; Debal, Fabian

    2013-04-01

    LIDAR ceilometers were primarily designed for cloud base height detection (for air traffic safety and weather forecasting). They greatly improved over the last years and now offer the opportunity to monitor the vertical profile of aerosols and the mixing layer height (MLH) on a continuous temporal scale. The knowledge of MLH can improve the forecasting of the dispersion of trace gases and aerosols in the lowest layers of the atmosphere and can also improve the accuracy of the greenhouse gas concentration budgets highly depending on MLH. Therefore, during the next years, operational MLH monitoring networks of LIDAR ceilometers are established around the world, and in particular in Europe. To perform this task, different algorithms have been developed to retrieve the MLH from the ceilometer measurements. However, under specific atmospheric conditions, these algorithms fail to retrieve a similar MLH than other remote sensing retrieval techniques. On the other hand, the ceilometers are sometimes located in places where no other remote sensing measurements are available to assess the accuracy of the MLH retrieved by the algorithm. In this context, the development of several MLH quality control flags based on the ceilometer measurements only is desirable to detect automatically the failure of the MLH retrieval algorithms without the support of additional measurements. In Belgium, in 2013, three new ceilometers (Vaisala CL51) will be installed by the Royal Meteorological Institute of Belgium (RMI) in addition to the one in Uccle (Belgium) that has already been installed since May 2011. RMI developed its own MLH retrieval algorithm based on the gradient and variance methods. The computation of several quality flags will be presented. In this work, an assessment of these quality flags is made by comparing the MLH retrieved by ceilometer measurements with the MLH retrieved by radio-sounding and the boundary layer height (BLH) directly computed by the ECMWF and the ALARO7

  11. A multi-decadal history of biomass burning plume heights identified using aerosol index measurements

    Directory of Open Access Journals (Sweden)

    H. Guan

    2010-07-01

    Full Text Available We have quantified the relationship between Aerosol Index (AI measurements and plume height for young biomass burning plumes using coincident Ozone Monitoring Instrument (OMI and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO measurements. This linear relationship allows the determination of high-altitude plumes wherever AI data are available, and it provides a data set for validating global fire plume heights in chemistry transport models. We find that all plumes detected from June 2006 to February 2009 with an AI value ≥9 are located at altitudes higher than 5 km. Older high-altitude plumes have lower AI values than young plumes at similar altitudes. We have examined available AI data from the OMI and TOMS instruments (1978–2009 and find that large AI plumes occur more frequently over North America than over Australia or Russia/Northeast Asia. According to the derived relationship, during this time interval, 181 plumes, in various stages of their evolution, reached altitudes above 8 km.

  12. Benchmarking flood models from space in near real-time: accommodating SRTM height measurement errors with low resolution flood imagery

    Science.gov (United States)

    Schumann, G.; di Baldassarre, G.; Alsdorf, D.; Bates, P. D.

    2009-04-01

    In February 2000, the Shuttle Radar Topography Mission (SRTM) measured the elevation of most of the Earth's surface with spatially continuous sampling and an absolute vertical accuracy greater than 9 m. The vertical error has been shown to change with topographic complexity, being less important over flat terrain. This allows water surface slopes to be measured and associated discharge volumes to be estimated for open channels in large basins, such as the Amazon. Building on these capabilities, this paper demonstrates that near real-time coarse resolution radar imagery of a recent flood event on a 98 km reach of the River Po (Northern Italy) combined with SRTM terrain height data leads to a water slope remarkably similar to that derived by combining the radar image with highly accurate airborne laser altimetry. Moreover, it is shown that this space-borne flood wave approximation compares well to a hydraulic model and thus allows the performance of the latter, calibrated on a previous event, to be assessed when applied to an event of different magnitude in near real-time. These results are not only of great importance to real-time flood management and flood forecasting but also support the upcoming Surface Water and Ocean Topography (SWOT) mission that will routinely provide water levels and slopes with higher precision around the globe.

  13. Long-Term Monitoring of Regional Sea Surface Height Variability Using High-Resolution Satellite Altimetry

    Science.gov (United States)

    Rice, A. E.; Crout, R. L.

    2017-12-01

    Shallow water altimetry is an emerging field that in recent years has rapidly gained attention for both the numerous applications it can offer to the oceanographic community (e.g. assessment of climate change impacts to the coastal zone; quantification of sea state etc.) and, depending on the altimeter used, for the wealth of available historical data that can be employed for climatological studies. In this study we focus on the long-term analysis of regional sea surface height anomaly (SSHA) variability over the mid and outer shelf (≥ 16 km from the coast) for 18 selected coastal altimeter tracks located on the east coast of the US and Asia for a period of eight years (294 passes from July 2008 to July 2016) using Jason-2 20 Hz altimeter data from the L2 AVISO-PISTACH experimental products. After implementing geophysical corrections to the raw altimeter range, signal noise in the individual SSH passes was reduced by applying a median filter followed by a 60-point (18 km) low-pass filter as in Birol and Delebeque (2014). Since individual altimeter passes did not cease to collect data at the same distance from the coastline, a nearest-point-to-land (NPTL) was determined for each track for statistical analysis of the data. NPTL time series and SSHA envelopes, computed by subtracting mean SSHAs from individual passes, were used for the analysis. A comparison of wind and water level gauge data to a US east coast track reveals correlation between SSHA and winds and a relationship to subtidal water level frequencies. Time series of NPTL for all tracks show intra-annual and inter and intra-seasonal variability, with higher and lower water levels linked to seasons. Lastly, envelope plots display higher SSHA variability over the mid shelf than the outer shelf, revealing the location and magnitude (up to 0.5 m water level differences) of setup and set down occurrences. Various products derived from the analysis that are useful for oceanographic operations, including water

  14. Temporal and spatial characteristics of sea surface height variability in the North Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    D. Cromwell

    2006-01-01

    Full Text Available We investigate the spatial and temporal variability of sea surface height (SSH in the North Atlantic basin using satellite altimeter data from October 1992–January 2004. Our primary aim is to provide a detailed description of such variability, including that associated with propagating signals. We also investigate possible correlations between SSH variability and atmospheric pressure changes as represented by climate indices. We first investigate interannual SSH variations by deriving the complex empirical orthogonal functions (CEOFs of altimeter data lowpass-filtered at 18 months. We determine the spatial structure of the leading four modes (both in amplitude and phase and also the associated principal component (PC time series. Using wavelet analysis we derive the time-varying spectral density of the PCs, revealing when particular modes were strongest between 1992–2004. The spatial pattern of the leading CEOF, comprising 30% of the total variability, displays a 5-year periodicity in phase; signal propagation is particularly marked in the Labrador Sea. The second mode, with a dominant 3-year signal, has strong variability in the eastern basin. Secondly, we focus on the Azores subtropical frontal zone. The leading mode (35% is strong in the south and east of this region with strong variations at 3- and 5-year periods. The second mode (21% has a near-zonal band of low variance between  22°–27° N, sandwiched between two regions of high variance. Thirdly, we lowpass filter the altimeter data at a cutoff of 30 days, instead of 18 months, in order to retain signals associated with propagating baroclinic Rossby waves and/or eddies. The leading mode is the annual steric signal, around 46% of the SSH variability. The third and fourth CEOFs,  11% of the remaining variability, are associated with westward propagation which is particularly dominant in a "waveband" between 32°–36° N. For all three cases considered above, no significant cross

  15. Calibration of areal surface topography measuring instruments

    Science.gov (United States)

    Seewig, J.; Eifler, M.

    2017-06-01

    The ISO standards which are related to the calibration of areal surface topography measuring instruments are the ISO 25178-6xx series which defines the relevant metrological characteristics for the calibration of different measuring principles and the ISO 25178-7xx series which defines the actual calibration procedures. As the field of areal measurement is however not yet fully standardized, there are still open questions to be addressed which are subject to current research. Based on this, selected research results of the authors in this area are presented. This includes the design and fabrication of areal material measures. For this topic, two examples are presented with the direct laser writing of a stepless material measure for the calibration of the height axis which is based on the Abbott- Curve and the manufacturing of a Siemens star for the determination of the lateral resolution limit. Based on these results, as well a new definition for the resolution criterion, the small scale fidelity, which is still under discussion, is presented. Additionally, a software solution for automated calibration procedures is outlined.

  16. Tropical cyclone cloud‐top height and vertical temperature structure detection using GPS radio occultation measurements

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Ho, Shu‐Peng; Randel, William

    2013-01-01

    The accurate determination of tropical cyclone (TC) cloud-top height and its vertical thermal structure using the GPS radio occultation (RO) technique is demonstrated in this study. Cloud-top heights are determined by using the bending angle anomaly and the temperature anomaly profiles during......-derived inversion heights and those from radiosonde temperature profiles is approximately 500 m. Results show that, while cloud-top height detected from nadir-viewing satellites can be easily biased by a few kilometers, the biases of RO-derived cloud-top height are within ~500 m....

  17. The Algorithm Theoretical Basis Document for the Derivation of Range and Range Distributions from Laser Pulse Waveform Analysis for Surface Elevations, Roughness, Slope, and Vegetation Heights

    Science.gov (United States)

    Brenner, Anita C.; Zwally, H. Jay; Bentley, Charles R.; Csatho, Bea M.; Harding, David J.; Hofton, Michelle A.; Minster, Jean-Bernard; Roberts, LeeAnne; Saba, Jack L.; Thomas, Robert H.; hide

    2012-01-01

    The primary purpose of the GLAS instrument is to detect ice elevation changes over time which are used to derive changes in ice volume. Other objectives include measuring sea ice freeboard, ocean and land surface elevation, surface roughness, and canopy heights over land. This Algorithm Theoretical Basis Document (ATBD) describes the theory and implementation behind the algorithms used to produce the level 1B products for waveform parameters and global elevation and the level 2 products that are specific to ice sheet, sea ice, land, and ocean elevations respectively. These output products, are defined in detail along with the associated quality, and the constraints, and assumptions used to derive them.

  18. The Influence of Structure Heights and Opening Angles of Micro- and Nanocones on the Macroscopic Surface Wetting Properties

    Science.gov (United States)

    Schneider, Ling; Laustsen, Milan; Mandsberg, Nikolaj; Taboryski, Rafael

    2016-01-01

    We discuss the influence of surface structure, namely the height and opening angles of nano- and microcones on the surface wettability. We show experimental evidence that the opening angle of the cones is the critical parameter on sample superhydrophobicity, namely static contact angles and roll-off angles. The textured surfaces are fabricated on silicon wafers by using a simple one-step method of reactive ion etching at different processing time and gas flow rates. By using hydrophobic coating or hydrophilic surface treatment, we are able to switch the surface wettability from superhydrophilic to superhydrophobic without altering surface structures. In addition, we show examples of polymer replicas (polypropylene and poly(methyl methacrylate) with different wettability, fabricated by injection moulding using templates of the silicon cone-structures. PMID:26892169

  19. The Influence of Structure Heights and Opening Angles of Micro- and Nanocones on the Macroscopic Surface Wetting Properties

    DEFF Research Database (Denmark)

    Sun, Ling; Laustsen, Milan; Mandsberg, Nikolaj

    2016-01-01

    -off angles. The textured surfaces are fabricated on silicon wafers by using a simple one-step method of reactive ion etching at different processing time and gas flow rates. By using hydrophobic coating or hydrophilic surface treatment, we are able to switch the surface wettability from superhydrophilic......We discuss the influence of surface structure, namely the height and opening angles of nano-and microcones on the surface wettability. We show experimental evidence that the opening angle of the cones is the critical parameter on sample superhydrophobicity, namely static contact angles and roll...... to superhydrophobic without altering surface structures. In addition, we show examples of polymer replicas (polypropylene and poly(methyl methacrylate) with different wettability, fabricated by injection moulding using templates of the silicon cone-structures....

  20. A sensitivity-based approach to optimize the surface treatment of a low-height tramway noise barrier

    Science.gov (United States)

    Jolibois, Alexandre

    Transportation noise has become a main nuisance in urban areas, in the industrialized world and across the world, to the point that according to the World Health Organization 65% of the European population is exposed to excessive noise and 20% to night-time levels that may harm their health. There is therefore a need to find new ways to mitigate transportation noise in urban areas. In this work, a possible device to achieve this goal is studied: a low-height noise barrier. It consists of a barrier typically less than one meter high placed close to the source, designed to decrease significantly the noise level for nearby pedestrians and cyclists. A numerical method which optimizes the surface treatment of a low-height barrier in order to increase its insertion loss is presented. Tramway noise barriers are especially studied since the noise sources are in this case close to the ground and would be attenuated more by the barrier. The acoustic behavior of the surface treatment is modeled via its admittance. It can be itself described by a few parameters (flow resistivity, geometrical dimensions...), which can then be optimized. It is proposed to couple porous layers and micro-perforated panel (MPP) resonators in order to take advantage of their different acoustic properties. Moreover, the optimization is achieved using a sensitivity-based method, since in this framework the gradient of the attenuation can be evaluated accurately and efficiently. Several shapes are considered: half-cylinder, quarter-cylinder, straight wall, T-shape and square shape. In the case of a half-cylindrical geometry, a semi-analytical solution for the sound field in terms of a series of cylindrical waves is derived, which simplifies the sensitivity calculation and optimization process. The boundary element method (BEM) is used to evaluate the attenuation for the remaining shapes, and in this case the sensitivity is evaluated using the adjoint state approach. For all considered geometries, it is

  1. Using eddy geopotential height to measure the western North Pacific subtropical high in a warming climate

    Science.gov (United States)

    He, Chao; Lin, Ailan; Gu, Dejun; Li, Chunhui; Zheng, Bin; Wu, Bo; Zhou, Tianjun

    2018-01-01

    The western North Pacific subtropical high (WNPSH) is crucial to the East Asian summer climate, and geopotential height ( H) is widely used to measure the WPNSH. However, a rapidly rising trend of H in the future is projected by the models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Diagnoses based on the hypsometric equation suggest that more than 80% of the rise in H are attributable to zonal uniform warming. Because circulation is determined by the gradient of H rather than its absolute magnitude, the spatially uniform rising trend of H gives rise to difficulties when measuring the WNPSH with H. These difficulties include an invalid western boundary of WNPSH in the future and spurious information regarding long-term trends and interannual variability of WNPSH. Using CMIP5 model simulations and reanalysis data, the applicability of a metric based on eddy geopotential height ( H e ) to the warming climate is investigated. The results show that the H e metric outperforms the H metric under warming climate conditions. First, the mean state rainfall- H e relationship is more robust than the rainfall- H relationship. Second, the area, intensity, and western boundary indices of WNPSH can be effectively defined by the H e = 0-m contour in future warming climate scenarios without spurious trends. Third, the interannual variability of East Asian summer rainfall is more closely related to the H e -based WNPSH indices. We recommend that the H e metric be adopted as an operational metric on the WNPSH under the current warming climate.

  2. Remote Sensing Measures Restoration Successes, but Canopy Heights Lag in Restoring Floodplain Vegetation

    Directory of Open Access Journals (Sweden)

    Samantha K. Dawson

    2016-06-01

    Full Text Available Wetlands worldwide are becoming increasingly degraded, and this has motivated many attempts to manage and restore wetland ecosystems. Restoration actions require a large resource investment, so it is critical to measure the outcomes of these management actions. We evaluated the restoration of floodplain wetland vegetation across a chronosequence of land uses, using remote sensing analyses. We compared the Landsat-based fractional cover of restoration areas with river red gum and lignum reference communities, which functioned as a fixed target for restoration, over three time periods: (i before agricultural land use (1987–1997; (ii during the peak of agricultural development (2004–2007; and (iii post-restoration of flooding (2010–2015. We also developed LiDAR-derived canopy height models (CHMs for comparison over the second and third time periods. Inundation was crucial for restoration, with many fields showing little sign of similarity to target vegetation until after inundation, even if agricultural land uses had ceased. Fields cleared or cultivated for only one year had greater restoration success compared to areas cultivated for three or more years. Canopy height increased most in the fields that were cleared and cultivated for a short duration, in contrast to those cultivated for >12 years, which showed few signs of recovery. Restoration was most successful in fields with a short development duration after the intervention, but resulting dense monotypic stands of river cooba require future monitoring and possibly intervention to prevent sustained dominance. Fields with intensive land use histories may need to be managed as alternative, drier flood-dependent vegetation communities, such as black box (Eucalyptus largiflorens grasslands. Remotely-sensed data provided a powerful measurement technique for tracking restoration success over a large floodplain.

  3. Determination of Mean Dynamic Topography (MDT) to Bridge Geoid and Mean Sea Surface Height (SSH) with a New Elliptic Equation

    Science.gov (United States)

    Chu, P. C.

    2016-12-01

    Mean dynamic topography (MDT, η) bridges the geoid and the mean sea surface (from satellite altimetry) and constrains large scale surface geostrophic circulations. It can be estimated from either satellite or underwater ocean temperature (T) and salinity (S) data. Satellite altimeter measures sea surface height (SSH) with high precision and unique resolution above a reference ellipsoid (not geoid). Two Gravity Recovery and Climate Experiment (GRACE) satellites launched in 2002, provide data to compute the marine geoid [called the GRACE Gravity Model (GGM)] (see website: http://www.csr.utexas.edu/grace/). The MDT is the difference of altimetry-derived mean SSH and the mean marine geoid (using GGM or pre-GRACE gravity model such as EGM96). A major difficulty arises that the spatial variations in mean SSH and marine geoid are approximately two orders of magnitude larger than the spatial variations in η.The second approach (using T, Sdata) is based on geostrophic balance, which is at the minimum energy state in the linear Boussinesq primitive equations with conservation of potential vorticity. In this paper, a new elliptic equation, -[∂x(gh/f2)∂xη+∂y(gh/f2)∂yη]+η = (g/f2)(∂C/∂x-∂B/∂y)is derived to determine MDT with H the water depth, g the gravitational acceleration, and coefficients (B, C) depend on 3D mean temperature (T) and salinity (S) data. Numerical approach transforms the elliptic equation into a set of well-posed linear algebraic equations of η at grid points. The solution for the North Atlantic Ocean (100oW-6oW, 7oN-72oN) on 1oX1ogrids with the coefficients (B, C) calculated from the three-dimensional (T, S) data of the NOAA National Centers for Environmental Information (NCEI) World Ocean Atlas 2013 version 2 (http://www.nodc.noaa.gov/OC5/woa13/woa13data.html) and H from the NOAA ETOPO5 (https://www.ngdc.noaa.gov/mgg/fliers/93mgg01.html), compares well with the difference (also considered as the MDT) between the time-averaged SSH and

  4. Body height estimation from post-mortem CT femoral F1 measurements in a contemporary Swiss population.

    Science.gov (United States)

    Zech, Wolf-Dieter; Näf, Maya; Siegmund, Frank; Jackowski, Christian; Lösch, Sandra

    2016-03-01

    The present study aimed at the comparison of body height estimations from cadaver length with body height estimations according to Trotter and Gleser (1952) and Penning and Riepert (2003) on the basis of femoral F1 section measurements in post-mortem computed tomography (PMCT) images. In a post-mortem study in a contemporary Swiss population (226 corpses: 143 males (mean age: 53 ± 17 years) and 83 females (mean age: 61 ± 20 years)) femoral F1 measurements (403 femora: 199 right and 204 left; 177 pairs) were conducted in PMCT images and F1 was used for body height estimation using the equations after Trotter and Gleser (1952, "American Whites"), and Penning and Riepert (2003). The mean observed cadaver length was 176.6 cm in males and 163.6 cm in females. Mean measured femoral length F1 was 47.5 cm (males) and 44.1cm (females) respectively. Comparison of body height estimated from PMCT F1 measurements with body height calculated from cadaver length showed a close congruence (mean difference less than 0.95 cm in males and less than 1.99 cm in females) for equations both applied after Penning and Riepert and Trotter and Gleser. Femoral F1 measurements in PMCT images are very accurate, reproducible and feasible for body height estimation of a contemporary Swiss population when using the equations after Penning and Riepert (2003) or Trotter and Gleser (1952). Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Mississippi River and Sea Surface Height Effects on Oil Slick Migration

    Science.gov (United States)

    Falcini, Frederico; Jerolmack, Douglas J.; Buongiorno Nardelli, Bruno

    2012-01-01

    Millions of barrels of oil escaped into the Gulf of Mexico (GoM) after the 20 April, 2010 explosion of Deepwater Horizon (DH). Ocean circulation models were used to forecast oil slick migration in the GoM, however such models do not explicitly treat the effects of secondary eddy-slopes or Mississippi River (MR) hydrodynamics. Here we report oil front migration that appears to be driven by sea surface level (SSL) slopes, and identify a previously unreported effect of the MR plume: under conditions of relatively high river discharge and weak winds, a freshwater mound can form around the MR Delta. We performed temporal oil slick position and altimeter analysis, employing both interpolated altimetry data and along-track measurements for coastal applications. The observed freshwater mound appears to have pushed the DH oil slick seaward from the Delta coastline. We provide a physical mechanism for this novel effect of the MR, using a two-layer pressure-driven flow model. Results show how SSL variations can drive a cross-slope migration of surface oil slicks that may reach velocities of order km/day, and confirm a lag time of order 5–10 days between mound formation and slick migration, as observed form the satellite analysis. Incorporating these effects into more complex ocean models will improve forecasts of slick migration for future spills. More generally, large SSL variations at the MR mouth may also affect the dispersal of freshwater, nutrients and sediment associated with the MR plume. PMID:22558317

  6. Modeling Caribbean tree stem diameters from tree height and crown width measurements

    Science.gov (United States)

    Thomas Brandeis; KaDonna Randolph; Mike Strub

    2009-01-01

    Regression models to predict diameter at breast height (DBH) as a function of tree height and maximum crown radius were developed for Caribbean forests based on data collected by the U.S. Forest Service in the Commonwealth of Puerto Rico and Territory of the U.S. Virgin Islands. The model predicting DBH from tree height fit reasonably well (R2 = 0.7110), with...

  7. Body Height and Its Estimation Utilizing Arm Span Measurements in Bosnian and Herzegovinian Adults

    OpenAIRE

    Stevo Popovic; Dusko Bjelica; Gabriela Doina Tanase; Rajko Milašinović

    2015-01-01

    Anthropologists recognized the tallness of nations in the Dinaric Alps long time ago. As the modern Bosnian and Herzegovinian fall more into the Dinaric racial classification, the purpose of this study was to examine the body height in Bosnian and Herzegovinian adults as well as the relationship between arm span as an alternative to estimating the body height and body height, which vary in different ethnic and racial groups. The nature and scope of this study analyzes 212 students (178 men, a...

  8. Determination of the optimized single-layer ionospheric height for electron content measurements over China

    Science.gov (United States)

    Li, Min; Yuan, Yunbin; Zhang, Baocheng; Wang, Ningbo; Li, Zishen; Liu, Xifeng; Zhang, Xiao

    2018-02-01

    The ionosphere effective height (IEH) is a very important parameter in total electron content (TEC) measurements under the widely used single-layer model assumption. To overcome the requirement of a large amount of simultaneous vertical and slant ionospheric observations or dense "coinciding" pierce points data, a new approach comparing the converted vertical TEC (VTEC) value using mapping function based on a given IEH with the "ground truth" VTEC value provided by the combined International GNSS Service Global Ionospheric Maps is proposed for the determination of the optimal IEH. The optimal IEH in the Chinese region is determined using three different methods based on GNSS data. Based on the ionosonde data from three different locations in China, the altitude variation of the peak electron density (hmF2) is found to have clear diurnal, seasonal and latitudinal dependences, and the diurnal variation of hmF2 varies from approximately 210 to 520 km in Hainan. The determination of the optimal IEH employing the inverse method suggested by Birch et al. (Radio Sci 37, 2002. doi: 10.1029/2000rs002601) did not yield a consistent altitude in the Chinese region. Tests of the method minimizing the mapping function errors suggested by Nava et al. (Adv Space Res 39:1292-1297, 2007) indicate that the optimal IEH ranges from 400 to 600 km, and the height of 450 km is the most frequent IEH at both high and low solar activities. It is also confirmed that the IEH of 450-550 km is preferred for the Chinese region instead of the commonly adopted 350-450 km using the determination method of the optimal IEH proposed in this paper.

  9. Mississippi River and sea surface height effects on oil slick migration.

    Directory of Open Access Journals (Sweden)

    Frederico Falcini

    Full Text Available Millions of barrels of oil escaped into the Gulf of Mexico (GoM after the 20 April, 2010 explosion of Deepwater Horizon (DH. Ocean circulation models were used to forecast oil slick migration in the GoM, however such models do not explicitly treat the effects of secondary eddy-slopes or Mississippi River (MR hydrodynamics. Here we report oil front migration that appears to be driven by sea surface level (SSL slopes, and identify a previously unreported effect of the MR plume: under conditions of relatively high river discharge and weak winds, a freshwater mound can form around the MR Delta. We performed temporal oil slick position and altimeter analysis, employing both interpolated altimetry data and along-track measurements for coastal applications. The observed freshwater mound appears to have pushed the DH oil slick seaward from the Delta coastline. We provide a physical mechanism for this novel effect of the MR, using a two-layer pressure-driven flow model. Results show how SSL variations can drive a cross-slope migration of surface oil slicks that may reach velocities of order km/day, and confirm a lag time of order 5-10 days between mound formation and slick migration, as observed form the satellite analysis. Incorporating these effects into more complex ocean models will improve forecasts of slick migration for future spills. More generally, large SSL variations at the MR mouth may also affect the dispersal of freshwater, nutrients and sediment associated with the MR plume.

  10. Two-method measurement for adolescent obesity epidemiology: reducing the bias in self-report of height and weight.

    Science.gov (United States)

    Drake, Keith M; Longacre, Meghan R; Dalton, Madeline A; Langeloh, Gail; Peterson, Karen E; Titus, Linda J; Beach, Michael L

    2013-09-01

    Despite validation studies demonstrating substantial bias, epidemiologic studies typically use self-reported height and weight as primary measures of body mass index because of feasibility and resource limitations. To demonstrate a method for calculating accurate and precise estimates that use body mass index when objectively measuring height and weight in a full sample is not feasible. As part of a longitudinal study of adolescent health, 1,840 adolescents (ages 12-18) self-reported their height and weight during telephone surveys. Height and weight was measured for 407 of these adolescents. Sex-specific, age-adjusted obesity status was calculated from self-reported and from measured height and weight. Prevalence and predictors of obesity were estimated using self-reported data, measured data, and multiple imputation (of measured data). Among adolescents with self-reported and measured data, the obesity prevalence was lower when using self-report compared with actual measurements (p obesity prevalence from multiple imputation (20%) was much closer to estimates based solely on measured data (20%) compared with estimates based solely on self-reported data (12%), indicating improved accuracy. In multivariate models, estimates of predictors of obesity were more accurate and approximately as precise (similar confidence intervals) as estimates based solely on self-reported data. The two-method measurement design offers researchers a technique to reduce the bias typically inherent in self-reported height and weight without needing to collect measurements on the full sample. This technique enhances the ability to detect real, statistically significant differences, while minimizing the need for additional resources. Copyright © 2013 Society for Adolescent Health and Medicine. All rights reserved.

  11. On the use of double differences in inversion of surface movement measurements

    NARCIS (Netherlands)

    Fokker, P.A.; Thienen-Visser, K. van

    2015-01-01

    Surface movement data can be used in data assimilation or inversion exercises to improve the level of knowledge of a compacting reservoir. We have designed, implemented and tested a new algorithm that uses measured optical height differences directly, without having to translate them to heights with

  12. Measurement of kyphosis and vertebral body height loss in traumatic spine fractures: an international study.

    Science.gov (United States)

    Sadiqi, Said; Verlaan, Jorrit-Jan; Lehr, A Mechteld; Chapman, Jens R; Dvorak, Marcel F; Kandziora, Frank; Rajasekaran, S; Schnake, Klaus J; Vaccaro, Alexander R; Oner, F Cumhur

    2017-05-01

    To investigate whether wide variations are seen in the measurement techniques preferred by spine surgeons around the world to assess traumatic fracture kyphosis and vertebral body height loss (VBHL). An online survey was conducted at two time points among an international community of spine trauma experts from all world regions. The first survey (TL-survey) focused on the thoracic, thoracolumbar and lumbar spine, the second survey (C-survey) on the subaxial cervical spine. Participants were asked to indicate which measurement technique(s) they used for measuring kyphosis and VBHL. Descriptive statistics, frequency analysis and the Fisher exact test were used to analyze the responses. Of the 279 invited experts, 107 (38.4 %) participated in the TL-survey, and 108 (38.7 %) in the C-survey. The Cobb angle was the most frequently used for all spine regions to assess kyphosis (55.6-75.7 %), followed by the wedge angle and adjacent endplates method. Concerning VBHL, the majority of the experts used the vertebral body compression ratio in all spine regions (51.4-54.6 %). The most frequently used combination for kyphosis was the Cobb and wedge angles. Considerable differences were observed between the world regions, while fewer differences were seen between surgeons with different degrees of experience. This study identified worldwide variations in measurement techniques preferred by treating spine surgeons to assess fracture kyphosis and VBHL in spine trauma patients. These results establish the importance of standardizing assessment parameters in spine trauma care, and can be taken into account to further investigate these radiographic parameters.

  13. Validity of parent-reported weight and height of preschool children measured at home or estimated without home measurement: a validation study

    Directory of Open Access Journals (Sweden)

    Cox Bianca

    2011-07-01

    Full Text Available Abstract Background Parental reports are often used in large-scale surveys to assess children's body mass index (BMI. Therefore, it is important to know to what extent these parental reports are valid and whether it makes a difference if the parents measured their children's weight and height at home or whether they simply estimated these values. The aim of this study is to compare the validity of parent-reported height, weight and BMI values of preschool children (3-7 y-old, when measured at home or estimated by parents without actual measurement. Methods The subjects were 297 Belgian preschool children (52.9% male. Participation rate was 73%. A questionnaire including questions about height and weight of the children was completed by the parents. Nurses measured height and weight following standardised procedures. International age- and sex-specific BMI cut-off values were employed to determine categories of weight status and obesity. Results On the group level, no important differences in accuracy of reported height, weight and BMI were identified between parent-measured or estimated values. However, for all 3 parameters, the correlations between parental reports and nurse measurements were higher in the group of children whose body dimensions were measured by the parents. Sensitivity for underweight and overweight/obesity were respectively 73% and 47% when parents measured their child's height and weight, and 55% and 47% when parents estimated values without measurement. Specificity for underweight and overweight/obesity were respectively 82% and 97% when parents measured the children, and 75% and 93% with parent estimations. Conclusions Diagnostic measures were more accurate when parents measured their child's weight and height at home than when those dimensions were based on parental judgements. When parent-reported data on an individual level is used, the accuracy could be improved by encouraging the parents to measure weight and height

  14. X-ray imaging with amorphous selenium: Pulse height measurements of avalanche gain fluctuations

    International Nuclear Information System (INIS)

    Lui, Brian J. M.; Hunt, D. C.; Reznik, A.; Tanioka, K.; Rowlands, J. A.

    2006-01-01

    Avalanche multiplication in amorphous selenium (a-Se) can provide a large, adjustable gain for active matrix flat panel imagers (AMFPI), enabling quantum noise limited x-ray imaging during both radiography and fluoroscopy. In the case of direct conversion AMFPI, the multiplication factor for each x ray is a function of its depth of interaction, and the resulting variations in gain can reduce the detective quantum efficiency (DQE) of the system. An experimental method was developed to measure gain fluctuations by analyzing images of individual x rays that were obtained using a video camera with an a-Se target operated in avalanche mode. Pulse height spectra (PHS) of the charge produced per x ray were recorded for monoenergetic 30.9, 49.4, and 73.8 keV x-ray sources. The rapid initial decay and long tail of each PHS can be explained by a model in which positive charge dominates the initiation of avalanche. The Swank information factor quantifies the effect of gain fluctuation on DQE and was calculated from the PHS. The information factor was found to be 0.5 for a 25 μm a-Se layer with a maximum gain of ∼300. Changing the energy of the incident x ray influenced the range of the primary photoelectron and noticeably affected the tail of the experimental PHS, but did not significantly change the avalanche Swank factor

  15. Body Height and Its Estimation Utilizing Arm Span Measurements of both Gender Adolescents from Central Region in Kosovo

    Directory of Open Access Journals (Sweden)

    Fitim Arifi

    2017-06-01

    Full Text Available This study is based on measurements of Central region Kosovar adolescents. The aim of this study was to examine the Body Height of adolescents from Central region as well relationship between arm span and Body Height in both Kosovar genders. A total measured subject participated in this research was 193 out of which (93 girls and 100 boys, females average of age is 18.15±0.35 years old (range 18-20 years and for male 18.26±0.44 years old (range 18-20 years. The anthropometric measurements were done by trained people and were taken according to the ISAK manual. Relationship between Body Height and arm span has been analyzed by the simple correlation coefficient at a 95% confidence interval. The linear regression analysis was carried out to examine extent to which arm span can reliably predict of Body Height. Statistical importance was placed at level p<0.05. As a result anthropometric measurements for both sexes showed that the average of Body Height for boys adolescents from Central region are 180.62±5.88 centimeters and have the arm span average of 181.36±7.08 centimeters, while girls from Central 166.77±4.71 centimeters tall, and have the arm span average of 167.08±5.03 centimeters. The results have shown that the arm span was estimated as a reliable indicator of Body Height assessment to the both genders adolescents from Central region of Kosovo population. This study also confirms the necessity for developing separate height models for each region in Kosovo.

  16. Sea level height, sea surface temperature, and tuna yields in the Panama bight during El Niño

    Directory of Open Access Journals (Sweden)

    M. J. Pedraza

    2006-01-01

    Full Text Available Between 1988 and 1998, annual tuna landings at Buenaventura (Colombian Pacific are correlated with the sea surface temperature in the central Equatorial Pacific (r=0.78, p<0.05 and the sea level height at Buenaventura (r=0.76, p<0.05 and Balboa (Panama (r=0.79, p<0.05. Seasonal oceanic upwelling is forced by the Panama wind jet, which may favour oceanic fisheries such as tuna. Here we first apply a bivariate correlation method (Pyper and Peterman, 1994 and then a multivariate approach (principal components analysis or PCA to investigate the relationships of these environmental variables with landings. With the first method, we find that landing is best correlated with the sea surface temperature in the Niño 3 region, whereas the other relationships are less clear. In contrast, with PCA we find that PC1 explains 90.6% of the total variance and suggests that sea surface temperature plays a major role in determining tuna availability in the area (especially during El Niño events. Since PC2 is mainly correlated with sea level height at Balboa but only represents 6.8% of the total variance, we suggest that oceanic upwelling effects on tuna landings at Buenaventura are not significant at interannual scales.

  17. Application of Displacement Height and Surface Roughness Length to Determination Boundary Layer Development Length over Stepped Spillway

    Directory of Open Access Journals (Sweden)

    Xiangju Cheng

    2014-12-01

    Full Text Available One of the most uncertain parameters in stepped spillway design is the length (from the crest of boundary layer development. The normal velocity profiles responding to the steps as bed roughness are investigated in the developing non-aerated flow region. A detailed analysis of the logarithmic vertical velocity profiles on stepped spillways is conducted through experimental data to verify the computational code and numerical experiments to expand the data available. To determine development length, the hydraulic roughness and displacement thickness, along with the shear velocity, are needed. This includes determining displacement height d and surface roughness length z0 and the relationship of d and z0 to the step geometry. The results show that the hydraulic roughness height ks is the primary factor on which d and z0 depend. In different step height, step width, discharge and intake Froude number, the relations d/ks = 0.22–0.27, z0/ks = 0.06–0.1 and d/z0 = 2.2–4 result in a good estimate. Using the computational code and numerical experiments, air inception will occur over stepped spillway flow as long as the Bauer-defined boundary layer thickness is between 0.72 and 0.79.

  18. Kinect Who’s Coming - Applying Kinect to Human Body Height Measurement to Improve Character Recognition Performance

    Directory of Open Access Journals (Sweden)

    Hau-Wei Lee

    2015-05-01

    Full Text Available A great deal of relevant research on character recognition has been carried out, but a certain amount of time is needed to compare faces from a large database. The Kinect is able to obtain three-dimensional coordinates for an object (x & y axes and depth, and in recent years research on its applications has expanded from use in gaming to that of image measurement. This study uses Kinect skeleton information to conduct body height measurements with the aim of improving character recognition performance. Time spent searching and comparing characters is reduced by creating height categories. The margin of error for height used in this investigation was ± 5 cm; therefore, face comparisons were only executed for people in the database within ±5 cm of the body height measured, reducing the search time needed. In addition, using height and facial features simultaneously to conduct character recognition can also reduce the frequency of mistaken recognition. The Kinect was placed on a rotary stage and the position of the head on the body frame was used to conduct body tracking. Body tracking can be used to reduce image distortion caused by the lens of the Kinect. EmguCV was used for image processing and character recognition. The methods proposed in this study can be used in public safety, student attendance registration, commercial VIP recognition and many others.

  19. Use of self-reported measures of height, weight and body mass index in a rural population of Northeast Brazil.

    Science.gov (United States)

    Martins, Poliana Cardoso; de Carvalho, Maria Bernadete; Machado, Carla Jorge

    2015-01-01

    To assess the validity of using self-reported anthropometric data for diagnosis of nutritional status of adults in a rural population of northeast Brazil. A population-based survey was conducted on a sample of 797 individuals aged 18 years or more. The proportion of individuals who knew their anthropometric measures was calculated. For agreement analysis between those who reported their measures the following indicators were obtained: differences between averages (weight, height, body mass index), intra-class correlation coefficient (ICC), Kappa statistic, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (VPN). Bland-Altman graphics were also obtained. More than half of the respondents (58.5%) did not know their weight or height. Weight was the most known measure among all. The magnitude of the mean difference for weight, height and body mass index (BMI) (0.43 kg, 0.31 cm, 0.32 kg/m2, respectively) was small, indicating good agreement, with a trend toward overestimation. ICC for weight, height and BMI were 0.96; 0.60; and 0.53, respectively. Kappa statistic indicated good agreement in all strata. General measures of sensitivity, specificity, PPV and NPV were 84.2; 82; 90.7 and 71.3%, respectively. Elderly, those with low schooling and those who do not often weigh were less accurate on their measures. The use of self-reported measures should be done with caution in epidemiological studies in rural populations.

  20. Climatology of cloud-base height from long-term radiosonde measurements in China

    Science.gov (United States)

    Zhang, Yong; Zhang, Lejian; Guo, Jianping; Feng, Jinming; Cao, Lijuan; Wang, Yang; Zhou, Qing; Li, Liangxu; Li, Bai; Xu, Hui; Liu, Lin; An, Ning; Liu, Huan

    2018-02-01

    Clouds are critical to the global radiation budget and hydrological cycle, but knowledge is still poor concerning the observed climatology of cloud-base height (CBH) in China. Based on fine-resolution sounding observations from the China Radiosonde Network (CRN), the method used to estimate CBH was modified, and uncertainty analyses indicated that the CBH is good enough. The accuracy of CBH estimation is verified by the comparison between the sounding-derived CBHs and those estimated from the micro-pulse lidar and millimeter-wave cloud radar. As such, the CBH climatology was compiled for the period 2006-16. Overall, the CBH exhibits large geographic variability across China, at both 0800 Local Standard Time (LST) and 2000 LST, irrespective of season. In addition, the summertime cloud base tends to be elevated to higher altitudes in dry regions [i.e., Inner Mongolia and the North China Plain (NCP)]. By comparison, the Tibetan Plateau (TP), Pearl River Delta (PRD) and Sichuan Basin (SCB) have relatively low CBHs (cloud base tends to occur frequently (> 70%) over the TP, PRD and SCB. In contrast, at most sites over the Yangtze River Delta (YRD) and the NCP, about half the cloud belongs to the high-cloud category. The CBH does not exhibit marked diurnal variation in summer, throughout all CRN sites, probably due to the persistent cloud coverage caused by the East Asia Summer Monsson. To the best of our knowledge, this is the first CBH climatology produced from sounding measurements in China, and provides a useful reference for obtaining observational cloud base information.

  1. Measurements of Near Sea Surface Infrared Propagation

    National Research Council Canada - National Science Library

    Frost, Shaun

    1999-01-01

    .... Measurements have been made of the atmospheric infrared transmission near the sea surface. Spectral transmission profiles were measured for a number of ranges using a fourier transform spectrometer...

  2. The measurement of surface gravity

    International Nuclear Information System (INIS)

    Crossley, David; Hinderer, Jacques; Riccardi, Umberto

    2013-01-01

    This review covers basic theory and techniques behind the use of ground-based gravimetry at the Earth's surface. The orientation is toward modern instrumentation, data processing and interpretation for observing surface, land-based, time-variable changes to the geopotential. The instrumentation side is covered in some detail, with specifications and performance of the most widely used models of the three main types: the absolute gravimeters (FG5, A10 from Micro-g LaCoste), superconducting gravimeters (OSG, iGrav from GWR instruments), and the new generation of spring instruments (Micro-g LaCoste gPhone, Scintrex CG5 and Burris ZLS). A wide range of applications is covered, with selected examples from tides and ocean loading, atmospheric effects on gravity, local and global hydrology, seismology and normal modes, long period and tectonics, volcanology, exploration gravimetry, and some examples of gravimetry connected to fundamental physics. We show that there are only a modest number of very large signals, i.e. hundreds of µGal (10 −8 m s −2 ), that are easy to see with all gravimeters (e.g. tides, volcanic eruptions, large earthquakes, seasonal hydrology). The majority of signals of interest are in the range 0.1–5.0 µGal and occur at a wide range of time scales (minutes to years) and spatial extent (a few meters to global). Here the competing effects require a careful combination of different gravimeter types and measurement strategies to efficiently characterize and distinguish the signals. Gravimeters are sophisticated instruments, with substantial up-front costs, and they place demands on the operators to maximize the results. Nevertheless their performance characteristics such as drift and precision have improved dramatically in recent years, and their data recording ability and ruggedness have seen similar advances. Many subtle signals are now routinely connected with known geophysical effects such as coseismic earthquake displacements, post

  3. The measurement of surface gravity

    Science.gov (United States)

    Crossley, David; Hinderer, Jacques; Riccardi, Umberto

    2013-04-01

    This review covers basic theory and techniques behind the use of ground-based gravimetry at the Earth's surface. The orientation is toward modern instrumentation, data processing and interpretation for observing surface, land-based, time-variable changes to the geopotential. The instrumentation side is covered in some detail, with specifications and performance of the most widely used models of the three main types: the absolute gravimeters (FG5, A10 from Micro-g LaCoste), superconducting gravimeters (OSG, iGrav from GWR instruments), and the new generation of spring instruments (Micro-g LaCoste gPhone, Scintrex CG5 and Burris ZLS). A wide range of applications is covered, with selected examples from tides and ocean loading, atmospheric effects on gravity, local and global hydrology, seismology and normal modes, long period and tectonics, volcanology, exploration gravimetry, and some examples of gravimetry connected to fundamental physics. We show that there are only a modest number of very large signals, i.e. hundreds of µGal (10-8 m s-2), that are easy to see with all gravimeters (e.g. tides, volcanic eruptions, large earthquakes, seasonal hydrology). The majority of signals of interest are in the range 0.1-5.0 µGal and occur at a wide range of time scales (minutes to years) and spatial extent (a few meters to global). Here the competing effects require a careful combination of different gravimeter types and measurement strategies to efficiently characterize and distinguish the signals. Gravimeters are sophisticated instruments, with substantial up-front costs, and they place demands on the operators to maximize the results. Nevertheless their performance characteristics such as drift and precision have improved dramatically in recent years, and their data recording ability and ruggedness have seen similar advances. Many subtle signals are now routinely connected with known geophysical effects such as coseismic earthquake displacements, post-glacial rebound

  4. Slow and Steady: Ocean Circulation. The Influence of Sea Surface Height on Ocean Currents

    Science.gov (United States)

    Haekkinen, Sirpa

    2000-01-01

    The study of ocean circulation is vital to understanding how our climate works. The movement of the ocean is closely linked to the progression of atmospheric motion. Winds close to sea level add momentum to ocean surface currents. At the same time, heat that is stored and transported by the ocean warms the atmosphere above and alters air pressure distribution. Therefore, any attempt to model climate variation accurately must include reliable calculations of ocean circulation. Unlike movement of the atmosphere, movement of the ocean's waters takes place mostly near the surface. The major patterns of surface circulation form gigantic circular cells known as gyres. They are categorized according to their general location-equatorial, subtropical, subpolar, and polar-and may run across an entire ocean. The smaller-scale cell of ocean circulation is known' as an eddy. Eddies are much more common than gyres and much more difficult to track in computer simulations of ocean currents.

  5. Retrieving aerosol height from the oxygen A band: a fast forward operator and sensitivity study concerning spectral resolution, instrumental noise, and surface inhomogeneity

    Science.gov (United States)

    Hollstein, A.; Fischer, J.

    2014-05-01

    Hyperspectral radiance measurements in the oxygen A band are sensitive to the vertical distribution of atmospheric scatterers, which in principle allows the retrieval of aerosol height from future instruments like TROPOMI, OCO2, FLEX, and CarbonSat. Discussed in this paper is a fast and flexible forward operator for the simulation of hyperspectral radiances in the oxygen A band and, based on this scheme, a sensitivity study about the inversion quality of aerosol optical thickness, aerosol mean height, and aerosol type. The forward operator is based on a lookup table with efficient data compression based on principal component analysis. Linear interpolation and computation of partial derivatives is performed in the much smaller space of expansion coefficients rather than wavelength. Thus, this approach is computationally fast and, at the same time, memory efficient. The sensitivity study explores the impact of instrument design on the retrieval of aerosol optical thickness and aerosol height. Considered are signal to noise ratio, spectral resolution, and spectral sampling. Also taken into account are surface inhomogeneities and variations of the aerosol type.

  6. Climate change signal and uncertainty in CMIP5-based projections of global ocean surface wave heights

    Science.gov (United States)

    Wang, Xiaolan L.; Feng, Yang; Swail, Val R.

    2015-05-01

    This study uses the analysis of variance approaches to quantify the climate change signal and uncertainty in multimodel ensembles of statistical simulations of significant wave height (Hs), which are based on the CMIP5 historical, RCP4.5 and RCP8.5 forcing scenario simulations of sea level pressure. Here the signal of climate change refers to the temporal variations caused by the prescribed forcing. "Significant" means "significantly different from zero at 5% level." In a four-model ensemble of Hs simulations, the common signal—the signal that is simulated in all the four models—is found to strengthen over time. For the historical followed by RCP8.5 scenario, the common signal in annual mean Hs is found to be significant in 16.6% and 82.2% of the area by year 2005 and 2099, respectively. The global average of the variance proportion of the common signal increases from 0.75% in year 2005 to 12.0% by year 2099. The signal is strongest in the eastern tropical Pacific (ETP), featuring significant increases in both the annual mean and maximum of Hs in this region. The climate model uncertainty (i.e., intermodel variability) is significant nearly globally; its magnitude is comparable to or greater than that of the common signal in most areas, except in the ETP where the signal is much larger. In a 20-model ensemble of Hs simulations for the period 2006-2099, the model uncertainty is found to be significant globally; it is about 10 times as large as the variability between the RCP4.5 and RCP8.5 scenarios. The copyright line for this article was changed on 10 JUNE 2015 after original online publication.

  7. Self-reported and measured weight, height and body mass index (BMI) in Italy, the Netherlands and North America

    NARCIS (Netherlands)

    Krul, A.J.; Daanen, H.A.M.; Choi, H.

    2011-01-01

    Background: Self-reported values of height and weight are used increasingly despite warnings that these data - and derived body mass index (BMI) values - might be biased. The present study investigates whether differences between self-reported and measured values are the same for populations from

  8. Evaluation of the Barr & Stroud FP15 and Criterion 400 laser dendrometers for measuring upper stem diameters and heights

    Science.gov (United States)

    Michael S. Williams; Kenneth L. Cormier; Ronald G. Briggs; Donald L. Martinez

    1999-01-01

    Calibrated Barr & Stroud FP15 and Criterion 400 laser dendrometers were tested for reliability in measuring upper stem diameters and heights under typical field conditions. Data were collected in the Black Hills National Forest, which covers parts of South Dakota and Wyoming in the United States. Mixed effects models were employed to account for differences between...

  9. Reported versus measured body weight and height of 4-year-old children and the prevalence of overweight

    NARCIS (Netherlands)

    Scholtens, Salome; Brunekreef, Bert; Visscher, Tommy L. S.; Smit, Henriette A.; Kerkhof, Marjan; de Jongste, Johan C.; Gerritsen, Jorrit; Wijga, Alet H.

    Background: In adults, body weight tends to be underestimated when based on self-reported data. Whether this discrepancy between measured and reported data exists in healthy young children is unclear. We studied whether parental reported body weight and height of 4-year-old children corresponded

  10. Reported versus measured body weight and height of 4-year-old children and the prevalence of overweight

    NARCIS (Netherlands)

    Scholtens, S.; Brunekreef, B.; Visscher, T.L.S.; Smit, H.A.; van de Kerkhof, M.; de Jongste, J.C.; Gerritsen, J.; Wijga, A.H.

    2007-01-01

    Background: In adults, body weight tends to be underestimated when based on self-reported data. Whether this discrepancy between measured and reported data exists in healthy young children is unclear. We studied whether parental reported body weight and height of 4-year-old children corresponded

  11. An improved tree height measurement technique tested on mature southern pines

    Science.gov (United States)

    Don C. Bragg

    2008-01-01

    Virtually all techniques for tree height determination follow one of two principles: similar triangles or the tangent method. Most people apply the latter approach, which uses the tangents of the angles to the top and bottom and a true horizontal distance to the subject tree. However, few adjust this method for ground slope, tree lean, crown shape, and crown...

  12. Measuring Surface Combatant Fleet Effectiveness

    National Research Council Canada - National Science Library

    Crary, Michael

    1999-01-01

    ...? While Measures of Effectiveness for an individual ship can include its number of missiles, speed, and endurance, it is difficult to find a Measure of Effectiveness credible to experienced warplanners...

  13. Measurement errors when estimating the vertical jump height with flight time using photocell devices: the example of Optojump.

    Science.gov (United States)

    Attia, A; Dhahbi, W; Chaouachi, A; Padulo, J; Wong, D P; Chamari, K

    2017-03-01

    Common methods to estimate vertical jump height (VJH) are based on the measurements of flight time (FT) or vertical reaction force. This study aimed to assess the measurement errors when estimating the VJH with flight time using photocell devices in comparison with the gold standard jump height measured by a force plate (FP). The second purpose was to determine the intrinsic reliability of the Optojump photoelectric cells in estimating VJH. For this aim, 20 subjects (age: 22.50±1.24 years) performed maximal vertical jumps in three modalities in randomized order: the squat jump (SJ), counter-movement jump (CMJ), and CMJ with arm swing (CMJarm). Each trial was simultaneously recorded by the FP and Optojump devices. High intra-class correlation coefficients (ICCs) for validity (0.98-0.99) and low limits of agreement (less than 1.4 cm) were found; even a systematic difference in jump height was consistently observed between FT and double integration of force methods (-31% to -27%; p1.2). Intra-session reliability of Optojump was excellent, with ICCs ranging from 0.98 to 0.99, low coefficients of variation (3.98%), and low standard errors of measurement (0.8 cm). It was concluded that there was a high correlation between the two methods to estimate the vertical jump height, but the FT method cannot replace the gold standard, due to the large systematic bias. According to our results, the equations of each of the three jump modalities were presented in order to obtain a better estimation of the jump height.

  14. Effect of roughness lengths on surface energy and the planetary boundary layer height over high-altitude Ngoring Lake

    Science.gov (United States)

    Li, Zhaoguo; Lyu, Shihua; Wen, Lijuan; Zhao, Lin; Meng, Xianhong; Ao, Yinhuan

    2017-08-01

    The special climate environment creates a distinctive air-lake interaction characteristic in the Tibetan Plateau (TP) lakes, where the variations of surface roughness lengths also differ somewhat from those of other regions. However, how different categories of roughness lengths affect the lake surface energy exchange and the planetary boundary layer height (PBLH) remains unclear in the TP lakes. In this study, we used a tuned Weather Research and Forecasting (WRF) model version 3.6.1 to investigate the responses of the freeze-up date, turbulent fluxes, meteorological variables, and PBLH to surface roughness length variations in Ngoring Lake. Of all meteorological variables, the lake surface temperature responded to roughness length variations most sensitively; increasing roughness lengths can put the lake freeze-up date forward. The effect of momentum roughness length on wind speed was significantly affected by the fetch length. The increase in the roughness length for heat can induce the increment of the nightly PBLH in most months, especially for the central lake area in autumn. The primary factors that contribute to sensible heat flux (H) and latent heat flux (LE) were the roughness lengths for heat and momentum during the ice-free period, respectively. Increasing roughness length for heat can increase the nightly PBLH, and decreasing roughness length for moisture can also promote growth of the PBLH, but there was no obvious correlation between the momentum roughness length and the PBLH.

  15. Summations over equilaterally triangulated surfaces and the critical string measure

    Science.gov (United States)

    Smit, Dirk-Jan

    1992-01-01

    We propose a new approach to the summation over dynamically triangulated Riemann surfaces which does not rely on properties of the potential in a matrix model. Instead, we formulate a purely algebraic discretization of critical string path integral. This is combined with a technique which assigns to each equilateral triangulation of a two-dimensional surface a Riemann surface defined over a certain finite extension of the field of rational numbers, i.e. an arthmetic surface. Thus we establish a new formulation in which the sum over randomly triangulated surfaces defines an invariant measure on the moduli space of arithmetic surfaces. It is shown that because of this it is far from obvious that this measure for large genera approximates the measure defined by the continuum theory, i.e. Liouville theory or critical string theory. In low genus this subtlety does not exist. In the case of critical string theory we explicity compute the volume of the moduli space of arithmetic surfaces in terms of the modular height function and show that for low genus it approximates correctly the continuum measure. We also discuss a continuum limit which bears some resemblance with a double scaling limit in matrix models.

  16. Summations over equilaterally triangulated surfaces and the critical string measure

    International Nuclear Information System (INIS)

    Smit, D.J.; Lawrence Berkeley Lab., CA

    1992-01-01

    We propose a new approach to the summation over dynamically triangulated Riemann surfaces which does not rely on properties of the potential in a matrix model. Instead, we formulate a purely algebraic discretization of critical string path integral. This is combined with a technique which assigns to each equilateral triangulation of a two-dimensional surface a Riemann surface defined over a certain finite extension of the field of rational numbers, i.e. an arithmetic surface. Thus we establish a new formulated in which the sum over randomly triangulated surfaces defines an invariant measure on the moduli space of arithmetic surfaces. It is shown that because of this it is far from obvious that this measure for large genera approximates the measure defined by the continuum theory, i.e. Liouville theory or critical string theory. In low genus this subtlety does not exist. In the case of critical string theory we explicitly compute the volume of the moduli space of arithmetic surfaces in terms of the modular height function and show that for low genus it approximates correctly the continuum measure. We also discuss a continuum limit which bears some resemblance with a double scaling limit in matrix models. (orig.)

  17. The validity of self-reported vs. measured body weight and height and the effect of self-perception.

    Science.gov (United States)

    Gokler, Mehmet Enes; Bugrul, Necati; Sarı, Ahu Ozturk; Metintas, Selma

    2018-01-01

    The objective was to assess the validity of self-reported body weight and height and the possible influence of self-perception of body mass index (BMI) status on the actual BMI during the adolescent period. This cross sectional study was conducted on 3918 high school students. Accurate BMI perception occurred when the student's self-perception of their BMI status did not differ from their actual BMI based on measured height and weight. Agreement between the measured and self-reported body height and weight and BMI values was determined using the Bland-Altman metod. To determine the effects of "a good level of agreement", hierarchical logistic regression models were used. Among male students who reported their BMI in the normal region, 2.8% were measured as overweight while 0.6% of them were measured as obese. For females in the same group, these percentages were 1.3% and 0.4% respectively. Among male students who perceived their BMI in the normal region, 8.5% were measured as overweight while 0.4% of them were measured as obese. For females these percentages were 25.6% and 1.8% respectively. According to logistic regression analysis, residence and accurate BMI perception were significantly associated with "good agreement" ( p ≤ 0.001). The results of this study demonstrated that in determining obesity and overweight statuses, non-accurate weight perception is a potential risk for students.

  18. Improved boundary layer height measurement using a fuzzy logic method: Diurnal and seasonal variabilities of the convective boundary layer over a tropical station

    Science.gov (United States)

    Allabakash, S.; Yasodha, P.; Bianco, L.; Venkatramana Reddy, S.; Srinivasulu, P.; Lim, S.

    2017-09-01

    This paper presents the efficacy of a "tuned" fuzzy logic method at determining the height of the boundary layer using the measurements from a 1280 MHz lower atmospheric radar wind profiler located in Gadanki (13.5°N, 79°E, 375 mean sea level), India, and discusses the diurnal and seasonal variations of the measured convective boundary layer over this tropical station. The original fuzzy logic (FL) method estimates the height of the atmospheric boundary layer combining the information from the range-corrected signal-to-noise ratio, the Doppler spectral width of the vertical velocity, and the vertical velocity itself, measured by the radar, through a series of thresholds and rules, which did not prove to be optimal for our radar system and geographical location. For this reason the algorithm was tuned to perform better on our data set. Atmospheric boundary layer heights obtained by this tuned FL method, the original FL method, and by a "standard method" (that only uses the information from the range-corrected signal-to-noise ratio) are compared with those obtained from potential temperature profiles measured by collocated Global Positioning System Radio Sonde during years 2011 and 2013. The comparison shows that the tuned FL method is more accurate than the other methods. Maximum convective boundary layer heights are observed between 14:00 and 15:00 local time (LT = UTC + 5:30) for clear-sky days. These daily maxima are found to be lower during winter and postmonsoon seasons and higher during premonsoon and monsoon seasons, due to net surface radiation and convective processes over this region being more intense during premonsoon and monsoon seasons and less intense in winter and postmonsoon seasons.

  19. Impact of Assimilating Surface Velocity Observations on the Model Sea Surface Height Using the NCOM-4DVAR

    Science.gov (United States)

    2016-09-26

    surface velocity observations available in 15-min intervals for each drifter. The observations are given an error standard deviation value of 0.02m s21... Standard Form 298 (Rev. 8/98) REPORT DOCUMENTATION PAGE Prescribed by ANSI Std. Z39.18 Form Approved OMB No. 0704-0188 The public reporting... statistical analysis is done by not only examining the SSH forecast error across the entire do- main, but also by concentrating on the areamost densely covered

  20. Applications of MODIS Fluorescent Line Height Measurements to Monitor Water Quality Trends and Algal Bloom Activity

    Science.gov (United States)

    Fischer, Andrew; Moreno-Mardinan, Max; Ryan, John P.

    2012-01-01

    Recent advances in satellite and airborne remote sensing, such as improvements in sensor and algorithm calibrations, processing techniques and atmospheric correction procedures have provided for increased coverage of remote-sensing, ocean-color products for coastal regions. In particular, for the Moderate Resolution Imaging Spectrometer (MODIS) sensor calibration updates, improved aerosol retrievals and new aerosol models has led to improved atmospheric correction algorithms for turbid waters and have improved the retrieval of ocean color in coastal waters. This has opened the way for studying ocean phenomena and processes at finer spatial scales, such as the interactions at the land-sea interface, trends in coastal water quality and algal blooms. Human population growth and changes in coastal management practices have brought about significant changes in the concentrations of organic and inorganic, particulate and dissolved substances entering the coastal ocean. There is increasing concern that these inputs have led to declines in water quality and have increase local concentrations of phytoplankton, which cause harmful algal blooms. In two case studies we present MODIS observations of fluorescence line height (FLH) to 1) assess trends in water quality for Tampa Bay, Florida and 2) illustrate seasonal and annual variability of algal bloom activity in Monterey Bay, California as well as document estuarine/riverine plume induced red tide events. In a comprehensive analysis of long term (2003-2011) in situ monitoring data and satellite imagery from Tampa Bay we assess the validity of the MODIS FLH product against chlorophyll-a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions and to develop a near decadal trend in

  1. Simulating an Autonomously Operating Low-Cost Static Terrestrial LiDAR for Multitemporal Maize Crop Height Measurements

    Directory of Open Access Journals (Sweden)

    Sophie Crommelinck

    2016-03-01

    Full Text Available In order to optimize agricultural processes, near real-time spatial information about in-field variations, such as crop height development (i.e., changes over time, is indispensable. This development can be captured with a LiDAR system. However, its applicability in precision agriculture is often hindered due to high costs and unstandardized processing methods. This study investigates the potential of an autonomously operating low-cost static terrestrial laser scanner (TLS for multitemporal height monitoring of maize crops. A low-cost system is simulated by artificially reducing the point density of data captured during eight different campaigns. The data were used to derive and assess crop height models (CHM. Results show that heights calculated with CHM based on the unreduced point cloud are accurate when compared to manually measured heights (mean deviation = 0.02 m, standard deviation = 0.15 m, root mean square error (RMSE = 0.16 m. When reducing the point cloud to 2% of its original size to simulate a low-cost system, this difference increases (mean deviation = 0.12 m, standard deviation = 0.19 m, RMSE = 0.22 m. We found that applying the simulated low-cost TLS system in precision agriculture is possible with acceptable accuracy up to an angular scan resolution of 8 mrad (i.e., point spacing of 80 mm at 10 m distance. General guidelines for the measurement set-up and an automatically executable method for CHM generation and assessment are provided and deserve consideration in further studies.

  2. Accuracy of vertical height measurements on direct digital panoramic radiographs using posterior mandibular implants and metal balls as reference objects

    Science.gov (United States)

    Vazquez, L; Nizamaldin, Y; Combescure, C; Nedir, R; Bischof, M; Dohan Ehrenfest, DM; Carrel, J-P; Belser, UC

    2013-01-01

    Objectives: Conventional panoramic radiography, a widely used radiographic examination tool in implant treatment planning, allows evaluation of the available bone height before inserting posterior mandibular implants. Image distortion and vertical magnification due to projection geometry is well described for rotational panoramic radiographs. To assess the accuracy of vertical height measurements on direct digital panoramic radiographs, implants and metal balls positioned in the posterior mandible were used as radio-opaque reference objects. The reproducibility of the measuring method was assessed by the inter- and intraobserver agreements. Methods: Direct digital panoramic radiographs, performed using a Kodak 8000C (Eastman Kodak Company, Rochester, NY), of 17 partially edentulous patients (10 females, 7 males, mean age 65 years) were selected from an X-ray database gathered during routine clinical evaluation of implant sites. Proprietary software and a mouse-driven calliper were used to measure the radiological length of 25 implants and 18 metal reference balls, positioned in mandibular posterior segments. The distortion ratio (DR) was calculated by dividing the radiological implant length by the implant's real length and the radiological ball height by the ball's real height. Results: Mean vertical DR was 0.99 for implants and 0.97 for balls, and was unrelated to mandibular sites, side, age, gender or observer. Inter- and intraobserver agreements were acceptable for both reference objects. Conclusions: Vertical measurements had acceptable accuracy and reproducibility when a software-based calibrated measurement tool was used, confirming that digital panoramic radiography can be reliably utilized to determine the pre-operative implant length in premolar and molar mandibular segments. PMID:23360688

  3. Surface charge measurement by the Pockels effect

    CERN Document Server

    Sam, Y L

    2001-01-01

    have been observed by applying both impulse and AC voltages to a needle electrode in direct contact with the BSO. AC surface discharge behaviour of polymeric materials bonded to the BSO has also been investigated. The effect of the surrounding environment has been experimentally examined by placing the cell inside a vacuum chamber. Surface charge measurements have been made at various atmospheric pressures. The effect of an electro-negative gas (Sulphur Hexafluoride) on the surface charge distribution has also been investigated. This thesis is concerned with the design and development of a surface charge measurement system using Pockels effect. The measurement of surface charge is important in determining the electrical performance of high voltage insulation materials. The method proposed allows on-line measurement of charge and can generate two-dimensional images that represent the charge behaviour on the surface of the material under test. The measurement system is optical and uses a Pockels crystal as the ...

  4. Effective aerodynamic roughness estimated from airborne laser altimeter measurements of surface features

    NARCIS (Netherlands)

    De Vries, AC; Kustas, WP; Ritchie, JC; Klaassen, W; Menenti, M; Rango, A; Prueger, JH

    2003-01-01

    Aerodynamic roughness length (z(0)) and displacement height (d(0)) are important surface parameters for estimating surface fluxes in numerical models. These parameters are generally determined from wind flow characteristics using logarithmic wind profiles measured at a meteorological tower or by

  5. On the measurement of the surface energy budget over a land ...

    Indian Academy of Sciences (India)

    e-mail: bhat@caos.iisc.ernet.in. The measurement of surface energy balance over a land surface in an open area in Bangalore is .... Sensors used in the present experimental setup and their specifications. These instruments were procured .... the value of the scalar at the roughness height zos. ψm and ψs are the M–O ...

  6. The performance of modified blood pressure-to-height ratio as a screening measure for identifying children with hypertension.

    Science.gov (United States)

    Ma, Chunming; Lu, Qiang; Yin, Fuzai

    2016-01-01

    This study evaluated the accuracy of modified blood pressure-to-height ratio (MBPHR) for identifying hypertension in Han children aged 7-12 years. In 2011, anthropometric measurements were assessed in a cross-sectional population-based study of 1352 Han children aged 7-12 years. Elevated blood pressure was defined according to the 2004 National High Blood Pressure Education Program Working Group definition (as gold standard). The following equations for MBPHR were used: modified systolic blood pressure to height ratio(MSBPHR) = SBP(mmHg)/(height(cm) + 7 × (13 - age(years))), modified diastolic blood pressure to height ratio (MDBPHR) = DBP(mmHg)/(height(cm) + 7 × (13 - age(years))). Receiver operating characteristic curve analyses were performed to assess the accuracy of MSBPHR and MDBPHR as diagnostic tests for elevated SBP and DBP, respectively. The accuracy of MSBPHR and MDBPHR (assessed by area under the curve) for identifying elevated SBP and DBP were over 0.85 (0.953-1.000). When elevated blood pressure was defined by MBPHR (age-dependent cut-off point), the sensitivities were 99.1% in boys and 97.0% in girls and the specificities were 89.0% in boys and 92.3% in girls. When elevated blood pressure was defined by MBPHR (non-age-dependent cut-off point), the sensitivities were 96.4% in boys and 99.2% in girls and the specificities were 81.2% in boys and 75.5% in girls. MBPHR is an accurate index for screening hypertension in children, but is not superior to BPHR. Compared with age-dependent BPHR cutoff points, non-age-dependent MBPHR cut-off point is simple but increase the proportion of reexamination.

  7. Contact area measurements on structured surfaces

    DEFF Research Database (Denmark)

    Kücükyildiz, Ömer Can; Jensen, Sebastian Hoppe Nesgaard; De Chiffre, Leonardo

    In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means.......In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means....

  8. Microthermal Instrument for Measuring Surface Layer Seeing

    Science.gov (United States)

    Li, Xue-Bao; Zheng, Yan-Fang; Deng, Lin Hua; Xu, Guang

    2012-02-01

    Microthermal fluctuations are introduced by atmospheric turbulence very near the ground. In order to detect microthermal fluctuations at Fuxian Solar Observatory (FSO), a microthermal instrument has been developed. The microthermal instrument consists of a microthermal sensor, which is based on a Wheatstone bridge circuit and uses fine tungsten filaments as resistance temperature detectors, an associated signal processing unit, and a data collection, & communication subsystem. In this paper, after a brief introduction to surface layer seeing, we discuss the instrumentation behind the microthermal detector we have developed and then present the results obtained. The results of the evaluation indicate that the effect of the turbulent surface boundary layer to astronomical seeing would become sufficiently small when installing a telescope at a height of 16m or higher from the ground at FSO.

  9. Fit-To-Fight: Waist vs Waist/Height Measurements to Determine an Individual's Fitness Level - A Study in Statistical Regression and Analysis

    National Research Council Canada - National Science Library

    Swiderski, Steven J

    2005-01-01

    .... The abdominal measurement is a "one-size-fits-all" fitness standard. This research determines that a person's waist-to-height ratio is a better measurement than the waist measurement to estimate an individual's fitness level...

  10. Self-reported versus measured body height and weight in Polish adult men: the risk of underestimating obesity rates.

    Science.gov (United States)

    Łopuszańska, Monika; Lipowicz, Anna; Kołodziej, Halina; Szklarska, Alicja; Bielicki, Tadeusz

    2015-01-01

    In some epidemiological studies, self-reported height and weight are often used to save time and money. Self-reported height and weight are commonly used to assess the prevalence of obesity. The aim of this study was to assess the differences between self-reported and measured height and weight in adult men, and to determine how the accuracy of self-reported data depended on age and education. The prevalence of obesity was also calculated based both on self-reported and measured data. Data were collected during two population studies carried out in Wroclaw in 2010. One study included 1,194 19-year-old males who reported for the health examination mandated by the National Conscription Board (younger group). The other group included 355 men between 35 and 80 years old who reported for a ten-year follow-up (older group). Data were analyzed separately for both age groups. Both younger and older subjects overestimated their height by 1.4 cm and 1.0 cm (1.4 cm, 95 % CI: 1.26, 1.51, and 1.0 cm, 95 % CI: 0.85, 1.26, respectively). On average, younger subjects overestimated their weight by 0.7 kilograms (95 % CI: 0.55, 0.92), whereas older subjects underestimated their weight by 0.9 kilograms (95 % CI: -1.15, -0.48). The lower the level of education, the more the subjects overestimated their height. Adult men systematically overestimate their height and underestimate their weight. The magnitude of the inaccuracy depends on level of education. When self-reported data are used, the prevalence of obesity is generally underestimated. Using self-reported data to calculate BMI can lead to a substantial underestimation of the proportion of underweight and obese individuals in a population. Finally, using self-reported values for height in studies on social inequality may lead to false conclusions. Background: In some epidemiological studies, self-reported height and weight are often used to save time and money. Self-reported height and weight are commonly used to assess the

  11. Trends in significant wave height and surface wind speed in the China Seas between 1988 and 2011

    Science.gov (United States)

    Zheng, Chongwei; Zhang, Ren; Shi, Weilai; Li, Xin; Chen, Xuan

    2017-10-01

    Wind and waves are key components of the climate system as they drive air-sea interactions and influence weather systems and atmospheric circulation. In marine environments, understanding surface wind and wave fields and their evolution over time is important for conducting safe and efficient human activities, such as navigation and engineering. This study considers long-term trends in the sea surface wind speed (WS) and significant wave height (SWH) in the China Seas over the period 1988-2011 using the Cross-Calibrated Multi-Platform (CCMP) ocean surface wind product and a 24-year hindcast wave dataset obtained from the WAVEWATCH-III (WW3) wave model forced with CCMP winds. The long-term trends in WS and SWH in the China Seas are analyzed over the past 24 years to provide a reference point from which to assess future climate change and offshore wind and wave energy resource development in the region. Results demonstrate that over the period 1988-2011 in the China Seas: 1) WS and SWH showed a significant increasing trend of 3.38 cm s-1 yr-1 and 1.52 cm yr-1, respectively; 2) there were notable regional differences in the long-term trends of WS and SWH; 3) areas with strong increasing trends were located mainly in the middle of the Tsushima Strait, the northern and southern areas of the Taiwan Strait, and in nearshore regions of the northern South China Sea; and 4) the long-term trend in WS was closely associated with El Niño and a significant increase in the occurrence of gale force winds in the region.

  12. Surface texture measurement for dental wear applications

    Science.gov (United States)

    Austin, R. S.; Mullen, F.; Bartlett, D. W.

    2015-06-01

    The application of surface topography measurement and characterization within dental materials science is highly active and rapidly developing, in line with many modern industries. Surface measurement and structuring is used extensively within oral and dental science to optimize the optical, tribological and biological performance of natural and biomimetic dental materials. Although there has historically been little standardization in the use and reporting of surface metrology instrumentation and software, the dental industry is beginning to adopt modern areal measurement and characterization techniques, especially as the dental industry is increasingly adopting digital impressioning techniques in order to leverage CAD/CAM technologies for the design and construction of dental restorations. As dental treatment becomes increasingly digitized and reliant on advanced technologies such as dental implants, wider adoption of standardized surface topography and characterization techniques will become evermore essential. The dental research community welcomes the advances that are being made in surface topography measurement science towards realizing this ultimate goal.

  13. The use of LIDAR Technology for Measuring Mixing Heights under the Photochemical Assessment Monitoring Program; leveraging research under the joint DISCOVER-AQ/FRAPPÉ Missions

    Science.gov (United States)

    The operational use of ceilometers across the United States has been limited to detection of cloud-base heights across the Automatic Surface Observing Systems (ASOS) primarily operated by the National Weather Service and the Federal Aviation Administration. Continued improvements...

  14. Single camera multi-view anthropometric measurement of human height and mid-upper arm circumference using linear regression.

    Science.gov (United States)

    Liu, Yingying; Sowmya, Arcot; Khamis, Heba

    2018-01-01

    Manually measured anthropometric quantities are used in many applications including human malnutrition assessment. Training is required to collect anthropometric measurements manually, which is not ideal in resource-constrained environments. Photogrammetric methods have been gaining attention in recent years, due to the availability and affordability of digital cameras. The primary goal is to demonstrate that height and mid-upper arm circumference (MUAC)-indicators of malnutrition-can be accurately estimated by applying linear regression to distance measurements from photographs of participants taken from five views, and determine the optimal view combinations. A secondary goal is to observe the effect on estimate error of two approaches which reduce complexity of the setup, computational requirements and the expertise required of the observer. Thirty-one participants (11 female, 20 male; 18-37 years) were photographed from five views. Distances were computed using both camera calibration and reference object techniques from manually annotated photos. To estimate height, linear regression was applied to the distances between the top of the participants head and the floor, as well as the height of a bounding box enclosing the participant's silhouette which eliminates the need to identify the floor. To estimate MUAC, linear regression was applied to the mid-upper arm width. Estimates were computed for all view combinations and performance was compared to other photogrammetric methods from the literature-linear distance method for height, and shape models for MUAC. The mean absolute difference (MAD) between the linear regression estimates and manual measurements were smaller compared to other methods. For the optimal view combinations (smallest MAD), the technical error of measurement and coefficient of reliability also indicate the linear regression methods are more reliable. The optimal view combination was the front and side views. When estimating height by linear

  15. Technique for measuring very high surface velocities

    International Nuclear Information System (INIS)

    Maron, Y.

    1977-01-01

    An interferometric technique for measuring displacements of surfaces moving at velocities in the range of a few millimeters per microsecond is presented. The Doppler shift of frequency of light scattered from such surfaces is too high to be detectable by known devices. The present technique is based upon monitoring the signal resulting from the interference between two beams reflected from the surface at different incidence angles. Measurement systems for specularly as well as diffusely reflecting surfaces are described. Light source with very modest temporal coherence delivering about 100 mw power is required. The accuracy of the technique is discussed. (author)

  16. Surface texture measurement for additive manufacturing

    International Nuclear Information System (INIS)

    Triantaphyllou, Andrew; Tomita, Ben; Milne, Katherine A; Giusca, Claudiu L; Macaulay, Gavin D; Roerig, Felix; Hoebel, Matthias; Leach, Richard K

    2015-01-01

    The surface texture of additively manufactured metallic surfaces made by powder bed methods is affected by a number of factors, including the powder’s particle size distribution, the effect of the heat source, the thickness of the printed layers, the angle of the surface relative to the horizontal build bed and the effect of any post processing/finishing. The aim of the research reported here is to understand the way these surfaces should be measured in order to characterise them. In published research to date, the surface texture is generally reported as an Ra value, measured across the lay. The appropriateness of this method for such surfaces is investigated here. A preliminary investigation was carried out on two additive manufacturing processes—selective laser melting (SLM) and electron beam melting (EBM)—focusing on the effect of build angle and post processing. The surfaces were measured using both tactile and optical methods and a range of profile and areal parameters were reported. Test coupons were manufactured at four angles relative to the horizontal plane of the powder bed using both SLM and EBM. The effect of lay—caused by the layered nature of the manufacturing process—was investigated, as was the required sample area for optical measurements. The surfaces were also measured before and after grit blasting. (paper)

  17. Constructing invariant fairness measures for surfaces

    DEFF Research Database (Denmark)

    Gravesen, Jens; Ungstrup, Michael

    2002-01-01

    The paper proposes a rational method to derive fairness measures for surfaces. It works in cases where isophotes, reflection lines, planar intersection curves, or other curves are used to judge the fairness of the surface. The surface fairness measure is derived by demanding that all the given cu...... of curves. Six basic third order invariants by which the fairing measures can be expressed are defined. Furthermore, the geometry of a plane intersection curve is studied, and the variation of the total, the normal, and the geodesic curvature and the geodesic torsion is determined....

  18. Longitudinal changes in transtibial amputee gait characteristics when negotiating a change in surface height during continuous gait.

    Science.gov (United States)

    Barnett, C T; Polman, R C J; Vanicek, N

    2014-08-01

    Negotiating a raised surface during continuous gait is an important activity of daily living and is a potentially hazardous task with regards to trips, falls and fall-related injury. However, it is not known how recent transtibial amputees adapt to performing stepping gait tasks in the 6-month period following discharge from rehabilitation. Recent transtibial amputees performed continuous gait trials, stepping onto and from a raised surface walkway representing the height of a street kerb, whilst kinematic and kinetic data were recorded at one, three and six months post-discharge from rehabilitation. Walking speed increased when stepping down (p=0.04) and was invariant across the study period when stepping up. At one month post-discharge, participants displayed an affected lead limb preference (90.8%) when stepping down and an intact lead limb preference (70.0%) when stepping up, although these lead limb preferences diminished over time. Participants spent more time in stance on the intact limb compared to the affected limb in both stepping down (trail limb) (p=0.01) and stepping up (lead and trail limbs) (p=0.05). Participants displayed significantly greater joint mobility and power bursts in the intact trail limb when stepping down and in the intact lead limb when stepping up. Transtibial amputees prefer to exploit intact limb function to a greater extent, although over time, the means by which this occurs changes which affects the initial lead limb preferences. The results from the current study enable future evidence-based therapeutic and prosthetic interventions to be designed that improve transtibial amputee stepping gait. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Surface tension measurements with a smartphone

    Science.gov (United States)

    Goy, Nicolas-Alexandre; Denis, Zakari; Lavaud, Maxime; Grolleau, Adrian; Dufour, Nicolas; Deblais, Antoine; Delabre, Ulysse

    2017-11-01

    Smartphones are increasingly used in higher education and at university in mechanics, acoustics, and even thermodynamics as they offer a unique way to do simple science experiments. In this article, we show how smartphones can be used in fluid mechanics to measure surface tension of various liquids, which could help students understand the concept of surface tension through simple experiments.

  20. Constructing Invariant Fairness Measures for Surfaces

    DEFF Research Database (Denmark)

    Gravesen, Jens; Ungstrup, Michael

    1998-01-01

    This paper presents a general method which from an invariant curve fairness measure constructs an invariant surface fairness measure. Besides the curve fairness measure one only needs a class of curves on the surface for which one wants to apply the curve measure. The surface measure at a point...... variation.The method is extended to the case where one considers, not the fairness of one curve, but the fairness of a one parameter family of curves. Such a family is generated by the flow of a vector field, orthogonal to the curves. The first, respectively the second order derivative along the curve...... of the size of this vector field is used as the fairness measure on the family.Six basic 3rd order invariants satisfying two quadratic equations are defined. They form a complete set in the sense that any invariant 3rd order function can be written as a function of the six basic invariants together...

  1. Mixing height over water and its role on the correlation between temperature and humidity fluctuations in the unstable surface layer

    DEFF Research Database (Denmark)

    Sempreviva, A.M.; Gryning, Sven-Erik

    2000-01-01

    Results from an experimental investigation of the mixing height over inner Danish waters carried out from September 1990 to October 1992, are discussed. The statistical analysis of the mixed-layer height (z(i)) over the sea does not exhibit the daily variation that is characteristic of the mixed ...

  2. Preparation of stable silica surfaces for surface forces measurement

    Science.gov (United States)

    Ren, Huai-Yin; Mizukami, Masashi; Kurihara, Kazue

    2017-09-01

    A surface forces apparatus (SFA) measures the forces between two surfaces as a function of the surface separation distance. It is regarded as an essential tool for studying the interactions between two surfaces. However, sample surfaces used for the conventional SFA measurements have been mostly limited to thin (ca. 2-3 μm) micas, which are coated with silver layers (ca. 50 nm) on their back, due to the requirement of the distance determination by transmission mode optical interferometry called FECO (fringes of equal chromatic order). The FECO method has the advantage of determining the absolute distance, so it should be important to increase the availability of samples other than mica, which is chemically nonreactive and also requires significant efforts for cleaving. Recently, silica sheets have been occasionally used in place of mica, which increases the possibility of surface modification. However, in this case, the silver layer side of the sheet is glued on a cylindrical quartz disc using epoxy resin, which is not stable in organic solvents and can be easily swollen or dissolved. The preparation of substrates more stable under severe conditions, such as in organic solvents, is necessary for extending application of the measurement. In this study, we report an easy method for preparing stable silica layers of ca. 2 μm in thickness deposited on gold layers (41 nm)/silica discs by sputtering, then annealed to enhance the stability. The obtained silica layers were stable and showed no swelling in organic solvents such as ethanol and toluene.

  3. Profile correction to electron temperature and enhancement factor in soft-x-ray pulse-height-analysis measurements in tokamaks

    International Nuclear Information System (INIS)

    Sesnic, S.; Diesso, M.; Hill, K.; Holland, A.; Pohl, F.

    1988-01-01

    Because soft-x-ray pulse-height-analysis spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. The correction factors for the electron temperature and the enhancement factor as a function of the temperature and density profile parameters and the energy are obtained. The spectrum distortion due to pulse pileup effects is also evaluated. A set of curves is given from which the distortion of the spectrum can be obtained if the electron temperature, the Be filter thickness, and the electronic parameters of the acquisition system are known. PG 1810,1812 ID 131801CON N X-ray diagnostics TT Profile correction to electron temperature and enhancement factor in soft-x-ray pulse-height-analysis measurements in tokamaks AU S. Sesnic, M. Diesso, K. Hill, and A. Holland LO Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 AU F. Pohl LO Max-Planck Institut fuer Plasmaphysik, 8046-Garching, Federal Republic of Germany SD (Presented on 16 March 1988) AB Because soft-x-ray pulse-height-analysis spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. The correction factors for the electron temperature and the enhancement factor as a function of the temperature and density profile parameters and the energy are obtained. The spectrum distortion due to pulse pileup effects is also evaluated. A set of curves is given from which the distortion of the spectrum can be obtained if the electron tempe

  4. Comparison of Evaporation Duct Height Measurement Methods and Their Impact on Radar Propagation Estimates

    National Research Council Canada - National Science Library

    Whalen, John

    1998-01-01

    A study was performed to compare shipboard measurements of atmospheric parameters that impact the evaporation duct and its effect on the propagation of electromagnetic energy from the AEGIS AN/SPY-1 radars...

  5. Variations of the Wake Height over the Bolund Escarpment Measured by a Scanning Lidar

    DEFF Research Database (Denmark)

    Lange, Julia; Mann, Jakob; Angelou, Nikolas

    2016-01-01

    The wake zone behind the escarpment of the Bolund peninsula in the Roskilde Fjord, Denmark, has been investigated with the help of a continuous-wave Doppler lidar. The instrument measures the line-of-sight wind speed 390 times per second in highly resolved 7- m tall profiles by rapidly changing t...

  6. Diagnostic accuracy of fundal height and handheld ultrasound-measured abdominal circumference to screen for fetal growth abnormalities

    Science.gov (United States)

    Haragan, Adriane F.; Hulsey, Thomas C.; Hawk, Angela F.; Newman, Roger B.; Chang, Eugene Y.

    2015-01-01

    OBJECTIVE We sought to compare fundal height and handheld ultrasound–measured fetal abdominal circumference (HHAC) for the prediction of fetal growth restriction (FGR) or large for gestational age. STUDY DESIGN This was a diagnostic accuracy study in nonanomalous singleton pregnancies between 24 and 40 weeks’ gestation. Patients underwent HHAC and fundal height measurement prior to formal growth ultrasound. FGR was defined as estimated fetal weight less than 10%, whereas large for gestational age was defined as estimated fetal weight greater than 90%. Sensitivity and specificity were calculated and compared using methods described elsewhere. RESULTS There were 251 patients included in this study. HHAC had superior sensitivity and specificity for the detection of FGR (sensitivity, 100% vs 42.86%) and (specificity, 92.62% vs 85.24%). HHAC had higher specificity but lower sensitivity when screening for LGA (specificity, 85.66% vs 66.39%) and (sensitivity, 57.14% vs 71.43%). CONCLUSION HHAC could prove to be a valuable screening tool in the detection of FGR. Further studies are needed in a larger population. PMID:25818672

  7. LASSI - A Scanning Differential Ac Interferometer For Surface Profile And Roughness Measurement

    Science.gov (United States)

    Makosch, Guenter

    1989-03-01

    LASSI (Laser Spot Scanning Interferometer) is a highly precise and versatile surface profilometer developed for various measurement applications in surface lapping, etching and polishing processes. The principle of measurement is based on a differential interferometer in which two parallel light beams split from a He-Ne laser are scanned across a sample surface. The phase difference of the reflected beams changes proportionally with the height variation between the two spots illuminated on the surface. In using a phase-locked method to determine the phase differences height variations of a surface can be measured with manometer precision. The range of applications of an instrument built on this principle encompasses step height, roughness, slope, and profile measurement of surface microtopographies. Special versions of this tool have also been developed for in situ monitoring of etch or deposition rates in sputter-etching and wet etching processes. In this paper, the principle of measurement will be described and some theoretical aspects of the measurement technique will be discussed. The various LASSI tools and their applications are reviewed.

  8. Measurement of Gas-Surface Accommodation

    Science.gov (United States)

    Trott, W. M.; Rader, D. J.; Castañeda, J. N.; Torczynski, J. R.; Gallis, M. A.

    2008-12-01

    Thermal accommodation coefficients have been determined for a variety of gas-surface combinations using an experimental apparatus developed to measure both the pressure dependence of the conductive heat flux and the variation of gas density between parallel plates separated by a gas-filled gap. Effects of gas composition, surface roughness and surface contamination have been examined with this system, and the behavior of gas mixtures has also been explored. Results are discussed in comparison with previous parallel-plate experimental studies as well as numerical simulations.

  9. The role of probe oxide in local surface conductivity measurements

    Science.gov (United States)

    Barnett, C. J.; Kryvchenkova, O.; Wilson, L. S. J.; Maffeis, T. G. G.; Kalna, K.; Cobley, R. J.

    2015-05-01

    Local probe methods can be used to measure nanoscale surface conductivity, but some techniques including nanoscale four point probe rely on at least two of the probes forming the same low resistivity non-rectifying contact to the sample. Here, the role of probe shank oxide has been examined by carrying out contact and non-contact I V measurements on GaAs when the probe oxide has been controllably reduced, both experimentally and in simulation. In contact, the barrier height is pinned but the barrier shape changes with probe shank oxide dimensions. In non-contact measurements, the oxide modifies the electrostatic interaction inducing a quantum dot that alters the tunneling behavior. For both, the contact resistance change is dependent on polarity, which violates the assumption required for four point probe to remove probe contact resistance from the measured conductivity. This has implications for all nanoscale surface probe measurements and macroscopic four point probe, both in air and vacuum, where the role of probe oxide contamination is not well understood.

  10. Metal-organic semiconductor interfacial barrier height determination from internal photoemission signal in spectral response measurements

    Science.gov (United States)

    Kumar, Sandeep; Iyer, S. Sundar Kumar

    2017-04-01

    Accurate and convenient evaluation methods of the interfacial barrier ϕb for charge carriers in metal semiconductor (MS) junctions are important for designing and building better opto-electronic devices. This becomes more critical for organic semiconductor devices where a plethora of molecules are in use and standardised models applicable to myriads of material combinations for the different devices may have limited applicability. In this paper, internal photoemission (IPE) from spectral response (SR) in the ultra-violet to near infra-red range of different MS junctions of metal-organic semiconductor-metal (MSM) test structures is used to determine more realistic MS ϕb values. The representative organic semiconductor considered is [6, 6]-phenyl C61 butyric acid methyl ester, and the metals considered are Al and Au. The IPE signals in the SR measurement of the MSM device are identified and separated before it is analysed to estimate ϕb for the MS junction. The analysis of IPE signals under different bias conditions allows the evaluation of ϕb for both the front and back junctions, as well as for symmetric MSM devices.

  11. Interpreting the probe-surface interaction of surface measuring instruments, or what is a surface?

    Science.gov (United States)

    Leach, Richard; Weckenmann, Albert; Coupland, Jeremy; Hartmann, Wito

    2014-09-01

    When using dimensional measuring instruments it is assumed that there is a property of the object, which we call surface, that is present before during and after the measurement, i.e. the surface is a fundamental property of an object that can, by appropriate means, be used to measure geometry. This paper will attempt to show that the fundamental property ‘surface’ does not exist in any simple form and that all the information we can have about a surface is the measurement data, which will include measurement uncertainty. Measurement data, or what will be referred to as the measured surface, is all that really exists. In this paper the basic physical differences between mechanically, electromagnetically and electrically measured surfaces are highlighted and discussed and accompanied by measurement results on a roughness artefact.

  12. Interpreting the probe-surface interaction of surface measuring instruments, or what is a surface?

    International Nuclear Information System (INIS)

    Leach, Richard; Weckenmann, Albert; Hartmann, Wito; Coupland, Jeremy

    2014-01-01

    When using dimensional measuring instruments it is assumed that there is a property of the object, which we call surface, that is present before during and after the measurement, i.e. the surface is a fundamental property of an object that can, by appropriate means, be used to measure geometry. This paper will attempt to show that the fundamental property ‘surface’ does not exist in any simple form and that all the information we can have about a surface is the measurement data, which will include measurement uncertainty. Measurement data, or what will be referred to as the measured surface, is all that really exists. In this paper the basic physical differences between mechanically, electromagnetically and electrically measured surfaces are highlighted and discussed and accompanied by measurement results on a roughness artefact. (paper)

  13. Electric field vector measurements in a surface ionization wave discharge

    International Nuclear Information System (INIS)

    Goldberg, Benjamin M; Adamovich, Igor V; Lempert, Walter R; Böhm, Patrick S; Czarnetzki, Uwe

    2015-01-01

    This work presents the results of time-resolved electric field vector measurements in a short pulse duration (60 ns full width at half maximum), surface ionization wave discharge in hydrogen using a picosecond four-wave mixing technique. Electric field vector components are measured separately, using pump and Stokes beams linearly polarized in the horizontal and vertical planes, and a polarizer placed in front of the infrared detector. The time-resolved electric field vector is measured at three different locations across the discharge gap, and for three different heights above the alumina ceramic dielectric surface, ∼100, 600, and 1100 μm (total of nine different locations). The results show that after breakdown, the discharge develops as an ionization wave propagating along the dielectric surface at an average speed of 1 mm ns −1 . The surface ionization wave forms near the high voltage electrode, close to the dielectric surface (∼100 μm). The wave front is characterized by significant overshoot of both vertical and horizontal electric field vector components. Behind the wave front, the vertical field component is rapidly reduced. As the wave propagates along the dielectric surface, it also extends further away from the dielectric surface, up to ∼1 mm near the grounded electrode. The horizontal field component behind the wave front remains quite significant, to sustain the electron current toward the high voltage electrode. After the wave reaches the grounded electrode, the horizontal field component experiences a secondary rise in the quasi-dc discharge, where it sustains the current along the near-surface plasma sheet. The measurement results indicate presence of a cathode layer formed near the grounded electrode with significant cathode voltage fall, ≈3 kV, due to high current density in the discharge. The peak reduced electric field in the surface ionization wave is 85–95 Td, consistent with dc breakdown field estimated from the Paschen

  14. BMI calculation in older people: The effect of using direct and surrogate measures of height in a community-based setting.

    Science.gov (United States)

    Butler, Rose; McClinchy, Jane; Morreale-Parker, Claudia; Marsh, Wendy; Rennie, Kirsten L

    2017-12-01

    There is currently no consensus on which measure of height should be used in older people's body mass index (BMI) calculation. Most estimates of nutritional status include a measurement of body weight and height which should be reliable and accurate, however at present several different methods are used interchangeably. BMI, a key marker in malnutrition assessment, does not reflect age-related changes in height or changes in body composition such as loss of muscle mass or presence of oedema. The aim of this pilot study was to assess how the use of direct and surrogate measures of height impacts on BMI calculation in people aged ≥75 years. A cross-sectional study of 64 free-living older people (75-96 yrs) quantified height by two direct measurements, current height (H C ), and self-report (H R ) and surrogate equations using knee height (H K ) and ulna length (H U ). BMI calculated from current height measurement (BMI C ) was compared with BMI calculated using self-reported height (BMI R ) and height estimated from surrogate equations for knee height (BMI K ) and ulna length (BMI U ). Median difference of BMI C -BMI R was 2.31 kg/m 2 . BMI K gave the closest correlation to BMI C . The percentage of study participants identified at increased risk of under-nutrition (BMI BMI; from 5% (BMI C ), 7.8% (BMI K ), 12.5% (BMI U ), to 14% (BMI R ) respectively. The results of this pilot study in a relatively healthy sample of older people suggest that interchangeable use of current and reported height in people ≥75 years can introduce substantial significant systematic error. This discrepancy could impact nutritional assessment of older people in poor health and lead to misclassification during nutritional screening if other visual and clinical clues are not taken into account. This could result in long-term clinical and cost implications if individuals who need nutrition support are not correctly identified. A consensus is required on which method should be used to

  15. Surface resistivity measurement of plasma treated polymers

    International Nuclear Information System (INIS)

    Simon, D.; Pigram, P.J.; Liesegang, J.

    2000-01-01

    Full text: Resistivity of insulators is an important property of materials used within the integrated circuit and packaging industries. The measurement of electrical resistivity of insulator materials in the surface region in this work is interpreted through observations of surface charge decay. A self-field driven and diffusion charge transport theory is used to model the process and resistivity values obtained computationally. Data for the charge decay of surface charged samples are collected by suspending them inside a coaxial cylinder connected to an electrometer. Samples used have been low density polyethylene LDPE sheet, both pristine and surface treated. Some samples have been treated by air plasma at low vacuum pressures for different periods of time; others have been washed in ethyl acetate and then plasma treated before the resistivity measurement. The sets of resistivity measurements form the various treatments are compared below. X-ray photoelectron spectroscopy (XPS) has also been used to investigate and account for the observed variations in surface resistivity

  16. Surface Tension Measurements with a Smartphone

    Science.gov (United States)

    Goy, Nicolas-Alexandre; Denis, Zakari; Lavaud, Maxime; Grolleau, Adrian; Dufour, Nicolas; Deblais, Antoine; Delabre, Ulysse

    2017-01-01

    Smartphones are increasingly used in higher education and at university in mechanics, acoustics, and even thermodynamics as they offer a unique way to do simple science experiments. In this article, we show how smartphones can be used in fluid mechanics to measure surface tension of various liquids, which could help students understand the concept…

  17. Surface charge measurement using an electrostatic probe

    DEFF Research Database (Denmark)

    Crichton, George C; McAllister, Iain Wilson

    1998-01-01

    During the 1960s, the first measurements of charge on dielectric surfaces using simple electrostatic probes were reported. However it is only within the last 10 years that a proper understanding of the probe response has been developed. This situation arose as a consequence of the earlier studies...

  18. Optical measurement of surface roughness in manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Brodmann, R.

    1984-11-01

    The measuring system described here is based on the light-scattering method, and was developed by Optische Werke G. Rodenstock, Munich. It is especially useful for rapid non-contact monitoring of surface roughness in production-related areas. This paper outlines the differences between this system and the common stylus instrument, including descriptions of some applications in industry.

  19. Surface measurement errors using commercial scanning white light interferometers

    International Nuclear Information System (INIS)

    Gao, F; Petzing, J; Coupland, J M; Leach, R K

    2008-01-01

    This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required

  20. Surface measurement errors using commercial scanning white light interferometers

    Science.gov (United States)

    Gao, F.; Leach, R. K.; Petzing, J.; Coupland, J. M.

    2008-01-01

    This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required.

  1. Surface dose extrapolation measurements with radiographic film

    International Nuclear Information System (INIS)

    Butson, Martin J; Cheung Tsang; Yu, Peter K N; Currie, Michael

    2004-01-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. (note)

  2. Novel surface measurement system reading cost savings

    Energy Technology Data Exchange (ETDEWEB)

    Sword, M.

    1996-05-01

    A new state-of-the-art data acquisition system for the oil and natural gas industries is being marketed by OPSCO`92 Industries Ltd. The unit is portable, it measures surface data which is calibrated to bottom-hole conditions and designed to measure temperature and pressure information without the necessity of sending testing equipment downhole. The Surface Data System (SDS) uses silicon-crystal technology, is mounted in a suitcase size carrying case, and runs off a 12-volt battery enclosure which can be backed up by a small solar panel. The first generation system can handle 16 different channels of information input on a laptop computer. Pressure, pressure differential, temperature, frequency and pulse signals for flow meter measurements are handled by standard sensors. Areas of application include build-up and fall-off tests, pipeline evaluation, pre-frac tests, underbalanced drilling and gas well evaluation. 1 fig., 1 photo.

  3. Comparison of slope and height profiles for flat synchrotron x-ray mirrors measured with a long trace profiler and a Fizeau interferometer

    International Nuclear Information System (INIS)

    Qian, J.; Assoufid, L.; Macrander, A.

    2007-01-01

    Long trace profilers (LTPS) have been used at many synchrotron radiation laboratories worldwide for over a decade to measure surface slope profiles of long grazing incidence x-ray mirrors. Phase measuring interferometers (PMIs) of the Fizeau type, on the other hand, are being used by most mirror manufacturers to accomplish the same task. However, large mirrors whose dimensions exceed the aperture of the Fizeau interferometer require measurements to be carried out at grazing incidence, and aspheric optics require the use of a null lens. While an LTP provides a direct measurement of ID slope profiles, PMIs measure area height profiles from which the slope can be obtained by a differentiation algorithm. Measurements of the two types of instruments have been found by us to be in good agreement, but to our knowledge there is no published work directly comparing the two instruments. This paper documents that comparison. We measured two different nominally flat mirrors with both the LTP in operation at the Advanced Photon Source (a type-II LTP) and a Fizeau-type PMI interferometer (Wyko model 6000). One mirror was 500 mm long and made of Zerodur, and the other mirror was 350 mm long and made of silicon. Slope error results with these instruments agree within nearly 100% (3.11 ± 0.15 (micro)rad for the LTP, and 3.11 ± 0.02 (micro)rad for the Fizeau PMI interferometer) for the medium quality Zerodur mirror with 3 (micro)rad rms nominal slope error. A significant difference was observed with the much higher quality silicon mirror. For the Si mirror, slope error data is 0.39 ± 0.08 (micro)rad from LTP measurements but it is 0.35 ± 0.01 (micro)rad from PMI interferometer measurements. The standard deviations show that the Fizeau PMI interferometer has much better measurement repeatability.

  4. Comparison of Cloud Base Height Derived from a Ground-Based Infrared Cloud Measurement and Two Ceilometers

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2015-01-01

    Full Text Available The cloud base height (CBH derived from the whole-sky infrared cloud-measuring system (WSIRCMS and two ceilometers (Vaisala CL31 and CL51 from November 1, 2011, to June 12, 2012, at the Chinese Meteorological Administration (CMA Beijing Observatory Station are analysed. Significant differences can be found by comparing the measurements of different instruments. More exactly, the cloud occurrence retrieved from CL31 is 3.8% higher than that from CL51, while WSIRCMS data shows 3.6% higher than ceilometers. More than 75.5% of the two ceilometers’ differences are within ±200 m and about 89.5% within ±500 m, while only 30.7% of the differences between WSIRCMS and ceilometers are within ±500 m and about 55.2% within ±1000 m. These differences may be caused by the measurement principles and CBH retrieval algorithm. A combination of a laser ceilometer and an infrared cloud instrument is recommended to improve the capability for determining cloud occurrence and retrieving CBHs.

  5. Influence of pulse-height discrimination threshold for photon counting on the accuracy of singlet oxygen luminescence measurement

    International Nuclear Information System (INIS)

    Lin, Huiyun; Chen, Defu; Wang, Min; Lin, Juqiang; Li, Buhong; Xie, Shusen

    2011-01-01

    Direct measurement of near-infrared (NIR) luminescence around 1270 nm is the golden standard of singlet oxygen ( 1 O 2 ) identification. In this study, the influence of pulse-height discrimination threshold on measurement accuracy of the 1 O 2 luminescence that is generated from the photoirradiation of meso-tetra (N-methyl-4-pyridyl) morphine tetra-tosylate (TMPyP) in aqueous solution was investigated by using our custom-developed detection system. Our results indicate that the discrimination threshold has a significant influence on the absolute 1 O 2 luminescence counts, and the optimal threshold for our detection system is found to be about − 41.2 mV for signal discrimination. After optimization, the derived triplet-state and 1 O 2 lifetimes of TMPyP in aqueous solution are found to be 1.73 ± 0.03 and 3.70 ± 0.04 µs, respectively, and the accuracy of measurement was further independently demonstrated using the laser flash photolysis technique

  6. Influence of pulse-height discrimination threshold for photon counting on the accuracy of singlet oxygen luminescence measurement

    Science.gov (United States)

    Lin, Huiyun; Chen, Defu; Wang, Min; Lin, Juqiang; Li, Buhong; Xie, Shusen

    2011-12-01

    Direct measurement of near-infrared (NIR) luminescence around 1270 nm is the golden standard of singlet oxygen (1O2) identification. In this study, the influence of pulse-height discrimination threshold on measurement accuracy of the 1O2 luminescence that is generated from the photoirradiation of meso-tetra (N-methyl-4-pyridyl) morphine tetra-tosylate (TMPyP) in aqueous solution was investigated by using our custom-developed detection system. Our results indicate that the discrimination threshold has a significant influence on the absolute 1O2 luminescence counts, and the optimal threshold for our detection system is found to be about - 41.2 mV for signal discrimination. After optimization, the derived triplet-state and 1O2 lifetimes of TMPyP in aqueous solution are found to be 1.73 ± 0.03 and 3.70 ± 0.04 µs, respectively, and the accuracy of measurement was further independently demonstrated using the laser flash photolysis technique.

  7. Unexpected Covariant Behavior of the Aegean and Ionian Seas in the Period 1987-2008 by Means of a Nondimensional Sea Surface Height Index

    Science.gov (United States)

    Reale, M.; Salon, S.; Crise, A.; Farneti, R.; Mosetti, R.; Sannino, G.

    2017-10-01

    In this work, we use a set of recent multiyear simulations to develop a simplified sea surface height index (SSH). The index characterizes the dynamics of Ionian upper layer circulation and its links with sea surface height and salinity in the Southern Adriatic and Aegean Seas during the period 1987-2008. The analysis highlights a covariant behavior between Ionian Sea and Aegean Sea associated with a mutual zonal exchange of water masses with different salinity characteristics. Our analysis confirms that the variability observed in the period 1987-2008 in the upper layer circulation of the Ionian was driven by the salinity variability in the Southern Adriatic and Aegean Sea. This study supports and reinforces the hypothesis that two observed BiOS-like reversals reflect the existence of multiple equilibrium states in the Mediterranean Thermohaline circulation in the Eastern Mediterranean and that a complete characterization of observed variability needs to take into account a fully coupled Adriatic-Ionian-Aegean System.

  8. Minimizing Uncertainty in Cryogenic Surface Figure Measurement

    Science.gov (United States)

    Blake, Peter; Mink, Ronald G.; Chambers, John; Robinson, F. David; Content, David; Davila, Pamela

    2005-01-01

    A new facility at the Goddard Space Flight Center is designed to measure with unusual accuracy the surface figure of mirrors at cryogenic temperatures down to 12 K. The facility is currently configured for spherical mirrors with a radius of curvature (ROC) of 600 mm, and apertures of about 150 mm or less. The goals of the current experiment were to 1) Obtain the best possible estimate of test mirror surface figure, S(x,y) at 87 K and 20 K; 2) Obtain the best estimate of the cryo-change, Delta (x,y): the change in surface figure between room temperature and the two cryo-temperatures; and 3) Determine the uncertainty of these measurements, using the definitions and guidelines of the ISO Guide to the Expression of Uncertainty in Measurement. A silicon mirror was tested, and the cry-change from room temperature to 20K was found to be 3.7 nm rms, with a standard uncertainty of 0.23 nm in the rms statistic. Both the cryo-change figure and the uncertainty are among the lowest such figures yet published. This report describes the facilities, experimental methods, and uncertainty analysis of the measurements.

  9. Wuthering Heights

    NARCIS (Netherlands)

    Bronte, Emily

    2005-01-01

    Wuthering Heights tells the story of a romance between two youngsters: Catherine Earnshaw and an orphan boy, Heathcliff. After she rejects him for a boy from a better background he develops a lust for revenge that takes over his life. In attempting to win her back and destroy those he blames for his

  10. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2016-07-21

    We evaluate the sensitivity of simulated turbine-height winds to 26 parameters applied in a planetary boundary layer (PBL) scheme and a surface layer scheme of the Weather Research and Forecasting (WRF) model over an area of complex terrain during the Columbia Basin Wind Energy Study. An efficient sampling algorithm and a generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of modeled turbine-height winds. The results indicate that most of the variability in the ensemble simulations is contributed by parameters related to the dissipation of the turbulence kinetic energy (TKE), Prandtl number, turbulence length scales, surface roughness, and the von Kármán constant. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability. The parameter associated with the TKE dissipation rate is found to be the most important one, and a larger dissipation rate can produce larger hub-height winds. A larger Prandtl number results in weaker nighttime winds. Increasing surface roughness reduces the frequencies of both extremely weak and strong winds, implying a reduction in the variability of the wind speed. All of the above parameters can significantly affect the vertical profiles of wind speed, the altitude of the low-level jet and the magnitude of the wind shear strength. The wind direction is found to be modulated by the same subset of influential parameters. Remainder of abstract is in attachment.

  11. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Science.gov (United States)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2017-01-01

    We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.

  12. Effect of Channel Orientation and Rib Pitch-to-Height Ratio on Pressure Drop in a Rotating Square Channel with Ribs on Two Opposite Surfaces

    Directory of Open Access Journals (Sweden)

    Prabhu S. V.

    2005-01-01

    Full Text Available The effect of channel orientation and rib pitch-to-height ratio on the pressure drop distribution in a rib-roughened channel is an important issue in turbine blade cooling. The present investigation is a study of the overall pressure drop distribution in a square cross-sectioned channel, with rib turbulators, rotating about an axis normal to the free stream. The ribs are configured in a symmetric arrangement on two opposite surfaces with a rib angle of 90 ∘ to the mainstream flow. The study has been conducted for three Reynolds numbers, namely, 13 000, 17 000, and 22 000 with the rotation number varying from 0– 0.38 . Experiments have been carried out for various rib pitch-to-height ratios ( P/e with a constant rib height-to-hydraulic diameter ratio ( e/D of 0.1 . The test section in which the ribs are placed on the leading and trailing surfaces is considered as the base case ( orientation angle= 0 ∘ , Coriolis force vector normal to the ribbed surfaces. The channel is turned about its axis in steps of 15 ∘ to vary the orientation angle from 0 ∘ to 90 ∘ . The overall pressure drop does not change considerably under conditions of rotation for the base case. However, for the other cases tested, it is observed that the overall pressure drop increases with an increase in the rotation number for a given orientation angle and also increases with an increase in the orientation angle for a given rotation number. This change is attributed to the variation in the separation zone downstream of the ribs due to the presence of the Coriolis force—local pressure drop data is presented which supports this idea. At an orientation angle of 90 ∘ (ribs on the top and bottom surfaces, Coriolis force vector normal to the smooth surfaces, the overall pressure drop is observed to be maximum during rotation. The overall pressure drop for a case with a rib pitch-to-height ratio of 5 on both surfaces is found to be the highest

  13. Measurements of land surface features using an airborne laser altimeter: the HAPEX-Sahel experiment

    International Nuclear Information System (INIS)

    Ritchie, J.C.; Menenti, M.; Weltz, M.A.

    1997-01-01

    An airborne laser profiling altimeter was used to measure surface features and properties of the landscape during the HAPEX-Sahel Experiment in Niger, Africa in September 1992. The laser altimeter makes 4000 measurements per second with a vertical resolution of 5 cm. Airborne laser and detailed field measurements of vegetation heights had similar average heights and frequency distribution. Laser transects were used to estimate land surface topography, gully and channel morphology, and vegetation properties ( height, cover and distribution). Land surface changes related to soil erosion and channel development were measured. For 1 km laser transects over tiger bush communities, the maximum vegetation height was between 4-5 and 6-5 m, with an average height of 21 m. Distances between the centre of rows of tiger bush vegetation averaged 100 m. For two laser transects, ground cover for tiger bush was estimated to be 225 and 301 per cent for vegetation greater than 0-5m tall and 190 and 25-8 per cent for vegetation greater than 10m tall. These values are similar to published values for tiger bush. Vegetation cover for 14 and 18 km transects was estimated to be 4 per cent for vegetation greater than 0-5 m tall. These cover values agree within 1-2 per cent with published data for short transects (⩾ 100 m) for the area. The laser altimeter provided quick and accurate measurements for evaluating changes in land surface features. Such information provides a basis for understanding land degradation and a basis for management plans to rehabilitate the landscape. (author)

  14. Radioimmunoassay to quantitatively measure cell surface immunoglobulins

    International Nuclear Information System (INIS)

    Krishman, E.C.; Jewell, W.R.

    1975-01-01

    A radioimmunoassay techniques developed to quantitatively measure the presence of immunoglobulins on the surface of cells, is described. The amount of immunoglobulins found on different tumor cells varied from 200 to 1140 ng/10 6 cells. Determination of immunoglobulins on the peripheral lymphocytes obtained from different cancer patients varied between 340 to 1040 ng/10 6 cells. Cultured tumor cells, on the other hand, were found to contain negligible quantities of human IgG [pt

  15. Description of measurement techniques for surface contaminations

    International Nuclear Information System (INIS)

    Bourrez, E.

    2001-01-01

    The needs of evaluation of the surface contamination are numerous in the processes of production and management of radioactive waste. The market of radiation protection materials proposes a lot of devices answering to the almost all these needs. These device have however their conditions and particular limits for use. To realize correct measurements it is use the device, the technique and the methods adapted to the need, by taking into account the optimization of economical aspect. (N.C.)

  16. Investigation of the mixing layer height derived from ceilometer measurements in the Kathmandu Valley and implications for local air quality

    Directory of Open Access Journals (Sweden)

    A. Mues

    2017-07-01

    Full Text Available In this study 1 year of ceilometer measurements taken in the Kathmandu Valley, Nepal, in the framework of the SusKat project (A Sustainable Atmosphere for the Kathmandu Valley were analysed to investigate the diurnal variation of the mixing layer height (MLH and its dependency on the meteorological conditions. In addition, the impact of the MLH on the temporal variation and the magnitude of the measured black carbon concentrations are analysed for each season. Based on the assumption that black carbon aerosols are vertically well mixed within the mixing layer and the finding that the mixing layer varies only little during night time and morning hours, black carbon emission fluxes are estimated for these hours and per month. Even though this method is relatively simple, it can give an observationally based first estimate of the black carbon emissions in this region, especially illuminating the seasonal cycle of the emission fluxes. The monthly minimum median MLH values typically range between 150 and 200 m during night and early morning hours, the monthly maximum median values between 625 m in July and 1460 m in March. Seasonal differences are not only found in the absolute MLHs, but also in the duration of the typical daytime maximum ranging between 2 and 3 h in January and 6–7 h in May. During the monsoon season a diurnal cycle has been observed with the smallest amplitude (typically between 400 and 500 m, with the lowest daytime mixing height of all seasons (maximum monthly median values typically between 600 and 800 m, and also the highest night-time and early morning mixing height of all seasons (minimum monthly median values typically between 200 and 220 m. These characteristics can mainly be explained with the frequently present clouds and the associated reduction in incoming solar radiation and outgoing longwave radiation. In general, the black carbon concentrations show a clear anticorrelation with MLH measurements

  17. Polarization optics of the Brewster's dark patch visible on water surfaces versus solar height and sky conditions: theory, computer modeling, photography, and painting.

    Science.gov (United States)

    Takács, Péter; Barta, András; Pye, David; Horváth, Gábor

    2017-10-20

    When the sun is near the horizon, a circular band with approximately vertically polarized skylight is formed at 90° from the sun, and this skylight is only weakly reflected from the region of the water surface around the Brewster's angle (53° from the nadir). Thus, at low solar heights under a clear sky, an extended dark patch is visible on the water surface when one looks toward the north or south quarter perpendicular to the solar vertical. In this work, we study the radiance distribution of this so-called Brewster's dark patch (BDP) in still water as functions of the solar height and sky conditions. We calculate the pattern of reflectivity R of a water surface for a clear sky and obtain from this idealized situation the shape of the BDP. From three full-sky polarimetric pictures taken about a clear, a partly cloudy, and an overcast sky, we determine the R pattern and compose from that synthetic color pictures showing how the radiance distribution of skylight reflected at the water surface and the BDPs would look under these sky conditions. We also present photographs taken without a linearly polarizing filter about the BDP. Finally, we show a 19th century painting on which a river is seen with a dark region of the water surface, which can be interpreted as an artistic illustration of the BDP.

  18. Acoustic Impedance Measurement for Underground Surfaces.

    Science.gov (United States)

    Cockcroft, Paul William

    Available from UMI in association with The British Library. Requires signed TDF. This thesis investigates the measurement of acoustic impedance for surfaces likely to be found in underground coal mines. By introducing the concepts of industrial noise, the effects of noise on the ear and relevant legislation the need for the protection of workers can be appreciated. Representative acoustic impedance values are vital as input for existing computer models that predict sound levels in various underground environments. These enable the mining engineer to predict the noise level at any point within a mine in the vicinity of noisy machinery. The concepts of acoustic intensity and acoustic impedance are investigated and different acoustic impedance measurement techniques are detailed. The possible use of either an impedance tube or an intensity meter for these kinds of measurements are suggested. The problems with acoustic intensity and acoustic impedance measurements are discussed with reference to the restraints that an underground environment imposes on any measurement technique. The impedance tube method for work in an acoustics laboratory is shown and the theory explained, accompanied by a few representative results. The use of a Metravib intensity meter in a soundproof chamber to gain impedance values is explained in detail. The accompanying software for the analysis of the two measured pressure signals is shown as well as the actual results for a variety of test surfaces. The use of a Nagra IV-SJ tape recorder is investigated to determine the effect of recording on the measurement and subsequent analysis of the input signals, particularly with reference to the phase difference introduced between the two simultaneous pressure signals. The subsequent use of a Norwegian Electronic intensity meter, including a proposal for underground work, is shown along with results for tests completed with this piece of equipment. Finally, recommendations are made on how to link up

  19. Application of the Same Beam Interferometry Measurement in Relative Position Determination on Lunar Surface

    Directory of Open Access Journals (Sweden)

    HUANG Anyi

    2015-09-01

    Full Text Available Based on the principle and observation model of the same beam interferometry measurement, observation equations of differential time delay and time delay rate for targets on lunar surface are proposed. Restriction of appointed height and digital lunar height model is introduced and a Kalman filter with restriction to determine the relative position is put forward. By data simulation, the arithmetic is then validated and evaluated, which could fleetly and accurately determine the relative position between rover and lander. Low precision of the lander's position is required in the calculation.

  20. Impact of soil moisture and winter wheat height from the Loess Plateau in Northwest China on surface spectral albedo

    Science.gov (United States)

    Li, Zhenchao; Yang, Jiaxi; Gao, Xiaoqing; Zheng, Zhiyuan; Yu, Ye; Hou, Xuhong; Wei, Zhigang

    2018-02-01

    The understanding of surface spectral radiation and reflected radiation characteristics of different surfaces in different climate zones aids in the interpretation of regional surface energy transfers and the development of land surface models. This study analysed surface spectral radiation variations and corresponding surface albedo characteristics at different wavelengths as well as the relationship between 5-cm soil moisture and surface albedo on typical sunny days during the winter wheat growth period. The analysis was conducted using observational Loess Plateau winter wheat data from 2015. The results show that the ratio of atmospheric downward radiation to global radiation on typical sunny days is highest for near-infrared wavelengths, followed by visible wavelengths and ultraviolet wavelengths, with values of 57.3, 38.7 and 4.0%, respectively. The ratio of reflected spectral radiation to global radiation varies based on land surface type. The visible radiation reflected by vegetated surfaces is far less than that reflected by bare ground, with surface albedos of 0.045 and 0.27, respectively. Thus, vegetated surfaces absorb more visible radiation than bare ground. The atmospheric downward spectral radiation to global radiation diurnal variation ratios vary for near-infrared wavelengths versus visible and ultraviolet wavelengths on typical sunny days. The near-infrared wavelengths ratio is higher in the morning and evening and lower at noon. The visible and ultraviolet wavelengths ratios are lower in the morning and evening and higher at noon. Visible and ultraviolet wavelength surface albedo is affected by 5-cm soil moisture, demonstrating a significant negative correlation. Excluding near-infrared wavelengths, correlations between surface albedo and 5-cm soil moisture pass the 99% confidence test at each wavelength. The correlation with 5-cm soil moisture is more significant at shorter wavelengths. However, this study obtained surface spectral radiation

  1. The reliability of in-home measures of height and weight in large cohort studies: Evidence from Add Health

    Directory of Open Access Journals (Sweden)

    Jon Hussey

    2015-05-01

    Full Text Available Background: With the emergence of obesity as a global health issue, an increasing number of major demographic surveys are collecting measured anthropometric data. Yet little is known about the characteristics and reliability of these data. Objective: We evaluate the accuracy and reliability of anthropometric data collected in the home during Wave IV of the National Longitudinal Study of Adolescent to Adult Health (Add Health, compare our estimates to national standard, clinic-based estimates from the National Health and Nutrition Examination Survey (NHANES and, using both sources, provide a detailed anthropometric description of young adults in the United States. Methods: The reliability of Add Health in-home anthropometric measures was estimated from repeat examinations of a random subsample of study participants. A digit preference analysis evaluated the quality of anthropometric data recorded by field interviewers. The adjusted odds of obesity and central obesity in Add Health vs. NHANES were estimated with logistic regression. Results: Short-term reliabilities of in-home measures of height, weight, waist and arm circumference - as well as derived body mass index (BMI, kg/m2 - were excellent. Prevalence of obesity (37Š vs. 29Š and central obesity (47Š vs. 38Š was higher in Add Health than in NHANES, while socio-demographic patterns of obesity and central obesity were comparable in the two studies. Conclusions: Properly trained non-medical field interviewers can collect reliable anthropometric data in a nationwide, home visit study. This national cohort of young adults in the United States faces a high risk of early-onset chronic disease and premature mortality.

  2. Evaluation and adjustment of altimeter measurement and numerical hindcast in wave height trend estimation in China's coastal seas

    Science.gov (United States)

    Li, Shuiqing; Guan, Shoude; Hou, Yijun; Liu, Yahao; Bi, Fan

    2018-05-01

    A long-term trend of significant wave height (SWH) in China's coastal seas was examined based on three datasets derived from satellite measurements and numerical hindcasts. One set of altimeter data were obtained from the GlobWave, while the other two datasets of numerical hindcasts were obtained from the third-generation wind wave model, WAVEWATCH III, forced by wind fields from the Cross-Calibrated Multi-Platform (CCMP) and NCEP's Climate Forecast System Reanalysis (CFSR). The mean and extreme wave trends were estimated for the period 1992-2010 with respect to the annual mean and the 99th-percentile values of SWH, respectively. The altimeter wave trend estimates feature considerable uncertainties owing to the sparse sampling rate. Furthermore, the extreme wave trend tends to be overestimated because of the increasing sampling rate over time. Numerical wave trends strongly depend on the quality of the wind fields, as the CCMP waves significantly overestimate the wave trend, whereas the CFSR waves tend to underestimate the trend. Corresponding adjustments were applied which effectively improved the trend estimates from the altimeter and numerical data. The adjusted results show generally increasing mean wave trends, while the extreme wave trends are more spatially-varied, from decreasing trends prevailing in the South China Sea to significant increasing trends mainly in the East China Sea.

  3. Measuring the Valence of Nanocrystal Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Jonathan Scharle [Columbia Univ., New York, NY (United States)

    2016-11-30

    The goal of this project is to understand and control the interplay between nanocrystal stoichiometry, surface ligand binding and exchange, and the optoelectronic properties of semiconductor nanocrystals in solution and in thin solid films. We pursued three research directions with this goal in mind: 1) We characterized nanocrystal stoichiometry and its influence on the binding of L-type and X-type ligands, including the thermodynamics of binding and the kinetics of ligand exchange. 2) We developed a quantitative understanding of the relationship between surface ligand passivation and photoluminescence quantum yield. 3) We developed methods to replace the organic ligands on the nanocrystal with halide ligands and controllably deposit these nanocrystals into thin films, where electrical measurements were used to investigate the electrical transport and internanocrystal electronic coupling.

  4. Lipoxin A4 stimulates calcium-activated chloride currents and increases airway surface liquid height in normal and cystic fibrosis airway epithelia.

    LENUS (Irish Health Repository)

    2012-01-01

    Cystic Fibrosis (CF) is a genetic disease characterised by a deficit in epithelial Cl(-) secretion which in the lung leads to airway dehydration and a reduced Airway Surface Liquid (ASL) height. The endogenous lipoxin LXA(4) is a member of the newly identified eicosanoids playing a key role in ending the inflammatory process. Levels of LXA(4) are reported to be decreased in the airways of patients with CF. We have previously shown that in normal human bronchial epithelial cells, LXA(4) produced a rapid and transient increase in intracellular Ca(2+). We have investigated, the effect of LXA(4) on Cl(-) secretion and the functional consequences on ASL generation in bronchial epithelial cells obtained from CF and non-CF patient biopsies and in bronchial epithelial cell lines. We found that LXA(4) stimulated a rapid intracellular Ca(2+) increase in all of the different CF bronchial epithelial cells tested. In non-CF and CF bronchial epithelia, LXA(4) stimulated whole-cell Cl(-) currents which were inhibited by NPPB (calcium-activated Cl(-) channel inhibitor), BAPTA-AM (chelator of intracellular Ca(2+)) but not by CFTRinh-172 (CFTR inhibitor). We found, using confocal imaging, that LXA(4) increased the ASL height in non-CF and in CF airway bronchial epithelia. The LXA(4) effect on ASL height was sensitive to bumetanide, an inhibitor of transepithelial Cl(-) secretion. The LXA(4) stimulation of intracellular Ca(2+), whole-cell Cl(-) currents, conductances and ASL height were inhibited by Boc-2, a specific antagonist of the ALX\\/FPR2 receptor. Our results provide, for the first time, evidence for a novel role of LXA(4) in the stimulation of intracellular Ca(2+) signalling leading to Ca(2+)-activated Cl(-) secretion and enhanced ASL height in non-CF and CF bronchial epithelia.

  5. Quality assurance of in-situ measurements of land surface albedo: A model-based approach

    Science.gov (United States)

    Adams, Jennifer; Gobron, Nadine; Widlowski, Jean-Luc; Mio, Corrado

    2016-04-01

    This paper presents the development of a model-based framework for assessing the quality of in-situ measurements of albedo used to validate land surface albedo products. Using a 3D Monte Carlo Ray Tracing (MCRT) radiative transfer model, a quality assurance framework is built based on simulated field measurements of albedo within complex 3D canopies and under various illumination scenarios. This method provides an unbiased approach in assessing the quality of field measurements, and is also able to trace the contributions of two main sources of uncertainty in field-measurements of albedo; those resulting from 1) the field measurement protocol, such as height or placement of field measurement within the canopy, and 2) intrinsic factors of the 3D canopy under specific illumination characteristics considered, such as the canopy structure and landscape heterogeneity, tree heights, ecosystem type and season.

  6. Value of Tree Measurements Made at Age 5 Years for Predicting the Height and Diameter Growth at Age 25 Years in Loblolly Pine Plantations

    Science.gov (United States)

    Allan E. Tiarks; Calvin E. Meier; V. Clark Baldwin; James D. Haywood

    1998-01-01

    Early growth measurements Of pine plantations are often used to predict the productivity of the stand later in the rotation when assessing the effect Of management on productivity. A loblolly pine (Pinus taeda L.) study established at 35 locations (2 to 3 plots/location) was used to test the relationship between height measurements at age 5 years...

  7. Measurement of the filling height of transient two-phase surge flows in pipelines by means of electronics; Messung der Fuellhoehe von transienten Zweiphasenschwallstroemungen in Rohrleitungen mittels Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, B.; Rockstroh, M. [Technische Univ. Dresden (Germany). Inst. fuer Energiemaschinen und Maschinenlabor

    1997-12-01

    The aim of the ultrasonic measurements was the determination of the time course of the level of a transient surge flow with swirl and waves in partly filled roughly horizontally laid pipelines. The running time of the ultrasonic waves from the test head to the liquid surface and back was measured for this purpose. The course of the stress was recorded digitally and was evaluated with the aid of software. Waves, swirl, turbulence of flow and introduced test bodies in the flow caused typical echoes, which had to be taken into account in the evaluation. As the test head was fitted on the outside of the pipe (clamp-on technique), the pipe wall thickness and the speed of sound in the pipe wall had to be included in the calculation of filling height by means of a correction. [Deutsch] Ziel der Ultraschallmessungen war die Bestimmung des zeitlichen Verlaufes der Fuellhoehe einer transienten, drall- und wellenbehafteten Schwallstroemung in teilgefuellten, etwa horizontal verlegten Rohrleitungen. Hierzu wurde die Laufzeit der Ultraschallwellen vom Pruefkopf zur Fluessigkeitsoberflaeche und zurueck gemessen. Die Laufzeit der Ultraschallwellen wurde auf eine quasi-analog elektrische Spannung abgebildet. Der Spannungsverlauf wurde digital aufgezeichnet und softwaregestuetzt ausgewertet. Wellen, Drall, Stroemungsturbulenzen sowie eingebrachte Pruefkoerper in der Stroemung hatten typische Echoerscheinungen zur Folge, die bei der Auswertung zu beruecksichtigen waren. Da der Pruefkopf aussen am Rohr angebracht war (clamp-on-Technik), musste die Rohrwandstaerke und die Schallgeschwindigkeit in der Rohrwandung mittels eines Korrekturgliedes in die Fuellhoehenberechnung eingezogen werden. (orig.)

  8. Evaluation of Arctic broadband surface radiation measurements

    Directory of Open Access Journals (Sweden)

    N. Matsui

    2012-02-01

    Full Text Available The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW and thermal infrared, or longwave (LW, radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers that keep sensors and shading devices trained on the sun along its diurnal path. High quality measurements require striking a balance between locating stations in a pristine undisturbed setting free of artificial blockage (such as from buildings and towers and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data in the Arctic include solar tracker malfunctions, rime/frost/snow deposition on the protective glass domes of the radiometers and operational problems due to limited operator access in extreme weather conditions. In this study, comparisons are made between the global and component sum (direct [vertical component] + diffuse SW measurements. The difference between these two quantities (that theoretically should be zero is used to illustrate the magnitude and seasonality of arctic radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both SW and LW measurements. Solutions to these operational problems that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols are proposed.

  9. Measurement of the interaction between the flow and the free surface of a liquid

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Koji [Univ. of Tokyo, Ibaraki (Japan); Schmidl, W.D.; Philip, O.G. [Texas A& M Univ., College Station, TX (United States)

    1995-09-01

    The interaction between the flow and free surface was evaluated measuring the velocity distribution and surface movement simultaneously. The test section was a rectangular tank having a free surface. A rectangular nozzle was set near the free surface, causing the wavy free surface condition. The flow under the free surface was visualized by a laser light sheet and small tracer particles. With image processing techniques, the movement of the free surface and the movement of the particles were simultaneously measured from the recorded images, resulting in the velocity distributions and surface locations. Then, the interactions between the flow and free surface were evaluated using the form of turbulent energy and surface-related turbulent values. By increasing the turbulent energy near the free surface, the fluctuations of the free surface height and the inclination of the free surface were increased. The higher fluctuation of horizontal velocity was related to the higher surface position and negative inclination. The image processing technique is found to be very useful to evaluate the interaction between free surface and flow.

  10. Shallow Water Measurements Using a Single Green Laser Corrected by Building a Near Water Surface Penetration Model

    Directory of Open Access Journals (Sweden)

    Jianhu Zhao

    2017-04-01

    Full Text Available To reduce the size and cost of an integrated infrared (IR and green airborne LiDAR bathymetry (ALB system, and improve the accuracy of the green ALB system, this study proposes a method to accurately determine water surface and water bottom heights using a single green laser corrected by the near water surface penetration (NWSP model. The factors that influence the NWSP of green laser are likewise analyzed. In addition, an NWSP modeling method is proposed to determine the relationship between NWSP and the suspended sediment concentration (SSC of the surface layer, scanning angle of a laser beam and sensor height. The water surface and water bottom height models are deduced by considering NWSP and using only green laser based on the measurement principle of the IR laser and green laser, as well as employing the relationship between NWSP and the time delay of the surface return of the green laser. Lastly, these methods and models are applied to a practical ALB measurement. Standard deviations of 3.0, 5.3, and 1.3 cm are obtained by the NWSP, water-surface height, and water-bottom height models, respectively. Several beneficial conclusions and recommendations are drawn through the experiments and discussions.

  11. A Bayesian inversion framework for yield and height-of-burst/depth-of-burial for near-surface explosions

    Energy Technology Data Exchange (ETDEWEB)

    Johannesson, Gardar [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bulaevskaya, Vera [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ramirez, Abe [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ford, Sean [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rodgers, Artie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-07

    A Bayesian inversion framework is presented to estimate the yield of an explosion and height-of-burst/depth-of-burial (HOB/DOB) using seismic and air pressure data. This is accomplished by first calibrating the parameters in the forward models that relate the observations to the yield and HOB/DOB and then using the calibrated model to estimate yield and HOB/DOB associated with a new set of seismic and air pressure observations. The MCMC algorithms required to perform these steps are outlined, and the results with real data are shown. Finally, an extension is proposed for a case when clustering in the seismic displacement occurs as a function of different types of rock and other factors.

  12. Measuring the bias, precision, accuracy, and validity of self-reported height and weight in assessing overweight and obesity status among adolescents using a surveillance system

    Science.gov (United States)

    2015-01-01

    Background Evidence regarding bias, precision, and accuracy in adolescent self-reported height and weight across demographic subpopulations is lacking. The bias, precision, and accuracy of adolescent self-reported height and weight across subpopulations were examined using a large, diverse and representative sample of adolescents. A second objective was to develop correction equations for self-reported height and weight to provide more accurate estimates of body mass index (BMI) and weight status. Methods A total of 24,221 students from 8th and 11th grade in Texas participated in the School Physical Activity and Nutrition (SPAN) surveillance system in years 2000–2002 and 2004–2005. To assess bias, the differences between the self-reported and objective measures, for height and weight were estimated. To assess precision and accuracy, the Lin’s concordance correlation coefficient was used. BMI was estimated for self-reported and objective measures. The prevalence of students’ weight status was estimated using self-reported and objective measures; absolute (bias) and relative error (relative bias) were assessed subsequently. Correction equations for sex and race/ethnicity subpopulations were developed to estimate objective measures of height, weight and BMI from self-reported measures using weighted linear regression. Sensitivity, specificity and positive predictive values of weight status classification using self-reported measures and correction equations are assessed by sex and grade. Results Students in 8th- and 11th-grade overestimated their height from 0.68cm (White girls) to 2.02 cm (African-American boys), and underestimated their weight from 0.4 kg (Hispanic girls) to 0.98 kg (African-American girls). The differences in self-reported versus objectively-measured height and weight resulted in underestimation of BMI ranging from -0.23 kg/m2 (White boys) to -0.7 kg/m2 (African-American girls). The sensitivity of self-reported measures to classify weight

  13. Seasonal slope surface deformation measured with TLS

    International Nuclear Information System (INIS)

    Fan, L; Smethurst, J; Powrie, W; Sellaiya, A

    2014-01-01

    In temperate European climates, soil water removal due to vegetation transpiration peaks in summer and soil rewetting from higher levels of precipitation occurs in winter. In clays of high plasticity, the seasonal cycles of drying and wetting cause the soil to experience a volumetric change, resulting in seasonal shrinking and swelling. For a clay slope exhibiting volume change, such behaviour can lead to excessive deformation and could contribute to strain-softening and progressive slope failure. This can in turn cause traffic disruption and loss of life if roads and railways are founded on or surrounded by such slopes. This paper discusses the driving forces of seasonal surface movement, in particular the role of vegetation, and presents the use of Terrestrial Laser Scanning (TLS) to measure the surface movement of a lightly vegetated London Clay slope near Newbury, UK. Two TLS scans were carried out in early and late summer respectively, representing relative wet and dry conditions of the slope. Continuous field measurements of soil water content in upper layers of the slope were obtained from TDR ThetaProbes already installed at the site. The water content data are used to support the results obtained from TLS by indicating the likely volumetric change in the soil due to loss of water

  14. Sea Surface Temperatures (SST): Significance and Measurement

    Science.gov (United States)

    Singer, S. F.

    2006-05-01

    Oceans cover 71 percent of Earth's surface and control the global climate. Quoted global mean temperature values and trends, largely based on land thermometers, differ substantially -" mainly because of uncertainties about SST. The ongoing controversy about the relative importance of natural climate changes and Anthropogenic Global Warming (AGW) revolves mainly around disparities between temperature trends of the atmosphere and surface (in the tropics and SH, i.e. mostly SST). Accurate measurement of SST is difficult. Geographic coverage is poor and there are many different techniques, each with its own problems and uncertainties: Water temperatures from buckets and ship-engine inlets; fixed and floating buoys; air temperatures from shipboard and island stations; and remote sensing from satellites using IR and microwaves. As is evident, each technique refers to a different level below the air-water interface. Drifter buoys (at around 50 cm) measure temperatures in the euphotic layers that are generally warmer than the bulk mixed layer sampled by ships (typically around 10 m). The IR emission arises from a 10-micron-thick skin that interacts dynamically with the underlying "mixed layer." The microwave data depend also on emissivity and therefore on surface roughness and sea state. SST data derived from corals provide some support for instrumental data but are not conclusive. The majority of corals show a warming trend since 1979; others show cooling or are ambiguous. There are different ways of interpreting this result. Physical optics dictates that the downwelling IR radiation from atmospheric greenhouse gases is absorbed in the first instance within the skin. Only direct measurements can establish how much of this energy is shared with the bulk mixed layer (to which the usual SST values refer.). SST controls evaporation and therefore global precipitation. SST influences tropical cyclones and sea-level rise; but there is lively debate on those issues. Changes in

  15. An exploratory study on the aerosol height retrieval from OMI measurements of the 477 nm O2 - O2 spectral band using a neural network approach

    Science.gov (United States)

    Chimot, Julien; Pepijn Veefkind, J.; Vlemmix, Tim; de Haan, Johan F.; Amiridis, Vassilis; Proestakis, Emmanouil; Marinou, Eleni; Levelt, Pieternel F.

    2017-03-01

    This paper presents an exploratory study on the aerosol layer height (ALH) retrieval from the OMI 477 nm O2 - O2 spectral band. We have developed algorithms based on the multilayer perceptron (MLP) neural network (NN) approach and applied them to 3-year (2005-2007) OMI cloud-free scenes over north-east Asia, collocated with MODIS Aqua aerosol product. In addition to the importance of aerosol altitude for climate and air quality objectives, our long-term motivation is to evaluate the possibility of retrieving ALH for potential future improvements of trace gas retrievals (e.g. NO2, HCHO, SO2) from UV-visible air quality satellite measurements over scenes including high aerosol concentrations. This study presents a first step of this long-term objective and evaluates, from a statistic point of view, an ensemble of OMI ALH retrievals over a long time period of 3 years covering a large industrialized continental region. This ALH retrieval relies on the analysis of the O2 - O2 slant column density (SCD) and requires an accurate knowledge of the aerosol optical thickness, τ. Using MODIS Aqua τ(550 nm) as a prior information, absolute seasonal differences between the LIdar climatology of vertical Aerosol Structure for space-based lidar simulation (LIVAS) and average OMI ALH, over scenes with MODIS τ(550 nm) ≥ 1. 0, are in the range of 260-800 m (assuming single scattering albedo ω0 = 0. 95) and 180-310 m (assuming ω0 = 0. 9). OMI ALH retrievals depend on the assumed aerosol single scattering albedo (sensitivity up to 660 m) and the chosen surface albedo (variation less than 200 m between OMLER and MODIS black-sky albedo). Scenes with τ ≤ 0. 5 are expected to show too large biases due to the little impact of particles on the O2 - O2 SCD changes. In addition, NN algorithms also enable aerosol optical thickness retrieval by exploring the OMI reflectance in the continuum. Comparisons with collocated MODIS Aqua show agreements between -0. 02 ± 0. 45 and -0. 18 ± 0

  16. Quadrotor helicopter for surface hydrological measurements

    Science.gov (United States)

    Pagano, C.; Tauro, F.; Porfiri, M.; Grimaldi, S.

    2013-12-01

    Surface hydrological measurements are typically performed through user-assisted and intrusive field methodologies which can be inadequate to monitor remote and extended areas. In this poster, we present the design and development of a quadrotor helicopter equipped with digital acquisition system and image calibration units for surface flow measurements. This custom-built aerial vehicle is engineered to be lightweight, low-cost, highly customizable, and stable to guarantee optimal image quality. Quadricopter stability guarantees minimal vibrations during image acquisition and, therefore, improved accuracy in flow velocity estimation through large scale particle image velocimetry algorithms or particle tracking procedures. Stability during the vehicle pitching and rolling is achieved by adopting large arm span and high-wing configurations. Further, the vehicle framework is composed of lightweight aluminum and durable carbon fiber for optimal resilience. The open source Ardupilot microcontroller is used for remote control of the quadricopter. The microcontroller includes an inertial measurement unit (IMU) equipped with accelerometers and gyroscopes for stable flight through feedback control. The vehicle is powered by a 3 cell (11.1V) 3000 mAh Lithium-polymer battery. Electronic equipment and wiring are hosted into the hollow arms and on several carbon fiber platforms in the waterproof fuselage. Four 35A high-torque motors are supported at the far end of each arm with 10 × 4.7 inch propellers. Energy dissipation during landing is accomplished by four pivoting legs that, through the use of shock absorbers, prevent the impact energy from affecting the frame thus causing significant damage. The data capturing system consists of a GoPro Hero3 camera and in-house built camera gimbal and shock absorber damping device. The camera gimbal, hosted below the vehicle fuselage, is engineered to maintain the orthogonality of the camera axis with respect to the water surface by

  17. A model-based framework for the quality assessment of surface albedo in situ measurement protocols

    Science.gov (United States)

    Adams, Jennifer; Gobron, Nadine; Widlowski, Jean-Luc; Mio, Corrado

    2016-09-01

    Satellite-based retrievals of land surface albedo are essential for climate and environmental modelling communities. To be of use, satellite-retrievals are required to comply to given accuracy requirements, mainly achieved through comparison with in situ measurements. Differences between in situ and satellite-based retrievals depend on their actual difference and their associated uncertainties. It is essential that these uncertainties can be computed to properly understand the differences between satellite-based and in situ measurements of albedo, however quantifying the individual contributions of uncertainty is difficult. This study introduces a model-based framework for assessing the quality of in situ albedo measurements. A 3D Monte Carlo Ray Tracing (MCRT) radiative transfer model is used to simulate field measurements of surface albedo, and is able to identify and quantify potential sources of error in the field measurement. Compliance with the World Meteorological Organisation (WMO) requirement for 3% accuracy is tested. 8 scenarios were investigated, covering a range of ecosystem types and canopy structures, seasons, illumination angles and tree heights. Results indicate that height of measurement above the canopy is the controlling factor in accuracy, with each canopy scenario reaching the WMO requirement at different heights. Increasing canopy heterogeneity and tree height noticeably reduces the accuracy, whereas changing seasonality from summer to winter in a deciduous forest increases accuracy. For canopies with a row structure, illumination angle can significantly impact accuracy as a result of shadowing effects. Tests were made on the potential use of multiple in situ measurements, indicating considerably increased accuracy if two or more in situ measurements can be made.

  18. Extension of MF radar tidal measurements to E-region heights (95-125 km: Saskatoon (52°N, 107°W, Canada

    Directory of Open Access Journals (Sweden)

    S. P. Namboothiri

    Full Text Available Efforts have been made to extend the MF radar tidal profiles to E-region heights. The totally reflected MF radar echoes from E-region heights during daytime are known to be group-retarded and the corresponding wind and tidal data will have associated height discrepancies. The estimation of the E-region real heights (Namboothiri et al., 1993, and the elimination of the data for which the group retardation is significant, are selected as the basic criteria to extend the tidal profiles to 100-125 km. The analysis of the quiet (Ap<19 days of the winter and summer seasons of 1988/89 shows that the tidal propagation continues to higher altitudes with some changes in their pattern, e.g. longer wavelengths, compared to that in the lower altitudes. Comparison with the model profiles shows some resemblance and some disagreements. The reliability of the MF radar tidal measurements of E-region heights and the propagation of tides in this region have been discussed in the light of existing theories and other experimental observations. It is concluded that, based on the initial studies with UHF and MF systems and within the limits of the available theories, the information on tides presented here for the 100-125 km region using the MF radar observations is useful. Suggestions for future work in this direction are also given.

  19. Comparison of BMI Derived from Parent-Reported Height and Weight with Measured Values: Results from the German KiGGS Study

    Directory of Open Access Journals (Sweden)

    Angelika Schaffrath Rosario

    2012-02-01

    Full Text Available The use of parent-reported height and weight is a cost-efficient instrument to assess the prevalence of children’s weight status in large-scale surveys. This study aimed to examine the accuracy of BMI derived from parent-reported height and weight and to identify potential predictors of the validity of BMI derived from parent-reported data. A subsample of children aged 2–17 years (n = 9,187 was taken from the 2003–2006 cross-sectional German KiGGS study. Parent-reported and measured height and weight were collected and BMI was calculated. Besides descriptive analysis, linear regression models with BMI difference and logistic regression models with weight status misclassification as dependent variables were calculated. Height differences varied by gender and were generally small. Weight and BMI were under-reported in all age groups, the under-reporting getting stronger with increasing age. Overall, the proportion for overweight and obesity based on parental and measured reports differed slightly. In the youngest age group, the proportion of overweight children was overestimated, while it was underestimated for older children and adolescents. Main predictors of the difference between parent reported and measured values were age, gender, weight status and parents’ perception of the child’s weight. In summary, the exclusive use of uncorrected parental reports for assessment of prevalence rates of weight status is not recommended.

  20. Comparison of self-reported and directly measured weight and height among women of reproductive age: a systematic review and meta-analysis.

    Science.gov (United States)

    Seijo, Mariana; Minckas, Nicole; Cormick, Gabriela; Comandé, Daniel; Ciapponi, Agustín; BelizÁn, José M

    2018-04-01

    The use of self-report as a strategy for collecting data on women's weight and height is widespread in both clinical practice and epidemiological studies. This study aimed to compare self-reported and directly measured weight and height among women of reproductive age. In July 2015 we searched MEDLINE, EMBASE, COCHRANE, CINHAL, LILACS and gray literature. We included women of reproductive age (12-49 years old) independently of their weight or height at the time of the study. Women with any condition that implies regular tracking of their weight (for example, eating disorder) were excluded. Two reviewers independently selected, extracted and assessed the risk of bias of the studies. We used REVMAN 5.3 to perform the meta-analysis. Heterogeneity was assessed using the I 2 statistic. Following eligibility assessment, 21 studies of 18 749 women met the inclusion criteria. The results of the meta-analysis showed an underestimation of weight by -0.94 kg (95% CI -1.17 to -0.71 kg; p self-reported vs. directly measured values. This review shows that self-reported weight and height of women of reproductive age differs slightly from direct measures. We consider that the magnitude at which self-reported data over- or underestimates the real value, is negligible regarding clinical and research use. © 2018 Nordic Federation of Societies of Obstetrics and Gynecology.

  1. UAV BASED BRDF-MEASUREMENTS OF AGRICULTURAL SURFACES WITH PFIFFIKUS

    Directory of Open Access Journals (Sweden)

    G. J. Grenzdörffer

    2012-09-01

    Full Text Available BRDF is a common problem in remote sensing and also in oblique photogrammetry. Common approaches of BRDF-measurement with a field goniometer are costly and rather cumbersome. UAVs may offer an interesting alternative by using a special flight pattern of oblique and converging images. The main part of this paper is the description of a photogrammetric workflow in order to determine the anisotropic reflection properties of a given surface. Due to the relatively low flying heights standard procedures from close range photogrammetry were adopted for outdoor usage. The photogrammetric processing delivered automatic and highly accurate orientation information with the aid of coded targets. The interior orientation of the consumer grade camera is more or less stable. The radiometrically corrected oblique images are converted into ortho photos. The azimuth and elevation angle of every point may then be computed. The calculated anisotropy of a winter wheat plot is shown. A system four diagonally-looking cameras (Four Vision and an additional nadir looking camera is under development. The multi camera system especially designed for a Micro- UAV with a payload of min 1 kg. The system is composed of five industrial digital frame cameras (1.3 Mpix CCD-chips, 15 fp/s with fixed lenses. Also special problems with the construction of a light weight housing of the multi camera solution are covered in the paper.

  2. Utilizing the NASA and NOAA Joint Ocean Surface Topography Mission to Assess Patterns and Trends in Sea-Surface Height in the U.S. Affiliated Pacific Islands

    Science.gov (United States)

    Fitzgerald, S. S.; Walker, K. A.; Courtright, A. B.; Young, I. J.

    2017-12-01

    The United States Affiliated Pacific Islands (USAPI) are home to a population of low-lying coral atolls which are extremely vulnerable to sea level rise. Coastal infrastructure like groundwater reservoirs, harbor operations, and sewage systems, as well as natural coastal features such as reefs and beach ecosystems, are most vulnerable during inundation events. These Pacific Islanders face increasing hazards as coastal flooding infiltrates freshwater resources and may even lead to displacement. The two main components of inundation include tidal fluctuations and sea level anomalies; however, low-lying atolls are also vulnerable to the additional influence of waves. This study created a climatology of significant wave height in the Republic of the Marshall Islands (RMI), and incorporated this dataset with tides and sea level anomalies to create a novel approach to assessing inundation flood risk in the RMI. The risk metric was applied to the RMI as a study site with the goal of assessing wider-scale applicability across the rest of the USAPI. The inclusion of wave height and wave direction as a crucial component of the risk metric will better inform USAPI coastal-managers for future inundation events and disaster preparedness. In addition to the risk metric, a wave-rose atlas was created for decision-makers in the RMI. This study highlights the often-overlooked region of the Pacific and demonstrates the application of the risk metric to specific examples in the RMI.

  3. Measurements of dry-deposition rates on various earth surfaces by 212Pb

    International Nuclear Information System (INIS)

    Osaki, S.; Sugihara, S.; Maeda, Y.

    2004-01-01

    Dry deposition rates of 212 Pb on a coniferous forest (Japanese cedar) and a broad-leaf forest (Pasania edulis) have been measured. Those on various kinds of grass fields, various states on artificial surface such as water, paper, and standing paper have been also measured. The dry deposition rates depend on the characteristics of depositing particles and the conditions of deposited surfaces. Dry deposition rates on the forest of Japanese cedar are highest because of the complex and adhesive surface of the leaves. Those on various grass fields are roughly depend on the logarithm of the height of their grasses. The total deposition rates of 7 Be do not depend on the densities or heights of the grasses. 7 Be may be not kept on their leaves or surface soil for a long time. The dry deposition rates of on artificial surface, e.g. paper and water surfaces make clear the mechanism on dry deposition, and suggest that more chances of collision and more adhesive of the surface are important for the dry deposition. About 90% of all deposition on the artificial paper grass was attached on the standing paper. On water surface, 60% of the rate of paper grass was attached, but only about 20% were attached on a dry paper plate. The aerosol particles are deposited by collision with the surface, therefore the deposition velocity depends on the chance of collision and the characteristics of the surface. Therefore the dry deposition rates on forests are larger and those of coniferous forest are largest. (author)

  4. Study on dynamic deformation synchronized measurement technology of double-layer liquid surfaces

    Science.gov (United States)

    Tang, Huiying; Dong, Huimin; Liu, Zhanwei

    2017-11-01

    Accurate measurement of the dynamic deformation of double-layer liquid surfaces plays an important role in many fields, such as fluid mechanics, biomechanics, petrochemical industry and aerospace engineering. It is difficult to measure dynamic deformation of double-layer liquid surfaces synchronously for traditional methods. In this paper, a novel and effective method for full-field static and dynamic deformation measurement of double-layer liquid surfaces has been developed, that is wavefront distortion of double-wavelength transmission light with geometric phase analysis (GPA) method. Double wavelength lattice patterns used here are produced by two techniques, one is by double wavelength laser, and the other is by liquid crystal display (LCD). The techniques combine the characteristics such as high transparency, low reflectivity and fluidity of liquid. Two color lattice patterns produced by laser and LCD were adjusted at a certain angle through the tested double-layer liquid surfaces simultaneously. On the basis of the refractive indexes difference of two transmitted lights, the double-layer liquid surfaces were decoupled with GPA method. Combined with the derived relationship between phase variation of transmission-lattice patterns and out-of plane heights of two surfaces, as well as considering the height curves of the liquid level, the double-layer liquid surfaces can be reconstructed successfully. Compared with the traditional measurement method, the developed method not only has the common advantages of the optical measurement methods, such as high-precision, full-field and non-contact, but also simple, low cost and easy to set up.

  5. [Measuring microhardness of laser exposed tooth surface].

    Science.gov (United States)

    Florin, R; Herrmann, C; Bernhardt, W

    1990-02-01

    In principle it is possible to homogenize the enamel surface by melting structural elements with the continuous wave CO2 laser. Using the precision instrument NEOPHOT 2 (Carl Zeiss JENA) the microhardness of extracted laserexposed premolares were tested so as to clarify the functional strain capasity and the mechanical characteristics of laserexposed regions of enamel surfaces. The proven higher hardness in the centre of the laserinduced fusing zones (in comparison with adjacent enamel) objectify an attainable refining of the enamel surface that probably causes an increase in the caries-preventive resistance.

  6. Surface and Flow Field Measurements on the FAITH Hill Model

    Science.gov (United States)

    Bell, James H.; Heineck, James T.; Zilliac, Gregory; Mehta, Rabindra D.; Long, Kurtis R.

    2012-01-01

    A series of experimental tests, using both qualitative and quantitative techniques, were conducted to characterize both surface and off-surface flow characteristics of an axisymmetric, modified-cosine-shaped, wall-mounted hill named "FAITH" (Fundamental Aero Investigates The Hill). Two separate models were employed: a 6" high, 18" base diameter machined aluminum model that was used for wind tunnel tests and a smaller scale (2" high, 6" base diameter) sintered nylon version that was used in the water channel facility. Wind tunnel and water channel tests were conducted at mean test section speeds of 165 fps (Reynolds Number based on height = 500,000) and 0.1 fps (Reynolds Number of 1000), respectively. The ratio of model height to boundary later height was approximately 3 for both tests. Qualitative techniques that were employed to characterize the complex flow included surface oil flow visualization for the wind tunnel tests, and dye injection for the water channel tests. Quantitative techniques that were employed to characterize the flow included Cobra Probe to determine point-wise steady and unsteady 3D velocities, Particle Image Velocimetry (PIV) to determine 3D velocities and turbulence statistics along specified planes, Pressure Sensitive Paint (PSP) to determine mean surface pressures, and Fringe Imaging Skin Friction (FISF) to determine surface skin friction (magnitude and direction). This initial report summarizes the experimental set-up, techniques used, data acquired and describes some details of the dataset that is being constructed for use by other researchers, especially the CFD community. Subsequent reports will discuss the data and their interpretation in more detail

  7. Aerosol height retrieval from satellite visible measurements: application to OMI 477 nm O2-O2 spectral band, based on Neural Networks

    Science.gov (United States)

    Chimot, Julien; Veefkind, Pepijn; Vlemmix, Tim; Levelt, Pieternel

    2017-04-01

    The ability to monitor air quality and climate from UltraViolet-Visible (UV-Vis) satellite spectral measurements relies on accurate trace gas (e.g. NO2, SO2, HCHO, O3) columns combined with aerosol properties and vertical distribution. In the absence of clouds, the most important error source on the observations of trace gases in the troposphere are aerosols, since their scattering and absorbing properties modify the average light path followed by the detected photons. Large impacts due to their vertical distribution uncertainties remain when retrieving vertical column densities of trace gases from UV-Vis air quality space-borne sensors [Krotkov et al., 2008; Boersma et al., 2011; Barkley et al., 2012; Hewson et al., 2015; Castellanos et al., 2015; Chimot et al., 2016a]. Aerosols and trace gases share, over urban and industrialized areas, similar anthropogenic sources, and their concentrations, as shown by the satellite observations, often present significant correlations [Veefkind et al., 2011]. We have recently developed a Multilayer Perceptron Neural Network (NN) algorithm to retrieve Aerosol Layer Height (ALH) from the OMI 477 nm O2-O2 absorption band [Chimot et al., 2016b]. This algorithm represents aerosols in the troposphere as a single scattering layer defined by its mean altitude and homogeneous optical properties. This algorithm enables the link between the OMI O2-O2 slant column density derived from the 477 nm spectral measurements and the aerosol layer altitude. A prior information about the Aerosol Optical Thickness (AOT) is needed to distinguish the effects due to the amount of fine particles and their altitude. Therefore, the ALH retrieval strongly benefits from a synergy between OMI 477 nm O2-O2 spectral measurements and MODIS AOT product. Aerosol layer heights are currently retrieved with an uncertainty in the range of 260-800 m for scenes with AOT larger than 1. Improvement of these retrievals can be expected by improving assumptions on the

  8. Surface texturing of crystalline silicon and effective area measurement

    Science.gov (United States)

    Sun, Tietun; Chen, Dong; Chui, Rongqiang

    2000-11-01

    In this paper, the surface area of solar cell is determined by the capacitance measurements of MOS structure. The texture etching technology can be controlled according to the change of silicon surface area, furthermore, the textured silicon surface and interface characteristic of solar cell can be studied by measuring the relationship of capacitance and voltage for MOS structure.

  9. Full-field transmission-type angle-deviation optical microscope with reflectivity-height transformation.

    Science.gov (United States)

    Chiu, Ming-Hung; Tan, Chen-Tai; Tsai, Ming-Hung; Yang, Ya-Hsin

    2015-10-01

    This full-field transmission-type three-dimensional (3D) optical microscope is constructed based on the angle deviation method (ADM) and the algorithm of reflectivity-height transformation (RHT). The surface height is proportional to the deviation angle of light passing through the object. The angle deviation and surface height can be measured based on the reflectivity closed to the critical angle using a parallelogram prism and two CCDs.

  10. A non-parametric conditional bivariate reference region with an application to height/weight measurements on normal girls

    DEFF Research Database (Denmark)

    Petersen, Jørgen Holm

    2009-01-01

    A conceptually simple two-dimensional conditional reference curve is described. The curve gives a decision basis for determining whether a bivariate response from an individual is "normal" or "abnormal" when taking into account that a third (conditioning) variable may influence the bivariate...... response. The reference curve is not only characterized analytically but also by geometric properties that are easily communicated to medical doctors - the users of such curves. The reference curve estimator is completely non-parametric, so no distributional assumptions are needed about the two......-dimensional response. An example that will serve to motivate and illustrate the reference is the study of the height/weight distribution of 7-8-year-old Danish school girls born in 1930, 1950, or 1970....

  11. A morphometric study of measurements of heart in adults and its relation with age and height of the individual: A post-mortem study

    Directory of Open Access Journals (Sweden)

    Chandni Gupta

    2014-01-01

    Full Text Available Objective: Reconstructive and replacement operations of diseased cardiac valves are commonly practiced these days. It may be noted that the choice of proper reconstructive intervention and prosthetic replacement might require the normal morphometric measurements of heart in relation with general body parameters, like age and height. So, this study was undertaken to measure various measurements of heart and its relation with age and height of the individual. Materials and Methods: Sixty five normal post-mortem hearts of adults were taken from the mortuary of Department of Forensic Medicine. Age of the individual was noted. Length of the deceased was measured with a measuring tape from the level of vertex to the outer border of heel. Length (from apex to base, breadth (at broadest diameter and thickness of the heart were measured with slide callipers. Weight was measured with weighing machine. Results: The mean length, breadth, thickness of heart in males and females are 11.25, 8.78, 3.97 cm and 10.60, 8.31, 3.63 cm. The mean weight of heart in males and females was 323 and 276 gms. There was significant correlation with weight of individual and weight of heart in males. There was significant correlation with age of individual and length of heart in females. Conclusion: This study will be helpful for cardiothoracic surgeons while doing surgery on hearts.

  12. Surface topography measurements over the 1 meter to 10 micrometer spatial period bandwidth

    International Nuclear Information System (INIS)

    Takacs, P.Z.; Furenlid, K.; DeBiasse, R.A.; Church, E.L.

    1989-09-01

    A recently-developed long-trace surface profiling instrument (LTP) is now in operation in our laboratory measuring surface profiles on grazing incidence aspheres and also conventional optical surface. The LTP characterizes surface height profiles in a non-contact manner over spatial periods ranging from 1 meter (the maximum scan length) to 2 mm (the Nyquist period for 1 mm sampling period) and complements the range of our WYKO NCP-1000 2.5X surface roughness profiler (5 mm to 9.8 μm). Using these two instruments, we can fully characterize both figure and finish of an optical surface in the same way that we normally characterize surface finish, e.g., by means of the power spectral density function in the spatial frequency domain. A great deal of information about the distribution of figure errors over various spatial frequency ranges is available from this data, which is useful for process control and predicting performance at the desired wavelength and incidence angle. In addition, the LTP is able to measure the absolute radius of curvature on long-radius optics with high precision and accuracy. Angular errors in the optical head are measured in real time by an electronic autocollimator as the head traverses the linear air bearing slide. Measurements of kilometer radius optics can be made very quickly and the data analyzed in a format that is very easy to understand. 17 refs., 10 figs

  13. Measuring the sizes of nanospheres on a rough surface by using atomic force microscopy and a curvature-reconstruction method

    International Nuclear Information System (INIS)

    Oikawa, Koudai; Kim, Hyonchol; Watanabe, Naoya; Shigeno, Masatsugu; Shirakawabe, Yoshiharu; Yasuda, Kenji

    2007-01-01

    One of the advantages of atomic force microscopy (AFM) is that it can accurately measure the heights of targets on flat substrates. It is difficult, however, to determine the shape of nanoparticles on rough surfaces. We therefore propose a curvature-reconstruction method that estimates the sizes of particles by fitting sphere curvatures acquired from raw AFM data. We evaluated this fitting estimation using 15-, 30-, and 50-nm gold nanoparticles on mica and confirmed that particle sizes could be estimated within 5% from 20% of their curvature measured using a carbon nanotube (CNT) tip. We also estimated the sizes of nanoparticles on the rough surface of dried cells and found we also can estimate the size of those particles within 5%, which is difficult when we only used the height information. The results indicate the size of nanoparticles even on rough surfaces can be measured by using our method and a CNT tip

  14. High speed machined surface roughness measurement ...

    African Journals Online (AJOL)

    Surface roughness monitoring techniques using non-contact methods based on computer vision technology are becoming popular and cost effective. An evolvable hardware configuration using reconfigurable Xilinx Virtex FPGA xcv1000 architecture with capability to compensate for poor illumination environment is ...

  15. Error sources in the retrieval of aerosol information over bright surfaces from satellite measurements in the oxygen A band

    Science.gov (United States)

    Nanda, Swadhin; de Graaf, Martin; Sneep, Maarten; de Haan, Johan F.; Stammes, Piet; Sanders, Abram F. J.; Tuinder, Olaf; Pepijn Veefkind, J.; Levelt, Pieternel F.

    2018-01-01

    Retrieving aerosol optical thickness and aerosol layer height over a bright surface from measured top-of-atmosphere reflectance spectrum in the oxygen A band is known to be challenging, often resulting in large errors. In certain atmospheric conditions and viewing geometries, a loss of sensitivity to aerosol optical thickness has been reported in the literature. This loss of sensitivity has been attributed to a phenomenon known as critical surface albedo regime, which is a range of surface albedos for which the top-of-atmosphere reflectance has minimal sensitivity to aerosol optical thickness. This paper extends the concept of critical surface albedo for aerosol layer height retrievals in the oxygen A band, and discusses its implications. The underlying physics are introduced by analysing the top-of-atmosphere reflectance spectrum as a sum of atmospheric path contribution and surface contribution, obtained using a radiative transfer model. Furthermore, error analysis of an aerosol layer height retrieval algorithm is conducted over dark and bright surfaces to show the dependence on surface reflectance. The analysis shows that the derivative with respect to aerosol layer height of the atmospheric path contribution to the top-of-atmosphere reflectance is opposite in sign to that of the surface contribution - an increase in surface brightness results in a decrease in information content. In the case of aerosol optical thickness, these derivatives are anti-correlated, leading to large retrieval errors in high surface albedo regimes. The consequence of this anti-correlation is demonstrated with measured spectra in the oxygen A band from the GOME-2 instrument on board the Metop-A satellite over the 2010 Russian wildfires incident.

  16. [Particle numbers in classified sizes of roadside dust caused by studded tires in the air at different heights from the pavement surface].

    Science.gov (United States)

    Sato, T; Niioka, T; Kurasaki, M; Kojima, Y

    1996-07-01

    Increased use of motor vehicles has produced various risks to human health due to air pollution by noxious gases, heavy metals and roadside dust. Since the late 1970s, the wide spread use of studded tires for cars has caused pavement wear, resulting in not only economic losses, but also roadside air pollution in cold and snowy regions in Japan. The most serious environmental problem in Sapporo, a city with heavy snowfall, in the 1980s, was roadside dust derived from studded tires. The inhabitants suffered from this dust in the early winter and in the early spring when the streets were not covered with snow. To investigate the influence of such roadside dust upon human health, particle numbers in classified sizes of roadside dust were counted after the roadside dust in the air was collected with a device we constructed at 30, 60, 90, 120, 150, and 180 cm above the pavement surface. The results indicated that the concentration of roadside dust in the air did not greatly vary according to the height from the pavement surface. The results also suggested that xenogranuloma, reported in lungs of stray dogs, under roadside dust-pollution conditions such as those examined here, may occur in humans in the future.

  17. The prediction of BRDFs from surface profile measurements

    International Nuclear Information System (INIS)

    Church, E.L.; Takacs, P.Z.; Leonard, T.A.

    1989-01-01

    This paper discusses methods of predicting the BRDF of smooth surfaces from profile measurements of their surface finish. The conversion of optical profile data to the BRDF at the same wavelength is essentially independent of scattering models, while the conversion of mechanical measurements, and wavelength scaling in general, are model dependent. Procedures are illustrated for several surfaces, including two from the recent HeNe BRDF round robin, and results are compared with measured data. Reasonable agreement is found except for surfaces which involve significant scattering from isolated surface defects which are poorly sampled in the profile data

  18. Rivited panel surface measurement using photogrammetry

    Science.gov (United States)

    Merrick, W. D.; Lobb, V. B.; Lansing, F. L.; Stoller, F. W.

    1986-01-01

    Two riveted antenna panels on rings number 3 and 9 were removed from the 34m antenna at DSS-15, fixed in the leveled position and the surface was photographed indoors. The results from this pilot photogrammetric demonstration and diagnostics of panel surface contours, are presented. The photogrammetric network for each panel incorporated eight photographs, two from each of four camera stations and observed over 200 targets. The accuracy (1 sigma) of the XYZ coordinates for the error ellipsoids was + or - 0.013 mm (0.0005 inch). This level of precision relative to the object size corresponds roughly to 1 part in 250,000 which is superior to conventional dial sweep-arm template techniques by at least a factor of 4.

  19. Bringing satellite winds to hub-height

    DEFF Research Database (Denmark)

    Badger, Merete; Pena Diaz, Alfredo; Bredesen, Rolv Erlend

    2012-01-01

    Satellite observations of the ocean surface can provide detailed information about the spatial wind variability over large areas. This is very valuable for the mapping of wind resources offshore where other measurements are costly and sparse. Satellite sensors operating at microwave frequencies...... measure the amount of radar backscatter from the sea surface, which is a function of the instant wind speed, wind direction, and satellite viewing geometry. A major limitation related to wind retrievals from satellite observations is that existing empirical model functions relate the radar backscatter...... to wind speed at the height 10 m only. The extrapolation of satellite wind fields to higher heights, which are more relevant for wind energy, remains a challenge which cannot be addressed by means of satellite data alone. As part of the EU-NORSEWInD project (2008-12), a hybrid method has been developed...

  20. Surface Temperature Measurement Using Hematite Coating

    Science.gov (United States)

    Bencic, Timothy J. (Inventor)

    2015-01-01

    Systems and methods that are capable of measuring temperature via spectrophotometry principles are discussed herein. These systems and methods are based on the temperature dependence of the reflection spectrum of hematite. Light reflected from these sensors can be measured to determine a temperature, based on changes in the reflection spectrum discussed herein.

  1. Sri Lanka, Colored Height

    Science.gov (United States)

    2005-01-01

    Jaffna peninsula. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C. Location: 8.0 degrees North latitude, 80.7 degrees East longitude Orientation: North toward the top, Mercator projection Size: 275.6 by 482.4 kilometers (165.4 by 299.0 miles) Image Data: shaded and colored SRTM elevation model Date Acquired: February 2000

  2. Heritability of adult body height

    DEFF Research Database (Denmark)

    Silventoinen, Karri; Sammalisto, Sampo; Perola, Markus

    2003-01-01

    A major component of variation in body height is due to genetic differences, but environmental factors have a substantial contributory effect. In this study we aimed to analyse whether the genetic architecture of body height varies between affluent western societies. We analysed twin data from...... eight countries comprising 30,111 complete twin pairs by using the univariate genetic model of the Mx statistical package. Body height and zygosity were self-reported in seven populations and measured directly in one population. We found that there was substantial variation in mean body height between...... countries; body height was least in Italy (177 cm in men and 163 cm in women) and greatest in the Netherlands (184 cm and 171 cm, respectively). In men there was no corresponding variation in heritability of body height, heritability estimates ranging from 0.87 to 0.93 in populations under an additive genes...

  3. The Surface Water and Ocean Topography Satellite Mission - An Assessment of Swath Altimetry Measurements of River Hydrodynamics

    Science.gov (United States)

    Wilson, Matthew D.; Durand, Michael; Alsdorf, Douglas; Chul-Jung, Hahn; Andreadis, Konstantinos M.; Lee, Hyongki

    2012-01-01

    The Surface Water and Ocean Topography (SWOT) satellite mission, scheduled for launch in 2020 with development commencing in 2015, will provide a step-change improvement in the measurement of terrestrial surface water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water surface elevations, which will allow for the estimation of river and floodplain flows via the water surface slope. In this paper, we characterize the measurements which may be obtained from SWOT and illustrate how they may be used to derive estimates of river discharge. In particular, we show (i) the spatia-temporal sampling scheme of SWOT, (ii) the errors which maybe expected in swath altimetry measurements of the terrestrial surface water, and (iii) the impacts such errors may have on estimates of water surface slope and river discharge, We illustrate this through a "virtual mission" study for a approximately 300 km reach of the central Amazon river, using a hydraulic model to provide water surface elevations according to the SWOT spatia-temporal sampling scheme (orbit with 78 degree inclination, 22 day repeat and 140 km swath width) to which errors were added based on a two-dimension height error spectrum derived from the SWOT design requirements. Water surface elevation measurements for the Amazon mainstem as may be observed by SWOT were thereby obtained. Using these measurements, estimates of river slope and discharge were derived and compared to those which may be obtained without error, and those obtained directly from the hydraulic model. It was found that discharge can be reproduced highly accurately from the water height, without knowledge of the detailed channel bathymetry using a modified Manning's equation, if friction, depth, width and slope are known. Increasing reach length was found to be an effective method to reduce systematic height error in SWOT measurements.

  4. Unified height systems after GOCE

    Science.gov (United States)

    Rummel, Reiner; Gruber, Thomas; Sideris, Michael; Rangelova, Elena; Woodworth, Phil; Hughes, Chris; Ihde, Johannes; Liebsch, Gunter; Rülke, Axel; Gerlach, Christian; Haagmans, Roger

    2015-04-01

    adopted standards and methodology. This procedure will allow bringing all included stations into one and the same height datum. In sparsely surveyed regions of our planet the uncertainty of height off-sets may be at the level of 20 to 40cm (with extreme values up to 1m). In coastal regions, applying ocean levelling, these numbers may be improved. Ocean levelling is the combination of a "best" ocean topography model with either an altimetric mean sea surface or, at tide gauges, mean sea level as derived from a combination of tide gauge recording and GNSS positioning. The classical geoid definition and realization is operational at the level of a decimeter but poses significant theoretical and operational challenges at the sub-decimetre level.

  5. Radioactivity Measurements on Glazed Ceramic Surfaces

    OpenAIRE

    Hobbs, Thomas G.

    2000-01-01

    A variety of commonly available household and industrial ceramic items and some specialty glass materials were assayed by alpha pulse counting and ion chamber voltage measurements for radioactivity concentrations. Identification of radionuclides in some of the items was performed by gamma spectroscopy. The samples included tableware, construction tiles and decorative tiles, figurines, and other products with a clay based composition. The concentrations of radioactivity ranged from near backgr...

  6. Piezotransistive GaN microcantilevers based surface work function measurements

    Science.gov (United States)

    Bayram, Ferhat; Khan, Digangana; Li, Hongmei; Maksudul Hossain, Md.; Koley, Goutam

    2018-04-01

    Surface work function (SWF) measurements using a piezotransistive III–nitride cantilever has been demonstrated on multiple surfaces. The minimum detectable surface potential change of 10 mV was achieved with a signal to noise ratio of 3. This method was applied to determine the surface potential changes due to exposure of 5 ppm NO2 in graphene and In2O3 thin film, simultaneously with conductivity changes. The potentiometric measurements yielded 100 and 80 mV potential changes in SWFs of graphene and In2O3 respectively, which matches very well with experimental data published earlier indicating the efficacy of this readily miniaturizable measurement technique.

  7. Real-time sensing of enteropathogenic E. coli-induced effects on epithelial host cell height, cell-substrate interactions, and endocytic processes by infrared surface plasmon spectroscopy.

    Directory of Open Access Journals (Sweden)

    Victor Yashunsky

    Full Text Available Enteropathogenic Escherichia coli (EPEC is an important, generally non-invasive, bacterial pathogen that causes diarrhea in humans. The microbe infects mainly the enterocytes of the small intestine. Here we have applied our newly developed infrared surface plasmon resonance (IR-SPR spectroscopy approach to study how EPEC infection affects epithelial host cells. The IR-SPR experiments showed that EPEC infection results in a robust reduction in the refractive index of the infected cells. Assisted by confocal and total internal reflection microscopy, we discovered that the microbe dilates the intercellular gaps and induces the appearance of fluid-phase-filled pinocytic vesicles in the lower basolateral regions of the host epithelial cells. Partial cell detachment from the underlying substratum was also observed. Finally, the waveguide mode observed by our IR-SPR analyses showed that EPEC infection decreases the host cell's height to some extent. Together, these observations reveal novel impacts of the pathogen on the host cell architecture and endocytic functions. We suggest that these changes may induce the infiltration of a watery environment into the host cell, and potentially lead to failure of the epithelium barrier functions. Our findings also indicate the great potential of the label-free IR-SPR approach to study the dynamics of host-pathogen interactions with high spatiotemporal sensitivity.

  8. Comparative analyses of measured evapotranspiration for various land surfaces

    Science.gov (United States)

    Suat Irmak

    2016-01-01

    There is a significant lack of continuously measured ET data for multiple land surfaces in the same area to be able to make comparisons of water use rates of different agroecosystems. This research presentation will provide continuous evapotranspiration and other surface energy balance variables measured above multiple land use and management practices.

  9. Specific surface as a measure of burial diagenesis of chalk

    DEFF Research Database (Denmark)

    Borre, Mai Kirstine; Lind, Ida; Mortensen, Jeanette

    1997-01-01

    the relative importance of the three processes, simple models have been established to illustrate changes in pore space, particle size and -shape and the resulting trends in the specific surface. Specific surface and porosity of the samples were measured using image analysis on electron micrographs of polished...... sections. Using these simple models, trends in the measured specific surface can be interpred throughout the majority of the geological sequence....

  10. On the Extreme Wave Height Analysis

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1994-01-01

    The determination of the design wave height is usually based on the statistical analysis of long-term extreme wave height measurements. After an introduction to the procedure of the extreme wave height analysis, the paper presents new development concerning various aspects of the extreme wave hei...... height analysis. Finally, the paper gives a practical example based on a data set of the hindcasted wave heights for a deep water location in the Mediterranean Sea....

  11. Development of material measures for performance verifying surface topography measuring instruments

    International Nuclear Information System (INIS)

    Leach, Richard; Giusca, Claudiu; Rickens, Kai; Riemer, Oltmann; Rubert, Paul

    2014-01-01

    The development of two irregular-geometry material measures for performance verifying surface topography measuring instruments is described. The material measures are designed to be used to performance verify tactile and optical areal surface topography measuring instruments. The manufacture of the material measures using diamond turning followed by nickel electroforming is described in detail. Measurement results are then obtained using a traceable stylus instrument and a commercial coherence scanning interferometer, and the results are shown to agree to within the measurement uncertainties. The material measures are now commercially available as part of a suite of material measures aimed at the calibration and performance verification of areal surface topography measuring instruments

  12. Proposed Lucas Heights tandem accelerator

    International Nuclear Information System (INIS)

    1985-01-01

    An 8 million volt tandem accelerator (LHTA - Lucas Heights Tandem Accelerator) is proposed to be installed at the Australian Atomic Energy Commission's Lucas Heights Research Laboratories. The new facility is expected to cost $6 million and will have applications such as ultrasensitive trace element analysis for management of groundwater resources, salinity in soil, soil erosion and Antarctic research. Applied physics applications include nuclear safeguards, energy sources, study of material surfaces, archaeology, archaeometry and occupational health

  13. Mapping ionospheric backscatter measured by the SuperDARN HF radars – Part 2: Assessing SuperDARN virtual height models

    Directory of Open Access Journals (Sweden)

    T. K. Yeoman

    2008-05-01

    Full Text Available The Super Dual Auroral Radar Network (SuperDARN network of HF coherent backscatter radars form a unique global diagnostic of large-scale ionospheric and magnetospheric dynamics in the Northern and Southern Hemispheres. Currently the ground projections of the HF radar returns are routinely determined by a simple rangefinding algorithm, which takes no account of the prevailing, or indeed the average, HF propagation conditions. This is in spite of the fact that both direct E- and F-region backscatter and 1½-hop E- and F-region backscatter are commonly used in geophysical interpretation of the data. In a companion paper, Chisham et al. (2008 have suggested a new virtual height model for SuperDARN, based on average measured propagation paths. Over shorter propagation paths the existing rangefinding algorithm is adequate, but mapping errors become significant for longer paths where the roundness of the Earth becomes important, and a correct assumption of virtual height becomes more difficult. The SuperDARN radar at Hankasalmi has a propagation path to high power HF ionospheric modification facilities at both Tromsø on a ½-hop path and SPEAR on a 1½-hop path. The SuperDARN radar at Þykkvibǽr has propagation paths to both facilities over 1½-hop paths. These paths provide an opportunity to quantitatively test the available SuperDARN virtual height models. It is also possible to use HF radar backscatter which has been artificially induced by the ionospheric heaters as an accurate calibration point for the Hankasalmi elevation angle of arrival data, providing a range correction algorithm for the SuperDARN radars which directly uses elevation angle. These developments enable the accurate mappings of the SuperDARN electric field measurements which are required for the growing number of multi-instrument studies of the Earth's ionosphere and magnetosphere.

  14. Surface-Based 3d measurements of aeolian bedforms on Mars

    Science.gov (United States)

    Balme, Matthew; Robson, Ellen; Barnes, Robert; Huber, Ben; Butcher, Frances; Fawdon, Peter; Gupta, Sanjeev; Paar, Gerhard

    2017-04-01

    The surface of Mars hosts many different types of aeolian bedforms, from small wind-ripples with cm-scale wavelength, through decametre-scale "Transverse Aeolian Ridges" (TARs), to km-scale dunes. To date, all mobile Mars surface-missions ('Rovers') have encountered aeolian bedforms of one kind or another. Aeolian deposits of loose, unconsolidated material provide hazards to Mars Rovers: sinkage into the aeolian material and enhanced slippage can prevent traction and forward progress, forcing the Rover to backtrack (e.g., MER Opportunity) and can even 'trap' the rover ending the mission (e.g., MER Spirit). Here, we present morphometry measurements of meter-scale ripple-like bedforms on Mars, as observed by the MER Opportunity Rover during its traverse across the Meridiani Planum region of Mars. The aim is to assess whether there is a relationship between bedforms parameters that can be measured from orbit such as length and width, and bedform height, which can only be reliably measured from orbit for larger features such as TARs. If such a relationship can be found, it might allow estimates of ripple-height to be made from remote sensing data alone. This could help understand the formation mechanism and provide a better characterization of the hazard presented by these features. For much of the first 30 km of the traverse, Opportunity travelled across flat plains with meter-scale, ripple-like aeolian bedforms ("plains ripples") superposed upon them. During the traverse, the Rover acquired stereo imaging data of its surroundings using both its scientific Pancam cameras system and the navigational Navcam system. Using these data, and newly developed Pro3D™ and PRoViP™ software from Joanneum Research, we obtained Digital Elevation Models of many areas along the traverse, allowing us to measure the heights, widths and lengths of aeolian bedforms. In addition, the same bedforms were digitized from orbital HiRISE image data (25 cm/pix resolution) in ArcGIS software

  15. Radioactivity Measurements on Glazed Ceramic Surfaces.

    Science.gov (United States)

    Hobbs, T G

    2000-01-01

    A variety of commonly available household and industrial ceramic items and some specialty glass materials were assayed by alpha pulse counting and ion chamber voltage measurements for radioactivity concentrations. Identification of radionuclides in some of the items was performed by gamma spectroscopy. The samples included tableware, construction tiles and decorative tiles, figurines, and other products with a clay based composition. The concentrations of radioactivity ranged from near background to about four orders of magnitude higher. Almost every nuclide identification test demonstrated some radioactivity content from one or more of the naturally occurring radionuclide series of thorium or uranium. The glazes seemed to contribute most of the activity, although a sample of unglazed pottery greenware showed some activity. Samples of glazing paints and samples of deliberately doped glass from the World War II era were included in the test, as was a section of foam filled poster board. A glass disc with known (232)Th radioactivity concentration was cast for use as a calibration source. The results from the two assay methods are compared, and a projection of sensitivity from larger electret ion chamber devices is presented.

  16. Using Correction Equations Based on Measured Height and Weight Weakens Associations between Obesity Based on Self-Reports and Chronic Diseases

    Directory of Open Access Journals (Sweden)

    Cynthia L. Murray

    2013-01-01

    Full Text Available Objective. Researchers have established a preponderance of height overestimation among men and weight underestimation among women in self-reported anthropometric data, which skews obesity prevalence data and obscures obesity-chronic disease relationships. The objective of this study was to reevaluate associations between obesity and chronic diseases using body mass index (BMI correction equations derived from measured data. Methods. Measured height and weight (MHW data were collected on a subsample of the 17,126 Atlantic Canadians who participated in the 2007-2008 Canadian Community Health Survey (CCHS. To obtain corrected BMI estimates for the 17,126 adults, correction equations were developed in the MHW subsample and multiple regression procedures were used to model BMI. To test obesity-chronic disease relationships, logistic regression models were utilized. Results. The correction procedure eliminated statistically significant relations (P<0.05 between obesity and chronic bronchitis and obesity and stroke. Also, correction attenuated many relationships between adiposity and chronic disease. For example, among obese adults, there was a 13%, 12%, and 7% reduction in the adjusted odds ratios for asthma, urinary incontinence, and cardiovascular disease, respectively. Conclusion. Further research is needed to fully understand how the usage of self-reported data alters our understanding of the relationships between overweight or obesity and chronic diseases.

  17. SGP Cloud and Land Surface Interaction Campaign (CLASIC): Measurement Platforms

    Energy Technology Data Exchange (ETDEWEB)

    MA Miller; R Avissar; LK Berg; SA Edgerton; ML Fischer; TJ Jackson; B. Kustas; PJ Lamb; G McFarquhar; Q Min; B Schmid; MS Torn; DD Tuner

    2007-06-01

    The Cloud and Land Surface Interaction Campaign (CLASIC) will be conducted from June 8 to June 30, 2007, at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. Data will be collected using eight aircraft equipped with a variety of specialized sensors, four specially instrumented surface sites, and two prototype surface radar systems. The architecture of CLASIC includes a high-altitude surveillance aircraft and enhanced vertical thermodynamic and wind profile measurements that will characterize the synoptic scale structure of the clouds and the land surface within the ACRF SGP site. Mesoscale and microscale structures will be sampled with a variety of aircraft, surface, and radar observations. An overview of the measurement platforms that will be used during the CLASIC are described in this report. The coordination of measurements, especially as it relates to aircraft flight plans, will be discussed in the CLASIC Implementation Plan.

  18. A Study on 3-Dimensional Surface Measurement using Confocal Principle

    International Nuclear Information System (INIS)

    Kang, Young June; Song, Dae Ho; You, Weon Jae

    2001-01-01

    In modern industry, the accuracy and the sulfate-finish requirements for machined parts have been becoming ever more stringent. In addition, the measurement and understanding of surface topography is rapidly attracting the attention of the physicist and chemist as well as the engineer. Optical measuring method is used in vibration measurement, crack and defect detection with the advent of opto-mechatronics, and it is expected to play an important role in surface topography. In this study, the principle of confocal microscope is described, and the advanced 3-D surface measuring system that has better performance than the traditional confocal microscope is developed. Suitable fixtures arc developed and integrated with the computer system for generating 3-D surface and form data. Software for data acquisition and analysis of various parameters in surface geometrical features has been developed

  19. Trends, interannual and seasonal variations of tropospheric CO, C2H6 and HCN columns measured from ground-based FTIR at Lauder and Arrival Heights

    Science.gov (United States)

    Zeng, G.; Wood, S. W.; Morgenstern, O.; Jones, N. B.; Robinson, J.; Smale, D.

    2012-02-01

    We analyse the carbon monoxide (CO), ethane (C2H6) and hydrogen cyanide (HCN) partial columns (from the ground to 12 km) derived from measurements by ground-based solar Fourier Transform Spectroscopy at Lauder, New Zealand (45° S, 170° E) and at Arrival Heights, Antarctica (78° S, 167° E) from 1997 to 2009. Significant negative trends are calculated for all species at both locations: CO (-0.90 ± 0.31% yr-1) and C2H6 (-3.10 ± 1.07% yr-1) at Arrival Heights and CO (-0.87 ± 0.30% yr-1), C2H6 (-2.70 ± 0.94% yr-1) and HCN (-0.93 ± 0.32% yr-1) at Lauder. The uncertainties reflect the 95% confidence limits. The dominant seasonal trends of CO and C2H6 at Lauder, and to a lesser degree at Arrival Heights, occur in austral spring when the correlations between CO and C2H6 and between CO and HCN maximize. Tropospheric columns of all three species are characterised by minima in March-June and maxima from August to November; this season is the southern-hemisphere tropical and sub-tropical biomass burning period. A tropospheric chemistry-climate model is used to simulate CO and C2H6 columns for the period of 1997-2009 using interannually varying biomass burning emissions; the model simulated tropospheric columns of CO and C2H6 compare well with the measured partial columns of both species. However, the model does not re-produce the significant negative trends of observed CO and C2H6 partial columns at both locations. Weak negative trends are calculated from model data. The model sensitivity calculations indicate that long-range transport of biomass burning emissions from Southern Africa and South America dominate the seasonal cycles of CO and C2H6 at both Lauder and Arrival Heights. Interannual variability of these compounds at both locations is largely triggered by variations in biomass burning emissions associated with large-scale El Nino Southern Oscillation and prolonged biomass burning events, e.g. the Australian bush fires.

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

    Directory of Open Access Journals (Sweden)

    W. Dierking

    2017-08-01

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

  1. ROUGHNESS ON WOOD SURFACES AND ROUGHNESS MEASUREMENT METHODS

    Directory of Open Access Journals (Sweden)

    İsmail Aydın

    2003-04-01

    Full Text Available Some visual characteristics of wood such as color, pattern and texture determine the quality of manufactured products. Surface properties of wood material are important both in production and marketing after production. Initial studies related to the roughness of wood surface were begun in early 1950’s. However, no general agreed standardization can not have been developed for wood surfaces. Surface roughness of wood is function of the production process, product type and the natural anatomical properties of wood. Contact and non-contact tracing methods are used to measure of wood surface roughness. Surface roughness also affects the gluability and wettability of wood surfaces. The success in finishing also depends on the surface roughness of wood.

  2. Inferring hydroxyl layer peak heights from ground-based measurements of OH(6-2 band integrated emission rate at Longyearbyen (78° N, 16° E

    Directory of Open Access Journals (Sweden)

    F. J. Mulligan

    2009-11-01

    Full Text Available Measurements of hydroxyl nightglow emissions over Longyearbyen (78° N, 16° E recorded simultaneously by the SABER instrument onboard the TIMED satellite and a ground-based Ebert-Fastie spectrometer have been used to derive an empirical formula for the height of the OH layer as a function of the integrated emission rate (IER. Altitude profiles of the OH volume emission rate (VER derived from SABER observations over a period of more than six years provided a relation between the height of the OH layer peak and the integrated emission rate following the procedure described by Liu and Shepherd (2006. An extended period of overlap of SABER and ground-based spectrometer measurements of OH(6-2 IER during the 2003–2004 winter season allowed us to express ground-based IER values in terms of their satellite equivalents. The combination of these two formulae provided a method for inferring an altitude of the OH emission layer over Longyearbyen from ground-based measurements alone. Such a method is required when SABER is in a southward looking yaw cycle. In the SABER data for the period 2002–2008, the peak altitude of the OH layer ranged from a minimum near 76 km to a maximum near 90 km. The uncertainty in the inferred altitude of the peak emission, which includes a contribution for atmospheric extinction, was estimated to be ±2.7 km and is comparable with the ±2.6 km value quoted for the nominal altitude (87 km of the OH layer. Longer periods of overlap of satellite and ground-based measurements together with simultaneous on-site measurements of atmospheric extinction could reduce the uncertainty to approximately 2 km.

  3. Waste-surface mapping of the Fernald K-65 silos using a structured light measurement system

    International Nuclear Information System (INIS)

    Burks, B.L.; DePiero, F.W.; Dinkins, M.A.; Rowe, J.C.; Selleck, C.B.; Jacoboski, D.L.

    1992-10-01

    A remotely operated surface-mapping measurement system was developed by the Robotics ampersand Process Systems Division at Oak Ridge National Laboratory for use in the K-65 waste-storage silos at Fernald, Ohio. The mapping system used three infrared line-generating laser diodes as illumination sources and three high-resolution, low-lux, calibrated, black-and-white, charge-coupled-device video cameras as receivers. These components were combined to form structured light source range and direction sensors with six different possible emitter-receiver pairs. A technology demonstration and predeployment tests were performed at Fernald using the empty Silo 4 into which was placed rectangular objects of known dimensions. These objects were scanned by the structured light sources to demonstrate functionality and verify that the system was giving sufficiently accurate range data in three dimensions. The structured light sources were deployed in Silos 1 and 2 to scan the waste surfaces. The resulting data were merged to create three-dimensional maps of those surfaces. A bentonite clay cap was placed over the waste surfaces and surface maps were obtained. The change in surface height before and after bentonite addition was utilized as a measure of clay cap thickness

  4. Partial compensation interferometry for measurement of surface parameter error of high-order aspheric surfaces

    Science.gov (United States)

    Hao, Qun; Li, Tengfei; Hu, Yao

    2018-01-01

    Surface parameters are the properties to describe the shape characters of aspheric surface, which mainly include vertex radius of curvature (VROC) and conic constant (CC). The VROC affects the basic properties, such as focal length of an aspheric surface, while the CC is the basis of classification for aspheric surface. The deviations of the two parameters are defined as surface parameter error (SPE). Precisely measuring SPE is critical for manufacturing and aligning aspheric surface. Generally, SPE of aspheric surface is measured directly by curvature fitting on the absolute profile measurement data from contact or non-contact testing. And most interferometry-based methods adopt null compensators or null computer-generated holograms to measure SPE. To our knowledge, there is no effective way to measure SPE of highorder aspheric surface with non-null interferometry. In this paper, based on the theory of slope asphericity and the best compensation distance (BCD) established in our previous work, we propose a SPE measurement method for high-order aspheric surface in partial compensation interferometry (PCI) system. In the procedure, firstly, we establish the system of two element equations by utilizing the SPE-caused BCD change and surface shape change. Then, we can simultaneously obtain the VROC error and CC error in PCI system by solving the equations. Simulations are made to verify the method, and the results show a high relative accuracy.

  5. Automatic Measurement of Low Level Contamination on Concrete Surfaces

    International Nuclear Information System (INIS)

    Tachibana, M.; Itoh, H.; Shimada, T.; Yanagihara, S.

    2002-01-01

    Automatic measurement of radioactivity is necessary for considering cost effectiveness in final radiological survey of building structures in decommissioning nuclear facilities. The RAPID (radiation measuring pilot device for surface contamination) was developed to be applied to automatic measurement of low level contamination on concrete surfaces. The RAPID has a capability to measure contamination with detection limit of 0.14 Bq/cm2 for 60Co in 30 seconds of measurement time and its efficiency is evaluated to be 5 m2/h in a normal measurement option. It was confirmed that low level contamination on concrete surfaces could be surveyed by the RAPID efficiently compared with direct measurement by workers through its actual application

  6. Open questions in surface topography measurement: a roadmap

    International Nuclear Information System (INIS)

    Leach, Richard; Evans, Christopher; He, Liangyu; Davies, Angela; Duparré, Angela; Henning, Andrew; Jones, Christopher W; O’Connor, Daniel

    2015-01-01

    Control of surface topography has always been of vital importance for manufacturing and many other engineering and scientific disciplines. However, despite over one hundred years of quantitative surface topography measurement, there are still many open questions. At the top of the list of questions is ‘Are we getting the right answer?’ This begs the obvious question ‘How would we know?’ There are many other questions relating to applications, the appropriateness of a technique for a given scenario, or the relationship between a particular analysis and the function of the surface. In this first ‘open questions’ article we have gathered together some experts in surface topography measurement and asked them to address timely, unresolved questions about the subject. We hope that their responses will go some way to answer these questions, address areas where further research is required, and look at the future of the subject. The first section ‘Spatial content characterization for precision surfaces’ addresses the need to characterise the spatial content of precision surfaces. Whilst we have been manufacturing optics for centuries, there still isn’t a consensus on how to specify the surface for manufacture. The most common three methods for spatial characterisation are reviewed and compared, and the need for further work on quantifying measurement uncertainties is highlighted. The article is focussed on optical surfaces, but the ideas are more pervasive. Different communities refer to ‘figure, mid-spatial frequencies, and finish’ and ‘form, waviness, and roughness’, but the mathematics are identical. The second section ‘Light scattering methods’ is focussed on light scattering techniques; an important topic with in-line metrology becoming essential in many manufacturing scenarios. The potential of scattering methods has long been recognized; in the ‘smooth surface limit’ functionally significant relationships can be derived from first

  7. Patterns of the loop current system and regions of sea surface height variability in the eastern Gulf of Mexico revealed by the self-organizing maps

    Science.gov (United States)

    Liu, Yonggang; Weisberg, Robert H.; Vignudelli, Stefano; Mitchum, Gary T.

    2016-04-01

    The Self-Organizing Map (SOM), an unsupervised learning neural network, is employed to extract patterns evinced by the Loop Current (LC) system and to identify regions of sea surface height (SSH) variability in the eastern Gulf of Mexico (GoM) from 23 years (1993-2015) of altimetry data. Spatial patterns are characterized as different LC extensions and different stages in the process of LC eddy shedding. The temporal evolutions and the frequency of occurrences of these patterns are obtained, and the typical trajectories of the LC system progression on the SOM grid are investigated. For an elongated, northwest-extended, or west-positioned LC, it is common for the LC anticyclonic eddy (LCE) to separate and propagate into the western GoM, while an initially separated LCE in close proximity to the west Florida continental slope often reattaches to the LC and develops into an elongated LC, or reduces intensity locally before moving westward as a smaller eddy. Regions of differing SSH variations are also identified using the joint SOM-wavelet analysis. Along the general axis of the LC, SSH exhibits strong variability on time scales of 3 months to 2 years, also with energetic intraseasonal variations, which is consistent with the joint Empirical Orthogonal Function (EOF)-wavelet analysis. In the more peripheral regions, the SSH has a dominant seasonal variation that also projects across the coastal ocean. The SOM, when applied to both space and time domains of the same data, provides a powerful tool for diagnosing ocean processes from such different perspectives.

  8. Intraseasonal-to-semiannual variability of sea-surface height in the astern, equatorial Indian Ocean and southern Bay of Bengal

    Science.gov (United States)

    Cheng, Xuhua; McCreary, Julian P.; Qiu, Bo; Qi, Yiquan; Du, Yan

    2017-05-01

    Intraseasonal-to-semiannual variability of sea-surface height (SSH) in the eastern, equatorial Indian Ocean (EEIO) and southern Bay of Bengal (BoB) is investigated using altimetric data, and solutions to 1½ layer (first baroclinic mode) and linear, continuously stratified (LCS; multibaroclinic-mode) models. The amplitude and dominant periods of SSH variability differ regionally. Large-amplitude variability is found along the west coast of Sumatra, in a zonal band across the BoB centered along 5°N, east of Sri Lanka, and in the northwestern BoB, respectively. Along the Sumatran west coast, SSH variability peaks at 30-60, 90, and 180 days. Along 5°N and east of Sri Lanka, the 30-60 day variability is dominant. Sensitivity experiments using a nonlinear version of the 1½ layer model forced by realistic winds reproduce the observed patterns of intraseasonal variability in the southern BoB. At 30-60 days, the solutions show that eddies (nonlinear Rossby waves) propagating from the east, rather than local wind forcing, account for most of the variance east of Sri Lanka; furthermore, they demonstrate that the variance is significantly enhanced by the nonlinear transfer of 90-120 day energy into the intraseasonal band of 30-60 days. The LCS solutions show that the first two baroclinic modes explain most of the SSH variance at 90-180 days. The second baroclinic mode dominates the SSH variance at 180 days, a consequence of basin resonance and strong wind forcing.

  9. Measurement of Dynamic Friction Coefficient on the Irregular Free Surface

    International Nuclear Information System (INIS)

    Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.

    2007-01-01

    A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator

  10. Measurement of near neighbor separations of surface atoms

    International Nuclear Information System (INIS)

    Cohen, P.I.

    Two techniques are being developed to measure the nearest neighbor distances of atoms at the surfaces of solids. Both measures extended fine structure in the excitation probability of core level electrons which are excited by an incident electron beam. This is an important problem because the structures of most surface systems are as yet unknown, even though the location of surface atoms is the basis for any quantitative understanding of the chemistry and physics of surfaces and interfaces. These methods would allow any laboratory to make in situ determinations of surface structure in conjunction with most other laboratory probes of surfaces. Each of these two techniques has different advantages; further, the combination of the two will increase confidence in the results by reducing systematic error in the data analysis

  11. A color-coded tape for uterine height measurement: a tool to identify preterm pregnancies in low resource settings.

    Directory of Open Access Journals (Sweden)

    Fernando Althabe

    Full Text Available Neonatal mortality associated with preterm birth can be reduced with antenatal corticosteroids (ACS, yet 36.0 weeks GA. In phase 1, UH measurements were collected prospectively in the Democratic Republic of Congo, India and Pakistan, using distinct tapes to address variation across regions and ethnicities. In phase 2, we tested accuracy in 250 pregnant women with known GA from early ultrasound enrolled at prenatal clinics in Argentina, India, Pakistan and Zambia. Providers masked to the ultrasound GA measured UH. Receiver operating characteristics (ROC analysis was conducted.1,029 pregnant women were enrolled. In all countries the tapes were most effective identifying pregnancies between 20.0-35.6 weeks, compared to the other GAs. The ROC areas under the curves and 95% confidence intervals were: Argentina 0.69 (0.63, 0.74; Zambia 0.72 (0.66, 0.78, India 0.84 (0.80, 0.89, and Pakistan 0.83 (0.78, 0.87. The sensitivity and specificity (and 95% confidence intervals for identifying pregnancies between 20.0-35.6 weeks, respectively, were: Argentina 87% (82%-92% and 51% (42%-61%; Zambia 91% (86%-95% and 50% (40%-60%; India 78% (71%-85% and 89% (83%-94%; Pakistan 63% (55%-70% and 94% (89%-99%.We observed moderate-good accuracy identifying pregnancies ≤ 35.6 weeks gestation, with potential usefulness at the community level in low-middle income countries to facilitate the preterm identification and interventions to reduce preterm neonatal mortality. Further research is needed to validate these findings on a population basis.

  12. Surface deposition measurements of the TMI-2 gross decontamination experiment

    International Nuclear Information System (INIS)

    McIssac, C.V.; Hetzer, D.C.

    1982-01-01

    In order to measure the effectiveness of the gross decontamination experiment (principally a water spray technique) performed in the TMI-2 reactor building, the Technical Information and Examination Program's Radiation and Environment personnel made surface activity measurements before and after the experiment. In conjunction with surface sampling, thermoluminescent dosimeter (TLD) and gamma spectrometry measurements were also performed to distinguish between radiation fields and contamination. The surface sampler used to collect samples from external surfaces within the reactor building is a milling tool having four major components: a 1.27-cm constant-speed drill; a drill support assembly that allows setting sample penetration depth; filter cartridges for intake air purification and sample collection; and an air pump that forces air across the surface being sampled and through the sample filter cartridge

  13. Fear of heights and visual height intolerance.

    Science.gov (United States)

    Brandt, Thomas; Huppert, Doreen

    2014-02-01

    The aim of this review is, first, to cover the different aspects of visual height intolerance such as historical descriptions, definition of terms, phenomenology of the condition, neurophysiological control of gaze, stance and locomotion, and therapy, and, second, to identify warranted epidemiological and experimental studies. Vivid descriptions of fear of heights can be found in ancient texts from the Greek, Roman, and Chinese classics. The life-time prevalence of visual height intolerance is as high as 28% in the general population, and about 50% of those who are susceptible report an impact on quality of life. When exposed to heights, visual exploration by eye and head movements is restricted, and the velocity of locomotion is reduced. Therapy for fear of heights is dominated by the behavioral techniques applied during real or virtual reality exposure. Their efficacy might be facilitated by the administration of D-cycloserine or glucocorticoids. Visual height intolerance has a considerable impact on daily life and interpersonal interactions. It is much more frequent than fear of heights, which is defined as an environmental subtype of a specific phobia. There is certainly a continuum stretching from acrophobia to a less-pronounced visual height intolerance, to which the categorical distinction of a specific phobia does not apply.

  14. Variability of the Mixed-Layer Height Over Mexico City

    Science.gov (United States)

    García-Franco, J. L.; Stremme, W.; Bezanilla, A.; Ruiz-Angulo, A.; Grutter, M.

    2018-02-01

    The diurnal and seasonal variability of the mixed-layer height in urban areas has implications for ground-level air pollution and the meteorological conditions. Measurements of the backscatter of light pulses with a commercial lidar system were performed for a continuous period of almost six years between 2011 and 2016 in the southern part of Mexico City. The profiles were temporally and vertically smoothed, clouds were filtered out, and the mixed-layer height was determined with an ad hoc treatment of both the filtered and unfiltered profiles. The results are in agreement when compared with values of mixed-layer height reconstructed from, (i) radiosonde data, and (ii) surface and vertical column densities of a trace gas. The daily maxima of the mean mixed-layer height reach values > 3 km above ground level in the months of March-April, and are clearly lower (pollution episodes and the height of the mixed layer. The growth rate of the convective mixed-layer height has a seasonal behaviour, which is characterized together with the mixed-layer-height anomalies. A clear residual layer is evident from the backscattered signals recorded in days with specific atmospheric conditions, but also from the cloud-filtered mean diurnal profiles. The occasional presence of a residual layer results in an overestimation of the reported mixed-layer height during the night and early morning hours.

  15. Surface and interfacial tension measurement, theory, and applications

    CERN Document Server

    Hartland, Stanley

    2004-01-01

    This edited volume offers complete coverage of the latest theoretical, experimental, and computer-based data as summarized by leading international researchers. It promotes full understanding of the physical phenomena and mechanisms at work in surface and interfacial tensions and gradients, their direct impact on interface shape and movement, and their significance to numerous applications. Assessing methods for the accurate measurement of surface tension, interfacial tension, and contact angles, Surface and Interfacial Tension presents modern simulations of complex interfacial motions, such a

  16. A computer-aided surface roughness measurement system

    International Nuclear Information System (INIS)

    Hughes, F.J.; Schankula, M.H.

    1983-11-01

    A diamond stylus profilometer with computer-based data acquisitions/analysis system is being used to characterize surfaces of reactor components and materials, and to examine the effects of surface topography on thermal contact conductance. The current system is described; measurement problems and system development are discussed in general terms and possible future improvements are outlined

  17. Measuring Forces between Oxide Surfaces Using the Atomic Force Microscope

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

    The interactions between colloidal particles play a major role in processing of ceramics, especially in casting processes. With the Atomic Force Microscope (AFM) it is possible to measure the inter-action force between a small oxide particle (a few micron) and a surface as function of surface...

  18. Drop shape visualization and contact angle measurement on curved surfaces.

    Science.gov (United States)

    Guilizzoni, Manfredo

    2011-12-01

    The shape and contact angles of drops on curved surfaces is experimentally investigated. Image processing, spline fitting and numerical integration are used to extract the drop contour in a number of cross-sections. The three-dimensional surfaces which describe the surface-air and drop-air interfaces can be visualized and a simple procedure to determine the equilibrium contact angle starting from measurements on curved surfaces is proposed. Contact angles on flat surfaces serve as a reference term and a procedure to measure them is proposed. Such procedure is not as accurate as the axisymmetric drop shape analysis algorithms, but it has the advantage of requiring only a side view of the drop-surface couple and no further information. It can therefore be used also for fluids with unknown surface tension and there is no need to measure the drop volume. Examples of application of the proposed techniques for distilled water drops on gemstones confirm that they can be useful for drop shape analysis and contact angle measurement on three-dimensional sculptured surfaces. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Device for radiometric measurement, e.g. of surface density

    International Nuclear Information System (INIS)

    Gregor, J.; Kopl, F.

    1973-01-01

    A design is described of a device for radiometric measurements, such as of material surface density, thickness of coating layers, surface moisture, and for the analysis of chemical composition. The device uses backscattered radiation indicated by two ionization chambers with gas filling; the radiation source is placed in between the chambers. (J.K.)

  20. Laboratory measurements of dusty surface charging in plasma.

    Science.gov (United States)

    Chou, Kevin; Wang, Joseph

    2017-09-01

    A novel method is developed to study the charging of a conducting surface covered by a thin dust layer in plasma. The potential profile in the dust layer and the floating potential of the surface underneath are measured directly by embedding conducting wires in the dust and connecting the wires to a measurement plate outside the vacuum chamber, where a Trek non-contacting electrostatic voltmeter measures the floating potential of the measurement plate. Laboratory experiments are carried out to study plasma charging of a conducting plate covered by lunar dust simulant, JSC-1A. The results show that the plate potential is dependent on both the ambient plasma condition and the dust layer thickness. The current balance condition controls the floating potential of the dust surface while the dust layer acts as a capacitor and controls the potential of the plate with respect to the dust surface. Hence, a dust covered conducting plate will be charged more negatively than a clean plate.

  1. Accuracy of Surface Plate Measurements - General Purpose Software for Flatness Measurement

    NARCIS (Netherlands)

    Meijer, J.; Heuvelman, C.J.

    1990-01-01

    Flatness departures of surface plates are generally obtained from straightness measurements of lines on the surface. A computer program has been developed for on-line measurement and evaluation, based on the simultaneous coupling of measurements in all grid points. Statistical methods are used to

  2. Сomposition and ratio of the chemical elements on the surfaces different by height of reindeer lichen podetia Cladonia rangiferina

    Directory of Open Access Journals (Sweden)

    Byazrov Lev

    2016-06-01

    Full Text Available In the paper the composition of 21 elements – Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ba, Pb – was compared in the upper, central, and lower parts of podetia surfaces of the reindeer lichen Cladonia rangiferina, sampled on the slope of Barguzinsky chain. For the measurement of the elements content (%, a sample-nondestructive μ-XRF spectrometer was used. It was stated that the share (% of the most elements, except for Cu and Zn, was highly variable. The content of the elements on the surfaces differs significantly between the studied parts of C. rangiferina podetia: mean values of the content of P, S, Cl, and K were statistically higher on the surface of the upper part of podetia, while those of Al, Si, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Co, and the total content – on the surface of the lower part of podetia. On all the parts of podetia very high value of the enrichment factor for As and Pb was established, and It was increased for P, Co, Ni, Cu, Zn.

  3. The Use of MERRA-2 Near Surface Meteorology to Understand the Behavior of Planetary Boundary Layer heights Derived from Wind Profiler Data Over the US Great Plains

    Science.gov (United States)

    Molod, A.; Salmun, H.; Collow, A.

    2017-12-01

    The atmospheric general circulation model (GCM) that underlies the MERRA-2 reanalysis includesa suite of physical parameterizations that describe the processes that occur in theplanetary boundary layer (PBL). The data assimilation system assures that the atmosphericstate variables used as input to these parameterizations are constrained to the bestfit to all of the available observations. Many studies, however, have shown that the GCM-based estimates of MERRA-2 PBL heights are biased high, and so are not reliable forapplication related to constituent transport or the carbon cycle.A new 20-year record of PBL heights was derived from Wind Profiler (WP) backscatter data measuredat a wide network of stations throughout the US Great Plains and has been validated against independent estimates. The behavior of these PBL heights shows geographical and temporalvariations that are difficult to attribute to particular physical processes withoutadditional information that are not part of the observational record.In the present study, we use information on physical processes from MERRA-2 to understand the behavior of the WP derived PBL heights. The behavior of the annual cycle of both MERRA-2 and WP PBL heights shows three classes of behavior: (i) canonical, where the annual cyclefollows the annual cycle of the sun, (ii) delayed, where the PBL height reaches its annual maximum after the annual maximum of the solar insolation, and (iii) double maxima, wherethe PBL height begins to rise with the solar insolation but falls sometimes during the the summer and then rises again. Although the magnitude of these types of variations isdescribed by the WP PBL record, the explanation for these behaviors and the relationshipto local precipitation, temperature, hydrology and sensible and latent heat fluxes is articulated using information from MERRA-2.

  4. Cantilever measurements of surface stress, surface reconstruction, film stress and magnetoelastic stress of monolayersc

    Directory of Open Access Journals (Sweden)

    Jürgen Kirschner

    2008-07-01

    Full Text Available We review the application of cantilever-based stress measurements in surface science and magnetism. The application of thin (thickness appr. 0.1 mm single crystalline substrates as cantilevers has been used successfully to measure adsorbate-induced surface stress changes, lattice misfit induced film stress, and magneto-elastic stress of ferromagnetic monolayers. Surface stress changes as small as 0.01 N/m can be readily measured, and this translates into a sensitivity for adsorbate-coverage well below 0.01 of one layer. Stress as large as several GPa, beyond the elasticity limits of high strength materials, is measured, and it is ascribed to the lattice misfit between film and substrate. Our results point at the intimate relation between surface stress and surface reconstruction, stress-induced structural changes in epitaxially strained films, and strain-induced modifications of the magneto-elastic coupling in ferromagnetic monolayers.

  5. Cantilever measurements of surface stress, surface reconstruction, film stress and magnetoelastic stress of monolayers.

    Science.gov (United States)

    Sander, Dirk; Tian, Zhen; Kirschner, Jürgen

    2008-07-29

    We review the application of cantilever-based stress measurements in surface science and magnetism. The application of thin (thickness appr. 0.1 mm) single crystalline substrates as cantilevers has been used successfully to measure adsorbate-induced surface stress changes, lattice misfit induced film stress, and magneto-elastic stress of ferromagnetic monolayers. Surface stress changes as small as 0.01 N/m can be readily measured, and this translates into a sensitivity for adsorbate-coverage well below 0.01 of one layer. Stress as large as several GPa, beyond the elasticity limits of high strength materials, is measured, and it is ascribed to the lattice misfit between film and substrate. Our results point at the intimate relation between surface stress and surface reconstruction, stress-induced structural changes in epitaxially strained films, and strain-induced modifications of the magneto-elastic coupling in ferromagnetic monolayers.

  6. Maternal nutritional status (as measured by height, weight and BMI) in Bangladesh: trends and socio-economic association over the period 1996 to 2007.

    Science.gov (United States)

    Mohsena, Masuda; Goto, Rie; Mascie-Taylor, Cg Nicholas

    2016-06-01

    To analyse trends in maternal nutritional status in Bangladesh over a 12-year period and to examine the associations between nutritional status and socio-economic variables. Maternal nutritional status indicators were height, weight and BMI. Socio-economic variables used were region, residency, education and occupation of the mothers and their husbands, house type, and possession score in the household. Bangladesh Demographic and Health Surveys (1996, 2000, 2004 and 2007) were the source of data. A total of 16 278 mothers were included. All of the socio-economic variables showed significant associations with maternal nutritional status indicators. Regional variation was found to be present; all three indicators were found to be lowest in the Sylhet division. Upward trends in maternal height, weight and BMI were evident from no possessions to four possessions in households, and for no education to higher education of women and their husbands. Bangladeshi mothers measured in 2007 were found to be on average 0·34 cm taller and 3·36 kg heavier than mothers measured in 1996. Between 1996 and 2007 maternal underweight fell from nearly 50 % to just over 30 % while overweight and obesity increased from about 3 % to over 9 % (WHO cut-offs) or from 7 % to nearly 18 % (Asian cut-offs). The study reveals that over the 12-year period in Bangladesh there has been a substantial reduction in maternal underweight accompanied by a considerable increase in obesity. It is also evident that malnutrition in Bangladesh is a multidimensional problem that warrants a proper policy mix and programme intervention.

  7. A study of Arctic sea ice freeboard heights, gravity anomalies and dynamic topography from ICESat measurementes

    DEFF Research Database (Denmark)

    Skourup, Henriette

    The Arctic sea ice cover has a great influence on the climate and is believed to respond rapidly to climate changes. Since 2003 the Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry mission has provided satellite altimetry over the ice covered Arctic Ocean up to 86 N. In this thesis......, the main topic is to estimate the sea surface height in the Arctic Ocean from ICESat laser altimetry data and to use this information to estimate sea ice freeboard heights, gravity anomalies and mean dynamic topography. The laser altimeter measures the height of the surface topography, which in the Arctic...... is a combination of sea ice and open water. The sea surface height is found by a "lowest-level" filtering procedure, originally developed for airborne lidar measurements, which assumes that the lowest levels measured represent the open water in the ice pack. The sea surface obtained this way is used to estimate...

  8. Measuring evaporation from soil surfaces for environmental and ...

    African Journals Online (AJOL)

    ... in many aspects of environmental geotechnics and waste management. The paper describes the measurements made to assess the surface energy balance as well as its analysis, and presents the results of typical measurements. It also presents numerical values of the parameters and constants needed for the analysis.

  9. Sensitivity of surface resistance measurement of HTS thin films by ...

    Indian Academy of Sciences (India)

    field distribution in the resonators. The microwave surface resistance of the superconducting sample is then extracted from the measured Q value as a function of temperature. The sensitivity of the Rs measurement, that is, the relative change in the Q value with the change in the Rs value is determined for each resonator.

  10. Measurement of tendon reflexes by surface electromyography in normal subjects

    NARCIS (Netherlands)

    Stam, J.; van Crevel, H.

    1989-01-01

    A simple method for measuring the tendon reflexes was developed. A manually operated, electronic reflex hammer was applied that enabled measurement of the strength of tendon taps. Reflex responses were recorded by surface electromyography. Stimulus-response relations and latencies of tendon reflexes

  11. Estimating the breast surface using UWB microwave monostatic backscatter measurements.

    Science.gov (United States)

    Winters, David W; Shea, Jacob D; Madsen, Ernest L; Frank, Gary R; Van Veen, Barry D; Hagness, Susan C

    2008-01-01

    This paper presents an algorithm for estimating the location of the breast surface from scattered ultrawideband (UWB) microwave signals recorded across an antenna array. Knowing the location of the breast surface can improve imaging performance if incorporated as a priori information into recently proposed microwave imaging algorithms. These techniques transmit low-power microwaves into the breast using an antenna array, which in turn measures the scattered microwave signals for the purpose of detecting anomalies or changes in the dielectric properties of breast tissue. Our proposed surface identification algorithm consists of three procedures, the first of which estimates M points on the breast surface given M channels of measured microwave backscatter data. The second procedure applies interpolation and extrapolation to these M points to generate N > M points that are approximately uniformly distributed over the breast surface, while the third procedure uses these N points to generate a 3-D estimated breast surface. Numerical as well as experimental tests indicate that the maximum absolute error in the estimated surface generated by the algorithm is on the order of several millimeters. An error analysis conducted for a basic microwave radar imaging algorithm (least-squares narrowband beamforming) indicates that this level of error is acceptable. A key advantage of the algorithm is that it uses the same measured signals that are used for UWB microwave imaging, thereby minimizing patient scan time and avoiding the need for additional hardware.

  12. Mapping surface soil moisture with L-band radiometric measurements

    Science.gov (United States)

    Wang, James R.; Shiue, James C.; Schmugge, Thomas J.; Engman, Edwin T.

    1989-01-01

    A NASA C-130 airborne remote sensing aircraft was used to obtain four-beam pushbroom microwave radiometric measurements over two small Kansas tall-grass prairie region watersheds, during a dry-down period after heavy rainfall in May and June, 1987. While one of the watersheds had been burned 2 months before these measurements, the other had not been burned for over a year. Surface soil-moisture data were collected at the time of the aircraft measurements and correlated with the corresponding radiometric measurements, establishing a relationship for surface soil-moisture mapping. Radiometric sensitivity to soil moisture variation is higher in the burned than in the unburned watershed; surface soil moisture loss is also faster in the burned watershed.

  13. Indirect measurement of near-surface velocity and pressure fields based on measurement of moving free surface profiles

    International Nuclear Information System (INIS)

    Sibamoto, Yasuteru; Nakamura, Hideo

    2005-01-01

    A non-intrusive technique for measurement of the velocity and pressure fields adjacent to a moving fluid surface is developed. The technique is based on the measurement of fluid surface profile. The velocity and pressure fields are derived with use of the boundary element method (BEM) by seeking for an incompressible flow field that satisfies the kinematic boundary condition imposed by the time-dependent fluid surface profile. The proposed technique is tested by deriving the velocity and pressure fields inversely from the fluid surface profiles obtained by a forward BEM calculation of fluid surface response to externally-imposed pressure. The inverse calculation results show good agreement with the imposed pressure distribution in the forward calculation. (author)

  14. Global Distribution of Planetary Boundary Layer Height Derived from CALIPSO

    Science.gov (United States)

    Huang, J.

    2015-12-01

    The global distribution of planetary boundary layer (PBL) height, which was estimated from the attenuated back-scatter observations of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), is presented. In general, the PBL is capped by a temperature inversion that tends to trap moisture and aerosols. The gradient of back-scatter observed by lidar is almost always associated with this temperature inversion and the simultaneous decrease of moisture content. Thus, the PBL top is defined as the location of the maximum aerosol scattering gradient, which is analogous to the more conventional thermodynamic definition. The maximum standard deviation method, developed by Jordan et al. (2010), is modified and used to derive the global PBL heights. The derived PBL heights are not only consistent with the results of McGrath-Spangler and Denning (2012) but also agree well with the ground-based lidar measurements. It is found that the correlation between CALIPSO and the ground-based lidar was 0.73. The seasonal mean patterns from 4-year mid-day PBL heights over global are demonstrated. Also it is found that the largest PBL heights occur over the Tibetan Plateau and the coastal areas. The smallest PBL heights appear in the Tarim Basin and the northeast of China during the local winter. The comparison of PBL heights from CALIPSO and ECMWF under different land-cover conditions showed that, over ocean and forest surface, the PBL height estimated from the CALIPSO back-scatter climatology is larger than the ones estimated from ECMWF data. However, the PBL heights from ECMWF, over grass land and bare land surface in spring and summer are larger than the ones from CALIPSO.

  15. Roughness in Surface Force Measurements: Extension of DLVO Theory To Describe the Forces between Hafnia Surfaces.

    Science.gov (United States)

    Eom, Namsoon; Parsons, Drew F; Craig, Vincent S J

    2017-07-06

    The interaction between colloidal particles is commonly viewed through the lens of DLVO theory, whereby the interaction is described as the sum of the electrostatic and dispersion forces. For similar materials acting across a medium at pH values remote from the isoelectric point the theory typically involves an electrostatic repulsion that is overcome by dispersion forces at very small separations. However, the dominance of the dispersion forces at short separations is generally not seen in force measurements, with the exception of the interaction between mica surfaces. The discrepancy for silica surfaces has been attributed to hydration forces, but this does not explain the situation for titania surfaces where the dispersion forces are very much larger. Here, the interaction forces between very smooth hafnia surfaces have been measured using the colloid probe technique and the forces evaluated within the DLVO framework, including both hydration forces and the influence of roughness. The measured forces across a wide range of pH at different salt concentrations are well described with a single parameter for the surface roughness. These findings show that even small degrees of surface roughness significantly alter the form of the interaction force and therefore indicate that surface roughness needs to be included in the evaluation of surface forces between all surfaces that are not ideally smooth.

  16. Measuring and modeling surface sorption dynamics of organophosphate flame retardants on impervious surfaces

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data presented in this data file is a product of a journal publication. The dataset contains measured and model predicted OPFRs gas-phase and surface-phase...

  17. Surface Moisture Measurement System Operation and Maintenance Manual

    International Nuclear Information System (INIS)

    Ritter, G.A.; Pearce, K.L.; Stokes, T.L.

    1995-12-01

    This operations and maintenance manual addresses deployment, equipment and field hazards, operating instructions, calibration verification, removal, maintenance, and other pertinent information necessary to safely operate and store the Surface Moisture Measurement System (SMMS) and Liquid Observation Well Moisture Measurement System (LOWMMS). These systems were developed primarily in support of Tank Waste Remediation System (TWRS) Safety Programs for moisture measurement in organic and ferrocyanide watch list tanks

  18. Practical aspects of tritium measurement in ground and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Nitzsche, O. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik; Hebert, D. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik

    1997-03-01

    Tritium measurements are a powerful tool in hydrological and hydrogeological investigations for detecting mean residence times of several water reservoirs. Due to the low tritium activities in precipitation, ground and surface waters a low level measurement is necessary. Therefore often the liquid scintillation counting after an electrolytic enrichment of water is used. In this paper some practical aspects and problems of measurement are discussed and the problem of contamination in low level laboratories is shown. (orig.)

  19. The surface elevation table: marker horizon method for measuring wetland accretion and elevation dynamics

    Science.gov (United States)

    Callaway, John C.; Cahoon, Donald R.; Lynch, James C.

    2014-01-01

    Tidal wetlands are highly sensitive to processes that affect their elevation relative to sea level. The surface elevation table–marker horizon (SET–MH) method has been used to successfully measure these processes, including sediment accretion, changes in relative elevation, and shallow soil processes (subsidence and expansion due to root production). The SET–MH method is capable of measuring changes at very high resolution (±millimeters) and has been used worldwide both in natural wetlands and under experimental conditions. Marker horizons are typically deployed using feldspar over 50- by 50-cm plots, with replicate plots at each sampling location. Plots are sampled using a liquid N2 cryocorer that freezes a small sample, allowing the handling and measurement of soft and easily compressed soils with minimal compaction. The SET instrument is a portable device that is attached to a permanent benchmark to make high-precision measurements of wetland surface elevation. The SET instrument has evolved substantially in recent decades, and the current rod SET (RSET) is widely used. For the RSET, a 15-mm-diameter stainless steel rod is pounded into the ground until substantial resistance is achieved to establish a benchmark. The SET instrument is attached to the benchmark and leveled such that it reoccupies the same reference plane in space, and pins lowered from the instrument repeatedly measure the same point on the soil surface. Changes in the height of the lowered pins reflect changes in the soil surface. Permanent or temporary platforms provide access to SET and MH locations without disturbing the wetland surface.

  20. Plastic Deformations of Measured Object Surface in Contact with Undeformable Surface of Measuring Tool

    Directory of Open Access Journals (Sweden)

    Kowalik Marek

    2016-10-01

    Full Text Available Measuring errors caused by deformation (flattening of a measured object appear under the influence of pressure force and weight of the measured object. Plastic strain, arising at the contact of a measured object and an undeformable contact tip of a measuring device, can be calculated by applying the Hertz plastic solution and the hypothesis of plastic strain. In a small area of contact between two bodies pressing against one another with force F, there appears the so-called contact stress. It can sometime reach very high values, exceeding the yield point, even when the contact pressure is relatively small. In the present work, the authors describe a theoretical solution to the problem of plastic strain between two bodies. The derived relationships enable to calculate force F during measurements of a deformable object by means of an instrument with an undeformable, spherical measuring tip. By applying the τmax hypothesis, a solution was obtained for the force F in an inexplicit form. The theoretical solution was verified with the digital simulation and experimental measurement. With the FEM method, the limit length gage was modeled in interaction with the measured shaft of a diameter d larger than the nominal one of Δl value.

  1. Plastic Deformations of Measured Object Surface in Contact with Undeformable Surface of Measuring Tool

    Science.gov (United States)

    Kowalik, Marek; Rucki, Mirosław; Paszta, Piotr; Gołębski, Rafał

    2016-10-01

    Measuring errors caused by deformation (flattening) of a measured object appear under the influence of pressure force and weight of the measured object. Plastic strain, arising at the contact of a measured object and an undeformable contact tip of a measuring device, can be calculated by applying the Hertz plastic solution and the hypothesis of plastic strain. In a small area of contact between two bodies pressing against one another with force F, there appears the so-called contact stress. It can sometime reach very high values, exceeding the yield point, even when the contact pressure is relatively small. In the present work, the authors describe a theoretical solution to the problem of plastic strain between two bodies. The derived relationships enable to calculate force F during measurements of a deformable object by means of an instrument with an undeformable, spherical measuring tip. By applying the τmax hypothesis, a solution was obtained for the force F in an inexplicit form. The theoretical solution was verified with the digital simulation and experimental measurement. With the FEM method, the limit length gage was modeled in interaction with the measured shaft of a diameter d larger than the nominal one of Δl value.

  2. Interferometric method for measuring high velocities of diffuse surfaces

    International Nuclear Information System (INIS)

    Maron, Y.

    1978-01-01

    An interferometric method for measuring the displacement of diffuse surfaces moving with velocities of a few microsecond is presented. The method utilizes the interference between two light beams reflected from a constant area of the moving surface at two different angles. It enables the detection of high rate velocity variations. Light source of a fairly low temporal coherence and power around 100mW is needed. (author)

  3. Verification of Geosat sea surface topography in the Gulf Stream extension with surface drifting buoys and hydrographic measurements

    Science.gov (United States)

    Willebrand, J.; KäSe, R. H.; Stammer, D.; Hinrichsen, H.-H.; Krauss, W.

    1990-03-01

    Altimeter data from Geosat have been analyzed in the Gulf Stream extension area. Horizontal maps of the sea surface height anomaly relative to an annual mean for various 17-day intervals were constructed using an objective mapping procedure. The mean sea level was approximated by the dynamic topography from climatological hydrographic data. Geostrophic surface velocities derived from the composite maps (mean plus anomaly) are significantly correlated with surface drifter velocities observed during an oceanographie experiment in the spring of 1987. The drifter velocities contain much energy on scales less than 100 km which are not resolved in the altimetric maps. It is shown that the composite sea surface height also agrees well with ground verification from hydrographic data along sections in a triangle between the Azores, Newfoundland, and Bermuda, except in regions of high mean gradients.

  4. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    Road surface reflection data in the form of standard r-tables serve as input for design calculations of road lighting installations on traffic roads. However, in several countries the use of the standard r-tables has not been verified by measurement in a long period of time, while the types of road...... surfaces in use have changed - for instance to road surface types with less noise from wheel passages. Because of this, a co-operation between the road administrations of the Nordic countries (abbreviated NMF) decided to construct a portable instrument to be used on selections of traffic roads within...

  5. Experimental Method for Measuring Dust Load on Surfaces in Rooms

    DEFF Research Database (Denmark)

    Lengweiler, Philip; Nielsen, Peter V.; Moser, Alfred

    , there is a need for better understanding of the mechanism of dust deposition and resuspension. With the presented experimental setup, the dust load on surfaces in a channel can be measured as a function of the environmental and surface conditions and the type of particles under controlled laboratory conditions.......A new experimental setup to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust-related problems in rooms...

  6. Reporting central tendencies of chamber measured surface emission and oxidation.

    Science.gov (United States)

    Abichou, Tarek; Clark, Jeremy; Chanton, Jeffery

    2011-05-01

    Methane emissions, concentrations, and oxidation were measured on eleven MSW landfills in eleven states spanning from California to Pennsylvania during the three year study. The flux measurements were performed using a static chamber technique. Initial concentration samples were collected immediately after placement of the flux chamber. Oxidation of the emitted methane was evaluated using stable isotope techniques. When reporting overall surface emissions and percent oxidation for a landfill cover, central tendencies are typically used to report "averages" of the collected data. The objective of this study was to determine the best way to determine and report central tendencies. Results showed that 89% of the data sets of collected surface flux have lognormal distributions, 83% of the surface concentration data sets are also lognormal. Sixty seven percent (67%) of the isotope measured percent oxidation data sets are normally distributed. The distribution of data for all eleven landfills provides insight of the central tendencies of emissions, concentrations, and percent oxidation. When reporting the "average" measurement for both flux and concentration data collected at the surface of a landfill, statistical analyses provided insight supporting the use of the geometric mean. But the arithmetic mean can accurately represent the percent oxidation, as measured with the stable isotope technique. We examined correlations between surface CH(4) emissions and surface air CH(4) concentrations. Correlation of the concentration and flux values using the geometric mean proved to be a good fit (R(2)=0.86), indicating that surface scans are a good way of identifying locations of high emissions. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Inverse analysis of inner surface temperature history from outer surface temperature measurement of a pipe

    International Nuclear Information System (INIS)

    Kubo, S; Ioka, S; Onchi, S; Matsumoto, Y

    2010-01-01

    When slug flow runs through a pipe, nonuniform and time-varying thermal stresses develop and there is a possibility that thermal fatigue occurs. Therefore it is necessary to know the temperature distributions and the stress distributions in the pipe for the integrity assessment of the pipe. It is, however, difficult to measure the inner surface temperature directly. Therefore establishment of the estimation method of the temperature history on inner surface of pipe is needed. As a basic study on the estimation method of the temperature history on the inner surface of a pipe with slug flow, this paper presents an estimation method of the temperature on the inner surface of a plate from the temperature on the outer surface. The relationship between the temperature history on the outer surface and the inner surface is obtained analytically. Using the results of the mathematical analysis, the inverse analysis method of the inner surface temperature history estimation from the outer surface temperature history is proposed. It is found that the inner surface temperature history can be estimated from the outer surface temperature history by applying the inverse analysis method, even when it is expressed by the multiple frequency components.

  8. Intelligent sampling for the measurement of structured surfaces

    International Nuclear Information System (INIS)

    Wang, J; Jiang, X; Blunt, L A; Scott, P J; Leach, R K

    2012-01-01

    Uniform sampling in metrology has known drawbacks such as coherent spectral aliasing and a lack of efficiency in terms of measuring time and data storage. The requirement for intelligent sampling strategies has been outlined over recent years, particularly where the measurement of structured surfaces is concerned. Most of the present research on intelligent sampling has focused on dimensional metrology using coordinate-measuring machines with little reported on the area of surface metrology. In the research reported here, potential intelligent sampling strategies for surface topography measurement of structured surfaces are investigated by using numerical simulation and experimental verification. The methods include the jittered uniform method, low-discrepancy pattern sampling and several adaptive methods which originate from computer graphics, coordinate metrology and previous research by the authors. By combining the use of advanced reconstruction methods and feature-based characterization techniques, the measurement performance of the sampling methods is studied using case studies. The advantages, stability and feasibility of these techniques for practical measurements are discussed. (paper)

  9. Can foot anthropometric measurements predict dynamic plantar surface contact area?

    Directory of Open Access Journals (Sweden)

    Collins Natalie

    2009-10-01

    Full Text Available Abstract Background Previous studies have suggested that increased plantar surface area, associated with pes planus, is a risk factor for the development of lower extremity overuse injuries. The intent of this study was to determine if a single or combination of foot anthropometric measures could be used to predict plantar surface area. Methods Six foot measurements were collected on 155 subjects (97 females, 58 males, mean age 24.5 ± 3.5 years. The measurements as well as one ratio were entered into a stepwise regression analysis to determine the optimal set of measurements associated with total plantar contact area either including or excluding the toe region. The predicted values were used to calculate plantar surface area and were compared to the actual values obtained dynamically using a pressure sensor platform. Results A three variable model was found to describe the relationship between the foot measures/ratio and total plantar contact area (R2 = 0.77, p R2 = 0.76, p Conclusion The results of this study indicate that the clinician can use a combination of simple, reliable, and time efficient foot anthropometric measurements to explain over 75% of the plantar surface contact area, either including or excluding the toe region.

  10. Accuracy and reliability of three-dimensional surface reconstruction measurement

    International Nuclear Information System (INIS)

    Mizukami, Chikashi; Yamamoto, Etsuo; Ohmura, Masaki; Oiki, Hiroyuki; Tsuji, Jun; Muneta, Yuki; Tanabe, Makito; Hakuba, Nobuhiro; Azemoto, Syougo.

    1993-01-01

    We are using a new three-dimensional (3-D) surface reconstruction system to measure the temporal bones. This system offers the advantage of observation of the external aperture of the vestibular aqueduct and the porus acusticus internus in living subjects. However, its accuracy has not been confirmed. To investigate the accuracy of this new system, we measured the length of an in situ ceramic ossicular replacement prosthesis (CORP) of known length of 6.0 mm using 3-D surface reconstruction, conventional plain X-ray and polytomography. The CORP was scanned in the axial, sagittal and oblique directions. The mean measured length obtained with the 3-D surface reconstruction images was 5.94±0.21 on vertical scans, 5.91±0.27 on horizontal scans, and 6.01±0.25 on oblique scans. There were no significant differences among the measured lengths obtained in the three directions. Therefore, this 3-D surface reconstruction measurement system is considered to be reliable. Conversely, the mean measured length obtained by plain X-ray was 7.98±0.20, and by polytomography it was 7.94±0.23. These conventional methods have the inherent disadvantage of magnification of size which consequently requires correction. (author)

  11. Scaling of turbulence spectra measured in strong shear flow near the Earth’s surface

    Science.gov (United States)

    Mikkelsen, T.; Larsen, S. E.; Jørgensen, H. E.; Astrup, P.; Larsén, X. G.

    2017-12-01

    1 in the lowest part of the atmospheric surface layer with the form ∼ {u}* 2{k}-1, where {u}* is the surface friction velocity and k is the wavenumber. Tchen’s turbulence theory is shown to be able to predict the measured spectra of the wind velocity component parallel to the mean wind direction for eddy sizes larger than the measurement height above the ground. An amended analytical model for the near-neutral surface layer spectrum is then proposed. This model, which is applicable to the scaling of the u spectrum at all heights in the surface layer, is obtained by a combination of Kaimal’s classical spectral model for scaling the inertial subrange with Tchen’s 1953 and 1954 proposed shear production subrange theory. The shear production-amended spectral model is compared with observations of ensemble-averaged near-neutral spectra selected during a nine-month measurement period from recordings from six sonic anemometers at heights of 10, 20, 40, 60, 80, and 100 m in the meteorological tower at the test site for large wind turbines in Høvsøre, Denmark. Finally, potential applications of the new spectral model are discussed, in particular for use within the lowest one-third of the surface layer in which the production subrange component of the spectrum is most prominent. The new spectral model can supply wavenumber-resolved turbulent kinetic energies for the prediction of wind loads on buildings, bridges, and wind turbines, and its spectral parameterization can also be used for scale-dependent parameterization of, e.g., surface-released atmospheric dispersion calculations for regions close to the ground.

  12. New procedure to measure simultaneously the surface tension and contact angle.

    Science.gov (United States)

    Champmartin, S; Ambari, A; Le Pommelec, J Y

    2016-05-01

    This paper proposes a new procedure to simultaneously measure the static contact angle and the surface tension of a liquid using a spherical geometry. Unlike the other existing methods, the knowledge of one of both previous parameters and the displacement of the sphere are not mandatory. The technique is based on the measurement of two simple physical quantities: the height of the meniscus formed on a sphere at the very contact with a liquid bath and the resulting vertical force exerted on this object at equilibrium. The meniscus height, whose exact value requires the numerical resolution of the Laplace equation, is often estimated with an approximate 2D model, valid only for very large spheres compared to the capillary length. We develop instead another simplified solution of the Young-Laplace equation based on the work of Ferguson for the meniscus on a cylinder and adapted for the spherical shape. This alternative model, which is less restrictive in terms of the sphere size, is successfully compared to numerical solutions of the complete Young-Laplace equation. It appears to be accurate for sphere radii larger than only two capillary lengths. Finally the feasibility of the method is experimentally tested and validated for three common liquids and two "small" steel spheres.

  13. Surface temperature measurement of plasma facing components in tokamaks

    International Nuclear Information System (INIS)

    Amiel, Stephane

    2014-01-01

    During this PhD, the challenges on the non-intrusive surface temperature measurements of metallic plasma facing components in tokamaks are reported. Indeed, a precise material emissivity value is needed for classical infrared methods and the environment contribution has to be known particularly for low emissivities materials. Although methods have been developed to overcome these issues, they have been implemented solely for dedicated experiments. In any case, none of these methods are suitable for surface temperature measurement in tokamaks.The active pyrometry introduced in this study allows surface temperature measurements independently of reflected flux and emissivities using pulsed and modulated photothermal effect. This method has been validated in laboratory on metallic materials with reflected fluxes for pulsed and modulated modes. This experimental validation is coupled with a surface temperature variation induced by photothermal effect and temporal signal evolvement modelling in order to optimize both the heating source characteristics and the data acquisition and treatment. The experimental results have been used to determine the application range in temperature and detection wavelengths. In this context, the design of an active pyrometry system on tokamak has been completed, based on a bicolor camera for a thermography application in metallic (or low emissivity) environment.The active pyrometry method introduced in this study is a complementary technique of classical infrared methods used for thermography in tokamak environment which allows performing local and 2D surface temperature measurements independently of reflected fluxes and emissivities. (author) [fr

  14. Direct measurement of Cu surface self-diffusion on a checked surface

    International Nuclear Information System (INIS)

    Cousty, Jacques; Peix, Roger; Perraillon, Bernard.

    1976-01-01

    A radiotracer technique ( 64 Cu) was developed to measure surface diffusion on copper surfaces of total impurity concentration not exceeding some 10 -3 monolayers. The apparatus used consists of a slow electron diffraction device, an Auger analysis spectrometer (CMA), an ion gun and an evaporation device assembled in an ultra-vacuum chamber holding a residual pressure below 10 -10 Torr. A sample handler enables the surface studied to be positioned in front of each of these instruments. During the diffusion treatment the chemical composition of the surface is checked intermittently, and afterwards the spread of the deposit is measured outside the ultravacuum chamber. Slices several microns thick are removed and dissolved separately in dishes containing HNO 3 . The activity is then measured with a flow counter [fr

  15. Evaluation of Satellite-Based Surface Energy Budget Products with Surface Measurements Over the Great Lakes

    Science.gov (United States)

    Wang, H.; Loeb, N. G.; Lenters, J. D.; Spence, C.; Blanken, P.

    2017-12-01

    Earth's climate is fundamentally driven by the global energy balance. While Earth's energy budget at the top-of-atmosphere (TOA) is well understood, satellite-based estimates of the global mean surface energy budget yield an imbalance of 15-20 Wm-2. The data products used to infer the components of the surface energy budget are often based upon physical or empirical models and ancillary input data sets of varying quality. In order to make progress, comparisons between satellite-based estimates of the surface energy budget components and direct surface measurements are critically needed. This study evaluates surface radiative fluxes from NASA CERES EBAF and surface turbulent heat fluxes from OAFLUX by comparing them with surface station measurements from the Great Lakes Evaporation Network (GLEN). The GLEN measurements are collected using instruments on lighthouses in the Great Lakes, and include surface evaporation measurement via eddy covariance technique. The evaluation is performed for 3 offshore and 1 nearshore Great Lakes sites. We highlight results for Stannard Rock in Lake Superior, which is the farthest lighthouse from shore ( 40km from the nearest land). Relative to the GLEN observations, the OAFLUX underestimates latent heat flux by 12 Wm-2 (19 Wm-2) at Stannard Rock (4-station average), in part due to its weaker near surface wind speed, and overestimates sensible heat flux by 12 Wm-2 (6 Wm-2), which is partly contributed by its colder surface air temperature. The CERES EBAF-Surface overestimates the surface downward all-sky shortwave (longwave) flux by 8 Wm-2 (7 Wm-2) at Stannard Rock, and is comparable to the 4-station average. As a result, the surface estimated using EBAF-Surface and OAFLUX receives 16 Wm-2 (13 Wm-2) more than the GLEN observations at Stannard Rock (4-station average). The above surface energy flux differences will be further discussed based on a comparison between the input data sets used in the satellite-based estimates and

  16. Measuring surface flow velocity with smartphones: potential for citizen observatories

    Science.gov (United States)

    Weijs, Steven V.; Chen, Zichong; Brauchli, Tristan; Huwald, Hendrik

    2014-05-01

    Stream flow velocity is an important variable for discharge estimation and research on sediment dynamics. Given the influence of the latter on rating curves (stage-discharge relations), and the relative scarcity of direct streamflow measurements, surface velocity measurements can offer important information for, e.g., flood warning, hydropower, and hydrological science and engineering in general. With the growing amount of sensing and computing power in the hands of more outdoorsy individuals, and the advances in image processing techniques, there is now a tremendous potential to obtain hydrologically relevant data from motivated citizens. This is the main focus of the interdisciplinary "WeSenseIt" project, a citizen observatory of water. In this subproject, we investigate the feasibility of stream flow surface velocity measurements from movie clips taken by (smartphone-) cameras. First results from movie-clip derived velocity information will be shown and compared to reference measurements.

  17. Topography measurements for determining the decay factors in surface replication

    International Nuclear Information System (INIS)

    Song, J; Zheng, A; Vorburger, T V; Rubert, P

    2008-01-01

    The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

  18. Measurement of surface crack length using image processing technology

    International Nuclear Information System (INIS)

    Nahm, Seung Hoon; Kim, Si Cheon; Kim, Yong Il; Ryu, Dae Hyun

    2001-01-01

    The development of a new experimental method is required to easily observe the growth behavior of fatigue cracks. To satisfy the requirement, an image processing technique was introduced to fatigue testing. The length of surface fatigue crack could be successfully measured by the image processing system. At first, the image data of cracks were stored into the computer while the cyclic loading was interrupted. After testing, crack length was determined using image processing software which was developed by ourselves. Block matching method was applied to the detection of surface fatigue cracks. By comparing the data measured by image processing system with the data measured by manual measurement with a microscope, the effectiveness of the image processing system was established. If the proposed method is used to monitor and observe the crack growth behavior automatically, the time and efforts for fatigue test could be dramatically reduced

  19. Two-pulse rapid remote surface contamination measurement.

    Energy Technology Data Exchange (ETDEWEB)

    Headrick, Jeffrey M.; Kulp, Thomas J.; Bisson, Scott E.; Reichardt, Thomas A.; Farrow, Roger L.

    2010-11-01

    This project demonstrated the feasibility of a 'pump-probe' optical detection method for standoff sensing of chemicals on surfaces. Such a measurement uses two optical pulses - one to remove the analyte (or a fragment of it) from the surface and the second to sense the removed material. As a particular example, this project targeted photofragmentation laser-induced fluorescence (PF-LIF) to detect of surface deposits of low-volatility chemical warfare agents (LVAs). Feasibility was demonstrated for four agent surrogates on eight realistic surfaces. Its sensitivity was established for measurements on concrete and aluminum. Extrapolations were made to demonstrate relevance to the needs of outside users. Several aspects of the surface PF-LIF physical mechanism were investigated and compared to that of vapor-phase measurements. The use of PF-LIF as a rapid screening tool to 'cue' more specific sensors was recommended. Its sensitivity was compared to that of Raman spectroscopy, which is both a potential 'confirmer' of PF-LIF 'hits' and is also a competing screening technology.

  20. Surface Roughness Measurement on a Wing Aircraft by Speckle Correlation

    Directory of Open Access Journals (Sweden)

    Alberto Barrientos

    2013-09-01

    Full Text Available The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given.

  1. Surface roughness measurement on a wing aircraft by speckle correlation.

    Science.gov (United States)

    Salazar, Félix; Barrientos, Alberto

    2013-09-05

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given.

  2. Surface photovoltage measurements and finite element modeling of SAW devices.

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Christine

    2012-03-01

    Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.

  3. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...... the catalytic surface through the annulus between the tubes, and the gas is sampled close to the surface by the capillary. The influence of various design parameters on the lateral resolution and sensitivity of the measurements is investigated. It is found that the cuter diameter of the annulus sets the upper......, the limits of the range in reaction rate, which can be Studied are estimated. (c) 2005 Elsevier B.V. All rights reserved....

  4. Acoustics and Surface Pressure Measurements from Tandem Cylinder Configurations

    Science.gov (United States)

    Hutcheson, Florence V.; Brooks, Thomas F.; Lockard, David P.; Choudhari, Meelan M.; Stead, Daniel J.

    2014-01-01

    Acoustic and unsteady surface pressure measurements from two cylinders in tandem configurations were acquired to study the effect of spacing, surface trip and freestream velocity on the radiated noise. The Reynolds number ranged from 1.15x10(exp 5) to 2.17x10(exp 5), and the cylinder spacing varied between 1.435 and 3.7 cylinder diameters. The acoustic and surface pressure spectral characteristics associated with the different flow regimes produced by the cylinders' wake interference were identified. The dependence of the Strouhal number, peak Sound Pressure Level and spanwise coherence on cylinder spacing and flow velocity was examined. Directivity measurements were performed to determine how well the dipole assumption for the radiation of vortex shedding noise holds for the largest and smallest cylinder spacing tested.

  5. Freeform surface measurement and characterisation using a toolmakers microscope

    International Nuclear Information System (INIS)

    Wong, Francis Seung-yin; Chauh, Kong-Bieng; Venuvinod, Patri K

    2014-01-01

    Current freeform surface (FFS) characterization systems mainly cover aspects related to computer-aided design/manufacture (CAD/CAM). This paper describes a new approach that extends into computer-aided inspection (CAI).The following novel features are addressed: - ◼ Feature recognition and extraction from surface data; - ◼ Characterisation of properties of the surface's M and N vectors at individual vertex; - ◼ Development of a measuring plan using a toolmakers microscope for the inspection of the FFS; - ◼ Inspection of the actual FFS produced by CNC milling; - ◼ Verification of the measurement results and comparison with the CAD design data; Tests have shown that the deviations between the CAI and CAD data were within the estimated uncertainty limits

  6. Development of measurement standards for verifying functional performance of surface texture measuring instruments

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, A [Life and Industrial Product Development Department Olympus Corporation, 2951 Ishikawa-machi, Hachiouji-shi, Tokyo (Japan); Suzuki, H [Industrial Marketing and Planning Department Olympus Corporation, Shinjyuku Monolith, 3-1 Nishi-Shinjyuku 2-chome, Tokyo (Japan); Yanagi, K, E-mail: a_fujii@ot.olympus.co.jp [Department of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka-machi, Nagaoka-shi, Niigata (Japan)

    2011-08-19

    A new measurement standard is proposed for verifying overall functional performance of surface texture measuring instruments. Its surface is composed of sinusoidal surface waveforms of chirp signals along horizontal cross sections of the material measure. One of the notable features is that the amplitude of each cycle in the chirp signal form is geometrically modulated so that the maximum slope is kept constant. The maximum slope of the chirp-like signal is gradually decreased according to movement in the lateral direction. We fabricated the measurement standard by FIB processing, and it was calibrated by AFM. We tried to evaluate the functional performance of Laser Scanning Microscope by this standard in terms of amplitude response with varying slope angles. As a result, it was concluded that the proposed standard can easily evaluate the performance of surface texture measuring instruments.

  7. Silicon surface barrier detectors used for liquid hydrogen density measurement

    Science.gov (United States)

    James, D. T.; Milam, J. K.; Winslett, H. B.

    1968-01-01

    Multichannel system employing a radioisotope radiation source, strontium-90, radiation detector, and a silicon surface barrier detector, measures the local density of liquid hydrogen at various levels in a storage tank. The instrument contains electronic equipment for collecting the density information, and a data handling system for processing this information.

  8. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    Road surface reflection data in the form of standard r-tables serve as input for design calculations of road lighting installations on traffic roads. However, in several countries the use of the standard r-tables has not been verified by measurement in a long period of time, while the types of road...

  9. 3D Surface Temperature Measurement of Plant Canopies Using Photogrammetry Techniques From A UAV.

    Science.gov (United States)

    Irvine, M.; Lagouarde, J. P.

    2017-12-01

    Surface temperature of plant canopies and within canopies results from the coupling of radiative and energy exchanges processes which govern the fluxes at the interface soil-plant-atmosphere. As a key parameter, surface temperature permits the estimation of canopy exchanges using processes based modeling methods. However detailed 3D surface temperature measurements or even profile surface temperature measurements are rarely made as they have inherent difficulties. Such measurements would greatly improve multi-level canopy models such as NOAH (Chen and Dudhia 2001) or MuSICA (Ogée and Brunet 2002, Ogée et al 2003) where key surface temperature estimations, at present, are not tested. Additionally, at larger scales, canopy structure greatly influences satellite based surface temperature measurements as the structure impacts the observations which are intrinsically made at varying satellite viewing angles and solar heights. In order to account for these differences, again accurate modeling is required such as through the above mentioned multi-layer models or with several source type models such as SCOPE (Van der Tol 2009) in order to standardize observations. As before, in order to validate these models, detailed field observations are required. With the need for detailed surface temperature observations in mind we have planned a series of experiments over non-dense plant canopies to investigate the use of photogrammetry techniques. Photogrammetry is normally used for visible wavelengths to produce 3D images using cloud point reconstruction of aerial images (for example Dandois and Ellis, 2010, 2013 over a forest). From these cloud point models it should be possible to establish 3D plant surface temperature images when using thermal infrared array sensors. In order to do this our experiments are based on the use of a thermal Infrared camera embarked on a UAV. We adapt standard photogrammetry to account for limits imposed by thermal imaginary, especially the low

  10. Replacing orthometric heights with ellipsoidal heights in ...

    African Journals Online (AJOL)

    Differential Global Positioning System (DGPS) is one of the most frequently used positioning methods in geodesy. The end products of surveying with Global Navigation Satellite Systems (GNSS)are geodetic latitude (ϕ), geodetic longitude (λ) and ellipsoidal height (h) which are obtained with reference to the ellipsoid.

  11. A new approach of surface flux measurements using DTS

    Science.gov (United States)

    van Emmerik, T. H. M.; Wenker, K. J. R.; Rimmer, A.; de Jong, S. A. P.; Lechinsky, Y.; van de Giesen, N. C.

    2012-04-01

    Estimation of surface fluxes is a difficult task, especially over lakes. Determining latent heat flux (evaporation), sensible heat flux and ground heat flux involves measurements and (or calculations) of net radiation, air temperature, water temperature, wind speed and relative humidity. This research presents a new method to measure surface fluxes by means of Distributed Temperature Sensing (DTS). From 0.5 m above lake level to 1.5 m under lake level DTS was applied to measure temperature. Using a PVC hyperboloid construction, a floating standalone measuring device was developed. This new setup distinguished itself by the open construction, so it is almost insensitive to direct radiation. While most of the lake ground heat changes occur very close to the lake surface, most measuring methods only obtain rough results. With this construction it was possible to create a spiral shaped fiber-optic cable setup, with which a vertical spatial resolution of 0.02 m and a temporal resolution of 1 min was obtained. The new method was tested in the deep Lake Kinneret (Israel) from 6 October, 2011 to 11 October, 2011and in the shallow Lake Binaba (Ghana) from 24 October, 2011 to 28 October, 2011. This study shows that with the developed method it is possible to capture the energy fluxes within the top water layer with a high resolution. When the old low resolution method was compared with the new high resolution method, it could be concluded that the impact of the surface fluxes in the upper layer is high on the energy balance on a daily scale. During the measuring period it was possible to use the temperature measured by the DTS to determine the sensible heat flux, the latent heat flux and the ground heat flux of both lakes.

  12. Estimation of surface area and surface area measure of three-dimensional sets from digitizations

    DEFF Research Database (Denmark)

    Ziegel, Johanna; Kiderlen, Markus

    2010-01-01

    A local method for estimating surface area and surface area measure of three-dimensional objects from discrete binary images is presented. A weight is assigned to each 2 × 2 × 2 configuration of voxels and the total surface area of an object is given by summation of the local area contributions....... The method is based on an exact asymptotic result that holds for increasing resolution of the digitization. It states that the number of occurrences of a 2 ×  2 × 2 configuration is asymptotically proportional to an integral of its “h-function” with respect to the surface area measure of the object. We find...

  13. Facial width-to-height ratio predicts self-reported dominance and aggression in males and females, but a measure of masculinity does not.

    Science.gov (United States)

    Lefevre, Carmen E; Etchells, Peter J; Howell, Emma C; Clark, Andrew P; Penton-Voak, Ian S

    2014-10-01

    Recently, associations between facial structure and aggressive behaviour have been reported. Specifically, the facial width-to-height ratio (fWHR) is thought to link to aggression, although it is unclear whether this association is related to a specific dimension of aggression, or to a more generalized concept of dominance behaviour. Similarly, an association has been proposed between facial masculinity and dominant and aggressive behaviour, but, to date, this has not been formally tested. Because masculinity and fWHR are negatively correlated, it is unlikely that both signal similar behaviours. Here, we thus tested these associations and show that: (i) fWHR is related to both self-reported dominance and aggression; (ii) physical aggression, verbal aggression and anger, but not hostility are associated with fWHR; (iii) there is no evidence for a sex difference in associations between fWHR and aggression; and (iv) the facial masculinity index does not predict dominance or aggression. Taken together, these results indicate that fWHR, but not a measure of facial masculinity, cues dominance and specific types of aggression in both sexes. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  14. Drag resistance measurements for newly applied antifouling coatings and welding seams on ship hull surface

    DEFF Research Database (Denmark)

    Wang, Xueting; Olsen, S. M.; Andres, E.

    in their newly applied conditions. The effects of water absorption of newly applied antifouling coatings on frictional resistance were measured. A flexible rotor with artificial welding seams on its periphery has been designed and constructed to estimate the influence of welding seams on drag resistance. Both......Drag resistances of newly applied antifouling coatings and welding seams on ship hull surface have been investigated using a pilot-scale rotary setup. Both conventional biocide-based antifouling (AF) coatings and silicone-based fouling release (FR) coatings have been studied and compared...... the density of welding seams (number per 5 m ship side) and the height of welding seams had a significant effect on drag resistance....

  15. Modelling of Lunar Dust and Electrical Field for Future Lunar Surface Measurements

    Science.gov (United States)

    Lin, Yunlong

    Modelling of the lunar dust and electrical field is important to future human and robotic activities on the surface of the moon. Apollo astronauts had witnessed the maintaining of micron- and millimeter sized moon dust up to meters level while walked on the surface of the moon. The characterizations of the moon dust would enhance not only the scientific understanding of the history of the moon but also the future technology development for the surface operations on the moon. It has been proposed that the maintaining and/or settlement of the small-sized dry dust are related to the size and weight of the dust particles, the level of the surface electrical fields on the moon, and the impaction and interaction between lunar regolith and the solar particles. The moon dust distributions and settlements obviously affected the safety of long term operations of future lunar facilities. For the modelling of the lunar dust and the electrical field, we analyzed the imaging of the legs of the moon lander, the cover and the footwear of the space suits, and the envelope of the lunar mobiles, and estimated the size and charges associated with the small moon dust particles, the gravity and charging effects to them along with the lunar surface environment. We also did numerical simulation of the surface electrical fields due to the impaction of the solar winds in several conditions. The results showed that the maintaining of meters height of the micron size of moon dust is well related to the electrical field and the solar angle variations, as expected. These results could be verified and validated through future on site and/or remote sensing measurements and observations of the moon dust and the surface electrical field.

  16. Analysis of flame surface density measurements in turbulent premixed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Halter, Fabien [Institut PRISME, Universite d' Orleans, 45072 Orleans (France); Chauveau, Christian; Goekalp, Iskender [Institut de Combustion, Aerothermique, Reactivite et Environnement, Centre National de la Recherche Scientifique, 45071 Orleans (France); Veynante, Denis [Laboratoire E.M2.C, Centre National de la Recherche Scientifique, Ecole Centrale Paris, 92295 Chatenay-Malabry (France)

    2009-03-15

    In premixed turbulent combustion, reaction rates can be estimated from the flame surface density. This parameter, which measures the mean flame surface area available per unit volume, may be obtained from algebraic expressions or by solving a transport equation. In this study, detailed measurements were performed on a Bunsen-type burner fed with methane/air mixtures in order to determine the local flame surface density experimentally. This burner, located in a high-pressure combustion chamber, allows investigation of turbulent premixed flames under various flow, mixture, and pressure conditions. In the present work, equivalence ratio was varied from 0.6 to 0.8 and pressure from 0.1 to 0.9 MPa. Flame front visualizations by Mie scattering laser tomography are used to obtain experimental data on the instantaneous flame front dynamics. The exact equation given by Pope is used to obtain flame surface density maps for different flame conditions. Some assumptions are made in order to access three-dimensional information from our two-dimensional experiments. Two different methodologies are proposed and tested in term of global mass balance (what enters compared to what is burned). The detailed experimental flame surface data provided for the first time in this work should progressively allow improvement of turbulent premixed flame modeling approaches. (author)

  17. NOTE: Surface dose extrapolation measurements with radiographic film

    Science.gov (United States)

    Butson, Martin J.; Cheung, Tsang; Yu, Peter K. N.; Currie, Michael

    2004-07-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size.

  18. Key techniques for vision measurement of 3D object surface

    Science.gov (United States)

    Yang, Huachao; Zhang, Shubi; Guo, Guangli; Liu, Chao; Yu, Ruipeng

    2006-11-01

    Digital close-range photogrammetry system and machine vision are widely used in production control, quality inspection. The main aim is to provide accurate 3D objects or reconstruction of an object surface and give an expression to an object shape. First, the key techniques of camera calibration and target image positioning for 3D object surface vision measurement were briefly reviewed and analyzed in this paper. Then, an innovative and effect method for precise space coordinates measurements was proposed. Test research proved that the thought and methods we proposed about image segmentation, detection and positioning of circular marks were effective and valid. A propriety weight value for adding parameters, control points and orientation elements in bundle adjustment with self-calibration are advantageous to gaining high accuracy of space coordinates. The RMS error of check points is less than +/-1 mm, which can meet the requirement in industrial measurement with high accuracy.

  19. Combined surface acoustic wave and surface plasmon resonance measurement of collagen and fibrinogen layer physical properties

    Directory of Open Access Journals (Sweden)

    J.-M. Friedt

    2016-12-01

    Full Text Available We use an instrument combining optical (surface plasmon resonance and acoustic (Love mode surface acoustic wave device real-time measurements on a same surface for the identification of water content in collagen and fibrinogen protein layers. After calibration of the surface acoustic wave device sensitivity by copper electrodeposition and surfactant adsorption, the bound mass and its physical properties – density and optical index – are extracted from the complementary measurement techniques and lead to thickness and water ratio values compatible with the observed signal shifts. Such results are especially usefully for protein layers with a high water content as shown here for collagen on an hydrophobic surface. We obtain the following results: collagen layers include 70±20% water and are 16±3 to 19±3 nm thick for bulk concentrations ranging from 30 to 300 μg/ml. Fibrinogen layers include 50±10% water for layer thicknesses in the 6±1.5 to 13±2 nm range when the bulk concentration is in the 46 to 460 μg/ml range. Keywords: surface acoustic wave, surface plasmon resonance, collagen, fibrinogen, density, thickness

  20. An experimental method for making spectral emittance and surface temperature measurements of opaque surfaces

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Daniel Maynes, R.; Baxter, Larry L.

    2011-01-01

    An experimental procedure has been developed to make spectral emittance and temperature measurements. The spectral emittance of an object is calculated using measurements of the spectral emissive power and of the surface temperature of the object obtained using a Fourier transform infrared (FTIR) spectrometer. A calibration procedure is described in detail which accounts for the temperature dependence of the detector. The methods used to extract the spectral emissive power and surface temperature from measured infrared spectra were validated using a blackbody radiator at known temperatures. The average error in the measured spectral emittance was 2.1% and the average difference between the temperature inferred from the recorded spectra and the temperature indicated on the blackbody radiator was 1.2%. The method was used to measure the spectral emittance of oxidized copper at various temperatures.

  1. A new surface resistance measurement method with ultrahigh sensitivity

    International Nuclear Information System (INIS)

    Liang, Changnian.

    1993-01-01

    A superconducting niobium triaxial cavity has been designed and fabricated to study residual surface resistance of planar superconducting materials. The edge of a 25.4 mm or larger diameter sample in the triaxial cavity is located outside the strong field region. Therefore, the edge effects and possible losses between the thin film and the substrate have been minimized, ensuring that induced RF losses are intrinsic to the test material. The fundamental resonant frequency of the cavity is the same as the working frequency of CEBAF cavities. The cavity has a compact size compared to its TE 011 counterpart, which makes it more sensitive to the sample's loss. For even higher sensitivity, a calorimetry method has been used to measure the RF losses on the superconducting sample. At 2 K, a 2 μK temperature change can be resolved by using carbon resistor sensors. The temperature distribution caused by RF heating is measured by 16 carbon composition resistor sensors. A 0.05 μW heating power can be detected as such a resolution, which translates to a surface resistance of 0.02 nΩ at a surface magnetic field of 52 Oe. This is the most sensitive device for surface resistance measurements to date. In addition, losses due to the indium seal, coupling probes, field emission sites other than the sample, and all of the high field resonator surface, are excluded in the measurement. Surface resistance of both niobium and high-Tc superconducting thin films has been measured. A low R s of 35.2 μΩ was measured for a 25.4 mm diameter YBa 2 Cu 3 O 7 thin film at 1.5 GHz and at 2 K. The measurement result is the first result for a large area epitaxially grown thin film sample at such a low RF frequency. The abrupt disappearance of multipacting between two parallel plates has been observed and monitored with the 16 temperature mapping sensors. Field emission or some field dependent anomalous RF losses on the niobium plate have also been observed

  2. Water Surface and Velocity Measurement-River and Flume

    Directory of Open Access Journals (Sweden)

    J. H. Chandler

    2014-06-01

    Full Text Available Understanding the flow of water in natural watercourses has become increasingly important as climate change increases the incidence of extreme rainfall events which cause flooding. Vegetation in rivers and streams reduce water conveyance and natural vegetation plays a critical role in flood events which needs to be understood more fully. A funded project at Loughborough University is therefore examining the influence of vegetation upon water flow, requiring measurement of both the 3-D water surface and flow velocities. Experimental work therefore requires the measurement of water surface morphology and velocity (i.e. speed and direction in a controlled laboratory environment using a flume but also needs to be adaptable to work in a real river. Measuring the 3D topographic characteristics and velocity field of a flowing water surface is difficult and the purpose of this paper is to describe recent experimental work to achieve this. After reviewing past work in this area, the use of close range digital photogrammetry for capturing both the 3D water surface and surface velocity is described. The selected approach uses either two or three synchronised digital SLR cameras in combination with PhotoModeler for data processing, a commercial close range photogrammetric package. One critical aspect is the selection and distribution of appropriate floating marker points, which are critical if automated and appropriate measurement methods are to be used. Two distinct targeting approaches are available: either large and distinct specific floating markers or some fine material capable of providing appropriate texture. Initial work described in this paper uses specific marker points, which also provide the potential measuring surface velocity. The paper demonstrates that a high degree of measurement and marking automation is possible in a flume environment, where lighting influences can be highly controlled. When applied to a real river it is apparent that

  3. Simultaneous measurements of top surface and its underlying film surfaces in multilayer film structure.

    Science.gov (United States)

    Ghim, Young-Sik; Rhee, Hyug-Gyo; Davies, Angela

    2017-09-19

    With the growth of 3D packaging technology and the development of flexible, transparent electrodes, the use of multilayer thin-films is steadily increasing throughout high-tech industries including semiconductor, flat panel display, and solar photovoltaic industries. Also, this in turn leads to an increase in industrial demands for inspection of internal analysis. However, there still remain many technical limitations to overcome for measurement of the internal structure of the specimen without damage. In this paper, we propose an innovative optical inspection technique for simultaneous measurements of the surface and film thickness corresponding to each layer of multilayer film structures by computing the phase and reflectance over a wide range of wavelengths. For verification of our proposed method, the sample specimen of multilayer films was fabricated via photolithography process, and the surface profile and film thickness of each layer were measured by two different techniques of a stylus profilometer and an ellipsometer, respectively. Comparison results shows that our proposed technique enables simultaneous measurements of the top surface and its underlying film surfaces with high precision, which could not be measured by conventional non-destructive methods.

  4. Tree Height Calculator: An Android App for Estimating Tree Height

    Science.gov (United States)

    Burca, V. S.; Htet, N. M.; Huang, X.; de Lanerolle, T. R.; Morelli, R.; Gourley, J. R.

    2011-12-01

    Conventionally, measuring tree height requires a collection of different tools - clinometer, transit, pencil, paper, laptop computer. Results are recorded manually and entered into a spreadsheet or database for future calculation and analysis. Tree Height Calculator is a mobile Android app the integrates the various steps in this process thereby improving the accuracy and dramatically reducing the time required to go from taking measurements to analyzing data. Given the user's height and the distance from the base of the tree (which can be downloaded into the app from a server), the app uses the phone's orientation sensor to calculate the angle of elevation. A simple trigonometric formula is then used to calculate and record the tree's height in the phone's database. When the phone has a WiFi connection, the data are transmitted to a server, from where they can be downloaded directly into a spreadsheet. The application was first tested in an Environmental Science laboratory at Trinity College. On the first trial, 103 data samples were collected, stored, and uploaded to the online database with only couple of dropped data points. On the second trial, 98 data samples were gathered with no loss of data. The app combined the individual measurements taken by the students in the lab, reducing the time required to produce a graph of the class's results from days to hours.

  5. Hydrologic Science and Satellite Measurements of Surface Water (Invited)

    Science.gov (United States)

    Alsdorf, D. E.; Mognard, N. M.; Lettenmaier, D. P.

    2010-12-01

    While significant advances continue to be made for satellite measurements of surface waters, important science and application opportunities remain. Examples include the following: (1) Our current methods of measuring floodwater dynamics are either sparsely distributed or temporally inadequate. As an example, flood depths are measured by using high water marks, which capture only the peak of the flood wave, not its temporal variability. (2) Discharge is well measured at individual points along stream networks using in-situ gauges, but these do not capture within-reach hydraulic variability such as the water surface slope changes on the rising and falling limbs of flood waves. (3) Just a 1.0 mm/day error in ET over the Congo Basin translates to a 35,000 m3/s discharge error. Knowing the discharge of the Congo River and its many tributaries should significantly improve our understanding of the water balance throughout the basin. The Congo is exemplary of many other basins around the globe. (4) Arctic hydrology is punctuated by millions of unmeasured lakes. Globally, there might be as many as 30 million lakes larger than a hectare. Storage changes in these lakes are nearly unknown, but in the Arctic such changes are likely an indication of global warming. (5) Well over 100 rivers cross international boundaries, yet the sharing of water data is poor. Overcoming this helps to better manage the entire river basin while also providing a better assessment of potential water related disasters. The Surface Water and Ocean Topography (SWOT, http://swot.jpl.nasa.gov/) mission is designed to meet these needs by providing global measurements of surface water hydrodynamics. SWOT will allow estimates of discharge in rivers wider than 100m (50m goal) and storage changes in water bodies larger than 250m by 250m (and likely as small as one hectare).

  6. Magnetic flux surface measurements at the Wendelstein 7-X stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Otte, Matthias; Andreeva, Tamara; Biedermann, Christoph; Bozhenkov, Sergey; Geiger, Joachim; Sunn Pedersen, Thomas [Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany); Lazerson, Samuel [Princeton Plasma Physics Laboratory, Princeton (United States)

    2016-07-01

    Recently the first plasma operation phase of the Wendelstein 7-X stellarator has been started at IPP Greifswald. Wendelstein 7-X is an optimized stellarator with a complex superconducting magnet system consisting of 50 non-planar and 20 planar field coils and further 10 normal conducting control and 5 trim coils. The magnetic confinement and hence the expected plasma performance are decisively determined by the properties of the magnet system, especially by the existence and quality of the magnetic flux surfaces. Even small error fields may result in significant changes of the flux surface topology. Therefore, measurements of the vacuum magnetic flux surfaces have been performed before plasma operation. The first experimental results confirm the existence and quality of the flux surfaces to the full extend from low field up to the nominal field strength of B=2.5T. This includes the dedicated magnetic limiter configuration that is exclusively used for the first plasma operation. Furthermore, the measurements are indicating that the intrinsic error fields are within the tolerable range and can be controlled utilizing the trim coils as expected.

  7. Surface albedo measurements in Mexico City metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Castro, T; Mar, B; Longoria, R; Ruiz Suarez, L. G [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico); Morales, L [Instituto de Geografia, UNAM, Mexico, D.F. (Mexico)

    2001-04-01

    Optical and thermal properties of soils are important input data for the meteorological and photochemical modules of air quality models. As development of these models increase on spatial resolution good albedo data become more important. In this paper measurements of surface albedo of UV (295-385 nm) and visible (450-550 nm) radiation are reported for different urban and rural surfaces in the vicinity of Mexico City. It was found for the downtown zone and average albedo value of 0.05 which is in very good agreement with reported values for urban surfaces. Our albedo values measured in UV region for grey cement and green grass are of 0.10 and 0.009, respectively, and quite similar to those found at the literature of 0.11 and 0.008 for those type of surfaces. [Spanish] Las propiedades opticas y termicas de suelos son datos importantes para los modulos meteorologicos y fotoquimicos de los modelos de calidad del aire. Conforme aumenta la resolucion espacial del modelo se vuelve mas importante contar con buenos datos de albedo. En este articulo se presentan mediciones de albedo superficial de radiacion Ultravioleta (295-385 nm) y visible (450-550 nm) para diferentes superficies urbanas. Los valores medidos de albedo en la region UV para cemento gris y pasto verde son de 0.10 y 0.009, respectivamente, y son muy similares a los reportados en la literatura, 0.11 y 0.008 para este tipo de superficies.

  8. In defense of the classical height system

    Science.gov (United States)

    Foroughi, Ismael; Vaníček, Petr; Sheng, Michael; Kingdon, Robert William; Santos, Marcelo C.

    2017-11-01

    In many European countries, normal heights referred to the quasi-geoid as introduced by Molodenskij in the mid-20th century are preferred to the classical height system that consists of orthometric heights and the geoid as a reference surface for these heights. The rationale for this choice is supposed to be that in the classical height system, neither the geoid, nor the orthometric height can be ever known with centimetre level accuracy because one would need to know the topographical mass density to a level that can never be achieved. The aim of this paper is to question the validity of this rationale. The common way of assessing the congruency of a local geoid model and the orthometric heights is to compare the geoid heights with the difference between orthometric heights provided by leveling and geodetic heights provided by GNSS. On the other hand, testing the congruency of a quasi-geoidal model with normal height a similar procedure is used, except that instead of orthometric heights, normal heights are employed. For the area of Auvergne, France, which is now a more or less standard choice for precise geoid or quasi-geoid testing, only the normal heights are supplied by the Institute Geographic National, the provider of the data. This is clearly the consequence of the European preference for the Molodenskij system. The quality of the height system is to be judged by the congruency of the difference of the geoid/quasi-geoid heights subtracted from the geodetic heights and orthometric/normal heights. To assess the congruency of the classical height system, the Helmert approximation of orthometric heights is typically used as the transformation between normal and Helmert's heights is easily done. However, the evaluation of the differences between Helmert's and the rigorous orthometric heights is somewhat more involved as will be seen from the review in this paper. For the area of interest, the differences between normal and Helmert's heights at the control

  9. Can atom-surface potential measurements test atomic structure models?

    Science.gov (United States)

    Lonij, Vincent P A; Klauss, Catherine E; Holmgren, William F; Cronin, Alexander D

    2011-06-30

    van der Waals (vdW) atom-surface potentials can be excellent benchmarks for atomic structure calculations. This is especially true if measurements are made with two different types of atoms interacting with the same surface sample. Here we show theoretically how ratios of vdW potential strengths (e.g., C₃(K)/C₃(Na)) depend sensitively on the properties of each atom, yet these ratios are relatively insensitive to properties of the surface. We discuss how C₃ ratios depend on atomic core electrons by using a two-oscillator model to represent the contribution from atomic valence electrons and core electrons separately. We explain why certain pairs of atoms are preferable to study for future experimental tests of atomic structure calculations. A well chosen pair of atoms (e.g., K and Na) will have a C₃ ratio that is insensitive to the permittivity of the surface, whereas a poorly chosen pair (e.g., K and He) will have a ratio of C₃ values that depends more strongly on the permittivity of the surface.

  10. Surface moisture measurement system hardware acceptance test report

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, G.A., Westinghouse Hanford

    1996-05-28

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

  11. System design description for surface moisture measurement system (SMMS)

    Energy Technology Data Exchange (ETDEWEB)

    Vargo, G.F.

    1996-09-23

    The SMMS has been developed to measure moisture in the top few centimeters of tank waste. The SMMS development was initiated by the preliminary findings of SAR-033, and does not necessarily fulfill any established DQO. After the SAR-033 is released, if no significant changes are made, moisture measurements in the organic waste tanks will rapidly become a DQO. The SMMS was designed to be installed in any 4 inch or larger riser, and to allow maximum adjustability for riser lengths, and is used to deploy a sensor package on the waste surface within a 6 foot radius about the azimuth. The first sensor package will be a neutron probe.

  12. Surface moisture measurement system hardware acceptance test procedure

    International Nuclear Information System (INIS)

    Ritter, G.A.

    1996-01-01

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

  13. Actual evaporation estimation from infrared measurement of soil surface temperature

    Directory of Open Access Journals (Sweden)

    Davide Pognant

    2013-09-01

    Full Text Available Within the hydrological cycle, actual evaporation represents the second most important process in terms of volumes of water transported, second only to the precipitation phenomena. Several methods for the estimation of the Ea were proposed by researchers in scientific literature, but the estimation of the Ea from potential evapotranspiration often requires the knowledge of hard-to-find parameters (e.g.: vegetation morphology, vegetation cover, interception of rainfall by the canopy, evaporation from the canopy surface and uptake of water by plant roots and many existing database are characterized by missing or incomplete information that leads to a rough estimation of the actual evaporation amount. Starting from the above considerations, the aim of this study is to develop and validate a method for the estimation of the Ea based on two steps: i the potential evaporation estimation by using the meteorological data (i.e. Penman-Monteith; ii application of a correction factor based on the infrared soil surface temperature measurements. The dataset used in this study were collected during two measurement campaigns conducted both in a plain testing site (Grugliasco, Italy, and in a mountain South-East facing slope (Cogne, Italy. During those periods, hourly measurement of air temperature, wind speed, infrared surface temperature, soil heat flux, and soil water content were collected. Results from the dataset collected in the two testing sites show a good agreement between the proposed method and reference methods used for the Ea estimation.

  14. Holographic otoscope for nanodisplacement measurements of surfaces under dynamic excitation.

    Science.gov (United States)

    Flores-Moreno, J M; Furlong, Cosme; Rosowski, John J; Harrington, Ellery; Cheng, Jeffrey T; Scarpino, C; Santoyo, F Mendoza

    2011-01-01

    We describe a novel holographic otoscope system for measuring nanodisplacements of objects subjected to dynamic excitation. Such measurements are necessary to quantify the mechanical deformation of surfaces in mechanics, acoustics, electronics, biology, and many other fields. In particular, we are interested in measuring the sound-induced motion of biological samples, such as an eardrum. Our holographic otoscope system consists of laser illumination delivery (IS), optical head (OH), and image processing computer (IP) systems. The IS delivers the object beam (OB) and the reference beam (RB) to the OH. The backscattered light coming from the object illuminated by the OB interferes with the RB at the camera sensor plane to be digitally recorded as a hologram. The hologram is processed by the IP using the Fresnel numerical reconstruction algorithm, where the focal plane can be selected freely. Our holographic otoscope system is currently deployed in a clinic, and is packaged in a custom design. It is mounted in a mechatronic positioning system to increase its maneuverability degrees to be conveniently positioned in front of the object to be measured. We present representative results highlighting the versatility of our system to measure deformations of complex elastic surfaces in the wavelength scale including a copper foil membrane and postmortem tympanic membrane. SCANNING 33: 342-352, 2011. © 2011 Wiley Periodicals, Inc. Copyright © 2011 Wiley Periodicals, Inc.

  15. Boundary layer heights and surface fluxes of momentum and heat derived from ECMWF data for use in pollutant dispersion models - problems with data accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Wotawa, G. [Univ. of Agricultural Sciences, Inst. of Meteorology and Physics, Vienna (Austria); Stohl, A. [Ludwig-Maximilians-Univ. Muenchen, Munich (Germany)

    1997-10-01

    Certain boundary layer parameters, especially boundary layer heights, are very important for pollutant dispersion modelling. On the regional scale (>- 100 km), data of the numerical weather prediction model of the European Centre for Medium-Range Weather Forecasts are often used for that purpose. Based on ECMWF data, the meteorological preprocessor FLEXTRA for Lagrangian air quality simulation models and the Lagrangian particle diffusion model FLEXPART have been developed. Using analyses and short term forecasts, a temporal resolution of three hours can be achieved. Some alternative methods to obtain boundary layer parameters can be applied, producing different results which affect all subsequent calculations, for instance the calculation of boundary layer trajectories and the dispersion of air pollutants. (au)

  16. Spatio-temporal evaluation of plant height in corn via unmanned aerial systems

    Science.gov (United States)

    Varela, Sebastian; Assefa, Yared; Vara Prasad, P. V.; Peralta, Nahuel R.; Griffin, Terry W.; Sharda, Ajay; Ferguson, Allison; Ciampitti, Ignacio A.

    2017-07-01

    Detailed spatial and temporal data on plant growth are critical to guide crop management. Conventional methods to determine field plant traits are intensive, time-consuming, expensive, and limited to small areas. The objective of this study was to examine the integration of data collected via unmanned aerial systems (UAS) at critical corn (Zea mays L.) developmental stages for plant height and its relation to plant biomass. The main steps followed in this research were (1) workflow development for an ultrahigh resolution crop surface model (CSM) with the goal of determining plant height (CSM-estimated plant height) using data gathered from the UAS missions; (2) validation of CSM-estimated plant height with ground-truthing plant height (measured plant height); and (3) final estimation of plant biomass via integration of CSM-estimated plant height with ground-truthing stem diameter data. Results indicated a correlation between CSM-estimated plant height and ground-truthing plant height data at two weeks prior to flowering and at flowering stage, but high predictability at the later growth stage. Log-log analysis on the temporal data confirmed that these relationships are stable, presenting equal slopes for both crop stages evaluated. Concluding, data collected from low-altitude and with a low-cost sensor could be useful in estimating plant height.

  17. Measurements of the spatial distribution of tritium in air above a chronically contaminated surface

    International Nuclear Information System (INIS)

    Workman, W.J.G.; Davis, P.A.; Wood, M.J.; Barry, P.J.

    1993-01-01

    Tritium in air (HTO) concentrations were measured over a 13 month period above a surface that is chronically contaminated by tritium-bearing groundwater from a waste management area. The measurements were made using passive diffusion samplers, which were sited at six locations (about 100 m apart) at 0.15, 0.9, and 1.8 m above ground level. The diffusion samplers were compact, sampled at a known rate, and required no external power source. They are ideal for remote locations and require a minimum of effort to collect and analyze the data. HTO-in-air concentration peaked in the summer at 500-1500 Bq.m -3 and decreased in the winter to 1-120 Bq.m -3 . In general, concentration decreased with height above ground level, implying that HTO is being lost from the surface to the atmosphere. The flux of tritium to the atmosphere must, therefore, be taken into account to estimate the tritium mass balance for a contaminated area. (Author) 3 figs., 5 tabs., 10 refs

  18. The evaporative fraction as a measure of surface energy partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, W.E. [Pacific Northwest Lab., Richland, WA (United States); Cuenca, R.H. [Oregon State Univ., Corvallis, OR (United States)

    1990-12-31

    The evaporative fraction is a ratio that expresses the proportion of turbulent flux energy over land surfaces devoted to evaporation and transpiration (evapotranspiration). It has been used to characterize the energy partition over land surfaces and has potential for inferring daily energy balance information based on mid-day remote sensing measurements. The HAPEX-MOBILHY program`s SAMER system provided surface energy balance data over a range of agricultural crops and soil types. The databases from this large-scale field experiment was analyzed for the purpose of studying the behavior and daylight stability of the evaporative fraction in both ideal and general meteorological conditions. Strong linear relations were found to exist between the mid-day evaporative fraction and the daylight mean evaporative fraction. Statistical tests however rejected the hypothesis that the two quantities were equal. The relations between the evaporative fraction and the surface soil moisture as well as soil moisture in the complete vegetation root zone were also explored.

  19. The evaporative fraction as a measure of surface energy partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, W.E. (Pacific Northwest Lab., Richland, WA (United States)); Cuenca, R.H. (Oregon State Univ., Corvallis, OR (United States))

    1990-01-01

    The evaporative fraction is a ratio that expresses the proportion of turbulent flux energy over land surfaces devoted to evaporation and transpiration (evapotranspiration). It has been used to characterize the energy partition over land surfaces and has potential for inferring daily energy balance information based on mid-day remote sensing measurements. The HAPEX-MOBILHY program's SAMER system provided surface energy balance data over a range of agricultural crops and soil types. The databases from this large-scale field experiment was analyzed for the purpose of studying the behavior and daylight stability of the evaporative fraction in both ideal and general meteorological conditions. Strong linear relations were found to exist between the mid-day evaporative fraction and the daylight mean evaporative fraction. Statistical tests however rejected the hypothesis that the two quantities were equal. The relations between the evaporative fraction and the surface soil moisture as well as soil moisture in the complete vegetation root zone were also explored.

  20. Airborne Spectral Measurements of Surface-Atmosphere Anisotropy for Several Surfaces and Ecosystem over Southern Africa

    Science.gov (United States)

    Gatebe, C. K.; King, M. D.; Tsay, S.; Arnold, G. T.; Li, J. Y.

    2001-12-01

    The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft and took measurements on 23 flights between August 15 and September 16. On 12 of those flights, BRF measurements were obtained over different natural surfaces and ecosystem in southern Africa. The BRF measurements were done to characterize surface anisotropy in support of SAFARI 2000 science objectives principally to validate products from NASA's EOS satellites, and to parameterize and validate BRF models. In this paper we present results of BRFs taken over two EOS validation sites: Skukuza tower, South Africa (25.0 oS, 31.5 oE) and Mongu tower, Zambia (15.4 oS, 23.3 oE). Additional sites are also considered and include, Maun tower, Botswana (20.0 oS, 23.5 oE), Sowa Pan, Botswana (20.6 oS, 26.2 oE) and Etosha Pan, Namibia (19.0 oS, 16.0 oE). The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 μ m), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 μ m). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to bank at a comfortable roll angle of ~20 o and fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were

  1. Surface Current Measurements In Terra Nova Bay By Hf Radar

    Science.gov (United States)

    Flocco, D.; Falco, P.; Wadhams, P.; Spezie, G.

    We present the preliminary results of a field experiment carried out within frame- work of the CLIMA project of the Italian National Programme for Antarctic Research (PNRA) and in cooperation with the Scott Polar Research Institute of Cambridge. Dur- ing the second period (02/12/1999-23/01/2000) of the XV Italian expedition a coastal radar was used to characterize the current field in the area of Terra Nova Bay (TNB). One of the aims of the CLIMA (Climatic Long-term Interactions for the Mass balance in Antarctica) project is to determine the role of the polynya in the sea ice mass bal- ance, water structure and local climate. The OSCR-II experiment was planned in order to provide surface current measurements in the area of TNB polynya, one of the most important coastal polynya of the Ross Sea. OSCR (Ocean Surface Current Radar) is a shore based, remote sensing system designed to measure sea surface currents in coastal waters. Two radar sites (a master and a slave) provide with radial current mea- surements; data combined from both sites yield the total current vector. Unfortunately the master and slave stations did not work together throughout the whole period of the experiment. A description of the experiment and a discussion of the results, will be proposed.

  2. Surface temperature measurements of heterogeneous explosives by IR emission

    Energy Technology Data Exchange (ETDEWEB)

    Henson, B.F.; Funk, D.J.; Dickson, P.M.; Fugard, C.S.; Asay, B.W.

    1998-03-01

    The authors present measurements of the integrated IR emission (1--5 {micro}m) from both the heterogeneous explosive PBX 9501 and pure HMX at calibrated temperatures from 300 C to 2,500 C. The IR power emitted as a function of temperature is that expected of a black body, attenuated by a unique temperature independent constant which the authors report as the thermal emissivity. The authors have utilized this calibration of IR emission in measurements of the surface temperature from PBX 9501 subject to 1 GPa, two dimensional impact, and spontaneous ignition in unconfined cookoff. They demonstrate that the measurement of IR emission in this spectral region provides a temperature probe of sufficient sensitivity to resolve the thermal response from the solid explosive throughout the range of weak mechanical perturbation, prolonged heating to ignition, and combustion.

  3. Application of laser tracker technology for measuring optical surfaces

    Science.gov (United States)

    Zobrist, Tom L.

    The pages of this dissertation detail the development of an advanced metrology instrument for measuring large optical surfaces. The system is designed to accurately guide the fabrication of the Giant Magellan Telescope and future telescopes through loose-abrasive grinding. The instrument couples a commercial laser tracker with an advanced calibration technique and a set of external references to mitigate a number of error sources. The system is also required to work as a verification test for the GMT principal optical interferometric test of the polished mirror segment to corroborate the measurements in several low-order aberrations. A set of system performance goals were developed to ensure that the system will achieve these purposes. The design, analysis, calibration results, and measurement performance of the Laser Tracker Plus system are presented in this dissertation.

  4. Measurement of steep aspheric surfaces using an anamorphic probe

    International Nuclear Information System (INIS)

    Biswas, Amiya; Coupland, Jeremy

    2008-01-01

    Synthetic aperture interferometry has been previously proposed as a possible in-process method to measure aspheric form (R. Tomlinson, Appl. Opt.42, 701, 2003.APOPAI0003-693510.1364/AO.42.000701). Preliminary demonstration utilized a scanning probe consisting of a pair of bare single mode fibers to perform source and receive functions. It was found that this probe did not have sufficient numerical aperture (NA) to measure steep surfaces and that simply increasing the NA decreases the light gathering efficiency substantially. In this paper, we introduce supplementary optics to increase the NA, and the light gathering efficiency has been increased by adopting an anamorphic design. A spherical test optic of known form is measured to demonstrate the capability of the new probe design

  5. Measurement of steep aspheric surfaces using an anamorphic probe

    Science.gov (United States)

    Biswas, Amiya; Coupland, Jeremy

    2008-04-01

    Synthetic aperture interferometry has been previously proposed as a possible in-process method to measure aspheric form (R. Tomlinson, Appl. Opt.42, 701, 2003.APOPAI0003-693510.1364/AO.42.000701). Preliminary demonstration utilized a scanning probe consisting of a pair of bare single mode fibers to perform source and receive functions. It was found that this probe did not have sufficient numerical aperture (NA) to measure steep surfaces and that simply increasing the NA decreases the light gathering efficiency substantially. In this paper, we introduce supplementary optics to increase the NA, and the light gathering efficiency has been increased by adopting an anamorphic design. A spherical test optic of known form is measured to demonstrate the capability of the new probe design.

  6. Estimating regional methane surface fluxes: the relative importance of surface and GOSAT mole fraction measurements

    Directory of Open Access Journals (Sweden)

    A. Fraser

    2013-06-01

    Full Text Available We use an ensemble Kalman filter (EnKF, together with the GEOS-Chem chemistry transport model, to estimate regional monthly methane (CH4 fluxes for the period June 2009–December 2010 using proxy dry-air column-averaged mole fractions of methane (XCH4 from GOSAT (Greenhouse gases Observing SATellite and/or NOAA ESRL (Earth System Research Laboratory and CSIRO GASLAB (Global Atmospheric Sampling Laboratory CH4 surface mole fraction measurements. Global posterior estimates using GOSAT and/or surface measurements are between 510–516 Tg yr−1, which is less than, though within the uncertainty of, the prior global flux of 529 ± 25 Tg yr−1. We find larger differences between regional prior and posterior fluxes, with the largest changes in monthly emissions (75 Tg yr−1 occurring in Temperate Eurasia. In non-boreal regions the error reductions for inversions using the GOSAT data are at least three times larger (up to 45% than if only surface data are assimilated, a reflection of the greater spatial coverage of GOSAT, with the two exceptions of latitudes >60° associated with a data filter and over Europe where the surface network adequately describes fluxes on our model spatial and temporal grid. We use CarbonTracker and GEOS-Chem XCO2 model output to investigate model error on quantifying proxy GOSAT XCH4 (involving model XCO2 and inferring methane flux estimates from surface mole fraction data and show similar resulting fluxes, with differences reflecting initial differences in the proxy value. Using a series of observing system simulation experiments (OSSEs we characterize the posterior flux error introduced by non-uniform atmospheric sampling by GOSAT. We show that clear-sky measurements can theoretically reproduce fluxes within 10% of true values, with the exception of tropical regions where, due to a large seasonal cycle in the number of measurements because of clouds and aerosols, fluxes are within 15% of true fluxes. We evaluate our

  7. Measuring and interpreting X-ray fluorescence from planetary surfaces.

    Science.gov (United States)

    Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

    2008-11-15

    As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

  8. Electrical properties of Titan's surface from Cassini RADAR scatterometer measurements

    Science.gov (United States)

    Wye, Lauren C.; Zebker, Howard A.; Ostro, Steven J.; West, Richard D.; Gim, Yonggyu; Lorenz, Ralph D.; The Cassini Radar Team

    2007-06-01

    albedo feature Shangri-La is best fit by a Hagfors model with a dielectric constant close to 2.4 and an rms slope near 9.5°. From the modeled backscatter curves, we find the average radar albedo in the same linear (SL) polarization to be near 0.34. We constrain the total-power albedo in order to compare the measurements with available groundbased radar results, which are typically obtained in both senses of circular polarization. We estimate an upper limit of 0.4 on the total-power albedo, a value that is significantly higher than the 0.21 total albedo value measured at 13 cm [Campbell, D., Black, G., Carter, L., Ostro, S., 2003. Science 302, 431-434]. This is consistent with a surface that has more small-scale structure and is thus more reflective at 2-cm than 13-cm. We compare results across overlapping observations and observe that the reduction and analysis are repeatable and consistent. We also confirm the strong correlations between radar and near-infrared images.

  9. Surface solar irradiance from SCIAMACHY measurements: algorithm and validation

    Directory of Open Access Journals (Sweden)

    P. Wang

    2011-05-01

    Full Text Available Broadband surface solar irradiances (SSI are, for the first time, derived from SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY satellite measurements. The retrieval algorithm, called FRESCO (Fast REtrieval Scheme for Clouds from the Oxygen A band SSI, is similar to the Heliosat method. In contrast to the standard Heliosat method, the cloud index is replaced by the effective cloud fraction derived from the FRESCO cloud algorithm. The MAGIC (Mesoscale Atmospheric Global Irradiance Code algorithm is used to calculate clear-sky SSI. The SCIAMACHY SSI product is validated against globally distributed BSRN (Baseline Surface Radiation Network measurements and compared with ISCCP-FD (International Satellite Cloud Climatology Project Flux Dataset surface shortwave downwelling fluxes (SDF. For one year of data in 2008, the mean difference between the instantaneous SCIAMACHY SSI and the hourly mean BSRN global irradiances is −4 W m−2 (−1 % with a standard deviation of 101 W m−2 (20 %. The mean difference between the globally monthly mean SCIAMACHY SSI and ISCCP-FD SDF is less than −12 W m−2 (−2 % for every month in 2006 and the standard deviation is 62 W m−2 (12 %. The correlation coefficient is 0.93 between SCIAMACHY SSI and BSRN global irradiances and is greater than 0.96 between SCIAMACHY SSI and ISCCP-FD SDF. The evaluation results suggest that the SCIAMACHY SSI product achieves similar mean bias error and root mean square error as the surface solar irradiances derived from polar orbiting satellites with higher spatial resolution.

  10. Retrieving Smoke Aerosol Height from DSCOVR/EPIC

    Science.gov (United States)

    Xu, X.; Wang, J.; Wang, Y.

    2017-12-01

    Unlike industrial pollutant particles that are often confined within the planetary boundary layer, smoke from forest and agriculture fires can inject massive carbonaceous aerosols into the upper troposphere due to the intense pyro-convection. Sensitivity of weather and climate to absorbing carbonaceous aerosols is regulated by the altitude of those aerosol layers. However, aerosol height information remains limited from passive satellite sensors. Here we present an algorithm to estimate smoke aerosol height from radiances in the oxygen A and B bands measured by the Earth Polychromatic Imaging Camera (EPIC) from the Deep Space Climate Observatory (DSCOVR). With a suit of case studies and validation efforts, we demonstrate that smoke aerosol height can be well retrieved over both ocean and land surfaces multiple times daily.

  11. Airborne spectral measurements of surface-atmosphere anisotropy for several surfaces and ecosystems over southern Africa

    Science.gov (United States)

    Gatebe, Charles K.; King, Michael D.; Platnick, Steve; Arnold, G. Thomas; Vermote, Eric F.; Schmid, Beat

    2003-07-01

    The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft during the Southern Africa Regional Science Initiative 2000 (SAFARI 2000) dry season campaign and obtained measurements of bidirectional reflectance distribution function (BRDF) for a variety of natural surfaces and ecosystems in southern Africa. To measure the BRDF of the surface-atmosphere system, the University of Washington CV-580 banked at a roll angle of ˜20° and flew circles about 3 km in diameter above the surface, taking approximately 2 min. Multiple circular orbits were acquired over selected surfaces so that average BRDFs could be acquired, smoothing out small-scale surface and atmospheric inhomogeneities. In this paper, we present results of BRDFs taken over two Earth Observing System (EOS) validation sites: Skukuza tower, South Africa (25.0°S, 31.5°E) and Mongu tower, Zambia (15.4°S, 23.3°E). Additional sites are discussed and include the Maun tower, Botswana (20.0°S, 23.6°E), Sua Pan, Botswana (20.6°S, 25.9°E), Etosha Pan, Namibia (19.0°S, 16.0°E), and marine stratocumulus clouds off the west coast of Namibia (20.5°S, 13.1°E). Results clearly show anisotropy in reflected solar radiation over the various surfaces types: savanna, salt pans, and cloud. The greatest anisotropy is observed over marine stratus clouds, which exhibit strong forward scattering as well as important water cloud scattering features such as the rainbow and glory. The BRDF over savanna is characterized by a distinct backscattering peak in the principal plane and shows directional and spectral variations. Over the pans, the BRDF is more enhanced in the backscattering plane than forward scattering plane and shows little directional variation.

  12. [Measurements of surface ocean carbon dioxide partial pressure during WOCE

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    This paper discusses the research progress of the second year of research under Measurement of Surface Ocean Carbon Dioxide Partial Pressure During WOCE'' and proposes to continue measurements of underway pCO[sub 2]. During most of the first year of this grant, our efforts to measure pCO[sub 2] on WOCE WHP legs were frustrated by ship problems. The R/V Knorr, which was originally scheduled to carry out the first work on WHP lines P19 and P16 in the southeastem Pacific during the 1990-91 austral summer, was delayed in the shipyard during her mid-life refit for more than a year. In the interim, the smaller R/V Thomas Washington, was pressed into service to carry out lower-latitude portions of WHP lines P16 and P17 during mid-1991 (TUNES Expedition). We installed and operated our underway chromatographic system on this expedition, even though space and manpower on this smaller vessel were limited and no one from our group would be aboard any of the 3 WHP expedition legs. The results for carbon dioxide and nitrous oxide are shown. A map of the cruise track is shown for each leg, marked with cumulative distance. Following each track is a figure showing the carbon dioxide and nitrous oxide results as a function of distance along this track. The results are plotted as dry-gas mole fractions (in ppm and ppb, respectively) in air and in gas equilibrated with surface seawater at a total pressure equal to the barometric pressure. The air data are plotted as a 10-point running mean, and appear as a roughly horizontal line. The seawater data are plotted as individual points, using a 5-point Gaussian smoother. Equal values Of xCO[sub 2] in air and surface seawater indicate air-sea equilibrium.

  13. The Measurement and Interpretation of Surface Wave Group Arrival Times

    Science.gov (United States)

    Masters, G.; Kane, D.; Morrow, J.; Zhou, Y.; Tromp, J.

    2005-12-01

    We have recently developed an efficient technique for measuring the relative group arrival times of surface waves by using cross-correlation and cluster analysis of waveform envelope functions. Applying the analysis to minor arc Love and Rayleigh waves in the frequency band 7 to 35 mHz for all events over magnitude 5.5 results in a dataset of over 200,000 measurements at each frequency for long period Rayleigh waves (frequency less than 25 mHz) and about 100,000 measurements at the shorter periods. Analysis of transverse components results in about half as many Love wave measurements. Simple ray theory inversions of the relative arrival times for apparent group velocity produce maps which are accurate representations of the data (often over 90% variance reduction of the relative arrival times) and which show features strongly correlated with tectonics and crustal thickness. The apparent group velocity variations can be extremely large: 30% velocity variations for 20 mHz Rayleigh waves and 40% variations for 30 mHz Rayleigh waves and can have abrupt lateral changes. This raises the concern that non-ray theory effects could be important. Indeed, a recent analysis by Dahlen and Zhou (personal communication) suggests that the group arrival times should be a functions of both the group velocity AND the phase velocity. The simplest way to test the interpretation of the measurements is to perform the analysis on synthetic seismograms computed for a realistic model of the Earth. Here, we use the SEM with a model which incorporates realistic crust and mantle structure. We are currently computing synthetics for a suite of roughly 1000 events recorded globally that extend to a period of 18 seconds. We shall present the results of applying both ray-based and finite frequency inversions to the synthetic data as well as evaluating the effects of off path propagation at short periods using surface wave ray tracing.

  14. Measuring the surface roughness of geological rock surfaces in SAR data using fractal geometry

    Science.gov (United States)

    Ghafouri, Ali; Amini, Jalal; Dehmollaian, Mojtaba; Kavoosi, Mohammad Ali

    2017-05-01

    Determining surface morphology using synthetic aperture radar (SAR) data requires accurate topographic and microtopographic models. To distinguish different surface geometric patterns and to differentiate the formation of geological rock surfaces, it is necessary to model the smoothness and roughness of surfaces based on radar signal backscattering. Euclidean geometry is less able than fractal geometry to describe natural phenomena; however, in application to radar backscattering models, fractal geometry has never fully replaced Euclidean geometry. Using fractal geometry only, this paper attempts to improve the backscattering simulation generated by an Integral Equation Model to improve the description of geological rock surfaces. As the application of radar signal backscattering is a rarity in the domain of geology, the paper also discusses the efficiency of the method in improving the results of conventional geological mapping methods. The proposed method is applied to the Anaran geological formation (between Dehloran and Ilam in IRAN) using TerraSAR-X SAR data and in situ roughness measurements on pure sites with rough, intermediate, and smooth morphologies. This implementation shows fractal and diffractal behavior of geological morphologies under various conditions.

  15. Influence of real and virtual heights on standing balance.

    Science.gov (United States)

    Cleworth, Taylor W; Horslen, Brian C; Carpenter, Mark G

    2012-06-01

    Fear and anxiety induced by threatening scenarios, such as standing on elevated surfaces, have been shown to influence postural control in young adults. There is also a need to understand how postural threat influences postural control in populations with balance deficits and risk of falls. However, safety and feasibility issues limit opportunities to place such populations in physically threatening scenarios. Virtual reality (VR) has successfully been used to simulate threatening environments, although it is unclear whether the same postural changes can be elicited by changes in virtual and real threat conditions. Therefore, the purpose of this study was to compare the effects of real and virtual heights on changes to standing postural control, electrodermal activity (EDA) and psycho-social state. Seventeen subjects stood at low and high heights in both real and virtual environments matched in scale and visual detail. A repeated measures ANOVA revealed increases with height, independent of visual environment, in EDA, anxiety, fear, and center of pressure (COP) frequency, and decreases with height in perceived stability, balance confidence and COP amplitude. Interaction effects were seen for fear and COP mean position; where real elicited larger changes with height than VR. This study demonstrates the utility of VR, as simulated heights resulted in changes to postural, autonomic and psycho-social measures similar to those seen at real heights. As a result, VR may be a useful tool for studying threat related changes in postural control in populations at risk of falls, and to screen and rehabilitate balance deficits associated with fear and anxiety. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Measurement of atmospheric surface layer turbulence using unmanned aerial vehicles

    Science.gov (United States)

    Bailey, Sean; Canter, Caleb

    2017-11-01

    We describe measurements of the turbulence within the atmospheric surface layer using highly instrumented and autonomous unmanned aerial vehicles (UAVs). Results from the CLOUDMAP measurement campaign in Stillwater Oklahoma are presented including turbulence statistics measured during the transition from stably stratified to convective conditions. The measurements were made using pre-fabricated fixed-wing remote-control aircraft adapted to fly autonomously and carry multi-hole pressure probes, pressure, temperature and humidity sensors. Two aircraft were flown simultaneously, with one flying a flight path intended to profile the boundary layer up to 100 m and the other flying at a constant fixed altitude of 50 m. The evolution of various turbulent statistics was determined from these flights, including Reynolds stresses, correlations, spectra and structure functions. These results were compared to those measured by a sonic anemometer located on a 7.5 m tower. This work was supported by the National Science Foundation through Grant #CBET-1351411 and by National Science Foundation award #1539070, Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics (CLOUDMAP).

  17. Reliability of surface EMG measurements from the suprahyoid muscle complex

    DEFF Research Database (Denmark)

    Kothari, Mohit; Stubbs, Peter William; Pedersen, Asger Roer

    2017-01-01

    of using the suprahyoid muscle complex (SMC) using surface electromyography (sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy participants over days. Methods: Seventeen healthy participants were recruited. Measurements were performed twice with one week...... between sessions. Single pulse (at 120% and 140% of the resting motor threshold (rMT)) and paired pulse (2 ms and 15 ms paired pulse) transcranial magnetic stimulation (TMS) were used to elicit MEPs in the SMC which were recorded using sEMG. Results: ≈50% of participants (range: 42%-58%; depending...... on stimulus type/intensity) had significantly different MEP values between day 1 and day 2 for single pulse and paired pulse TMS. A large stimulus artefact resulted in MEP responses that could not be assessed in four participants. Conclusions: The assessment of the SMC using sEMG following TMS was poorly...

  18. Measurement of Tritium Surface Distribution on TFTR Bumper Limiter Tiles

    International Nuclear Information System (INIS)

    Sugiyama, K.; Tanabe, T.; Skinner, C.H.; Gentile, C.A.

    2004-01-01

    The tritium surface distribution on graphite tiles used in the Tokamak Fusion Test Reactor (TFTR) bumper limiter and exposed to TFTR deuterium-tritium (D-T) discharges from 1993 to 1997 was measured by the Tritium Imaging Plate Technique (TIPT). The TFTR bumper limiter shows both re-/co-deposition and erosion. The tritium images for all tiles measured are strongly correlated with erosion and deposition patterns, and long-term tritium retention was found in the re-/co-depositions and flakes. The CFC tiles located at erosion dominated areas clearly showed their woven structure in their tritium images owing to different erosion yields between fibers and matrix. Significantly high tritium retention was observed on all sides of the erosion tiles, indicating carbon transport via repetition of local erosion/deposition cycles

  19. Adult height, nutrition, and population health

    Science.gov (United States)

    Perkins, Jessica M.; Subramanian, S.V.; Davey Smith, George

    2016-01-01

    In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence. PMID:26928678

  20. Measured ground-surface movements, Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Massey, B.L.

    1981-01-01

    The Cerro Prieto geothermal area in the Mexicali Valley, 30 kilometers southeast of Mexicali, Baja California, incurred slight deformation because of the extraction of hot water and steam, and probably, active tectonism. During 1977 to 1978, the US Geological Survey established and measured two networks of horizontal control in an effort to define both types of movement. These networks consisted of: (1) a regional trilateration net brought into the mountain ranges west of the geothermal area from stations on an existing US Geological Survey crustal-strain network north of the international border; and (2) a local net tied to stations in the regional net and encompassing the present and planned geothermal production area. Electronic distance measuring instruments were used to measure the distances between stations in both networks in 1978, 1979 and 1981. Lines in the regional net averaged 25 km. in length and the standard deviation of an individual measurement is estimated to be approx. 0.3 part per million of line length. The local network was measured using different instrumentation and techniques. The average line length was about 5 km. and the standard deviation of an individual measurement approached 3 parts per million per line length. Ground-surface movements in the regional net, as measured by both the 1979 and 1981 resurveys, were small and did not exceed the noise level. The 1979 resurvey of the local net showed an apparent movement of 2 to 3 centimeters inward toward the center of the production area. This apparent movement was restricted to the general limits of the production area. The 1981 resurvey of the local net did not show increased movement attributable to fluid extraction.

  1. Measuring surface energy and evapotranspiration across Caribbean mangrove forests

    Science.gov (United States)

    Lagomasino, D.; Fatoyinbo, T. E.; Price, R.

    2014-12-01

    Coastal mangroves lose large amounts of water through evapotranspiration (ET) that can be equivalent to the amount of annual rainfall in certain years. Satellite remote sensing has been used to estimate surface energy and ET variability in many forested ecosystems, yet has been widely overlooked in mangrove forests. Using a combination of long-term datasets (30-year) acquired from the NASA Landsat 5 and 7 satellite databases, the present study investigated ET and surface energy balance variability between two mangrove forest sites in the Caribbean: 1) Everglades National Park (ENP; Florida, USA) and 2) Sian Ka'an Biosphere Reserve (SKBR; Quintana Roo, Mexico). A satellite-derived surface energy balance model was used to estimate ET in tall and scrub mangroves environments at ENP and SKBR. Results identified significant differences in soil heat flux measurements and ET between the tall and scrub mangrove environments. Scrub mangroves exhibited the highest soil heat flux coincident with the lowest biophysical indices (i.e., Fractional Vegetation Cover, Normalized Difference Vegetation Index, and Soil-Adjusted Vegetation Index) and ET rates. Mangrove damage and mortality was observed on the satellite images following strong tropical storms and associated with anthropogenic modifications and resulted in low values in spectral vegetation indices, higher soil heat flux, and higher ET. Recovery of the spectral characteristics, soil heat flux and ET was within 1-2 years following hurricane disturbance while, degradation caused by human disturbance persisted for many years. Remotely sensed ET of mangrove forests can provide estimates over a few decades and provide us with some understanding of how these environments respond to disturbances to the landscape in periods where no ground data exists or in locations that are difficult to access. Moreover, relationships between energy and water balance components developed for the coastal mangroves of Florida and Mexico could be

  2. Hub Height Ocean Winds over the North Sea Observed by the NORSEWInD Lidar Array: Measuring Techniques, Quality Control and Data Management

    Directory of Open Access Journals (Sweden)

    Matthew Stickland

    2013-09-01

    Full Text Available In the North Sea, an array of wind profiling wind lidars were deployed mainly on offshore platforms. The purpose was to observe free stream winds at hub height. Eight lidars were validated prior to offshore deployment with observations from cup anemometers at 60, 80, 100 and 116 m on an onshore met mast situated in flat terrain. The so-called “NORSEWInD standard” for comparing lidar and mast wind data includes the criteria that the slope of the linear regression should lie within 0.98 and 1.01 and the linear correlation coefficient higher than 0.98 for the wind speed range 4–16 m∙s−1. Five lidars performed excellently, two slightly failed the first criterion and one failed both. The lidars were operated offshore from six months to more than two years and observed in total 107 months of 10-min mean wind profile observations. Four lidars were re-evaluated post deployment with excellent results. The flow distortion around platforms was examined using wind tunnel experiments and computational fluid dynamics and it was found that at 100 m height wind observations by the lidars were not significantly influenced by flow distortion. Observations of the vertical wind profile shear exponent at hub height are presented.

  3. Entrance surface dose measurements in mammography using thermoluminescence technique

    International Nuclear Information System (INIS)

    Rivera, T.; Vega C, H.R.; Manzanares A, E; Azorin, J.; Gonzalez, P.R.

    2007-01-01

    Full text: Of the various techniques that can be used for personnel dosimetry, thermoluminescence dosimetry (TLD) has emerged as a superior technique due to its manifold advantages over other methods of dose estimation. Various phosphors have been therefore investigated regarding their suitability for dosimetry. In this paper, a dosimetry system based on thermally stimulated luminescence (TSL) from zirconium oxide phosphors embedded in polytetrafluorethylene (ZrO 2 +PTFE) was developed for entrance surface doses (ES) measurements in mammography. Small ZrO 2 pellets of 5 mm in diameter and 0.8 mm in thickness were used. The reproducibility of measurements and linearity of ZrO 2 were also studied. The results were compared with those obtained from LiF:Mg,Cu,P usually used for the determination of absorbed dose in mammography. Measurements both per unit air kerma and In vivo were performed using a mammography unit model DMR (General Electric). The results showed that ZrO 2 TLDs can be used for the same X-ray dosimetry applications as LiF:Mg,Cu,P, with each type having the disadvantage of a response dependent on energy, particularly at low energies. These results indicate a considerable potential for use in routine control and In vivo ES measurements in mammography. (Author)

  4. and the CMJ jump height

    Directory of Open Access Journals (Sweden)

    Struzik Artur

    2016-04-01

    Full Text Available Study aim: The elastic potential energy accumulated in the musculotendinous units during the countermovement phase of a jump adds up to the energy supplied by the contracting muscles used in the take-off phase. Consequently, the total mechanical energy used during the jump may reach higher values. Stiffness represents a quantitative measure of a body’s elastic properties. Therefore, the aim of this study was to establish the relationship between leg stiffness and the countermovement jump height.

  5. Accurate fluid force measurement based on control surface integration

    Science.gov (United States)

    Lentink, David

    2018-01-01

    Nonintrusive 3D fluid force measurements are still challenging to conduct accurately for freely moving animals, vehicles, and deforming objects. Two techniques, 3D particle image velocimetry (PIV) and a new technique, the aerodynamic force platform (AFP), address this. Both rely on the control volume integral for momentum; whereas PIV requires numerical integration of flow fields, the AFP performs the integration mechanically based on rigid walls that form the control surface. The accuracy of both PIV and AFP measurements based on the control surface integration is thought to hinge on determining the unsteady body force associated with the acceleration of the volume of displaced fluid. Here, I introduce a set of non-dimensional error ratios to show which fluid and body parameters make the error negligible. The unsteady body force is insignificant in all conditions where the average density of the body is much greater than the density of the fluid, e.g., in gas. Whenever a strongly deforming body experiences significant buoyancy and acceleration, the error is significant. Remarkably, this error can be entirely corrected for with an exact factor provided that the body has a sufficiently homogenous density or acceleration distribution, which is common in liquids. The correction factor for omitting the unsteady body force, {{{ {ρ f}} {1 - {ρ f} ( {{ρ b}+{ρ f}} )}.{( {{{{ρ }}b}+{ρ f}} )}}} , depends only on the fluid, {ρ f}, and body, {{ρ }}b, density. Whereas these straightforward solutions work even at the liquid-gas interface in a significant number of cases, they do not work for generalized bodies undergoing buoyancy in combination with appreciable body density inhomogeneity, volume change (PIV), or volume rate-of-change (PIV and AFP). In these less common cases, the 3D body shape needs to be measured and resolved in time and space to estimate the unsteady body force. The analysis shows that accounting for the unsteady body force is straightforward to non

  6. Sex Differences in the Impact of Thinness, Overweight, Obesity, and Parental Height on Adolescent Height.

    Science.gov (United States)

    Pinhas-Hamiel, Orit; Reichman, Brian; Shina, Avi; Derazne, Estela; Tzur, Dorit; Yifrach, Dror; Wiser, Itay; Afek, Arnon; Shamis, Ari; Tirosh, Amir; Twig, Gilad

    2017-08-01

    The secular trend of increasing weight may lead to a decline in height gain compared with the genetic height potential. The impact of weight on height in healthy male and female adolescents compared with their genetic height was assessed. Height and weight were measured in Israeli adolescent military recrutees aged 16-19 years between 1967 and 2013. The study population comprised 355,229 recrutees for whom parental height measurements were documented. Subjects were classified into four body mass index percentile groups according to the U.S. Centers for Disease Control and Prevention body mass index percentiles for age and sex:obese). Short stature was defined as height ≤ third percentile and tall stature as height ≥ 90th percentile for age and sex. Overweight-obese females had a 73% increased risk for short stature (odds ratio [OR]: 1.73, 95% confidence interval [CI] = 1.51-1.97, p obese males had a 23% increased risk of being short (OR: 1.23, 95% CI = 1.10-1.37, p obese males and females had an increased risk of being short, and underweight females were significantly taller compared with their genetic height. The significantly increased height among underweight healthy females may reflect a potential loss of height gain in overweight-obese females. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  7. Measuring wintertime surface fluxes at the Tiksi observatory in northern Sakha (Yakutia)

    Science.gov (United States)

    Laurila, Thomas; Aurela, Mika; Hatakka, Juha; Tuovinen, Juha-Pekka; Asmi, Eija; Kondratyev, Vladimir; Ivakhov, Victor; Reshetnikov, Alexander; Makshtas, Alexander; Uttal, Taneil

    2013-04-01

    Tiksi hydrometeorological observatory has been equipped by new instrumentation for meteorology, turbulence, trace gas and aerosols studies as a joint effort by National Oceanic and Atmospheric Administration (NOAA), Roshydromet (Yakutian Hydrometeorological Service, Arctic and Antarctic Research Institute and Voeikov Main Geophysical Observatory units) and the Finnish Meteorological Institute (FMI). The site is close to the coast of the Laptev Sea on deep permafrost soil with low tundra vegetation and patches of arctic semidesert. Near-by terrain is gently sloping to the south. Further away they are hills in the NE- and W-directions. Turbulence (3-d wind components and sonic temperature) was measured at 10 Hz by USA-1Scientific sonic by Metek, Gmbh. Concentrations of CO2 and H2O were measured by LiCor LI7000 analyzer and CH4 concentrations by Los Gatos RMT200 analyzer. Measurement height was 2.5m. Active layer freeze up took place in extended October period. Methane and carbon dioxide emissions were observed up to early December. Emissions to the atmosphere were enhanced by turbulence created by high wind speeds. Midwinter conditions existed from the end of October to the beginning of April based on rather constant negative net radiation between 20-30 Wm-2 that cools the surface and forms highly stable stratification. Weather conditions are characterized by either low or high wind speed modes. Roughly half of the time wind speed was low, below 2 ms-1. Then, katabatic winds were common and air temperature was between -40..-30°C. High wind speeds, up to 24 ms-1, were observed during synoptic disturbances which lasted typically a few days. In this presentation we will show climatology of surface layer characteristics in late autumn and winter. We will show frequency of well-developed turbulence vs. katabatic low wind speed conditions and related atmospheric stability. The effect of wind speed on methane and carbon dioxide emissions during the freezing period will be

  8. Estimation of Total Tree Height from Renewable Resources Evaluation Data

    Science.gov (United States)

    Charles E. Thomas

    1981-01-01

    Many ecological, biological, and genetic studies use the measurement of total tree height. Until recently, the Southern Forest Experiment Station's inventory procedures through Renewable Resources Evaluation (RRE) have not included total height measurements. This note provides equations to estimate total height based on other RRE measurements.

  9. Response Surface Methods For Spatially-Resolved Optical Measurement Techniques

    Science.gov (United States)

    Danehy, P. M.; Dorrington, A. A.; Cutler, A. D.; DeLoach, R.

    2003-01-01

    Response surface methods (or methodology), RSM, have been applied to improve data quality for two vastly different spatially-resolved optical measurement techniques. In the first application, modern design of experiments (MDOE) methods, including RSM, are employed to map the temperature field in a direct-connect supersonic combustion test facility at NASA Langley Research Center. The laser-based measurement technique known as coherent anti-Stokes Raman spectroscopy (CARS) is used to measure temperature at various locations in the combustor. RSM is then used to develop temperature maps of the flow. Even though the temperature fluctuations at a single point in the flowfield have a standard deviation on the order of 300 K, RSM provides analytic fits to the data having 95% confidence interval half width uncertainties in the fit as low as +/- 30 K. Methods of optimizing future CARS experiments are explored. The second application of RSM is to quantify the shape of a 5-meter diameter, ultra-lightweight, inflatable space antenna at NASA Langley Research Center. Photogrammetry is used to simultaneously measure the shape of the antenna at approximately 500 discrete spatial locations. RSM allows an analytic model to be developed that describes the shape of the majority of the antenna with an uncertainty of 0.4 mm, with 95% confidence. This model would allow a quantitative comparison between the actual shape of the antenna and the original design shape. Accurately determining this shape also allows confident interpolation between the measured points. Such a model could, for example, be used for ray tracing of radio-frequency waves up to 95 GHz. to predict the performance of the antenna.

  10. Colour measurements of surfaces to evaluate the restoration materials

    Science.gov (United States)

    Lo Monaco, Angela; Marabelli, Maurizio; Pelosi, Claudia; Picchio, Rodolfo

    2011-06-01

    In this paper two case studies on the application of colour measurements for the evaluation of some restoration materials are discussed. The materials related to the research are: watercolours employed in restoration of wall paintings and preservative/consolidants for wood artifacts. Commercial watercolours, supplied by Maimeri, Windsor&Newton and Talens factories have been tested. Colour measurements have been performed by means of a reflectance spectrophotometer (RS) before and after accelerated ageing of watercolours at 92% relative humidity (RH) and in a Solar Box chamber. The experimental results show that watercolours based on natural earths and artificial ultramarine undergo the main colour changes, expressed as L*, a* and b* variations and total colour difference (▵E*). In the other cases colour differences depend on both watercolour typology and suppliers. The other example concerns the evaluation of colour change due to surface treatment of Poplar (Populus sp.) and chestnut (Castanea sativa L.) wood samples. The wooden samples have been treated with a novel organic preservative/consolidant product that has been tested also in a real case as comparison. The treated samples have been artificially aged in Solar Box chamber equipped with a 280 nm UV filter. Colour has been measured before and after the artificial ageing by means of a RS. Colour changes have been determined also for the main door of an historical mansion in Viterbo, made of chestnut wood, and exposed outdoors.

  11. Advanced metrology of surface defects measurement for aluminum die casting

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2011-07-01

    Full Text Available The scientific objective of the research is to develop a strategy to build computer based vision systems for inspection of surface defects inproducts, especially discontinuities which appear in castings after machining. In addition to the proposed vision inspection method theauthors demonstrates the development of the advanced computer techniques based on the methods of scanning to measure topography ofsurface defect in offline process control. This method allow to identify a mechanism responsible for the formation of casting defects. Also,the method allow investigating if the, developed vision inspection system for identification of surface defects have been correctlyimplemented for an online inspection. Finally, in order to make casting samples with gas and shrinkage porosity defects type, the LGT gas meter was used . For this task a special camera for a semi-quantitative assessment of the gas content in aluminum alloy melts, using a Straube-Pfeiffer method was used. The results demonstrate that applied solution is excellent tool in preparing for various aluminum alloysthe reference porosity samples, identified next by the computer inspection system.

  12. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    Science.gov (United States)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  13. Lucas Heights technology park

    International Nuclear Information System (INIS)

    1987-01-01

    The proposed Lucas Heights Technology Park will pound together the applied research programs of Government, tertiary and industry sectors, aiming to foster technology transfer particularly to the high-technology manufacturing industry. A description of the site is given along with an outline of the envisaged development, existing facilities and expertise. ills

  14. Practical application of the geometric geoid for heighting over ...

    African Journals Online (AJOL)

    This is because a geoid model is required to convert ellipsoidal heights to orthometric heights that are used in practice. A local geometric geoid ... The geoid height is expressed as a function of the local plane coordinates through a biquadratic surface polynomial, using 14 GPS/levelling points. Five points have been used ...

  15. Channel Storage change: a new remote sensed surface water measurement

    Science.gov (United States)

    Coss, S. P.; Durand, M. T.; Yi, Y.; Guo, Q.; Shum, C. K.; Allen, G. H.; Pavelsky, T.

    2017-12-01

    Here we present river channel storage change (CSC) measurements for 17 major world rivers from 2002-2016. We combined interpolated daily 1 km resolution Global River Radar Altimeter Time Series (GRRATS) river surface elevation data with static widths from the global river Global River Widths from Landsat (GRWL) dataset, to generate preliminary channel storage measurements. CSC is a previously unmeasured component of the terrestrial water balance It is a fundamental Earth science quantity with global bearing on floodplains, ecology, and geochemistry. CSC calculations require only remote sensed data, making them an ideal tool for studying remote regions where hydrological data is not easily accessible. CSC is uniquely suited to determine the role of hydrologic and hydraulic controls in basins with strong seasonal cycles (freeze-up and break-up). The cumulative CSC anomaly can impart spatial details that discharge measurements cannot. With this new measurement, we may be able to determine critical hydrological and hydraulic controls on rapidly changing systems like Arctic rivers. Results for Mississippi River indicate that peak CSC anomaly was the highest in 2011 (12.6 km3) and minimum CSC anomaly was in 2012 (-12.2 km3). Peak CSC has most frequently occurs in May (5 years), but has come as late in the year as July, and as early as January. Results for the Yukon River indicate that peak CSC anomaly was the highest in 2013 (13.9 km3) and minimum CSC anomaly was in 2010 (-14.2 km3). Peak CSC has most frequently come in early to mid-June (4-18), but has occurred in May (19-31) four years in the study period (three of the last 6 years) and once on April 30th.

  16. Measuring surface temperature of isolated neutron stars and related problems

    Science.gov (United States)

    Teter, Marcus Alton

    New and exciting results for measuring neutron star surface temperatures began with the successful launch of the Chandra X-ray observatory. Among these results are new detections of neutron star surface temperatures which have made it possible to seriously test neutron star thermal evolution theories. The important new temperature determination of the Vela pulsar (Pavlov, et al., 2001a) requires a non-standard cooling scenario to explain it. Apart from this result, we have measured PSR B1055-52's surface temperature in this thesis, determining that it can be explained by standard cooling with heating. Our spectral fit of the combined data from ROSAT and Chandra have shown that a three component model, two thermal blackbodies and an non-thermal power-law, is required to explain the data. Furthermore, our phase resolved spectroscopy has begun to shed light on the geometry of the hot spot on PSR B1055-52's surface as well as the structure of the magnetospheric radiation. Also, there is strong evidence for a thermal distribution over its surface. Most importantly, the fact that PSR B1055-52 does not have a hydrogen atmosphere has been firmly established. To reconcile these two key observations, on the Vela pulsar and PSR B1055-52, we tested neutron star cooling with neutrino processes including the Cooper pair neutrino emission process. Overall, it has been found that a phase change associated with pions being present in the cores of more massive neutron stars explains all current of the data. A transition from neutron matter to pion condensates in the central stellar core explains the difference between standard and non-standard cooling scenarios, because the superfluid suppression of pion cooling will reduce the emissivity of the pion direct URCA process substantially. A neutron star with a mass of [Special characters omitted.] with a medium stiffness equation of state and a T72 type neutron superfluid models the standard cooling case well. A neutron star of [Special

  17. Childhood height, adult height, and the risk of prostate cancer

    DEFF Research Database (Denmark)

    Bjerregaard, Lise Geisler; Aarestrup, Julie; Gamborg, Michael

    2016-01-01

    PURPOSE: We previously showed that childhood height is positively associated with prostate cancer risk. It is, however, unknown whether childhood height exerts its effects independently of or through adult height. We investigated whether and to what extent childhood height has a direct effect on ...

  18. Relationship between maternal pelvis height and other ...

    African Journals Online (AJOL)

    Relationship between maternal pelvis height and other anthropometric measurements in a multisite cohort of Ugandan mothers. Ian Guyton Munabi, Josaphat Byamugisha, Livingstone Luboobi, Samuel Abilemech Luboga, Florence Mirembe ...

  19. Double modulation pyrometry: A radiometric method to measure surface temperatures of directly irradiated samples

    Science.gov (United States)

    Potamias, Dimitrios; Alxneit, Ivo; Wokaun, Alexander

    2017-09-01

    The design, implementation, calibration, and assessment of double modulation pyrometry to measure surface temperatures of radiatively heated samples in our 1 kW imaging furnace is presented. The method requires that the intensity of the external radiation can be modulated. This was achieved by a rotating blade mounted parallel to the optical axis of the imaging furnace. Double modulation pyrometry independently measures the external radiation reflected by the sample as well as the sum of thermal and reflected radiation and extracts the thermal emission as the difference of these signals. Thus a two-step calibration is required: First, the relative gains of the measured signals are equalized and then a temperature calibration is performed. For the latter, we transfer the calibration from a calibrated solar blind pyrometer that operates at a different wavelength. We demonstrate that the worst case systematic error associated with this procedure is about 300 K but becomes negligible if a reasonable estimate of the sample's emissivity is used. An analysis of the influence of the uncertainties in the calibration coefficients reveals that one (out of the five) coefficient contributes almost 50% to the final temperature error. On a low emission sample like platinum, the lower detection limit is around 1700 K and the accuracy typically about 20 K. Note that these moderate specifications are specific for the use of double modulation pyrometry at the imaging furnace. It is mainly caused by the difficulty to achieve and maintain good overlap of the hot zone with a diameter of about 3 mm Full Width at Half Height and the measurement spot both of which are of similar size.

  20. Measuring surface current velocities in the Agulhas region with ASAR

    CSIR Research Space (South Africa)

    Rouault, MJ

    2010-01-01

    Full Text Available Surface current information collected over the Agulhas Current region and derived from the Doppler centroid anomalies of the Advanced Synthetic Aperture Radar (ASAR) are examined. The sources of errors and potential use of the radar surface...

  1. ROUGHNESS ON WOOD SURFACES AND ROUGHNESS MEASUREMENT METHODS

    OpenAIRE

    İsmail Aydın; Gürsel Çolakoğlu

    2003-01-01

    Some visual characteristics of wood such as color, pattern and texture determine the quality of manufactured products. Surface properties of wood material are important both in production and marketing after production. Initial studies related to the roughness of wood surface were begun in early 1950’s. However, no general agreed standardization can not have been developed for wood surfaces. Surface roughness of wood is function of the production process, product type and the natural anatomic...

  2. Measuring evaporation from soil surfaces for environmental and ...

    African Journals Online (AJOL)

    There are many reasons for the need to assess rates and quantities of evaporation or evapotranspiration from natural soil surfaces, the surfaces of deposits of mine or industrial waste, or soil-covered waste surfaces. These include assessing water balances for nearsurface soil strata, landfills, tailings dams and waste dumps ...

  3. APTCARE - Lucas Heights

    International Nuclear Information System (INIS)

    1986-05-01

    This plan details command co-ordination and support responses of Commonwealth and State Authorities in the event of an accident with offsite consequences at the Lucas Heights Research Laboratories. The plan has been prepared by the AAEC Local Liaison Working Party, comprising representatives of the Australian Atomic Energy Commission, NSW Police Department, NSW Board of Fire Commissioners, NSW State Emergency Services and Civil Defence Organisation, NSW Department of Health, NSW Department of Environment and Planning and Sutherland Shire Council

  4. Effects of drop size and measuring condition on static contact angle measurement on a superhydrophobic surface with goniometric technique

    International Nuclear Information System (INIS)

    Seo, Kwangseok; Kim, Minyoung; Kim, Do Hyun; Ahn, Jeong Keun

    2015-01-01

    It is not a simple task to measure a contact angle of a water drop on a superhydrophobic surface with sessile drop method, because a roll-off angle is very low. Usually contact angle of a water drop on a superhydrophobic surface is measured by fixing a drop with intentional defects on the surface or a needle. We examined the effects of drop size and measuring condition such as the use of a needle or defects on the static contact angle measurement on superhydrophobic surface. Results showed that the contact angles on a superhydrophobic surface remain almost constant within intrinsic measurement errors unless there is a wetting transition during the measurement. We expect that this study will provide a deeper understanding on the nature of the contact angle and convenient measurement of the contact angle on the superhydrophobic surface.

  5. Entrance surface dose measurements in pediatric radiological examinations

    International Nuclear Information System (INIS)

    Ribeiro, L.A.; Yoshimura, E.M.

    2008-01-01

    A survey of pediatric radiological examinations was carried out in a reference pediatric hospital of the city of Sao Paulo, in order to investigate the doses to children undergoing conventional X-ray examinations. The results showed that the majority of pediatric patients are below 4 years, and that about 80% of the examinations correspond to chest projections. Doses to typical radiological examinations were measured in vivo with thermoluminescent dosimeters (LiF: Mg, Ti and LiF: Mg, Cu, P) attached to the skin of the children to determine entrance surface dose (ESD). Also homogeneous phantoms were used to obtain ESD to younger children, because the technique uses a so small kVp that the dosimeters would produce an artifact image in the patient radiograph. Four kinds of pediatric examinations were investigated: three conventional examinations (chest, skull and abdomen) and a fluoroscopic procedure (barium swallow). Relevant information about kVp and mAs values used in the examinations was collected, and we discuss how these parameters can affect the ESD. The ESD values measured in this work are compared to reference levels published by the European Commission for pediatric patients. The results obtained (third-quartile of the ESD distribution) for chest AP examinations in three age groups were: 0.056 mGy (2-4 years old); 0.068 mGy (5-9 years old); 0.069 mGy (10-15 years old). All of them are below the European reference level (0.100 mGy). ESD values measured to the older age group in skull and abdomen AP radiographs (mean values 3.44 and 1.20 mGy, respectively) are above the European reference levels (1.5 mGy to skull and 1.0 mGy to abdomen). ESD values measured in the barium swallow examination reached 10 mGy in skin regions corresponding to thyroid and esophagus. It was noticed during this survey that some technicians use, improperly, X-ray fluoroscopy in conventional examinations to help them in positioning the patient. The results presented here are a

  6. Does BMI generated by self-reported height and weight measure up in older adults from middle-income countries? Results from the study on global AGEing and adult health (SAGE).

    Science.gov (United States)

    Gildner, Theresa E; Barrett, Tyler M; Liebert, Melissa A; Kowal, Paul; Snodgrass, J Josh

    2015-01-01

    Self-reported (SR) body mass index (BMI) values are often used to determine obesity prevalence. However, individuals frequently overestimate their height and underestimate their weight, resulting in artificially lower obesity prevalence rates. These patterns are especially apparent among older adults and overweight individuals. The present cross-sectional study uses nationally representative datasets from five countries to assess the accuracy of SR BMI values in diverse settings. Samples of older adults (≥50 years old) and comparative samples of younger adults (18-49 years old) were drawn from five middle-income countries (China, India, Mexico, Russian Federation, and South Africa) in the World Health Organization's Study on global AGEing and adult health (SAGE). Participant-reported and researcher-obtained height and weight measures were used to calculate SR and measured BMI, respectively. Paired t-tests assessed differences between SR and measured BMI values by country. Linear regressions examined the contribution of measured weight and age to differences between SR and measured BMI. Significant differences between SR and measured BMI values were observed (p BMI in all countries (p BMI discrepancy, except in China (p BMI may not accurately reflect measured BMI in middle-income countries, but the direction of this discrepancy varies by country. This has considerable implications for obesity-related disease estimates reliant on SR data.

  7. Adaptive Layer Height During DLP Materials Processing

    DEFF Research Database (Denmark)

    Pedersen, David Bue; Zhang, Yang; Nielsen, Jakob Skov

    2016-01-01

    This research aim to show how manufacturing speeds during vat polymerisation can be vastly increased through an adaptive layer height strategy that takes the geometry into account through analysis of the relationship between layer height, cross-section variability and surface structure. This allows...... for considerable process speedup during the Additive Manufacture of components that contain areas of low cross-section variability, at no loss of surface quality. The adaptive slicing strategy was tested with a purpose built vat polymerisation system and numerical engine designed and constructed to serve as a Next...

  8. Littoral Measurements Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Barny units measure ocean currents and sea surface heights on continental shelves and in ocean straits. SEPTR units are similar to Barnys but also record...

  9. On the measurement of the surface energy budget over a land ...

    Indian Academy of Sciences (India)

    The measurement of surface energy balance over a land surface in an open area in Bangalore is reported. Measurements of all variables needed to calculate the surface energy balance on time scales longer than a week are made. Components of radiative fluxes are measured while sensible and latent heat fluxes are ...

  10. Final height in elite male artistic gymnasts.

    Science.gov (United States)

    Georgopoulos, Neoklis A; Theodoropoulou, Anastasia; Roupas, Nikolaos D; Armeni, Anastasia K; Koukkou, Eftychia; Leglise, Michel; Markou, Kostas B

    2012-01-01

    Elite male artistic gymnasts (AG) are exposed to high levels of physical and psychological stress during adolescence and experience a significant late maturation in both linear growth and pubertal development. The aim of the present study was to determine the impact of intensive physical training on the adult final height in elite male AG. This study is unique in character, as all variables were measured on the field of competition. The study was prospective and longitudinal; however, the current analysis of data is cross-sectional. Data from 86 elite male AG were obtained during the gymnastics competitions of European and World Championships. Clinical evaluation included height and weight measurements, as well as assessment of pubic hair and genital development according to Tanner's stages of pubertal development. The laboratory investigation included determination of skeletal maturation. All athletes completed a questionnaire that included questions on personal (onset and intensity of training, number of competitions per year) and family data (paternal and maternal heights). Male AG were below the 50th percentile for both final height and weight. Elite male AG had final height standard deviation score (SDS) lower than their genetic predisposition. Final height SDS was correlated positively with target height SDS (r = 0.430, p research project, the International Federation of Gymnastics has increased the age limit for participants in international gymnastics competitions by 1 year.

  11. Social inequalities in height: persisting differences today depend upon height of the parents.

    Directory of Open Access Journals (Sweden)

    Bruna Galobardes

    Full Text Available Substantial increases in height have occurred concurrently with economic development in most populations during the last century. In high-income countries, environmental exposures that can limit genetic growth potential appear to have lessened, and variation in height by socioeconomic position may have diminished. The objective of this study is to investigate inequalities in height in a cohort of children born in the early 1990s in England, and to evaluate which factors might explain any identified inequalities.12,830 children from The Avon Longitudinal Study of Parents and Children (ALSPAC, a population based cohort from birth to about 11.5 years of age, were used in this analysis. Gender- and age-specific z-scores of height at different ages were used as outcome variables. Multilevel models were used to take into account the repeated measures of height and to analyze gender- and age-specific relative changes in height from birth to 11.5 years. Maternal education was the main exposure variable used to examine socioeconomic inequalities. The roles of parental and family characteristics in explaining any observed differences between maternal education and child height were investigated. Children whose mothers had the highest education compared to those with none or a basic level of education, were 0.39 cm longer at birth (95% CI: 0.30 to 0.48. These differences persisted and at 11.5 years the height difference was 1.4 cm (95% CI: 1.07 to 1.74. Several other factors were related to offspring height, but few changed the relationship with maternal education. The one exception was mid-parental height, which fully accounted for the maternal educational differences in offspring height.In a cohort of children born in the 1990s, mothers with higher education gave birth to taller boys and girls. Although height differences were small they persisted throughout childhood. Maternal and paternal height fully explained these differences.

  12. Optimization of Truss Height

    Directory of Open Access Journals (Sweden)

    Tomas Ulitinas

    2011-04-01

    Full Text Available The article analyzes the task in truss height and in the optimization of the cross-sections of their elements. Element cross-sections are designed of steel profiles considering requirements for strength, stability and rigidity. A mathematical model is formulated as a nonlinear mathematical programming problem. It is solved as an iterative process, using mathematical software package “MATLAB” routine “fmincon”. The ratio of buckling is corrected in the each iteration. Optimization results are compared with those obtained applying software package “Robot Millennium”.Article in Lithuanian

  13. RELATIONSHIP BETWEEN HEIGHT, SITTING HEIGHT AND SUBISCHIAL LEG LENGTH IN DUTCH CHILDREN - PRESENTATION OF NORMAL VALUES

    NARCIS (Netherlands)

    GERVER, WJM; DEBRUIN, R

    A widely used method of judging body proportions is to consider the ratio of sitting height to height (SH/H) related to age. A drawback of this method is that only one derived variable is used. A pairwise consideration of the original measurements provides more information. In this study data from

  14. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    surfaces in use have changed - for instance to road surface types with less noise from wheel passages. Because of this, a co-operation between the road administrations of the Nordic countries (abbreviated NMF) decided to construct a portable instrument to be used on selections of traffic roads within...

  15. Measurement of Sky Surface Brightness Fluctuations at λ=4 Microns

    Science.gov (United States)

    Xu, Jing; Bock, James J.; Ganga, Ken M.; Gorjian, Varoujan; Uemizu, Kazunori; Kawada, Mitsunobu; Lange, Andrew E.; Matsumoto, Toshio; Watabe, Toyoki

    2002-12-01

    We present a measurement of faint-source confusion in deep, wide-field 4 μm images. The 1.8d×1.8d images with 17" resolution are centered about the nearby edge-on spiral galaxies NGC 4565 and NGC 5907. After removing statistical noise and gain fluctuations in the focal plane array, we measure spatial fluctuations in the sky brightness to be δνIν=2.74+/-0.14 nW m-2 sr-1, approximately 1% of the diffuse background level observed in a single pixel. The brightness fluctuations are confirmed to be associated with the sky by subtracting sequential images of the same region. An autocorrelation analysis shows the fluctuations are well described by unresolved point sources. We see no evidence for surface brightness fluctuations on larger angular scales (2'S)=1.04+0.86-0.34 nW m-2 sr-1 to the cosmic infrared background, evaluated at S=4.0×10-8 nW m-2. From the fluctuation data we can determine the integrated source counts N(>S)=1.79+0.26-0.40×107 sr-1, evaluated at S=4.0×10-8 nW m-2. The observed fluctuations are consistent with reddened K-band galaxy number counts. The number counts of extracted point sources with flux νFν>6.3×10-7 nW m-2 are dominated by stars and agree well with the Galactic stellar model of Wright & Reese. Removing the stellar contribution from DIRBE maps with zodiacal subtraction results in a residual brightness of 14.0+/-2.6 (22.2+/-5.9) nW m-2 sr-1 at 3.5 (4.9) μm for the NGC 5907 field and 24.0+/-2.7 (36.8+/-6.0) nW m-2 sr-1 at 3.5 (4.9) μm for the NGC 4565 field. The NGC 5907 residuals are consistent with tentative detections of the infrared background reported by Dwek & Arendt, Wright & Reese, and Gorjian, Wright, & Chary.

  16. Comparison of plantar pressure between flat and normal feet when crossing an obstacle at different heights.

    Science.gov (United States)

    Han, Jin-Tae; Lee, Jung-Hoon; Lee, Eun-Ju; Lim, Chang-Hun; Kim, Won-Bok

    2015-01-01

    The purpose of this study is to compare the plantar foot pressure and the center of pressure (COP) pathway of normal and flat feet while crossing an obstacle at different heights. Nineteen subjects (10 normal feet, 9 flat feet) participated in this study. The plantar foot surface was divided into the following seven regions for pressure measurement: two toe regions, three forefoot regions, one midfoot region, and one heel region. A one-way ANOVA with repeated measurements was used to compare the plantar foot pressure of normal and flat feet according to the obstacle height. The trend analysis showed a quadratic trend during level walking for the normal foot group, but a linear trend appeared as the obstacle height increased. In the flat foot group, the trend analysis showed a linear trend regardless of the obstacle height. In the 2nd-3rd metatarsal head region, the plantar pressure of the flat foot group increased more than the normal foot group as the obstacle height increased; however, in the 4th-5th metatarsal head region, the plantar pressure in flat feet was lower than in normal feet. In the heel region, the plantar pressure in both groups generally increased as the obstacle height increased, but the plantar pressure in the flat foot group was lower than in the normal foot group. We believe that, due to a loss of longitudinal arch, the COP path and plantar pressure of flat feet may be different from normal feet when crossing obstacles of different heights.

  17. Memory for target height is scaled to observer height.

    Science.gov (United States)

    Twedt, Elyssa; Crawford, L Elizabeth; Proffitt, Dennis R

    2012-04-01

    According to the embodied approach to visual perception, individuals scale the environment to their bodies. This approach highlights the central role of the body for immediate, situated action. The present experiments addressed whether body scaling--specifically, eye-height scaling--occurs in memory when action is not immediate. Participants viewed standard targets that were either the same height as, taller than, or shorter than themselves. Participants then viewed a comparison target and judged whether the comparison was taller or shorter than the standard target. Participants were most accurate when the standard target height matched their own heights, taking into account postural changes. Participants were biased to underestimate standard target height, in general, and to push standard target height away from their own heights. These results are consistent with the literature on eye-height scaling in visual perception and suggest that body scaling is not only a useful metric for perception and action, but is also preserved in memory.

  18. High-Resolution Forest Canopy Height Estimation in an African Blue Carbon Ecosystem

    Science.gov (United States)

    Lagomasino, David; Fatoyinbo, Temilola; Lee, Seung-Kuk; Simard, Marc

    2015-01-01

    Mangrove forests are one of the most productive and carbon dense ecosystems that are only found at tidally inundated coastal areas. Forest canopy height is an important measure for modeling carbon and biomass dynamics, as well as land cover change. By taking advantage of the flat terrain and dense canopy cover, the present study derived digital surface models (DSMs) using stereophotogrammetric techniques on high-resolution spaceborne imagery (HRSI) for southern Mozambique. A mean-weighted ground surface elevation factor was subtracted from the HRSI DSM to accurately estimate the canopy height in mangrove forests in southern Mozambique. The mean and H100 tree height measured in both the field and with the digital canopy model provided the most accurate results with a vertical error of 1.18-1.84 m, respectively. Distinct patterns were identified in the HRSI canopy height map that could not be discerned from coarse shuttle radar topography mission canopy maps even though the mode and distribution of canopy heights were similar over the same area. Through further investigation, HRSI DSMs have the potential of providing a new type of three-dimensional dataset that could serve as calibration/validation data for other DSMs generated from spaceborne datasets with much larger global coverage. HSRI DSMs could be used in lieu of Lidar acquisitions for canopy height and forest biomass estimation, and be combined with passive optical data to improve land cover classifications.

  19. An investigation of cloud base height in Chiang Mai

    Science.gov (United States)

    Peengam, S.; Tohsing, K.

    2017-09-01

    Clouds play very important role in the variation of surface solar radiation and rain formation. To understand this role, it is necessary to know the physical and geometrical of properties of cloud. However, clouds vary with location and time, which lead to a difficulty to obtain their properties. In this work, a ceilometer was installed at a station of the Royal Rainmaking and Agricultural Aviation Department in Chiang Mai (17.80° N, 98.43° E) in order to measure cloud base height. The cloud base height data from this instrument were compared with those obtained from LiDAR, a more sophisticated instrument installed at the same site. It was found that the cloud base height from both instruments was in reasonable agreement, with root mean square difference (RMSD) and mean bias difference (MBD) of 19.21% and 1.58%, respectively. Afterward, a six-month period (August, 2016-January, 2017) of data from the ceilometer was analyzed. The results show that mean cloud base height during this period is 1.5 km, meaning that most clouds are in the category of low-level cloud.

  20. Analysis of the thermal structure of the "Ora del Garda" wind from airborne and surface measurements

    Science.gov (United States)

    Laiti, L.; Zardi, D.; de Franceschi, M.

    2010-09-01

    Systems of daily-periodic valley winds typically develop in the Alps, driven by the interaction between the thermally forced motion of air masses and the complex orographic configuration. The occurrence of large lakes can mark these phenomena with local peculiarities. This study investigates a well known valley/lake breeze phenomenon, the so-called Ora del Garda. The latter is a diurnal wind originating in the late morning of sunny days on the northern shores of Lake Garda, channelling into the Sarca River Valley and the Lakes Valley nearby, and reaching, on days of greater intensity, the Adige River Valley, where it gets mixed with the local up-valley winds and produces a strong and gusty local flow. The Ora blows very regularly on sunny days under fair weather conditions, from late spring to early autumn, and marks local weather conditions in the area. In order to explore how the development of this wind affects the boundary layer processes in the valleys, and in particular temperature and humidity structures, three measurements campaigns were performed in 1998-1999, including flights of an instrumented light airplane. Each flight trajectory explored three or four sections along the valley at specific locations (namely over the lake coast, at half valley, at the end of the valley). By following spiralling paths on vertical planes oriented either along or cross valley, data allowing detailed pictures of atmospheric structure on these sections were collected. At the same time data from surface weather stations located both on the valley floor and on the sidewall slopes were collected and analysed. In particular measurements from radiometers allowed to monitor the evolution of the radiation forcing the valley wind. For each single section suitable analytical expressions for mean vertical temperature and humidity profiles were first inferred to determine the dominating vertical structure. Then the characteristic spatial scales of variability of local deviations from

  1. Measurement of magnetic surfaces on the Compact Auburn Torsatron

    International Nuclear Information System (INIS)

    Henderson, M.A.; Gandy, R.F.; Hanson, J.D.; Knowlton, S.F.; Swanson, D.G.

    1992-01-01

    The magnetic flux surfaces of the Compact Auburn Torsatron have been experimentally mapped in a variety of magnetic configurations. The magnetic surface mapping was done using the phosphor screen technique. The results are compared with an extensive computer model in order to validate the design coil structure and determine what modifications are needed to correct any minor winding errors. In initial field mapping experiments, a large up--down asymmetry was identified in the vacuum magnetic surfaces. A set of mapping studies was used to characterize the error through addition of terms to the coil winding law. The error was corrected with the use of a radial trim coil

  2. Arctic Ocean gravity, geoid and sea-ice freeboard heights from ICESat and GRACE

    DEFF Research Database (Denmark)

    Forsberg, René; Skourup, Henriette

    2005-01-01

    ICESat laser measurements provide a high-resolution mapping of the sea-ice surface of the Arctic Ocean, which can be inverted to determine gravity anomalies and sea-ice freeboard heights by a "lowest-level'' filtering scheme. In this paper we use updated terrestrial gravity data from the Arctic...... Gravity Project in combination with GRACE gravity field models to derive an improved Arctic geoid model. This model is then used to convert ICESat measurements to sea-ice freeboard heights with a coarse lowest-level surface method. The derived freeboard heights show a good qualitative agreement...... to the coverage of multi-year sea-ice; however, comparison to an airborne lidar underflight north of Greenland shows that the lowest-level filtering scheme may introduce a bias. We finally use the ICESat and GRACE results to derive new gravity anomalies by Fourier inversion. The satellite-only gravity field shows...

  3. SMEX03 Surface and Soil Temperature Measurements: Alabama

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains land surface temperature and soil temperature data at depths of 1 cm, 5 cm, and 10 cm collected during the Soil Moisture Experiment 2003...

  4. Can in vivo surface dental enamelmicrobiopsies be used to measure remote lead exposure?

    Science.gov (United States)

    Olympio, Kelly Polido Kaneshiro; Huila, Manuel Fernando Gonzalez; de Almeida Baldini Cardoso, Cristiane; da Silva Ferreira, Ana Paula Sacone; Ortiz, Adrielly Garcia; Toma, Henrique Eisi; da Silva, Ricardo Henrique Alves; Luz, Maciel Santos; Cardoso, Maria Regina Alves; Kelmer, Gislayne Aparecida Rodrigues; de Oliveira, Pedro Vitoriano; Bechara, Etelvino José Henriques; Günhter, Wanda Maria Risso; Buzalaf, Marília Afonso Rabelo

    2017-12-20

    Measuring lead in the surface dental enamel (SDE) using biopsies is a rapid, safe, and painless procedure. The dental enamel lead levels (DELLs) decrease from the outermost superficial layer to the inner layer of dental enamel, which becomes crucial for the biopsy depth (BD) measurement. However, whether the origin of lead found in SDE is fully endogenous is not yet established. There is also controversy about the biopsy protocol. The aims of this study were to investigate if DELLs are altered by extrinsic contamination (A) and to evaluate the real geometric figure formed by the erosion provoked by biopsy procedure and the respective BD in SDE (B). To accomplish the aim A, lead from 90 bovine incisor crowns lead was determined by graphite furnace atomic absorption spectrometer as a function of exposure time and lead concentration. Two biopsies were performed in each tooth, before and after lead exposure. Six 15-tooth groups differed by exposure time (1 or 30 min) and lead concentrations (A. 0 mg/L-placebo, B. 0.01 mg/L-standard for drinking water, or C. 0.06 mg/L-concentration found in contaminated groundwater). Phosphorus was determined by an inductively coupled plasm optical emission spectrometer to quantify the enamel removed. To compare intakes/losses of lead in SDE among the groups, values of DELL differences between before and after lead exposure were compared by ANOVA (p bottom surface area, analyzed by microscopy, showed an irregular area, with regions of peaks and valleys, where areas with depth ranging from 0.2 (peaks) to 1.8 μm (valleys) (± 0.1 μm) could be found. BD carried out in vivo is commonly calculated using the cylinder height formula. The real BD was shown to be very similar to already published data. In conclusion, the SDE of erupted teeth does not seem to be susceptible to environmental lead intake, being thus reliable to measure remote exposures to lead.

  5. Measuring the surface-heating of medical ultrasonic probes

    International Nuclear Information System (INIS)

    Kollmann, Chr; Vacariu, G; Fialka-Moser, V; Bergmann, H

    2004-01-01

    Due to converting losses the probe's surface itself is heated up, especially when emitting into air. Possible temperature increases in an ensemble of 15 different diagnostic and therapeutic ultrasound probes from 7 manufacturers in the frequency range between 0.05-7.5 MHz have been examined. Surface temperatures were detected by means of a calibrated IR-thermographic camera using a scheme of various power and pulse settings, as well as different imaging modalitites as used in clinical routine. Depending on the setup and the output power, the absolute surface temperatures of some of the probes emitting in air can be beyond 43 deg. C within 5-7 min.; a maximum surface temperature of 84 deg. C has been detected. Continuous mode or high pulse repetition frequencies on the therapeutic system side, small focused Doppler modes on the diagnostic system side combined with increased emitted acoustic intensities result in high surface temperatures. Within a worst case scenario a potential risk of negative skin changes (heat damage) or non-optimal therapeutic effects seems to be possible if a therapeutic system is used very often and if its emission continues unintentionally. In general the user should be aware that low emission intensities of e.g. 50 mW cm -2 could already produce hot surfaces

  6. Challenges in Defining Tsunami Wave Height

    Science.gov (United States)

    Stroker, K. J.; Dunbar, P. K.; Mungov, G.; Sweeney, A.; Arcos, N. P.

    2017-12-01

    The NOAA National Centers for Environmental Information (NCEI) and co-located World Data Service for Geophysics maintain the global tsunami archive consisting of the historical tsunami database, imagery, and raw and processed water level data. The historical tsunami database incorporates, where available, maximum wave heights for each coastal tide gauge and deep-ocean buoy that recorded a tsunami signal. These data are important because they are used for tsunami hazard assessment, model calibration, validation, and forecast and warning. There have been ongoing discussions in the tsunami community about the correct way to measure and report these wave heights. It is important to understand how these measurements might vary depending on how the data were processed and the definition of maximum wave height. On September 16, 2015, an 8.3 Mw earthquake located 48 km west of Illapel, Chile generated a tsunami that was observed all over the Pacific region. We processed the time-series water level data for 57 tide gauges that recorded this tsunami and compared the maximum wave heights determined from different definitions. We also compared the maximum wave heights from the NCEI-processed data with the heights reported by the NOAA Tsunami Warning Centers. We found that in the near field different methods of determining the maximum tsunami wave heights could result in large differences due to possible instrumental clipping. We also found that the maximum peak is usually larger than the maximum amplitude (½ peak-to-trough), but the differences for the majority of the stations were Warning Centers. Since there is currently only one field in the NCEI historical tsunami database to store the maximum tsunami wave height, NCEI will consider adding an additional field for the maximum peak measurement.

  7. Boys with a simple delayed puberty reach their target height.

    Science.gov (United States)

    Cools, B L M; Rooman, R; Op De Beeck, L; Du Caju, M V L

    2008-01-01

    Final height in boys with delayed puberty is thought to be below target height. This conclusion, however, is based on studies that included patients with genetic short stature. We therefore studied final height in a group of 33 untreated boys with delayed puberty with a target height >-1.5 SDS. Standing height, sitting height, weight and arm span width were measured in each patient. Final height was predicted by the method of Greulich and Pyle using the tables of Bailey and Pinneau for retarded boys at their bone age (PAH1) and the tables of Bailey and Pinneau for average boys plus six months (PAH2). Mean final height (175.8 +/- 6.5 cm) was appropriate for the mean target height (174.7 +/- 4.5 cm). The prediction method of Bailey and Pinneau overestimated the final height by 1.4 cm and the modified prediction method slightly underestimated the final height (-0.15 cm). Boys with untreated delayed puberty reach a final height appropriate for their target height. Final height was best predicted by the method of Bailey and Pinneau using the tables for average boys at their bone age plus six months. Copyright 2008 S. Karger AG, Basel.

  8. Removal of Surface-Reflected Light for the Measurement of Remote-Sensing Reflectance from an Above-Surface Platform

    Science.gov (United States)

    2010-12-06

    REPORT DATE IDD-MM- YYYY) 14-02-2011 2. REPORT TYPE Journal Article 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Removal of Surface...impossible to obtain Rr, from measurements of vertical profiles of Lu and Elt [6]. During the experiment, the surface was calm [see Fig. 8(a)] and

  9. Wind height distribution influence on offshore wind farm feasibility study

    Science.gov (United States)

    Benassai, Guido; Della Morte, Renata; Matarazzo, Antonio; Cozzolino, Luca

    2015-04-01

    The economic feasibility of offshore wind power utilization depends on the favourable wind conditions offshore as compared to sites on land. The higher wind speeds have to compensate the additional cost of offshore developments. However, not only the mean wind speed is different, but the whole flow regime, as can be seen in the vertical wind speed profile. The commonly used models to describe this profile have been developed mainly for land sites, so they have to be verified on the basis of field data. Monin-Obukhov theory is often used for the description of the wind speed profile at a different height with respect to a measurement height. Starting from the former, , the profile is predicted using two parameters, Obukhov length and sea surface roughness. For situations with near-neutral and stable atmospheric stratification and long (>30km) fetch, the wind speed increase with height is larger than what is predicted from Monin-Obukhov theory. It is also found that this deviation occurs at wind speeds important for wind power utilization, mainly at 5-9 ms-1. In the present study the influence of these aspects on the potential site productivity of an offshore wind farm were investigated, namely the deviation from the theory of Monin-Obukhov due to atmospheric stability and the influence of the fetch length on the Charnock model. Both these physical effects were discussed and examined in view of a feasibility study of a site for offshore wind farm in Southern Italy. Available data consisted of time histories of wind speeds and directions collected by National Tidegauge Network (Rete Mareografica Nazionale) at the height of 10m a.s.l. in ports. The theory of Monin-Obukhov was used to extrapolate the data to the height of the wind blades, while the Charnock model was used to extend the wind speed on the sea surface from the friction velocity on the ground. The models described were used to perform calculations for a feasibility study of an offshore wind farm in Southern

  10. An AFM-based pit-measuring method for indirect measurements of cell-surface membrane vesicles

    International Nuclear Information System (INIS)

    Zhang, Xiaojun; Chen, Yuan; Chen, Yong

    2014-01-01

    Highlights: • Air drying induced the transformation of cell-surface membrane vesicles into pits. • An AFM-based pit-measuring method was developed to measure cell-surface vesicles. • Our method detected at least two populations of cell-surface membrane vesicles. - Abstract: Circulating membrane vesicles, which are shed from many cell types, have multiple functions and have been correlated with many diseases. Although circulating membrane vesicles have been extensively characterized, the status of cell-surface membrane vesicles prior to their release is less understood due to the lack of effective measurement methods. Recently, as a powerful, micro- or nano-scale imaging tool, atomic force microscopy (AFM) has been applied in measuring circulating membrane vesicles. However, it seems very difficult for AFM to directly image/identify and measure cell-bound membrane vesicles due to the similarity of surface morphology between membrane vesicles and cell surfaces. Therefore, until now no AFM studies on cell-surface membrane vesicles have been reported. In this study, we found that air drying can induce the transformation of most cell-surface membrane vesicles into pits that are more readily detectable by AFM. Based on this, we developed an AFM-based pit-measuring method and, for the first time, used AFM to indirectly measure cell-surface membrane vesicles on cultured endothelial cells. Using this approach, we observed and quantitatively measured at least two populations of cell-surface membrane vesicles, a nanoscale population (<500 nm in diameter peaking at ∼250 nm) and a microscale population (from 500 nm to ∼2 μm peaking at ∼0.8 μm), whereas confocal microscopy only detected the microscale population. The AFM-based pit-measuring method is potentially useful for studying cell-surface membrane vesicles and for investigating the mechanisms of membrane vesicle formation/release

  11. Measuring the role of seagrasses in regulating sediment surface elevation.

    Science.gov (United States)

    Potouroglou, Maria; Bull, James C; Krauss, Ken W; Kennedy, Hilary A; Fusi, Marco; Daffonchio, Daniele; Mangora, Mwita M; Githaiga, Michael N; Diele, Karen; Huxham, Mark

    2017-09-20

    Seagrass meadows provide numerous ecosystem services and their rapid global loss may reduce human welfare as well as ecological integrity. In common with the other 'blue carbon' habitats (mangroves and tidal marshes) seagrasses are thought to provide coastal defence and encourage sediment stabilisation and surface elevation. A sophisticated understanding of sediment elevation dynamics in mangroves and tidal marshes has been gained by monitoring a wide range of different sites, located in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya, Tanzania and Saudi Arabia, in both seagrass and unvegetated control plots in the low intertidal and shallow subtidal zone. The presence of seagrass had a highly significant, positive impact on surface elevation at all sites. Combined data from the current work and the literature show an average difference of 31 mm per year in elevation rates between vegetated and unvegetated areas, which emphasizes the important contribution of seagrass in facilitating sediment surface elevation and reducing erosion. This paper presents the first multi-site study for sediment surface elevation in seagrasses in different settings and species.

  12. Measuring the role of seagrasses in regulating sediment surface elevation

    KAUST Repository

    Potouroglou, Maria

    2017-09-13

    Seagrass meadows provide numerous ecosystem services and their rapid global loss may reduce human welfare as well as ecological integrity. In common with the other \\'blue carbon\\' habitats (mangroves and tidal marshes) seagrasses are thought to provide coastal defence and encourage sediment stabilisation and surface elevation. A sophisticated understanding of sediment elevation dynamics in mangroves and tidal marshes has been gained by monitoring a wide range of different sites, located in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya, Tanzania and Saudi Arabia, in both seagrass and unvegetated control plots in the low intertidal and shallow subtidal zone. The presence of seagrass had a highly significant, positive impact on surface elevation at all sites. Combined data from the current work and the literature show an average difference of 31 mm per year in elevation rates between vegetated and unvegetated areas, which emphasizes the important contribution of seagrass in facilitating sediment surface elevation and reducing erosion. This paper presents the first multi-site study for sediment surface elevation in seagrasses in different settings and species.

  13. A Mobile System for Measuring Water Surface Velocities Using Unmanned Aerial Vehicle and Large-Scale Particle Image Velocimetry

    Science.gov (United States)

    Chen, Y. L.

    2015-12-01

    Measurement technologies for velocity of river flow are divided into intrusive and nonintrusive methods. Intrusive method requires infield operations. The measuring process of intrusive methods are time consuming, and likely to cause damages of operator and instrument. Nonintrusive methods require fewer operators and can reduce instrument damages from directly attaching to the flow. Nonintrusive measurements may use radar or image velocimetry to measure the velocities at the surface of water flow. The image velocimetry, such as large scale particle image velocimetry (LSPIV) accesses not only the point velocity but the flow velocities in an area simultaneously. Flow properties of an area hold the promise of providing spatially information of flow fields. This study attempts to construct a mobile system UAV-LSPIV by using an unmanned aerial vehicle (UAV) with LSPIV to measure flows in fields. The mobile system consists of a six-rotor UAV helicopter, a Sony nex5T camera, a gimbal, an image transfer device, a ground station and a remote control device. The activate gimbal helps maintain the camera lens orthogonal to the water surface and reduce the extent of images being distorted. The image transfer device can monitor the captured image instantly. The operator controls the UAV by remote control device through ground station and can achieve the flying data such as flying height and GPS coordinate of UAV. The mobile system was then applied to field experiments. The deviation of velocities measured by UAV-LSPIV of field experiments and handhold Acoustic Doppler Velocimeter (ADV) is under 8%. The results of the field experiments suggests that the application of UAV-LSPIV can be effectively applied to surface flow studies.

  14. Optical Roughness Measuring Instrument For Fine-Machined Surfaces

    Science.gov (United States)

    Brodmann, Rainer; Gerstorfer, Oskar; Thurn, Gerd

    1985-06-01

    The roughness measuring instrument described is based on light scattering and is suitable in a wide range of applications, especially in micro-machining. The most important properties are the sensitivity in the measuring range from below 0.005 i.im up to 2µm (Ra value), the independence of the reflection coefficient due to normalization, and the larger tolerance of measur-ing distance of +/-2 mm.

  15. Calculation of the surface potential and surface charge density by measurement of the three-phase contact angle.

    Science.gov (United States)

    Horiuchi, H; Nikolov, A; Wasan, D T

    2012-11-01

    The silica/silicon wafer is widely used in the semiconductor industry in the manufacture of electronic devices, so it is essential to understand its physical chemistry and determine the surface potential at the silica wafer/water interface. However, it is difficult to measure the surface potential of a silica/silicon wafer directly due to its high electric resistance. In the present study, the three-phase contact angle (TPCA) on silica is measured as a function of the pH. The surface potential and surface charge density at the silica/water surface are calculated by a model based on the Young-Lippmann equation in conjunction with the Gouy-Chapman model for the electric double layer. In measurements of the TPCA on silica, two distinct regions were identified with a boundary at pH 9.5-showing a dominance of the surface ionization of silanol groups below pH 9.5 and a dominance of the dissolution of silica into the aqueous solution above pH 9.5. Since the surface chemistry changes above pH 9.5, the model is applied to solutions below pH 9.5 (ionization dominant) for the calculation of the surface potential and surface charge density at the silica/aqueous interface. In order to evaluate the model, a galvanic mica cell was made of a mica sheet and the surface potential was measured directly at the mica/water interface. The model results are also validated by experimental data from the literature, as well as the results obtained by the potentiometric titration method and the electro-kinetic measurements. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Components of adult height and height loss. Secular trend and effects of aging in women in the DOM project

    NARCIS (Netherlands)

    van Leer, E M; van Noord, P.A.H.; Seidell, J C

    Between 1984 and 1987, adult height, sitting height, arm span, and iliac crest height were measured in 13,386 women of the DOM project. Combined effects of secular trends between cohorts born in 1911 to 1945 and aging between ages 40 to 74 years showed a decrease in stature of 4.9 +/- 0.3 cm (mean

  17. Measuring of noise and wearing of quiet surfaces

    OpenAIRE

    Raitanen, Nina

    2005-01-01

    When using surfaces with special qualities, there is a need for tools to assess these qualities. Two methods, SPB (Statistical Pass-by) and CPX (Close Proximity), have been used for testing the noise properties of the surfaces in the other countries. Both of these methods had to be modified to suit the Finnish environment. SPBmod-method adheres to the ISO-standard quite closely. It was decided that heavy vehicles are not included in the test, as stipulated in the standard. The normalisation s...

  18. Precise plant height monitoring and biomass estimation with Terrestrial Laser Scanning in paddy rice

    Directory of Open Access Journals (Sweden)

    N. Tilly

    2013-10-01

    Full Text Available Optimizing crop management is a major topic in the field of precision agriculture as the growing world population puts pressure on the efficiency of field production. Accordingly, methods to measure plant parameters with the needed precision and within-field resolution are required. Studies show that Terrestrial Laser Scanning (TLS is a suitable method to capture small objects like crop plants. In this contribution, the results of multi-temporal surveys on paddy rice fields with the TLS system Riegl LMS-Z420i are presented. Three campaigns were carried out during the key vegetative stage of rice plants in the growing period 2012 to monitor the plant height. The TLS-derived point clouds are interpolated to visualize plant height above ground as crop surface models (CSMs with a high resolution of 0.01 m. Spatio-temporal differences within the data of one campaign and between consecutive campaigns can be detected. The results were validated against manually measured plant heights with a high correlation (R2 = 0.71. Furthermore, the dependence of actual biomass from plant height was evaluated. To the present, no method for the non-destructive determination of biomass is found yet. Thus, plant parameters, like the height, have to be used for biomass estimations. The good correlation (R2 = 0.66 leads to the assumption that biomass can be estimated from plant height measurements. The results show that TLS can be considered as a very promising tool for precision agriculture.

  19. Surface Catalysis and Oxidation on Stagnation Point Heat Flux Measurements in High Enthalpy Arc Jets

    Science.gov (United States)

    Nawaz, Anuscheh; Driver, David M.; Terrazas-Salinas

    2013-01-01

    Heat flux sensors are routinely used in arc jet facilities to determine heat transfer rates from plasma plume. The goal of this study is to assess the impact of surface composition changes on these heat flux sensors. Surface compositions can change due to oxidation and material deposition from the arc jet. Systematic surface analyses of the sensors were conducted before and after exposure to plasma. Currently copper is commonly used as surface material. Other surface materials were studied including nickel, constantan gold, platinum and silicon dioxide. The surfaces were exposed to plasma between 0.3 seconds and 3 seconds. Surface changes due to oxidation as well as copper deposition from the arc jets were observed. Results from changes in measured heat flux as a function of surface catalycity is given, along with a first assessment of enthalpy for these measurements. The use of cupric oxide is recommended for future heat flux measurements, due to its consistent surface composition arc jets.

  20. ESTIMATION OF STAND HEIGHT AND FOREST VOLUME USING HIGH RESOLUTION STEREO PHOTOGRAPHY AND FOREST TYPE MAP

    Directory of Open Access Journals (Sweden)

    K. M. Kim

    2016-06-01

    Full Text Available Traditional field methods for measuring tree heights are often too costly and time consuming. An alternative remote sensing approach is to measure tree heights from digital stereo photographs which is more practical for forest managers and less expensive than LiDAR or synthetic aperture radar. This work proposes an estimation of stand height and forest volume(m3/ha using normalized digital surface model (nDSM from high resolution stereo photography (25cm resolution and forest type map. The study area was located in Mt. Maehwa model forest in Hong Chun-Gun, South Korea. The forest type map has four attributes such as major species, age class, DBH class and crown density class by stand. Overlapping aerial photos were taken in September 2013 and digital surface model (DSM was created by photogrammetric methods(aerial triangulation, digital image matching. Then, digital terrain model (DTM was created by filtering DSM and subtracted DTM from DSM pixel by pixel, resulting in nDSM which represents object heights (buildings, trees, etc.. Two independent variables from nDSM were used to estimate forest stand volume: crown density (% and stand height (m. First, crown density was calculated using canopy segmentation method considering live crown ratio. Next, stand height was produced by averaging individual tree heights in a stand using Esri’s ArcGIS and the USDA Forest Service’s FUSION software. Finally, stand volume was estimated and mapped using aerial photo stand volume equations by species which have two independent variables, crown density and stand height. South Korea has a historical imagery archive which can show forest change in 40 years of successful forest rehabilitation. For a future study, forest volume change map (1970s–present will be produced using this stand volume estimation method and a historical imagery archive.

  1. Surface adhesion and its dependence on surface roughness and humidity measured with a flat AFM tip

    NARCIS (Netherlands)

    Colak, A.; Wormeester, Herbert; Zandvliet, Henricus J.W.; Poelsema, Bene

    2012-01-01

    The adhesion force between a surface and the tip of an atomic force microscope cantilever has been determined by recording force–distance curves with an atomic force microscope. Flat tips with a diameter of 2 μm were used to mimic the adhesion between two parallel surfaces. In such a configuration,

  2. Oxidation of clean silicon surfaces studied by four-point probe surface conductance measurements

    DEFF Research Database (Denmark)

    Petersen, Christian Leth; Grey, Francois; Aono, M.

    1997-01-01

    We have investigated how the conductance of Si(100)-(2 x 1) and Si(111)-(7 x 7) surfaces change during exposure to molecular oxygen. A monotonic decrease in conductance is seen as the (100) surfaces oxidizes. In contract to a prior study, we propose that this change is caused by a decrease in sur...

  3. Leidenfrost drops cooling surfaces: theory and interferometric measurement

    NARCIS (Netherlands)

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

    2017-01-01

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

  4. Measurement of grassland evaporation using a surface-layer ...

    African Journals Online (AJOL)

    A dual-beam surface-layer scintillometer (SLS) was used to estimate sensible heat flux (H) every 2 min for a path length of either 50 or 101 m, for more than 30 months in a mesic grassland in eastern South Africa. The SLS method relies on Monin-Obukhov similarity theory, the correlation between the laser beam signal ...

  5. The height of the atmospheric boundary layer during unstable conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gryning, S.E.

    2005-11-01

    The height of the convective atmospheric boundary layer, also called the mixed-layer, is one of the fundamental parameters that characterise the structure of the atmosphere near the ground. It has many theoretical and practical applications such as the prediction of air pollution concentrations, surface temperature and the scaling of turbulence. However, as pointed out by Builtjes (2001) in a review paper on Major Twentieth Century Milestones in Air Pollution Modelling and Its Application, the weakest point in meteorology data is still the determination of the height of the mixed-layer, the so-called mixing height. A simple applied model for the height of the mixed-layer over homogeneous terrain is suggested in chapter 2. It is based on a parameterised budget for the turbulent kinetic energy. In the model basically three terms - the spin-up term and the production of mechanical and convective turbulent kinetic energy - control the growth of the mixed layer. The interplay between the three terms is related to the meteorological conditions and the height of the mixed layer. A stable layer, the so-called entrainment zone, which is confined between the mixed layer and the free air above, caps the mixed layer. A parameterisation of the depth of the entrainment zone is also suggested, and used to devise a combined model for the height of the mixed layer and the entrainment zone. Another important aspect of the mixed layer development exists in coastal areas where an internal boundary layer forms downwind from the coastline. A model for the growth of the internal boundary layer is developed in analogy with the model for mixed layer development over homogeneous terrain. The strength of this model is that it can operate on a very fine spatial resolution with minor computer resources. Chapter 3 deals with the validation of the models. It is based in parts on data from the literature, and on own measurements. For the validation of the formation of the internal boundary layer

  6. Surface-source modeling and estimation using biomagnetic measurements.

    Science.gov (United States)

    Yetik, Imam Samil; Nehorai, Arye; Muravchik, Carlos H; Haueisen, Jens; Eiselt, Michael

    2006-10-01

    We propose a number of electric source models that are spatially distributed on an unknown surface for biomagnetism. These can be useful to model, e.g., patches of electrical activity on the cortex. We use a realistic head (or another organ) model and discuss the special case of a spherical head model with radial sensors resulting in more efficient computations of the estimates for magnetoencephalography. We derive forward solutions, maximum likelihood (ML) estimates, and Cramér-Rao bound (CRB) expressions for the unknown source parameters. A model selection method is applied to decide on the most appropriate model. We also present numerical examples to compare the performances and computational costs of the different models and illustrate when it is possible to distinguish between surface and focal sources or line sources. Finally, we apply our methods to real biomagnetic data of phantom human torso and demonstrate the applicability of them.

  7. Mapping Forest Canopy Height over Continental China Using Multi-Source Remote Sensing Data

    Directory of Open Access Journals (Sweden)

    Xiliang Ni

    2015-06-01

    Full Text Available Spatially-detailed forest height data are useful to monitor local, regional and global carbon cycle. LiDAR remote sensing can measure three-dimensional forest features but generating spatially-contiguous forest height maps at a large scale (e.g., continental and global is problematic because existing LiDAR instruments are still data-limited and expensive. This paper proposes a new approach based on an artificial neural network (ANN for modeling of forest canopy heights over the China continent. Our model ingests spaceborne LiDAR metrics and multiple geospatial predictors including climatic variables (temperature and precipitation, forest type, tree cover percent and land surface reflectance. The spaceborne LiDAR instrument used in the study is the Geoscience Laser Altimeter System (GLAS, which can provide within-footprint forest canopy heights. The ANN was trained with pairs between spatially discrete LiDAR metrics and full gridded geo-predictors. This generates valid conjugations to predict heights over the China continent. The ANN modeled heights were evaluated with three different reference data. First, field measured tree heights from three experiment sites were used to validate the ANN model predictions. The observed tree heights at the site-scale agreed well with the modeled forest heights (R = 0.827, and RMSE = 4.15 m. Second, spatially discrete GLAS observations and a continuous map from the interpolation of GLAS-derived tree heights were separately used to evaluate the ANN model. We obtained R of 0.725 and RMSE of 7.86 m and R of 0.759 and RMSE of 8.85 m, respectively. Further, inter-comparisons were also performed with two existing forest height maps. Our model granted a moderate agreement with the existing satellite-based forest height maps (R = 0.738, and RMSE = 7.65 m (R2 = 0.52, and RMSE = 8.99 m. Our results showed that the ANN model developed in this paper is capable of estimating forest heights over the China continent with a

  8. Measurement noise of a point autofocus surface topography instrument

    DEFF Research Database (Denmark)

    Feng, Xiaobing; Quagliotti, Danilo; Maculotti, Giacomo

    Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment.......Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment....

  9. PULSE HEIGHT ANALYZER

    Science.gov (United States)

    Johnstone, C.W.

    1958-01-21

    An anticoincidence device is described for a pair of adjacent channels of a multi-channel pulse height analyzer for preventing the lower channel from generating a count pulse in response to an input pulse when the input pulse has sufficient magnitude to reach the upper level channel. The anticoincidence circuit comprises a window amplifier, upper and lower level discriminators, and a biased-off amplifier. The output of the window amplifier is coupled to the inputs of the discriminators, the output of the upper level discriminator is connected to the resistance end of a series R-C network, the output of the lower level discriminator is coupled to the capacitance end of the R-C network, and the grid of the biased-off amplifier is coupled to the junction of the R-C network. In operation each discriminator produces a negative pulse output when the input pulse traverses its voltage setting. As a result of the connections to the R-C network, a trigger pulse will be sent to the biased-off amplifier when the incoming pulse level is sufficient to trigger only the lower level discriminator.

  10. The effect of scattered light sensor orientation on roughness measurement of curved polished surfaces

    DEFF Research Database (Denmark)

    Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

    2014-01-01

    Light scattering is a method for surface roughness measurements well suitable for use in a production environment thanks to its fast measurement rate, insensitivity to vibrations and to small misalignments. The method is however affected by several other factors. In this paper, the effect of angu...... of angular orientation of a commercial scattered light sensor on roughness measurements of polished cylindrical surfaces with crossed surface lay is investigated to document the robustness of the method....

  11. Measurement of the surface susceptibility and the surface conductivity of atomically thin by spectroscopic ellipsometry

    KAUST Repository

    Jayaswal, Gaurav

    2017-10-01

    We show how to correctly extract from the ellipsometric data the surface susceptibility and the surface conductivity that describe the optical properties of monolayer $\\ m MoS_2$. Theoretically, these parameters stem from modelling a single-layer two-dimensional crystal as a surface current, a truly two-dimensional model. Currently experimental practice is to consider this model equivalent to a homogeneous slab with an effective thickness given by the interlayer spacing of the exfoliating bulk material. We prove that the error in the evaluation of the surface susceptibility of monolayer $\\ m MoS_2$, owing to the use of the slab model, is at least 10% or greater, a significant discrepancy in the determination of the optical properties of this material.