Sample records for nadir angle results

  1. Optimal nadir scan angle for a space-based Doppler lidar wind sounder

    NASA Technical Reports Server (NTRS)

    Emmitt, George D.

    1991-01-01

    A Laser Atmospheric Wind Sounder computer simulation model was used to conduct a series of trades between scan angle and accuracy/coverage to determine the optimal scan angle for a space-based Doppler lidar wind sounder. Attention is given to vertical backscatter profiles, advanced signal processing, pulse length, shot density, and vertical velocity variance. The LOS speed uncertainty (m/s) projected into the horizontal plane as a function of the nadir scan angle for a single laser shot into the upper troposphere and lowest 1 km of the earth's atmosphere for expected backscatter values is shown.

  2. Sensitivity of off-nadir zenith angles to correlation between visible and near-infrared reflectance for use in remote sensing of aerosol over land

    Microsoft Academic Search

    Charles K. Gatebe; Michael D. King; Si-Chee Tsay; Q. Ji; G. Thomas Arnold; Jason Y. Li

    2001-01-01

    Cloud absorption radiometer (CAR) multispectral and multiangular data, collected during the Smoke, Clouds, and Radiation-Brazil (SCAR-B) Experiment, was used to examine the ratio technique, the official method for remote sensing of aerosols over land from the moderate resolution imaging spectroradiometer (MODIS) data, for view angles from nadir to 650 off-nadir. The strategy used is to first select a pristine, low

  3. A multi-frequency-multi-nadir-angle pushbroom-radiometer for oil spill detection and mapping (On the surface of the sea)

    NASA Astrophysics Data System (ADS)

    Salzer, D.; Birkmayer, W.; Braun, G.

    1987-03-01

    Scanning single-frequency radiometers have been used in the past to measure the thickness of oil layers. The proposed radiometer includes two improvements to the present systems. One is the use of the pushbroom concept where the scanning antenna is replaced by a multifeed antenna and the other improvement is the observation of the oil spill at two different angles to the surface. Since the differences in the radiometric temperatures of the water and the oil are a function of the observation angle the temperatures measured at different angles provide information about the oil type. The described system works simultaneously at two different frequencies to measure oil layers with thicknesses between 0.1 and 2.5 mm. So that both frequency channels simultaneously illuminate the same spots on the surface of the water dual-frequency horns are used.

  4. First results from a rotational Raman scattering cloud algorithm applied to the Suomi National Polar-orbiting Partnership (NPP) Ozone Mapping and Profiler Suite (OMPS) Nadir Mapper

    NASA Astrophysics Data System (ADS)

    Vasilkov, A.; Joiner, J.; Seftor, C.

    2014-09-01

    This paper reports initial results from an Ozone Mapping and Profiler Suite (OMPS) Nadir Mapper cloud pressure and cloud fraction algorithm. The OMPS cloud products are intended for use in OMPS ozone or other trace-gas algorithms. We developed the OMPS cloud products using a heritage algorithm developed for the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite. The cloud pressure algorithm utilizes the filling-in of ultraviolet solar Fraunhofer lines by rotational Raman scattering. The OMPS cloud products are evaluated by comparison with OMI cloud products that have been compared in turn with other collocated satellite data including cloud optical thickness profiles derived from a combination of measurements from the CloudSat radar and MODerate-resolution Imaging Spectroradiometer (MODIS). We find that the probability density functions (PDFs) of effective cloud fraction retrieved from OMPS and OMI measurements are very similar. The PDFs of the OMPS and OMI cloud pressures are comparable. However, OMPS retrieves somewhat higher pressures on average. The current NASA total ozone retrieval algorithm makes use of a monthly gridded cloud pressure climatology developed from OMI. This climatology captures much of the variability associated with the relevant cloud pressures. However, the use of actual cloud pressures retrieved with OMPS in place of the OMI climatology changes OMPS total column ozone estimates locally (presumably in the correct direction) only in areas with large differences between climatological and actual cloud pressures. The ozone differences can be up to 5% in such areas.

  5. Nadir measurements of carbon monoxide distributions by the Tropospheric Emission Spectrometer instrument onboard the Aura Spacecraft: Overview of analysis approach and examples of initial results

    Microsoft Academic Search

    Curtis P. Rinsland; Ming Luo; Jennifer A. Logan; Reinhard Beer; Helen Worden; Susan S. Kulawik; David Rider; Greg Osterman; Michael Gunson; Annmarie Eldering; Aaron Goldman; Mark Shephard; Shepard A. Clough; Clive Rodgers; Michael Lampel; Linda Chiou

    2006-01-01

    We provide an overview of the nadir measurements of carbon monoxide (CO) obtained thus far by the Tropospheric Emission Spectrometer (TES). The instrument is a high resolution array Fourier transform spectrometer designed to measure infrared spectral radiances from low Earth orbit. It is one of four instruments successfully launched onboard the Aura platform into a sun synchronous orbit at an

  6. Monitoring the Terra and Aqua MODIS RSB calibration using scattered light from the Nadir-port

    NASA Astrophysics Data System (ADS)

    Angal, Amit; Xiong, Xiaoxiong; Geng, Xu; Sun, Junqiang

    2014-09-01

    MODIS is currently onboard NASA's EOS Terra and Aqua spacecraft launched on December 18, 1999 and May 4, 2002, respectively. MODIS reflective solar bands (RSB) are calibrated on-orbit using solar illumination reflected from its onboard solar diffuser (SD). The solar diffuser stability monitor (SDSM) is designed to track the on-orbit degradation of the SD via alternate observations of the Sun and SD. A wavelength-dependent degradation pattern is observed for both MODIS instruments with a faster degradation rate observed at shorter wavelengths. The UV exposure of the SD to sunlight and the scattered light (the sunlight reflected from top of the atmosphere) through the instrument nadir port contributes to its reflectance degradation. The scatter off the diffuser onto the scan mirror is in the forward direction, whereas the scatter off the diffuser onto the SDSM scan mirror is in the backward direction. Since the outgoing angles (viewed by MODIS detectors) are the same as the scheduled SD calibration, the gain derived from scattering light facilitates monitoring the dependence on SD degradation on incident angles. A methodology is formulated to track the MODIS SD degradation using scattered light through the nadir-port and comparing the result with the SD degradation as measured by the SDSM. In this study, multiple orbits from a given day of each month are processed to obtain a SD response to the nadir-port illumination. Results show that a reasonable agreement is observed between the SD degradation estimates derived from both view-angles.

  7. Recent Results on the CKM Angle Alpha

    SciTech Connect

    Mihalyi, A.; /Wisconsin U., Madison

    2005-10-18

    The method to measure the CKM angle {alpha} and the modes sensitive to it are discussed. It is shown that the B {yields} {rho}{rho} decays provide the most stringent constraint on {alpha}, which is found to be {alpha} = 96{sup o} {+-} 10{sup o}(stat) {+-} 4{sup o}(syst){+-} 13{sup o}(penguin).

  8. Angles

    NSDL National Science Digital Library

    Jo Edkins

    2007-01-01

    This set of eight interactive activities lets the user explore angles from many different perspectives. Activities include (1) visualizing the size of an angle; (2) examining objects that will stand or fall with right and non-right angles; (3) identifying obtuse, right, acute and straight angles; (4) guessing angle measures with different levels of precision; (5) exploring regular shapes and their angle measures; (6) studying angles in a fractal tree that is drawn with user inputs of the same angle measure between the branches at each stage; (7) exploring angle measures through firing a cannon (8) drawing with a Logo activity.

  9. Angles

    NSDL National Science Digital Library

    Practice your knowledge of acute, obtuse, and alternate angles. Also, practice relationships between angles - vertical, adjacent, alternate, same-side, and corresponding. Angles is one of the Interactivate assessment explorers.

  10. Brook Trout Angling in Maine 2009 Survey Results

    E-print Network

    Thomas, Andrew

    Brook Trout Angling in Maine 2009 Survey Results Marc Edwards University of Maine Cooperative Extension Franklin County Office A Cooperative Project between the University of Maine Cooperative Extension and Maine Department of Inland Fisheries and Wildlife #12;2 Background In a meeting at University of Maine

  11. Angles

    NSDL National Science Digital Library

    Shodor Education Foundation

    2004-01-01

    This Java applet enables students to investigate acute, obtuse, and right angles. The student decides to work with one or two transversals and a pair of parallel lines. Angle measure is given for one angle. The student answers a short series of questions about the size of other angles, identifying relationships such as vertical and adjacent angles and alternate interior and alternate exterior angles. In addition to automatically checking the student's answers, the applet can keep score of correct answers. From the activity page, What, How, and Why buttons open pages that explain the activity's purpose, function, and how the mathematics fits into the curriculum. Supplemental resources include lesson plans and a handout with a grid for showing the relationship between all possible angles that occur when parallel lines are cut by a transversal. Copyright 2005 Eisenhower National Clearinghouse

  12. Nadir vector modeling for the spacecraft and its engineering implementation

    NASA Astrophysics Data System (ADS)

    Liu, Hong-xing; Shen, Gong-xun; Lin, Wang-peng; Xu, Jian-feng

    2011-08-01

    Attitude control and determination along with the fix and navigation of the spacecraft is the fundamental functional elements in the space scientific research tasks. Nadir vector is usually applied in the attitude determination of spacecraft relative to the Earth, and it is also commonly used as a reference vector in autonomous navigation especially in the satellites' preliminary coarse orbit determination. In the paper, we begin with the shape of the Earth as seen from the space, which is defined by the Earth horizon as seen from the position of the observer. The geometric model of the nadir vector pointing from the spacecraft to the Earth center is established basing on three-dimension earth spheroid model; the effect of Earth flattening on the attitude determination and positioning is discussed, the flattening and irregularity of the Earth ultraviolet layer model are the major error sources resulting in poor accuracy of attitude determination and fix. An error modification method is presented to compensate for the Earth flattening error. Several crucial techniques in determining earth center and nadir vector basing on CCD sensor are stressed in the paper. Noise elimination and image processing means are introduced to restraint the influences of harmful signals in the image acquisitions; edge detection is one of the most important aspects in the process of determining the Earth center, Randomed Hough Transformation method and least square method are effective way to check the edge of earth horizon profile.

  13. Using Microwave and Infrared Radiances from Off-Nadir Pixels: Application of Radiative Transfer to Slanted Line-of-Sight and Comparisons with NASA EOS Aqua Data

    NASA Technical Reports Server (NTRS)

    Poli, Paul; Joiner, Joanna

    2005-01-01

    The passive infrared and microwave nadir sounders such as (A)TOVS observe the atmosphere from a polar orbit by directing their scan pointed at the ground up to about 49 degrees from nadir. Except for the pixels located right on the satellite ground track, the radiance measurements collected by these instruments characterize hence atmospheric emission paths which are slanted with respect to the zenithal direction at the ground. At the outer swath edges, the deviations from nadir reach about 60 degrees in terms of Satellite Zenith Angle (SZA). The radiative transfer codes used in operational Numerical Weather Prediction applications make the appropriate corrections to account for the extra path induced by the non-zero SZA. However, no corrections are made to account for the fact that the atmospheric profiles along the slanted line-of-sight (LOS) are different from the vertical because of horizontal gradients in the atmosphere. Using NASA EOS Aqua satellite's orbits, zenith and azimuth angles, as well as three-dimensional fields of temperature, water vapor, and ozone produced by the NASA Global Modeling and Assimilation Office, we extracted slanted atmospheric profiles for actual soundings performed by the AIRS and AMSU-A instruments onboard EOS Aqua. We will present the results of our study comparing the calculated brightness temperatures along slanted LOS and vertical LOS with AIRS and AMSU-A observations.

  14. NADIR: A Flexible Archiving System Current Development

    NASA Astrophysics Data System (ADS)

    Knapic, C.; De Marco, M.; Smareglia, R.; Molinaro, M.

    2014-05-01

    The New Archiving Distributed InfrastructuRe (NADIR) is under development at the Italian center for Astronomical Archives (IA2) to increase the performances of the current archival software tools at the data center. Traditional softwares usually offer simple and robust solutions to perform data archive and distribution but are awkward to adapt and reuse in projects that have different purposes. Data evolution in terms of data model, format, publication policy, version, and meta-data content are the main threats to re-usage. NADIR, using stable and mature framework features, answers those very challenging issues. Its main characteristics are a configuration database, a multi threading and multi language environment (C++, Java, Python), special features to guarantee high scalability, modularity, robustness, error tracking, and tools to monitor with confidence the status of each project at each archiving site. In this contribution, the development of the core components is presented, commenting also on some performance and innovative features (multi-cast and publisher-subscriber paradigms). NADIR is planned to be developed as simply as possible with default configurations for every project, first of all for LBT and other IA2 projects.

  15. Bidirectional measurements of surface reflectance for view angle corrections of oblique imagery

    NASA Technical Reports Server (NTRS)

    Jackson, R. D.; Teillet, P. M.; Slater, P. N.; Fedosejevs, G.; Jasinski, Michael F.

    1990-01-01

    An apparatus for acquiring bidirectional reflectance-factor data was constructed and used over four surface types. Data sets were obtained over a headed wheat canopy, bare soil having several different roughness conditions, playa (dry lake bed), and gypsum sand. Results are presented in terms of relative bidirectional reflectance factors (BRFs) as a function of view angle at a number of solar zenith angles, nadir BRFs as a function of solar zenith angles, and, for wheat, vegetation indices as related to view and solar zenith angles. The wheat canopy exhibited the largest BRF changes with view angle. BRFs for the red and the NIR bands measured over wheat did not have the same relationship with view angle. NIR/Red ratios calculated from nadir BRFs changed by nearly a factor of 2 when the solar zenith angle changed from 20 to 50 degs. BRF versus view angle relationships were similar for soils having smooth and intermediate rough surfaces but were considerably different for the roughest surface. Nadir BRF versus solar-zenith angle relationships were distinctly different for the three soil roughness levels. Of the various surfaces, BRFs for gypsum sand changed the least with view angle (10 percent at 30 degs).

  16. Preliminary Results of the Extreme Ultraviolet Explorer Right Angle Program

    NASA Astrophysics Data System (ADS)

    McDonald, K.; Craig, N.; Sirk, M. M.; Drake, J. J.; Malina, R. F.

    1993-12-01

    During the guest observer phase of the EUVE Mission, data are being collected with the survey scanners and the Deep Survey Scanner. The EUVE Right Angle Program (RAP) involves the analysis of this data set and the coordination of possible simultaneous observations with ground based instruments. This data set consists of several discrete pointings performed at a much deeper level than the previous EUVE all-sky survey, although covering only a few percent of the sky. Analysis of this data set has detected a large number of previously undetected EUV sources. We present here a preliminary list of the sources observed during the EUVE Right Angle Program and compare properties of this list with properties of the EUVE Bright Source List. This work has been supported by NASA contract NAS5--30180.

  17. Angled Injection: Turbulent Flow Hybrid Bearings Comparison to Test Results

    NASA Technical Reports Server (NTRS)

    SanAndres, Luis; Childs, Dara

    1997-01-01

    Hydrostatic/hydrodynamic (hybrid) journal bearings handling process liquids have limited dynamic stability characteristics and their application as support elements to high speed flexible rotating systems is severely restricted. Measurements on water hybrid bearings with angled orifice injection have demonstrated improved rotordynamic performance with virtual elimination of cross-coupled stiffness coefficients and null or negative whirl frequency ratios. A bulk-flow model for prediction of the static performance and force coefficients of hybrid bearings with angled orifice injection is advanced. The analysis reveals that the fluid momentum exchange at the orifice discharge produces a pressure rise in the hydrostatic recess retards the shear flow induced by journal rotation, and thus, reduces cross-coupling forces. The predictions from the model are compared with experimental measurements for a 45 deg. angled orifice injection, 5 recess water hybrid bearing operating at 10.2, 17.4, and 24.6 krpm and with supply pressures of 4, 5.5, and 7 MPa. The correlations include recess pressures, flow rates, and rotordynamic force coefficients at the journal centered position.

  18. An improved tropospheric ozone database retrieved from SCIAMACHY Limb-Nadir-Matching method

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Rozanov, Alexei; Ladstätter-Weißenmayer, Annette; Ebojie, Felix; Rahpoe, Nabiz; Bötel, Stefan; Burrows, John

    2015-04-01

    Tropospheric ozone is one of the most important green-house gases and the main component of photochemical smog. It is either transported from the stratosphere or photochemically produced during pollution events in the troposphere that threaten the respiratory system. To investigate sources, transport mechanisms of tropospheric ozone in a global view, limb nadir matching (LNM) technique applied with SCIAMACHY instrument is used to retrieve tropospheric ozone. With the fact that 90% ozone is located in the stratosphere and only about 10% can be observed in the troposphere, the usage of satellite data requires highly qualified nadir and limb data. In this study we show an improvement of SCIAMACHY limb data as well as its influence on tropospheric ozone results. The limb nadir matching technique is also refined to increase the quality of the tropospheric ozone. The results are validated with ozone sonde measurements.

  19. Post-launch performance evaluation of the OMPS Nadir Mapper and Nadir Profiler

    NASA Astrophysics Data System (ADS)

    Grotenhuis, Michael G.; Wu, Xiangqian; Flynn, Larry; Beach, Eric; Niu, Jianguo; Yu, Wei

    2014-09-01

    The Joint Polar Satellite System (JPSS) represents the latest generation of polar-orbiting satellites operated by the National Oceanic and Atmospheric Administration (NOAA). The first in the JPSS series of satellites, the Suomi National Polar-orbiting Partnership (NPP) spacecraft was launched in November 2011 to bridge the gap between the current Polar Operational Environmental Satellites (POES) and the future JPSS-1. The Ozone Mapping Profiler Suite (OMPS) is a suite of hyperspectral instruments onboard the Suomi NPP spacecraft designed to continue atmospheric ozone records through both atmospheric profiles and global distribution mapping. OMPS will also be included on the future JPSS payloads. In order to properly extend measurements from previous ozone instruments, including the Solar Backscatter Ultraviolet (SBUV) instrument on POES, proper OMPS calibration is necessary. In this study, the postlaunch performance of the OMPS Nadir Mapper (NM) and Nadir Profiler (NP) are evaluated through their Sensor Data Records (SDRs), which validates their end-to-end calibration. This is achieved through stability monitoring and intercomparison.

  20. An Evolutionary Algorithm to Estimate the Nadir Point in MOLP

    Microsoft Academic Search

    Maria João Alves; João Paulo Costa

    2009-01-01

    In this paper we propose an evolutionary algorithm to estimate the minimum (nadir) objective values over the efficient set in multiple objective linear programming problems (MOLP). Nadir values provide valuable\\u000a information for characterizing the ranges of the objective function values over the efficient set. However, they are very\\u000a hard to compute in the general case. The proposed algorithm uses a

  1. The dipole tilt angle dependence of the bow shock for southward IMF: MHD results

    NASA Astrophysics Data System (ADS)

    Wang, M.; Lu, J. Y.; Yuan, H. Z.; Kabin, K.; Liu, Z.-Q.; Zhao, M. X.; Li, G.

    2015-02-01

    The location and shape of the Earth's bow shock depend on the properties of the upstream solar wind, as well as the size and shape of the downstream magnetopause. Many studies have suggested that the influence of the dipole tilt angle on the magnetopause is significant, especially at the high-latitude region, however, to date there is no bow shock model which depends on the dipole tilt angle. Using a physics-based global magnetohydrodynamic (MHD) model, the Space Weather Modeling Framework (SWMF), we investigate the effect of the dipole tilt angle on the location and shape of the bow shock, and our results show that (1) the subsolar standoff distance and the north-south asymmetry of bow shock increase with the increasing dipole tilt angle; (2) with the dipole tilt angle positively increasing, the flaring angle of the bow shock increases in the northern hemisphere but keeps almost unchanged in the southern hemisphere, and the rotational asymmetry slightly decreases in the northern hemisphere and rapidly decreases in the southern hemisphere; and (3) the influence of dipole tilt angle on the shape of the bow shock is north-south symmetric.

  2. Hypofractionated SBRT versus conventionally fractionated EBRT for prostate cancer: comparison of PSA slope and nadir

    PubMed Central

    2014-01-01

    Background Patients with early stage prostate cancer have a variety of curative radiotherapy options, including conventionally-fractionated external beam radiotherapy (CF-EBRT) and hypofractionated stereotactic body radiotherapy (SBRT). Although results of CF-EBRT are well known, the use of SBRT for prostate cancer is a more recent development, and long-term follow-up is not yet available. However, rapid post-treatment PSA decline and low PSA nadir have been linked to improved clinical outcomes. The purpose of this study was to compare the PSA kinetics between CF-EBRT and SBRT in newly diagnosed localized prostate cancer. Materials/methods 75 patients with low to low-intermediate risk prostate cancer (T1-T2; GS 3?+?3, PSA?70.2 Gy, <76 Gy) to the prostate only, were identified from a prospectively collected cohort of patients treated at the University of California, San Francisco (1997–2012). Patients were excluded if they failed therapy by the Phoenix definition or had less than 1 year of follow-up or <3 PSAs. 43 patients who were treated with SBRT to the prostate to 38 Gy in 4 daily fractions also met the same criteria. PSA nadir and rate of change in PSA over time (slope) were calculated from the completion of RT to 1, 2 and 3 years post-RT. Results The median PSA nadir and slope for CF-EBRT was 1.00, 0.72 and 0.60 ng/ml and -0.09, -0.04, -0.02 ng/ml/month, respectively, for durations of 1, 2 and 3 years post RT. Similarly, for SBRT, the median PSA nadirs and slopes were 0.70, 0.40, 0.24 ng and -0.09, -0.06, -0.05 ng/ml/month, respectively. The PSA slope for SBRT was greater than CF-EBRT (p?nadir was significantly lower for SBRT when compared to EBRT for years 2 and 3 (p?nadir and greater rate of decline in PSA 2 and 3 years following completion of RT than with CF-EBRT, consistent with delivery of a higher bioequivalent dose. Although follow-up for SBRT is limited, the improved PSA kinetics over CF-EBRT are promising for improved biochemical control. PMID:24484652

  3. Postlaunch performance of the Suomi National Polar-orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) nadir sensors

    NASA Astrophysics Data System (ADS)

    Seftor, C. J.; Jaross, G.; Kowitt, M.; Haken, M.; Li, J.; Flynn, L. E.

    2014-04-01

    The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long-term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected.

  4. Postlaunch Performance of the Suomi National Polar-Orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) Nadir Sensors

    NASA Technical Reports Server (NTRS)

    Seftor, C. J.; Jaross, G.; Kowitt, M.; Haken, M.; Li, J.; Flynn, L. E.

    2014-01-01

    The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long-term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected.

  5. NADIR (Network Anomaly Detection and Intrusion Reporter): A prototype network intrusion detection system

    SciTech Connect

    Jackson, K.A.; DuBois, D.H.; Stallings, C.A.

    1990-01-01

    The Network Anomaly Detection and Intrusion Reporter (NADIR) is an expert system which is intended to provide real-time security auditing for intrusion and misuse detection at Los Alamos National Laboratory's Integrated Computing Network (ICN). It is based on three basic assumptions: that statistical analysis of computer system and user activities may be used to characterize normal system and user behavior, and that given the resulting statistical profiles, behavior which deviates beyond certain bounds can be detected, that expert system techniques can be applied to security auditing and intrusion detection, and that successful intrusion detection may take place while monitoring a limited set of network activities such as user authentication and access control, file movement and storage, and job scheduling. NADIR has been developed to employ these basic concepts while monitoring the audited activities of more than 8000 ICN users.

  6. Effects of the Angle Between the Density Gradient and the External Magnetic Field on the Linear Mode Conversion and Resultant Beaming Angle of LO-Mode Radio Emissions

    NASA Astrophysics Data System (ADS)

    Kalaee, Mohammad Javad; Katoh, Yuto; Ono, Takayuki

    2014-11-01

    Recent spacecraft's observations of kilometric continuum radiation showed that the linear mode conversion theory (LMCT) cannot explain the beaming angle of these observations; on the other hand satellite observations show some local fluctuation in the density gradient. In this research, we consider the mode conversion process from UHR-mode (slow Z- mode) to LO-mode (ordinary) waves, focusing on the effect of the angle between the density gradient and the external magnetic field on the efficiency of the LMCT and the resultant beaming angle of converted LO-mode waves; a comparison of the LMCT and simulation results are presented. We first consider a condition that the density gradient is perpendicular to the external magnetic field, corresponding to the condition assumed in the conventional LMCT. Next, we extend the discussion to the condition that the density gradient is oblique to the external magnetic field. Our aim here is to investigate a condition where the efficient mode conversion can occur and to study the deviation of the beaming angle from that estimated by LMCT. From the results of analyses, for both perpendicular and oblique cases, the highest conversion efficiency is obtained for a certain value of the wave normal angle (critical wave normal angle) of the incident slow Z-mode waves, corresponding to the case when two mode branches are matched. The simulation results show in the perpendicular case that the beaming angle is consistent with the conventional LMCT; but in the oblique case a critical wave normal angle becomes different from the perpendicular case and the beaming angle is different from the LMCT prediction.

  7. Interpreting vegetation reflectance measurements as a function of solar zenith angle

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Smith, J. A.; Ranson, K. J.

    1979-01-01

    Spectral hemispherical-conical reflectances of a nadir looking sensor were taken throughout the day for a lodgepole pine and two grass canopies. Mathematical simulations of both spectral hemispherical-conical and bi-hemispherical reflectances were performed for two theoretical canopies of contrasting geometric structure. These results and comparisons with literature studies showed a great amount of variability of vegetation canopy reflectances as a function of solar zenith angle. Explanations for this variability are discussed and recommendations for further measurements are proposed.

  8. Piecewise linear car-following modeling Nadir Farhi

    E-print Network

    Boyer, Edmond

    Piecewise linear car-following modeling Nadir Farhi Universit´e Paris-Est, IFSTTAR, GRETTIA, F-93166 Noisy-le-Grand, France. Abstract We present a traffic model that extends the linear car-time car-dynamics describing the traffic on a 1-lane road without passing is interpreted as a dynamic

  9. Nadir looking airborne radar and possible applications to forestry

    Microsoft Academic Search

    R. Bernard; M. E. Frezal; D. Vidal-Madjar; D. Guyon; J. Riom

    1987-01-01

    It is shown that investigators can use an airborne radar with high range resolution to measure the height and planting density of trees in forests. Based on C-band, nadir looking airborne radar data from a site in Southwest France, a single-scattering model is developed and verified to aid in the interpretation of such data.

  10. Nadir Sounding of Carbon Gases using SCIAMACHY Near Infrared Channels

    NASA Astrophysics Data System (ADS)

    Gimeno García, Sebastián; Schreier, Franz; Lichtenberg, Günter; Slijkhuis, Sander; Hess, Michael; Aberle, Bernd

    The Beer InfraRed Retrieval Algorithm (BIRRA) and Column EstimatoR Vertical InfraRed Sounding Atmosphere (CERVISA) codes have been designed to retrieve vertical column den-sities (VCDs) of atmospheric gases in the near and thermal infrared (NIR,TIR) region of the electromagnetic spectrum by means of non-linear least squares fitting of radiances. As part of the operational SCIAMACHY level 1-2 processor, BIRRA is currently used for the specific retrieval of carbon monoxide (CO) VCDs exploiting the fitting window 4282-4301 cm-1 within the SCIAMACHY channel 8. Using appropriate fitting windows in channel 6, BIRRA also allows to gain information on greenhouse gases such as methane and carbon dioxide. Unfortunately, the increasing number of dead and bad pixels -specially in the NIR channels -reduces the available spectral information and consequently makes the VCDs retrieval more and more challenging. The proper choice of the pixel mask, fitting window, auxiliary fit parameters, as well as the filtering of the Level 2 data is crucial for obtaining a high quality atmospheric product. For validation of BIRRA the closely related CERVISA code is used to retrieve CO and CH4 from nadir infrared sounding data of AIRS, IASI, or TES. BIRRA and CERVISA share a large portion of modules, e.g., for line-by-line absorption and the nonlinear least squares solver; the essential difference is the part of the forward model devoted to radiative transfer through the atmosphere, i.e., Beer's law for the NIR versus Schwarzschild's equation for the TIR. CERVISA retrieval results are compared both to the operational products of the TIR sounder and to the SCIAMACHY-BIRRA product. In this work, we present recent results of carbon monoxide and methane retrievals.

  11. PROSTATE SPECIFIC ANTIGEN NADIR ACHIEVED BY MEN APPARENTLY CURED OF PROSTATE CANCER BY RADIOTHERAPY

    Microsoft Academic Search

    FRANK A. CRITZ; A. KEITH LEVINSON; W. HAMILTON WILLIAMS; CLINTON T. HOLLADAY; VIVIAN D. GRIFFIN; DAVID A. HOLLADAY

    1999-01-01

    PurposeThe role of prostate specific antigen (PSA) nadir in the definition of disease freedom after radiotherapy of prostate cancer is controversial. We evaluate post-irradiation PSA nadir in men apparently cured of this disease.

  12. Western Nankai Trough seismogenic zone: Results from a wide-angle ocean bottom seismic survey

    Microsoft Academic Search

    Shuichi Kodaira; Narumi Takahashi; Jin-Oh Park; Kimihiro Mochizuki; Masanao Shinohara; Shozo Kimura

    2000-01-01

    The Nankai Trough, southwestern Japan, is recognized as a vigorous seismogenic zone with well-studied historic earthquakes. This paper presents results of a wide-angle ocean bottom seismographs (OBS) study at the western Nankai Trough seismogenic zone. The OBS data used were acquired on a profile (250 km long) across the presumed coseismic slip zone of the 1946 Nankaido earthquake (Ms=8.2). The

  13. Using Multi-angle Data to Characterize Natural Hazards: Results From MISR

    NASA Astrophysics Data System (ADS)

    Hunt, L. A.

    2005-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) instrument provides a unique view of Earth, obtaining precisely calibrated images taken simultaneously at nine different angles and four wavelengths to produce radiance, aerosol, cloud and land surface data. MISR was launched on December 18, 1999 on the NASA Earth Observing System (EOS) Terra satellite. MISR imagery created from the Level 1 radiance data and derived quantities from the Level 2 aerosol, surface, and cloud products provide added information about natural hazards such as hurricanes, fires, floods, dust storms, and the December 2004 tsunami by exploiting both the radiometric and geometric information that are extracted from its multi-angular views. This angular perspective makes possible viewing techniques such as stereo anaglyph images and time-lapse animation to provide additional insight into characterizing these events. Better measurements can be made of parameters such as cloud height and albedo, smoke plume height, and aerosol type and height. Examples of results from MISR highlighting the value of multi-angle data will be shown. MISR data are processed, archived and distributed by the NASA Langley Atmospheric Sciences Data Center (ASDC). Data, information and tools are available at the ASDC web site, http://eosweb.larc.nasa.gov.

  14. Mjølnir Crater as a Result of Oblique Impact: Asymmetry Evidence Constrains Impact Direction and Angle

    Microsoft Academic Search

    Filippos Tsikalas

    2005-01-01

    The 40-km-diameter Mjølnir crater is proposed to have resulted from an oblique impact from the south\\/southwest direction and\\u000a at a ~45° (possibly 30°–45°) angle from the horizontal. This is substantiated by several diagnostic structural and geophysical\\u000a signatures related to obliquity and revealed through detailed re-assessment of Mjølnir’s well-established structure, morphology,\\u000a and gravity and seismic velocity anomalies. The diagnostic signatures include:

  15. [Study of hyperspectral polarized reflectance of vegetation canopy at nadir viewing direction].

    PubMed

    L?, Yun-Feng

    2013-04-01

    In the present study, corn canopy is the objective. Firstly the polarization of corn canopy was analyzed based on polarization reflection mechanism; then, the polarization of canopy was measured in different growth period at nadir before heading. The result proved the theoretical derivation that the light reflected from corn canopy is polarized, and found that in the total reflection the polarization light accounts for up to 10%. This shows that polarization measurement provides auxiliary information for remote sensing, but also illustrates that the use of the polarization information retrieval of atmospheric parameters should be considered when the surface polarization affects on it. PMID:23841422

  16. Structured water in polyelectrolyte dendrimers: Understanding small angle neutron scattering results through atomistic simulation

    SciTech Connect

    Chen, Wei-Ren [ORNL; Do, Changwoo [ORNL; Hong, Kunlun [ORNL; Liu, Emily [Rensselaer Polytechnic Institute (RPI); Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST); Smith, Gregory Scott [ORNL; Wu, Bin [ORNL; Egami, T [University of Tennessee, Knoxville (UTK); Smith, Sean C [ORNL

    2012-01-01

    Based on atomistic molecular dynamics (MD) simulations, the small angle neutron scattering (SANS) intensity behavior of a single generation-4 (G4) polyelectrolyte polyamidoamine (PAMAM) starburst dendrimer is investigated at different levels of molecular protonation. The SANS form factor, P(Q), and Debye autocorrelation function, (r), are calculated from the equilibrium MD trajectory based on a mathematical approach proposed in this work which provides a link between the neutron scattering experiment and MD computation. The simulations enable scattering calculations of not only the hydrocarbons, but also the contribution to the scattering length density fluctuations caused by structured, confined water within the dendrimer. Based on our computational results, we question the validity of using radius of gyration RG for microstructure characterization of a polyelectrolyte dendrimer from the scattering perspective.

  17. Computer communications through telecommunications satellite systems - The NADIR project

    NASA Astrophysics Data System (ADS)

    Grange, J.-L.

    Current developments in satellite digital communication in Europe are surveyed, and the status of the French NADIR project begun in 1980 is reported. The geographic coverage, transmission rates, propagation delays, broadcasting and multidestination channels, and error rates characteristic of present satellite systems are discussed, and the specific performance parameters of the Telecom-1 system, comprising three geosynchronous satellites (one operational and two backup) with six 25-Mbit/sec, 12-14-GHz digital transponders and one 4-6 GHz analog port (for telephone and TV services) each, are examined. Telecom-1 will operate in a TDMA-AD mode with coverage of up to 320 earth stations in Central and Western Europe, transmission rates of 2.4-2000 kbit/sec, and error rates less than 10 to the -6th during 99 percent of the time. New applications foreseen include remote processing, distributed databases, computer teleconferencing, and electronic mail systems; new basic tools such as bulk-transfer and transaction-transfer protocols and database-management systems will be required. These tools are under development and testing (using the ANIS Telecom-1 simulator) by NADIR.

  18. The impact of ozone field horizontal inhomogeneities on nadir-viewing orbital backscatter UV measurements

    NASA Technical Reports Server (NTRS)

    Mueller, Martin D.; Poli, Paul; Joiner, Joanna

    2005-01-01

    Radiative transfer calculations for nadir-viewing satellites normally assume the atmosphere to be horizontally homogeneous. Yet it has been shown recently that horizontal gradients can lead to significant errors in satellite infrared and microwave soundings. We extend the methodology to backscatter ultra-violet observations of ozone, and present a first estimate of the effect s magnitude. The Solar Backscatter Ultra-Violet/2 (SBUV/2) instrument, a pure nadir sounder, serves as our test bed. Our results indicate that in a vast majority of cases the abovementioned errors can be neglected. However, occurrence of higher errors, particularly at wavelengths longer than 300 nm, coincides with some of the most interesting atmospheric phenomena like tropopause folds and the South polar ozone hole. This leads to a seasonal variation of the magnitude of the effect. Due to the mostly zonal geometry of the ozone distribution, there is also the possibility that biases may be introduced, which is particularly critical if the data are to be assimilated or used to determine trends. The results presented are tested for robustness using different model atmospheres. The influence of horizontal inhomogeneities will be even more pronounced for cross-track sounders and limb viewers, and easier to detect once higher resolution atmospheric models are available. This will be investigated in future studies.

  19. NPP VIIRS and Aqua MODIS RSB comparison using observations from simultaneous nadir overpasses (SNO)

    NASA Astrophysics Data System (ADS)

    Wu, Aisheng; Xiong, Xiaoxiong

    2012-09-01

    Suomi NPP (National Polar-orbiting Partnership) satellite (http://npp.gsfc.nasa.gov/viirs.html) began to daily collect global data following its successful launch on October 28, 2011. The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key NPP sensor. Similar to the design of the OLS, SeaWiFS and MODIS instruments, VIIRS has on-board calibration components including a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) for the reflective solar bands (RSB), a V-groove blackbody for the thermal emissive bands (TEB), and a space view (SV) port for background subtraction. Immediately after the VIIRS nadir door's opening on November 21, 2011, anomalously large degradation in the SD response was identified in the near-IR wavelength region, which was unexpected as decreases in the SD reflectance usually occur gradually in the blue (~0.4 ?m) wavelength region based on past experience. In this study, we use a well-calibrated Aqua MODIS as reference to track and evaluate VIIRS RSB stability and performance. Reflectances observed by both sensors from simultaneous nadir overpasses (SNO) are used to determine VIIRS to MODIS reflectance ratios for their spectral matching bands. Results of this study provide an immediate post-launch assessment, independent validation of the anomalous degradation observed in SD measurements at near-IR wavelengths and initial analysis of calibration stability and consistency.

  20. Precipitation measurement using SIR-C: A feasibility study. Investigation at nadir

    NASA Technical Reports Server (NTRS)

    Ahamad, Atiq; Moore, Richard K.

    1993-01-01

    The most significant limitation of the imaging SAR in rain measurements is the ground return coupled to the rain cell. Here we report a study of the possibility of using the X-SAR and the C-band channel of SIR-C for rain measurement. Earlier signal-to-clutter calculations rule out the use of X-SAR at steeper off-vertical angles of incidence (i.e., 20 less than theta less than 50). Only rain rates greater than 30 mm/hr at angles of incidence greater than 60 degrees showed good signal-to-clutter ratio (SCR). This study involved calculations at vertical incidence. There is adequate signal-to-noise ratio (SNR) at vertical incidence, but the presence of high-range side-lobe levels leads to small SCR for measurement over oceans at both X and C bands. For larger rain thickness (greater than two km), the SCR gets better and smaller rain rates (greater than 10 mm/hr) can be measured. However, rain measurements over forests seem to be feasible at nadir even for smaller rain thickness (less than two km). We conclude that X band may be usable over the forest at vertical incidence to measure rain rates greater than five mm/hr even for shallow rain thickness and over ocean for large rain thickness.

  1. Computerized data reduction techniques for nadir viewing remote sensors

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Gormsen, Barbara B.

    1985-01-01

    Computer resources have been developed for the analysis and reduction of MAPS experimental data from the OSTA-1 payload. The MAPS Research Project is concerned with the measurement of the global distribution of mid-tropospheric carbon monoxide. The measurement technique for the MAPS instrument is based on non-dispersive gas filter radiometer operating in the nadir viewing mode. The MAPS experiment has two passive remote sensing instruments, the prototype instrument which is used to measure tropospheric air pollution from aircraft platforms and the third generation (OSTA) instrument which is used to measure carbon monoxide in the mid and upper troposphere from space platforms. Extensive effort was also expended in support of the MAPS/OSTA-3 shuttle flight. Specific capabilities and resources developed are discussed.

  2. TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 x 8.5 km nadir ... Data: TES Order Tool Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  3. TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.2 x 8.5 km nadir ... Data: TES Order Tool Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  4. TES/Aura L2 Carbon Dioxide (CO2) Lite Nadir (TL2CO2LN)

    Atmospheric Science Data Center

    2015-05-08

    TES/Aura L2 Carbon Dioxide (CO2) Lite Nadir (TL2CO2LN) News:  TES ... Level:  L2 Instrument:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 km nadir ... OPeNDAP Access:  OPeNDAP Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  5. TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORN)

    Atmospheric Science Data Center

    2015-02-04

    TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORN) News:  TES News Join ... L2 Platform:  TES/Aura L2 Formic Acid Spatial Coverage:  5.3 x 8.5 km nadir Spatial ... Access:  OPeNDAP Parameters:  Formic Acid Volume Mixing Ratio Precision Vertical Resolution Order ...

  6. TES/Aura L2 Formic Acid (FOR) Lite Nadir (TL2FORLN)

    Atmospheric Science Data Center

    2015-06-16

    TES/Aura L2 Formic Acid (FOR) Lite Nadir (TL2FORLN) News:  TES News ... L2 Instrument:  TES/Aura L2 Formic Acid Spatial Coverage:  5.3 km nadir Spatial ... Access:  OPeNDAP Parameters:  Formic Acid Volume Mixing Ratio Vertical Resolution Precision Order ...

  7. TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORNS)

    Atmospheric Science Data Center

    2015-02-04

    TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORNS) News:  TES News Join ... L2 Platform:  TES/Aura L2 Formic Acid Spatial Coverage:  5.3 x 8.5 km nadir Spatial ... Access:  OPeNDAP Parameters:  Formic Acid Volume Mixing Ratio Precision Vertical Resolution Order ...

  8. TES/Aura L2 Ammonia (NH3) Lite Nadir (TL2NH3LN)

    Atmospheric Science Data Center

    2015-06-16

    TES/Aura L2 Ammonia (NH3) Lite Nadir (TL2NH3LN) News:  TES News ... Level:  L2 Instrument:  TES/Aura L2 Ammonia Spatial Coverage:  5.3 km nadir Spatial ... OPeNDAP Access:  OPeNDAP Parameters:  Ammonia Order Data:  Reverb:   Order Data ...

  9. Effects of Nadir CD4 Count and Duration of HIV Infection on Brain Volumes in the HAART Era

    PubMed Central

    Cohen, Ronald A.; Harezlak, Jaroslaw; Schifitto, Giovanni; Hana, George; Clark, Uraina; Gongvatana, Assawin; Paul, Robert; Taylor, Michael; Thompson, Paul; Algers, Jeffery; Brown, Mark; Zhong, Jianhui; Campbell, Thomas; Singer, Elyse; McMahon, Deborah; Tso, Yuen; Yiannoutsos, Constantin T; Navia, Bradford

    2010-01-01

    Background Cerebral atrophy is a well described, but poorly understood complication of HIV infection. Despite reduced prevalence of HIV-associated dementia in the HAART era, HIV continues to affect the brains of patients with chronic infection. In this study we examine patterns of brain volume loss in HIV infected patients on HAART, and demographic and clinical factors contributing to it. We hypothesized that nadir CD4+ lymphocyte count, duration of HIV infection and age would be associated with reduced cortical volumes. Methods Volumes of cortical and subcortical regions in 69 HIV-infected neuroasymptomatic (NA) individuals and 13 with at least mild AIDS dementia complex (ADC) were measured using voxel-based morphometry. Demographic and clinical factors (age, plasma HIV RNA level, current and nadir CD4 count, duration of infection, CNS penetration of antiretroviral regimen) along with their interactions were entered into a regression model selection algorithm to determine the final models that best described regional brain volumes. Results Relative to NA, individuals with ADC exhibited decreased total gray matter and parietal cortex volumes and increased total ventricular volumes. Final regression models showed overall cerebral volume, including gray and white matter volume and volumes of the parietal, temporal, and frontal lobes and the hippocampus, were most strongly associated with disease history factors (nadir CD4 and duration of infection). In contrast, basal ganglia volumes were related most strongly to current disease factors, most notably plasma HIV RNA. Conclusions These findings indicate that individuals with a history of chronic HIV infection with previous episodes of severely impaired immune function, as reflected by reduced nadir CD4 + lymphocyte count, may be at greatest risk for cerebral atrophy. The pattern of HIV-associated brain loss may be changing from a subcortical to a cortical disease among patients who are largely asymptomatic on HAART. PMID:20113183

  10. Looking Beyond the Lamppost: Finding Keys to Discovery in Off-Nadir and Multiangle Remote Sensing

    NASA Astrophysics Data System (ADS)

    Diner, D. J.; Davies, R.; Kahn, R. A.; Martonchik, J. V.; Garay, M. J.; di Girolamo, L.

    2005-12-01

    For many years, single-angle observations of clouds and aerosols have been the mainstays of satellite remote sensing, with "off-nadir effects" typically considered sources of bias or error. Yet as with the individual who searches under a lamppost for lost keys because the light is better, this familiar view does not factor in the benefits of casting the observational net more broadly. For many applications, the intrinsic power of multispectral observations is magnified when expanded to a multiangle perspective. Further, data from sensors having routine global coverage and ever-improving resolution (e.g., POLDER, ATSR, MISR) have demonstrated the ability to turn panoramic, multiangle vision from a source of confusion to a wellspring of structural and morphological information that cannot be gleaned from, or requires fewer underlying assumptions than, single-angle approaches. We identify new pathways to atmospheric discovery using illustrations from the 9-angle MISR experiment on Terra. Retrievable quantities with benefits to climate, weather, and environmental studies include aerosol properties over challenging surfaces (including bright deserts and Case 2 waters) using bidirectional reflectance to decouple surface and atmospheric effects; aerosol microphysical properties such as particle shape by sampling the scattering phase function; cloud-top heights derived geometrically, independent of radiometric calibration, temperature profiles, or cloud emissivities; cloud-track wind estimates from feature identification across multiple views; 3-D cloud morphologies constructed by looking down cloud sides; and distinctions between polar clouds and surface ice based on their angular scattering. Directional radiation measurements also provide independent checks on model assumptions conventionally used in satellite retrievals, such as the use of 1-D radiative transfer (RT) theory, and demonstrate the importance of developing more sophisticated, 3-D approaches. We will incorporate examples of capabilities that were unanticipated or conceptual before launch, and discuss the importance of multiangular perspectives in characterizing environments containing both aerosols and clouds. A discussion of future multiangle sensor evolution, and the importance of advances in RT modeling, will be included.

  11. [Treatment of chronic primary open-angle glaucoma. Long-term functional results].

    PubMed

    Demailly, P; Gruber, D; Kretz, G

    1989-01-01

    The functional results of the treatment of primary open angle glaucoma (POAG) were analysed. A retrospective study was undertaken on 437 eyes from 282 patients (137 women, 145 men) followed in Saint Joseph's Hospital (Paris). The mean follow-up was 9.7 years (4-22 years). 265 eyes received only medical treatment, 83 eyes argon laser trabeculoplasty (ALT) and 89 eyes surgery (66 trabeculectomies - 23 cataract-glaucoma combined operations). At least twice a year, intraocular pressure (IOP), visual acuity (VA) and mean total visual capability (TVC) on the Friedmann analyser were recorded on a computer. The severity gradient (SG) was calculated from the evolution gradient of TVC versus IOP with time for each group (medical, ALT, surgery) before and after treatment. Medical SG was not significantly different from ALT SG or surgery SG (trabeculectomy or combined surgery). For each group, SG before treatment was not significantly different from SG after treatment. For tonometric failures after ALT or surgery, SG before treatment was not different from SG after treatment. Nevertheless, after trabeculectomy, in the cases of clear tonometric success (IOP less than or equal to 16 mmHg), SG was significantly improved (p less than 0.001). On the other hand, no positive influence was noted on visual field evolution in cases of a commonly admitted good tonometric control (IOP less than or equal to 21 mmHg). Visual acuity loss after trabeculectomy was greatest during the first year (6/20). The cataractogenic role of trabeculectomy was statistically confirmed. The incidence of cataract at 5 years was 46%. This cataractogenic effect occurred significantly more after 55 years. We discuss tonometric effect on TVC evolution.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2699612

  12. MODIS-N - Moderate Resolution Imaging Spectrometer-Nadir

    NASA Technical Reports Server (NTRS)

    Weber, Richard R.; Thompson, Leslie L.

    1990-01-01

    The Moderate Resolution Imaging Spectrometer-Nadir (MODIS-N) for the Earth Observing System (EOS) is intended to provide daily global surveys for the atmosphere, the oceans, and the land. To achieve this capability, MODIS-N requires an at-least 2300-km swath width, and provides geometric-instantaneous-fields-of-view (GIFOVs) that are either 856 m, 428 m, or 214 m in size with reference to a 705 km satellite altitude. The 214 m GIFOV may or may not be used depending on total data rate impact assessments traded with science needs. To achieve the data for the multiplicity of science investigations MODIS-N provides nominally 36 spectral bands that are selected for specific locations and bandpasses in the spectral range from the visible to the long wave infrared. Another driver of this instrument combination is the need for long term spectral and radiometric calibration stability. Specific calibration capabilities are to be built into MODIS-N to achieve calibration knowledge over a 5 year operational life.

  13. Crown depth as a result of evolutionary games: decreasing solar angle should lead to shallower, not deeper crowns.

    PubMed

    Vermeulen, Peter Johannes

    2014-06-01

    There is a general notion in the literature that, with increasing latitude, trees have deeper crowns as a result of a lower solar elevation angle. However, these predictions are based on models that did not include the effects of competition for light between individuals. Here, I argue that there should be selection for trees to increase the height of the crown base, as this decreases shading by neighbouring trees, leading to an evolutionarily stable strategy (ESS). Because the level of between-tree shading increases with decreasing solar angle, the predicted ESS will shift to higher crown base height. This argument is supported by a simulation model to check for the effects of crown shape and the change of light intensity that occurs with changing solar angle on model outcomes. So, the lower solar angle at higher latitudes would tend to select for shallower, and not deeper, crowns. This casts doubt on the common belief that a decreasing solar angle increases crown depth. More importantly, it shows that different assumptions about what should be optimized can lead to different predictions, not just for absolute trait values, but for the direction of selection itself. PMID:24548219

  14. Experimental result and discussions on applications for a variable phase angle 3-cylinder Stirling heat pump

    SciTech Connect

    Ohtomo, M.; Isshiki, N.

    1998-07-01

    Experimental studies on a 3-temperature, 3-cylinder Stirling cycle machine with variable phase angles of the hot cylinder have been done using 4 MPa helium. The work and heat output of each cylinder, measured by P-V diagrams, were very close to the expected values by the original vector analysis for multi-cylinder variable phase angle Stirling cycle machines, reported earlier by the authors. Studies on future applications of this machine were carried out, and are discussed. One is seasonal supply of heat and cold, the others are the first and second kinds of heat pumps. This kind of machine will have many applications in supplying hot or cold heat flexibly to a single machine, using both heat and electric power with variable ratios.

  15. The ExoMars Trace Gas Orbiter NOMAD Spectrometer Suite for Nadir and Solar Occultation Observations of Mars' Atmosphere

    NASA Astrophysics Data System (ADS)

    Thomas, Ian; Carine Vandaele, Ann; López-Moreno, José Juan; Patel, Manish; Bellucci, Giancarlo; Drummond, Rachel; Neefs, Eduard; Depiesse, Cedric; Daerden, Frank; Rodriguez-Gómez, Julio; Neary, Lori; Robert, Séverine; Willame, Yannick; Mahieux, Arnaud

    2015-04-01

    NOMAD (Nadir and Occultation for MArs Discovery) is one of four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in January 2016 and to begin nominal science mission around Mars in late 2017. It consists of a suite of three high-resolution spectrometers - Solar Occultation (SO), LNO (Limb Nadir and Occultation) and UVIS (Ultraviolet-Visible) - which will generate a huge dataset of Martian atmospheric observations during the mission, across a wide spectral range. Specifically, the SO spectrometer channel will perform occultation measurements, operating between 2.2-4.3?m at a resolution of 0.15cm-1, with 180-1000m vertical spatial resolution and an SNR of 1500-3000. LNO will perform limb scanning, nadir and occultation measurements, operating between 2.2-3.8?m at a resolution of 0.3cm-1. In nadir, global coverage will extend between ±74O latitude with an IFOV of 0.5x17km on the surface. This channel can also make occultation measurements should the SO channel fail. UVIS will make limb, nadir and occultation measurements between 200-650nm, at a resolution of 1nm. It will have 300-1000m vertical resolution during occultation and 5x60km ground resolution during 15s nadir observations. An order-of-magnitude increase in spectral resolution over previous instruments will allow NOMAD to map previously unresolvable gas species, such as important trace gases and isotopes. CO, CO2, H2O, C2H2, C2H4, C2H6, H2CO, CH4, SO2, H2S, HCl, O3 and several isotopologues of methane and water will be detectable, providing crucial measurements of the Martian D/H and methane isotope ratios. It will also be possible to map the sources and sinks of these gases, such as regions of surface volcanism/outgassing and atmospheric production, over the course of an entire Martian year, to further constrain atmospheric dynamics and climatology. NOMAD will also continue to monitor the Martian water, carbon, ozone and dust cycles, extending existing datasets made by successive space missions in the past decades, and to derive surface UV radiation levels. Using SO and LNO in combination with UVIS, aerosol properties such as optical depth, composition and size distribution can be derived for atmospheric particles and for distinguishing dust from ice aerosols. The NOMAD science team will interpret instrument observations using simulations of the GEM-Mars global circulation model. This GCM can model complex atmospheric and chemical processes, such as heterogeneous chemistry, phase transitions, and regolith interaction on both a localised and global scale. Model results can then influence the selection of observational modes and measurement parameters, refining future observations to optimise science return. The instrument, as of January 2015, is currently being assembled and tested. By April, the instrument will have undergone a full range of tests, calibration at Centre Spatial de Liège, and will have been delivered to ESA for mounting onto the Trace Gas Orbiter.

  16. [Timolol maleate: results of its long-term action in the treatment of chronic primary open-angle glaucoma].

    PubMed

    Demailly, P; Lehner, M A; Pigot, C

    1978-12-01

    Three groups of patients with chronic open-angle glaucoma, who had ineluded in the previous study, had been treated with timolol twice daily for more than a year. The long-term results confirm the efficacity noted in the medium-term survey, and the absence of side-effects, especially those related to the pulse rate and blood pressure in some of the patients. Drug associations had been necessary:--pilocarpin,--acetazolamid, seem to have the best synergic action with timolol. PMID:155100

  17. First results from the Isaac Newton Telescope Wide Angle Survey: The z>5 quasar survey

    E-print Network

    R. G. Sharp; R. G. McMahon; M. J. Irwin; S. T. Hodgkin

    2001-09-24

    We report the first results of an observational program designed to determine the luminosity density of high redshift quasars (z > 5 quasars) using deep multi-colour CCD data. We report the discovery and spectra of 3 i 4.4) quasars, including one with z > 5. At z=5.17, this is the fourth highest redshift quasar currently published. Using these preliminary results we derive an estimate of the M \\rm_B Isaac Newton Telescope as part of the Public Isaac Newton Group Wide Field Survey (WFS). This initial sample of objects is taken from two fields of effective area $\\sim 12.5deg ^2$ from the final $\\sim 100deg ^2$.

  18. Combined Wind Vector and Sea State Impact on Ocean Nadir-Viewing Ku- and C-Band Radar Cross-Sections

    PubMed Central

    Tran, Ngan; Chapron, Bertrand

    2006-01-01

    The authors report the first results in studying the polarization anisotropy of the microwave backscatter from nadir observations provided by Jason-1 altimeter in both Ku- and C-band. A small but clear wind direction signal for wind speeds above 6 m/s is revealed. These azimuthal variations of radar cross-section increase with increasing wind speed up to 14 m/s. The signatures then level off at higher winds. These results extend, for the first time, recent theoretical improved scattering approximation, and point some similarities between scattering and emission mechanisms at nadir. The observed directional effect can thus be interpreted as a signature of the curvature anisotropy of wind-generated short-scale waves. Sensitivities to both wind speed and sea state are also reported in the present analysis.

  19. Recent Results from the Wide Angle Search for Planets (WASP) Prototype

    NASA Astrophysics Data System (ADS)

    Kane, S. R.; Horne, K.; Lister, T.; Collier Cameron, A.; Street, R. A.; Pollacco, D. L.; James, D.; Tsapras, Y.

    2004-12-01

    WASP0 is a prototype for what is intended to become a collection of WASPs whose primary aim is to detect transiting extra-solar planets across the face of their parent star. We present some recent results from the WASP0 camera, including observations of the known transiting planet around HD 209458. The current status of the next generation camera (SuperWASP) located on La Palma is briefly outlined.

  20. Comparison of biochemical failure rates between permanent prostate brachytherapy and radical retropubic prostatectomy as a function of posttherapy PSA nadir plus ‘X’

    PubMed Central

    2014-01-01

    Background Prostate-specific antigen (PSA) nadir?+?2 ng/mL, also known as the Phoenix definition, is the definition most commonly used to establish biochemical failure (BF) after external beam radiotherapy for prostate cancer management. The purpose of this study is to compare BF rates between permanent prostate brachytherapy (PPB) and radical retropubic prostatectomy (RRP) as a function of PSA nadir plus varying values of X and examine the associated implications. Methods and materials We retrospectively searched for patients who underwent PPB or RRP at our institution between 1998 and 2004. Only primary patients not receiving androgen-deprivation therapy were included in the study. Three RRP patients were matched to each PPB patient on the basis of prognostic factors. BF rates were estimated for PSA nadirs?+?different values of X. Results A total of 1,164 patients were used for analysis: 873 in the RRP group and 291 in the PPB group. Patients were equally matched by clinical stage, biopsy Gleason sum, primary Gleason grade, and pretherapy PSA value. Median follow-up was 3.1 years for RRP patients and 3.6 years in the PPB group (P =?.01). Using PSA nadir?+?0.1 ng/mL for the definition of BF, the 5-year BF rate was 16.3% for PPB patients and 13.5% for RRP patients (P =?.007), whereas at nadir?+?2 ng/mL or greater, the BF rates were less than 3% and were indistinguishable between PPB and RRP patients. Conclusions In a cohort of well-matched patients who had prostatectomy or brachytherapy, we examined BF as a function of nadir?+?X, where X was treated as a continuous variable. As X increases from 0.1 to 2.0 ng/mL, the BF curves converge, and above 2.0 ng/mL they are essentially indistinguishable. The data presented are of interest as BF definitions continue to evolve. PMID:25074478

  1. Complexities of nadir-looking radiometric temperature measurements of plant canopies

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Idso, S. B.; Pinter, P. J., Jr.; Jackson, R. D.; Reginato, R. J.

    1980-01-01

    Effective radiant temperatures (ERTs) of five wheat canopies in different stages of development were measured during morning and noon periods. The observed variability in nadir sensor response was quantitatively described as a function of canopy structure and the vertical temperature profile of canopy components. In many cases, the nadir sensor ERT was a poor measure of vegetation temperature due to effects of soil emissions. Strong vertical temperature profiles of vegetation components were also observed. The theory and measurements presented document that remote measurements of vegetation canopy temperatures cannot be made indiscriminately over large spatial regions without consideration of the underlying physical principles.

  2. Recent Results from the Wide Angle Search for Planets (WASP) Prototype

    NASA Astrophysics Data System (ADS)

    Kane, S. R.; Horne, K.; Street, R. A.; Pollaco, D. L.; James, D.; Tsapras, Y.; Collier Cameron, A.

    WASP0 is a prototype for what is intended to become a collection of WASPs whose primary aim is to detect transiting extrasolar planets across the face of their parent star. The WASP0 instrument is a wide-field (9-degree) 6.3 cm aperture F/2.8 Apogee 10 CCD camera (2Kx2K chip, 16-arcsec pixels). The camera is mounted piggy-back on a commercial 10-inch Meade telescope. We present some recent results from the WASP camera, including observations from La Palma of the known transiting planet around HD 209458 and preliminary analysis of other stars located in the same field. We also outline further problems which restrict the ability to achieve photon limited precision with a wide-field commercial CCD.

  3. Assessment of the stratospheric NO2 column using long-term ground-based UV-visible and satellite nadir observations

    NASA Astrophysics Data System (ADS)

    Pinardi, Gaia; Van Roozendael, Michel; Lambert, Jean-Christopher; Hendrick, Francois; Granville, José; Tack, Frederik; Goutail, Florence; Pommereau, Jean-Pierre; Pazmino, Andrea; Wittrock, Folkard; Richter, Andreas; Wagner, Thomas; Gu, Myojeong; Friess, Udo; Navarro, Monica; Puentedura, Olga

    2015-04-01

    Zenith-sky UV-visible instruments have been used to monitor stratospheric NO2 columns from pole to pole for more than 2 decades, as part of the Network for the Detection of Atmospheric Composition Change (NDACC). Long-term monitoring and fit-for-purpose data quality are essential commitments of the network. Recently, recommendations were made for a better harmonization of the retrieval of NO2 stratospheric vertical columns (Van Roozendael and Hendrick 2012, http://ndacc-uvvis-wg.aeronomie.be/tools/NDACC_UVVIS-WG_NO2settings_v4.pdf). Those include, in addition to the use of harmonized SCD settings, a common approach to the air-mass factor (AMF) calculation, based on pre-calculated look-up tables of climatological AMFs resolved in latitude, time, wavelength, surface albedo, solar zenith angle and station altitude. The impact of the NDACC recommendations on the quality of the zenith-sky UV-visible stratospheric NO2 columns is first illustrated based on 10 SAOZ (Système d'Analyse par Observations Zénithales) instruments deployed from the Arctic to the Antarctic. The long-term time-series of SAOZ and other ground-based NDACC zenith-sky measurements are then used in synergy with data from an ensemble of satellite UV-vis nadir sensors (GOME-2, SCIAMACHY and OMI), for characterising the stratospheric NO2 columns on the global scale. Appropriate photochemical state matching is applied whenever necessary to combine/compare the different data sets. Results are interpreted in terms of ground-based network data homogeneity, and accuracy, consistency and long-term stability of space-borne stratospheric NO2 columns. The consistency with previously published studies including stratospheric NO2 column measurements from limb sensors such as MIPAS and SCIAMACHY is also discussed. These quality-assessed ground-based and satellite data sets offer new perspectives for the analysis of the variability and trends of stratospheric NO2 at the global scale.

  4. Results from the Wide Angle Search for Planets Prototype (WASP0) III: Planet Hunting in the Draco Field

    E-print Network

    Stephen R. Kane; Andrew Collier Cameron; Keith Horne; David James; T. A. Lister; Don L. Pollacco; Rachel A. Street; Yiannis Tsapras

    2005-10-01

    The Wide Angle Search for Planets prototype (WASP0) is a wide-field instrument used to search for extra-solar planets via the transit method. Here we present the results of a monitoring program which targeted a 9-degree field in Draco. WASP0 monitored 35000 field stars for two consecutive months. Analysis of the lightcurves resulted in the detection of 11 multi-transit candidates and 3 single-transit candidates, two of which we recommend for further follow-up. Monte-Carlo simulations matching the observing parameters estimate the expected number of transit candidates from this survey. A comparison of the expected number with the number of candidates detected is used to discuss limits on planetary companions to field stars.

  5. International Database on Human Capital Quality Nadir ALTINOK and Hatidje MURSELIa*

    E-print Network

    Boyer, Edmond

    International Database on Human Capital Quality Nadir ALTINOK and Hatidje MURSELIa* a IREDU. This allowed us to build indicators of comparable data concerning the quality of human capital in numerous. Keywords: Macroeconomic Data; Education Quality; Human Capital. J.E.L. Classification: C82; I2

  6. An exact method for computing the nadir values in multiple objective linear programming

    Microsoft Academic Search

    Maria João Alves; João Paulo Costa

    2009-01-01

    In this paper we propose a new method to determine the exact nadir (minimum) criterion values over the efficient set in multiple objective linear programming (MOLP). The basic idea of the method is to determine, for each criterion, the region of the weight space associated with the efficient solutions that have a value in that criterion below the minimum already

  7. Freeze\\/thaw-induced embolism depends on nadir temperature: the heterogeneous hydration hypothesis

    Microsoft Academic Search

    J. WOLFE

    Freeze\\/thaw-induced embolism was studied in leaves of field-grown snow gum ( Eucalyptus pauciflora ) subject to frequent morning frosts. Juvenile trees were grown in bur- ied pots, brought to the laboratory at different stages of acclimation and subjected to simulated frost-freezes (at 2 ° ° ° ° C h ? ? ? ? 1 ) to nadir temperatures of ?

  8. Toward an Estimation of Nadir Objective Vector Using a Hybrid of Evolutionary and Local Search Approaches

    Microsoft Academic Search

    Kalyanmoy Deb; Kaisa Miettinen; Shamik Chaudhuri

    2010-01-01

    A nadir objective vector is constructed from the worst Pareto-optimal objective values in a multiobjective optimization problem and is an important entity to compute because of its significance in estimating the range of objective values in the Pareto-optimal front and also in executing a number of interactive multiobjective optimization techniques. Along with the ideal objective vector, it is also needed

  9. The influence of polarization on box air mass factors for UV/vis nadir satellite observations

    NASA Astrophysics Data System (ADS)

    Hilboll, Andreas; Richter, Andreas; Rozanov, Vladimir V.; Burrows, John P.

    2015-04-01

    Tropospheric abundances of pollutant trace gases like, e.g., NO2, are often derived by applying the differential optical absorption spectroscopy (DOAS) method to space-borne measurements of back-scattered and reflected solar radiation. The resulting quantity, the slant column density (SCD), subsequently has to be converted to more easily interpretable vertical column densities by means of the so-called box air mass factor (BAMF). The BAMF describes the ratio of SCD and VCD within one atmospheric layer and is calculated by a radiative transfer model. Current operational and scientific data products of satellite-derived trace gas VCDs do not include the effect of polarization in their radiative transfer models. However, the various scattering processes in the atmosphere do lead to a distinctive polarization pattern of the observed Earthshine spectra. This study investigates the influence of these polarization patterns on box air mass factors for satellite nadir DOAS measurements of NO2 in the UV/vis wavelength region. NO2 BAMFs have been simulated for a multitude of viewing geometries, surface albedos, and surface altitudes, using the radiative transfer model SCIATRAN. The results show a potentially large influence of polarization on the BAMF, which can reach 10% and more close to the surface. A simple correction for this effect seems not to be feasible, as it strongly depends on the specific measurement scenario and can lead to both high and low biases of the resulting NO2 VCD. We therefore conclude that all data products of NO2 VCDs derived from space-borne DOAS measurements should include polarization effects in their radiative transfer model calculations, or at least include the errors introduced by using linear models in their uncertainty estimates.

  10. [Trabeculectomy and trabeculo-retraction in the treatment of chronic primary open-angle glaucoma. Long-term tonometric results].

    PubMed

    Demailly, P; Kretz, G; Gruber, D

    1989-01-01

    The long term tonometric results of laser (Argon Laser Trabeculoplasty) and surgical (Trabeculectomy and combined-surgery) treatment in Primitive Chronic Open Angle Glaucoma are analysed on 184 eyes by a retrospective study. Three groups of patients are compared: group I: 81 trabeculoplasties followed 4 years, group II: 75 trabeculectomies followed 5 years, group III: 28 combined-surgery (intra-capsular cataract extraction without implantation combined with a trabeculectomy) followed 5 years. For the three groups, reduce of IOP is noted after 6 months but seems less important after 30 months. Instantaneous results curves show a success rate of 80 to 100% (of which 10 to 20% with additional medical treatment). But cumulative failures rates are higher: more than 50% at 4 years for group I and group II, and only 29% at 5 years for group III. These results are confirmed by actuarial curves: group I: probability success rate of 65% at 4 years group II: probability success rate of 49% at 5 years group III: probability success rate of 73% at 5 years. The comparison of group I and II by actuarial curves is not statistically significant (Logrank test: chi 2 = 0.05). We had discussed the advantage of a new prospective randomised study. PMID:2635197

  11. View angle dependence of MODIS liquid water path retrievals in warm oceanic clouds

    PubMed Central

    Horváth, Ákos; Seethala, Chellappan; Deneke, Hartwig

    2014-01-01

    We investigated the view angle dependence of domain mean Moderate Resolution Imaging Spectroradiometer (MODIS) liquid water path (LWP) and that of corresponding cloud optical thickness, effective radius, and liquid cloud fraction as proxy for plane-parallel retrieval biases. Independent Advanced Microwave Scanning Radiometer–EOS LWP was used to corroborate that the observed variations with sun-view geometry were not severely affected by seasonal/latitudinal changes in cloud properties. Microwave retrievals showed generally small (<10%) cross-swath variations. The view angle (cross-swath) dependence of MODIS optical thickness was weaker in backscatter than forward scatter directions and transitioned from mild ? shape to stronger ? shape as heterogeneity, sun angle, or latitude increased. The 2.2 µm effective radius variations always had a ? shape, which became pronounced and asymmetric toward forward scatter in the most heterogeneous clouds and/or at the lowest sun. Cloud fraction had the strongest and always ?-shaped view angle dependence. As a result, in-cloud MODIS cloud liquid water path (CLWP) showed surprisingly good view angle (cross-swath) consistency, usually comparable to that of microwave retrievals, due to cancelation between optical thickness and effective radius biases. Larger (20–40%) nadir-relative increases were observed in the most extreme heterogeneity and sun angle bins, that is, typically in the polar regions, which, however, constituted only 3–8% of retrievals. The good consistency of MODIS in-cloud CLWP was lost for gridbox mean LWP, which was dominated by the strong cloud fraction increase with view angle. More worryingly, MODIS LWP exhibited significant and systematic absolute increases with heterogeneity and sun angle that is not present in microwave LWP. Key Points Microwave LWP shows small overall and cross-swath variations MODIS in-cloud LWP also shows good view angle consistency in most cases MODIS retrievals show strong overall increase with heterogeneity and sun angle PMID:25821665

  12. Lightning-illuminated cloud top surface from nadir observations on-board the International Space Station

    NASA Astrophysics Data System (ADS)

    Farges, T.; Blanc, E.

    2012-12-01

    The Lightning and Sprites Observation (LSO) experiment has been designed to test a sprite and lightning differentiation method in the case of nadir observation. LSO was composed of two cameras. The first one was equipped of a narrowband filter around 763 nm to maximize the contrast between sprites and lightning. The second one is exactly the same but without filter. LSO was operated during 31 days giving 19 hours cumulative time of observations spreading over 2001 to 2004 and 210 lightning flashes. The main interest of this experiment regarding other recent space-borne experiments dedicated to the lightning flash studies was its spatial resolution, 400 m, and its field of view (207 km x 207 km at ground). Each lightning flash can then be completely observed with fine structure details. The whole dataset is available as images in auxiliary material. Using the whole dataset, statistics about the peak and mean radiance and the lightning-illuminated cloud top surface are realized and discussed. The main results are: (i) the surface of the lightning-illuminated cloud top increases not linearly with the peak radiance and (ii) the lighting flash radiance is decreasing radially but its shape cannot be exactly represented by a two-dimensional Gaussian which overestimates the mean radiance. These data should be useful for the preparation of future space missions dedicated to lightning or TLEs observations. These observations will be complemented by new ones from the NASA Crew Earth Observation program. They provide lightning flash pictures over Oklahoma with an unprecedented spatial resolution from space (~40 m) inside a large field of view of about 150 km x 100 km.

  13. Retrieval of atmospheric CO2 from satellite near-infrared nadir spectra: inter-comparison of different algorithms

    NASA Astrophysics Data System (ADS)

    Reuter, M.; Buchwitz, M.; Schneising, O.; Heymann, J.; Bovensmann, H.; Burrows, J. P.

    2012-04-01

    Carbon dioxide is the most important anthropogenic greenhouse gas. Its global increasing concentration in the Earth's atmosphere is the main driver for global warming. However, in spite of its importance, there are still large uncertainties on its global sources and sinks. Satellite measurements, if accurate and precise enough, have the potential to reduce these surface flux uncertainties. At present, there are only two satellite instruments orbiting the Earth which are able to measure the CO2 mixing ratio (XCO2) with large sensitivity also in the boundary layer. These are SCIAMACHY (launched in 2002) and GOSAT (launched in 2009). Worldwide, several teams of scientists are developing algorithms aiming to meet the challenging user requirements. The majority of these groups take part in ESA's climate change initiative (CCI) on greenhouse gases (GHG) where there algorithms stand into competition. Within the presentation, recent inter-comparison results will be shown focusing on global SCIAMACHY nadir observations.

  14. [Results 1 year after trabeculoretraction by 360 degree argon laser in the treatment of open-angle glaucoma].

    PubMed

    Demailly, P; Valtot, F; Kopel, J; Ecoffet, M

    1985-01-01

    On 210 glaucomatous patients (119 men, 91 women), 390 eyes with open angle chronic glaucoma, we have performed an argon laser trabeculoplasty according to Wise technique (360 degrees in one time). ALT was presented as an alternative to surgery. Therefore results were appreciated so that ALT allowed or not to avoid surgery. After one year, the rate of failures was: on all the 390 eyes: 15 p. cent on O.A.C.G. simplex: 6.7 p. cent on myopic glaucoma: 7 p. cent on pigmentary glaucoma: 29.5 p. cent on capsular glaucoma: 6 p. cent after trabeculectomy: 62 p. cent on aphakic glaucoma: 50 p. cent on secondary glaucoma: 33 p. cent on combined glaucoma: 0 p. cent In the group of successful results, ALT allowed to lower medical treatment in at less 70 p. cent after one year of follow-up except for pigmentary glaucoma where, in almost all cases, medication before ALT had to be continued. PMID:3998404

  15. Results and Lessons Learned From the KELT-North Wide-angle Transit Survey of Bright Stars

    NASA Astrophysics Data System (ADS)

    Beatty, Thomas G.

    2014-01-01

    Since 2006, the KELT-North transit survey has been collecting wide-angle precision photometry for 20% of the sky. This gave us the unique opportunity to conduct a statistically controlled and rigorous search for transiting planets among the 220,000 dwarfs stars targeted by the survey over 6 years. To date, we have detected over 18 transiting hot Jupiters, several of which have been new discoveries. Based on my previous work on theoretical transit survey statistics and yields, we consciously designed the lightcurve reduction and candidate selection process to be statistically robust and effective. I will discuss the process behind our candidate selection process, the lessons learned from operating the survey, highlights from KELT’s first detections, and some initial results from the exoplanet statistics determined by the survey. Many of the considerations that went into KELT’s operations will be directly relevant to the upcoming TESS survey mission, which will be searching the same stellar population with the same field of view for transiting planets.

  16. Structure of star-burst dendrimers: A comparison between small angle x-ray scattering and computer simulation results

    SciTech Connect

    Rathgeber, Silke [Forschungszentrum Julich, Julich, Germany; Pakula, Tadeusz [Max-Planck-Institute for Polymer Research; Urban, Volker S [ORNL

    2004-08-01

    We investigated the generation dependent shape and internal structure of star-burst dendrimers under good solvent conditions using small angle x-ray scattering and molecular modeling. Measurements have been performed on poly(amidoamine) dendrimers with generations ranging from g = 0 up to g = 8 at low concentrations in methanol. We described the static form factor P(q) by a model taking into account the compact, globular shape as well as the loose, polymeric character of dendrimers. Monomer distributions within dendrimers are of special interest for potential applications and have been characterized by the pair correlation function {gamma}(r), as well as by the monomer and end-group density profile, {rho}(r) and {rho}{sub e}(r), respectively. Monomer density profiles and {gamma}(r) can be derived from P(q) by modeling and via a model independent approach using the inverse Fourier transformation algorithm first introduced by Glatter. Experimental results are compared with computer simulations performed for single dendrimers of various generations using the cooperative motion algorithm. The simulation gives direct access to {gamma}(r) and {rho}(r), allows an independent determination of P(q), and yields in addition to the scattering experiment information about the distribution of the end groups. Excellent qualitative agreement between experiment and simulation has been found.

  17. S-NPP OMPS Nadir In-Flight Performance

    NASA Astrophysics Data System (ADS)

    Pan, S.; Flynn, L. E.; Niu, J.; Grotenhuis, M.; Beck, C. T.; Beach, E.; Zhang, Z.; Tolea, A.

    2014-12-01

    This presentation describes the results of in-flight characterization of the S-NPP Ozone Mapping Profiler Suite (OMPS) charge-coupled device (CCD) performance during the first nearly three years of the OMPS mission in orbit. Data from OMPS's three two-dimension CCD arrays have been collected to characterize in-flight detector behaviors. Our results show that offset, gain, and dark current rate trends remain within sensor requirement limits. System linearity performance trends are stable. The distribution of individual pixel dark rates is slowly growing as expected from pre-launch analyses. The current in-flight dark and linearity calibration corrections provide Sensor Data Records (SDRs) with insignificant error after correction of less than an average of ~0.1% in the Earth radiance retrieval. The instrument optics is less stable than predicted leading to intra-orbit wavelength scale variations as the temperature gradients vary across the instrument. Measurement-based estimates of these effects are as large a ±0.02 nm and are used to make corrections to within +-0.005 nm on a granule by granule basis. Examination of reflectivity, aerosol and ozone EDRs provide evidence of absolute calibration errors with a significant cross track variation. A soft calibration adjustment is under development to remove them.

  18. Note on the effect of horizontal gradients for nadir-viewing microwave and infrared sounders

    Microsoft Academic Search

    J. Joiner; P. Poli

    2005-01-01

    SUMMARY Passive microwave and infrared nadir sounders such as the Advanced Microwave Sounding Unit-A (AMSU- A) and the Atmospheric InfraRed Sounder (AIRS), both flying on NASA's EOS polar-orbiting Aqua satellite, provide information about vertical temperature and humidity structure that is used in data assimilation systems for numerical weather prediction and climate applications. These instruments scan across track so that, at

  19. Retrieval of atmospheric CO2 from SCIAMACHY nadir spectra

    NASA Astrophysics Data System (ADS)

    Reuter, Maximilian; Buchwitz, Michael; Schneising, Oliver; Heymann, Jens; Bovensmann, Heinrich; Burrows, John P.

    2010-05-01

    Carbon dioxide is the most important anthropogenic greenhouse gas. Its global increasing concentration in the Earth's atmosphere is the main driver for global warming. For this reason, carbon dioxide became one of the EU FP7 project Monitoring Atmospheric Composition and Climate (MACC) products. However, in spite of its importance, there are still large uncertainties on its global sources and sinks. Satellite measurements have the potential to reduce these uncertainties. At present, there are only two satellite instruments orbiting the Earth which are able to measure the CO2 mixing ratio (XCO2) with large sensitivity also in the boundary layer. In 2002 SCIAMACHY aboard ENVISAT started the time series of XCO2 observation from space followed by GOSAT which was launched in 2009. Recent results of the WFM-DOAS retrieval scheme will be shown, covering world wide data from 2003 to 2009. In this context, the strength but also weaknesses of the existing retrieval algorithm will be discussed. Maybe the most important source of potential errors are undetected sub visible cirrus clouds. A new optimal estimation based retrieval scheme will be presented which has the potential to drastically reduce these errors.

  20. In-flight flow visualization results from the X-29A aircraft at high angles of attack

    NASA Technical Reports Server (NTRS)

    Delfrate, John H.; Saltzman, John A.

    1992-01-01

    Flow visualization techniques were used on the X-29A aircraft at high angles of attack to study the vortical flow off the forebody and the surface flow on the wing and tail. The forebody vortex system was studied because asymmetries in the vortex system were suspected of inducing uncommanded yawing moments at zero sideslip. Smoke enabled visualization of the vortex system and correlation of its orientation with flight yawing moment data. Good agreement was found between vortex system asymmetries and the occurrence of yawing moments. Surface flow on the forward-swept wing of the X-29A was studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread outboard encompassing the full wing by 30 deg angle of attack. In general, the progression of the separated flow correlated well with subscale model lift data. Surface flow on the vertical tail was also studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread upward. The area of separated flow on the vertical tail at angles of attack greater than 20 deg correlated well with the marked decrease in aircraft directional stability.

  1. Equivalent Biochemical Control and Improved Prostate-Specific Antigen Nadir After Permanent Prostate Seed Implant Brachytherapy Versus High-Dose Three-Dimensional Conformal Radiotherapy and High-Dose Conformal Proton Beam Radiotherapy Boost

    SciTech Connect

    Jabbari, Siavash [Department of Radiation Oncology, University of California San Francisco, School of Medicine, San Francisco, CA (United States); Weinberg, Vivian K. [Department of Urology, University of California San Francisco, School of Medicine, San Francisco, CA (United States); Shinohara, Katsuto [Department of Biostatistics Core, University of California San Francisco, School of Medicine, San Francisco, CA (United States); Speight, Joycelyn L. [Department of Radiation Oncology, University of California San Francisco, School of Medicine, San Francisco, CA (United States); Department of Biostatistics Core, University of California San Francisco, School of Medicine, San Francisco, CA (United States); Gottschalk, Alexander R.; Hsu, I.-C.; Pickett, Barby [Department of Radiation Oncology, University of California San Francisco, School of Medicine, San Francisco, CA (United States); McLaughlin, Patrick W.; Sandler, Howard M. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI (United States); Roach, Mack, E-mail: mroach@radonc.ucsf.ed [Department of Radiation Oncology, University of California San Francisco, School of Medicine, San Francisco, CA (United States); Department of Urology, University of California San Francisco, School of Medicine, San Francisco, CA (United States)

    2010-01-15

    Purpose: Permanent prostate implant brachytherapy (PPI), three-dimensional conformal radiotherapy (3D-CRT), and conformal proton beam radiotherapy (CPBRT) are used in the treatment of localized prostate cancer, although no head-to-head trials have compared these modalities. We studied the biochemical control (biochemical no evidence of disease [bNED]) and prostate-specific antigen (PSA) nadir achieved with contemporary PPI, and evaluated it against 3D-CRT and CPBRT. Patients and Methods: A total of 249 patients were treated with PPI at the University of California, San Francisco, and the outcomes were compared with those from a 3D-CRT cohort and the published results of a high-dose CPBRT boost (CPBRTB) trial. For each comparison, subsets of the PPI cohort were selected with patient and disease criteria similar to those of the reference group. Results: With a median follow-up of 5.3 years, the bNED rate at 5 and 7 years achieved with PPI was 92% and 86%, respectively, using the American Society for Therapeutic Radiology and Oncology (ASTRO) definition, and 93% using the PSA nadir plus 2 ng/mL definition. Using the ASTRO definition, a 5-year bNED rate of 78% was achieved for the 3D-CRT patients compared with 94% for a comparable PPI subset and 93% vs. 92%, respectively, using the PSA nadir plus 2 ng/mL definition. The median PSA nadir for patients treated with PPI and 3D-CRT was 0.10 and 0.40 ng/mL, respectively (p < .0001). For the CPBRT comparison, the 5-year bNED rate after a CPBRTB was 91% using the ASTRO definition vs. 93% for a similar group of PPI patients. A greater proportion of PPI patients achieved a lower PSA nadir compared with those achieved in the CPBRTB trial (PSA nadir <=0.5 ng/mL, 91% vs. 59%, respectively). Conclusion: We have demonstrated excellent outcomes in low- to intermediate-risk patients treated with PPI, suggesting at least equivalent 5-year bNED rates and a greater proportion of men achieving lower PSA nadirs compared with 3D-CRT or CPBRTB.

  2. Increase in the maximum lift of an airplane wing due to a sudden increase in its effective angle of attack resulting from a gust

    NASA Technical Reports Server (NTRS)

    Kramer, Max

    1932-01-01

    Wind-tunnel tests are described, in which the angle of attack of a wing model was suddenly increased (producing the effect of a vertical gust) and the resulting forces were measured. It was found that the maximum lift coefficient increases in proportion to the rate of increase in the angle of attack. This fact is important for the determination of the gust stresses of airplanes with low wing loading. The results of the calculation of the corrective factor are given for a high-performance glider and a light sport plane of conventional type.

  3. Moho signature from wide-angle reflections: preliminary results of the 1993 Trans-Hudson Orogen refraction experiment

    Microsoft Academic Search

    B. Nemeth; Z. Hajnal; S. B. Lucas

    1996-01-01

    In 1993 a combined crustal seismic refraction and wide-angle reflection experiment was conducted over the northern Saskatchewan and Manitoba portion of the Trans-Hudson Orogen by LITHOPROBE. The program included three seismic lines extending over 1900 km in length. The exceptionally high-quality data collected during the field experiment included seismic reflections and refraction events from the Moho and upper lithospheric mantle.

  4. Preliminary results from a subsonic high angle-of-attack flush airdata sensing (HI-FADS) system: Design, calibration, and flight test evaluation

    NASA Technical Reports Server (NTRS)

    Whitmore, Stephen A.; Moes, Timothy R.; Larson, Terry J.

    1990-01-01

    A nonintrusive high angle-of-attack flush airdata sensing (HI-FADS) system was installed and flight-tested on the F-18 high alpha research flight vehicle. The system is a matrix of 25 pressure orifices in concentric circles on the nose of the vehicle. The orifices determine angles of attack and sideslip, Mach number, and pressure altitude. Pressure was transmitted from the orifices to an electronically scanned pressure module by lines of pneumatic tubing. The HI-FADS system was calibrated and demonstrated using dutch roll flight maneuvers covering large Mach, angle-of-attack, and sideslip ranges. Reference airdata for system calibration were generated by a minimum variance estimation technique blending measurements from two wingtip airdata booms with inertial velocities, aircraft angular rates and attitudes, precision radar tracking, and meteorological analyses. The pressure orifice calibration was based on identifying empirical adjustments to modified Newtonian flow on a hemisphere. Calibration results are presented. Flight test results used all 25 orifices or used a subset of 9 orifices. Under moderate maneuvering conditions, the HI-FADS system gave excellent results over the entire subsonic Mach number range up to 55 deg angle of attack. The internal pneumatic frequency response of the system is accurate to beyond 10 Hz. Aerodynamic lags in the aircraft flow field caused some performance degradation during heavy maneuvering.

  5. Characterisation of a stratospheric sulfate plume from the Nabro volcano using a combination of passive satellite measurements in nadir and limb geometry

    NASA Astrophysics Data System (ADS)

    Penning de Vries, M. J. M.; Dörner, S.; Pu???te, J.; Hörmann, C.; Fromm, M. D.; Wagner, T.

    2014-08-01

    The eruption of the Nabro volcano (Eritrea), which started on 12 June 2011, caused the introduction of large quantities of SO2 into the lower stratosphere. The subsequently formed sulfate aerosols could be detected for several months following the eruption. It is generally assumed that the formation of sulfate aerosols in the stratosphere is a relatively slow process, but in plumes from explosive eruptions significant amounts of aerosols have been seen to form within a few hours. We show that sulfate aerosols were present in the lower stratosphere within hours of the onset of the eruption of Nabro. Evidence comes from nadir UV Aerosol Index (UVAI) and SO2 measurements by SCIAMACHY, GOME-2 and OMI, and limb aerosol measurements by SCIAMACHY. The sulfate plume displays negative UVAI in the western part of OMI's swath and positive UVAI in the eastern part - an effect that is due to the strong viewing angle dependence of UVAI and can only be caused by a high-altitude (>11 km), non-absorbing (single-scattering albedo >0.97) aerosol plume. For the retrieval of the aerosol profile from limb measurements, the horizontal dimensions and the position of the aerosol plume need to be taken into account, otherwise both extinction and layer height may be underestimated appreciably. By combining nadir SO2 column density and UVAI with limb aerosol profiles, a stratospheric plume from Nabro could be tracked from 13 to 17 June, before the plumes from later, lower-altitude explosions started interfering with the signal. Our findings are in agreement with ground-based lidar and sun-photometer data from an MPLNET/AERONET station in Israel and with data from the satellite-borne CALIOP lidar.

  6. Characterisation of a stratospheric sulphate plume from the Nabro volcano using a combination of passive satellite measurements in nadir and limb geometry

    NASA Astrophysics Data System (ADS)

    Penning de Vries, M. J. M.; Dörner, S.; Pu??te, J.; Hörmann, C.; Fromm, M. D.; Wagner, T.

    2014-03-01

    The eruption of the Nabro volcano (Eritrea), which started on 12 June 2011, caused the introduction of large quantities of SO2 into the lower stratosphere. The subsequently formed sulphate aerosols could be detected for several months following the eruption. It is generally assumed that the formation of sulphate aerosols in the stratosphere takes about a month, but in plumes from explosive eruptions significant amounts of aerosols have been seen to form within a few hours. We show that sulphate aerosols were present in the lower stratosphere within hours of the onset of the eruption of Nabro. Evidence comes from nadir UV Aerosol Index (UVAI) and SO2 measurements by SCIAMACHY, GOME-2 and OMI, and limb aerosol measurements by SCIAMACHY. The sulphate plume displays negative UVAI in the western part of OMI's swath and positive UVAI in the eastern part - an effect that is due to the strong viewing angle dependence of UVAI and can only be caused by a high-altitude (>11 km), non-absorbing (single-scattering albedo >0.97) aerosol plume. For the retrieval of the aerosol profile from limb measurements, the horizontal dimensions and the position of the aerosol plume need to be taken into account, otherwise both extinction and layer height may be underestimated appreciably. By combining nadir SO2 column density and UVAI with limb aerosol profiles, a stratospheric plume from Nabro could be tracked from 13 to 17 June, before the plumes from later, lower-altitude explosions started interfering with the signal. Our findings are in agreement with ground-based lidar and sun-photometer data from an MPLNET/AERONET station in Israel and with data from the satellite-borne CALIOP lidar.

  7. Angle Hunting

    NSDL National Science Digital Library

    Exploratorium

    2010-01-01

    In this activity, learners use a hand-made protractor to measure angles they find in playground equipment. Learners will observe that angle measurements do not change with distance, because they are distance invariant, or constant. Note: The "Pocket Protractor" activity should be done ahead as a separate activity (see related resource), but a standard protractor can be used as a substitute.

  8. The multi-angle view of MISR detects oil slicks under sun glitter conditions

    Microsoft Academic Search

    Guillem Chust; Yolanda Sagarminaga

    2007-01-01

    We tested the use of the Multi-angle Imaging SpectroRadiometer (MISR) for detecting oil spills in the Lake Maracaibo, Venezuela, that were caused by a series of accidents between December 2002 and March 2003. The MISR sensor, onboard the Terra satellite, utilises nine cameras pointed at fixed angles, ranging from nadir to ±70.5°. Based upon the Bidirectional Reflectance Factor, a contrast

  9. Current Status of Cloud Masks for the Multi-angle Imaging SpectroRadiometer

    Microsoft Academic Search

    M. J. Wilson; G. Zhao; Y. Yang; B. Chapman; L. di Girolamo

    2004-01-01

    The Multi-angle Imaging SpectroRadiometer (MISR) on-board EOS-Terra makes observations at 9 angles (1 nadir, 8 oblique) in the visible and near-infrared. Cloud detection is a critical part of the MISR mission, but is made more complicated by the fact that there are no spectral channels longward of 866 nm in wavelength. This has led to the development of several novel

  10. Combined limb/nadir retrievals of atmospheric parameters from Mars Climate Sounder measurements

    NASA Astrophysics Data System (ADS)

    Kleinboehl, Armin; Schofield, John; Kass, David; Abdou, Wedad; Shirley, James; McCleese, Daniel

    For almost two Mars years the Mars Climate Sounder (MCS) on board the Mars Reconnaissance Orbiter has been taking measurements of the Martian surface and atmosphere. MCS is a ther-mal emission radiometer with 8 channels in the mid-and far-infrared. From its measurements, vertical profiles of atmospheric temperature, dust and water ice opacity are retrieved with a vertical resolution of 5 km on an operational basis. Measurements are performed in limb and nadir geometry early in the misssion, later in the mission the nadir measurements were replaced by on-planet measurements 8-10 degrees below the limb. Here we present an upgraded version of the MCS retrieval algorithm, which allows a combined retrieval from limb-and on-planet measurements to obtain surface temperatures and near-surface atmospheric temperatures. This extends the MCS temperature profiles from about 80 km altitude all the way down to the sur-face. First maps of daytime and nighttime surface and near-surface atmospheric temperatures will be shown. Particularly noticable are very cold nighttime surface temperatures around Tharsis and Arabia Terra, where temperatures approach the CO2 frost point. In addition we evaluate the quality of the retrievals in the lower atmosphere. Preliminary comparisons with historic measurements from Mars Global Surveyor show good agreement.

  11. The impact of particle shape on friction angle and resulting critical shear stress: an example from a coarse-grained, steep, megatidal beach

    NASA Astrophysics Data System (ADS)

    Stark, N.; Hay, A. E.; Cheel, R.; Lake, C. B.

    2013-12-01

    The impact of particle shape on the friction angle, and the resulting critical shear stress on sediment dynamics, is still poorly understood. In areas characterized by sediments of specific shape, particularly non-rounded particles, this can lead to large departures from the expected sediment dynamics. The steep slope (1:10) of the mixed sand-gravel beach at Advocate Harbour was found stable in large-scale morphology over decades, despite a high tidal range of ten meters or more, and strong shorebreak action during storms. The Advocate sand (d < 2 mm) was found to have an elliptic, plate-like shape. Exceptionally high friction angles of the material were determined using direct shear, ranging from ? ? 41-46°, while the round to angular gravel was characterized by ? = 33°. The addition of 25% of the elliptic sand to the gravel led to an immediate increase of the friction angle to ? = 38°. Furthermore, re-organization of the particles occurred during shearing, being characterized by a short phase of settling and compaction, followed by a pronounced strong dilatory behavior and an accompanying strong increase of shear stress. Long-term shearing (24 h) using a ring shear apparatus led to destruction of the particles without re-compaction. Finally, submerged particle mobilization was simulated using a tilted tray in a tank. Despite a smooth tray surface, particle motion was not initiated until reaching tray tilt angles of 31° and more, being 7° steeper than the latest gravel motion initiation. In conclusion, geotechnical laboratory experiments quantified the important impact of the elliptic, plate-like shape of Advocate Beach sand on the friction angles of both pure sand and sand-gravel mixtures. The resulting effect on initiation of particle motion was confirmed in tilting tray experiments. This makes it a vivid example of how particle shape can contribute to the stabilization of the beachface.

  12. Evaluation of the efficacy of laser peripheral iridoplasty in reversing the darkroom provocative test result in Chinese patients with primary angle closure status post laser iridotomy

    PubMed Central

    Huang, Ping; Wu, Ling-Ling

    2015-01-01

    AIM To investigate the efficacy and safety of krypton laser peripheral iridoplasty (LPIP) for Chinese patients with primary angle closure (PAC) or primary angle-closure glaucoma (PACG) status post laser iridotomy in reversing the positive results of the dark room provocative test (DRPT). METHODS This study was prospective, noncomparative, interventional case series. Thirty-three patients (thirty-eight eyes) with PAC or PACG status post patent laser iridotomy and maintained normal intraocular pressure (IOP) but with positive DRPT results were enrolled. All the subjects were treated with krypton LPIP. DRPT was repeated after krypton LPIP. Results of DRPT were recorded. The visual acuity, IOP and gonioscopy were analyzed before and after krypton LPIP. A minimum time limit for follow-up was 6mo. RESULTS Thirty-three patients (thirty-eight eyes) were followed for 17.7±8.37mo (range 7-41mo) after LPIP. Positive results of DRPT decreased from 38 eyes to 9 eyes (23.7%) after LPIP. Peripheral anterior synechiae of angle in 34 of 38 eyes (89.5%) remained unchanged at dynamic gonioscopy throughout the follow-up period after LPIP. CONCLUSION LPIP decreased positive rates of the DRPT significantly. The mechanism may be that LPIP minimized contact between the peripheral iris and trabecular meshwork, which is a key factor for developing peripheral anterior synechiae. PMID:26086012

  13. Biodegradable 3D-Porous Collagen Matrix (Ologen) Compared with Mitomycin C for Treatment of Primary Open-Angle Glaucoma: Results at 5 Years

    PubMed Central

    Yuan, Fei; Li, Lei; Chen, Xiuping; Yan, Xiang; Wang, Liyang

    2015-01-01

    Purpose. To evaluate the effectiveness and safety of the Ologen as an aid for trabeculectomy performed for primary open-angle glaucoma compared with mitomycin C. Methods. In this prospective, randomized, parallel assignment, comparative study, 31 eyes of 21 primary open-angle glaucoma patients were allocated for trabeculectomy with the Ologen implant; another 32 eyes of 23 patients were treated with trabeculectomy augmented with mitomycin C. The patients were followed up for 5 years and evaluated for intraocular pressure, rate of success, status of the bleb, and adverse events. Result. The mean postoperative intraocular pressure was statistically different at 3?m, 6?m, 1?y, 3?y, and 5?y follow-up. The rates of both complete success (P = 0.017) and overall success (P = 0.031) in the Ologen group were significantly higher than those in the mitomycin C group. The difference of the bleb extent and vascularity was statistically significant in both groups. There was no significant difference in postoperative complication. Conclusions. Ologen provides higher rates of surgical success compared with mitomycin C for patients with primary open-angle glaucoma undergoing trabeculectomy. It may be a new, safe, simple, and effective therapeutic approach for treating primary open-angle glaucoma.

  14. Retrieval of atmospheric CO2 from SCIAMACHY nadir spectra considering scattering at thin ice clouds and aerosols

    NASA Astrophysics Data System (ADS)

    Reuter, Maximilian; Buchwitz, Michael; Schneising, Oliver; Heymann, Jens; Bovensmann, Heinrich; Burrows, John P.

    Carbon dioxide is the most important anthropogenic greenhouse gas. Its global increasing mixing ratio in the Earth's atmosphere is the main driver for global warming. However, in spite of its importance, there are still large uncertainties on its global sources and sinks. Highly precise and accurate satellite measurements have the potential to reduce these uncertainties. A new optimal estimation based retrieval scheme has been developed to derive the column averaged CO2 mixing ratio from SCIAMACHY nadir spectra. It uses measurements in the O2 -A absorption band to retrieve scattering information. This information is transported to the CO2 absorption band at 1580nm by simultaneously fitting the spectra measured in both spectral regions. Theoretical studies showed that the developed method has the potential to reduce systematic errors especially due to undetected sub-visible cirrus clouds. We will present results of the new retrieval scheme applied to SCIAMACHY measurements in the surrounding of (at least) two sites: Park Falls, USA and Darwin, Australia.

  15. Recent results in the study of heavy-ion elastic scattering at large angles. [180/sup 0/

    SciTech Connect

    Barrette, J.; Kahana, S.

    1983-01-01

    The observation, a few years ago, of unexpected large cross sections at backward angles in the elastic scattering of mass-asymmetric heavy ion systems gave us hope that we could learn something new and more precise on the properties of the average ion-ion potential. The subsequent observation of broad regular structures in the elastic and inelastic excitation functions near theta/sub cm/ = 180/sup 0/ were also very promising. Numerous models were proposed to explain some or all the observed features. These models can be divided mainly in two groups. Some try to modify directly the average optical potential whereas others associate the observed cross sections to a modification of specific partial waves outside the scope of the optical potential. This separation in two groups is not always clear since as demonstrated adding a Regge pole to a strongly absorbing potential is under some conditions perfectly equivalent to changing the shape of this potential. Similarly the resonances added to an S matrix can be understood as the manifestation of the potential resonances of a completely different optical potential. We describe recent calculations which have been carried on to try to understand the behavior of the data near the barrier.

  16. Rifting in the Northern Tyrrhenian Sea: Results from a combined wide-angle and multichannel seismic study

    NASA Astrophysics Data System (ADS)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; de Franco, R.

    2012-12-01

    Extension in the continental lithosphere leads to the formation of rift basins or finally to passive continental margins where plates fully broke apart. The extensional processes at basins and passive margins are still not fully understood. One of the reasons is that the observed amount of crustal thinning is often much higher than the horizontal extension in the brittle upper crust that can be accounted by faulting. Regarding this objective we present an analysis of two W-E striking depth-migrated multichannel- and wide-angle seismic sections from the Northern Tyrrhenian Sea. The new data were acquired onboard the Spanish R/V Sarmiento de Gamboa and Italian R/V Uraniain spring 2010, within the framework of the MEDOC project. The lines cross the basin from the Corsica and Sardinia margins towards the conjugated Latium/Campania margins (Italy). Along the transects we found two distinct domains distinguishable in tectonic style, heat-flow and crustal thickness: 1) The deep sedimentary Corsica and Sardinia basins in the West which formation started in the Oligocene (~30 Ma) and reveal a fan-shaped sedimentary infill with the Messinian erosional unconformity on top (~5-7 Ma) and 2) rifted crystalline continental crust expressed by horst and graben structures towards the East. These two domains are separated by a deep reaching (~10 km) and westward dipping fault/thrust complex. To quantify the amount of horizontal extension we identified pre-, syn-, and post-tectonic sedimentary units in the northern line A-B (Figure 1), calculated the relative extension factor by large faults as well as balancing the length of the pre-tectonic basement. The Messinian reflector can be well identified throughout the complete section and is therefore an excellent time-marker within the syn-tectonic sequence. The syn-tectonic sequence is limited by a reflector of Pliocene age. The above lying Pleistocene to Quaternary sediments are undisturbed and identified as the post-tectonic sequence. Tomography of first arrivals obtained from refraction and wide-angle seismic data reveals the crustal architecture and thickness of 18 km ± 1 km along the northern profile. We found that the eastern domain is horizontally stretched by >= 30 % and thinned vertically by 40 %. However, we believe that many faults are overlooked due to the partly complexity of Messinian-Tortonian syn-tectonic sequences and that in this young stage of (back-arc) basin evolution the crust evolves in a uniform manner. In this work, we will present these combined seismic data sets and compare them with the C-D transect, which is located ~80 km further south and shows larger stretching factors. Map of the Northern Tyrrehnian Sea and locations of seismic transects.

  17. The retrieval of cloud particle size distributions using occultation and nadir observation geometries

    NASA Astrophysics Data System (ADS)

    Sloan, James; Hu, Jerry; Galkina, Irina; Sioris, Chris

    High cirrus clouds have significant but complex effects on climate due to their capacity to reflect, absorb and emit radiation. Their radiative transfer properties depend on the size and shape of the ice particles of which they are composed. While particle shape information can be obtained only indirectly by space remote sensing, it is possible to obtain size information by direct inversion of remotely sensed optical spectra. Even this approach to the retrieval of particle size information for high-altitude ice clouds, however, remains a very challenging task for space remote sensing. In this presentation, we will discuss methods for the inversion of optical spectra to obtain particle size distributions in clouds. We will also report the application of these methods to space remote sensing measurements of high altitude cirrus clouds. The observations consist of broadband infrared spectra obtained by the ACE FT-IR spectrometer on the SciSat platform. The observation geometry used in the SciSat mission -solar occultation -is capable of good vertical resolution but does not permit the horizontal extent or geographical location of the clouds to be determined. Nadir observation geometries, on the other hand, can give precise geographical locations but are limited by poor signal to noise ratios due to the small thicknesses and low ice particle number densities of the clouds. In the presentation, we will also examine the relative advantages and disadvantages of retrieving cirrus cloud particle size information from both nadir and solar occultation observations and compare the expected signal intensities in each case.

  18. Research on the equivalent nadir point of bistatic SAR with geostationary illuminator and LEO or UAV receivers

    Microsoft Academic Search

    Wang Jingen; Wang Yanfei; Ge Jialong

    2009-01-01

    The problem of how to determine the position of equivalent nadir point of bistatic SAR with geostationary illuminator and low earth orbit (LEO) or unmanned air vehicle (UAV) receivers is very important. Considering high-orbit (or huge-range) characteristic of geostationary bistatic SAR the paper treats the earth surface as an ellipsoid surface and gives several models related to range. After studying

  19. Laser angle sensor development

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.

    1980-01-01

    Electrical and optical parameters were developed for a two axis (pitch/roll) laser angle sensor. The laser source and detector were mounted in the plenum above the model. Two axis optical distortion measurements of flow characteristics in a 0.3 transonic cryogenic tunnel were made with a shearing interferometer. The measurement results provide a basis for estimating the optical parameters of the laser angle sensor. Experimental and analytical information was generated on model windows to cover the reflector. A two axis breadboard was assembled to evaluate different measurement concepts. The measurement results were used to develop a preliminary design of a laser angle sensor. Schematics and expected performance specifications are included.

  20. Low speed rotary aerodynamics of F-18 configuration for 0 deg to 90 deg angle of attack: Test results and analysis

    NASA Technical Reports Server (NTRS)

    Hultberg, R.

    1984-01-01

    Aerodynamic characteristics obtained in a rotational flow environment, utilizing a rotary balance located in the Langley Spin Tunnel, are discussed and presented in tabular form for a 1/10 scale F-18 airplane model. The rotational aerodynamic characteristics were established for the basic airplane, as well as the influence of control deflections and the contribution of airplane components, i.e., body, wing, leading edge extension, horizontal and vertical tails, on these characteristics up to 90 deg angle of attack. Spin equilibrium conditions predicted using the measured data are also presented and compared with spin model and full scale flight results.

  1. Multi-angle Imaging SpectroRadiometer (MISR) on-board calibrator (OBC) in-flight performance studies

    Microsoft Academic Search

    Nadine L. Chrien; Carol J. Bruegge; Robert R. Ando

    2002-01-01

    The Multi-angle Imaging SpectroRadiometer (MISR) consists of nine cameras pointing from nadir to an extreme of 70.5° in the view angle. It is a pushbroom imager with four spectral bands per camera. Instrument specifications call for each camera to be calibrated to an absolute uncertainty of 3% and to within 1% relative to the other cameras. To accomplish this, the

  2. Synchronous generator load angle estimation

    Microsoft Academic Search

    H. Cucek; D. Sumina; N. Svigir

    2010-01-01

    In the paper is proposed a load angle estimation method for synchronous generators. The estimation method is based on synchronous generator corresponding voltage-current vector diagram and parameters of generator, transformer and transmission lines. In addition measurement of the load angle is presented. The estimation results were compared with the measured ones. The estimation method gives satisfactory accuracy for load angles

  3. A New Radiometric Calibration Paradigm for the OMPS Nadir Total Column and Profile Instruments

    NASA Technical Reports Server (NTRS)

    Heath, Donald; Georgiew, Georgi

    2011-01-01

    A fused silica Mie Scattering Diffuser (MSD) has been developed at Ball Aerospace & Technology Corp. that has measured characteristics which could be used to increase the accuracy of the spectral albedo calibration of the Ozone Mapping and Profiler Suite (OMPS) Nadir ozone total column and profile instrument by almost an order of magnitude. Measurements have been made of the optical characteristics on both natural and synthetic forms of fused silica MSDs. Preliminary measurements suggest that MSDs are useable in the solar reflective wavelength region from 250 nm to 3.7 m. To date synthetic and natural MSDs have been irradiated for 60 hours of UV radiation from a solar simulator, and synthetic MSDs have been irradiated with increasing doses of Co-60 gamma rays at 30, 500 krads up to 1.5 Mrads, and 30 krads of 200 MeV protons. The principal effects have been small loses in transmittance at wavelengths < 350 nm. The high energy particle irradiation measurements were provided by Neal Nickles and Dean Spieth.

  4. [Epidemiologic and tonometric results of a multicenter study of 5,872 patients with ocular hypertension or open-angle glaucoma treated with betaxolol].

    PubMed

    Bourgeois, H

    1990-01-01

    A large french multicenter study has been conducted by 750 ophthalmologists with 5,872 patients with open angle chronic glaucoma or intraocular hypertension. The patients were treated twice a day for a period of six months with Betaxolol eye drops, a Beta-1 betablocker product, and cardioselective. Concerning the total population of patients, 35% had a cardiovascular systemic context, 12.1% had a pulmonary systemic context, 5.2% were diabetic patients. Efficacy, systemic tolerance, visual comfort have been evaluated during the study, for each group of patient. After six months of treatment, intra-ocular pressure of the 5,872 patients has been lowered from 22.61 mmHg to 18.25 mmHg. Patients have reported a global efficacy in 97% of cases, a good systemic tolerance in 91% of the cases. The investigations have reported a global efficacy in 96% of cases and a good systemic tolerance in 91%. Ocular comfort has been reported as acceptable by 89% patients and by 92% of the Investigators. The analysis of the results of the study allows us to say that the Beta-blocker-Beta-1 selective eye drop, can be used in treatment of intraocular hypertension or open angle chronic glaucoma with a high range of efficacy and safety. PMID:2263381

  5. Evaluation of the Sensor Data Record from the Nadir Instruments of the Ozone Mapping Profiler Suite (OMPS)

    NASA Technical Reports Server (NTRS)

    Wu, Xiangqian; Liu, Quanhua; Zeng, Jian; Grotenhuis, Michael; Qian, Haifeng; Caponi, Maria; Flynn, Larry; Jaross, Glen; Sen, Bhaswar; Buss, Richard H., Jr.; Johnsen, William; Janz, Scott; Pan, Chunhui; Niu, Jianguo; Beck, Trevor; Beach, Eric; Yu, Wei; Raja, M. K. Rama Varma; Stuhmer, Derek; Cumpton, Daniel; Owen, Cristina; Li, Wen-Hao

    2014-01-01

    This paper evaluates the first 15 months of the Ozone Mapping and Profiler Suite (OMPS) Sensor Data Record (SDR) acquired by the nadir sensors and processed by the National Oceanic and Atmospheric Administration Interface Data Processing Segment. The evaluation consists of an inter-comparison with a similar satellite instrument, an analysis using a radiative transfer model, and an assessment of product stability. This is in addition to the evaluation of sensor calibration and the Environment Data Record product that are also reported in this Special Issue. All these are parts of synergetic effort to provide comprehensive assessment at every level of the products to ensure its quality. It is found that the OMPS nadir SDR quality is satisfactory for the current Provisional maturity. Methods used in the evaluation are being further refined, developed, and expanded, in collaboration with international community through the Global Space-based Inter-Calibration System, to support the upcoming long-term monitoring.

  6. In-flight calibration of the EOS\\/ Multi-angle Imaging SpectroRadiometer (MISR)

    Microsoft Academic Search

    Carol J. Bruegge; Brian G. Chafin; David J. Diner; Robert R. Ando

    2001-01-01

    ABSTRACT The Multi-angle Imaging SpectroRadiometer (MISR) is one of five instruments on the EOS\\/ Terra spacecraft. MISR consists of nine Earth-viewing cameras which continuously acquire global data sets in view perspectives from nadir to 70°. In order to maintain the radiometric calibration ofthe cameras, the instrument is equipped with an on-board calibrator. Spectralon panels, deployed at bi-monthly intervals, reflect sunlight

  7. Optical thickness and effective radius of Arctic boundary-layer clouds retrieved from airborne nadir and imaging spectrometry

    NASA Astrophysics Data System (ADS)

    Bierwirth, E.; Ehrlich, A.; Wendisch, M.; Gayet, J.-F.; Gourbeyre, C.; Dupuy, R.; Herber, A.; Neuber, R.; Lampert, A.

    2013-05-01

    Arctic boundary-layer clouds in the vicinity of Svalbard (78° N, 15° E) were observed with airborne remote sensing and in situ methods. The cloud optical thickness and the droplet effective radius are retrieved from spectral radiance data from the nadir spot (1.5°, 350-2100 nm) and from a nadir-centred image (40°, 400-1000 nm). Two approaches are used for the nadir retrieval, combining the signal from either two or five wavelengths. Two wavelengths are found to be sufficient for an accurate retrieval of the cloud optical thickness, while the retrieval of droplet effective radius is more sensitive to the number of wavelengths. Even with the comparison to in-situ data, it is not possible to definitely answer the question which method is better. This is due to unavoidable time delays between the in-situ measurements and the remote-sensing observations, and to the scarcity of vertical in-situ profiles within the cloud.

  8. Angle performance on optima MDxt

    SciTech Connect

    David, Jonathan; Kamenitsa, Dennis [Axcelis Technologies, Inc., 108 Cherry Hill Dr, Beverly, MA 01915 (United States)

    2012-11-06

    Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt's angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16 Degree-Sign (1{sigma}). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1 Degree-Sign (1{sigma}).

  9. Results of a study of Mach number and Reynolds number effects on the lee side vortex flow field characteristics of an ogive-cylinder-frustum-cylinder at angles of attack to 25 degrees, volume 1

    NASA Technical Reports Server (NTRS)

    Foley, J. E.

    1972-01-01

    An experimental program was conducted to survey the lee side vortex flow field about an ogive-cylinder-frustum-cylinder at angles of attack to 25 degrees for two Reynolds numbers at Mach number 0.8, and one Reynolds number at Mach number 1.96. The data were obtained using miniature 5-port conical pressure probes calibrated for angle of attack and roll angle over a Mach number range of 0.6 to 3.0. The results are presented here as local flow field properties and circulation strengths for various body stations.

  10. On Orbit Measurement of Response vs. Scan Angle for the Infrared Bands on TRMM/VIRS

    NASA Technical Reports Server (NTRS)

    Barnes, William L.; Lyu, Cheng-Hsuan; Barnes, Robert A.

    1999-01-01

    The Visible and Infrared Scanner on the Tropical Rainfall Measuring Mission (TRMM/VIRS) is a whiskbroom imaging radiometer with two reflected solar bands and three emissive infrared bands. All five detectors are on a single cooled focal plane. This configuration necessitated the use of a paddlewheel scan mirror to avoid the effects of focal plane rotation that arise when using a scan mirror that is inclined to its axis of rotation. System radiometric requirements led to the need for protected silver as the mirror surface. Unfortunately, the SiO(x) coatings currently used to protect silver from oxidation introduce a change in reflectance with angle of incidence (AOI). This AOI dependence results in a modulation of system level response with scan angle. Measurement of system response vs. scan angle (RVS) was not difficult for the VIRS reflected solar bands, but attaining the required accuracy for the IR bands in the laboratory was not possible without a large vacuum chamber and a considerable amount of custom designed testing apparatus. Therefore, the decision was made to conduct the measurement on-orbit. On three separate occasions, the TRMM spacecraft was rotated about its pitch axis and, after the nadir view passed over the Earth's limb, the VIRS performed several thousand scans while viewing deep space. The resulting data has been analyzed and the RVS curves generated for the three IR bands are being used in the VIRS radiometric calibration algorithm. This, to our knowledge, the first time this measurement has been made on-orbit. Similar measurements are planned for the EOS-AM and EOS-PM MODIS sensors and are being considered for several systems under development. The VIRS on-orbit results will be compared to VIRS and MODIS system level laboratory measurements, MODIS scan mirror witness sample measurements and modeled data.

  11. What's the Angle?

    NSDL National Science Digital Library

    American Museum of Natural History

    2002-01-01

    This activity helps learners understand how the angle of the Sun affects temperatures around the globe. After experimenting with a heat lamp and thermometers at differing angles, learners apply what they learned to explain temperature variations on Earth. The printable six-page handout includes a series of inquiry-based questions to get learners thinking about what they already know about temperature patterns, detailed experiment directions, and a worksheet that helps learners use the experiment results to gain a deeper understanding of seasonal temperature changes and why Antarctica is always cold.

  12. Second-Generation Multi-Angle Imaging Spectroradiometer

    NASA Technical Reports Server (NTRS)

    Macenka, Steven; Hovland, Larry; Preston, Daniel; Zellers, Brian; Downing, Kevin

    2004-01-01

    A report discusses an early phase in the development of the MISR-2 C, a second, improved version of the Multi-angle Imaging SpectroRadiometer (MISR), which has been in orbit around the Earth aboard NASA's Terra spacecraft since 1999. Like the MISR, the MISR-2 would contain a pushbroom array of nine charge-coupled- device (CCD) cameras one aimed at the nadir and the others aimed at different angles sideways from the nadir. The major improvements embodied in the MISR-2 would be the following: A new folded-reflective-optics design would render the MISR-2 only a third as massive as the MISR. Smaller filters and electronic circuits would enable a reduction in volume to a sixth of that of the MISR. The MISR-2 would generate images in two infrared spectral bands in addition to the blue, green, red, and near-infrared spectral bands of the MISR. Miniature polarization filters would be incorporated to add a polarization-sensing capability. Calibration would be performed nonintrusively by use of a gimbaled tenth camera. The main accomplishment thus far has been the construction of an extremely compact all-reflective-optics CCD camera to demonstrate feasibility.

  13. What Is the Angle?

    NSDL National Science Digital Library

    This activity will help students understand how the angle of the Sun affects temperatures around the globe. After experimenting with a heat lamp and thermometers at differing angles, students apply what they learned to explain temperature variations on Earth. The printable six-page handout includes a series of inquiry-based questions to get students thinking about what they already know about temperature patterns, detailed experiment directions, and a worksheet that will help students use the experiment results to gain a deeper understanding of seasonal temperature changes and why Antarctica is always so cold. The students will explore all the angles of sunlight with a few thermometers and a heat lamp and understand why there is such a dramatic temperature change between the equator and the South Pole.

  14. The 1990 Brooks Range, Alaska, seismic experiment: Results from vertical-incidence and wide-angle reflection data and refraction data

    SciTech Connect

    Fuis, G.S.; Lutter, W.J. (Geological Survey, Menlo Park, CA (United States)); Levander, A.R.; Wissinger, E.S. (Rice Univ., Houston, TX (United States))

    1993-04-01

    From the seismic data collected in 1990 across the Brooks Range (BR), arctic Alaska, the authors have produced a low-fold, vertical-incidence-reflection (CMP) image and a velocity model of this Mesozoic/Tertiary fold-and-thrust belt. Although the CMP image and velocity model reveal major features, both are limited: reflections are sparse in some regions and velocity in the upper crust is not well constrained below about 5 km. Wide-angle reflections (WR) are used to provide additional constraints, especially for the CMP image. These WR can be traced over much longer distances and with much less ambiguity than is possible on the CMP image alone. WR also provide additional, albeit weak, velocity constraints. Major results are: (1) in the northern BR, the CMP image and WR both reveal two zones of gently south-dipping, echelon reflections, in the upper and middle crust, which are interpreted as the basal part of the Endicott Mts allochthon and the basal part of allochthonous North Slope rocks, respectively; (2) in the middle crust of the southern BR, gently north-dipping reflections are seen in the CMP image to truncate or diverge northward from south-dipping reflections in overlying terranes, but they can not be traced into the central BR; (3) in the central BR, reflections at the base of the Endicott Mts. allochthon are folded across the Doonerak antiform, and from the antiformal axis southward, the echelon reflections above the master decollement deform into a series of stretched S's, defining lens-shaped, duplexed bodies of rock; (4) Moho deepens from 35-km depth south of the Brooks Range to 46-km depth in the northern Brooks Range, the highest part, and shoals abruptly to 35-km beneath the North Slope.

  15. Off-nadir antenna bias correction using Amazon rain sigma(0) data

    NASA Technical Reports Server (NTRS)

    Birrer, I. J.; Dome, G. J.; Sweet, J.; Berthold, G.; Moore, R. K.

    1982-01-01

    The radar response from the Amazon rain forest was studied to determine the suitability of this region for use as a standard target to calibrate a scatterometer like that proposed for the National Oceanic Satellite System (NOSS). Backscattering observations made by the SEASAT Scatterometer System (SASS) showed the Amazon rain forest to be a homogeneous, azimuthally-isotropic, radar target which was insensitive to polarization. The variation with angle of incidence was adequately modeled as scattering coefficient (dB) = a theta b with typical values for the incidence-angle coefficient from 0.07 to 0.15 dB/deg. A small diurnal effect occurs, with measurements at sunrise being 0.5 dB to 1 dB higher than the rest of the day. Maximum-likelihood estimation algorithms presented here permit determination of relative bias and true pointing angle for each beam. Specific implementation of these algorithms for the proposed NOSS scatterometer system is also discussed.

  16. Off-nadir antenna bias correction using Amazon rain forest sigma deg data. [Brazil

    NASA Technical Reports Server (NTRS)

    Birrer, I. J.; Bracalente, E. M.; Dome, G. J.; Sweet, J.; Berthold, G.; Moore, R. K. (principal investigators)

    1981-01-01

    The radar response from the Amazon rain forest was studied to determine the suitability of this region for use as a standard target to calibrate a scatterometer like that proposed for the National Ocean Satellite System (NOSS). Backscattering observations made by the SEASAT-1 scatterometer system show the Amazon rain forest to be a homogeneous, azimuthally-isotropic, radar target which is insensitive to polarization. The variation with angle of incidence may be adequately modeled as sigma deg (dB) = alpha theta + beta with typical values for the incidence-angle coefficient from 0.07 dB deg to 0.15 dB/deg. A small diurnal effect occurs, with measurements at sunrise being 0.5 dB to 1 dB higher than the rest of the day. Maximum likelihood estimation algorithms are presented which permit determination of relative bias and true pointing angle for each beam. Specific implementation of these algorithms for the proposed NOSS scatterometer system is also discussed.

  17. PSA Nadir of <0.5 ng/mL Following Brachytherapy for Early-Stage Prostate Adenocarcinoma is Associated With Freedom From Prostate-Specific Antigen Failure

    SciTech Connect

    Ko, Eric C. [Department of Radiation Oncology, Mount Sinai Medical Center, New York, NY (United States); Stone, Nelson N. [Department of Radiation Oncology, Mount Sinai Medical Center, New York, NY (United States); Department of Urology, Mount Sinai Medical Center, New York, NY (United States); Stock, Richard G., E-mail: Richard.Stock@mountsinai.org [Department of Radiation Oncology, Mount Sinai Medical Center, New York, NY (United States)

    2012-06-01

    Purpose: Because limited information exists regarding whether the rate or magnitude of PSA decline following brachytherapy predicts long-term clinical outcomes, we evaluated whether achieving a prostate-specific antigen (PSA) nadir (nPSA) <0.5 ng/mL following brachytherapy is associated with decreased PSA failure and/or distant metastasis. Methods and Materials: We retrospectively analyzed our database of early-stage prostate adenocarcinoma patients who underwent brachytherapy, excluding those receiving androgen-deprivation therapy and those with <2 years follow-up. Median and mean pretreatment PSA were 6 ng/mL and 7.16 ng/mL, respectively. By clinical stage, 775 were low risk ({<=}T2a), 126 were intermediate risk (T2b), and 20 were high risk (>T2b). By Gleason score, 840 were low risk ({<=}6), 71 were intermediate risk (7), and 10 were high risk (>7). Patients were treated with brachytherapy only (I-125, n = 779, or Pd-103, n = 47), or brachytherapy + external-beam radiation therapy (n = 95). Median follow-up was 6.3 years. We noted whether nPSA <0.5 ng/mL was achieved and the time to achieve this nadir and tested for associations with pretreatment risk factors. We also determined whether this PSA endpoint was associated with decreased PSA failure or distant metastasis. Results: Absence of high-risk factors in clinical stage ({<=}T2b), Gleason score ({<=}7), and pretreatment PSA ({<=}20 ng/mL) was significantly associated with achieving nPSA <0.5 ng/mL. By Kaplan-Meier analysis, patients achieving nPSA <0.5 ng/mL had significantly higher long-term freedom from biochemical failure (FFBF) than nonresponders (5-year FFBF: 95.2 {+-} 0.8% vs. 71.5 {+-} 6.7%; p < 0.0005). Among responders, those who achieved nPSA <0.5 ng/mL in {<=}5 years had higher FFBF than those requiring >5 years (5-year FFBF: 96.7 {+-} 0.7% vs. 80.8 {+-} 4.6%; p < 0.0005). On multivariate analysis, patients who achieved nPSA <0.5 ng/mL in {<=}5 years had significantly higher FFBF than other patients. Conclusions: Pretreatment risk factors (clinical tumor stage, Gleason score, pretreatment PSA) strongly predict for patients achieving nPSA <0.5 ng/mL following brachytherapy, and this cohort had significantly higher long-term FFBF.

  18. Effects of skylight polarization, cloudiness, and view angle on the detection of oil on water.

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Arvesen, J. C.

    1971-01-01

    Three passive radiometric techniques, which use the contrast of sunlight reflected and backscattered from oil and water in specific wavelength regions, have potential application for remote sensing of oil spills. These techniques consist of measuring (1) total radiance, (2) the polarization components (normal and parallel) of radiance, and (3) the difference between the normal and parallel components. In this paper, the best view directions for these techniques are evaluated, conclusions are drawn as to the most promising technique, and explanations are developed to describe why previous total-radiance measurements yielded highest contrast between oil and water under overcast skies. The technique based on measurement of only the normal polorization component appears to be the most promising. The differential technique should be further investigated because of its potential to reduce the component of backscattered light from below the surface of the water. Measurements should be made about 45 deg nadir view angle in the direction opposite the sun. Overcast sky conditions provide a higher intensity of skylight relative to clear sky conditions and a lower intensity of backscatter within the water relative to surface reflectance. These factors result in higher contrast between oil and water under overcast skies.

  19. Results from 1984 airborne Doppler lidar wind measurement program. Flight 6: Analysis of line-of-sight elevation angle errors and apparent Doppler velocities

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry

    1987-01-01

    During the summer of 1984 the Marshall Space Flight Center's Airborne Doppler Lidar System (ADLS) made a series of wind measurements in the California Central Valley. This study quantifies the lidar beam angle errors and velocity errors through analysis of ground return signals. Line-of-sight elevation (LOSE) angle errors are under 1 deg. Apparent Doppler ground velocities, as large as 2m/s, are considerably less than in a previous flight experiment in 1981. No evidence was found of a Schuler resonance phenomenon common to inertial navigation systems (INS), however the aperiodic nature of the apparent velocities implies an error in the INS-derived ground speeds. Certain features and subtleties in the ground returns are explained in terms of atmospheric structure and characteristics of the ADLS hardware and software. Finally, least squares and low-pass filtering techniques are suggested for eliminating errors during post-processing.

  20. Wide angle X-ray scattering (WAXS) study of “two-line” ferrihydrite structure: Effect of arsenate sorption and counterion variation and comparison with EXAFS results

    Microsoft Academic Search

    G. A. Waychunas; C. C. Fuller; B. A. Rea; J. A. Davis

    1996-01-01

    Wide angle X-ray scattering (WAXS) measurements have been made on a suite of “two-line” ferrihydrite (FHY2) samples containing varying amounts of coprecipitated arsenate. Samples prepared at pH 8 with counter ions chloride, nitrate, and a mixture of both also were examined. The raw WAXS scattering functions show that “two-line” ferrihydrite actually has a large number of non-Bragg (i.e., diffuse scattering)

  1. [Mid-term results of a double-blind study comparing metipranolol to timolol in the treatment of primary open-angle glaucoma].

    PubMed

    Ecoffet, M; Demailly, P

    1987-01-01

    A study on 26 patients with chronic angle glaucoma was completed after 17 weeks. The IOP was satisfactorily stabilized on patients treated with Metipranolol drops. In the Timolol group, the IOP rose again after the 9th week and, at the completion of the study, the difference between the averages of the two groups is significant. No systemic effect was noted as well in the Metipranolol group as in the Timolol group. PMID:2891740

  2. MISR Multi-angle Views of Sunday Morning Fires

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Hot, dry Santa Ana winds began blowing through the Los Angeles and San Diego areas on Sunday October 21, 2007. Wind speeds ranging from 30 to 50 mph were measured in the area, with extremely low relative humidities. These winds, coupled with exceptionally dry conditions due to lack of rainfall resulted in a number of fires in the Los Angeles and San Diego areas, causing the evacuation of more than 250,000 people.

    These two images show the Southern California coast from Los Angeles to San Diego from two of the nine cameras on the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the NASA EOS Terra satellite. These images were obtained around 11:35 a.m. PDT on Sunday morning, October 21, 2007 and show a number of plumes extending out over the Pacific ocean. In addition, locations identified as potential hot spots from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the same satellite are outlined in red.

    The left image is from MISR's nadir looking camera and the plumes appear very faint. The image on the right is from MISR's 60o forward looking camera, which accentuates the amount of light scattered by aerosols in the atmosphere, including smoke and dust. Both these images are false color and contain information from MISR's red, green, blue and near-infrared wavelengths, which makes vegetated land appear greener than it would naturally. Notice in the right hand image that the color of the plumes associated with the MODIS hot spots is bluish, while plumes not associated with hot spots appear more yellow. This is because the latter plumes are composed of dust kicked up by the strong Santa Ana winds. In some locations along Interstate 5 on this date, visibility was severely reduced due to blowing dust. MISR's multiangle and multispectral capability give it the ability to distinguish smoke from dust in this situation.

    The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These images were generated from a portion of the imagery acquired during Terra orbit 41713, and use data from blocks 63 to 66 within World Reference System-2 path 40.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. The MISR data were obtained from the NASA Langley Research Center Atmospheric Science Data Center. JPL is a division of the California Institute of Technology.

  3. Angles, scales and parametric renormalization

    E-print Network

    Francis Brown; Dirk Kreimer

    2011-12-06

    We decompose renormalized Feynman rules according to the scale and angle dependence of amplitudes. We use parametric representations such that the resulting amplitudes can be studied in algebraic geometry.

  4. On-orbit measurement of response vs. scan angle for the infrared bands on TRMM/VIRS

    NASA Astrophysics Data System (ADS)

    Barnes, William L.; Lyu, Cheng-Hsuan; Barnes, Robert A.

    1999-12-01

    The Visible and Infrared Scanner on the Tropical Rainfall Measuring Mission (TRMM/VIRS) is whiskbroom imaging radiometer with two reflected solar bands and three emissive infrared bands. All five detectors are on a single cooled focal plane. This configuration necessitated the use of a paddlewheel scan mirror to avoid the effects of focal plane rotation that arise when using a scan mirror that is inclined to its axis of rotation. System radiometric requirements led to the need for protected silver as the mirror surface. Unfortunately, the SiOx coatings currently used to protect silver from oxidation introduce a change in reflectance with angle of incidence (AOI). This AOI dependence results in a modulation of system level response with scan angle. Measurement of system response vs. scan angle (RVS) was not difficult for the VIRS reflected solar bands, but attaining the required accuracy for the IR bands in the laboratory was not possible without a large vacuum chamber and a considerable amount of custom designed testing apparatus. Therefore, the decision was made to conduct the measurement on-orbit. On three separate occasions, the TRMM spacecraft was rotated about its pitch axis and, after the nadir view passed over the Earth's limb, the VIRS performed several thousand scans while viewing deep space. The resulting data has been analyzed and the RVS curves generated for the three IR bands are being used in the VIRS radiometric calibration algorithm. This, to our knowledge, the first time this measurement has been made on-orbit. Similar measurements are planned for the EOS-AM and EOS-PM MODIS sensors and are being considered for several systems under development. The VIRS on-orbit results will be compared to VIRS and MODIS system level laboratory measurements, MODIS scan mirror witness sample measurements and modeled data.

  5. Small Angle Neutron Scattering

    SciTech Connect

    Urban, Volker S [ORNL

    2012-01-01

    Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.

  6. Prostate biopsy status and PSA nadir level as early surrogates for treatment failure: analysis of a prostate cancer randomized radiation dose escalation trial

    Microsoft Academic Search

    Alan Pollack; Gunar K Zagars; John A Antolak; Deborah A Kuban; Isaac I Rosen

    2002-01-01

    Purpose: A positive biopsy after external beam radiotherapy in patients free of any evidence of treatment failure is not synonymous with eventual recurrence. Although biopsy positivity is a predictor of outcome, the utility of biopsy status as a surrogate end point, the effect of radiation dose on biopsy status, and the interrelationships of these associations to prostate-specific antigen (PSA) nadir

  7. Regression coefficient maps showing that Nadir CD4+ count is correlated with regional white matter volumes (FDR q=0.05, critical P=0.03)

    E-print Network

    Thompson, Paul

    brain volumes and (1) demographic variables: age, sex (2) immune system measures: current and nadir CD4 in the frontal white matter are correlated with regional white matter volumes (FDR q=0.05, critical P=0.03) Brain, but the brain changes underlying this cognitive decline are still poorly understood. In patients with HIV

  8. Hysteresis during contact angles measurement.

    PubMed

    Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle. PMID:20060981

  9. Laser angle measurement system

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.; Wilbert, R. E.

    1980-01-01

    The design and fabrication of a laser angle measurement system is described. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the mode. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. Optical and electrical schematics, system maintenance and operation procedures are included, and the results of a demonstration test are given.

  10. Multi-Angle View of the Canary Islands

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A multi-angle view of the Canary Islands in a dust storm, 29 February 2000. At left is a true-color image taken by the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. This image was captured by the MISR camera looking at a 70.5-degree angle to the surface, ahead of the spacecraft. The middle image was taken by the MISR downward-looking (nadir) camera, and the right image is from the aftward 70.5-degree camera. The images are reproduced using the same radiometric scale, so variations in brightness, color, and contrast represent true variations in surface and atmospheric reflectance with angle. Windblown dust from the Sahara Desert is apparent in all three images, and is much brighter in the oblique views. This illustrates how MISR's oblique imaging capability makes the instrument a sensitive detector of dust and other particles in the atmosphere. Data for all channels are presented in a Space Oblique Mercator map projection to facilitate their co-registration. The images are about 400 km (250 miles)wide, with a spatial resolution of about 1.1 kilometers (1,200 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  11. External Beam Radiotherapy for Clinically Localized Hormone-Refractory Prostate Cancer: Clinical Significance of Nadir Prostate-Specific Antigen Value Within 12 Months

    SciTech Connect

    Ogawa, Kazuhiko [Department of Radiology, University of the Ryukyus, Okinawa, Osaka (Japan)], E-mail: kogawa@med.u-ryukyu.ac.jp; Nakamura, Katsumasa [Department of Clinical Radiology, Fukuoka University, Fukuoka (Japan); Sasaki, Tomonari [Department of Radiation Oncology, National Kyushu Center, Fukuoka (Japan); Onishi, Hiroshi [Department of Radiology, Yamanashi University, Yamanashi (Japan); Koizumi, Masahiko [Department of Radiation Oncology, Osaka University, Osaka (Japan); Shioyama, Yoshiyuki [Department of Clinical Radiology, Kyushu University, Fukuoka (Japan); Araya, Masayuki [Department of Radiology, Yamanashi University, Yamanashi (Japan); Mukumoto, Nobutaka M.S. [Department of Medical Physics and Engineering, Osaka University, Osaka (Japan); Mitsumori, Michihide [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University, Kyoto (Japan); Teshima, Teruki [Department of Medical Physics and Engineering, Osaka University, Osaka (Japan)

    2009-07-01

    Purpose: To analyze retrospectively the results of external beam radiotherapy for clinically localized hormone-refractory prostate cancer and investigate the clinical significance of nadir prostate-specific antigen (PSA) value within 12 months (nPSA12) as an early estimate of clinical outcomes after radiotherapy. Methods and Materials: Eighty-four patients with localized hormone-refractory prostate cancer treated with external beam radiotherapy were retrospectively reviewed. The total radiation doses ranged from 30 to 76 Gy (median, 66 Gy), and the median follow-up period for all 84 patients was 26.9 months (range, 2.7-77.3 months). Results: The 3-year actuarial overall survival, progression-free survival (PFS), and local control rates in all 84 patients after radiotherapy were 67%, 61%, and 93%, respectively. Although distant metastases and/or regional lymph node metastases developed in 34 patients (40%) after radiotherapy, local progression was observed in only 5 patients (6%). Of all 84 patients, the median nPSA12 in patients with clinical failure and in patients without clinical failure was 3.1 ng/mL and 0.5 ng/mL, respectively. When dividing patients according to low (<0.5 ng/mL) and high ({>=}0.5 ng/mL) nPSA12 levels, the 3-year PFS rate in patients with low nPSA12 and in those with high nPSA12 was 96% and 44%, respectively (p < 0.0001). In univariate analysis, nPSA12 and pretreatment PSA value had a significant impact on PFS, and in multivariate analysis nPSA12 alone was an independent prognostic factor for PFS after radiotherapy. Conclusions: External beam radiotherapy had an excellent local control rate for clinically localized hormone-refractory prostate cancer, and nPSA12 was predictive of clinical outcomes after radiotherapy.

  12. What's Your Angle?

    NSDL National Science Digital Library

    2010-01-01

    In this activity, students devise procedures for using a protractor to measure the number of degrees in an angle, and use inductive reasoning to develop "angle sense." Then they describe circumstances and careers that require a working knowledge of angles and their measurements.

  13. Angles All Around

    NSDL National Science Digital Library

    Mrs. Bennett

    2011-12-14

    Standard: Identify and measure right, obtuse, and acute angles. This is a two day activity. OBJECTIVE: We have learned about five different types of angles: right, acute, obtuse, straight, and reflex. We have also learned how to use a protractor to measure angles. With this lesson, you will practice what ...

  14. Development of an approach for generation of temporally complete daily nadir MODIS reflectance time series

    Microsoft Academic Search

    Junchang Ju; David P. Roy; Yanmin Shuai; Crystal Schaaf

    2010-01-01

    Consistent, spatially and temporally complete reflectance time series are required for reliable terrestrial monitoring. The Moderate Resolution Imaging Spectroradiometer (MODIS), like other polar-orbiting wide field of view satellite sensors, can provide global observations on a nearly daily basis, but the sparseness of valid observations due to cloud, residual atmospheric effects, and sensor anomalies, may result in gaps in the derived

  15. Cerebellopontine Angle Lipoma

    PubMed Central

    Schuhmann, Martin U.; Lüdemann, Wolf O.; Schreiber, Hartwig; Samii, Madjid

    1997-01-01

    Intracranial lipomas in an infratentorial and extra-axial location are extremely rare. The presented case of an extensive lipoma of the cerebellopontine angle (CPA) represents 0.05% of all CPA tumors operated on in our department from 1978 to 1996. The lipoma constitutes an important differential diagnosis because the clinical management differs significantly from other CPA lesions. The clinical presentation and management of the presented case are analyzed in comparison to all previously described cases of CPA lipomas. The etiology and the radiological features of CPA lipomas are reviewed and discussed. CPA lipomas are maldevelopmental lesions that may cause slowly progressive symptoms. Neuroradiology enables a reliable preoperative diagnosis. Attempts of complete lipoma resection usually result in severe neurological deficits. Therefore, we recommend a conservative approach in managing these patients. Limited surgery is indicated if the patient has an associated vascular compression syndrome or suffers from disabling vertigo. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:17171031

  16. Seismic structure and crustal nature of the geological provinces off the SW Iberian margin: results of the NEAREST-SEIS wide-angle seismic survey

    NASA Astrophysics Data System (ADS)

    Sallares, V.; Martinez, S.; Gailler, A.; Gutscher, M.; Bartolome, R.; Gracia, E.; Diaz, J.

    2010-12-01

    The region offshore the SW Iberian margin hosts the present-day NW-SE plate convergence between the European and African Plates causing continuous seismic activity of moderate magnitude. In autumn 2008 a Spanish-French team carried out a wide-angle seismic survey in the area (NEAREST-SEIS cruise), in the framework of the EU-funded NEAREST project. During the survey two long profiles were acquired using a pool of 36 Ocean Bottom Seismometers (OBS), to provide information about the crustal structure and nature of the different geological provinces, and to reveal the deep geometry of the main fault interfaces. A total of 30 OBS were deployed along profile P1, which is 356 km long and trends NW-SE from the Tagus abyssal plain (TAP), crossing the Gorringe bank (GB), the Horseshoe abyssal plain (HAP) and the Coral Patch Ridge (CPR), up to the thrust-and-fold belt of the Seine abyssal plain (SAP). The inverted model along this profile show four different domains. In the TAP a 3-4 km-thick, low velocity sedimentary layer covers the basement, which shows a velocity >7 km/s just 2-3 km below its top, similarly to that of the basement outcropping in the Gorringe bank. In the HAP the sedimentary cover is thicker, showing an upper unit with low velocity corresponding to the Horseshoe gravitational unit, on top of a higher velocity lower unit, which may represent the highly consolidated Mesozoic sedimentary sequence, with a total thickness of 5 km. The basement shows the same velocity distribution as in TAP and GB, suggesting a common nature and origin. According to its seismic structure, we interpret this basement as highly serpentinized, exhumed mantle. In contrast, the CPR and SAP show evidences for the presence of a well-developed, 6-7 km-thick oceanic crust, underlying the sedimentary sequence. Profile P2 is 256 km long, and trends S-N from the easternmost SAP beyond the NW Moroccan margin, crossing the Gulf of Cadiz imbricated wedge and the Portimao bank ending at the Iberian margin shelf. 15 OBS and 7 land-stations were deployed along this profile. The inverted model shows two main domains: In the southern half, there is a 3-4 km-thick cover of low velocity sediments, which represents the western edge of the wedge that covers the internal Gulf of Cadiz, overlying a 7-8 km-thick oceanic crust. According to recent tectonic reconstructions, this crustal segment should have been emplaced there during the early phase of continental spreading between Iberia and Africa, in the context of Mesozoic Atlantic spreading. The northern part of P2 displays a relatively sharp ocean-continent transition zone concentrated in a ˜50 km-wide band, that ends with the ˜30 km-thick continental crust of the SW Iberian shelf.

  17. Seismic structure of the main geological provinces off the SW Iberian margin: first results from the NEAREST-SEIS wide-angle seismic survey

    NASA Astrophysics Data System (ADS)

    Sallarès, Valentí; Martínez-Loriente, Sara; Gailler, Audrey; Bartolomé, Rafael; Gutscher, Marc-André; Graindorge, David; Lia Grácia, Eulà; Díaz, Jordi

    2010-05-01

    The region offshore the SW Iberian margin hosts the present-day NW-SE plate convergence between the European and African Plates at a rate of 4.5 mm/yr, fact that causes continuous seismic activity of moderate magnitude. In autumn 2008 a Spanish-French team carried out a refraction and wide-angle reflection seismic survey in the area (NEAREST-SEIS cruise), in the framework of the EU, FP6-funded NEAREST project. During the survey two long seismic profiles were acquired using a pool of 36 Ocean Bottom Seismometers (OBS), with the objectives of providing information about the geometry of the crust-mantle boundary and the physical properties of the crust, revealing the deep geometry of the main fault interfaces, and identifying the nature of the basement and the limits of the different geological provinces in the region. A total of 30 OBS were deployed along profile P1, which is 356 km long and trends NW-SE from the Tagus abyssal plain (TAP), crossing the Gorringe bank (GB), the Horseshoe abyssal plain (HAP) and the Coral Patch Ridge (CPR), up to the thrust-and-fold belt of the Seine abyssal plain (SAP). The acquired data were modeled by joint refraction and reflection travel time inversion, following a layer-stripping strategy. The inverted model show four well-differentiated domains in terms of its seismic structure: In the TAP a 3-4 km-thick, low velocity sedimentary layer covers the basement, which shows a remarkably high velocity (>7 km/s), similar to that of the basement outcropping in the Gorringe bank. In the HAP the sedimentary cover is thicker, showing an upper unit with low velocity corresponding to the Horseshoe gravitational unit, on top of a higher velocity lower unit, which may represent the highly consolidated Mesozoic sedimentary sequence. The thickness of the two units together exceeds 5 km. The basement shows the same velocity distribution as in TAP and GB, suggesting a common nature and origin. According to its seismic structure, and considering that there is no evidence for the presence of a basal reflector (e.g. Moho) in the record sections, we interpret this basement as highly serpentinized, exhumed mantle. In contrast, the CPR and SAP show evidences for the presence of a well-developed, 6-7 km-thick oceanic crust, underlying the 2-3 km-thick, moderate velocity, Mesozoic sedimentary sequence. Profile P2 is 256 km long, and trends S-N from the easternmost SAP beyond the NW Moroccan margin, crossing the Gulf of Cadiz imbricated wedge and the Portimao bank ending at the Iberian margin shelf. 15 OBS and 7 land-stations were deployed along this profile, and the recorded data were modeled following the same approach and strategy as for P1. The inverted model shows two main domains: In the southern half, there is a 3-4 km-thick cover of low velocity sediments, which represents the western edge of the sedimentary wedge that covers the internal Gulf of Cadiz, overlying a 7-8 km-thick oceanic crust. According to recent tectonic reconstructions, this crustal segment should have been emplaced there during the early phase of continental spreading between Iberia and Africa, in the context of Mesozoic Atlantic spreading. The northern part of P2 displays a relatively sharp ocean-continent transition zone concentrated in a ~50 km-wide band, that ends with the ~30 km-thick continental crust of the SW Iberian shelf.

  18. Special Angle Pairs Discovery Activity

    NSDL National Science Digital Library

    Barbara Henry

    2012-04-16

    This lesson uses a discovery approach to identify the special angles formed when a set of parallel lines is cut by a transversal. During this lesson students identify the angle pair and the relationship between the angles. Students use this relationship and special angle pairs to make conjectures about which angle pairs are considered special angles.

  19. Polygon Angle Applet

    NSDL National Science Digital Library

    Nicholas Exner

    2000-05-31

    This interactive Java applet supports the investigation of the relationship between the number of vertices of a polygon and its interior angle sum. Learners choose and locate the vertices, the angle measures are displayed, and then the student can drag the measures into a circle to see them summed relative to 360 degrees.

  20. Data Plots of Run I - III Results from SLAC E-158: A precision Measurement of the Weak Mixing Angle in Moller Scattering

    DOE Data Explorer

    Three physics runs were made in 2002 and 2003 by E-158. As a result, the E-158 Collaboration announced that it had made "the first observation of Parity Violation in electron-electron (Moller) scattering). This precise Parity Violation measurement gives the best determination of the electron's weak charge at low energy (low momentum transfer between interacting particles). E158's measurement tests the predicted running (or evolution) of this weak charge with energy, and searches for new phenomena at TeV energy scales (one thousand times the proton-mass energy scale).[Copied from the experiment's public home page at http://www-project slac.stanford.edu/3158/Default.htm] See also the E158 page for collaborators at http://www.slac.stanford.edu/exp/e158/. Both websites provide data and detailed information.

  1. The measurement of boundary layers on a compressor blade in cascade at high positive incidence angle. 1: Experimental techniques and results

    NASA Technical Reports Server (NTRS)

    Deutsch, S.; Zierke, W. C.

    1986-01-01

    Measurements of the mean velocity and turbulence intensity were made using a one-component laser Doppler velocimeter in the boundary layer and near wake about a double circular arc, compressor blade in cascade. The measurements were made at a chord Reynolds number of 500,000. Boundary layer measurements on the pressure surface indicate a transition region over the last 40% of the chord. A small separation bubble near the leading edge of the suction surface results in an immediate transition from laminar to turbulent flow. The non-equilibrium turbulent boundary layer separates near the trailing edge of the suction surface. Similarity of the outer region of the turbulent boundary layer ceases to exist in the separated region. Also, similarity does not hold in the near-wake region, a region which includes negative mean velocities because of the separation near the trailing edge on the suction surface.

  2. Dynamic contact angle measurements on superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Kim, Jeong-Hyun; Kavehpour, H. Pirouz; Rothstein, Jonathan P.

    2015-03-01

    In this paper, the dynamic advancing and receding contact angles of a series of aqueous solutions were measured on a number of hydrophobic and superhydrophobic surfaces using a modified Wilhelmy plate technique. Superhydrophobic surfaces are hydrophobic surfaces with micron or nanometer sized surface roughness. These surfaces have very large static advancing contact angles and little static contact angle hysteresis. In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth hydrophobic Teflon surface were found to obey the scaling with capillary number predicted by the Cox-Voinov-Tanner law, ?D3 ? Ca. The response of the dynamic contact angle on the superhydrophobic surfaces, however, did not follow the same scaling law. The advancing contact angle was found to remain constant at ?A = 160?, independent of capillary number. The dynamic receding contact angle measurements on superhydrophobic surfaces were found to decrease with increasing capillary number; however, the presence of slip on the superhydrophobic surface was found to result in a shift in the onset of dynamic contact angle variation to larger capillary numbers. In addition, a much weaker dependence of the dynamic contact angle on capillary number was observed for some of the superhydrophobic surfaces tested.

  3. Constraints on crustal composition beneath a metamorphic core complex: results from 3-component wide-angle seismic data along the eastern flank of the Ruby Mountains, Nevada

    NASA Astrophysics Data System (ADS)

    Satarugsa, P.; Johnson, R. A.

    2000-12-01

    Metamorphic core complexes expose rocks deformed at deep upper to middle crustal levels during extreme crustal extension. However, mechanisms of crustal extension and exhumation of core complexes remain to be fully understood. Detailed study of crustal velocity structure and inferences about the composition of the crust beneath core complexes (and nearby) provide useful constraints on core-complex evolution. P- and S-wave velocity structures determined from seismic experiments along the eastern flank of the Ruby Mountains metamorphic core complex, Nevada, show that the crust can be divided into three main layers corresponding to the upper, middle and lower crust. We interpreted crustal composition by integrating results of P-wave velocities ( Vp), S-wave velocities ( Vs), Poisson's ratios ( ?), seismic anisotropy, and reflection character with published geologic maps of the area. Near-surface estimates of Vp, Vs, ?, and anisotropy of 1.90-4.8 km/s, 1.01-2.75 km/s, 0.25-0.33, and 0.6-2.5%, respectively, are consistent with surface exposures of unconsolidated to consolidated sedimentary rocks, limestone, dolomite, siltstone, sandstone, porous sandstone, conglomerate, and weathered granite. Results from analysis of reflection responses, Vp, Vs, ?, and anisotropy also indicate that: (1) upper crustal rocks most likely consist of metaquartzite, schist, granite gneiss, and granite-granodiorite with Vp of 5.80-6.25 km/s, Vs of 3.20-3.72 km/s, ? of 0.22-0.25, and anisotropy of 0.6-2.5%; (2) possible middle crustal rocks are paragranulite, felsic granulite, felsic amphibolite gneiss, granite-granodiorite, and mica-quartz schist with Vp of 6.35-6.45 km/s, Vs of 3.70-3.75 km/s, and ? of 0.24; and (3) lower crustal rocks most likely consist of granulite- rather than amphibolite-facies rocks with Vp of 6.60-6.80 km/s, Vs of 3.85-3.92 km/s, ? of 0.24-0.25, and anisotropy of <3%. Our principal conclusions are: (1) significant addition of gabbroic rocks (underplating) is unlikely in the lower crust; (2) lower crustal rocks were stretched into sub-horizontal geometries with aligned minerals during extension, creating seismic lamellae in the lower crust; (3) present-day seismic velocities of highly extended core complex crust and normally extended Basin and Range crust are similar; and (4) orientations of fast shear waves near the surface and in the upper crust are sub-parallel to the regional maximum horizontal compressive stress in the Nevada part of the Basin and Range province.

  4. Detecting blind building façades from highly overlapping wide angle aerial imagery

    NASA Astrophysics Data System (ADS)

    Burochin, Jean-Pascal; Vallet, Bruno; Brédif, Mathieu; Mallet, Clément; Brosset, Thomas; Paparoditis, Nicolas

    2014-10-01

    This paper deals with the identification of blind building façades, i.e. façades which have no openings, in wide angle aerial images with a decimeter pixel size, acquired by nadir looking cameras. This blindness characterization is in general crucial for real estate estimation and has, at least in France, a particular importance on the evaluation of legal permission of constructing on a parcel due to local urban planning schemes. We assume that we have at our disposal an aerial survey with a relatively high stereo overlap along-track and across-track and a 3D city model of LoD 1, that can have been generated with the input images. The 3D model is textured with the aerial imagery by taking into account the 3D occlusions and by selecting for each façade the best available resolution texture seeing the whole façade. We then parse all 3D façades textures by looking for evidence of openings (windows or doors). This evidence is characterized by a comprehensive set of basic radiometric and geometrical features. The blindness prognostic is then elaborated through an (SVM) supervised classification. Despite the relatively low resolution of the images, we reach a classification accuracy of around 85% on decimeter resolution imagery with 60×40% stereo overlap. On the one hand, we show that the results are very sensitive to the texturing resampling process and to vegetation presence on façade textures. On the other hand, the most relevant features for our classification framework are related to texture uniformity and horizontal aspect and to the maximal contrast of the opening detections. We conclude that standard aerial imagery used to build 3D city models can also be exploited to some extent and at no additional cost for facade blindness characterisation.

  5. Utilizing the US Lab Nadir Research Window for Remote Sensing Operations with The Window Observational Research Facility (WORF)

    NASA Technical Reports Server (NTRS)

    Turner, Richard; Barley, Bryan; Gilbert, Paul A. (Technical Monitor)

    2002-01-01

    The Window Observational Research Facility (WORF) is an ISPR-based rack facility designed to take advantage of the high optical quality US Lab Nadir research window. The WORF is based on the ISS Expedite the Processing of Experiments to Space Station (EXPRESS) rack mechanical structure and electronic systems. The WORF has a unique payload volume located at the center of the rack that provides access to the window. The interior dimensions of the payload volume are 34-in. (86.36 cm) wide by 33-in. (83.82 cm) high by 23-in. (58.42 cm) deep. This facility supports the deployment of payloads such as 9 in. aerial photography cameras and 12 in. diameter optical equipment. The WORF coupled with the optical quality of the United States Lab window support the deployment of various payload disciplines. The WORF provides payloads with power, data command and control, air cooling, water cooling, and video processing. The WORF's payload mounting surfaces and interfaces include the interior payload mounting shelf and the interior and exterior aircraft-like seat tracks. The payload mounting shelf is limited to a maximum mass of 136 kg (299 pounds). The WORF can accommodate large payloads such as the commonly used Leica-Heerbrug RC-30 aerial photography camera (whose dimensions are 53.3 cm (21-in.) wide by 50.8 cm (20-in.) deep by 76.2 cm (30-in.) long). The performance characteristics of the WORF allow it to support an array of payload disciplines. The WORF provides a maximum of 3 Kw at 28 Vdc and has a maximum data rate of 10 Mbps. The WORF's unique payload volume is designed to be light-tight, down to 2.8 x 10(exp -11) Watts/cm2/steradian, and have low-reflective surfaces. This specially designed WORF interior supports payload investigations that observe low-light-level phenomenon such as aurora. Although the WORF rack does not employ any active rack isolation (i.e., vibration dampening) technology, the rack provides a very stable environment for payload operations (on the order of X microradians). The facility's software is capable of being updated during its period of deployment. The WORF project also includes a Suitcase Simulator to allow for a payload developer to verify data interfaces at his development site, a trainer rack for astronauts to learn how to operate the WORF prior to flight, and the use of the EXPRESS Functional Checkout Units to allow for payload checkout at the KSC prior to launch.

  6. Signature extension for sun angle, volume 1

    NASA Technical Reports Server (NTRS)

    Smith, J. A. (principal investigator); Berry, J. K.; Heimes, F.

    1975-01-01

    The author has identified the following significant results. Within a restricted zenith sun angle range of 35 - 50 degrees, it was empirically observed that canopy reflectance is mainly Lambertian. Reflectance changes with crop stage were simple shifts in scale in the sun angle range. It was noted that sun angle variations depend on canopy characteristics. Effects of the vegetative canopy were most pronounced at the larger solar zenith angles (20 %). The linear sun angle correction coefficients demonstrate a dependency on both crop stage (15-20 %) and crop type (10-20 %). The use of canopy reflectance modeling allowed for the generation of a simulated data set over an extremely broad envelope of sun angles.

  7. 'Magic Angle Precession'

    SciTech Connect

    Binder, Bernd [Quanics.com, Germany, 88679 Salem, P.O. Box 1247 (United States)], E-mail: binder@quanics.com

    2008-01-21

    An advanced and exact geometric description of nonlinear precession dynamics modeling very accurately natural and artificial couplings showing Lorentz symmetry is derived. In the linear description it is usually ignored that the geometric phase of relativistic motion couples back to the orbital motion providing for a non-linear recursive precession dynamics. The high coupling strength in the nonlinear case is found to be a gravitomagnetic charge proportional to the precession angle and angular velocity generated by geometric phases, which are induced by high-speed relativistic rotations and are relevant to propulsion technologies but also to basic interactions. In the quantum range some magic precession angles indicating strong coupling in a phase-locked chaotic system are identified, emerging from a discrete time dynamical system known as the cosine map showing bifurcations at special precession angles relevant to heavy nuclei stability. The 'Magic Angle Precession' (MAP) dynamics can be simulated and visualized by cones rolling in or on each other, where the apex and precession angles are indexed by spin, charge or precession quantum numbers, and corresponding magic angles. The most extreme relativistic warping and twisting effect is given by the Dirac spinor half spin constellation with 'Hyperdiamond' MAP, which resembles quark confinement.

  8. Near-Nadiral Normalized Radar Cross Section of the SEA Surface at Ku, Ka, and W-Bands: Comparison of Measurements and Models

    NASA Technical Reports Server (NTRS)

    Majurec, Ninoslav; Johnson, Joel T.; Tanelli, Simone; Durden, Stephen

    2012-01-01

    Understanding the relationship between wind speed and direction and the near-nadiral normalized radar cross section (NRCS) of the sea surface is important in many oceanographic and atmospheric remote sensing applications: (1) wind speed retrievals in traditional altimeter systems (2) assistance in calibration and path integrated attenuation processing for atmospheric profiling radars The desired wind speed (and direction in some cases) retrieval requires a clear understanding of the relationship between the relevant geophysical quantities and the observed NRCS Such understanding is available from existing electromagnetic models, but the presence of many such models, as well as implicit descriptions of the sea surface, motivates continued evaluation of model performance.

  9. Pitch Angle Survey of GOODS Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Boe, Benjamin; Kennefick, Daniel; Arkansas Galaxy Evolution Survey, Arkansas CenterSpace; Planetary Sciences

    2015-01-01

    This research looks at how the pitch angles of galaxies change over scales of cosmic time. We measure the pitch angle, or tightness of spiral winding, using a new code, Spirality. We then compare the results to those obtained from established software, 2DFFT (2 Dimensional Fast Fourier Transform). We investigate any correlation between pitch angle and redshift, or distance from Earth. Previous research indicates that the pitch angle of a galaxy correlates with its central bulge mass and the mass of its central black hole. Thus any evolution in the distribution of pitch angles could ultimately prove to be indicative of evolution in the supermassive black hole mass function. Galaxies from the Hubble GOODS (Great Observatories Origins Deep Survey) North and South were measured. We found that there was strong agreement between Spirality and 2DFFT measurements. Spirality measured the pitch angle of the GOODS galaxies with a lower error than 2DFFT on average. With both software a correlation between pitch angle and redshift was found. Spirality observed a 6.150 increase in pitch per unit redshift. The increase in pitch angle with redshift suggests that in the past galaxies had higher pitch angles, which could be indicative of lower central black hole masses (or, more directly, central bulge masses).

  10. Casting and Angling.

    ERIC Educational Resources Information Center

    Little, Mildred J.; Bunting, Camille

    The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

  11. Ring laser angle encoder

    NASA Technical Reports Server (NTRS)

    Coccoli, J. D.; Lawson, J. R.; Mc Garty, T. P.; Nickles, J. E.

    1969-01-01

    Ring laser angle encoder with a scanning photometer autocollimator and an isolation axis, provides continuous digital readout. It measures the angular difference in inertial attitudes of target /any phenomena generating or reflecting a light beam/ two at a time relative to target one at a time.

  12. Casting and Angling.

    ERIC Educational Resources Information Center

    Smith, Julian W.

    As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…

  13. Angle Sense: A Valuable Connector.

    ERIC Educational Resources Information Center

    Rubenstein, Rheta N.; And Others

    1993-01-01

    Proposes angle sense as a fundamental connector between mathematical concepts for middle grade students. Introduces the use of pattern blocks and a goniometer, a tool to measure angles, to help students develop angle sense. Discusses connections between angle measurement and the concepts of rational numbers, circles, area, number theory,…

  14. A Different Angle on Perspective

    ERIC Educational Resources Information Center

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  15. Skylab S-193 radar altimeter experiment analyses and results

    NASA Technical Reports Server (NTRS)

    Brown, G. S. (editor)

    1977-01-01

    The design of optimum filtering procedures for geoid recovery is discussed. Statistical error bounds are obtained for pointing angle estimates using average waveform data. A correlation of tracking loop bandwidth with magnitude of pointing error is established. The impact of ocean currents and precipitation on the received power are shown to be measurable effects. For large sea state conditions, measurements of sigma 0 deg indicate a distinct saturation level of about 8 dB. Near-nadir less than 15 deg values of sigma 0 deg are also presented and compared with theoretical models. Examination of Great Salt Lake Desert scattering data leads to rejection of a previously hypothesized specularly reflecting surface. Pulse-to-pulse correlation results are in agreement with quasi-monochromatic optics theoretical predictions and indicate a means for estimating direction of pointing error. Pulse compression techniques for and results of estimating significant waveheight from waveform data are presented and are also shown to be in good agreement with surface truth data. A number of results pertaining to system performance are presented.

  16. Perceptions of tilt angles of an agricultural tractor.

    PubMed

    Görücü, Serap; Cavallo, Eugenio; Murphy, Dennis

    2014-01-01

    A tractor stability simulator has been developed to help study tractor operators' perceptions of angles when the simulator is tilted to the side. The simulator is a trailer-mounted tractor cab equipped with hydraulic lift that can tilt the tractor cabin up to 30 degrees. This paper summarizes data from 82 participants who sat in the simulator while it was tilted. Demographic variables, estimates of tilt angles, and measured tilt angles were collected. The effects of age, gender, tractor driving experience, and frequency of operation on the estimated and measured tilt angles were analyzed. The results showed that about 50% of the participants reported estimations of side tilt angles within ±5 degrees of the actual angles, and nearly the same percentage overestimated the actual side tilt angles. Only a small percentage underestimated the angles. Older, more experienced, and male participants set higher limits on the actual angle at which they felt uncomfortable and would not drive. PMID:24417527

  17. Adjustable-angle pipe fitting

    SciTech Connect

    Kronberg, J.W.

    1991-01-01

    This invention pertains to a pipe fitting for joining two pipes at a desired, preselected angle and comprises a curved section of pipe with a generally circular cross-section. One end of the curved pipe is preferably furnished with a bell fitting. The other end is adapted to be inserted into the bell of another pipe fitting. The surface of the pipe is marked with circumferential lines spaced at several-degree intervals, the lines corresponding to the angle of the bend which will result if the pipe is cut along that line. The outer diameter of the pipe is closely controlled to be the same throughout its length as the outer diameter of a straight pipe, so the cut end can be inserted into the bell of another fitting without further treatment, and the radius of curvature of the pipe is larger than a standard street elbow, preferably three to ten times the diameter of the pipe. Thus, a cut approximately perpendicular to the axial centerline can be made at any point along the length of the pipe to form an elbow of any desired angle.

  18. Adjustable-angle pipe fitting

    SciTech Connect

    Kronberg, J.W.

    1991-12-31

    This invention pertains to a pipe fitting for joining two pipes at a desired, preselected angle and comprises a curved section of pipe with a generally circular cross-section. One end of the curved pipe is preferably furnished with a bell fitting. The other end is adapted to be inserted into the bell of another pipe fitting. The surface of the pipe is marked with circumferential lines spaced at several-degree intervals, the lines corresponding to the angle of the bend which will result if the pipe is cut along that line. The outer diameter of the pipe is closely controlled to be the same throughout its length as the outer diameter of a straight pipe, so the cut end can be inserted into the bell of another fitting without further treatment, and the radius of curvature of the pipe is larger than a standard street elbow, preferably three to ten times the diameter of the pipe. Thus, a cut approximately perpendicular to the axial centerline can be made at any point along the length of the pipe to form an elbow of any desired angle.

  19. Angling hydraulic jumps

    NASA Astrophysics Data System (ADS)

    Belmonte, Andrew; Thiffeault, Jean-Luc

    2008-11-01

    We present an experimental and mathematical study of the normal impact of a jet onto an inclined solid surface, focusing on the characteristics of the hydraulic jump. The angle of the surface is varied between vertical and horizontal positions, using both flat and curved (patterned) surfaces. Comparisons of the outer envelope of the hydraulic jump are made with the ballistic theory and the model of Edwards, Howison, Ockendon, & Ockendon.

  20. Laser angle sensor

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.

    1985-01-01

    A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures.

  1. MRI 'magic angle' imaging of finger tendons.

    PubMed

    Lambe, G; Coutts, G; McArthur, P; Dangerfield, P H

    2006-04-01

    The value of using the technique of magic angle MR imaging to demonstrate finger tendons is explored. Images of fresh frozen cadaveric specimens are presented and the structures that can be visualized in the finger are described. The results suggest that magic angle MR imaging may be a useful non-invasive technique of visualizing the details of the tendons and their surrounds in the hand. PMID:16182418

  2. Wide Angle Movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief movie illustrates the passage of the Moon through the Saturn-bound Cassini spacecraft's wide-angle camera field of view as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. From beginning to end of the sequence, 25 wide-angle images (with a spatial image scale of about 14 miles per pixel (about 23 kilometers)were taken over the course of 7 and 1/2 minutes through a series of narrow and broadband spectral filters and polarizers, ranging from the violet to the near-infrared regions of the spectrum, to calibrate the spectral response of the wide-angle camera. The exposure times range from 5 milliseconds to 1.5 seconds. Two of the exposures were smeared and have been discarded and replaced with nearby images to make a smooth movie sequence. All images were scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is approximately the same in every image. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS)at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  3. Shapes and Angles

    NSDL National Science Digital Library

    NASA

    2012-05-08

    In this activity (page 7 of PDF), learners will identify the general two-dimensional geometric shape of the uppermost cross section of an impact crater. They will also draw connections between the general two-dimensional geometric shape of an impact crater and the projectile's angle of impact. There are two versions of this activity: Challenge, where students construct a launcher and create their own craters; and Non-Challenge where students analyze pictures of craters. The Moon Math: Craters! guide follows a 5E approach, applying concepts of geometry, modeling, data analysis to the NASA lunar spacecraft mission, LCROSS.

  4. Wide angle reflections in OBC seismic physical model experiment

    NASA Astrophysics Data System (ADS)

    Yang, Zheng-Hua; Huang, Yi-Jian; Wu, Yong-Xin

    2012-06-01

    Wide angle acquisition has been taken as a significant measure to obtain high quality seismic data and is getting greater attention. In this paper, we discuss ocean bottom cable (OBC) seismic wide angle reflections on the basis of a layered model experiment. Some experiment results don't support theoretical conclusions. The main experimental conclusions are: 1. Wide angle reflection energies are stronger than non-wide-angle reflections (up to twice as strong) but there is a big difference between observations and theoretical calculations that suggest the wide angle reflection energies are 15 times the nonwide-angle reflection energy. The reflection energy increases gradually rather than sharply as the theoretical calculations suggest. 2. The reflection events remain hyperbolic when the offset increases. 3. Wide angle reflection dominant frequency is about 20-30% less than nonwide-angle reflections and decreases as the offset increases. The non-wide-angle reflection dominant frequency shows no obvious variation for small offsets. 4. There is no wave shape mutation or polarity reversal near the critical angle. 5. The reflection event group features are the same for both cases of incidence angle greater and less than the critical angle. 6. Direct arrivals, multiples, and water bottom refractions influence the wide angle reflections of the sea floor.

  5. Texture Components and Euler Angles

    E-print Network

    Rollett, Anthony D.

    1 Texture Components and Euler Angles 27-750 Texture, Microstructure components and their associated Euler angles. · The overall aim is to be able to describe a texture component by a single point (in orienta

  6. Evaluation of Terra and Aqua MODIS thermal emissive band response versus scan angle

    NASA Astrophysics Data System (ADS)

    Wenny, B. N.; Wu, A.; Madhavan, S.; Xiong, X.

    2014-10-01

    Terra and Aqua MODIS have operated near-continuously for over 14 and 12 years, respectively, and are key instruments for NASA's Earth Observing System. Observations from the 16 thermal emissive bands (TEB), covering wavelengths from 3.5 to 14.4 ?m with a nadir spatial resolution of 1 km are used to regularly generate a variety of atmosphere, ocean and land science products. The TEB detectors are calibrated using scan-by-scan observations of an on-board blackbody (BB). The current response versus scan angle (RVS) of the scan mirror was derived using a spacecraft deep-space pitch maneuver for Terra MODIS and characterized during prelaunch for Aqua MODIS. Earth view (EV) data over the complete range of angles of incidence (AOI) can be used to evaluate the on-orbit performance of the TEB RVS over the mission lifetime. Three approaches for tracking the TEB RVS on-orbit using EV observations are formulated. The first approach uses the multiple daily observations of Dome C BT at different AOI and their trend relative to coincident measurements from a ground temperature sensor. The second approach uses brightness temperatures (BT) retrieved over the cloud-free ocean to derive the trends at 13 AOI over the mission lifetime. The third approach tracks the dn response (normalized to the BB AOI) across the full swath width for Antarctic granules with the Dome C site at nadir. The viability of the three approaches is assessed and the long-term stability of the TEB RVS for both MODIS instruments is determined.

  7. Effects of Dipole Tilt Angle on Geomagnetic Activities

    NASA Astrophysics Data System (ADS)

    Nowada, M.; Shue, J.; Russell, C. T.

    2007-12-01

    Relationships between the clock angle of the interplanetary magnetic field (IMF) and each of the AL and AU indices are examined under various Earth's dipole tilt angles using the observational data for a period of 1978 to 1988. This study is performed by correlating the interplanetary magnetic field data obtained from the IMP 8 satellite, the AL and AU indices with the corrected seasonal variations, and the dipole tilt angle. It is found that for any value of the IMF clock angle, the values of AL and AU decrease when the dipole tilt angle becomes larger. It suggests that the geomagnetic activities strongly depend on the dipole tilt angle. Furthermore, our results are consistent with the semiannual variation of the geomagnetic activity and the predicted relationships between the geomagnetic activity, the IMF clock angle, and the dipole tilt angle, derived from the MHD simulation.

  8. Gonioscopy in primary angle closure glaucoma.

    PubMed

    Bruno, Christina A; Alward, Wallace L M

    2002-06-01

    Primary angle closure is a condition characterized by obstruction to aqueous humor outflow by the peripheral iris, and results in changes in the iridocorneal angle that are visible through gonioscopic examination. Gonioscopy in these eyes, however, can be difficult. This chapter discusses techniques that might help in the examination. These include beginning the examination with the inferior angle, methods to help in looking over the iris, cycloplegia, locating the corneal wedge, indentation, van Herick estimation, examining the other eye, and topical glycerin. Finally, there is a discussion about the pathology associated with the closed angle, with emphasis on the appearance of iris bombé, plateau iris, and the distinction between iris processes and peripheral anterior synechiae. PMID:15513458

  9. Triangles: Finding Interior Angle Measures

    NSDL National Science Digital Library

    2012-11-25

    In this lesson plan, students will start with a hands-on activity and then experiment with a GeoGebra-based computer model to investigate and discover the Triangle Angle Sum Theorem. Then they will use the Triangle Angle Sum Theorem to write and solve equations and find missing angle measures in a variety of examples.

  10. Ocular Biometry in Angle Closure

    PubMed Central

    Razeghinejad, Mohammad Reza; Banifatemi, Mohammad

    2013-01-01

    Purpose To compare ocular biometric parameters in primary angle closure suspects (PACS), primary angle closure glaucoma (PACG) and acute primary angle closure (APAC). Methods This cross-sectional study was performed on 113 patients including 33 cases of PACS, 45 patients with PACG and 35 subjects with APAC. Central corneal thickness (CCT), axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) were measured with an ultrasonic biometer. Lens-axial length factor (LAF), relative lens position, corrected ACD (CACD) and corrected lens position were calculated. The parameters were measured bilaterally but only data from the right eyes were compared. In the APAC group, biometric parameters were also compared between affected and unaffected fellow eyes. Logistic regression analysis was performed to identify risk factors. Results No statistically significant difference was observed in biometric parameters between PACS and PACG eyes, or between affected and fellow eyes in the APAC group (P>0.05 for all comparisons). However, eyes with APAC had thicker cornea (P=0.001), thicker lens (P<0.0001), shallower ACD (P=0.009), shallower CACD (P=0.003) and larger LAF (P<0.0001). Based on ROC curve analysis, lower ACD, and larger LT, LAF and CCT values were associated with APAC. In the APAC group, LAF (P<0.0001) and CCT (P=0.001) were significant risk factors. Conclusion This study revealed no significant difference in biometric characteristics in eyes with PACS and PACG. However, larger LAF and CCT were predictive of APAC. PMID:23825708

  11. {l_angle}110{r_angle} dendrite growth in aluminum feathery grains

    SciTech Connect

    Henry, S.; Rappaz, M. [Ecole Polytechnique Federale de Lausanne (Switzerland). Lab. de Metallurgie Physique; Jarry, P. [Pechiney Centre de Recherches de Voreppe (France)

    1998-11-01

    Automatic indexing of electron backscattered diffraction patterns, scanning electron microscopy, and optical microscopy observations have been carried out on aluminum-magnesium-silicon, aluminum-copper, and aluminum-silicon alloys directionally solidified or semicontinuously cast using the direct chill casting process. From these combined observations, it is shown that the feathery grains are made of {l_angle}110{r_angle} primary dendrite trunks (e.g., [011{bar 1}]) split in their centers by a coherent (111) twin plane. The average spacing of the dendrite trunks in the twin plane (about 10 to 20 {micro}m) is typically one order of magnitude smaller than that separating successive rows of trunks (or twin planes). The [011{bar 1}] orientation of these trunks is close to the thermal gradient direction (typically within 15 deg)--a feature probably resulting from a growth competition mechanism similar to that occurring during normal <100> columnar dendrite growth. On both sides of these trunks, secondary dendrite arms also grow along {l_angle}110{r_angle} directions. Their impingement creates wavy noncoherent twin boundaries between the coherent twin planes. In the twin plane, evidence is shown that {l_angle}110{r_angle} branching mechanisms lead to the propagation of the twinned regions, to the regular arrangement of the primary dendrite trunks along a [{bar 2}11] direction, and to coherent planar twin boundaries. From these observations, it is concluded that the feathery grains are probably the result of a change from a normal <100> to a {l_angle}110{r_angle} surface tension/attachment kinetics anisotropy growth mode. Finally, the proposed mechanisms of leathery grain growth are further supported by the observation of {l_angle}110{r_angle} dendrite growth morphologies in thin aluminum-zinc coatings.

  12. Equilibrium contact angle or the most-stable contact angle?

    PubMed

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

    2014-04-01

    It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation. PMID:24140073

  13. Methane Cross-Validation Between Spaceborne Solar Occultation Observations from ACE-FTS, Spaceborne Nadir Sounding from Gosat, and Ground-Based Solar Absorption Measurements, at a High Arctic Site.

    NASA Astrophysics Data System (ADS)

    Holl, G.; Walker, K. A.; Conway, S. A.; Saitoh, N.; Boone, C. D.; Strong, K.; Drummond, J. R.

    2014-12-01

    We present cross-validation of remote sensing observations of methane profiles in the Canadian High Arctic. Methane is the third most important greenhouse gas on Earth, and second only to carbon dioxide in its contribution to anthropogenic global warming. Accurate and precise observations of methane are essential to understand quantitatively its role in the climate system and in global change. The Arctic is a particular region of concern, as melting permafrost and disappearing sea ice might lead to accelerated release of methane into the atmosphere. Global observations require spaceborne instruments, in particular in the Arctic, where surface measurements are sparse and expensive to perform. Satellite-based remote sensing is an underconstrained problem, and specific validation under Arctic circumstances is required. Here, we show a cross-validation between two spaceborne instruments and ground-based measurements, all Fourier Transform Spectrometers (FTS). We consider the Canadian SCISAT ACE-FTS, a solar occultation spectrometer operating since 2004, and the Japanese GOSAT TANSO-FTS, a nadir-pointing FTS operating at solar and terrestrial infrared wavelengths, since 2009. The ground-based instrument is a Bruker Fourier Transform Infrared (FTIR) spectrometer, measuring mid-infrared solar absorption spectra at the Polar Environmental and Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut (80°N, 86°W) since 2006. Measurements are collocated considering temporal, spatial, and geophysical criteria and regridded to a common vertical grid. We perform smoothing on the higher-resolution instrument results to account for different vertical resolutions. Then, profiles of differences for each pair of instruments are examined. Any bias between instruments, or any accuracy that is worse than expected, needs to be understood prior to using the data. The results of the study will serve as a guideline on how to use the vertically resolved methane products from ACE and GOSAT within the High Arctic region.

  14. Angle Kappa and its importance in refractive surgery

    PubMed Central

    Moshirfar, Majid; Hoggan, Ryan N.; Muthappan, Valliammai

    2013-01-01

    Angle kappa is the difference between the pupillary and visual axis. This measurement is of paramount consideration in refractive surgery, as proper centration is required for optimal results. Angle kappa may contribute to MFIOL decentration and its resultant photic phenomena. Adjusting placement of MFIOLs for angle kappa is not supported by the literature but is likely to help reduce glare and haloes. Centering LASIK in angle kappa patients over the corneal light reflex is safe, efficacious, and recommended. Centering in-between the corneal reflex and the entrance pupil is also safe and efficacious. The literature regarding PRK in patients with an angle kappa is sparse but centering on the corneal reflex is assumed to be similar to centering LASIK on the corneal reflex. Thus, centration of MFIOLs, LASIK, and PRK should be focused on the corneal reflex for patients with a large angle kappa. More research is needed to guide surgeons’ approach to angle kappa. PMID:24379548

  15. Narrow Angle movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief three-frame movie of the Moon was made from three Cassini narrow-angle images as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. The purpose of this particular set of images was to calibrate the spectral response of the narrow-angle camera and to test its 'on-chip summing mode' data compression technique in flight. From left to right, they show the Moon in the green, blue and ultraviolet regions of the spectrum in 40, 60 and 80 millisecond exposures, respectively. All three images have been scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is the same in each image. The spatial scale in the blue and ultraviolet images is 1.4 miles per pixel (2.3 kilometers). The original scale in the green image (which was captured in the usual manner and then reduced in size by 2x2 pixel summing within the camera system) was 2.8 miles per pixel (4.6 kilometers). It has been enlarged for display to the same scale as the other two. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS) at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  16. Solar cell angle of incidence corrections

    SciTech Connect

    Burger, D.R.; Mueller, R.L.

    1995-10-01

    Literature on solar array angle of incidence corrections was found to be sparse and contained no tabular data for support. This lack along with recent data on 27 GaAs/Ge 4 cm by 4 cm cells initiated the analysis presented in this paper. The literature cites seven possible contributors to angle of incidence effects: cosine, optical front surface, edge, shadowing, UV degradation, particulate soiling, and background color. Only the first three are covered in this paper due to lack of sufficient data. The cosine correction is commonly used but is not sufficient when the incident angle is large. Fresnel reflection calculations require knowledge of the index of refraction of the coverglass front surface. The absolute index of refraction for the coverglass front surface was not known nor was it measured due to lack of funds. However, a value for the index of refraction was obtained by examining how the prediction errors varied with different assumed indices and selecting the best fit to the set of measured values. Corrections using front surface Fresnel reflection along with the cosine correction give very good predictive results when compared to measured data, except there is a definite trend away from predicted values at the larger incident angles. This trend could be related to edge effects and is illustrated by a use of a box plot of the errors and by plotting the deviation of the mean against incidence angle. The trend is for larger deviations at larger incidence angles and there may be a fourth order effect involved in the trend. A chi-squared test was used to determine if the measurement errors were normally distributed. At 10 degrees the chi-squared test failed, probably due to the very small numbers involved or a bias from the measurement procedure. All other angles showed a good fit to the normal distribution with increasing goodness-of-fit as the angles increased which reinforces the very small numbers hypothesis.

  17. 8.G Find the Angle

    NSDL National Science Digital Library

    2012-05-01

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: In triangle $\\Delta ABC$, point $M$ is the point of intersection of the bisectors of angles $\\angle BAC$, $\\angle ABC$, and $\\angle ACB$. The measure o...

  18. The Critical Angle Can Override the Brewster Angle

    ERIC Educational Resources Information Center

    Froehle, Peter H.

    2009-01-01

    As a culminating activity in their study of optics, my students investigate polarized light and the Brewster angle. In this exercise they encounter a situation in which it is impossible to measure the Brewster angle for light reflecting from a particular surface. This paper describes the activity and explains the students' observations.

  19. On the role of visible radiation in ozone profile retrieval from nadir UV/VIS satellite measurements: An experiment with neural network algorithms inverting SCIAMACHY data

    NASA Astrophysics Data System (ADS)

    Sellitto, P.; Di Noia, A.; Del Frate, F.; Burini, A.; Casadio, S.; Solimini, D.

    2012-08-01

    Theoretical evidence has been given on the role of visible (VIS) radiation in enhancing the accuracy of ozone retrievals from satellite data, especially in the troposphere. However, at present, VIS is not being systematically used together with ultraviolet (UV) measurements, even when possible with one single instrument, e.g., the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY). Reasons mainly reside in the defective performance of optimal estimation and regularization algorithms caused by inaccurate modeling of VIS interaction with aerosols or clouds, as well as in inconsistent intercalibration between UV and VIS measurements. Here we intend to discuss the role of VIS radiation when it feeds a retrieval algorithm based on Neural Networks (NNs) that does not need a forward radiative transfer model and is robust with respect to calibration errors. The NN we designed was trained with a set of ozonesondes (OSs) data and tested over an independent set of OS measurements. We compared the ozone concentration profiles retrieved from UV-only with those retrieved from UV plus VIS nadir data taken by SCIAMACHY. We found that VIS radiation was able to yield more than 10% increase of accuracy and to substantially reduce biases of retrieved profiles at tropospheric levels.

  20. What we Hope to Learn about Global Mineral Dust Aerosols from EOS Multi-Angle Imaging SpectroRadiometer (MISR)

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph

    2000-01-01

    On global scales, just a few broad atmospheric aerosol compositional groups are commonly observed. Of these, "mineral dust" is the only group which both contains non-spherical particles, and typically has size distributions with enough large particles for particle shape to affect its visible-light-scattering properties. The MISR instrument is scheduled for launch into a 10:30 AM sun-synchronous, polar orbit aboard the EOS Terra satellite in 1999. MISR will measure the upwelling visible radiance from Earth in 4 spectral bands centered at 446, 558, 672, and 866 nm, at each of 9 emission angles spread out in the forward and aft directions along the flight path at +/-70.5 deg, +/-60.0 deg, +/-45.6 deg, +/-26.1deg, and nadir. Over a period of 7 minutes, as the spacecraft flies along, a 360 km wide swath of Earth will successively be viewed by each of the cameras, allowing MISR to sample a very large range of scattering angles; in mid latitudes, the instrument will observe scattering angles between about 60 deg and 160 deg. Global coverage will be acquired about once in 9 days at the equator; the nominal mission lifetime is 6 years. The distinction in single scattering phase function between natural distributions of spherical and randomly oriented, non-spherical particles, with a broad range of aspect ratios, shows up strongly for scattering angles ranging from about 90 deg to near 180 deg. For non-spherical particle distributions, single scattering phase functions tend to be much flatter in this region than for spherical particles. Since MISR samples the relevant range of scattering angles very well, we expect to be able to make critical distinctions between natural distributions of spherical and randomly oriented, non-spherical particles with MISR data. We anticipate that the new multiangle, multispectral data from MISR will also contain other information about particle properties, a major step beyond current spacecraft remote sensing retrievals, which obtain aerosol optical depth based on entirely assumed particle microphysical properties. According to simulations over cloud-free, calm ocean, for pure particles with natural ranges of optical depth, particle size, and indices of refraction, MISR should retrieve column optical depth for all but the darkest particles, to an uncertainty of at most 0.05 or 20%, whichever is larger, even if the particle properties are poorly known. For one common particle type, soot, constraints on the optical depth over dark ocean are very poor. The simulated measurements also should allow us to separate two to four compositional groups based on indices of refraction, and to identify three to four distinct size groups between 0.1 and 2.0 microns characteristic radius at most latitudes. The technique is most sensitive to particle microphysical properties in the "accumulation mode" sizes. where particle scattering undergoes the transition from Rayleigh to large-particle regimes for the MISR wavelengths. Based on these results, we expect to distinguish air masses containing different aerosol types, routinely and globally, with multiangle remote sensing data. Such data complements in situ and field data, which can provide details about aerosol size and composition locally that are needed to assess the radiative effects of aerosols quantitatively. Both field data and correlations in space and time with likely source and sink regions will also be helpful in developing a global picture of mineral dust aerosol budgets. Further work on the expected sensitivity of MISR to natural mixtures of pure particles, including climatologically likely mineral dust components, is currently underway.

  1. Magic-Angle Gradient-Coil Design

    Microsoft Academic Search

    R. Bowtell; A. Peters

    1995-01-01

    The target-field approach to gradient-coil design has been applied to the production of coils which will produce a linear gradient in the z component of the magnetic field, in a direction oriented at the magic angle to the z axis. The resulting coils, which consist of wires wound on the surface of a cylinder whose axis is parallel to the

  2. Solar elevation angle probability distribution

    Microsoft Academic Search

    D. C. Larson; C. R. Acquista

    1980-01-01

    The probability distribution of solar elevation angles is determined, and the importance of this distribution on concentrator design is discussed. It is concluded that the time probability function for the solar elevation angle is important when considering alternative low-concentration systems for year-round or seasonal applications.

  3. Measuring Angles in Physical Therapy.

    ERIC Educational Resources Information Center

    Greeley, Nansee; Offerman, Theresa Reardon

    1997-01-01

    Features articles about physical therapy and its history as related to geometry through measurement of body angles. Includes open-ended worksheets for mathematics activities that introduce students to angle measurement, data analysis, and mathematical tools. Activities include: (1) Making Your Own Goniometer; (2) Range of Motion; (3) Active versus…

  4. Unitarity Triangle Angle Measurements at BaBar

    SciTech Connect

    Latham, Thomas E.; /SLAC

    2005-06-30

    We present recent results of measurements of the Unitarity Triangle angles alpha, beta and gamma made with the BaBar detector at the PEP-II asymmetric B factory. We present recent results of measurements of the Unitarity Triangle angles alpha, beta and gamma made with the BaBar detector at the PEP-II asymmetric B factory.

  5. Supercritical angle fluorescence (SAF) microscopy.

    PubMed

    Ruckstuhl, Thomas; Verdes, Dorinel

    2004-09-01

    We explore a new confocal microscope for the detection of surface-generated fluorescence. The instrument is designed for high resolution imaging as well as for the readout of large biochips. Special feature is the separated collection of two different fluorescence emission modes. One optical path covers the emission into the glass at low surface angles, the other captures high angles, exceeding the critical angle of the water/glass interface. Due to the collection of the supercritical angle fluorescence (SAF) the confocal detection volume is strictly confined to the interface, whereas the low angles collect much deeper from the aqueous analyte solution. Hence the system can deliver information about surfacebound and unbound fraction of fluorescent analyte simultaneously. PMID:19483970

  6. Shear angle of magnetic fields.

    NASA Astrophysics Data System (ADS)

    Yanping, Lü; Wang, Jingxiu; Wang, Huaning

    1993-11-01

    The authors introduce a new parameter, the shear angle of vector magnetic fields, ??, to describe the non-potentiality of magnetic fields in active regions, which is defined as the angle between the observed vector magnetic field and its corresponding current-free field. In the case of highly inclined field configurations, this angle is approximately equal to the "angular shear", ??, defined by Hagyard et al. (1984). ?? can be considered as the projection of the shear angle, ??, on the photosphere. For the active region studied, the shear angle, ??, seems to have a better and neater correspondence with flare activity than does ??. It gives a clearer explanation of the non-potentiality of magnetic fields. It is a better measure of the deviation of the observed magnetic field from a potential field, and is directly related to the magnetic free energy stored in non-potential fields.

  7. Spinning angle optical calibration apparatus

    DOEpatents

    Beer, Stephen K. (Morgantown, WV); Pratt, II, Harold R. (Morgantown, WV)

    1991-01-01

    An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

  8. Particle friction angles in steep mountain channels

    NASA Astrophysics Data System (ADS)

    Prancevic, Jeff P.; Lamb, Michael P.

    2015-02-01

    Sediment transport rates in steep mountain channels are typically an order of magnitude lower than predicted by models developed for lowland rivers. One hypothesis for this observation is that particles are more stable in mountain channels due to particle-particle interlocking or bridging across the channel width. This hypothesis has yet to be tested, however, because we lack direct measurements of particle friction angles in steep mountain channels. Here we address this data gap by directly measuring the minimum force required to dislodge sediment (pebbles to boulders) and the sediment weight in mountain channels using a handheld force gauge. At eight sites in California, with reach-averaged bed angles ranging from 0.5° to 23° and channel widths ranging from 2 m to 16 m, we show that friction angles in natural streams average 68° and are 16° larger than those typically measured in laboratory experiments, which is likely due to particle interlocking and burial. Results also show that larger grains are disproportionately more stable than predicted by existing models and that grains organized into steps are twice as stable as grains outside of steps. However, the mean particle friction angle does not vary systematically with bed slope. These results do not support systematic increases in friction angle in steeper and narrower channels to explain the observed low sediment transport rates in mountain channels. Instead, the spatial pattern and grain-size dependence of particle friction angles may indirectly lower transport rates in steep, narrow channels by stabilizing large clasts and channel-spanning steps, which act as momentum sinks due to form drag.

  9. Estimation of stratospheric NO2 from nadir-viewing satellites: The MPI-C TROPOMI verification algorithm

    NASA Astrophysics Data System (ADS)

    Beirle, Steffen; Wagner, Thomas

    2015-04-01

    The retrieval of tropospheric column densities of NO2 requires the subtraction of the stratospheric fraction from the total columns derived by DOAS. Here we present a modified reference sector method, which estimates the stratosphere over "clean" regions, as well as over clouded scenarios in which the tropospheric column is shielded. The selection of "clean" pixels is realized gradually by assingning weighting factors to the individual ground pixels, instead of applying binary flags. Global stratospheric fields are then compiled by "weighted convolution". In a second iteration, unphysical negative tropospheric residues are suppressed by adjusting the weights respectively. This algorithm is foreseen as "verification algorithm" for the upcoming TROPOMI on S5p. We show the resulting stratospheric estimates and tropospheric residues for a test data set based on OMI observations. The dependencies on the a-priori settings (definition of weighting factors and convolution kernels) are discussed, and the results are compared to other products, in particular to DOMINO v.2 (based on assimilation, similar to the TROPOMI prototype algorithm) and the NASA standard product (based on a similar reference-region-type approach).

  10. Lowest ever CD4 lymphocyte count (CD4 nadir) as a predictor of current cognitive and neurological status in human immunodeficiency virus type 1 infection—The Hawaii Aging with HIV Cohort

    Microsoft Academic Search

    Victor Valcour; Priscilla Yee; Andrew E. Williams; Bruce Shiramizu; Michael Watters; Ola Selnes; Robert Paul; Cecilia Shikuma; Ned Sacktor

    2006-01-01

    Low CD4 lymphocyte count was a marker for neurological disease in human immunodeficiency virus type 1 (HIV-1); but is now\\u000a less common among patients with access to highly active antiretroviral therapy. In this study, the authors determine the reliability\\u000a of self-reported CD4 nadir and its predictive value for neurological status. The authors identify a high degree of reliability\\u000a (r =

  11. Enhanced sensitivity growth hormone (GH) chemiluminescence assay reveals lower postglucose nadir GH concentrations in men than women

    Microsoft Academic Search

    I. M. Chapman; M. L. Hartman; M. Straume; M. L. Johnson; J. D. Veldhuisups

    1994-01-01

    ABSTRACT Modifications,were,made,to a commercially,available,human,(h) GH chemiluminescence assay (Nichols Luma Tag hGH assay), which im- proved,its sensitivity,to,0.002 fig\\/L. The,results,of,this,assay,had,a high,correlation,with,those,of,the,Nichols,hGH,immunoradiometric assay,(IRMA; r = 0.91; P < 0.001). The,addition,of recombinant,hGH- binding,protein,(0.1-10 nmol\\/L),to,standards,and,serum,samples caused,a dose-responsive,reduction,in measured,GH in both,the,chemi- luminescence,assay,and,the,IRMA; at physiological,concentrations,of hGH-binding protein, a lo-20% reduction was observed. Fifteen nor- mal,young,adults,(nine,men,and,six,women),underwent,a standard 100-g oral glucose tolerance test, and plasma GH was measured from

  12. Positron Emission Mammography with Multiple Angle Acquisition

    SciTech Connect

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FbG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three-dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  13. LINTRAN v2.0: A linearised vector radiative transfer model for efficient simulation of satellite-born nadir-viewing reflection measurements of cloudy atmospheres

    NASA Astrophysics Data System (ADS)

    Schepers, D.; aan de Brugh, J. M. J.; Hahne, Ph.; Butz, A.; Hasekamp, O. P.; Landgraf, J.

    2014-12-01

    Radiance measurements of solar radiation that is backscattered by the Earth?s atmosphere or surface contain information about the atmospheric composition and the state of the Earth?s surface. Retrieving such information from satellite-based observations in nadir geometry employs a radiative transfer forward model. The forward model simulates the observed quantity, aiming to reproduce the observation. LINTRAN v2.0 is a linearised vector radiative transfer forward model, employing forward-adjoint theory, that is capable of modelling cloud contaminated satellite observations and their derivatives with respect to the state of the atmosphere and the Earth?s surface in a numerically efficient manner. A significant gain in efficiency with respect to its predecessor (LINTRAN v1.0) is achieved through a mathematical framework that combines an approximate iterative solving method using the forward-adjoint perturbation theory with separation of the first N orders of scattering from the diffuse intensity vector field. Contributions to the observable up to order of scattering N are recursively solved in an analytical manner. Contributions from higher orders of scattering are subsequently solved in a numerical manner, assuming that the intensity field varies linearly with the vertical coordinate within an optically homogeneous model layer. This method is implemented in LINTRAN v2.0, choosing N=2, within the general framework of forward-adjoint perturbation theory. This new approach allows us to decrease the number of model layers and the degree of angular quadrature within the numerical solver by a factor of 10 and 1.4 respectively, compared to the previous model version, assuming a homogeneous atmosphere loaded with scattering Mie particles (size parameter ??35). In this homogeneous atmosphere, the reduced discretisation sampling in turn reduces the numerical effort associated with the numerical matrix solver by a factor of 42 relative to the previous model version, without a loss in model accuracy.

  14. Compression failure of angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Peel, Larry D.; Hyer, Michael W.; Shuart, Mark J.

    1991-01-01

    The present work deals with modes and mechanisms of failure in compression of angle-ply laminates. Experimental results were obtained from 42 angle-ply IM7/8551-7a specimens with a lay-up of ((plus or minus theta)/(plus or minus theta)) sub 6s where theta, the off-axis angle, ranged from 0 degrees to 90 degrees. The results showed four failure modes, these modes being a function of off-axis angle. Failure modes include fiber compression, inplane transverse tension, inplane shear, and inplane transverse compression. Excessive interlaminar shear strain was also considered as an important mode of failure. At low off-axis angles, experimentally observed values were considerably lower than published strengths. It was determined that laminate imperfections in the form of layer waviness could be a major factor in reducing compression strength. Previously developed linear buckling and geometrically nonlinear theories were used, with modifications and enhancements, to examine the influence of layer waviness on compression response. The wavy layer is described by a wave amplitude and a wave length. Linear elastic stress-strain response is assumed. The geometrically nonlinear theory, in conjunction with the maximum stress failure criterion, was used to predict compression failure and failure modes for the angle-ply laminates. A range of wave length and amplitudes were used. It was found that for 0 less than or equal to theta less than or equal to 15 degrees failure was most likely due to fiber compression. For 15 degrees less than theta less than or equal to 35 degrees, failure was most likely due to inplane transverse tension. For 35 degrees less than theta less than or equal to 70 degrees, failure was most likely due to inplane shear. For theta less than 70 degrees, failure was most likely due to inplane transverse compression. The fiber compression and transverse tension failure modes depended more heavily on wave length than on wave amplitude. Thus using a single parameter, such as a ratio of wave amplitude to wave length, to describe waviness in a laminate would be inaccurate. Throughout, results for AS4/3502, studied previously, are included for comparison. At low off-axis angles, the AS4/3502 material system was found to be less sensitive to layer waviness than IM7/8551-7a. Analytical predictions were also obtained for laminates with waviness in only some of the layers. For this type of waviness, laminate compression strength could also be considered a function of which layers in the laminate were wavy, and where those wavy layers were. Overall, the geometrically nonlinear model correlates well with experimental results.

  15. Robust Delaunay triangulation for domain with acute angles

    NASA Astrophysics Data System (ADS)

    Meng, Xianhai; Mei, Guoyi

    2013-07-01

    A new algorithm is presented to automatic generate conforming Delaunay triangulation of non-manifold geometric domains with acute angles. The algorithm is based on Delaunay refinement technique, which often failed to terminate when there are small angles in input geometry. By assigning proper weights to vertices on sharp-angled elements and take place Delaunay triangulation with weighted Delaunay triangulation, the algorithm can accept any inputs without any bound on angle and without setting any protected area and adding any new vertices near the sharp-angled elements. The algorithm also guarantees bounded circumradius to shortest edge length for all elements except the ones near small input angles. A simple terminator proof and some results are also presented.

  16. Image processing-based wheel steer angle detection

    NASA Astrophysics Data System (ADS)

    Shu, Tian; Zheng, Yongan; Shi, Zhongke

    2013-10-01

    Wheel steer angle information is crucial for the estimation of vehicle sideslip. Different from previous detection methods using angle sensors, this work presents a new wheel steer angle detection method based on a computer vision system providing image sequences recorded by a camera mounted on a car. The difference between wheel steering right and left is analyzed to determine steer direction while wheel steer angle in the image is derived from the information of the wheel contour extracted by the threshold segmentation and edge extraction. Experimental results show the efficiency of the proposed approach.

  17. Minimum uncertainty measurements of angle and angular momentum

    E-print Network

    Z. Hradil; J. Rehacek; Z. Bouchal; R. Celechovsky; L. L. Sanchez-Soto

    2006-05-16

    The uncertainty relations for angle and angular momentum are revisited. We use the exponential of the angle instead of the angle itself and adopt dispersion as a natural measure of resolution. We find states that minimize the uncertainty product under the constraint of a given uncertainty in angle or in angular momentum. These states are described in terms of Mathieu wave functions and may be approximated by a von Mises distribution, which is the closest analogous of the Gaussian on the unit circle. We report experimental results using beam optics that confirm our predictions.

  18. Solar Angles and Tracking Systems

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students learn about the daily and annual cycles of solar angles used in power calculations to maximize photovoltaic power generation. They gain an overview of solar tracking systems that improve PV panel efficiency by following the sun through the sky.

  19. Compact Right-Angle Connector

    NASA Technical Reports Server (NTRS)

    Barajas, Salvador L.; Pierson, Vonde E.

    1989-01-01

    New right-angle connector between hose and "quick-disconnect" coupler smaller and simpler than its predecessor. Employs fewer parts and therefore cheaper and less likely to leak. Connector consists of only two major parts.

  20. Two Comments on Bond Angles

    NASA Astrophysics Data System (ADS)

    Glaister, P.

    1997-09-01

    Tetrahedral Bond Angle from Elementary Trigonometry The alternative approach of using the scalar (or dot) product of vectors enables the determination of the bond angle in a tetrahedral molecule in a simple way. There is, of course, an even more straightforward derivation suitable for students who are unfamiliar with vectors, or products thereof, but who do know some elementary trigonometry. The starting point is the figure showing triangle OAB. The point O is the center of a cube, and A and B are at opposite corners of a face of that cube in which fits a regular tetrahedron. The required bond angle alpha = AÔB; and using Pythagoras' theorem, AB = 2(square root 2) is the diagonal of a face of the cube. Hence from right-angled triangle OEB, tan(alpha/2) = (square root 2) and therefore alpha = 2tan-1(square root 2) is approx. 109° 28' (see Fig. 1).

  1. Current Status of Cloud Masks for the Multi-angle Imaging SpectroRadiometer

    NASA Astrophysics Data System (ADS)

    Wilson, M. J.; Zhao, G.; Yang, Y.; Chapman, B.; di Girolamo, L.

    2004-05-01

    The Multi-angle Imaging SpectroRadiometer (MISR) on-board EOS-Terra makes observations at 9 angles (1 nadir, 8 oblique) in the visible and near-infrared. Cloud detection is a critical part of the MISR mission, but is made more complicated by the fact that there are no spectral channels longward of 866 nm in wavelength. This has led to the development of several novel approaches to cloud detection. For MISR, three independent cloud masks have been developed: the Radiometric Camera-by-camera Cloud Mask (RCCM), the Stereoscopically-Derived Cloud Mask (SDCM), and the Angular Signature Cloud Mask (ASCM). This poster will demonstrate the current status of the three MISR cloud masks and the strengths and weaknesses inherent in each. Methods of evaluating the cloud masks will also be shown, including visible inspection and comparisons with the Moderate Resolution Imaging Spectroradiometer (MODIS). Finally, analyses of the minimum detectable optical depths will be demonstrated, through the use of ground based data.

  2. Angles of multivariable root loci

    NASA Technical Reports Server (NTRS)

    Thompson, P. M.; Stein, G.; Laub, A. J.

    1982-01-01

    A generalized eigenvalue problem is demonstrated to be useful for computing the multivariable root locus, particularly when obtaining the arrival angles to finite transmission zeros. The multivariable root loci are found for a linear, time-invariant output feedback problem. The problem is then employed to compute a closed-loop eigenstructure. The method of computing angles on the root locus is demonstrated, and the method is extended to a multivariable optimal root locus.

  3. Measurements of Neutrino Oscillation Angle ?13

    NASA Astrophysics Data System (ADS)

    Kuze, Masahiro

    Neutrinos exhibit an interesting phenomenon called "neutrino oscillation", in which a neutrino changes its flavor after traveling some flight length. Many experiments measured the mixing angles and mass differences, but the angle ?13 had been unmeasured due to its smallness compared to others. During 2011 and 2012, series of new-generation neutrino experiments reported positive results in ?13 search, and its value has been determined to be just below the previous upper limit. The non-zero result of ?13 is a very good news for future of neutrino physics, since it opens a possibility of measuring the CP violation phase in the lepton sector. An introduction to neutrino oscillation and latest experimental results are presented. A detail is put on Double Chooz reactor experiment, in which the author is involved.

  4. Nonlinear H? robust control for satellite large angle attitude maneuvers

    Microsoft Academic Search

    Long-life Show; Jyh-Ching Juang; Ciann-Dong Yang

    2001-01-01

    The paper presents a nonlinear H? state feedback for large angle attitude control of satellite. The dynamic equations of satellite with full-coupled body fixed canted attitude thruster control are derived. A nonlinear H? controller is designed to achieve stability and disturbance rejection for large angle maneuvers. The simulation results based on spacecraft system are presented to demonstrate the effectiveness of

  5. Gyroscopic testing of accelerometers to determine coning angle

    NASA Astrophysics Data System (ADS)

    Mishra, Nina; Harrison, Jonathan A.; Hepner, David J.

    1988-11-01

    An experiment was performed to determine how accurately accelerometers could measure the coning angle of a spinning and coning laboratory gyroscope. Tests showed that coning angle measurements were well within expected results. The accelerometer can be used with or in place of the yawsonde for determination of flight stability of spin-stabilized projectiles.

  6. Moment-angle manifolds and complexes. Lecture notes KAIST'2010

    Microsoft Academic Search

    Taras Panov

    2010-01-01

    These are notes of the lectures given during the Toric Topology Workshop at the Korea Advanced Institute of Science and Technology in February 2010. We describe several approaches to moment-angle manifolds and complexes, including the intersections of quadrics, complements of subspace arrangements and level sets of moment maps. We overview the known results on the topology of moment-angle complexes, including

  7. Peripapillary Schisis in Glaucoma Patients With Narrow Angles and

    E-print Network

    Srinivasan, Vivek J.

    Peripapillary Schisis in Glaucoma Patients With Narrow Angles and Increased Intraocular Pressure cases of peripapillary retinal schisis in patients with glaucoma without evidence of optic nerve pits patient was followed over time. RESULTS: The first patient, diagnosed with narrow angle glaucoma

  8. Direction angle sensitivity of agricultural field backscatter with AIRSAR data

    NASA Technical Reports Server (NTRS)

    Dubois, Pascale C.; Rignot, Eric; Vanzyl, Jakob J.

    1993-01-01

    This paper presents a study of the direction angle sensitivity of radar backscatter from agricultural fields. The direction angle is defined as the angle between the incident plane and the perpendicular to the field row direction. Previous studies have concentrated on comparing the backscatter of agricultural fields imaged with 0, 45, and 90 degree direction angles. In contrast, this study concentrates on the backscatter changes occurring when the direction angle is modified by a few degrees or even by fractions of a degree. This is possible by using the output of the NASA/JPL AIRSAR processor, in which sixteen independent frames are formed, each one corresponding to the same radar scene imaged with a slightly different squint angle. The studied data set is an agricultural area in La Mancha, Spain acquired in June and July 1991 during the EFEDA experiment. This paper describes the observed backscatter variations of the agricultural fields with direction angle measured at P, L, and C bands. As expected, the backscatter is maximum for a 0 degree direction angle. For several fields, the backscatter at P and L bands drops by more than 10 dB for a 5 degree change in direction angle. Furthermore, the sensitivity to the direction angle decreases with increasing vegetation. The variations in backscatter are compared with model predictions. One model, which agrees with scatterometer data, underestimates the observed backscatter variations with direction angle by more than 10 dB. It does not take into account the possible coherent component of the radar signal. We believe the strong direction sensitivity of agricultural field backscatter obtained with SAR data is due to a Bragg resonant effect, resulting in a strong coherent return when the direction angle is zero. The observations are then projected to the case of spaceborne SAR data.

  9. Contact-angle hysteresis on super-hydrophobic surfaces.

    PubMed

    McHale, G; Shirtcliffe, N J; Newton, M I

    2004-11-01

    The relationship between perturbations to contact angles on a rough or textured surface and the super-hydrophobic enhancement of the equilibrium contact angle is discussed theoretically. Two models are considered. In the first (Wenzel) case, the super-hydrophobic surface has a very high contact angle and the droplet completely contacts the surface upon which it rests. In the second (Cassie-Baxter) case, the super-hydrophobic surface has a very high contact angle, but the droplet bridges across surface protrusions. The theoretical treatment emphasizes the concept of contact-angle amplification or attenuation and distinguishes between the increases in contact angles due to roughening or texturing surfaces and perturbations to the resulting contact angles. The theory is applied to predicting contact-angle hysteresis on rough surfaces from the hysteresis observable on smooth surfaces and is therefore relevant to predicting roll-off angles for droplets on tilted surfaces. The theory quantitatively predicts a "sticky" surface for Wenzel-type surfaces and a "slippy" surface for Cassie-Baxter-type surfaces. PMID:15518506

  10. Linkage studies in primary open angle glaucoma

    SciTech Connect

    Avramopoulos, D.; Grigoriadu, M. [Institute of Child Health, Athens (Greece); Kitsos, G. [Univ. Eye Clinic of Ioannina (Greece)] [and others

    1994-09-01

    Glaucoma is a leading cause of blindness worldwide. The majority of glaucoma is associated with an open, normal appearing anterior chamber angle and is termed primary open angle glaucoma (POAG, MIM 137760). It is characterized by elevated intraocular pressure and onset in middle age or later. A subset of POAG with juvenile onset has recently been linked to chromosome 1q in two families with autosomal dominant inheritance. Eleven pedigrees with autosomal dominant POG (non-juvenile-onset) have been identified in Epirus, Greece. In the present study DNA samples have been collected from 50 individuals from one large pedigree, including 12 affected individuals. Preliminary results of linkage analysis with chromosome 1 microsatellites using the computer program package LINKAGE Version 5.1 showed no linkage with the markers previously linked to juvenile-onset POAG. Further linkage analysis is being pursued, and the results will be presented.

  11. Kernel density estimation applied to bond length, bond angle, and torsion angle distributions.

    PubMed

    McCabe, Patrick; Korb, Oliver; Cole, Jason

    2014-05-27

    We describe the method of kernel density estimation (KDE) and apply it to molecular structure data. KDE is a quite general nonparametric statistical method suitable even for multimodal data. The method generates smooth probability density function (PDF) representations and finds application in diverse fields such as signal processing and econometrics. KDE appears to have been under-utilized as a method in molecular geometry analysis, chemo-informatics, and molecular structure optimization. The resulting probability densities have advantages over histograms and, importantly, are also suitable for gradient-based optimization. To illustrate KDE, we describe its application to chemical bond length, bond valence angle, and torsion angle distributions and show the ability of the method to model arbitrary torsion angle distributions. PMID:24746022

  12. ASYMPTOTIC OPENING ANGLES FOR COLLIDING-WIND BOW SHOCKS: THE CHARACTERISTIC-ANGLE APPROXIMATION

    SciTech Connect

    Gayley, Kenneth G. [University of Iowa, 203 Van Allen Hall, Iowa City, IA 52245 (United States)

    2009-09-20

    By considering the advection and interaction of the vector momentum flux in highly supersonic spherically diverging winds, we derive a simple analytic description of the asymptotic opening angle of a wind-collision shock cone, in the approximation that the shocked gas is contained in a cone streaming out along a single characteristic opening angle. Both highly radiative and highly adiabatic limits are treated, and their comparison is the novel result. Analytic closed-form expressions are obtained for the inferred wind momentum ratios as a function of the observed shock opening angle, allowing the conspicuous shape of the asymptotic bow shock to be used as a preliminary constraint on more detailed modeling of the colliding winds. In the process, we explore from a general perspective the limitations in applying to the global shock geometry the so-called Dyson approximation, which asserts a local balance in the perpendicular ram pressure across the shock.

  13. Management of angle closure glaucoma

    PubMed Central

    See, Jovina L S; Aquino, Maria Cecilia D; Aduan, Joel; Chew, Paul T K

    2011-01-01

    Primary angle closure glaucoma (PACG) is equally prevalent in Indian in Asian population as the primary open angle glaucoma. Eighty-six percent of people with PACG are in Asia, with approximately 48.0% in China, 23.9% in India and 14.1% in southeast Asia. To understand PACG, it is mandatory to understand its classification and type of presentation with the underlying pathophysiology. The treatment options are medical, laser and/or surgical. The present article provides an overview of PACG. PMID:21150039

  14. Effect of impact angle on vaporization

    NASA Astrophysics Data System (ADS)

    Schultz, Peter H.

    1996-09-01

    Impacts into easily vaporized targets such as dry ice and carbonates generate a rapidly expanding vapor cloud. Laboratory experiments performed in a tenuous atmosphere allow deriving the internal energy of this cloud through well-established and tested theoretical descriptions. A second set of experiments under near-vacuum conditions provides a second measure of energy as the internal energy converts to kinetic energy of expansion. The resulting data allow deriving the vaporized mass as a function of impact angle and velocity. Although peak shock pressures decrease with decreasing impact angle (referenced to horizontal), the amount of impact-generated vapor is found to increase and is derived from the upper surface. Moreover, the temperature of the vapor cloud appears to decrease with decreasing angle. These unexpected results are proposed to reflect the increasing roles of shear heating and downrange hypervelocity ricochet impacts created during oblique impacts. The shallow provenance, low temperature, and trajectory of such vapor have implications for larger-scale events, including enhancement of atmospheric and biospheric stress by oblique terrestrial impacts and impact recycling of the early atmosphere of Mars.

  15. Low angle injection into a supersonic flow

    NASA Technical Reports Server (NTRS)

    Mays, R. B.; Thomas, R. H.; Schetz, J. A.

    1989-01-01

    A study of helium jets injected into a Mach 3 airflow through circular sonic nozzles angled downstream at 15 and 30 deg is presented. An aspirating hot-film probe was employed to measure helium concentrations. The results of Schlieren and nonoshadowgraph photography show the presence of large-scale turbulent structures in the high pressure jets. Concentration data reveal some asymmetries both in the cross section of the jet and in the trajectory of the jet relative to the centerline of the jet. Plotting the decay of maximum concentration with axial distance, it is found that the mixing rate can be increased significantly by increasing the pressure ratio. These low angle jets display good cross-stream penetration.

  16. Weak mixing angle measurements at hadron colliders

    E-print Network

    Di Simone, Andrea; The ATLAS collaboration

    2015-01-01

    The Talk will cover weak mixing angle measurements at hadron colliders ATLAS and CMS in particular. ATLAS has measured the forward-backward asymmetry for the neutral current Drell Yan process in a wide mass range around the Z resonance region using dielectron and dimuon final states with $\\sqrt{s}$ =7 TeV data. For the dielectron channel, the measurement includes electrons detected in the forward calorimeter which extends the covered phase space. The result is then used to extract a measurement of the effective weak mixing angle. Uncertainties from the limited knowledge on the parton distribution functions in the proton constitute a significant part of the uncertainty and a dedicated study is performed to obtain a PDF set describing W and Z data measured previously by ATLAS. Similar studies from CMS will be reported.

  17. Averaging kernel prediction from atmospheric and surface state parameters based on multiple regression for nadir-viewing satellite measurements of carbon monoxide and ozone

    NASA Astrophysics Data System (ADS)

    Worden, H. M.; Edwards, D. P.; Deeter, M. N.; Fu, D.; Kulawik, S. S.; Worden, J. R.; Arellano, A.

    2013-07-01

    A current obstacle to the observation system simulation experiments (OSSEs) used to quantify the potential performance of future atmospheric composition remote sensing systems is a computationally efficient method to define the scene-dependent vertical sensitivity of measurements as expressed by the retrieval averaging kernels (AKs). We present a method for the efficient prediction of AKs for multispectral retrievals of carbon monoxide (CO) and ozone (O3) based on actual retrievals from MOPITT (Measurements Of Pollution In The Troposphere) on the Earth Observing System (EOS)-Terra satellite and TES (Tropospheric Emission Spectrometer) and OMI (Ozone Monitoring Instrument) on EOS-Aura, respectively. This employs a multiple regression approach for deriving scene-dependent AKs using predictors based on state parameters such as the thermal contrast between the surface and lower atmospheric layers, trace gas volume mixing ratios (VMRs), solar zenith angle, water vapor amount, etc. We first compute the singular value decomposition (SVD) for individual cloud-free AKs and retain the first three ranked singular vectors in order to fit the most significant orthogonal components of the AK in the subsequent multiple regression on a training set of retrieval cases. The resulting fit coefficients are applied to the predictors from a different test set of test retrievals cased to reconstruct predicted AKs, which can then be evaluated against the true retrieval AKs from the test set. By comparing the VMR profile adjustment resulting from the use of the predicted vs. true AKs, we quantify the CO and O3 VMR profile errors associated with the use of the predicted AKs compared to the true AKs that might be obtained from a computationally expensive full retrieval calculation as part of an OSSE. Similarly, we estimate the errors in CO and O3 VMRs from using a single regional average AK to represent all retrievals, which has been a common approximation in chemical OSSEs performed to date. For both CO and O3 in the lower troposphere, we find a significant reduction in error when using the predicted AKs as compared to a single average AK. This study examined data from the continental United States (CONUS) for 2006, but the approach could be applied to other regions and times.

  18. Investigating the angle or response and maximum stability of a cohesive granular pile

    E-print Network

    Nowak, Sara Alice, 1982-

    2004-01-01

    In this thesis, I investigate the static and dynamic properties of a granular heap made cohesive by an interstitial fluid. I present the results of experimental work measuring the maximum angle of stability and the angle ...

  19. Ring magnet firing angle control

    Microsoft Academic Search

    M. J. Knott; L. G. Lewis; H. H. Rabe

    1975-01-01

    A device is provided for controlling the firing angles of thyratrons ; (rectifiers) in a ring magnet power supply. A phase lock loop develops a smooth ; ac signal of frequency equal to and in phase with the frequency of the voltage ; wave developed by the main generator of the power supply. A counter that counts ; from zero

  20. Elevation angle dependence of the SMA antenna focus position

    E-print Network

    Satoki Matsushita; Masao Saito; Kazushi Sakamoto; Todd R. Hunter; Nimesh A. Patel; Tirupati K. Sridharan; Robert W. Wilson

    2006-06-21

    We report the measurement results and compensation of the antenna elevation angle dependences of the Sub-millimeter Array (SMA) antenna characteristics. Without optimizing the subreflector (focus) positions as a function of the antenna elevation angle, antenna beam patterns show lopsided sidelobes, and antenna efficiencies show degradations. The sidelobe level increases and the antenna efficiencies decrease about 1% and a few %, respectively, for every 10 degrees change in the elevation angle at the measured frequency of 237 GHz. We therefore obtained the optimized subreflector positions for X (azimuth), Y (elevation), and Z (radio optics) focus axes at various elevation angles for all the eight SMA antennas. The X axis position does not depend on the elevation angle. The Y and Z axes positions depend on the elevation angles, and are well fitted with a simple function for each axis with including a gravity term (cosine and sine of elevation, respectively). In the optimized subreflector positions, the antenna beam patterns show low level symmetric sidelobe of at most a few %, and the antenna efficiencies stay constant at any antenna elevation angles. Using one set of fitted functions for all antennas, the SMA is now operating with real-time focusing, and showing constant antenna characteristics at any given elevation angle.

  1. Operational multi-angle hyperspectral remote sensing for feature detection

    NASA Astrophysics Data System (ADS)

    Bostater, Charles R.; Brooks, Donald K.

    2013-10-01

    Remote sensing results of land and water surfaces from airborne and satellite platforms are dependent upon the illumination geometry and the sensor viewing geometry. Correction of pushbroom hyperspectral imagery can be achieved using bidirectional reflectance factors (BRF's) image features based upon their multi-angle hyperspectral signatures. Ground validation of features and targets utilize non-imaging sensors such as hemispherical goniometers. In this paper, a new linear translation based hyperspectral imaging goniometer system is described. Imagery and hyperspectral signatures obtained from a rotation stage platform and the new linear non-hemispherical goniometer system shows applications and a multi-angle correction approach for multi-angle hyperspectral pushbroom imagery corrections. Results are presented in a manner in order to describe how ground, vessel and airborne based multi-angle hyperspectral signatures can be applied to operational hyperspectral image acquisition by the calculation of hyperspectral anisotropic signature imagery. The results demonstrate the analysis framework from the systems to water and coastal vegetation for exploitation of surface and subsurface feature or target detection based using the multi-angle radiative transfer based BRF's. The hyperspectral pushbroom multi-angle analysis methodology forms a basis for future multi-sensor based multi-angle change detection algorithms.

  2. Optimum Projection Angle for Attaining Maximum Distance in a Soccer Punt Kick

    PubMed Central

    Linthorne, Nicholas P.; Patel, Dipesh S.

    2011-01-01

    To produce the greatest horizontal distance in a punt kick the ball must be projected at an appropriate angle. Here, we investigated the optimum projection angle that maximises the distance attained in a punt kick by a soccer goalkeeper. Two male players performed many maximum-effort kicks using projection angles of between 10° and 90°. The kicks were recorded by a video camera at 100 Hz and a 2 D biomechanical analysis was conducted to obtain measures of the projection velocity, projection angle, projection height, ball spin rate, and foot velocity at impact. The player’s optimum projection angle was calculated by substituting mathematical equations for the relationships between the projection variables into the equations for the aerodynamic flight of a soccer ball. The calculated optimum projection angles were in agreement with the player’s preferred projection angles (40° and 44°). In projectile sports even a small dependence of projection velocity on projection angle is sufficient to produce a substantial shift in the optimum projection angle away from 45°. In the punt kicks studied here, the optimum projection angle was close to 45° because the projection velocity of the ball remained almost constant across all projection angles. This result is in contrast to throwing and jumping for maximum distance, where the projection velocity the athlete is able to achieve decreases substantially with increasing projection angle and so the optimum projection angle is well below 45°. Key points The optimum projection angle that maximizes the distance of a punt kick by a soccer goalkeeper is about 45°. The optimum projection angle is close to 45° because the projection velocity of the ball is almost the same at all projection angles. This result is in contrast to throwing and jumping for maximum distance, where the optimum projection angle is well below 45° because the projection velocity the athlete is able to achieve decreases substantially with increasing projection angle. PMID:24149315

  3. MAGIC SHIMMING: Gradient shimming with magic angle sample spinning

    NASA Astrophysics Data System (ADS)

    Nishiyama, Yusuke; Tsutsumi, Yu; Utsumi, Hiroaki

    2012-03-01

    A simple method to automatically shim NMR samples spinning at the magic angle is introduced based on the gradient shimming approach. The field inhomogeneity along the spinning axis is measured and automatically corrected. The combination of a normal magic angle spinning (MAS) probe, a conventional homospoil gradient, and a set of properly chosen standard room-temperature shims are used to perform the gradient shimming of samples spinning at the magic angle. The resulting 13C NMR adamantane linewidth is less than 1 Hz (0.0078 ppm at 11.7 T).

  4. Moment-angle manifolds and complexes. Lecture notes KAIST'2010

    E-print Network

    Panov, Taras

    2010-01-01

    These are notes of the lectures given during the Toric Topology Workshop at the Korea Advanced Institute of Science and Technology in February 2010. We describe several approaches to moment-angle manifolds and complexes, including the intersections of quadrics, complements of subspace arrangements and level sets of moment maps. We overview the known results on the topology of moment-angle complexes, including the description of their cohomology rings, as well as the homotopy and diffeomorphism types in some particular cases. We also discuss complex-analytic structures on moment-angle manifolds and methods for calculating invariants of these structures.

  5. Compression failure of angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Peel, L. D.; Hyer, M. W.; Shuart, M. J.

    1992-01-01

    Test results from the compression loading of (+ or - Theta/ - or + Theta)(sub 6s) angle-ply IM7-8551-7a specimens, 0 less than or = Theta less than or = 90 degs, are presented. The observed failure strengths and modes are discussed, and typical stress-strain relations shown. Using classical lamination theory and the maximum stress criterion, an attempt is made to predict failure stress as a function of Theta. This attempt results in poor correlation with test results and thus a more advanced model is used. The model, which is based on a geometrically nonlinear theory, and which was taken from previous work, includes the influence of observed layer waviness. The waviness is described by the wave length and the wave amplitude. The theory is briefly described and results from the theory are correlated with test results. It is shown that by using levels of waviness observed in the specimens, the correlation between predictions and observations is good.

  6. Analysis of Ku-band cross section at low incidence angles

    NASA Astrophysics Data System (ADS)

    Chapron, B.; Vandemark, D.

    This study is using airborne Ku-band data to address questions which have implications for both model function development and for advancing our physical understanding of the sea surface. Concurrent measurements of ocean directional spectra, significant wave height, and mean surface roughness are made using the capabilities of the radar ocean wave spectrometer (ROWS). The NASA/GSFC's ROWS is a 15 GHz pulse compressed radar which is a radar sensor designed to measure the direction of the long wave components using spectral analysis of the tilt induced reflectively modulation. The ROWS are modified to cycle at 50 Hz for the scanning spectrometer antenna and a wide beamwidth nadir altimeter mode. This change allows the sensor to simultaneously measure directional wave spectra, wave height, mean square slope parameter, and small scale surface roughness. The surface stress caused by the wind is widely believed to be the predominant quantity related to the Ku-band radar cross section for a wide range of incidence angles. The complete coverage in the quasi specular region provided by one sensor is essential to understand the uncertainties between the scattering model and what is happening on the surface. For this presentation, special attention is devoted to sort out some measurement of the anisotropy associated with the band of high frequencies. Using the other geophysical parameters, comparisons are then made with the classic spectral form currentlyused to describe the wind impact on the sea surface.

  7. Moment-Rotation Hysteresis Behavior of Top and Seat Angle Steel Frame Connections

    Microsoft Academic Search

    Anant R. Kukreti; Ali S. Abolmaali

    1999-01-01

    This paper presents an approach toward formulating analytical models to predict the moment- rotation hysteresis behavior of top and seat angle connections. Experimental results obtained from 12 top and seat angle connection specimens are used to obtain the prediction equations for the parameters defining the moment rotation hysteresis loops of a typical top and seat angle connection. These parameters include

  8. Influence of temperature on divergence angle of a focal telescope used in laser optical communication.

    PubMed

    Zheng, Guoxian; Zhou, Feng; Liu, Jianfeng; Li, Tuotuo; An, Ning; Zhang, Binglong

    2012-06-01

    Divergence angle of antenna is an important parameter in laser optical communication. It determines the power of the receiver terminal. In this paper, the influence of temperature on the divergence angle is discussed. Theoretical analysis and experiment results demonstrate that the relationship between the variance of temperature and of divergence angle is linear. PMID:22714349

  9. The Correlation between Angle Kappa and Ocular Biometry in Koreans

    PubMed Central

    Choi, Se Rang

    2013-01-01

    Purpose To investigate normative angle kappa data and to examine whether correlations exist between angle kappa and ocular biometric measurements (e.g., refractive error, axial length) and demographic features in Koreans. Methods Data from 436 eyes (213 males and 223 females) were analyzed in this study. The angle kappa was measured using Orbscan II. We used ocular biometric measurements, including refractive spherical equivalent, interpupillary distance and axial length, to investigate the correlations between angle kappa and ocular biometry. The IOL Master ver. 5.02 was used to obtain axial length. Results The mean patient age was 57.5 ± 12.0 years in males and 59.4 ± 12.4 years in females (p = 0.11). Angle kappa averaged 4.70 ± 2.70 degrees in men and 4.89 ± 2.14 degrees in women (p = 0.48). Axial length and spherical equivalent were correlated with angle kappa (r = -0.342 and r = 0.197, respectively). The correlation between axial length and spherical equivalent had a negative correlation (r = -0.540, p < 0.001). Conclusions Angle kappa increased with spherical equivalent and age. Thus, careful manipulation should be considered in older and hyperopic patients when planning refractive or strabismus surgery. PMID:24311927

  10. Presumed topiramate-induced bilateral acute angle-closure glaucoma

    Microsoft Academic Search

    James T Banta; Kara Hoffman; Donald L Budenz; Elizenda Ceballos; David S Greenfield

    2001-01-01

    PURPOSE: We describe a case of bilateral angle-closure glaucoma associated with oral topiramate therapy.METHODS: Interventional case report. Case report with echographic illustration.RESULTS: A 51-year-old man developed bilateral acute angle-closure glaucoma 2 weeks after beginning topiramate therapy for bipolar affective disorder. Laser peripheral iridotomy was performed in the right eye without resolution of the acute attack. Echography revealed lens thickening and

  11. SPICAM: status of the experiment, first results and future plans

    NASA Astrophysics Data System (ADS)

    Bertaux, J. L.; Korablev, O.

    SPICAM, a light-weight (4.8 kg) UV-IR instrument on board Mars Express orbiter, is dedicated primarily to the study of the atmosphere and ionosphere of Mars, but has also provided important results on the surface albedo of Mars. A UV spectrometer (118 - 320 nm, resolution 1 nm) is dedicated to nadir viewing, limb viewing and vertical profiling by stellar and solar occultation. An IR spectrometer (1.0-1.7 microns , resolution 0.5-1.2 nm, mass 0.8 kg, new AOTF technology) is dedicated primarily to nadir measurements of H2O abundances. In nadir viewing, the solar spectrum reflected by Mars is analyzed. SPICAM has thus obtained for the first time from an orbiter simultaneous measurements of ozone and H2O, which are found to be anti-correlated as expected on the ground of chemistry consideration: catalytic destruction of ozone from OH and HO2 radicals. SPICAM has also performed the first ever stellar occultation around Mars, and measured for the first time the UV absorption of CO2 in the upper atmosphere of Mars up to 120 km of altitude, yielding a full vertical profile of density and temperature. Over the South pole, the UV albedo is very large, with strong fluctuations. In the near IR, both the CO2 and H2O ice signatures are recognized, showing for the first time without ambiguity the presence of H2O ice in the South polar cap, simultaneously with OMEGA findings.

  12. Capillary rise with velocity-dependent dynamic contact angle.

    PubMed

    Popescu, M N; Ralston, J; Sedev, R

    2008-11-01

    The classic description of the rate of capillary rise given by the Washburn equation, which assumes that the contact angle preserves the equilibrium value at all times, has been recently questioned in the light of the known experimental dependence of the dynamic contact angle on the velocity of the contact line. For a number of such proposed functions of velocity for the dynamic contact angle, we analyze the resulting dependences of the contact angle and of the time of rise, respectively, on the height of the capillary rise. By applying our results to the particular cases of a high-viscosity silicone oil and water, respectively, in a glass capillary, we show that, in general, strong similarities arise between the various approaches and the classic theory in what concerns the time dependence of the capillary rise, which explains the lack of consistent experimental evidence for deviations in the rate of capillary rise from the Washburn equation. However, for a strong dependency of the contact angle on the velocity in the range of small velocities, as in the case of water on glass, one of the models predicts significant deviations even for the time dependence of the capillary rise. Moreover, our results show that the time or height dependence of the contact angle during the capillary rise can clearly discriminate between the various models. PMID:18834162

  13. Small angle neutron scattering and small angle X-ray scattering studies of platinum-loaded carbon foams

    Microsoft Academic Search

    P. U. Sastry; V. K. Aswal; A. G. Wagh

    2008-01-01

    The morphology of carbon nanofoam samples comprising platinum nanoparticles dispersed in the matrix was characterized by small\\u000a angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) techniques. Results show that the structure of pores\\u000a of carbon matrix exhibits a mass (pore) fractal nature and the average radius of the platinum particles is about 2.5 nm. The\\u000a fractal dimension as

  14. Huygens lens for angle compensation

    NASA Astrophysics Data System (ADS)

    Lévesque, Quentin; Bouchon, Patrick; Pardo, Fabrice; Pelouard, Jean-Luc; Haïdar, Riad

    2014-03-01

    Plasmonic lenses are based on complex combinations of nanoscale high aspect ratio slits. We show that their design can be greatly simplified, keeping similar performance while releasing technological constraints. The simplified system, called Huygens lens, consists in a central aperture surrounded by several identical single mode slits in a thin gold layer that does not rely anymore on surface plasmons. The focusing behaviour with respect to the position and number of slits is investigated, and we demonstrate the interest of this design to get compact array of lenses which are able to compensate the angle of incidence of the incoming wave.

  15. Imaging properties of supercritical angle fluorescence optics

    E-print Network

    Enderlein, Jörg

    Imaging properties of supercritical angle fluorescence optics J¨org Enderlein,1,4, Ingo Gregor,1 of supercritical angle fluorescence (SAF) allows for the detection of evanescent modes and thus to confine

  16. Comparison of Trajectory Solid Angle with Geometric Solid Angle in Scattering Theory

    NASA Astrophysics Data System (ADS)

    Wong, Po Kee; Wong, Adam; Wong, Anita

    2002-01-01

    The objective of the paper is openly to invite all physicists, mathematicians and engineers in the world to re-examine and to confirm the ultimate truth and the worldwide impacts of two U.S. Basic Patents No.5,084,232 and No. 5,848,377 which can be obtained from: http://164.195.100.11/netahtml/srchnum.htm The application of Trajectory Solid Angle (TSA) to obtain the correct collision cross-sections in Nuclear Physics and in Astronomy by the example of obtaining the correct scattering cross-section of the well- known Alpha Scattering was shown in a paper IAF-00-J.1.10. entitled " Applications of Trajectory Solid Angle (TSA) and Wong's Angles (WA) Solving Fundamental Problems in Physics and Astronomy " presented and published at the 51st. International Astronautical Congress, 2-6 Oct 2000/Rio de Janeiro, Brazil. The Alpha Scattering was done in theory and in experiment by Sir Rutherford. The differential scattering cross section derived from using the geometric solid angle can be seen from all the text books of physics in the world. However, the differential scattering cross section derived from using the TSA has not been known by most of our colleagues in the world and it is different from the previous results. The present and the previous theoretical results converge to be the same only when the Alpha particle is far away from the stationary heavy nucleus. That was where Sir Rutherford made his measurement and therefore the old theory and the experiment were confirmed. The Alpha Scattering is really similar to the scattering of the Comet Halley by our solar system even though they are under the actions of different force fields. In 1976-79, the senior author of this paper communicated with JPL of NASA and urged JPL to conduct an experiment to confirm the curvature effects of the trajectory of the Comet Halley coming closer to our solar system in those years. It is unfortunate that the communications have never been answered even up to now. Without repeating the analysis, the trajectory equation can be expressed by means of the spherical coordinate system that was shown in the paper IAF-00-J.1.10 Ref. 2 Figure No.1 and in Ref.3 Figure No. 1 for axially symmetric motion. The scattered particle is restricted in a plane surface which is perpendicular to the XOY plane; the particle is coming from the negative Z axis going upward as the altitude angle @ that is measured from the XOY plane as zero degree. After going through all the process as indicated in the above example A. of the paper IAF-00-J.1.10, the differential trajectory solid angle can be obtained as (2 pi (e)(Sin @)^2 d @)/((1+eCos @)^2 + (e Sin @)^2) ^(1/2) that is obviously different from the usual differential geometric solid angle obtained as 2pi Sin @ d@ where e is the eccentricity of the orbit and pi = 3.14159....... This paper will be concentrated in the presentation and publication of the graphical results of numerical data obtained from the above two differential scattering cross-sections in greater detail in order to distinguish the differences by Comparison of the Trajectory Solid Angle (TSA) with the Geometric Solid Angle (GSA) in Scattering Theory for the Central Force Fields.

  17. Folded cavity angled-grating broad-area lasers.

    PubMed

    Zhao, Yunsong; Zhu, Lin

    2013-10-01

    The angled-grating broad-area laser is a promising candidate for high power, high brightness diode laser source. The key point in the design is the angled gratings which can simultaneously support the unique snake-like zigzag lasing mode and eliminate the direct Fabry-Perot (FP) feedback. Unlike a conventional laser waveguide mode, the phase front of the zigzag mode periodically changes along the propagation direction. By use of the mirror symmetry of the zigzag mode, we propose and demonstrate the folded cavity angled-grating broad-area lasers. One benefit of this design is to reduce the required wafer space compared to a regular angled-grating broad-area laser, especially in a long cavity laser for high power operation. Experimental results show that the folded cavity laser exhibits good beam quality in far field with a slightly larger threshold and smaller slope efficiency due to the additional interface loss. PMID:24104317

  18. Neptune high-latitude emission: Dependence of angle on frequency

    NASA Technical Reports Server (NTRS)

    Sawyer, Constance

    1993-01-01

    Smooth broadband radio emission reached a maximum and then cut off as Voyager approached the north magnetic pole of Neptune. The time of each event depends on frequency, yielding information on radio source location, and emission angle. In a preliminary analysis L-shell and magnetic longitude define radio-source locations in a dipole field. The emission angle at each frequency is identified with the angle between the magnetic-field direction at the source and the line of sight to Voyager 2 at the time of emission maximum. At each value of L in the range 6 less than L less than 9, there is one source longitude for which emission angle varies smoothly from greater or equal to 90 deg at 40 kHz to as low as 20 deg at 462 kHz. A more complex magnetic-field model can give a qualitatively different result.

  19. Adaptive control of a vibratory angle measuring gyroscope.

    PubMed

    Park, Sungsu

    2010-01-01

    This paper presents an adaptive control algorithm for realizing a vibratory angle measuring gyroscope so that rotation angle can be directly measured without integration of angular rate, thus eliminating the accumulation of numerical integration errors. The proposed control algorithm uses a trajectory following approach and the reference trajectory is generated by an ideal angle measuring gyroscope driven by the estimate of angular rate and the auxiliary sinusoidal input so that the persistent excitation condition is satisfied. The developed control algorithm can compensate for all types of fabrication imperfections such as coupled damping and stiffness, and mismatched stiffness and un-equal damping term in an on-line fashion. The simulation results show the feasibility and effectiveness of the developed control algorithm that is capable of directly measuring rotation angle without the integration of angular rate. PMID:22163667

  20. Adaptive Control of a Vibratory Angle Measuring Gyroscope

    PubMed Central

    Park, Sungsu

    2010-01-01

    This paper presents an adaptive control algorithm for realizing a vibratory angle measuring gyroscope so that rotation angle can be directly measured without integration of angular rate, thus eliminating the accumulation of numerical integration errors. The proposed control algorithm uses a trajectory following approach and the reference trajectory is generated by an ideal angle measuring gyroscope driven by the estimate of angular rate and the auxiliary sinusoidal input so that the persistent excitation condition is satisfied. The developed control algorithm can compensate for all types of fabrication imperfections such as coupled damping and stiffness, and mismatched stiffness and un-equal damping term in an on-line fashion. The simulation results show the feasibility and effectiveness of the developed control algorithm that is capable of directly measuring rotation angle without the integration of angular rate. PMID:22163667

  1. Planet Impact: What's Your Angle

    NSDL National Science Digital Library

    In this interactive module, students can vary the comet's angle of approach to see the effect of gravity on its trajectory towards Jupiter. The speed and masses of the two bodies are held constant. The goal is for the students to understand the relationship between the distance from the planet and the force of gravity. Students may work independently or in small groups to complete this activity. It may also be done as a teacher-directed activity in the classroom. After completing this module, students will learn about how changing the angle of approach affects the force of gravity on a comet. This module is a part of the online exploration "Planet Impact!" An explanation of the science behind the animations can be found in "Science Scoop." More information on the crash of Shoemaker-Levy 9 on Jupiter can be obtained from "Gravity Gallery" and "Comet News." Detailed teacher pages, identified as Teaching Tips on the title pages of the activity, provide science background information, lesson plan ideas, related resources, and alignment with national education standards.

  2. Optoelectronic Shaft-Angle Encoder Tolerates Misalignments

    NASA Technical Reports Server (NTRS)

    Osborne, Eric P.

    1991-01-01

    Optoelectronic shaft-angle encoder measures angle of rotation of shaft with high precision while minimizing effects of eccentricity and other misalignments. Grooves on disk serve as reference marks to locate reading heads and measure increments of rotation of disk. Shaft-angle encoder, resembling optical compact-disk drive, includes two tracking heads illuminating grooves on disk and measures reflections from them.

  3. Subspace angles and distances between ARMA models

    Microsoft Academic Search

    Katrien De Cock; Bart De Moor

    2000-01-01

    In this paper we define a notion of subspace angles between two ARMA models as the principal angles between the col- umn spaces generated by the observability matrices of the two models extended with the observability matrices of the inverse models. We show that these angles can be calculated via the observability Gramians of concatenations of the two given models

  4. LSNR Airborne LIDAR Mapping System Design and Early Results (Invited)

    NASA Astrophysics Data System (ADS)

    Shrestha, K.; Carter, W. E.; Slatton, K. C.

    2009-12-01

    Low signal-to-noise ratio (LSNR) detection techniques allow for implementation of airborne light detection and range (LIDAR) instrumentation aboard platforms with prohibitive power, size, and weight restrictions. The University of Florida has developed the Coastal Area Tactical-mapping System (CATS), a prototype LSNR LIDAR system capable of single photon laser ranging. CATS is designed to operate in a fixed-wing aircraft flying 600 m above ground level, producing 532 nm, 480 ps, 3 ?J output pulses at 8 kHz. To achieve continuous coverage of the terrain with 20 cm spatial resolution in a single pass, a 10x10 array of laser beamlets is scanned. A Risley prism scanner (two rotating V-coated optical wedges) allows the array of laser beamlets to be deflected in a variety of patterns, including conical, spiral, and lines at selected angles to the direction of flight. Backscattered laser photons are imaged onto a 100 channel (10x10 segmented-anode) photomultiplier tube (PMT) with a micro-channel plate (MCP) amplifier. Each channel of the PMT is connected to a multi-stop 2 GHz event timer. Here we report on tests in which ranges for known targets were accumulated for repeated laser shots and statistical analyses were applied to evaluate range accuracy, minimum separation distance, bathymetric mapping depth, and atmospheric scattering. Ground-based field test results have yielded 10 cm range accuracy and sub-meter feature identification at variable scan settings. These experiments also show that a secondary surface can be detected at a distance of 15 cm from the first. Range errors in secondary surface identification for six separate trials were within 7.5 cm, or within the timing resolution limit of the system. Operating at multi-photon sensitivity may have value for situations in which high ambient noise precludes single-photon sensitivity. Low reflectivity targets submerged in highly turbid waters can cause detection issues. CATS offers the capability to adjust the sensitivity of the sensor by changing the PMT supply voltage. For heavily turbid water, the multi-photon state (2300 V, 2.5*10^5 gain) was not sufficient for feature identification. Extraction of the bottom signal in a heavily turbid suspension necessitated maximum MCP-PMT gain (2500 V, 8*10^5 gain). Extrapolation of bathymetric test results suggest that the density of data points from the sea bottom should be sufficient to establish near-shore depths (up to 5 m) at a spatial resolution of 1 meter, in moderately turbid water. Initial airborne tests over fresh water lakes in central Florida indicate that scan patterns containing near nadir laser points produce strong returns from the surface of the water that cause oscillations in the PMT—preventing the detection of the lake bottom in shallow clear water. These results suggest that it may be necessary to tilt the sensor head in its mount, or use a scan pattern that does not include nadir points, such as a circular scan, for bathymetric mapping. Additional tests are ongoing to optimize the performance of the CATS LSNR airborne LIDAR system for both high spatial resolution terrain mapping and shallow water bathymetric mapping.

  5. Themis observations of whistler wave normal angles

    NASA Astrophysics Data System (ADS)

    Taubenschuss, Ulrich; Khotyaintsev, Yuri; Vaivads, Andris; Santolik, Ondrej; Cully, Christopher; LeContel, Olivier; Angelopoulos, Vassilis

    2014-05-01

    Since spring 2007, the five Themis spacecraft have monitored the vicinity of Earth along orbits, which reach from the dayside solar wind until far down Earth's magnetotail. A magnetometer (SCM) and an electric field instrument (EFI) onboard Themis can be operated in a wave-burst mode which allows for sampling of magnetic and electric waveforms with a rate of up to 8192 Hz. These waveform snapshots have been subject to spectral and polarization analysis. The computed parameters fill a database which is established in the frame of the MAARBLE project ("Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss"). Among those parameters is the direction of the wave-vector with respect to the ambient magnetic field. We present first results on the distribution of those wave normal angles from whistler mode emission. While propagating away from the source region, wave normal angles of whistler are believed to change from parallel to more oblique orientations. We study the wave-vectors both on the nightside, where source regions are close to the equatorial plane, and on the dayside, where sources can also be found at high latitudes.

  6. Survival probability of a Brownian motion in a planar wedge of arbitrary angle.

    PubMed

    Chupeau, Marie; Bénichou, Olivier; Majumdar, Satya N

    2015-03-01

    We study the survival probability and the first-passage time distribution for a Brownian motion in a planar wedge with infinite absorbing edges. We generalize existing results obtained for wedge angles of the form ?/n with n a positive integer to arbitrary angles, which in particular cover the case of obtuse angles. We give explicit and simple expressions of the survival probability and the first-passage time distribution in which the difference between an arbitrary angle and a submultiple of ? is contained in three additional terms. As an application, we obtain the short-time development of the survival probability in a wedge of arbitrary angle. PMID:25871053

  7. Edge effects in angle-ply composite laminates

    NASA Technical Reports Server (NTRS)

    Hsu, P. W.; Herakovich, C. T.

    1977-01-01

    This paper presents the results of a zeroth-order solution for edge effects in angle-ply composite laminates obtained using perturbation techniques and a limiting free body approach. The general solution for edge effects in laminates of arbitrary angle ply is applied to the special case of a (+ or - 45)s graphite/epoxy laminate. Interlaminar stress distributions are obtained as a function of the laminate thickness-to-width ratio and compared to finite difference results. The solution predicts stable, continuous stress distributions, determines finite maximum tensile interlaminar normal stress and provides mathematical evidence for singular interlaminar shear stresses in (+ or - 45) graphite/epoxy laminates.

  8. Measurement of small angle using phase shifted Lau interferometry

    NASA Astrophysics Data System (ADS)

    Disawal, Reena; Dhanotia, Jitendra; Prakash, Shashi

    2014-10-01

    An incoherent white-light source illuminates a set of two identical gratings placed in tandem, resulting in the generation of the Fresnel image. This image is projected onto a reflecting object and the reflected images from the object are projected onto the third grating. The resulting moiré fringes are recorded using CCD camera. Inclination angle of the object is a function of the interferometric phase. Phase shifting interferometry has been used for the determination of interferometric phase. Hence accurate determination of small tilt angle of object surface could be successfully undertaken. Technique is automated and provides high precision in measurement.

  9. Results of the Second SeaWiFS Data Analysis Round Robin, March 2000 (DARR-00)

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Zibordi, Giuseppe; Berthon, Jean-Francois; D'Alimonte, Davide; Maritorena, Stephane; McLean, Scott; Sildam, Juri; McClain, Charles R. (Technical Monitor)

    2001-01-01

    The accurate determination of upper ocean apparent optical properties (AOPs) is essential for the vicarious calibration of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument and the validation of the derived data products. To evaluate the importance of data analysis methods upon derived AOP values, the Second Data Analysis Round Robin (DARR-00) activity was planned during the latter half of 1999 and executed during March 2000. The focus of the study was the intercomparison of several standard AOP parameters: (1) the upwelled radiance immediately below the sea surface, L(sub u)(0(-),lambda); (2) the downward irradiance immediately below the sea surface, E(sub d)(0(-),lambda); (3) the diffuse attenuation coefficients from the upwelling radiance and the downward irradiance profiles, L(sub L)(lambda) and K(sub d)(lambda), respectively; (4) the incident solar irradiance immediately above the sea surface, E(sub d)(0(+),lambda); (5) the remote sensing reflectance, R(sub rs)(lambda); (6) the normalized water-leaving radiance, [L(sub W)(lambda)](sub N); (7) the upward irradiance immediately below the sea surface, E(sub u)(0(-)), which is used with the upwelled radiance to derive the nadir Q-factor immediately below the sea surface, Q(sub n)(0(-),lambda); and (8) ancillary parameters like the solar zenith angle, theta, and the total chlorophyll concentration, C(sub Ta), derived from the optical data through statistical algorithms. In the results reported here, different methodologies from three research groups were applied to an identical set of 40 multispectral casts in order to evaluate the degree to which differences in data analysis methods influence AOP estimation, and whether any general improvements can be made. The overall results of DARR-00 are presented in Chapter 1 and the individual methods used by the three groups and their data processors are presented in Chapters 2-4.

  10. X-31 at High Angle of Attack

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The X-31 aircraft, on a research mission from NASA's Dryden Flight Research Center, Edwards, California, is flying nearly perpendicular to the flight path while performing the Herbst maneuver. Effectively using the entire airframe as a speed brake and using the aircrafts unique thrust vectoring system to maintain control, the pilot rapidly rolls the aircraft to reverse the direction of flight, completing the maneuver with acceleration back to high speed in the opposite direction. This type of turning capability could reduce the turning time of a fighter aircraft by 30 percent. The Herbst maneuver was first conducted in an X-31 on April 29, 1993, in the No. 2 X-31 aircraft by German test pilot Karl-Heinz Lang. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the normal stall angle of attack, which in the X-31 was at a 30-degree angle of attack. During Dryden flight testing, the X-31 aircraft established several milestones. On November 6, 1992, the X-31 achieved controlled flight at a 70-degree angle of attack. On April 29, 1993, the second X-31 successfully executed a rapid minimum-radius, 180-degree turn using a post-stall maneuver, flying well beyond the aerodynamic limits of any conventional aircraft. This revolutionary maneuver has been called the 'Herbst Maneuver' after Wolfgang Herbst, a German proponent of using post-stall flight in air-to-air combat. It is also called a 'J Turn' when flown to an arbitrary heading change. The aircraft was flown in tactical maneuvers against an F/A-18 and other tactical aircraft as part of the test flight program. During November and December 1993, the X-31 reached a supersonic speed of Mach 1.28. In 1994, the X-31 program installed software to demonstrate quasi-tailless operation. The X-31 flight test program was conducted by an international test organization (ITO) managed by the Advanced Research Projects Office (ARPA), known as the Defense Advanced Research Projects Office (DARPA) before March 1993. The ITO included the U.S. Navy and U.S. Air Force, Rockwell Aerospace, the Federal Republic of Germany, Daimler-Benz (formerly Messerschmitt-Bolkow-Blohm and Deutsche Aerospace), and NASA. Gary Trippensee was the ITO director and NASA Project Manager. Pilots came from participating organizations. The X-31 was 43.33 feet long with a wingspan of 23.83 feet. It was powered by a single General Electric P404-GE-400 turbofan engine that produced 16,000 pounds of thrust in afterburner.

  11. X-31 at High Angle of Attack

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The X-31 aircraft, on a research mission from NASA's Dryden Flight Research Center, Edwards, California, is flying nearly perpendicular to the flight path while performing the Herbst maneuver. Effectively using the entire airframe as a speed brake and using the aircraft's unique thrust vectoring system to maintain control, the pilot rapidly rolls the aircraft to reverse the direction of flight, completing the maneuver with acceleration back to high speed in the opposite direction. This type of turning capability could reduce the turning time of a fighter aircraft by 30 percent. The Herbst maneuver was first conducted in an X-31 on April 29, 1993, in the No. 2 X-31 aircraft by German test pilot Karl-Heinz Lang. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the normal stall angle of attack, which in the X-31 was at a 30-degree angle of attack. During Dryden flight testing, the X-31 aircraft established several milestones. On November 6, 1992, the X-31 achieved controlled flight at a 70-degree angle of attack. On April 29, 1993, the second X-31 successfully executed a rapid minimum-radius, 180-degree turn using a post-stall maneuver, flying well beyond the aerodynamic limits of any conventional aircraft. This revolutionary maneuver has been called the 'Herbst Maneuver' after Wolfgang Herbst, a German proponent of using post-stall flight in air-to-air combat. It is also called a 'J Turn' when flown to an arbitrary heading change. The aircraft was flown in tactical maneuvers against an F/A-18 and other tactical aircraft as part of the test flight program. During November and December 1993, the X-31 reached a supersonic speed of Mach 1.28. In 1994, the X-31 program installed software to demonstrate quasi-tailless operation. The X-31 flight test program was conducted by an international test organization (ITO) managed by the Advanced Research Projects Office (ARPA), known as the Defense Advanced Research Projects Office (DARPA) before March 1993. The ITO included the U.S. Navy and U.S. Air Force, Rockwell Aerospace, the Federal Republic of Germany, Daimler-Benz (formerly Messerschmitt-Bolkow-Blohm and Deutsche Aerospace), and NASA. Gary Trippensee was the ITO director and NASA Project Manager. Pilots came from participating organizations. The X-31 was 43.33 feet long with a wingspan of 23.83 feet. It was powered by a single General Electric P404-GE-400 turbofan engine that produced 16,000 pounds of thrust in afterburner.

  12. X-31 at High Angle of Attack

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The X-31 aircraft on a research mission from NASA's Dryden Flight Research Center, Edwards, California, is flying nearly perpendicular to the flight path while performing the Herbst maneuver. Effectively using the entire airframe as a speed brake and using the aircrafts unique thrust vectoring system to maintain control, the pilot rapidly rolls the aircraft to reverse the direction of flight, completing the maneuver with acceleration back to high speed in the opposite direction. This type of turning capability could reduce the turning time of a fighter aircraft by 30 percent. The Herbst maneuver was first conducted in an X-31 on April 29, 1993, in the No. 2 X-31 aircraft by German test pilot Karl-Heinz Lang. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the normal stall angle of attack, which in the X-31 was at a 30-degree angle of attack. During Dryden flight testing, the X-31 aircraft established several milestones. On November 6, 1992, the X-31 achieved controlled flight at a 70-degree angle of attack. On April 29, 1993, the second X-31 successfully executed a rapid minimum-radius, 180-degree turn using a post-stall maneuver, flying well beyond the aerodynamic limits of any conventional aircraft. This revolutionary maneuver has been called the 'Herbst Maneuver' after Wolfgang Herbst, a German proponent of using post-stall flight in air-to-air combat. It is also called a 'J Turn' when flown to an arbitrary heading change. The aircraft was flown in tactical maneuvers against an F/A-18 and other tactical aircraft as part of the test flight program. During November and December 1993, the X-31 reached a supersonic speed of Mach 1.28. In 1994, the X-31 program installed software to demonstrate quasi-tailless operation. The X-31 flight test program was conducted by an international test organization (ITO) managed by the Advanced Research Projects Office (ARPA), known as the Defense Advanced Research Projects Office (DARPA) before March 1993. The ITO included the U.S. Navy and U.S. Air Force, Rockwell Aerospace, the Federal Republic of Germany, Daimler-Benz (formerly Messerschmitt-Bolkow-Blohm and Deutsche Aerospace), and NASA. Gary Trippensee was the ITO director and NASA Project Manager. Pilots came from participating organizations. The X-31 was 43.33 feet long with a wingspan of 23.83 feet. It was powered by a single General Electric P404-GE-400 turbofan engine that produced 16,000 pounds of thrust in afterburner.

  13. Prediction of the noise from a propeller at angle of attack

    NASA Technical Reports Server (NTRS)

    Krejsa, Eugene A.

    1990-01-01

    An analysis is presented to predict the noise of a propeller at angle of attack. The analysis is an extension of that reported by Mani which predicted the change in noise due to angle of attack to both unsteady loading and to azimuthal variation of the radiation efficiency of steady noise sources. Mani's analysis, however, was limited to small angles of attack. The analysis reported herein removes this small angle limitation. Results from the analysis are compared with the data of Woodward for a single rotation propeller and a counter rotating propeller. The comparison shows that including the effect of angle of attack on the steady noise sources significantly improves the agreement with data. Including higher order effects of angle of attack, while changing the predicted noise at far forward and aft angles, has little effect near the propeller plane.

  14. Caustic graphene plasmons with Kelvin angle

    E-print Network

    Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile

    2015-01-01

    A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.

  15. Wide-angle energy-momentum spectroscopy.

    PubMed

    Dodson, Christopher M; Kurvits, Jonathan A; Li, Dongfang; Zia, Rashid

    2014-07-01

    Light emission is defined by its distribution in energy, momentum, and polarization. Here, we demonstrate a method that resolves these distributions by means of wide-angle energy-momentum spectroscopy. Specifically, we image the back focal plane of a microscope objective through a Wollaston prism to obtain polarized Fourier-space momentum distributions, and disperse these two-dimensional radiation patterns through an imaging spectrograph without an entrance slit. The resulting measurements represent a convolution of individual radiation patterns at adjacent wavelengths, which can be readily deconvolved using any well-defined basis for light emission. As an illustrative example, we use this technique with the multipole basis to quantify the intrinsic emission rates for electric and magnetic dipole transitions in europium-doped yttrium oxide (Eu³?:Y?O?) and chromium-doped magnesium oxide (Cr³?:MgO). Once extracted, these rates allow us to reconstruct the full, polarized, two-dimensional radiation patterns at each wavelength. PMID:24978773

  16. Aspect angle dependence of naturally enhanced ion acoustic lines

    NASA Astrophysics Data System (ADS)

    Akbari, H.; Semeter, J. L.

    2014-07-01

    The magnetic aspect angle dependence of naturally enhanced ion acoustic lines (NEIALs) is investigated using two multibeam experiments with the 450 MHz electronically steerable Poker Flat Incoherent Scatter Radar. In each experiment, dynamics in the accompanying auroral activity suggest that the source of free energy for the instability is equally present, in a statistical sense, in a wide portion of sky. Yet strong variations in backscattered power are observed when radar beam direction is altered by only 1°. In our observations, the strongest scattered power appears in the magnetic-zenith direction and weakens with increasing angle between the radar beam and the magnetic lines of force. NEIALs occurring above the F region peak are observed to disappear almost completely at aspect angles as small as 2°. The results are somewhat surprising since previous experiments have detected NEIALs at aspect angles up to 15°. It is shown that during dynamic geophysical conditions, such as the substorm intervals studied in this report, more than one of the generation mechanisms proposed to explain NEIALs may be operating simultaneously. The different mechanisms result in different spectral morphologies and different degrees of sensitivity to the magnetic aspect angle.

  17. The Ratio R dp of the quasielastic nd ? p( nn) to the elastic np ? pn charge-exchange-process yields at the proton emitting angle ? p,lab = 0° over 0.55-2.0 GeV neutron-beam energy region. Comparison of the results with the model-dependent calculations

    NASA Astrophysics Data System (ADS)

    Sharov, V. I.; Morozov, A. A.; Shindin, R. A.; Chernykh, E. V.; Nomofilov, A. A.; Strunov, L. N.

    2009-06-01

    Our new experimental results (see, e.g., Preprint JINR no. E1-2008-61 (Dubna, 2008)) on ratio R dp of the quasielastic charge-exchange yield at the proton emitting angle ? p,lab = 0° for the nd ? p( nn) reaction to the elastic np ? pn charge-exchange yield were presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron-beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8, and 2.0 GeV. In this paper the comparison of the experimental R dp data with the obtained R dp calculations within the impulse approximation by using the invariant-amplitude sets from the GW/VPI phase-shift analysis is made. The R dp values calculated using the set of invariant amplitude data for the elastic np ? pn charge exchange at ? p,CM = 0°, agree with the experimental data. This confirmed the nd ? p( nn) process yield at ? p,CM = 0° is caused by the contribution of the spin-dependent part of the elastic np ? pn charge-exchange reaction. Thus, it has been shown that the obtained experimental R dp results can be used for the Delta-Sigma experimental program to reduce the total ambiguity in the extraction of the amplitude real parts.

  18. Non-Contact Ultrasonic Characterization of Angled Surface Defects

    NASA Astrophysics Data System (ADS)

    Edwards, R. S.; Dutton, B.; Rosli, M. H.; Clough, A. R.

    2011-06-01

    Surface ultrasonic waves have been shown to have many uses in non-destructive testing, in particular for gauging the depth of surface defects. Much of the previous work has assumed that these defects are oriented normal to the surface. However, this is not always the case; for example, rolling contact fatigue in rails propagates at an angle of around 25° to the surface, and this angle may affect the characterisation. We present results using non-contact ultrasonic methods to generate and detect ultrasound on samples with a range of defect angles, and compare these with finite element method (FEM) models. We use both electromagnetic acoustic transducers (EMATs) and laser ultrasound. The depth calibration when measuring ultrasound transmission is considered, and what affect the angle of a defect has. Several other methods of characterising crack depth and angle are also discussed, including the arrival times of reflected and mode-converted waves, the delay in the transmission of the high-frequency Rayleigh wave, and the enhancement of the signal at the defect in both the in-plane and out-of-plane components.

  19. Scattering-angle based filtering of the waveform inversion gradients

    NASA Astrophysics Data System (ADS)

    Alkhalifah, Tariq

    2014-01-01

    Full waveform inversion (FWI) requires a hierarchical approach to maneuver the complex non-linearity associated with the problem of velocity update. In anisotropic media, the non-linearity becomes far more complex with the potential trade-off between the multiparameter description of the model. A gradient filter helps us in accessing the parts of the gradient that are suitable to combat the potential non-linearity and parameter trade-off. The filter is based on representing the gradient in the time-lag normalized domain, in which the low scattering angle of the gradient update is initially muted out in the FWI implementation, in what we may refer to as a scattering angle continuation process. The result is a low wavelength update dominated by the transmission part of the update gradient. In this case, even 10 Hz data can produce vertically near-zero wavenumber updates suitable for a background correction of the model. Relaxing the filtering at a later stage in the FWI implementation allows for smaller scattering angles to contribute higher-resolution information to the model. The benefits of the extended domain based filtering of the gradient is not only it's ability in providing low wavenumber gradients guided by the scattering angle, but also in its potential to provide gradients free of unphysical energy that may correspond to unrealistic scattering angles.

  20. Contact angles of wetting and water stability of soil structure

    NASA Astrophysics Data System (ADS)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Yashin, M. A.; Frid, A. S.; Lazarev, V. I.; Tyugai, Z. N.; Milanovskiy, E. Yu.

    2015-06-01

    From the soddy-podzolic soils and typical chernozems of different texture and land use, dry 3-1 mm aggregates were isolated and sieved in water. As a result, water-stable aggregates and water-unstable particles composing dry 3-1 mm aggregates were obtained. These preparations were ground, and contact angles of wetting were determined by the static sessile drop method. The angles varied from 11° to 85°. In most cases, the values of the angles for the water-stable aggregates significantly exceeded those for the water-unstable components. In terms of carbon content in structural units, there was no correlation between these parameters. When analyzing the soil varieties separately, the significant positive correlation between the carbon content and contact angle of aggregates was revealed only for the loamy-clayey typical chernozem. Based on the multivariate analysis of variance, the value of contact wetting angle was shown to be determined by the structural units belonging to water-stable or water-unstable components of macroaggregates and by the land use type. In addition, along with these parameters, the texture has an indirect effect.

  1. The importance of craniovertebral and cervicomedullary angles in cervicogenic headache

    PubMed Central

    Çoban, Gökçen; Çöven, ?lker; Çifçi, Bilal Egemen; Y?ld?r?m, Erkan; Yaz?c?, Ay?e Canan; Horasanl?, Bahriye

    2014-01-01

    PURPOSE Many studies have indicated that cervicogenic headache may originate from the cervical structures innervated by the upper cervical spinal nerves. To date, no study has investigated whether narrowing of the craniovertebral angle (CVA) or cervicomedullary angle (CMA) affects the three upper cervical spinal nerves. The aim of this study was to investigate the effect of CVA and/or CMA narrowing on the occurrence of cervicogenic headache. MATERIALS AND METHODS Two hundred and five patients diagnosed with cervicogenic headache were included in the study. The pain scores of patients were determined using a visual analog scale. The nonheadache control group consisted of 40 volunteers. CVA and CMA values were measured on sagittal T2-weighted magnetic resonance imaging (MRI), on two occasions by two radiologists. Angle values and categorized pain scores were compared statistically between the groups. RESULTS Intraobserver and interobserver agreement was over 97% for all measurements. Pain scores increased with decreasing CVA and CMA values. Mean angle values were significantly different among the pain categories (P < 0.001). The pain score was negatively correlated with CMA (Spearman correlation coefficient, rs, ?0.676; P < 0.001) and CVA values (rs, ?0.725; P < 0.001). CONCLUSION CVA or CMA narrowing affects the occurrence of cervicogenic headache. There is an inverse relationship between the angle values and pain scores. PMID:24317332

  2. Demonstration of Angle Dependent Casimir Force Between Corrugations

    E-print Network

    A. A. Banishev; J. Wagner; T. Emig; R. Zandi; U. Mohideen

    2013-05-03

    The normal Casimir force between a sinusoidally corrugated gold coated plate and a sphere was measured at various angles between the corrugations using an atomic force microscope. A strong dependence on the orientation angle of the corrugation is found. The measured forces were found to deviate from the proximity force approximation and are in agreement with the theory based on the gradient expansion including correlation effects of geometry and material properties. We analyze the role of temperature. The obtained results open new opportunities for control of the Casimir effect in micromechanical systems.

  3. Solar angles revisited using a general vector approach

    SciTech Connect

    Parkin, Robert E. [Department of Mechanical Engineering, University of Massachusetts, 1 University Avenue, Lowell, MA 01854 (United States)

    2010-06-15

    Rather than follow the standard technique using direction cosines or major axes vectors to define the angles of the sun, we develop the necessary formulae from a 3-tuple vector based analysis. The direction of the sun with respect to a Cartesian coordinate system is defined as a unit vector, as is the orthogonal to a surface intended to accept solar radiation. The vector formulation is powerful and universal. More importantly, the diagrams used to describe the relative motion of the sun with respect to the Earth are quite simple, leading to less confusion when translating the geometry to algebra. An interesting result on the change in solar angle with time follows. (author)

  4. Use of the circular Dammann grating in angle measurement.

    PubMed

    Wen, Fung Jacky; Chung, Po Sheun

    2008-10-01

    We describe a novel method of angle measurement by borrowing the concept of the circular Dammann grating (CDG). A three-order CDG is employed in this experiment. The displacement of the tilted angle can be determined accurately by measuring the projection from the distorted CDG image. This method is controlled only by the initial radius of the image and the converging ratio of the lens. Compared with conventional techniques, this technique has the advantages of a simple design with superior resolution to within 1 degree, low cost, and compactness. A theoretical analysis together with experimental results is presented. PMID:18830311

  5. Demonstration of angle-dependent Casimir force between corrugations.

    PubMed

    Banishev, A A; Wagner, J; Emig, T; Zandi, R; Mohideen, U

    2013-06-21

    The normal Casimir force between a sinusoidally corrugated gold coated plate and a sphere was measured at various angles between the corrugations using an atomic force microscope. A strong dependence on the orientation angle of the corrugation is found. The measured forces were found to deviate from the proximity force approximation and are in agreement with the theory based on the gradient expansion including correlation effects of geometry and material properties. We analyze the role of temperature. The obtained results open new opportunities for control of the Casimir effect in micromechanical systems. PMID:23829717

  6. Teaching Angles by Abstraction from Physical Activities with Concrete Materials

    ERIC Educational Resources Information Center

    White, Paul; Mitchelmore, Michael

    2003-01-01

    An angles teaching sequence was designed, in which students were guided to abstract a general concept from physical activities with concrete materials. The three design principles used were familiarity, similarity recognition, and reification. The resulting teaching sequence was tested in a field study involving 25 teachers of Grades 3-4. The data…

  7. Exploring Dissections of Rectangles into Right-Angled Triangles

    ERIC Educational Resources Information Center

    Griffiths, Martin

    2013-01-01

    In this article we highlight how a simple classroom activity associated with the dissection of rectangles into right-angled triangles can lead on to a number of interesting explorations for students following a post-16 mathematics course. Several results connected with this construction are obtained, and some of the educational benefits of…

  8. Structural studies of ferrofluids by small-angle neutron scattering

    Microsoft Academic Search

    M. Balasoiu; M. V. Avdeev; A. I. Kuklin; V. L. Aksenov; D. Bica; L. Vekas; D. Hasegan; Gy. Torok; L. Rosta; V. Garamus; J. Kohlbrecher

    2004-01-01

    Small-angle neutron scattering (SANS) is a powerful technique for studying the microstructure of ferrofluids under different conditions. The paper reviews recent results obtained from the analysis of SANS data for a number of ferrofluids based on non-polar and polar carriers. Specific features revealed by SANS and their comparison for different types of ferrofluids are discussed. Problems to be solved are

  9. Measurements of CKM Angle Beta from BaBar

    SciTech Connect

    Ulmer, Keith A.; /Colorado U.

    2007-05-23

    We present recent results of hadronic B meson decays related to the CKM angle beta. The data used were collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at the Upsilon(4S) resonance located at the Stanford Linear Accelerator Center.

  10. Quantised Angular Momentum Vectors and Projection Angle Distributions for Discrete

    E-print Network

    Boyer, Edmond

    Quantised Angular Momentum Vectors and Projection Angle Distributions for Discrete Radon that result from the quantisation of angular momentum (QAM) vectors may provide an alternative way to select on Discrete Geometry for Computer Imagery, Szeged : Hungary (2006)" #12;Quantised Angular Momentum Vectors

  11. Multiple target angle tracking using sensor array outputs

    Microsoft Academic Search

    C. R. Rao; L. Zhang; L. C. Zhao

    1993-01-01

    The problem of tracking the directions of arrival of signals from a number of objects using sensor array outputs is considered. An algorithm is developed for estimating the angles associated directly with different objects, avoiding data association methods. Simulation results indicate that the proposed method works well in practice

  12. Spectrogoniometer for measuring planetary surface materials at small phase angles

    NASA Technical Reports Server (NTRS)

    Buratti, Bonnie J.; Smythe, William D.; Nelson, Robert M.; Gharakhani, Vachik

    1988-01-01

    This paper describes an instrument, termed spectrogoniometer, which was designed to measure the bidirectional reflectance properties of planetary surface analogs at very small phase angles. By using a pellicle beam splitter, a highly collimated laser light source, and a carefully aligned apparatus it was possible to measure the reflectance properties of geologic samples under any viewing geometry: the angles of incidence and emission ranging from 0 to 90 deg, and the azimuthal angle ranging from 0 to 360 deg. The results on the effect of porosity are demonstrated by comparing measurements on a compact sample (with a void space of 25 percent) and a fluffy sample (with a void space of 90 percent). The fluffy sample exhibited a 30-percent increase in intensity between 10 and 0 deg, whereas the compact sample exhibited only a 20-percent increase.

  13. Solar cell angle of incidence corrections

    Microsoft Academic Search

    Dale R. Burger; Robert L. Mueller

    1995-01-01

    Literature on solar array angle of incidence corrections was found to be sparse and contained no tabular data for support. This lack along with recent data on 27 GaAs\\/Ge 4 cm by 4 cm cells initiated the analysis presented in this paper. The literature cites seven possible contributors to angle of incidence effects: cosine, optical front surface, edge, shadowing, UV

  14. Practical evaluation of action-angle variables

    SciTech Connect

    Boozer, A.H.

    1984-02-01

    A practical method is described for establishing action-angle variables for a Hamiltonian system. That is, a given nearly integrable Hamiltonian is divided into an exactly integrable system plus a perturbation in action-angle form. The transformation of variables, which is carried out using a few short trajectory integrations, permits a rapid determination of trajectory properties throughout a phase space volume.

  15. The SU(2) action-angle variables

    NASA Technical Reports Server (NTRS)

    Ellinas, Demosthenes

    1993-01-01

    Operator angle-action variables are studied in the frame of the SU(2) algebra, and their eigenstates and coherent states are discussed. The quantum mechanical addition of action-angle variables is shown to lead to a noncommutative Hopf algebra. The group contraction is used to make the connection with the harmonic oscillator.

  16. Aqueous Flow in Open-angle Glaucoma

    Microsoft Academic Search

    Lill-Inger Larsson; Esther S. Rettig; Richard F. Brubaker

    2010-01-01

    ference when comparing aqueous flow during the day- time in subjects with open-angle glaucoma with that in con- trols. However, we did measure a higher aqueous flow at night in the group with open-angle glaucoma, compared with the normal group. The circadian rhythm of aqueous humor flow was present in the subjects with glaucoma. Conclusions: Aqueous flow is not suppressed

  17. A Climbing Class' Reinvention of Angles

    ERIC Educational Resources Information Center

    Fyhn, Anne Birgitte

    2008-01-01

    A previous study shows how a twelve-year-old girl discovers angles in her narrative from a climbing trip. Based on this research, the girl's class takes part in one day of climbing and half a day of follow-up work at school. The students mathematise their climbing with respect to angles and they express themselves in texts and drawings. Their…

  18. Classification procedure in limited angle tomography system

    SciTech Connect

    Chlewicki, W.; Baniukiewicz, P.; Chady, T.; Brykalski, A. [Faculty of Electrical Engineering, Westpomeranian University of Technology, Szczecin (Poland)

    2011-06-23

    In this work we propose the use of limited angle reconstruction algorithms combined with a procedure for defect detection and feature evaluation in three dimensions. The procedure consists of the following steps: acquisition of the X-ray projections, approximated limited angle 3D image reconstruction, and image preprocessing and classification.

  19. Observability Criteria for Angles-Only Navigation

    Microsoft Academic Search

    DAVID C. WOFFINDEN; David K. Geller

    2009-01-01

    The possibility of implementing angles-only navigation for orbital rendezvous, satellite formation flight, and other relative motion applications possesses great potential that is often discarded because of its inherent and misunderstood limitation in determining range. To formally characterize the conditions required for observability, an analytical expression for the observability criteria for angles-only navigation is derived. As anticipated, the criteria clearly shows

  20. Torque Angle Loop Analysis of Synchronous Machines

    Microsoft Academic Search

    A. S. Gopala Rao; D. Thukaram; B. S. Ramakrishna Iyengar

    1986-01-01

    This paper reports the dynamic stability analysis of a single machine infinite bus system through torque angle loop analysis and forms an extension of the work on Block diagrams and torque angle loop analysis of synchronous machines reported by I. Nagy [3]. It aims to incorporate in the machine model, the damper windings (one on each axis) and to compare

  1. An innovative method of calculating target angle based on laser echo in laser imaging system

    NASA Astrophysics Data System (ADS)

    Sun, He; Luo, Qiang; Yang, Yunyi; Cao, Jie; Hao, Qun

    2013-12-01

    Nowadays, lots of studies show the potential value of laser echo intensity in three-dimensional reconstruction of laser detection system. However, raw intensity information could not be used without correcting, since target geometry could also influence laser echo greatly. Target angle that is the angle between laser axis and target normal is important geometry information in intensity correcting. This paper studies the method to calculate target angle, which, as a result, could have great benefits in laser intensity correcting and further in three-dimensional reconstruction. The target angle could be calculated from the mathematical model between the target angle, distance and pulse width based on the laser space translation model presented. Simulation and experimental results show that, the method proposed can calculate the target angle effectively, which have great contribution in laser intensity correction and further in three-dimensional reconstruction.

  2. Verification of measured transmission system phase angles

    SciTech Connect

    Wilson, R.E. [Western Area Power Administration, Montrose, CO (United States)] [Western Area Power Administration, Montrose, CO (United States); Sterlina, P.S. [Macrodyne, Inc., Clifton Park, NY (United States)] [Macrodyne, Inc., Clifton Park, NY (United States)

    1996-10-01

    Measurement of power system phase angle is being studied for use in protective relaying, critical control circuits, and other applications. This paper compares phase angles measured by a synchronized measuring unit during field testing with classical theory. Power system positive sequence voltage and current phasors were recorded during testing of a new 525 kV compensated transmission system. Steady-state phase angles ({delta}) and magnitudes were measured relative to a satellite-based global time standard on synchronized measurement units at two substations. Phase angles were calculated using recorded supervisory system and sending-end values of total power flow. Field measurements of the phase angle across a transmission system differed from calculations by {minus}0.09{degree} on the average, contributing to verification of the new synchronized measurement technique.

  3. Uncertainty incorporated beam angle optimization for IMPT treatment planning

    PubMed Central

    Cao, Wenhua; Lim, Gino J.; Lee, Andrew; Li, Yupeng; Liu, Wei; Ronald Zhu, X.; Zhang, Xiaodong

    2012-01-01

    Purpose: Beam angle optimization (BAO) by far remains an important and challenging problem in external beam radiation therapy treatment planning. Conventional BAO algorithms discussed in previous studies all focused on photon-based therapies. Impact of BAO on proton therapy is important while proton therapy increasingly receives great interests. This study focuses on potential benefits of BAO on intensity-modulated proton therapy (IMPT) that recently began available to clinical cancer treatment. Methods: The authors have developed a novel uncertainty incorporated BAO algorithm for IMPT treatment planning in that IMPT plan quality is highly sensitive to uncertainties such as proton range and setup errors. A linear programming was used to optimize robust intensity maps to scenario-based uncertainties for an incident beam angle configuration. Unlike conventional intensity-modulated radiation therapy with photons (IMXT), the search space for IMPT treatment beam angles may be relatively small but optimizing an IMPT plan may require higher computational costs due to larger data size. Therefore, a deterministic local neighborhood search algorithm that only needs a very limited number of plan objective evaluations was used to optimize beam angles in IMPT treatment planning. Results: Three prostate cancer cases and two skull base chordoma cases were studied to demonstrate the dosimetric advantages and robustness of optimized beam angles from the proposed BAO algorithm. Two- to four-beam plans were optimized for prostate cases, and two- and three-beam plans were optimized for skull base cases. By comparing plans with conventional two parallel-opposed angles, all plans with optimized angles consistently improved sparing at organs at risks, i.e., rectum and femoral heads for prostate, brainstem for skull base, in either nominal dose distribution or uncertainty-based dose distributions. The efficiency of the BAO algorithm was demonstrated by comparing it with alternative methods including simulated annealing and genetic algorithm. The numbers of IMPT plan objective evaluations required were reduced by up to a factor of 5 while the same optimal angle plans were converged in selected comparisons. Conclusions: Uncertainty incorporated BAO may introduce pronounced improvement of IMPT plan quality including dosimetric benefits and robustness over uncertainties, based on the five clinical studies in this paper. In addition, local search algorithms may be more efficient in finding optimal beam angles than global optimization approaches for IMPT BAO. PMID:22894449

  4. Different studies of the global pitch angle of the Milky Way's spiral arms

    NASA Astrophysics Data System (ADS)

    Vallée, Jacques P.

    2015-07-01

    There are many published values for the pitch angle of individual spiral arms, and their wide distribution (from -3° to -28°) begs for various attempts for a single value. Each of four statistical methods used here yields a mean pitch angle in a small range, between -12° and -14° (Table 7, Fig. 2). The final result of our meta-analysis yields a mean global pitch angle in the Milky Way's spiral arms of -13.1° ± 0.6°.

  5. X-31 high angle of attack control system performance

    NASA Technical Reports Server (NTRS)

    Huber, Peter; Seamount, Patricia

    1994-01-01

    The design goals for the X-31 flight control system were: (1) level 1 handling qualities during post-stall maneuvering (30 to 70 degrees angle-of-attack); (2) thrust vectoring to enhance performance across the flight envelope; and (3) adequate pitch-down authority at high angle-of-attack. Additional performance goals are discussed. A description of the flight control system is presented, highlighting flight control system features in the pitch and roll axes and X-31 thrust vectoring characteristics. The high angle-of-attack envelope clearance approach will be described, including a brief explanation of analysis techniques and tools. Also, problems encountered during envelope expansion will be discussed. This presentation emphasizes control system solutions to problems encountered in envelope expansion. An essentially 'care free' envelope was cleared for the close-in-combat demonstrator phase. High angle-of-attack flying qualities maneuvers are currently being flown and evaluated. These results are compared with pilot opinions expressed during the close-in-combat program and with results obtained from the F-18 HARV for identical maneuvers. The status and preliminary results of these tests are discussed.

  6. Plateau iris in Japanese patients with primary angle closure and primary angle closure glaucoma

    PubMed Central

    Mizoguchi, Takanori; Ozaki, Mineo; Wakiyama, Harumi; Ogino, Nobuchika

    2015-01-01

    Purpose To determine the prevalence of plateau iris in Japanese patients with primary angle closure (PAC) and primary angle closure glaucoma (PACG) and analyze the biometric parameters in patients with plateau iris using ultrasound biomicroscopy (UBM). Methods In this cross-sectional observational study, subjects aged >50 years with PAC and PACG who had previously undergone a patent laser peripheral iridotomy underwent UBM in one eye. UBM images were qualitatively analyzed using standardized criteria. Plateau iris in a quadrant was defined by anteriorly directed ciliary body, absent ciliary sulcus, steep iris root from its point of insertion followed by a downward angulation, flat iris plane, and irido-angle contact. At least two quadrants had to fulfill these UBM criteria for an eye to be classified as having plateau iris. A-scan biometry was used to measure anterior segment parameters. Results Ninety-one subjects with PAC (58 subjects) or PACG (33 subjects) and 68 normal controls were recruited. The mean (standard deviation) ages of PAC and PACG patients and normal controls were 73.5 (6.2) and 72.6 (7.3), respectively. Based on UBM criteria, plateau iris was found in 16 eyes (17.6%) of 91 eyes. In these 16 eyes, quadrant-wise analysis showed ten eyes (62.5%) had plateau iris in two quadrants; four eyes (25%) had plateau iris in three quadrants; and two eyes (12.5%) had plateau iris in four quadrants. Anterior chamber depth, lens thickness, axial length, lens position, and relative lens position were not statistically significant between the group having plateau iris and that not having plateau iris, respectively. Conclusion Approximately 20% of Japanese subjects with PAC and PACG with a patent laser peripheral iridotomy were found to have plateau iris on UBM. No morphological difference was noted in the anterior segment of the eye between those with or without plateau iris. PMID:26170608

  7. The Gain of the Energy Under the Optimum Angles of Solar Panels During a Year in Isfahan, Iran

    Microsoft Academic Search

    H. Samareh Salavati Pour; H. Khademhosseini Beheshti; M. Rahnama

    2011-01-01

    In the present article, the optimum tilt and azimuth angles have been calculated utilizing non-isotropic Klein and Hay methods in Isfahan. This is to obtain the maximum monthly total solar energy during a year. In the first part, the optimum tilt angle of the panel with zero azimuth angle is obtained using the isotropic Liu model. The results showed that

  8. Reliability of Beta angle in assessing true anteroposterior apical base discrepancy in different growth patterns

    PubMed Central

    Sundareswaran, Shobha; Kumar, Vinay

    2015-01-01

    Introduction: Beta angle as a skeletal anteroposterior dysplasia indicator is known to be useful in evaluating normodivergent growth patterns. Hence, we compared and verified the accuracy of Beta angle in predicting sagittal jaw discrepancy among subjects with hyperdivergent, hypodivergent and normodivergent growth patterns. Materials and Methods: Lateral cephalometric radiographs of 179 patients belonging to skeletal Classes I, II, and III were further divided into normodivergent, hyperdivergent, and hypodivergent groups based on their vertical growth patterns. Sagittal dysplasia indicators - angle ANB, Wits appraisal, and Beta angle values were measured and tabulated. The perpendicular point of intersection on line CB (Condylion-Point B) in Beta angle was designated as ‘X’ and linear dimension XB was evaluated. Results: Statistically significant increase was observed in the mean values of Beta angle and XB distance in the vertical growth pattern groups of both skeletal Class I and Class II patients thus pushing them toward Class III and Class I, respectively. Conclusions: Beta angle is a reliable indicator of sagittal dysplasia in normal and horizontal patterns of growth. However, vertical growth patterns significantly increased Beta angle values, thus affecting their reliability as a sagittal discrepancy assessment tool. Hence, Beta angle may not be a valid tool for assessment of sagittal jaw discrepancy in patients exhibiting vertical growth patterns with skeletal Class I and Class II malocclusions. Nevertheless, Class III malocclusions having the highest Beta angle values were unaffected. PMID:25810649

  9. Investigation into the influence of diffuser stagger angles on the flow field and performance of a centrifugal compressor

    Microsoft Academic Search

    Guang Xi; Li Zhou; Haiping Ding; Minjian Yuan; Chunmei Zhang

    2007-01-01

    The performance graphs of a centrifugal compressor under different diffuser stagger angles were measured, and the influence\\u000a of different stagger angles of vanes on the stage performance as well as flow field was investigated numerically. The results\\u000a show that the performance graph shifts when the diffuser stagger angle is altered; the influence of different stagger angles\\u000a of vanes on the

  10. Impact angle control of interplanetary shock geoeffectiveness

    NASA Astrophysics Data System (ADS)

    Oliveira, D. M.; Raeder, J.

    2014-10-01

    We use Open Geospace General Circulation Model global MHD simulations to study the nightside magnetospheric, magnetotail, and ionospheric responses to interplanetary (IP) fast forward shocks. Three cases are presented in this study: two inclined oblique shocks, hereafter IOS-1 and IOS-2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30° in relation to the Sun-Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along the Sun-Earth line, with the same Mach number as IOS-1. We find that, in the IOS-1 case, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the FPS compresses the magnetotail from both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in stronger geomagnetic activity. By comparing IOS-2 and FPS, we find that, despite the IOS-2 having a larger Mach number, the FPS leads to a larger geomagnetic response in the nightside ionosphere. As a result, we conclude that IP shocks with similar upstream conditions, such as magnetic field, speed, density, and Mach number, can have different geoeffectiveness, depending on their shock normal orientation.

  11. Adhesion patterns in the microvasculature are dependent on bifurcation angle.

    PubMed

    Lamberti, Giuseppina; Soroush, Fariborz; Smith, Ashley; Kiani, Mohammad F; Prabhakarpandian, Balabhaskar; Pant, Kapil

    2015-05-01

    Particle adhesion in vivo is highly dependent on the microvascular environment comprising of unique anatomical, geometrical, physiological fluid flow conditions and cell-particle and cell-cell interactions. Hence, proper design of vascular-targeted drug carriers that efficiently deliver therapeutics to the targeted cells or tissue at effective concentrations must account for these complex conditions observed in vivo. In this study, we build upon our previous results with the goal of characterizing the effects of bifurcations and their corresponding angle on adhesion of functionalized particles and neutrophils to activated endothelium. Our hypothesis is that adhesion is significantly affected by the type of biochemical interactions between particles and vessel wall as well as the presence of bifurcations and their corresponding angle. Here, we investigate adhesion of functionalized particles (2 ?m and 7 ?m microparticles) to protein coated channels as well as adhesion of human neutrophils to human endothelial cells under various physiological flow conditions in microfluidic bifurcating channels comprising of different contained angles (30°, 60°, 90°, or 120°). Our findings indicate that both functionalized particle and neutrophil adhesion propensity increase with a larger bifurcation angle. Moreover, the difference in the adhesion patterns of neutrophils and rigid, similar sized (7 ?m) particles is more apparent in the junction regions with a larger contained angle. By selecting the right particle size range, enhanced targeted binding of vascular drug carriers can be achieved along with a higher efficacy at optimal drug dosage. Hence, vascular drug particle design needs to be tailored to account for higher binding propensity at larger bifurcation angles. PMID:25708050

  12. Angle sensing with ferromagnetic nanowire arrays

    NASA Astrophysics Data System (ADS)

    Tannous, C.; Gieraltowski, J.

    2014-01-01

    Hysteresis loops and Ferromagnetic Resonance (FMR) linewidths of Nickel ferromagnetic nanowire arrays are measured versus angle ?H between the applied magnetic field angle and the common nanowire axis. Using Preisach analysis, we extract from the hysteresis loop an interaction parameter ?i that strongly depends on ?H. Extending the analysis to FMR lineshapes, we deduce a strong dependence of the FMR field linewidth ?H on ?H through the interaction parameter ?i. Existence of a link between static (hysteresis) and dynamic (FMR) cases through ?H might be exploited in contactless absolute angle sensing devices that could compete with inductive, Hall, and magnetoresistive devices.

  13. Orientation Angles of a Pulsar's Polarization Vector

    E-print Network

    Mark M. McKinnon

    2006-03-17

    A statistical model of the polarization of pulsar radio emission is used to derive the general statistics of a polarization vector's orientation angles. The theoretical distributions are compared with orientation angle histograms computed from single-pulse, polarization observations of PSR B2020+28. The favorable agreement between the theoretical and measured distributions lends support to the underlying assumptions of the statistical model, and demonstrates, like recent work on other pulsars, that the handedness of circular polarization is associated with the radiation's orthogonally polarized modes. Comprehensive directional statistics of the vector's orientation angles are also derived, and are shown to follow the Watson bipolar and Fisher distributions in its limiting forms.

  14. Visual angle model for car-following theory

    NASA Astrophysics Data System (ADS)

    Jin, Sheng; Wang, Dian-Hai; Huang, Zhi-Yi; Tao, Peng-Fei

    2011-06-01

    The vast majority of car-following models are lack of the consideration of human drivers' characteristics. Based on the fact that each driver of a following vehicle perceives closing-in or shying-away a leading vehicle in front of him/her, primarily due to changes in the apparent size of the leading vehicle, we improved the full velocity difference (FVD) model and presented a visual angle car-following model. This model is in view of the stimulus-response framework and uses the visual angle and the change rate of the visual angle as stimulus. Results from linear analysis showed that the neutral stability line is asymmetry and the width of the leading vehicle has a great impact on the stability of traffic flow. Numerical simulations obtained the same results as theoretical analysis clearly such as density wave, shrinking hysteresis, asymmetry and wide scattering. Thus, the introducing of the visual angle can explain some complex nature of traffic flow and contribute to the design of more realistic car-following models.

  15. Diminution of contact angle hysteresis under the influence of an oscillating force.

    PubMed

    Manor, Ofer

    2014-06-17

    We suggest a simple quantitative model for the diminution of contact angle hysteresis under the influence of an oscillatory force invoked by thermal fluctuations, substrate vibrations, acoustic waves, or oscillating electric fields. Employing force balance rather than the usual description of contact angle hysteresis in terms of Gibbs energy, we highlight that a wetting system, such as a sessile drop or a bubble adhered to a solid substrate, appears at long times to be partially or fully independent of contact angle hysteresis and thus independent of static friction forces, as a result of contact line pinning. We verify this theory by studying several well-known experimental observations such as the approach of an arbitrary contact angle toward the Young contact angle and the apparent decrease (or increase) in an advancing (or a receding) contact angle under the influence of an external oscillating force. PMID:24856418

  16. Study on the effect of nonuniform polarization angles on coherently combined fiber lasers

    NASA Astrophysics Data System (ADS)

    Ren, Guangsen; Xu, Xiaojun; Wu, Wuming; Ma, Haotong; Ning, Yu

    2015-06-01

    The effect of nonuniform polarization angles on coherently combined fiber laser beams is analyzed numerically by using statistical methods. Beam propagation factor (BPF) is used to evaluate the quality of the combined beam. The numerical analysis shows that the reduction in beam quality caused by nonuniform polarization angles is relatively small for a phased fiber laser array. The effect of the nonuniform polarization angles and the vacancy factor are decoupled. Enlarging the array number does not weaken the influence of polarization-angle fluctuation. The results above are valid for an array with a large number of lasers or an array consisting of lasers with polarization-angle fluctuation. The mechanism of beam quality degeneration due to nonuniform polarization angle is also discussed.

  17. Estimation of deviation angle for axial-flow compressor blade sections using inviscid-flow solutions

    NASA Technical Reports Server (NTRS)

    Miller, M. J.

    1974-01-01

    Development of a method of estimating deviation angles by analytical procedures was begun. Solutions for inviscid, irrotational flow in the blade-to-blade plane were obtained with a finite-difference calculation method. Deviation angles for a plane cascade with a rounded trailing edge were estimated by using the inviscid-flow solutions and three trailing-edge hypotheses. The estimated deviation angles were compared with existing experimental data over a range of incidence angles at inlet flow angles of 30 deg and 60 deg. The results indicate that deviation angles can be estimated accurately (within 1 deg) by using one of the three trailing-edge hypotheses, but only when pressure losses are low. A new trailing-edge hypotheses is presented which is suitable (for the cascade considered) for both low- and high-loss operating points.

  18. The effect of vapor incidence angle upon thin film columnar growth

    SciTech Connect

    Mazor, A.; Bukiet, B.G.; Srolovitz, D.J.

    1988-01-01

    We present a generalized theory for the growth of columnar microstructure in vapor deposited thin films under the joint influence of a constant uniform deposition flux coming down with arbitrarily chosen incidence angle, and surface diffusion. The dependences of the Zone I to Zone II transition temperature, and the characteristic length scales associated with the unstable modes on the deposition angle are predicted. The surface morphology is obtained as a function of vapor incidence angle. For a specific deposition angle, there is a one-parameter family of steady-state surface profiles which corresponds to a range of possible columnar orientation angles, among which only one angle is associated with the tangent rule. These results agree with experimental observations. 10 refs., 6 figs.

  19. Factors influencing the effective spray cone angle of pressure-swirl atomizers

    NASA Technical Reports Server (NTRS)

    Chen, S. K.; Lefebvre, A. H.; Rollbuhler, J.

    1992-01-01

    The spray cone angles produced by several simplex pressure-swirl nozzles are examined using three liquids whose viscosities range from 0.001 to 0.012 kg/ms (1 to 12 cp). Measurements of both the visible spray cone angle and the effective spray cone angle are carried out over wide ranges of injection pressure and for five different values of the discharge orifice length/diameter ratio. The influence of the number of swirl chamber feed slots on spray cone angle is also examined. The results show that the spray cone angle widens with increase in injection pressure but is reduced by increases in liquid viscosity and/or discharge orifice length/diameter ratio. Variation in the number of swirl chamber feed slots between one and three has little effect on the effective spray cone angle.

  20. Bit error rate performance for head skew angle in shingled magnetic recording using dual reader heads

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Osawa, H.; Okamoto, Y.; Kanai, Y.; Muraoaka, H.

    2015-05-01

    The two-dimensional magnetic recording (TDMR) exploits two-dimensional signal processing using the neighboring read-back waveforms. We allocate dual readers for the intended tracks and evaluate the effects of head skew angle on the bit error rate performance in partial response class-I maximum likelihood system with a two-dimensional finite impulse response filter using two read-back waveforms under TDMR R/W channel specifications of 4 Tbit/in.2. The results show that the effect of positive skew angle is larger than that of negative skew angle, and the center of skew angle should be shifted to minus direction.

  1. A method for measuring the base angle of axicon lens based on chromatic dispersion

    NASA Astrophysics Data System (ADS)

    Zhang, Yunbo; Zeng, Aijun; Wang, Ying; Huang, Huijie

    2015-07-01

    A method for measuring the base angle of axicon lens is presented. This method utilizes two coaxial laser beams with different wavelengths. When the two laser beams passing through the axicon lens, there will be a small divergence angle between them resulted from chromatic dispersion. After collected by an achromatic lens, these two laser beams will generate two spots on an image camera. The base angle can be figured out with the distance between two spots recorded by the image sensor. Furthermore, this method can also be used to calculate the cone angle of axicon lens.

  2. Nanometer scale high-aspect-ratio trench etching at controllable angles using ballistic reactive ion etching

    SciTech Connect

    Cybart, Shane; Roediger, Peter; Ulin-Avila, Erick; Wu, Stephen; Wong, Travis; Dynes, Robert

    2012-11-30

    We demonstrate a low pressure reactive ion etching process capable of patterning nanometer scale angled sidewalls and three dimensional structures in photoresist. At low pressure the plasma has a large dark space region where the etchant ions have very large highly-directional mean free paths. Mounting the sample entirely within this dark space allows for etching at angles relative to the cathode with minimal undercutting, resulting in high-aspect ratio nanometer scale angled features. By reversing the initial angle and performing a second etch we create three-dimensional mask profiles.

  3. THERMAL BUCKLING OF THICK ANTISYMMETRIC ANGLE-PLY LAMINATES

    Microsoft Academic Search

    T. R. Tauchert

    1987-01-01

    The buckling behavior of moderately thick antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise is analyzed. Transverse shear deformation is accounted for by employing the thermoelastic version of the Reissner-Mindlin theory. Results for the classical thin-plate theory are obtained as a special case. Numerical results are presented for fiber-reinforced laminates and show the effects

  4. The Ratio R{sub dp} of the quasielastic nd {yields} p(nn) to the elastic np {yields} pn charge-exchange-process yields at the proton emitting angle {theta}{sub p,lab} = 0 deg. over 0.55-2.0 GeV neutron-beam energy region. Comparison of the results with the model-dependent calculations

    SciTech Connect

    Sharov, V. I., E-mail: sharov@sunhe.jinr.ru; Morozov, A. A.; Shindin, R. A.; Chernykh, E. V.; Nomofilov, A. A.; Strunov, L. N. [Joint Institute for Nuclear Research (Russian Federation)

    2009-06-15

    Our new experimental results (see, e.g., Preprint JINR no. E1-2008-61 (Dubna, 2008)) on ratio R{sub dp} of the quasielastic charge-exchange yield at the proton emitting angle {theta}{sub p,lab} = 0 deg. for the nd {yields} p(nn) reaction to the elastic np {yields} pn charge-exchange yield were presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron-beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8, and 2.0 GeV. In this paper the comparison of the experimental R{sub dp} data with the obtained R{sub dp} calculations within the impulse approximation by using the invariant-amplitude sets from the GW/VPI phase-shift analysis is made. The R{sub dp} values calculated using the set of invariant amplitude data for the elastic np {yields} pn charge exchange at {theta}{sub p,CM} = 0 deg., agree with the experimental data. This confirmed the nd {yields} p(nn) process yield at {theta}{sub p,CM} = 0 deg. is caused by the contribution of the spin-dependent part of the elastic np {yields} pn charge-exchange reaction. Thus, it has been shown that the obtained experimental R{sub dp} results can be used for the Delta-Sigma experimental program to reduce the total ambiguity in the extraction of the amplitude real parts.

  5. A highly accurate dynamic contact angle algorithm for drops on inclined surface based on ellipse-fitting.

    PubMed

    Xu, Z N; Wang, S Y

    2015-02-01

    To improve the accuracy in the calculation of dynamic contact angle for drops on the inclined surface, a significant number of numerical drop profiles on the inclined surface with different inclination angles, drop volumes, and contact angles are generated based on the finite difference method, a least-squares ellipse-fitting algorithm is used to calculate the dynamic contact angle. The influences of the above three factors are systematically investigated. The results reveal that the dynamic contact angle errors, including the errors of the left and right contact angles, evaluated by the ellipse-fitting algorithm tend to increase with inclination angle/drop volume/contact angle. If the drop volume and the solid substrate are fixed, the errors of the left and right contact angles increase with inclination angle. After performing a tremendous amount of computation, the critical dimensionless drop volumes corresponding to the critical contact angle error are obtained. Based on the values of the critical volumes, a highly accurate dynamic contact angle algorithm is proposed and fully validated. Within nearly the whole hydrophobicity range, it can decrease the dynamic contact angle error in the inclined plane method to less than a certain value even for different types of liquids. PMID:25725885

  6. SOLARMAX/Electron Pitch Angle Anisotropy Distributions

    NASA Technical Reports Server (NTRS)

    McKenzie, David L.; Anderson, Phillip C.

    2002-01-01

    This final research report summarizes the scientific work performed by The Aerospace Corporation on SOLARMAX/Electron Pitch Angle Anisotropy Distributions. The period of performance was from June 1, 2000 to December 31, 2001.

  7. Choroid Plexus Papilloma of the Cerebellopontine Angle

    PubMed Central

    Panizza, B. J.; Jackson, A.; Ramsden, R. T.; Lye, R. H.

    1992-01-01

    We report a case of a transdural choroid plexus papilloma of the cerebellopontine angle in a 23-year-old woman. Choroid plexus papillomas are rare intracranial tumors, usually occurring intraventricularly. Those found in the cerebellopontine angle are uncommon and almost always subdural. The investigation, treatment, and follow-up are discussed. ImagesFigure 1Figure 2p156-cFigure 2Figure 3Figure 4Figure 5 PMID:17170859

  8. Computing Large-Angle Transients In Structures

    NASA Technical Reports Server (NTRS)

    Housner, Jerrold M.; Mitchum, Maria V.; Abrahamson, A. Louis; Chang, Che-Wei; Powell, Michael G.; Wu, Shih-Chin; Bingel, Brandford D.; Theophilos, Pauline M.

    1992-01-01

    LATDYN is computer code for calculating large-angle transient dynamics of flexible articulating structures and mechanisms including joints about which members rotate through large angles. Extends and brings together some of aspects of finite-element analysis of structures, dynamics of multiple bodies, and analysis of control systems. Combines significant portions of their distinct capabilities into one analysis software tool. Software consists of three FORTRAN computer programs: LATDYN program, Preprocessor, and Postprocessor. Written in FORTRAN 77.

  9. Neutron spin echo scattering angle measurement (SESAME)

    SciTech Connect

    Pynn, R.; Fitzsimmons, M.R.; Fritzsche, H.; Gierlings, M.; Major, J.; Jason, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); National Research Council, Canada, SIMS, Chalk River Laboratories, Chalk River, Ontario K0J 1P0 (Canada); Hahn-Meitner-Institut, Glienicker Str. 100, D-14109, Berlin (Germany); Max-Planck-Institut fuer Metallforschung, Heisenbergstr 3, D-70569, Stuttgart (Germany); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2005-05-15

    We describe experiments in which the neutron spin echo technique is used to measure neutron scattering angles. We have implemented the technique, dubbed spin echo scattering angle measurement (SESAME), using thin films of Permalloy electrodeposited on silicon wafers as sources of the magnetic fields within which neutron spins precess. With 30-{mu}m-thick films we resolve neutron scattering angles to about 0.02 deg. with neutrons of 4.66 A wavelength. This allows us to probe correlation lengths up to 200 nm in an application to small angle neutron scattering. We also demonstrate that SESAME can be used to separate specular and diffuse neutron reflection from surfaces at grazing incidence. In both of these cases, SESAME can make measurements at higher neutron intensity than is available with conventional methods because the angular resolution achieved is independent of the divergence of the neutron beam. Finally, we discuss the conditions under which SESAME might be used to probe in-plane structure in thin films and show that the method has advantages for incident neutron angles close to the critical angle because multiple scattering is automatically accounted for.

  10. The EUVE Right Angle Program (RAP)

    NASA Astrophysics Data System (ADS)

    Sommers, J.; Christian, D.; Craig, N.; Jessop, H.; Stroozas, B.

    1996-05-01

    The Extreme Ultraviolet Explorer (EUVE ) has three scanning telescopes that observe in a direction perpendicular to that of the primary guest observer (GO) telescope---the Deep Survey/Spectrometer (DS/S). During the first 6 months of the EUVE mission, the scanning telescopes were used to conduct an all-sky survey consisting of short exposures ( ~ 500 s) of the entire sky between 58--740 Angstroms . These telescopes are now being used during GO observations to conduct simultaneous long exposure (typically 40+ ks) observations as part of the very successful---and publicly accessible---EUVE Right Angle Program (RAP). To date, the EUVE RAP has provided photometric and timing data on late-type stars and CVs and has been responsible for detecting dozens of previously unknown extreme ultraviolet sources, including many stars without optical counterparts. This poster presents some of the exciting results found with EUVE RAP data, along with general information about the program and instructions for submitting RAP proposals. This work is supported by NASA contract NAS5-29298.

  11. Studies of the dynamic contact angle

    NASA Astrophysics Data System (ADS)

    Siekmann, Julius; Zimmermann, Elisabeth

    The factors affecting the contact or boundary angle (theta) between a gas-liquid interface and a solid vertical wall are investigated experimentally, with a focus on the dynamic case where a solid object is immersed in a liquid. The apparatus employs a high-precision five-phase step motor to immerse a glass plate or circular cylinder into ethylene glycol or glycerine at 20 C and then retract it, an He-Ne-laser/Xe-flashlamp illumination system, and an optical bench equipped with a microscope and camera. The results are presented in a graph, and the relationships between theta and the six parameters gravity, fluid density and dynamic viscosity, surface tension, characteristic length, and solid-body velocity are explored. Regression analysis gives the dependence equation theta = 175 x (Ca exp -0.81)(Fr exp 0.5)(M exp 0.23), where Ca is the capillarity (Weber number divided by Reynolds number), Fr is the Froude number, and M is the Morton number.

  12. Impact Angle Control of Interplanetary Shock Geoeffectiveness

    E-print Network

    Oliveira, D M

    2015-01-01

    We use OpenGGCM global MHD simulations to study the nightside magnetospheric, magnetotail, and ionospheric responses to interplanetary (IP) fa st forward shocks. Three cases are presented in this study: two inclined oblique shocks, here after IOS-1 and IOS-2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30$^o$ in relation to the Sun-Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along the Sun-Earth line, with the same Mach number as IOS-1. We find that, in the IOS-1 case, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the FPS compresses the magnetotail from both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in stronger...

  13. Geometric orientation by humans: angles weigh in.

    PubMed

    Lubyk, Danielle M; Dupuis, Brian; Gutiérrez, Lucio; Spetch, Marcia L

    2012-06-01

    Human participants were trained to navigate to two geometrically equivalent corners of a parallelogram-shaped virtual environment. The unique shape of the environment combined three distinct types of geometric information that could be used in combination or in isolation to orient and locate the goals: the angular amplitudes of the corners, the relative wall length relationships, and the principal axis of symmetry. In testing, participants were placed in manipulated versions of the training environment that tested which types of geometry they had encoded and how angular information weighed in against the other two geometric properties. The test environments were (a) a rectangular environment that removed the angular information, (b) a rhombic environment that removed wall length information and drastically reduced the principal axis, and (c) a reverse-parallelogram-shaped environment that placed angular information against both wall length and principal axis information. Participants chose accurately in the rectangular and rhombus environments, despite the removal of one of the cues. In the conflict test, participants preferred corners with the correct angular amplitudes over corners that were correct according to both wall length relationships and the principal axis. These results are comparable to recent findings with pigeons and suggest that angles are a salient orientation cue for humans. PMID:22382695

  14. Polarimetric mapping of the Moon at a phase angle near the polarization minimum

    Microsoft Academic Search

    Yu. Shkuratov; N. Opanasenko; A. Opanasenko; E. Zubko; S. Bondarenko; V. Kaydash; G. Videen; Yu. Velikodsky; V. Korokhin

    2008-01-01

    At small phase angles the light scattered by the Moon reveals a negative polarization branch whose average amplitude is 1%. We present results of polarimetric mappings of the Moon in Pmin at a phase angle near 11°. The observations were carried out with the Kharkov 50-cm telescope at the Maidanak Observatory (Middle Asia) using a polarizing filter. A thorough calibration

  15. Broadband "infinite-speed" magic-angle spinning NMR spectroscopy.

    PubMed

    Hu, Yan-Yan; Levin, E M; Schmidt-Rohr, Klaus

    2009-06-24

    High-resolution magic-angle spinning NMR of high-Z spin-1/2 nuclei such as (125)Te, (207)Pb, (119)Sn, (113)Cd, and (195)Pt is often hampered by large (>1000 ppm) chemical-shift anisotropies, which result in strong spinning sidebands that can obscure the centerbands of interest. In various tellurides with applications as thermoelectrics and as phase-change materials for data storage, even 22-kHz magic-angle spinning cannot resolve the center- and sidebands broadened by chemical-shift dispersion, which precludes peak identification or quantification. For sideband suppression over the necessary wide spectral range (up to 200 kHz), radio frequency pulse sequences with few, short pulses are required. We have identified Gan's two-dimensional magic-angle-turning (MAT) experiment with five 90 degrees pulses as a promising broadband technique for obtaining spectra without sidebands. We have adapted it to broad spectra and fast magic-angle spinning by accounting for long pulses (comparable to the dwell time in t(1)) and short rotation periods. Spectral distortions are small and residual sidebands negligible even for spectra with signals covering a range of 1.5 gammaB(1), due to a favorable disposition of the narrow ranges containing the signals of interest in the spectral plane. The method is demonstrated on various technologically interesting tellurides with spectra spanning up to 170 kHz, at 22 kHz MAS. PMID:19489580

  16. Contact angle hysteresis and pinning at periodic defects in statics.

    PubMed

    Iliev, Stanimir; Pesheva, Nina; Nikolayev, Vadim S

    2014-07-01

    This article deals with the theoretical prediction of the wetting hysteresis on nonideal solid surfaces in terms of the surface heterogeneity parameters. The spatially periodical chemical heterogeneity is considered. We propose precise definitions for both the advancing and the receding contact angles for the Wilhelmy plate geometry. It is well known that in such a system, a multitude of metastable states of the liquid meniscus occurs for each different relative position of the defect pattern on the plate with respect to the liquid level. As usual, the static advancing and receding angles are assumed to be a consequence of the preceding contact line motion in the respective direction. It is shown how to select the appropriate states among all metastable states. Their selection is discussed. The proposed definitions are applicable to both the static and the dynamic contact angles on heterogeneous surfaces. The static advancing and receding angles are calculated for two examples of periodic heterogeneity patterns with sharp borders: the horizontal alternating stripes of a different wettability (studied analytically) and the doubly periodic pattern of circular defects on a homogeneous base (studied numerically). The wetting hysteresis is determined as a function of the defect density and the spatial period. A comparison with the existing results is carried out. PMID:25122314

  17. IMU-Based Joint Angle Measurement for Gait Analysis

    PubMed Central

    Seel, Thomas; Raisch, Jorg; Schauer, Thomas

    2014-01-01

    This contribution is concerned with joint angle calculation based on inertial measurement data in the context of human motion analysis. Unlike most robotic devices, the human body lacks even surfaces and right angles. Therefore, we focus on methods that avoid assuming certain orientations in which the sensors are mounted with respect to the body segments. After a review of available methods that may cope with this challenge, we present a set of new methods for: (1) joint axis and position identification; and (2) flexion/extension joint angle measurement. In particular, we propose methods that use only gyroscopes and accelerometers and, therefore, do not rely on a homogeneous magnetic field. We provide results from gait trials of a transfemoral amputee in which we compare the inertial measurement unit (IMU)-based methods to an optical 3D motion capture system. Unlike most authors, we place the optical markers on anatomical landmarks instead of attaching them to the IMUs. Root mean square errors of the knee flexion/extension angles are found to be less than 1° on the prosthesis and about 3° on the human leg. For the plantar/dorsiflexion of the ankle, both deviations are about 1°. PMID:24743160

  18. Magnetic aspect angle effects in radar aurora at 48. 5 MHz, corrected for refraction

    SciTech Connect

    Hall, G.; Moorcroft, D.R. (Univ. of Western Ontario, London (Canada))

    1992-12-01

    It is now widely recognized that at lower VHF frequencies, refraction by electron density structures in the auroral E region can greatly affect the character of radio auroral backscatter, making the quantitative study of magnetic aspect angle effects difficult or impossible. In the present study of data taken with the 48.5-MHz Bistatic Auroral Radar System (BARS) in central Canada, these difficulties have been minimized by using only data obtained from spatially and temporally uniform events. After correcting for effects of refraction, it has been found that true large aspect angle backscatter occurs for magnetic aspect angles exceeding 6[degrees]. Doppler velocities from the smaller aspect angle Red Lake radar behaved as if proportional to the line-of-sight component of the convection drift velocity; the resulting flow directions were found to be in good agreement with estimates obtained from magnetometers located in the BARS field of view. The constant of proportionality between the radar velocity and the drift velocity component appears to decrease by a factor of approximately 2 as the aspect angle increases from 3[degrees] to 6[degrees]. At 3[degrees] aspect angle, the backscatter power decreased with increasing aspect angle by about 13 dB/deg (the aspect sensitivity), similar to what has been found in other studies at UHF. In common with those other studies this aspect sensitivity is found to decrease with increasing aspect angle, but more rapidly, falling to less than 4 dB/deg at aspect angles of 5[degrees]. In contrast to previous studies at small aspect angle, there is no evidence of a dependence of backscattered power on the flow angle, the angle between the radar line of sight and the direction of E [times] B drift.

  19. Contact-angle of water drop on a sloped water repellent soil

    NASA Astrophysics Data System (ADS)

    Arye, Gilboa; Bachmann, Jörg

    2015-04-01

    Soil water repellency is a well-known phenomenon worldwide and currently well documented in the scientific literature. Most methods used to characterize the magnitude and/or persistency of soil water repellency is directly or indirectly related to the initial advancing contact angle at the solid-liquid-vapor interface. These methods are commonly involved by placing a water (or solution) drops on horizontal surface of water repellent soil (WRS)particles attached to a plane surface. Under natural conditions, however, a soil surface layer is mostly sloped due to micro and/or macro topography. Therefore, the formation of advancing contact angle (downhill) and receding contact angle (uphill) should be considered, rather than a unique value of the contact angle. The difference between the advancing and receding contact angle values is defined as the contact angle hysteresis, commonly attributed to surface roughness and/or chemical heterogeneities. For a given tilt angle, a water drop exceeding a critical volume will slide downhill. Alternatively, for a given drop volume, a critical sliding angle can be defined. Measurements of advancing, receding and sliding angles on sloped WRS is indispensable for our understanding on water adhesion due to hysteresis and may provide critical values for predicting the initiation of water runoff in sloped landscapes on the micro and macro scales of WRS. Accordingly, the main objective of this study was to measure the advancing and receding contact angles on a sloped WRS as a function of: i) water drop volume, ii) particle size distribution and iii) surface slope. The measurements of contact angles on sloped WRS were taken with an advanced goniometer microscope (OCA20, DataPhysics) with external tilting device and SCA20 software for analyzing contact angles highly resolved with respect to time and spatial scales. The results obtained will be presented and the rolling-drop-criteria will be discussed.

  20. The angular distributions of ultraviolet spectral irradiance at different solar elevation angles under clear sky conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Hu, LiWen; Wang, Fang; Gao, YanYan; Zheng, Yang; Wang, Yu; Liu, Yang

    2015-05-01

    To investigate the angular distributions of UVA, UVB, and effective UV for erythema and vitamin D (vitD) synthesis, the UV spectral irradiances were measured at ten inclined angles (from 0° to 90°) and seven azimuths (from 0° to 180°) at solar elevation angle (SEA) that ranged from 18.8° to 80° in Shanghai (31.22° N, 121.55° E) under clear sky and the albedo of ground was 0.1. The results demonstrated that in the mean azimuths and with the back to the sun, the UVA, UVB, and erythemally and vitD-weighted irradiances increased with the inclined angles and an increase in SEA. When facing toward the sun at 0°-60° inclined angles, the UVA first increased and then decreased with an increase in SEA; at other inclined angles, the UVA increased with SEA. At 0°-40° inclined angles, the UVB and erythemally and vitD-weighted irradiances first increased and then decreased with an increase in SEA, and their maximums were achieved at SEA 68.7°; at other inclined angles, the above three irradiances increased with an increase in SEA. The maximum UVA, UVB, and erythemally and vitD-weighted irradiances were achieved at an 80° inclined angle at SEA 80° (the highest in our measurements); the cumulative exposure of the half day achieved the maximum at a 60° inclined angle, but not on the horizontal. This study provides support for the assessment of human skin sun exposure.

  1. Anterior Chamber Angle Shape Analysis and Classification of Glaucoma in SS-OCT Images

    PubMed Central

    Ni Ni, Soe; Tian, J.; Marziliano, Pina; Wong, Hong-Tym

    2014-01-01

    Optical coherence tomography is a high resolution, rapid, and noninvasive diagnostic tool for angle closure glaucoma. In this paper, we present a new strategy for the classification of the angle closure glaucoma using morphological shape analysis of the iridocorneal angle. The angle structure configuration is quantified by the following six features: (1) mean of the continuous measurement of the angle opening distance; (2) area of the trapezoidal profile of the iridocorneal angle centered at Schwalbe's line; (3) mean of the iris curvature from the extracted iris image; (4) complex shape descriptor, fractal dimension, to quantify the complexity, or changes of iridocorneal angle; (5) ellipticity moment shape descriptor; and (6) triangularity moment shape descriptor. Then, the fuzzy k nearest neighbor (fkNN) classifier is utilized for classification of angle closure glaucoma. Two hundred and sixty-four swept source optical coherence tomography (SS-OCT) images from 148 patients were analyzed in this study. From the experimental results, the fkNN reveals the best classification accuracy (99.11 ± 0.76%) and AUC (0.98 ± 0.012) with the combination of fractal dimension and biometric parameters. It showed that the proposed approach has promising potential to become a computer aided diagnostic tool for angle closure glaucoma (ACG) disease. PMID:25197561

  2. Time-optimal rendezvous transfer trajectory for restricted cone-angle range solar sails

    NASA Astrophysics Data System (ADS)

    He, Jing; Gong, Sheng-Ping; Jiang, Fang-Hua; Li, Jun-Feng

    2014-10-01

    The advantage of solar sails in deep space exploration is that no fuel consumption is required. The heliocentric distance is one factor influencing the solar radiation pressure force exerted on solar sails. In addition, the solar radiation pressure force is also related to the solar sail orientation with respect to the sunlight direction. For an ideal flat solar sail, the cone angle between the sail normal and the sunlight direction determines the magnitude and direction of solar radiation pressure force. In general, the cone angle can change from 0° to 90°. However, in practical applications, a large cone angle may reduce the efficiency of solar radiation pressure force and there is a strict requirement on the attitude control. Usually, the cone angle range is restricted less more than an acute angle (for example, not more than 40°) in engineering practice. In this paper, the time-optimal transfer trajectory is designed over a restricted range of the cone angle, and an indirect method is used to solve the two point boundary value problem associated to the optimal control problem. Relevant numerical examples are provided to compare with the case of an unrestricted case, and the effects of different maximum restricted cone angles are discussed. The results indicate that (1) for the condition of a restricted cone-angle range the transfer time is longer than that for the unrestricted case and (2) the optimal transfer time increases as the maximum restricted cone angle decreases.

  3. Correlation between anatomical parameters of intertubercular sulcus and retroversion angle of humeral head

    PubMed Central

    Pan, Zhaoxun; Chen, Jun; Qu, Lianjun; Cui, Yan; Sun, Chao; Zhang, Hongxin; Yang, Xiaoming; Guan, Qingli

    2015-01-01

    Objective: To obtain anatomical data on intertubercular sulcus of humerus, evaluate the correlation between intertubercular sulcus and retroversion angle of humeral head, to guide the positioning of torsion angle of prosthesis during total shoulder arthroplasty and provide references for shoulder prosthesis design. Methods: Using a Siemens Ultrahigh speed 64- rows multi-slices spiral CT scanner and 20 dried adult humeral specimens (intact specimen, no fractures or pathological damage), of these, left lateral in 10 cases, right lateral in 10 cases, male or female all inclusive, specimens are all provided by Anatomy Department of Weifang Medical College, scan ranged from the highest point of humeral head to the distal ends of trochlea. And scanned data were subjected to statistical analysis. Results: There is a linear correlation between the distance from intertubercular sulcus to central axis line of humeral head, position angle of intertubercular sulcus and retroversion angle of humeral head at the beginning slice of intertubercular sulcus. There is a linear correlation between position angle of intertubercular sulcus and retroversion angle of humeral head at the slice of surgical neck. Conclusion: There is a linear correlation between position of intertubercular sulcus and retroversion angle of humeral head, in total shoulder arthroplasty, using intertubercular sulcus as anatomical landmark will help to accurately position torsion angle of individualized prosthesis. Position angle of intertubercular sulcus is an objective, flexible positioning indicator.

  4. Fractal Approach in Petrology: Combining Ultra-Small Angle (USANA) and Small Angle Neutron Scattering (SANS)

    SciTech Connect

    LoCelso, F.; Triolo, F.; Triolo, A.; Lin, J.S.; Lucido, G.; Triolo, R.

    1999-10-14

    Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.

  5. Flight test of the X-29A at high angle of attack: Flight dynamics and controls

    NASA Technical Reports Server (NTRS)

    Bauer, Jeffrey E.; Clarke, Robert; Burken, John J.

    1995-01-01

    The NASA Dryden Flight Research Center has flight tested two X-29A aircraft at low and high angles of attack. The high-angle-of-attack tests evaluate the feasibility of integrated X-29A technologies. More specific objectives focus on evaluating the high-angle-of-attack flying qualities, defining multiaxis controllability limits, and determining the maximum pitch-pointing capability. A pilot-selectable gain system allows examination of tradeoffs in airplane stability and maneuverability. Basic fighter maneuvers provide qualitative evaluation. Bank angle captures permit qualitative data analysis. This paper discusses the design goals and approach for high-angle-of-attack control laws and provides results from the envelope expansion and handling qualities testing at intermediate angles of attack. Comparisons of the flight test results to the predictions are made where appropriate. The pitch rate command structure of the longitudinal control system is shown to be a valid design for high-angle-of-attack control laws. Flight test results show that wing rock amplitude was overpredicted and aileron and rudder effectiveness were underpredicted. Flight tests show the X-29A airplane to be a good aircraft up to 40 deg angle of attack.

  6. Simultaneous Multi-angle Measurements of Plasma Turbulence at HAARP

    NASA Astrophysics Data System (ADS)

    Watanabe, Naomi; Golkowski, Mark; Sheerin, James; University of Colorado Denver Team

    2013-10-01

    We report the results from a recent series of experiments employing the HAARP HF transmitter to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. Diagnostics included the Modular UHF Ionospheric Radar (MUIR) located at HAARP, the Super DARN-Kodiak HF radar, and HF receivers to record stimulated electromagnetic emissions (SEE). Short pulse, low duty cycle experiments demonstrate control and suppression of artificial field-aligned irregularities (AFAI). This allows the isolation of ponderomotive plasma turbulence effects. For the first time, plasma line spectra measured simultaneously in different spots of the interaction region displayed marked but contemporaneous differences dependent on the aspect angle of the HF pump beam and the pointing angle of the MUIR diagnostic radar. Outshifted Plasma Line (OPL) spectra, rarely observed in past experiments, occurred with sufficient regularity for experimentation. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  7. An empirical study on the relation between the critical angle for bullet ricochet and the properties of wood.

    PubMed

    Kerkhoff, Wim; Alberink, Ivo; Mattijssen, Erwin J A T

    2015-05-01

    The properties of a bullet, an object, and the incidence angle determine whether the bullet will penetrate, perforate, or ricochet. In this study, the critical angle for ricochet was established for .32 Auto and 9 mm Luger bullets on Abachi, Southern Yellow Pine, Beech, and Ipe wooden boards. Results show that the critical angle differs depending on caliber and wood type. The critical angle is higher for .32 Auto bullets than for 9 mm Luger bullets and increases with increasing wood density and Janka hardness. The established critical angles for ricochet on the lightest and softest wood (Abachi) are 10.4° and 10.3° for .32 Auto and 9 mm Luger, respectively. For the heaviest and hardest wood (Ipe), the angles were 45.0° and 33.4°, respectively. The combined results on the four tested woods show a strong linear relationship between both the density and the hardness and the critical angle for both calibers. PMID:25675942

  8. MRO Mars Color Imager (MARCI) Investigation Primary Mission Results

    NASA Astrophysics Data System (ADS)

    Edgett, K. S.; Cantor, B. A.; Malin, M. C.; Science; Operations Teams, M.

    2008-12-01

    The Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI) investigation was designed to recover the wide angle camera science objectives of the Mars Climate Orbiter MARCI which was destroyed upon arrival at Mars in 1999 and extend the daily meteorological coverage of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle investigation that was systematically conducted from March 1999 to October 2006. MARCI consists of two wide angle cameras, each with a 180° field of view. The first acquires data in 5 visible wavelength channels (420, 550, 600, 650, 720 nm), the second in 2 UV channels (260, 320 nm). Data have been acquired daily, except during spacecraft upsets, since 24 September 2006. From the MRO 250 to 315 km altitude orbit, inclined 93 degrees, visible wavelength images usually have a pixel scale of about 1 km at nadir and the UV data are at about 8 km per pixel. Data are obtained during every orbit on the day side of the planet from terminator to terminator. These provide a nearly continuous record of meteorological events and changes in surface frost and albedo patterns that span more than 1 martian year and extend the daily global record of such events documented by the MGS MOC. For a few weeks in September and October 2006, both camera systems operated simultaneously, providing views of weather events at about 1400 local time (MOC) and an hour later at about 1500 (MARCI). The continuous meteorological record, now spanning more than 5 Mars years, shows very repeatable weather from year to year with cloud and dust-raising events occurring in the same regions within about 2 weeks of their prior occurrence in previous years. This provides a measure of predictability ideal for assessing future landing sites, orbiter aerobraking plans, and conditions to be encountered by the current landed spacecraft on Mars. However, less predictable are planet-encircling dust events. MOC observed one in 2001, the next was observed by MARCI in 2007. These occurred at different times of year. While popularly known as global dust storms, the nomenclature is misleading, as in each case a storm did not raise dust nor saltate sand on a global basis. Instead, multiple regional storms created a dust haze which obscured much of the martian surface from viewpoints above the lower atmosphere, but in each case the dust opacity was never so high that one could not determine where dust was being raised and where it was not. Within weeks of the end of the 2001 and 2007 global dust events, martian weather returned to its normal, repeatable pattern, with one exception: occasionally thereafter, dust storms were observed in regions where dust-raising had not been seen in the previous years. In these cases, winds capable of raising dust likely occurred at that location every year, but only became visible following a planet-encircling dust event and deposition of dust on a surface that previously did not have sufficient dust to raise. Other MARCI results center on seasonal monitoring of water vapor in the atmosphere, particularly by taking advantage of the anti-correlation between ozone (observable using the UV channels) and water vapor. Owing to their higher spatial resolution than the MOC daily global coverage, details of seasonal polar cap retreat became more apparent, as with these data it is now possible to separate surface frost from ground-hugging fog which forms along the retreating cap edge. MARCI images and meteorological observations are posted weekly on the Internet for public consumption, and the data are archived every 6 months with the NASA Planetary Data System.

  9. Multiple tests of cost-effectiveness angles.

    PubMed

    Gutjahr, G; Brannath, W

    2013-05-10

    Cost-effectiveness angles are an attractive measure of performance when comparing effects and costs of health-care therapies because they have a clear interpretation and are well suited for statistical inference. In clinical trials, a common setup is the comparison of multiple new therapies with a single control. If cost-effectiveness angles are calculated for each comparison, multiplicity issues should be taken into account when quantifying uncertainty of the point estimates. Therefore, this paper proposes a parametric test for multiple cost-effectiveness angles that guarantees strong family-wise error rate control. The idea is to replace the test of m cost-effectiveness angles as a union-intersection test of 3m linear hypotheses. Considering the correlation structure of the individual test statistics for the linear hypotheses leads to a maximum-type test for the intersection hypothesis. Inverting these test decisions then gives simultaneous CIs of cost-effectiveness angles with the appropriate coverage probabilities. PMID:22826103

  10. NORAD LOOK ANGLES AND PIO SATELLITE PACKAGE

    NASA Technical Reports Server (NTRS)

    ANONYMOUS

    1994-01-01

    This program package consists of two programs. First is the NORAD Look Angles Program, which computes satellite look angles (azimuth, elevation, and range) as well as the subsatellite points (latitude, longitude, and height). The second program in this package is the PIO Satellite Program, which computes sighting directions, visibility times, and the maximum elevation angle attained during each pass of an earth-orbiting satellite. Computations take into consideration the observing location and the effect of the earth's shadow on the satellite visibility. Input consists of a magnetic tape prepared by the NORAD Look Angles Program and punched cards containing reference Julian date, right ascension, declination, mean sidereal time at zero hours universal time of the reference date, and daily changes of these quantities. Output consists of a tabulated listing of the satellite's rise and set times, direction, and the maximum elevation angle visible from each observing location. This program has been implemented on the GE 635. The program Assembler code can easily be replaced by FORTRAN statements.

  11. Optically derived elevation angle dependence of fading for satellite PCS

    NASA Technical Reports Server (NTRS)

    Akturan, R.; Vogel, Wolf J.

    1995-01-01

    Images of urban Japan taken vertically through a 180 deg fisheye lens were analyzed to derive, as a function of elevation the fraction of sky that is clear, shadowed by trees, or blocked by buildings. At 32 deg elevation, results match those derived from satellite measurements fit to a 3-state fade model. Using the same model, for the first time the elevation angle dependence of mobile satellite fading is predicted.

  12. Low angle polarized neutron diffraction from Tb/Fe multilayers

    NASA Astrophysics Data System (ADS)

    Dufour, C.; Vergnat, M.; Cherifi, K.; Marchal, G.; Mangin, Ph.; Vettier, C.

    1992-06-01

    Low angle polarized neutron scattering experiments have been performed on a Tb(61 Å)/Fe(55Å) multilayer. The evolution of the intensities ( I+ and I-) of the first peak shows that the average magnetizations of Tb and Fe are in the applied field direction. The intensities of the second and the third peaks indicate that there is an interface effect which is going along with the terbium magnetization. It is presumably the result of the antiferromagnetic coupling between iron and terbium.

  13. Forward wide-angle light propagation in semiconductor rib waveguides.

    PubMed

    Yevick, D; Glasner, M

    1990-02-01

    We derive and examine a new nonparaxial wide-angle equation for unidirectional light propagation. We then develop a rapid unitary solution procedure utilizing both the split-step fast-Fourier-transform and finite-difference techniques. Our calculated losses for the test case of a strongly guiding semiconductor rib-waveguide Y junction are in good agreement with the results of Fresnel equation methods. PMID:19759748

  14. Angle-resolved effective potentials for disk-shaped molecules

    E-print Network

    Thomas Heinemann; Karol Palczynski; Joachim Dzubiella; Sabine H. L. Klapp

    2014-10-22

    We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van-der-Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.

  15. Experiment of ~200 keV electron pitch angle diffusion near loss cone boundary.

    NASA Astrophysics Data System (ADS)

    Lee, J.

    2014-12-01

    In this presentation, we show the ~200 keV electron pitch angle distribution near loss cone boundary and derive the minimum pitch angle diffusion coefficients calculated from the observation. Solid-state detectors aboard low altitude satellite, STSAT-1, were used for the measurements of the electron energy spectra. In order to measure the pitch angle distribution, we rotated the satellite's attitude about 90° with respect to the geomagnetic field line. The results show sharp boundary at the loss cone angle of 55°. To demonstrate the pitch angle distribution, we simulated drift loss and diffusion effect for longitude by solving the diffusion equation. While the pitch angle distribution measurements were performed at the altitude of 700 km, latitude of 70° and longitude of 130°E, the drift electrons are lost in the SAA region. Accordingly, the observed electrons are results of pitch angle diffusion from loss cone boundary and we can estimate minimum diffusion coefficient. In our model, the pitch angle diffusion coefficient should be larger than 1.0x105 rad2/sec

  16. Simultaneous Multi-angle Observations of Strong Langmuir Turbulence at HAARP

    NASA Astrophysics Data System (ADS)

    Watanabe, Naomi; Golkowski, Mark; Sheerin, James P.; Watkins, Brenton J.

    2015-06-01

    We report results from a recent series of experiments employing the HF transmitter of the High Frequency Active Auroral Research Program (HAARP) to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. The Modular UHF Ionospheric Radar (MUIR) located at the HAARP facility is used as the primary diagnostic. Short pulse, low duty cycle experiments are used to avoid generation of artificial field-aligned irregularities and isolate ponderomotive plasma turbulence effects. The HF pump frequency is close to the 3rd gyro-harmonic frequency and the HF pointing angle and MUIR look angle are between the HF Spitze angle and Magnetic Zenith angle. Plasma line spectra measured simultaneously in different spots of the interaction region display differences dependent on the aspect angle of the HF pump beam in the boresight direction and the pointing angle of the MUIR diagnostic radar. Outshifted Plasma Lines, cascade, collapse, coexistence, spectra are observed in agreement with existing theory and simulation results of Strong Langmuir Turbulence in ionospheric interaction experiments. It is found that SLT at HAARP is most readily observed at a HF pointing angle of 11° and UHF observation angle of 15°, which is consistent with the magnetic zenith effect as documented in previous works and optimal orientation of the refracted HF electric field vector.

  17. A heterodyne interferometer for angle metrology.

    PubMed

    Hahn, Inseob; Weilert, M; Wang, X; Goullioud, R

    2010-04-01

    We have developed a compact, high-resolution, angle measurement instrument based on a heterodyne interferometer. Common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer set up, an optical mask is used to sample the laser beam reflecting back from four areas on a target surface. From the relative displacement measurements of the target surface areas, we can simultaneously determine angular rotations around two orthogonal axes in a plane perpendicular to the measurement beam propagation direction. The device is used in a testbed for a tracking telescope system where pitch and yaw angle measurements of a flat mirror are performed. Angle noise measurement of the device shows 0.1 nrad/square root of Hz at 1 Hz, at a working distance of 1 m. The operation range and nonlinearity of the device when used with a flat mirror is approximately +/-0.15 mrad, and 3 microrad rms, respectively. PMID:20441364

  18. Angle-averaged Compton cross sections

    SciTech Connect

    Nickel, G.H.

    1983-01-01

    The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.

  19. High brightness angled cavity quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Heydari, D.; Bai, Y.; Bandyopadhyay, N.; Slivken, S.; Razeghi, M.

    2015-03-01

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 ?m, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 ?m. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm-2 sr-1 is obtained, which marks the brightest QCL to date.

  20. Effect of variation in seat tube angle at different seat heights on submaximal cycling performance in man.

    PubMed

    Price, D; Donne, B

    1997-08-01

    The effect of seat tube angle at selected seat heights (96, 100 and 104% trochanteric height) on heart rate, VO2 and lower limb kinematics was evaluated in 14 competitive male road racing cyclists during discontinuous submaximal exercise (200 W) on an air-resistance ergometer at seat tube angles of 68, 74 and 80 degrees. The tests were randomized to complete the nine combinations (three seat heights, three tube angles) in opposite directions from a starting tube angle of 74 degrees and 100% trochanteric height to avoid any time or sequence bias. Power efficiency was calculated for each combination from work done and VO2. All results were analysed using ANOVA for repeated measures. At a seat tube angle of 80 degrees, mean VO2 was significantly lower and power efficiency significantly higher compared with an angle of 74 degrees at all three seat heights, while heart rate was significantly lower only at a seat height equal to trochanteric height. At a seat tube angle of 74 degrees, mean VO2 and heart rate were significantly lower and power efficiency significantly higher compared with an angle of 68 degrees at all three seat heights. Hip range of movement and maximum and minimum hip angle were significantly less at an angle of 80 degrees compared with 68 degrees. Further biomechanical analysis suggested that the improvement in cycling efficiency observed at steeper seat tube angles was produced in part by the resultant altered ankling pattern of the cyclist. PMID:9293416

  1. Ship wakes: Kelvin or Mach angle?

    E-print Network

    Rabaud, Marc

    2013-01-01

    From the analysis of a set of airborne images of ship wakes, we show that the wake angles decrease as $U^{-1}$ at large velocities, in a way similar to the Mach cone for supersonic airplanes. This previously unnoticed Mach-like regime is in contradiction with the celebrated Kelvin prediction of a constant angle of $19.47\\degree$ independent of the ship's speed. We propose here a model, confirmed by numerical simulations, in which the finite size of the disturbance explains this transition between the Kelvin and Mach regimes at a Froude number $Fr = U/\\sqrt{gL} \\simeq 0.5$, where $L$ is the hull ship length.

  2. Optimization of Wind Farm Performance Based on Yaw Angle Control

    NASA Astrophysics Data System (ADS)

    Bastankhah, Majid; Porté-Agel, Fernando; Dios Romero, Isabel

    2014-05-01

    Inside wind farms, the wakes of upwind turbines result in a significant reduction in power production. Yawing upwind turbines can be used to deflect the wakes away from turbines. Even though this reduces the power production of upwind turbines, it can potentially result in increasing the power production of the whole wind farm. The present work aims to investigate the possibility of improving the performance of wind farms by controlling the yaw angle of turbines. In this regard, wind-tunnel experiments were carried out to study the wake interactions of model turbines and their performance at different yaw angles and different layout configurations. First, it is observed that the power production of the two model turbines, located in a line parallel to the wind, is not considerably improved by yawing the first one. Next, the effect of yaw angle on the performance of a row of ten model turbines parallel to the wind flow, leading to full-wake conditions, was studied. Two configurations were considered: (a) turbines are yawed to the same direction with respect to the wind flow, and (b) each two consecutive turbines are yawed to different directions. The first configuration is found to have a better performance in terms of power production, whereas fatigue loads are lower in the second one. In the first configuration, the best power production is observed when the first turbine has a large yaw angle, and it progressively decreases for the next turbines. Yaw angle control was also considered for the case that turbines are located in partial-wake conditions. These conditions, which commonly occur in real-scale wind farms, are achieved in the wind tunnel by shifting the downwind turbines laterally with respect to the first turbine. In this case, not only can yawing upwind turbines potentially increase the power production of wind farms, but also it can decrease the fatigue loads on downwind turbines by totally deflecting the wake away from them. In general, it is found that the control of the yaw angle in this situation can significantly improve the power even for just two turbines, unlike the case in which the wind flow is exactly parallel to the row of turbines.

  3. What's my angle? : do people with big hands have larger angles between their fingers?

    NSDL National Science Digital Library

    National Action Council for Minorities in Engineering

    2002-01-01

    This activity challenges students to think about angles as geometric shapes and to find the sizes of the angles between their fingers. It is part of the Figure This! collection of 80 online mathematical challenges emphasizing real world uses of mathematics. For this challenge, the students trace a hand stretched to form an L-shape with the thumb and sketches angles of 90 degrees and 45 degrees between the thumb and index finger. They use the sketches to estimate the angles between their other fingers. Questions extend the challenge to finding the distance a bike wheel travels in one rotation, the headings of compass directions, and the number of degrees between the hands of a clock. Also included are directions for making a protractor by folding a circle of paper and a question about the meaning of negative angles. Copyright 2005 Eisenhower National Clearinghouse

  4. Characterizing the combinatorial beam angle selection problem

    NASA Astrophysics Data System (ADS)

    Bangert, Mark; Ziegenhein, Peter; Oelfke, Uwe

    2012-10-01

    The beam angle selection (BAS) problem in intensity-modulated radiation therapy is often interpreted as a combinatorial optimization problem, i.e. finding the best combination of ? beams in a discrete set of candidate beams. It is well established that the combinatorial BAS problem may be solved efficiently with metaheuristics such as simulated annealing or genetic algorithms. However, the underlying parameters of the optimization process, such as the inclusion of non-coplanar candidate beams, the angular resolution in the space of candidate beams, and the number of evaluated beam ensembles as well as the relative performance of different metaheuristics have not yet been systematically investigated. We study these open questions in a meta-analysis of four strategies for combinatorial optimization in order to provide a reference for future research related to the BAS problem in intensity-modulated radiation therapy treatment planning. We introduce a high-performance inverse planning engine for BAS. It performs a full fluence optimization for ?3600 treatment plans per hour while handling up to 50?GB of dose influence data (?1400 candidate beams). For three head and neck patients, we compare the relative performance of a genetic, a cross-entropy, a simulated annealing and a naive iterative algorithm. The selection of ensembles with 5, 7, 9 and 11 beams considering either only coplanar or all feasible candidate beams is studied for an angular resolution of 5°, 10°, 15° and 20° in the space of candidate beams. The impact of different convergence criteria is investigated in comparison to a fixed termination after the evaluation of 10?000 beam ensembles. In total, our simulations comprise a full fluence optimization for about 3000?000 treatment plans. All four combinatorial BAS strategies yield significant improvements of the objective function value and of the corresponding dose distributions compared to standard beam configurations with equi-spaced coplanar beams. The genetic and the cross-entropy algorithms showed faster convergence in the very beginning of the optimization but the simulated annealing algorithm eventually arrived at almost the same objective function values. These three strategies typically yield clinically equivalent treatment plans. The iterative algorithm showed the worst convergence properties. The choice of the termination criterion had a stronger influence on the performance of the simulated annealing algorithm than on the performance of the genetic and the cross-entropy algorithms. We advocate to terminate the optimization process after the evaluation of 1000 beam combinations without objective function decrease. For our simulations, this resulted in an average deviation of the objective function from the reference value after 10?000 evaluated beam ensembles of 0.5% for all metaheuristics. On average, there was only a minor improvement when increasing the angular resolution in the space of candidate beam angles from 20° to 5°. However, we observed significant improvements when considering non-coplanar candidate beams for challenging head and neck cases.

  5. Wide-angle breast tomosynthesis: initial comparative evaluation

    NASA Astrophysics Data System (ADS)

    Thompson, John; Chen, Baiyu; Richard, Samuel; Bowsher, James; Samei, Ehsan

    2010-04-01

    Conventional mammography is largely limited by superimposed anatomy which is alleviated by breast tomosynthesis and CT. Limited acquisition in tomosynthesis can result in significant out of plane artifacts while large angular acquisition span in CT can limit the imaging coverage of the chest wall near the breast. We propose a new breast imaging modality, wide-angle breast tomosynthesis (WBT), aimed to provide a practical compromise between 3D sampling and chest-wall coverage. This study compares lesion detection between conventional digital breast tomosynthesis, WBT, and breast CT (44°, 99°, and 198° total angle range, respectively) under equal patient dose conditions. A Monte Carlo (MC) code based on the Penelope package modeled a virtual flat-panel breast tomosynthesis system. The modalities were simulated at four breast compression levels. Glandular dose to the breast was estimated and the radiation flux was subsequently adjusted to achieve a constant mean glandular dose level of 1.5 mGy, independent of the breast thickness and acquisition geometry. Reconstructed volumes were generated using iterative reconstruction methods. Lesion detectability was estimated using contrast-to-noise-ratio. Results showed improved detection with increased angular span and compression. Evaluations also showed improved performance of WBT over DBT at lower compression levels, therefore highlighting potential for reduced breast compression when using a larger acquisition angle.

  6. View Angle Effects on MODIS Snow Mapping in Forests

    NASA Technical Reports Server (NTRS)

    Xin, Qinchuan; Woodcock, Curtis E.; Liu, Jicheng; Tan, Bin; Melloh, Rae A.; Davis, Robert E.

    2012-01-01

    Binary snow maps and fractional snow cover data are provided routinely from MODIS (Moderate Resolution Imaging Spectroradiometer). This paper investigates how the wide observation angles of MODIS influence the current snow mapping algorithm in forested areas. Theoretical modeling results indicate that large view zenith angles (VZA) can lead to underestimation of fractional snow cover (FSC) by reducing the amount of the ground surface that is viewable through forest canopies, and by increasing uncertainties during the gridding of MODIS data. At the end of the MODIS scan line, the total modeled error can be as much as 50% for FSC. Empirical analysis of MODIS/Terra snow products in four forest sites shows high fluctuation in FSC estimates on consecutive days. In addition, the normalized difference snow index (NDSI) values, which are the primary input to the MODIS snow mapping algorithms, decrease as VZA increases at the site level. At the pixel level, NDSI values have higher variances, and are correlated with the normalized difference vegetation index (NDVI) in snow covered forests. These findings are consistent with our modeled results, and imply that consideration of view angle effects could improve MODIS snow monitoring in forested areas.

  7. A Study on Estimating the Aiming Angle Error of Millimeter Wave Radar for Automobile

    NASA Astrophysics Data System (ADS)

    Kuroda, Hiroshi; Okai, Fumihiko; Takano, Kazuaki

    The 76GHz millimeter wave radar has been developed for automotive application such as ACC (Adaptive Cruise Control) and CWS (Collision Warning System). The radar is FSK (Frequency Shift Keying) monopulse type. The radar transmits 2 frequencies in time-duplex manner, and measures distance and relative speed of targets. The monopulse feature detects the azimuth angle of targets without a scanning mechanism. Conventionally a radar unit is aimed mechanically, although self-aiming capability, to detect and correct the aiming angle error automatically, has been required. The new algorithm, which estimates the aiming angle error and vehicle speed sensor error simultaneously, has been proposed and tested. The algorithm is based on the relationship of relative speed and azimuth angle of stationary objects, and the least squares method is used for calculation. The algorithm is applied to measured data of the millimeter wave radar, resulting in aiming angle estimation error of less than 0.6 degree.

  8. Numerical investigation of cone angle effect on the flow field and separation efficiency of deoiling hydrocyclones

    NASA Astrophysics Data System (ADS)

    Saidi, Maysam; Maddahian, Reza; Farhanieh, Bijan

    2013-02-01

    In this study, the effect of cone angle on the flow field and separation efficiency of deoiling hydrocyclones is investigated taking advantage of large eddy simulation. The dynamic Smagorinsky is employed to determine the residual stress tensor of the continuous phase. The method of Lagrangian particle tracking with an optimized search algorithm (closest cell) is applied to evaluate the separation efficiency of deoiling hydrocyclone. Simulations are performed on a 35-mm deoiling hydrocyclone with the three different cone angles of 6, 10 and 20 degree. The numerical results revealed that the changes in the cone angle would affect the velocity and pressure distribution inside hydrocyclone, and lead to changes in the separation efficiency. However, the large cone angle increases the tangential velocity and pressure gradient inside the hydrocyclone, but reduces the separation efficiency. The reasons behind the decrease in the separation efficiency are the flow structure and reduction of oil droplets residence time in hydrocyclones with large cone angles.

  9. Effect of combined roll rate and sideslip angle on aircraft flight stability

    NASA Technical Reports Server (NTRS)

    Stengel, R. F.

    1975-01-01

    The combined destabilizing effects of roll rate and sideslip angle are studied for a high angle-of-attack flight condition using a linear simulation of the coupled motions of a Space Shuttle-like configuration. Variations in the eigenvalues for a flight condition nominally identified by an angle of attack of 33.29 deg and a Mach number of 4.9 are examined with illustrations of the separate effects of body-axis roll rate and yaw rate, stability-axis roll rate, dynamic pressure, and sideslip angle. It is shown that the stability of the free motion of the vehicle is sensitive to roll rate and that this sensitivity is enhanced by nonzero sideslip angle. The results suggest that fully coupled linearized equations can be of value both for the study of Space Shuttle stability and for a better understanding of post-stall gyrations, incipient spin, and departure prevention for high-performance aircraft.

  10. Compact Multilayer Film Structure for Angle Insensitive Color Filtering

    NASA Astrophysics Data System (ADS)

    Yang, Chenying; Shen, Weidong; Zhang, Yueguang; Li, Kan; Fang, Xu; Zhang, Xing; Liu, Xu

    2015-03-01

    Here we report a compact multilayer film structure for angle robust color filtering, which is verified by theoretical calculations and experiment results. The introduction of the amorphous silicon in the proposed unsymmetrical resonant cavity greatly reduces the angular sensitivity of the filters, which is confirmed by the analysis of the phase shift within the structure. The temperature of the substrate during the deposition is expressly investigated to obtain the best optical performance with high peak reflectance and good angle insensitive color filtering by compromising the refractive index of dielectric layer and the surface roughness of the multilayer film. And the outlayer of the structure, worked as the anti-reflection layer, have an enormous impact on the filtering performance. This method, described in this paper, can have enormous potential for diverse applications in display, colorful decoration, anti-counterfeiting and so forth.

  11. Shallow-angle water entry of ballistic projectiles

    NASA Astrophysics Data System (ADS)

    Truscott, Tadd T.; Gomez, Jason T.; Beal, David N.; Techet, Alexandra H.

    2008-11-01

    The water-entry of ballistic projectiles is investigated using high-speed digital imaging. Projectiles enter the water at shallow angles to the free surface, 5^o-15^o, without ricochet at Mach numbers between 0.3 and 2.0. Projectile dynamics, critical entry angle, and cavity growth are discussed. Geometric modifications to a projectile allow it to travel large distances underwater assuming a sufficiently large air-cavity is formed after impact, which dramatically decreases drag on the projectile. Results show that successful water-entry occurs for projectiles with modified tip geometries at Mach numbers ranging from 0.3 to 2; these projectile modifications include tip geometry and material properties. A theoretical cavity model compares well with the experimental data and will be discussed for a range of experimental conditions.

  12. The Turbulent Flow in Diffusers of Small Divergence Angle

    NASA Technical Reports Server (NTRS)

    Gourzhienko, G. A.

    1947-01-01

    The turbulent flow in a conical diffuser represents the type of turbulent boundary layer with positive longitudinal pressure gradient. In contrast to the boundary layer problem, however, it is not necessary that the pressure distribution along the limits of the boundary layer(along the axis of the diffuser) be given, since this distribution can be obtained from the computation. This circumstance, together with the greater simplicity of the problem as a whole, provides a useful basis for the study of the extension of the results of semiempirical theories to the case of motion with a positive pressure gradient. In the first part of the paper,formulas are derived for the computation of the velocity and.pressure distributions in the turbulent flow along, and at right angles to, the axis of a diffuser of small cone angle. The problem is solved.

  13. Discharge coefficients of holes angled to the flow direction

    NASA Astrophysics Data System (ADS)

    Hay, N.; Henshall, S. E.; Manning, A.

    1992-06-01

    In the cooling passages of gas turbine blades, branches are often angled to the direction of the internal flow. This is particularly the case with film cooling holes. Accurate knowledge of the discharge coefficient of such holes at the design stage is vital so that the holes are correctly sized thus avoiding wastage of coolant and the formation of hot spots on the blade. This paper describes an experimental investigation to determine the discharge coefficient of 30 deg inclined holes with various degrees of inlet radiusing and with the axis of the hole at various orientation angles to the direction of the flow. Results are given for nominal main flow Mach numbers of 0, 0.15 and 0.3. The effects of radiusing, orientation and cross flow Mach number are quantified in the paper, the general trends are described, and the criteria for optimum performance are identified.

  14. Searching for the Neutrino Mixing Angle Theta-13 at Reactors

    E-print Network

    Maury Goodman

    2007-06-04

    Two neutrino mixing angles have been measured, and much of the neutrino community is turning its attention to the unmeasured mixing angle, $\\quq$, whose best limit comes from the reactor neutrino experiment CHOOZ.\\cite{bib:chooz} New two detector reactor neutrino experiments are being planned, along with more ambitious accelerator experiments, to measure or further limit $\\quq$. Here I will overview how to measure $\\quq$ using reactor neutrinos, mention some experiments that were considered and are not going forward, and review the current status of four projects: Double Chooz in France, Daya Bay in China, RENO in South Korea and Angra in Brazil. Finally I will mention how the neutrino observer can gauge progress in these projects two years from now as we approach the times corresponding to early estimates for new results.

  15. Cardinality bounds for triangulations with bounded minimum angle

    SciTech Connect

    Mitchell, S.A.

    1994-05-01

    We consider bounding the cardinality of an arbitrary triangulation with smallest angle {alpha}. We show that if the local feature size (i.e. distance between disjoint vertices or edges) of the triangulation is within a constant factor of the local feature size of the input, then N < O(1/{alpha})M, where N is the cardinality of the triangulation and M is the cardinality of any other triangulation with smallest angle at least {alpha}. Previous results had an O(1/{alpha}{sup 1/{alpha}}) dependence. Our O(1/{alpha}) dependence is tight for input with a large length to height ratio, in which triangles may be oriented along the long dimension.

  16. Effects of Hierarchical Surface Roughness on Droplet Contact Angle.

    PubMed

    Bell, Michael S; Shahraz, Azar; Fichthorn, Kristen A; Borhan, Ali

    2015-06-23

    Superhydrophobic surfaces often incorporate roughness on both micron and nanometer length scales, although a satisfactory understanding of the role of this hierarchical roughness in causing superhydrophobicity remains elusive. We present a two-dimensional thermodynamic model to describe wetting on hierarchically grooved surfaces by droplets for which the influence of gravity is negligible. By creating wetting phase diagrams for droplets on surfaces with both single-scale and hierarchical roughness, we find that hierarchical roughness leads to greatly expanded superhydrophobic domains in phase space over those for a single scale of roughness. Our results indicate that an important role of the nanoscale roughness is to increase the effective Young's angle of the microscale features, leading to smaller required aspect ratios (height to width) for the surface structures. We then show how this idea may be used to design a hierarchically rough surface with optimally high contact angles. PMID:26030089

  17. Variation of attenuation and space diversity with elevation angle on 12 GHz satellite-to-ground radio paths

    Microsoft Academic Search

    J. E. Allnutt

    1977-01-01

    The results of a 6-deg-elevation-angle space-diversity experiment at a frequency of 11.6 GHz are reported, and is a comparison made with earlier results obtained by using the same sites at an elevation angle of 29.5 deg. For a given percentage time, more than double the path attenuation was measured at the lower elevation angle. Methods of predicting the attenuation and

  18. NEUTRINO SCATTERING IN PERTURBATIVE QCD AND IMPLICATIONS FOR THE WEINBERG ANGLE.

    SciTech Connect

    KRETZER,S.HALL-RENO,M.

    2003-05-19

    We summarize a recent calculation of perturbative neutrino cross sections that includes NLO and mass corrections. We provide numerical results for quantities that are related to the extraction of the weak mixing angle from neutrino deep inelastic scattering.

  19. Attitude control for large angle maneuvers

    Microsoft Academic Search

    A. Cavallo; G. De Maria

    1996-01-01

    A sliding manifold based control strategy is proposed for the attitude control problem. By using the theory of singular perturbation and the globally nonsingular unit quaternion representation for the orientation error a nonlinear feedback control is designed. The use of quaternions allows us to avoid the drawbacks of Euler angle approach, namely singularities which can occur in large maneuvers. The

  20. Shallow angle LIDAR for wave measurement

    Microsoft Academic Search

    J. M. K. Horwood; R. W. F. Thurley; M. R. Belmont; J. Baker

    2005-01-01

    The Exeter University Marine Dynamics Group has developed a shallow angle LIDAR for wave measurement purposes. This paper introduces the system and illustrates some metrology issues specific to this method. The LIDAR system uses a 532 nm (green) Q switched, high repetition rate, nanosecond pulsed laser. The system is designed to be scanned along a line or over an area.

  1. Boiler Efficiency--Consider All the Angles

    E-print Network

    Blakeley, C. P.

    1981-01-01

    BOILER EFFICIENCY--CONSIDER ALL THE ANGLES Christopher P. Blakeley Honeywell r>rocess !lanagement Systems Division Fort Washington, Pennsylvania The cost of steam has become a very real part of Product cost. U.S.lndustry strives to become more...

  2. Fermi acceleration and particle pitch angle scattering

    Microsoft Academic Search

    J. S. Scott; D. G. Wentzel; W. J. Cocke; R. A. Chevalier

    1978-01-01

    The effect of particle streaming instability on Fermi acceleration is investigated. When velocity gradients in a nearly collisionless plasma are sharp, the gain time for relativistic particles is comparable to that obtained in the absence of pitch-angle scattering. Such an observation leads to the conclusion that Fermi acceleration of thermal particles is quenched, but the Fermi acceleration coefficient for relativistic

  3. Points, Lines, and Angles, Oh My!

    NSDL National Science Digital Library

    victoria pease

    2012-08-02

    In this lesson, students work to identify points, lines, line segments, rays, angles and perpendicular and parallel lines. Students create webs of yarn and analyze the web for geometric properties listed above. Students also work with pattern blocks to gain experience.

  4. Acute Angle Closure Glaucoma with Capilllary Leak Syndrome Following Snake Bite

    PubMed Central

    George, Twinkle Ann; AV, Asha; Ravindran, Risha

    2014-01-01

    Introduction: Acute angle closure glaucoma is rarely seen as complication of snake bite.We report three cases of bilateral acute angle closure glaucoma with capillary leak syndrome and acute renal failure secondary to hematotoxic snake bites. We are also briefly discussing the association of capillary leak syndrome and angle closure glaucoma in hematotoxic snake bite. This is the first time an association between angle closure and capillary leak syndrome following snake bite is reported. Study type: Descriptive case series. Materials and Methods: Records of all patients admitted to ICU with snake bite were reviewed to identify cases developing acute angle closure glaucoma. These cases with acute angle closure glaucoma are analysed in detail for systemic condition. Diagnosis, management and outcome of cases are described Results: Of the 119 snake bites admitted, 47 patients had confirmed hematotoxic snake bite. Fifteen of these patients underwent hemodialysis for acute renal failure. Seven of them were diagnosed to have capillary leak syndrome and all of them complained of decreased vision. Three of the 7 cases had acute angle closure glaucoma on the second day of bite. One of the patients expired and other two recovered fully, both of them had normal IOP and good vision at one month follow-up. Conclusion: Acute angle closure glaucoma seems to be associated with systemic capillary leak syndrome in hematotoxic snake bite. High suspicion, early recognition, timely and appropriate treatment can prevent visual loss in this rare complication. PMID:25478432

  5. Age-related Changes in Maximum Pelvic Anteversion and Retroversion Angles Measured in the Sitting Position.

    PubMed

    Asai, Hitoshi; Tsuchiyama, Hiroyuki; Hatakeyama, Tomoyuki; Inaoka, Pleiades Tiharu; Murata, Kanichirou

    2014-12-01

    [Purpose] The purpose of this study was to investigate the relationship between age and the maximum pelvic anteversion and retroversion angles, as well as the associated pelvic range of motion, measured in a sitting position with free knee movement. [Subjects] A total of 132 healthy volunteers (74 women, 58 men; age range, 20-79 years) were divided into six groups based on age (20-29, 30-39, 40-49, 50-59, 60-69, and 70-79 years). [Methods] The maximum pelvic anteversion and retroversion angles were measured manually five times by a goniometer in a sitting position that allowed free movement of the knee joints. [Results] There was a significant effect of age group on the maximum pelvic anteversion and retroversion angles and pelvic range of motion (the difference between these angles). There was a significant correlation between age and the maximum pelvic anteversion angle, maximum pelvic retroversion angle, and pelvic range of motion. [Conclusion] The maximum pelvic anteversion and retroversion angles and pelvic range of motion were significantly correlated with age. The maximum pelvic anteversion angle and pelvic range of motion were most affected by age. PMID:25540507

  6. Gantry-angle resolved VMAT pretreatment verification using EPID image prediction

    SciTech Connect

    Woodruff, Henry C.; Rowshanfarzad, Pejman [School of Mathematical and Physical Sciences, The University of Newcastle, NSW 2308 (Australia)] [School of Mathematical and Physical Sciences, The University of Newcastle, NSW 2308 (Australia); Fuangrod, Todsaporn [School of Electrical Engineering and Computer Science, The University of Newcastle, NSW 2308 (Australia)] [School of Electrical Engineering and Computer Science, The University of Newcastle, NSW 2308 (Australia); McCurdy, Boyd M. C. [Division of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada) [Division of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Department of Radiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Greer, Peter B. [School of Mathematical and Physical Sciences, The University of Newcastle, NSW 2308, Australia and Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Locked Bag 7, Hunter region Mail Centre, Newcastle, NSW 2310 (Australia)] [School of Mathematical and Physical Sciences, The University of Newcastle, NSW 2308, Australia and Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Locked Bag 7, Hunter region Mail Centre, Newcastle, NSW 2310 (Australia)

    2013-08-15

    Purpose: Pretreatment verification of volumetric modulated arc therapy (VMAT) dose delivery with electronic portal imaging device (EPID) uses images integrated over the entire delivery or over large subarcs. This work aims to develop a new method for gantry-angle-resolved verification of VMAT dose delivery using EPID.Methods: An EPID dose prediction model was used to calculate EPID images as a function of gantry angle for eight prostate patient deliveries. EPID image frames at 7.5 frames per second were acquired during delivery via a frame-grabber system. The gantry angle for each image was encoded in kV frames which were synchronized to the MV frames. Gamma analysis results as a function of gantry angle were assessed by integrating the frames over 2° subarcs with an angle-to-agreement tolerance of 0.5° about the measured image angle.Results: The model agreed with EPID images integrated over the entire delivery with average Gamma pass-rates at 2%, 2 mm of 99.7% (10% threshold). The accuracy of the kV derived gantry angle for each image was found to be 0.1° (1 SD) using a phantom test. For the gantry-resolved analysis all Gamma pass-rates were greater than 90% at 3%, 3 mm criteria (with only two exceptions), and more than 90% had a 95% pass-rate, with an average of 97.3%. The measured gantry angle lagged behind the predicted angle by a mean of 0.3°± 0.3°, with a maximum lag of 1.3°.Conclusions: The method provides a comprehensive and highly efficient pretreatment verification of VMAT delivery using EPID. Dose delivery accuracy is assessed as a function of gantry angle to ensure accurate treatment.

  7. Seismic Slip on an Oblique Detachment Fault at Low Angles

    NASA Astrophysics Data System (ADS)

    Janecke, S. U.; Steely, A. N.; Evans, J. P.

    2008-12-01

    Pseudotachylytes are one of the few accepted indicators of seismic slip along ancient faults. Low-angle normal faults have produced few large earthquakes in historic times and low-angle normal faults (detachment faults) are typically severely misoriented relative to a vertical maximum compressive stress. As a result many geoscientists question whether low-angle normal faults produce earthquakes at low angles. Relationships in southern California show that a major low-angle normal-oblique fault slipped at low angles and produced large earthquakes. The exhumed Late Cenozoic West Salton detachment fault preserves spectacular fault- related pseudotachylytes along its fault plane and injected into its hanging wall and footwall. Composite pseudotachylyte zones are up to 1.25 m thick and persists over lateral distances of at least 10's of meters. Pseudotachylyte is common in most thin sections of damaged fault rocks with more than 20% (by volume) of cataclasite. We recognized the presence of original melt using numerous criteria: abundant spherulites in thin sections, injection structures at both the thin-section and outcrop scale, black aphanitic textures, quenched vein margins, variations in microcrystallite textures and/or size with respect to the vein margin, and glassy textures in hand sample. Multiple earthquakes are inferred to produce the layered "stratigraphy" in some exposures of pseudotachylytes. We infer that the West Salton detachment fault formed and slipped at low angles because it nearly perfectly reactivates a Cretaceous ductile thrust system at the half km scale and dips between 10 and 45 degrees. The about 30 degree NNE dip of the detachment fault on the north side of Yaqui Ridge is likely steeper than its dip during detachment slip because there is local steepening on the flanks of the Yaqui Ridge antiform in a contractional stepover of a crosscutting Quaternary San Felipe dextral fault zone. These relationships indicate a low dip on the detachment fault when the detachment was active, when it produced voluminous pseudotachylyte during eartquakes, and when the supradetachment basin above it received a large volume of sediment eroded from the pseudotachylyte-bearing parts of the damage zone. To interpret the pseudotachylyte as the product of slip across a detachment when it was dipping at least 45 degrees requires a sequence of events that is so unlikely that we reject it. There must have been seismic slip at low dip angles across the West Salton detachment fault. Our conclusion agrees with prior studies by John and Axen in the Chemehuevi and Whipple metamorphic core complex and increases the published catalogue of detachment faults that sport pseudotachylytes. These data document that low-angle normal faults are seismogenic, and that conditions that allow pseudotachylytes to form may occur at shallow levels in the crust.

  8. An Application of Ptolemy's Theorem:Integral triangles with a 120 degree angle and the bisector(of the 120degree angle)also of integral length

    E-print Network

    Zelator, Konstantine

    2012-01-01

    In one of the three 2010/2011 issues of the journal 'MathematicalSpectrum', this author gave a three-parameter description of the entire set of integral triangles(i.e. triangles with integer side lengths)and with a 120 degree angle.This entire set expressed as a union of four families, see reference[5]. In this work we describe, in terms of three parameters again, the set of all integral with a 120 degree angle, and whose bisectors of their 120 degree angles; is also of integral length. To do so, we use the well known historic theorem of Ptolemy for cyclic quadrilaterals, in conjunction with the general positive integer solution of the equation, 1/z=1/x +1/y; and of course in combination with the parametric description of the set of integral triangles with a 120 degree angle mentioned above,The final results of this paper are found in section8.

  9. Relationship of Q angle and joint hypermobility and Q angle values in different positions.

    PubMed

    Sendur, Omer Faruk; Gurer, Gulcan; Yildirim, Tuncay; Ozturk, Emine; Aydeniz, Ali

    2006-05-01

    Patellar malalignment is the most important reason for anterior knee pain. Patellar alignment is commonly determined by the measurement of the quadriceps (Q) angle. In this study, our primary aim was to investigate the Q angle difference between healthy individuals with and without joint hypermobility. The other objectives were to compare the Q angle values, which were measured in supine and upright positions, to determine hypermobility frequency among healthy males in a certain population, and to investigate the correlation between the existent skeletal deformities and Beighton score levels. Two hundred fifty-three healthy male college students were examined for hypermobility and skeletal deformities. According to the Beighton scoring system, three groups (n=20) were formed, and Q angle measurements were performed on the 60 individuals in both supine and upright positions. In the comparison of the groups, the mean Q angle values in healthy hypermobile individuals were found to be significantly higher than that of the nonhypermobile ones (p<0.05). No statistical difference was found between Q angle values in supine and upright positions (p>0.05). The frequency of joint hypermobility (Beighton score 4 or more) was found to be 29.25% in this population. No correlation was determined between existent skeletal deformities and Beighton score values (p>0.05). In conclusion, the Q angle evaluation among healthy hypermobile individuals may have a prognostic value for probable knee pathologies that may appear in the future. PMID:16208428

  10. Material loss angles from direct measurements of broadband thermal noise

    E-print Network

    Principe, Maria; Pierro, Vincenzo; DeSalvo, Riccardo; Taurasi, Ilaria; Villar, Akira E; Black, Eric D; Libbrecht, Kenneth G; Michel, Christophe; Morgado, Nazario; Pinard, Laurent

    2015-01-01

    We estimate the loss angles of the materials currently used in the highly reflective test-mass coatings of interferometric detectors of gravitational waves, namely Silica, Tantala, and Ti-dop ed Tantala, from direct measurement of coating thermal noise in an optical interferometer testbench, the Caltech TNI. We also present a simple predictive theory for the material properties of amorphous glassy oxide mixtures, which gives results in good agreement with our measurements on Ti-doped Tantala. Alternative measure ment methods and results are reviewed, and some critical issues are discussed.

  11. Material loss angles from direct measurements of broadband thermal noise

    NASA Astrophysics Data System (ADS)

    Principe, Maria; Pinto, Innocenzo M.; Pierro, Vincenzo; DeSalvo, Riccardo; Taurasi, Ilaria; Villar, Akira E.; Black, Eric D.; Libbrecht, Kenneth G.; Michel, Christophe; Morgado, Nazario; Pinard, Laurent

    2015-01-01

    We estimate the loss angles of the materials currently used in the highly reflective test-mass coatings of interferometric detectors of gravitational waves, namely Silica, Tantala, and Ti-doped Tantala, from direct measurement of coating thermal noise in an optical interferometer testbench, the Caltech TNI. We also present a simple predictive theory for the material properties of amorphous glassy oxide mixtures, which gives results in good agreement with our measurements on Ti-doped Tantala. Alternative measurement methods and results are reviewed, and some critical issues are discussed.

  12. A high angle of attack inviscid shuttle orbiter computation

    NASA Technical Reports Server (NTRS)

    Kleb, William L.; Weilmuenster, K. James

    1992-01-01

    As a preliminary step toward predicting the leeside thermal environment for winged reentry vehicles at flight conditions, a computational solution for the flow about the Shuttle Orbiter at wind tunnel conditions was made using a point-implicit, finite volume scheme known as the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA). The surface pressures resulting from the computational solution are compared with wind tunnel data. The results indicate that the dominant inviscid flow features are being accurately predicted on the leeside of the Shuttle Orbiter at a moderately high angle of attack.

  13. The Effect of Small Angles of Yaw and Pitch on the Characteristics of Airplane Propellers

    NASA Technical Reports Server (NTRS)

    Freeman, Hugh B

    1932-01-01

    This report presents the results of wind tunnel tests to determine the effect on the characteristics of a propeller of inclining the propeller axis at small angles to the relative wind. Tests were made of a full-scale propeller and fuselage combination at four angles of yaw (0 degree, +5 degrees, +10 degrees, +15 degrees), and of a model propeller, nacelle, and wing combination of five angles of pitch (-5 degrees, 0 degree, +5 degrees, +10 degrees and +15 degrees). The results of the full-scale tests of a propeller and fuselage, without a wing, show that the effect on the propeller performance is small. Similar results are shown by the model test data except that where the propeller is directly in front of the wing there is an appreciable decrease in effective thrust and propulsive efficiency with increase of angle of pitch.

  14. Definition, transformation-formulae and measurements of tipvane angles

    NASA Astrophysics Data System (ADS)

    Bruining, A.

    1987-10-01

    The theoretical background of different angle systems used to define tipvane attitude in 3-D space is outlined. Different Euler equations are used for the various, wind tunnel, towing tank, and full scale tipvane models. The influence of rotor blade flapping angle on tipvane angles is described. The tipvane attitude measuring method is outlined in relationship to the Euler angle system. Side effects on the angle of attack of the tipvane due to rotation, translation, and curving of the tipvane are described.

  15. Shuttle Program. Euler angles, quaternions, and transformation matrices working relationships

    NASA Technical Reports Server (NTRS)

    Henderson, D. M.

    1977-01-01

    A brief mathematical development of the relationship between the Euler angles and the transformation matrix, the quaternion and the transformation matrix, and the Euler angles and the quaternion is presented. The analysis and equations presented apply directly to current space shuttle problems. The twelve three-axis Euler transformation matrices are given as functions of the Euler angles, the equations for the quaternion as a funtion of the Euler angles, and the Euler angles as a function of the transformation matrix elements.

  16. A simple accurate algorithm for the critical angle refractometer

    NASA Astrophysics Data System (ADS)

    Ye, Junwei; Tao, Luo; Yang, Kecheng; Xia, Min; Li, Wei; Guo, Wenping; Liu, Hao

    2013-09-01

    We present a fast, simple, sub-pixel algorithm on the critical angle refractometer to measure the refractive index of the liquid sample by determining the centroid of the light intensity of the relative reflective curve. The centroid algorithm utilizes a divergent fiber-coupled royal blue LED source to irradiate on the dielectric surface between the prism and the media, which generates the light intensity distribution of the reflectance facula. Instead of the critical angle pixel as the differential algorithm and the threshold algorithm, the sub pixel centroid algorithm is based on calculating the centroid value of the light intensity of the relative reflective curve. In some moderate turbid solutions, the centroid algorithm is less sensitive to the scattering and absorption than the differential algorithm and the threshold algorithm. It is possible to utilize the centroid point of the relative reflective curve to determine the refractive index. Supported by the theoretical analysis and experimental results on saline solutions, we can conclude that the proposed algorithm is effective to get the super resolution and meaningful to the refractive index measurement of the liquid. The critical angle refractometer with this centroid method is potential to be a high-accuracy, high-resolution, and reliable automatic refractometer.

  17. Low-angle X-ray scattering from spices

    NASA Astrophysics Data System (ADS)

    Desouky, Omar S.; Ashour, Ahmed H.; Abdullah, Mohamed I.; Elshemey, Wael M.

    2002-07-01

    Low-angle scattering of X-rays is characterized by the presence of one or more peaks in the forward direction of scattering. These peaks are due to the interference of photons coherently scattered from the molecules of the medium. Thus these patterns are closely linked to the molecular structure of the investigated medium. In this work, low-angle X-ray scattering (LAXS) profiles of five spices; pimpinella anisum (anise), coriandrum sativum (coriander), cuminum cyminum (cumin), foenculum vulgare (fennel) and nigella sativa (nigella or black cumin) are presented after extensive measurements. It is found that all spices exhibit one characteristic peak at a scattering angle around 10°. This is equivalent to a value x=0.0565 Å -1, where x=sin( ??2)? ?. The full width at half maximum (FWHM) of this peak is found to be characteristic for each type of the investigated spices. The possibility to detect the irradiation of these spices from their LAXS profiles is also examined after 10, 20, 30 and 40 kGy doses of gamma radiation. Except for anise, coriander and cumin at 40 kGy, there are no detectable deviations from the control samples in the scattering profiles of irradiated samples. These results comply with the recommendations of the FDA (US Food and Drug Administration) which defines 30 kGy as the maximum dose for irradiation of spices. The present technique could be used to detect over-irradiation, which causes damage to the molecular structure of some spices.

  18. New approach to pitch angle scattering in the magnetosphere

    SciTech Connect

    Retterer, J.M.; Jasperse, J.R.; Chang, T.S.

    1983-01-01

    We develop a theory to describe the spatial variation of the particle pitch angle distribution function along a geomagnetic field line. Because spatial variation is most significant inside the loss cone, our theory is tailored to that part of velocity space. A boundary layer equation for the loss cone is derived and then solved. The description of the pitch angle distribution is completed by asymptotically matching the boundary-layer solution to the distribution outside the loss cone, which can be obtained by using the bounce-average diffusion equation. Calculated results for the particle distribution function in representative cases are presented. We apply our theory to ISIS 2 electron flux data for the continuous aurora to deduce the magnitude and the energy dependence of the pitch angle diffusion coefficient. We find that the diffusion coefficient is peaked at the invariant latitude at which the total energy flux into the atmosphere is largest, and that its energy dependence can be fitted with a power law E/sup -n/, with 1/2 < or approx. =n< or approx. =1.

  19. Orbit Propagation Strategies with Angle-Only Observations

    NASA Astrophysics Data System (ADS)

    Früh, Carolin; Schildknecht, Thomas

    Precise orbit determination and prediction plays an increasingly important role the more dense the population of resident space objects becomes. In this paper different strategies are dis-cussed how to propagate an orbit with angle-only observations. Different orbital regimes are investigated as well as the influence of the temporal spacing of observations. The focus is on objects which do not perform manoeuvres to clearly separate the effects of, probably unavail-able and/or inaccurate, manoeuvre data from modeling the natural forces. Orbit determination and propagation is performed with an enhanced version of the CelMech tool (Beutler, Meth-ods of Celestrical Mechanics, Springer 2001). The ephemerides of the propagated orbits are compared to observations of the same object, which were not used for orbit determination. These additional angle-only observations serve as a ground truth. The data is analyzed with respect to predicted and actually observed covariances. As a reference two line element data (TLEs) of the US Strategic Command (USSTRATCOM) catalogue are propagated with the SDP4 propagator and the resulting ephemerides are compared to the angle-only observations.

  20. Influence of substrate temperature on glancing angle deposited Ag nanorods

    SciTech Connect

    Khare, C.; Patzig, C.; Gerlach, J. W.; Rauschenbach, B.; Fuhrmann, B. [Leibniz Institute of Surface Modification, Permoserstrasse 15, 04318 Leipzig (Germany); Interdisciplinary Centre of Materials Science, Martin-Luther-University Halle, Heinrich-Damerow-Strasse 4, 06120 Halle (Germany)

    2010-07-15

    When Ag sculptured thin films were grown with glancing angle deposition by ion beam sputtering at either room temperature or elevated substrate temperatures T{sub S}, a large morphological difference was observed. The incident particle flux reached the silicon substrate at a glancing angle {beta}{>=}80 deg. as measured to the substrate normal. A slit aperture was used in order to reduce the particle beam divergence. At room temperature, columnar structures were formed, irrespective of the presence of the slit aperture. At elevated temperatures (573 and 623 K) and collimated particle flux in the presence of the slit aperture, however, enhanced surface diffusion causes the growth of crystalline nanorod- and nanowirelike structures. In the absence of the slit aperture, the flux beam divergence is higher, resulting in island- and mountainlike crystalline structures. The density of the nanorods and nanowires was observed to be higher on the planar Si substrates in comparison to honeycomblike prepatterned substrates with different pattern periods. On the patterned substrates, the nanorods are not necessarily found to be evolving on the seed points but can rather be also observed in-between the artificial seeds. The glancing angle deposited films at high temperatures were observed to be polycrystalline, where the (111) crystal orientation of the film is dominant, while the presence of the less intense (200) reflection was noticed from the x-ray diffraction measurements. In contrast, compact thin films deposited with {beta}{approx_equal}0 deg. at high temperatures were found to be epitaxial with (200) orientation.

  1. Laser Tracker Calibration - Testing the Angle Measurement System -

    SciTech Connect

    Gassner, Georg; Ruland, Robert; /SLAC

    2008-12-05

    Physics experiments at the SLAC National Accelerator Laboratory (SLAC) usually require high accuracy positioning, e. g. 100 {micro}m over a distance of 150 m or 25 {micro}m in a 10 x 10 x 3 meter volume. Laser tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. The accuracy of these measurements is related to the manufacturing tolerances of various individual components, the resolutions of measurement systems, the overall precision of the assembly, and how well imperfections can be modeled. As with theodolites and total stations, one can remove the effects of most assembly and calibration errors by measuring targets in both direct and reverse positions and computing the mean to obtain the result. However, this approach does not compensate for errors originating from the encoder system. In order to improve and gain a better understanding of laser tracker angle measurement tolerances we extended our laboratory's capabilities with the addition of a horizontal angle calibration test stand. This setup is based on the use of a high precision rotary table providing an angular accuracy of better than 0.2 arcsec. Presently, our setup permits only tests of the horizontal angle measurement system. A test stand for vertical angle calibration is under construction. Distance measurements (LECOCQ & FUSS, 2000) are compared to an interferometer bench for distances of up to 32 m. Together both tests provide a better understanding of the instrument and how it should be operated. The observations also provide a reasonable estimate of covariance information of the measurements according to their actual performance for network adjustments.

  2. Applicability of Washburn capillary rise for determining contact angles of powders/porous materials.

    PubMed

    Kirdponpattara, Suchata; Phisalaphong, Muenduen; Newby, Bi-min Zhang

    2013-05-01

    The Washburn capillary rise (WCR) technique has been widely utilized for determining contact angles of powders or porous materials; however, there are concerns regarding powder size and powder packing, especially for materials that exhibit large contact angle hysteresis. In this paper, some of these concerns were addressed. Due to the large water contact angle hysteresis on flat nylon 6/6 films, these films were ground into powders of different sizes and then used as model packing materials. The powders were packed in glass tubes to result in various packing structures that affected the penetration (i.e. advancing) rate of the test liquids. While all advancing contact angles obtained from WCR were found to be overestimated, more reasonable values were resulted when relatively large powders (e.g. 500-2000 ?m) were used to pack the tubes. With larger powders, the packing contained bigger voids and consequently lead to slower penetration rates of the liquids, hence a relatively smaller advancing contact angle. The smaller advancing contact angle obtained from the slower advancing rate was also observed by using the sessile drop method. To verify the applicability of using large powders (500-2000 ?m) for contact angle determination by using WCR, the advancing water contact angles of a bacterial cellulose/alginate composite sponge (BCA) with and without UV/ozone treatment were measured. The results showed that by using relatively large powders, WCR could be applied to obtain a reasonable advancing contact angle and assess the wettability change of complex porous materials. PMID:23484765

  3. Effect of anastomosis angle on hemodynamic of side-to-end radiocephalic arteriovenous fistula (RCAVF)

    NASA Astrophysics Data System (ADS)

    Hassan, Wan Anuar Wan; Osman, Kahar; Kadir, Mohammed Rafiq Abdul; Abdullah, Wan Ahmad Kamil Wan; Haron, Juhara; Ngali, Mohd Zamani

    2012-06-01

    Radiocephalic arteriovenous fistula (RCAVF) at wrist is the chosen access for hemodialysis. Most studies describe access complications without considering the effect of the anastomosis angle. In the present investigation, eighteen three-dimensional, simplified models of RCAVF were used to analyze the hemodynamic effect of anastomosis angle under fixed flow rate of 900 ml/min, corresponding to Reynolds number 950. EFD. Lab software was used in the flow simulation with steady flow conditions. The results show that high pressure drop was observed for RCAVF with smaller anastomosis angle. However, for cases with anastomosis angle larger than 45°, pressure drop became relatively constant. The results also show that large vortices appeared in cases with angle smaller than 30°. For cases with angle larger than 60°, low flow zone appeared at the inner wall that may lead to promotion of intimal thickening and formation of stenosis. Overall, for average flowrate, it is recommended that anastomosis angle should be maintained between 45° and 60° to minimize adverse effects.

  4. Relationship between mandibular condyle and angle fractures and the presence of mandibular third molars

    PubMed Central

    Mah, Deuk-Hyun; Moon, Seong-Yong; Oh, Ji-Su; You, Jae-Seek

    2015-01-01

    Objectives We retrospectively evaluated the impact of mandibular third molars on the occurrence of angle and condyle fractures. Materials and Methods This was a retrospective investigation using patient records and radiographs. The sample set consisted of 440 patients with mandibular fractures. Eruption space, depth and angulation of the third molar were measured. Results Of the 144 angle fracture patients, 130 patients had third molars and 14 patients did not. The ratio of angle fractures when a third molar was present (1.26 : 1) was greater than when no third molar was present (0.19 : 1; odds ratio, 6.58; P<0.001). Of the 141 condyle fractures patients, the third molar was present in 84 patients and absent in 57 patients. The ratio of condyle fractures when a third molar was present (0.56 : 1) was lower than when no third molar was present (1.90 : 1; odds ratio, 0.30; P<0.001). Conclusion The increased ratio of angle fractures with third molars and the ratio of condyle fractures without a third molar were statistically significant. The occurrence of angle and condyle fractures was more affected by the continuity of the cortical bone at the angle than by the depth of a third molar. These results demonstrate that a third molar can be a determining factor in angle and condyle fractures. PMID:25741462

  5. Effect of Anteromedial Portal Entrance Drilling Angle during Anterior Cruciate Ligament Reconstruction: A Three-Dimensional Computer Simulation

    PubMed Central

    Moon, Dong Kyu; Yoon, Chul Ho; Park, Jin Seung; Kang, Bun Jung; Cho, Seong Hee; Jo, Ho Seung

    2014-01-01

    Purpose The object of this study was to evaluate entrance angle effects on femoral tunnel length and cartilage damage during anteromedial portal drilling using three-dimensional computer simulation. Materials and Methods Data was obtained from an anatomic study performed using 16 cadaveric knees. The anterior cruciate ligament femoral insertion was dissected and the knees were scanned by computer tomography. Tunnels with different of three-dimensional entrance angles were identified using a computer simulation. The effects of different entrance angles on the femoral tunnel length and medial femoral cartilage damage were evaluated. Specifically, tunnel length and distance from the medial femoral condyle to a virtual cylinder of the femoral tunnel were measured. Results In tunnels drilled at a coronal angle of 45°, an axial angle of 45°, and a sagittal angle of 45°, the mean femoral tunnel length was 39.5±3.7 mm and the distance between the virtual cylinder of the femoral tunnel and the medial femoral condyle was 9.4±2.6 mm. The tunnel length at a coronal angle of 30°, an axial angle of 60°, and a sagittal angle of 45°, was 34.0±2.9 mm and the distance between the virtual cylinder of the tunnel and the medial femoral condyle was 0.7±1.3 mm, which was significantly shorter than the standard angle (p<0.001). Conclusion Extremely low and high entrance angles in both of axial plane and coronal plane produced inappropriate tunnel angles, lengths and higher incidence of cartilage damage. We recommend that angles in proximity to standard angles be chosen during femoral tunnel drilling through the anteromedial portal. PMID:25323895

  6. Lunar Reconnaissance Orbiter Camera Narrow Angle Cameras: Laboratory and Initial Flight Calibration

    NASA Astrophysics Data System (ADS)

    Humm, D. C.; Tschimmel, M.; Denevi, B. W.; Lawrence, S.; Mahanti, P.; Tran, T. N.; Thomas, P. C.; Eliason, E.; Robinson, M. S.

    2009-12-01

    The Lunar Reconnaissance Orbiter Camera (LROC) has two identical Narrow Angle Cameras (NACs). Each NAC is a monochrome pushbroom scanner, providing images with a pixel scale of 50 cm from a 50-km orbit. A single NAC image has a swath width of 2.5 km and a length of up to 26 km. The NACs are mounted to acquire side-by-side imaging for a combined swath width of 5 km. The NAC is designed to fully characterize future human and robotic landing sites in terms of scientific and resource merit, trafficability, and hazards. The North and South poles will be mapped at 1-meter-scale poleward of 85.5 degrees latitude. Stereo coverage is achieved by pointing the NACs off-nadir, which requires planning in advance. Read noise is 91 and 93 e- and the full well capacity is 334,000 and 352,000 e- for NAC-L and NAC-R respectively. Signal-to-noise ranges from 42 for low-reflectance material with 70 degree illumination to 230 for high-reflectance material with 0 degree illumination. Longer exposure times and 2x binning are available to further increase signal-to-noise with loss of spatial resolution. Lossy data compression from 12 bits to 8 bits uses a companding table selected from a set optimized for different signal levels. A model of focal plane temperatures based on flight data is used to command dark levels for individual images, optimizing the performance of the companding tables and providing good matching of the NAC-L and NAC-R images even before calibration. The preliminary NAC calibration pipeline includes a correction for nonlinearity at low signal levels with an offset applied for DN>600 and a logistic function for DN<600. Flight images taken on the limb of the Moon provide a measure of stray light performance. Averages over many lines of images provide a measure of flat field performance in flight. These are comparable with laboratory data taken with a diffusely reflecting uniform panel.

  7. Two Years of Digital Terrain Model Production Using the Lunar Reconnaissance Orbiter Narrow Angle Camera

    NASA Astrophysics Data System (ADS)

    Burns, K.; Robinson, M. S.; Speyerer, E.; LROC Science Team

    2011-12-01

    One of the primary objectives of the Lunar Reconnaissance Orbiter Camera (LROC) is to gather stereo observations with the Narrow Angle Camera (NAC). These stereo observations are used to generate digital terrain models (DTMs). The NAC has a pixel scale of 0.5 to 2.0 meters but was not designed for stereo observations and thus requires the spacecraft to roll off-nadir to acquire these images. Slews interfere with the data collection of the other instruments, so opportunities are currently limited to four per day. Arizona State University has produced DTMs from 95 stereo pairs for 11 Constellation Project (CxP) sites (Aristarchus, Copernicus crater, Gruithuisen domes, Hortensius domes, Ina D-caldera, Lichtenberg crater, Mare Ingenii, Marius hills, Reiner Gamma, South Pole-Aitkin Rim, Sulpicius Gallus) as well as 30 other regions of scientific interest (including: Bhabha crater, highest and lowest elevation points, Highland Ponds, Kugler Anuchin, Linne Crater, Planck Crater, Slipher crater, Sears Crater, Mandel'shtam Crater, Virtanen Graben, Compton/Belkovich, Rumker Domes, King Crater, Luna 16/20/23/24 landing sites, Ranger 6 landing site, Wiener F Crater, Apollo 11/14/15/17, fresh craters, impact melt flows, Larmor Q crater, Mare Tranquillitatis pit, Hansteen Alpha, Moore F Crater, and Lassell Massif). To generate DTMs, the USGS ISIS software and SOCET SET° from BAE Systems are used. To increase the absolute accuracy of the DTMs, data obtained from the Lunar Orbiter Laser Altimeter (LOLA) is used to coregister the NAC images and define the geodetic reference frame. NAC DTMs have been used in examination of several sites, e.g. Compton-Belkovich, Marius Hills and Ina D-caldera [1-3]. LROC will continue to acquire high-resolution stereo images throughout the science phase of the mission and any extended mission opportunities, thus providing a vital dataset for scientific research as well as future human and robotic exploration. [1] B.L. Jolliff (2011) Nature Geoscience, in press. [2] Lawrence et al. (2011) LPSC XLII, Abst 2228. [3] Garry et al. (2011) LPSC XLII, Abst 2605.

  8. View angle effects in the radiometric measurement of plant canopy temperatures

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Idso, S. B.; Pinter, P. J., Jr.; Reginato, R. J.; Jackson, R. D.

    1980-01-01

    The thermal infrared sensor response from a wheat canopy was extremely non-Lambertian because of spatial variations in energy flow processes; the effective radiant temperature of the sensor varied as much as 13 C with changing view angle. This variation of sensor response was accurately quantified (root-mean-square of deviations between theoretical and measured responses reduced to 1.1 C) as a function of vegetation canopy geometry, vertical temperature distribution of canopy components, and sensor view angle. The results have important implications for optimizing sensor view angles for remote sensing missions.

  9. The Use of Accelerometers and Gyroscopes to Estimate Hip and Knee Angles on Gait Analysis

    PubMed Central

    Alonge, Francesco; Cucco, Elisa; D'Ippolito, Filippo; Pulizzotto, Alessio

    2014-01-01

    In this paper the performance of a sensor system, which has been developed to estimate hip and knee angles and the beginning of the gait phase, have been investigated. The sensor system consists of accelerometers and gyroscopes. A new algorithm was developed in order to avoid the error accumulation due to the gyroscopes drift and vibrations due to the ground contact at the beginning of the stance phase. The proposed algorithm have been tested and compared to some existing algorithms on over-ground walking trials with a commercial device for assisted gait. The results have shown the good accuracy of the angles estimation, also in high angle rate movement. PMID:24828578

  10. Different studies of the global pitch angle of the Milky Way's spiral arms

    E-print Network

    Vallee, Jacques P

    2015-01-01

    There are many published values for the pitch angle of individual spiral arms, and their wide distribution (from -3 to -28 degrees) begs for various attempts for a single value. Each of the four statistical methods used here yields a mean pitch angle in a small range, between -12 and -14 degrees (table 7, figure 2). The final result of our meta-analysis yields a mean global pitch angle in the Milky Way's spiral arms of -13.1 degrees, plus or minus 0.6 degree.

  11. Measurement of the angle alpha at BABAR

    SciTech Connect

    Perez, A.; /Orsay, LAL

    2009-06-25

    The authors present recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory, operating at the {Upsilon}(4S) resonance. They present constraints on {alpha} from B {yields} {pi}{pi}, B {yields} {rho}{rho} and B {yields} {rho}{pi} decays.

  12. Inclination angle of vector magnetic fields.

    NASA Astrophysics Data System (ADS)

    Yanping, Lü; Wang, Jingxiu

    1994-11-01

    The authors further elaborate on an empirical method to improve the consistency of the line-of-sight and transverse field calibration. The method can also be used to check the transverse field calibration. Furthermore, based on the correction, the authors calculate the inclination angle of the vector magnetic field related to the solar surface, which can give some information on how the vector magnetic field is distributed in space.

  13. Tool Indicates Contact Angles In Bearing Raceways

    NASA Technical Reports Server (NTRS)

    Akian, Richard A.; Butner, Myles F.

    1995-01-01

    Tool devised for use in measuring contact angles between balls and races in previously operated ball bearings. Used on both inner and outer raceways of bearings having cross-sectional widths between approximately 0.5 and 2.0 in. Consists of integral protractor mounted in vertical plane on bracket equipped with leveling screws and circular level indicator. Protractor includes rotatable indicator needle and set of disks of various sizes to fit various raceway curvatures.

  14. Towards the Extraction of the CKM Angle $?$

    E-print Network

    Robert Fleischer

    1998-09-08

    The determination of the angle $\\gamma$ of the unitarity triangle of the CKM matrix is regarded as a challenge for future $B$-physics experiments. In this context, the decays $B^\\pm\\to \\pi^\\pm K$ and $B_d\\to\\pi^\\mp K^\\pm$, which were observed by the CLEO collaboration last year, received a lot of interest in the literature. After a general parametrization of their decay amplitudes, strategies to constrain and determine the CKM angle $\\gamma$ with the help of the corresponding observables are reviewed. The theoretical accuracy of these methods is limited by certain rescattering and electroweak penguin effects. It is emphasized that the rescattering processes can be included in the bounds on $\\gamma$ by using additional experimental information on $B^\\pm\\to K^\\pm K$ decays, and steps towards the control of electroweak penguins are pointed out. Moreover, strategies to probe the CKM angle $\\gamma$ with the help of $B_s\\to K\\bar{K}$ decays are briefly discussed.

  15. Small Angle X-Ray Scattering Detector

    DOEpatents

    Hessler, Jan P. (Downers Grove, IL)

    2004-06-15

    A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., q.sub.max /q.sub.min.congruent.100.

  16. Angle sensitive single photon avalanche diode

    NASA Astrophysics Data System (ADS)

    Lee, Changhyuk; Johnson, Ben; Molnar, Alyosha

    2015-06-01

    An ideal light sensor would provide exact information on intensity, timing, location, and angle of incoming photons. Single photon avalanche diodes (SPADs) provide such desired high (single photon) sensitivity with precise time information and can be implemented at a pixel-scale to form an array to extract spatial information. Furthermore, recent work has demonstrated photodiode-based structures (combined with micro-lenses or diffraction gratings) that are capable of encoding both spatial and angular information of incident light. In this letter, we describe the implementation of such a grating structure on SPADs to realize a pixel-scale angle-sensitive single photon avalanche diode (A-SPAD) built in a standard CMOS process. While the underlying SPAD structure provides high sensitivity, the time information of the two layers of diffraction gratings above offers angle-sensitivity. Such a unique combination of SPAD and diffraction gratings expands the sensing dimensions to pave a path towards lens-less 3-D imaging and light-field time-of-flight imaging.

  17. The Weak Angle and Quark Masses

    NASA Astrophysics Data System (ADS)

    Dannon, Vic

    2000-04-01

    The weak angle discerns a basic quark mass through mu div md div ms div mc div mb div mt ? 1 div ( frac1 sin ? W ) div ( frac1 sin ^5 ? W ) div ( frac1 sin ^8 ? W ) div ( frac1 sin ^10 ? W ) div ( frac1 sin ^15 ? W ) Within families mu div md ? sin ? _W, ms div mc ? sin^3 ? _W, and mb div mt ? sin^5 ? _W, are complementary to the relations sin ? 1 ? sin ^2 ? _W, sin ? 2 ? sin ^4 ? _W, and sin ? 3 ? sin ^6 ? W validated* by the CKM matrix data where ? W ? arcsin ? 0.23, and the CKM matrix is the product ( 1 & 0 & 0 0 & c2 & s2 0 & - s2 & c2 )( c1 & s1 & 0 - s1 & c1 & 0 0 & 0 & 1 )( 1 & 0 & 0 0 & 1 & 0 0 & 0 & e^i? )( 1 & 0 & 0 0 & c3 & s3 0 & - s3 & c3 ) based on the mixing angles, ? 1 ,? 2 ,? 3 , and ?. ci = \\cos ?_i, and s_i= sin ?_i. Thus, ( fracmu md ) div sin ? 1 div ( fracms mc ) div sin ? 2 div ( fracmb mt ) div sin ? 3 ? sin ? W div sin ^2 ? W div sin ^3 ? W div sin ^4 ? W div sin ^5 ? W div sin ^6 ? W . ["Cabbibo Angle Approximation CKM matrix", Bull.Vol.44, No.9

  18. Wet surface heat transfer and pressure drop of aluminum parallel flow heat exchangers at different inclination angles

    Microsoft Academic Search

    Nae-Hyun Kim; Do-Young Kim; Jun-Hyun Hwang

    2008-01-01

    The effect of inclination angle on the heat transfer and pressure drop characteristics of brazed aluminum heat exchangers\\u000a was experimentally investigated under wet conditions. Three samples having different fin pitches (1.25, 1.5 and 2.0 mm) were\\u000a tested. Results show that heat transfer coefficients are not affected by the inclination angle. However, friction factors\\u000a increase as the inclination angle increases with

  19. Interference effects of aircraft components on the local blade angle of attack of a wing-mounted propeller

    NASA Technical Reports Server (NTRS)

    Mendoza, J. P.

    1979-01-01

    The aerodynamic interference effects on a propeller operating in the presence of different wing-body-nacelle combinations was studied. The unsteady blade angle of attack variation with azimuth angle by varying the pitch and yaw of the nacelle was minimized. Results indicate for the particular configuration of interest the minimum blade angle of attack variation occurred with the nacelle pitched downward 4.5 deg and yawed inward 3.0 deg.

  20. Study of critical ricochet angle for conical nose shape projectiles

    NASA Astrophysics Data System (ADS)

    Murali, Vijayalakshmi; Law, Manish G.; Naik, Smita D.

    2012-09-01

    The purpose of this research is to formulate a generic analytical model to assess the phenomena of water ricochet for a conical nose shaped projectile. A theoretical model is analyzed to study the critical angle of conical nose shaped projectile entering in water and is extended for different mediums as normal sand and mercury. Numerical Simulation has been carried out to find the effect of tip angle of the conical nose shaped projectile on the critical angle. Critical angle is defined as that angle of impact of the projectile above which ricochet will occur. This angle is obtained by balancing the momentums acting on the projectile at the time of impact on the basis of Newtonian theory. Major factors affecting critical angle are impact velocity, impact angle, density of the projectile and the target. An attempt has been made to study the effect of longitudinal spin of the projectile on the critical angle.

  1. An improved method for calibrating the gantry angles of linear accelerators.

    PubMed

    Higgins, Kyle; Treas, Jared; Jones, Andrew; Fallahian, Naz Afarin; Simpson, David

    2013-11-01

    Linear particle accelerators (linacs) are widely used in radiotherapy procedures; therefore, accurate calibrations of gantry angles must be performed to prevent the exposure of healthy tissue to excessive radiation. One of the common methods for calibrating these angles is the spirit level method. In this study, a new technique for calibrating the gantry angle of a linear accelerator was examined. A cubic phantom was constructed of Styrofoam with small lead balls, embedded at specific locations in this foam block. Several x-ray images were taken of this phantom at various gantry angles using an electronic portal imaging device on the linac. The deviation of the gantry angles were determined by analyzing the images using a customized computer program written in ImageJ (National Institutes of Health). Gantry angles of 0, 90, 180, and 270 degrees were chosen and the results of both calibration methods were compared for each of these angles. The results revealed that the image method was more precise than the spirit level method. For the image method, the average of the measured values for the selected angles of 0, 90, 180, and 270 degrees were found to be -0.086 ± 0.011, 90.018 ± 0.011, 180.178 ± 0.015, and 269.972 ± 0.006 degrees, respectively. The corresponding average values using the spirit level method were 0.2 ± 0.03, 90.2 ± 0.04, 180.1 ± 0.01, and 269.9 ± 0.05 degrees, respectively. Based on these findings, the new method was shown to be a reliable technique for calibrating the gantry angle. PMID:24077078

  2. A two camera video imaging system with application to parafoil angle of attack measurements

    NASA Technical Reports Server (NTRS)

    Meyn, Larry A.; Bennett, Mark S.

    1991-01-01

    This paper describes the development of a two-camera, video imaging system for the determination of three-dimensional spatial coordinates from stereo images. This system successfully measured angle of attack at several span-wise locations for large-scale parafoils tested in the NASA Ames 80- by 120-Foot Wind Tunnel. Measurement uncertainty for angle of attack was less than 0.6 deg. The stereo ranging system was the primary source for angle of attack measurements since inclinometers sewn into the fabric ribs of the parafoils had unknown angle offsets acquired during installation. This paper includes discussions of the basic theory and operation of the stereo ranging system, system measurement uncertainty, experimental set-up, calibration results, and test results. Planned improvements and enhancements to the system are also discussed.

  3. Beam angle manipulation to reduce cardiac dose during breast radiotherapy

    PubMed Central

    Vivekanandan, S; Mhlanga, J; Launders, D; Przeslak, A; Morgan, D A L

    2012-01-01

    Objective Standard tangential radiotherapy techniques after breast conservative surgery (BCS) often results in the irradiation of the tip of the left ventricle and the left anterior descending coronary artery (LAD), potentially increasing cardiovascular morbidity. The importance of minimising radiation dose to these structures has attracted increased interest in recent years. We tested a hypothesis that in some cases, by manipulating beam angles and accepting lower-than-prescribed doses of radiation in small parts of the breast distant from the surgical excision site, significant cardiac sparing can be achieved compared with more standard plans. Methods A sample of 12 consecutive patients undergoing radiotherapy after left-sided BCS was studied. All patients were planned with a 6 MV tangential beam, beam angles were manipulated carefully and if necessary lower doses were given to small parts of the breast distant from the surgical excision site to minimise cardiac irradiation (“institutional” plan). Separate “hypothetical standard” plans were generated for seven patients using set field margins that met published guidelines. Results In seven patients, the institutional plans resulted in lower doses to the LAD and myocardium than the hypothetical standard plans. In the other five patients, LAD and myocardial doses were deemed minimal using the hypothetical standard plan, which in these patients corresponded to the institutional plan (the patients were actually treated using the institutional plans). Conclusion Much attention has been devoted to ways of minimising cardiac radiation dose. This small sample demonstrates that careful manipulation of beam angles can often be a simple, but effective technique to achieve this. PMID:21750129

  4. Mechanical basis for slip along low-angle normal faults

    NASA Astrophysics Data System (ADS)

    Lecomte, E.; Le Pourhiet, L.; Lacombe, O.

    2012-04-01

    The existence of active low-angle normal faults is much debated because (1) the classical theory of fault mechanics implies that normal faults are locked when the dip is less than 30° and (2) shallow-dipping extensional fault planes do not produce large earthquakes (M > 5.5). However, a number of field observations suggest that brittle deformation occurs on low-angle normal faults at very shallow dip. To reconcile observations and theory, we use an alternative model of fault reactivation including a thick elasto-plastic frictional fault gouge, and test it at large strain by the mean of 2D mechanical modeling. When the dilation angle of a thick fault zone is smaller than its friction angle, elastic strain occurs within the fault zone to ensure the compatibility of displacement. This strain results in a rotation of principal stresses within the fault and therefore modifies the effective friction of the fault. In this paper, we demonstrate that a component of compaction of the fault zone leads to a significant drop of the effective friction of LANFs which allows faults with internal friction of 0.3 to slip at dip as low as 20°. In this regime, the thick fault model predicts that deviatoric stress rises with accumulated plastic strain on LANFs, favoring a stable slip regime. These predictions are well supported by seismological observations and geodesy in the Gulf of Corinth. However, within the rotated state of stress of the fault zone, it is also possible to newly form secondary faults. These smaller faults form in a slip-weakening regime and are to that respect dynamically unstable. Their orientations depend on the dilation angle of the fault zone but in general, they are confined to the width of the fault zone and therefore their size is limited. Therefore, seismic activity on these secondary shears is necessarily of limited magnitude as it is often observed on active LANFs and other weak faults. Finally, the state of stress within the LANFs being close to steady state, the orientation of the instable secondary shear structures is constant in time, which favors the occurrence of multiplets along the shallow-dipping normal fault zone.

  5. Effect and evaluation of prying action for top- and seat-angle connections

    NASA Astrophysics Data System (ADS)

    Ahmed, Ali; Hasan, Rafiq

    2015-06-01

    Nonlinear finite element (FE) static analyses of top- and seat-angle connections were performed using ABAQUS standard to investigate the influence of connection parameters and its properties on prying action developed due to the interaction between column flange and top angle's vertical leg. Contact phenomenon between two interfaces with finite sliding and bolt pretension in the initial step of analysis was considered in the FE model. FE analysis results were compared with the experimental ones to examine the applicability of the FE model. Then, the location of plastic hinges in connection assemblages was investigated at the ultimate state of the connection and a parametric study was performed varying connection parameters, material properties of connection assemblages, and magnitude of bolt pretension to visualize their effects on prying force and on the position of prying force on top angle's vertical leg. Current study shows that plastic hinges not only develop at top angle's heel and bolt hole region but also in the bolt shank that differs from some assumptions of power model (Kishi and Chen 1990): (1) top angle thickness and gage distance from angle heel to bolt hole center line have an distinct effect on prying action; and (2) distributed prying force developed near the region of the top edge of tension angle's leg adjacent to column flange can contribute to the failure of the connection. Finally, a mathematical formulation to identify the location of prying force action point is proposed.

  6. Joint torque and angle estimation by using ultrasonic muscle activity sensor

    NASA Astrophysics Data System (ADS)

    Tsutsui, Yoichiro; Tanaka, Takayuki; Kaneko, Shun'ichi; Feng, Maria Q.

    2005-12-01

    We have proposed a brand-new noninvasive ultrasonic sensor for measuring muscle activities named as Ultrasonic Muscle Activity Sensor (UMS). In the previous paper, the authors achieved to accurately estimate joint torque by using UMS and electromyogram (EMG) which is one of the most popular sensors. This paper aims to realize to measure not only joint torque also joint angle by using UMS and EMG. In order to estimate torque and angle of a knee joint, muscle activities of quadriceps femoris and biceps femoris were measured by both UMS and EMG. These targeted muscles are related to contraction and extension of knee joint. Simultaneously, actual torque on the knee joint caused by these muscles was measured by using torque sensor. The knee joint angle was fixed by torque sensor in the experiment, therefore the measurement was in isometric state. In the result, we found that the estimated torque and angle have high correlation coefficient to actual torque and angle. This means that the sensor can be used for angle estimation as well torque estimation. Therefore, it is shown that the combined use of UMS and EMG is effective to torque and angle estimation.

  7. Effect and evaluation of prying action for top- and seat-angle connections

    NASA Astrophysics Data System (ADS)

    Ahmed, Ali; Hasan, Rafiq

    2015-04-01

    Nonlinear finite element (FE) static analyses of top- and seat-angle connections were performed using ABAQUS standard to investigate the influence of connection parameters and its properties on prying action developed due to the interaction between column flange and top angle's vertical leg. Contact phenomenon between two interfaces with finite sliding and bolt pretension in the initial step of analysis was considered in the FE model. FE analysis results were compared with the experimental ones to examine the applicability of the FE model. Then, the location of plastic hinges in connection assemblages was investigated at the ultimate state of the connection and a parametric study was performed varying connection parameters, material properties of connection assemblages, and magnitude of bolt pretension to visualize their effects on prying force and on the position of prying force on top angle's vertical leg. Current study shows that plastic hinges not only develop at top angle's heel and bolt hole region but also in the bolt shank that differs from some assumptions of power model (Kishi and Chen 1990): (1) top angle thickness and gage distance from angle heel to bolt hole center line have an distinct effect on prying action; and (2) distributed prying force developed near the region of the top edge of tension angle's leg adjacent to column flange can contribute to the failure of the connection. Finally, a mathematical formulation to identify the location of prying force action point is proposed.

  8. PITCH ANGLE RESTRICTIONS IN LATE-TYPE SPIRAL GALAXIES BASED ON CHAOTIC AND ORDERED ORBITAL BEHAVIOR

    SciTech Connect

    Perez-Villegas, A.; Pichardo, B.; Moreno, E.; Peimbert, A. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A.P. 70-264, 04510 Mexico D.F. (Mexico); Velazquez, H. M., E-mail: barbara@astroscu.unam.mx [Observatorio Astronomico Nacional, Universidad Nacional Autonoma de Mexico, Apdo. Postal 877, 22800 Ensenada (Mexico)

    2012-01-20

    We built models for low bulge mass spiral galaxies (late type as defined by the Hubble classification) using a three-dimensional self-gravitating model for spiral arms, and analyzed the orbital dynamics as a function of pitch angle, ranging from 10 Degree-Sign to 60 Degree-Sign . Indirectly testing orbital self-consistency, we search for the main periodic orbits and studied the density response. For pitch angles up to approximately {approx}20 Degree-Sign , the response closely supports the potential readily permitting the presence of long-lasting spiral structures. The density response tends to 'avoid' larger pitch angles in the potential by keeping smaller pitch angles in the corresponding response. Spiral arms with pitch angles larger than {approx}20 Degree-Sign would not be long-lasting structures but would rather be transient. On the other hand, from an extensive orbital study in phase space, we also find that for late-type galaxies with pitch angles larger than {approx}50 Degree-Sign , chaos becomes pervasive, destroying the ordered phase space surrounding the main stable periodic orbits and even destroying them. This result is in good agreement with observations of late-type galaxies, where the maximum observed pitch angle is {approx}50 Degree-Sign .

  9. Strong Pitch-Angle Diffusion of Ring Current Ions in Geomagnetic Storm-Associated Conditions

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.; Spann, J. F.

    2005-01-01

    Do electromagnetic ion cyclotron (EMIC) waves cause strong pitch-angle diffusion of RC ions? This question is the primary motivation of this paper and has been affirmatively answered from the theoretical point of view. The materials that are presented in the Results section show clear evidence that strong pitch-angle diffusion takes place in the inner magnetosphere indicating an important role for the wave-particle interaction mechanism in the formation of RC ions and EMIC waves.

  10. Retroreflective effect on a right angle left-handed media prism.

    PubMed

    Monzon, Cesar; Forester, Donald W; Burkhart, Richard

    2006-03-01

    A different retroreflective effect which parallels that encountered with dihedral corner reflectors is found in the scattering response of a penetrable left-handed media epsilon= mu= -1 right angle prism. More significantly, no diffraction from the vertex is found to exist and hence no field singularity for the right angle wedge. Although the results are illustrated with microwaves, the concept finds applications in optics, acoustics, elasticity, and other media characterized by negative index wave propagation. PMID:16605690

  11. Factors associated with long-term progression or stability in primary open-angle glaucoma

    Microsoft Academic Search

    William C Stewart; Allan E Kolker; Elizabeth D Sharpe; Douglas G Day; Keri T Holmes; Jessica N Leech; Mark Johnson; Jennifer B Cantrell

    2000-01-01

    PURPOSE: To evaluate long-term risk factors for progression or stability in patients with primary open-angle glaucoma.METHOD: We retrospectively included consecutively reviewed patients who had primary open-angle glaucoma for at least 5 years in this multicenter trial. Historical and clinical factors in these patients were evaluated for their association with stability or progression of the glaucoma.RESULTS: We included 218 patients in

  12. A study of altitude and flight path angle dynamics for a singularly perturbed fuel optimization problem

    NASA Technical Reports Server (NTRS)

    Price, D. B.; Gracey, C.

    1983-01-01

    This short paper will demonstrate that the separation of altitude and flight path angle dynamics using singular perturbation techniques for a transport fuel optimization problem results in an unacceptable oscillation in altitude. A technique for damping this oscillation by adding a penalty term to the cost function for the optimization problem will be discussed. This technique will be compared with a different approach that linearizes the altitude and flight path angle boundary layers.

  13. The determination of shadowing critical angles in impact collision ion scattering spectroscopy

    Microsoft Academic Search

    Th. Fauster; D. Hartwig; H. Dürr

    1988-01-01

    Critical angles for shadowing in low-energy ion scattering spectroscopy are calculated in the momentum approximation for the Thomas-Fermi-Molière potential and the Ziegler-Biersack-Littmark potential. In the relevant parameter range the results can be fitted by a formula containing five constants depending on the potential only. For a fixed projectile-target combination at a given energy the distance dependence of the critical angle

  14. Small angle neutron scattering investigation of microporosity in marbles

    NASA Astrophysics Data System (ADS)

    Coppola, R.; Lapp, A.; Magnani, M.; Valli, M.

    Small angle neutron scattering (SANS) measurements have been carried out on different marble and limestone samples, of relevance to cultural heritage safeguard, to investigate the micropore size distribution. Different varieties of marble have been studied using a CaCO3 single crystal as a pore-free reference. A series of red scaglia limestone samples has also been studied, obtaining in this case identical SANS cross sections for specimens issued from a modern quarry and for samples issued from an historical building. The micropore volume distribution functions, obtained from the SANS data, are compared with porosimetry results.

  15. Calculations of transonic boattail flow at small angle of attack

    NASA Technical Reports Server (NTRS)

    Nakayama, A.; Chow, W. L.

    1979-01-01

    A transonic flow past a boattailed afterbody under a small angle of attack was examined. It is known that the viscous effect offers significant modifications of the pressure distribution on the afterbody. Thus, the formulation for the inviscid flow was based on the consideration of a flow past a nonaxisymmetric body. The full three dimensional potential equation was solved through numerical relaxation, and quasi-axisymmetric boundary layer calculations were performed to estimate the displacement effect. It was observed again that the viscous effects were not negligible. The trend of the final results agreed well with the experimental data.

  16. Measurement of the CKM Angle Alpha at BaBar

    SciTech Connect

    Yeche, C.; /Saclay

    2006-04-14

    We present BABAR experiment studies to measure the CKM angle {alpha} of the Unitarity Triangle. The measurements are based on the B meson decays into the two-body state ({pi}{pi}), the quasi two-body state ({rho}{rho}), and the three-body state ({pi}{sup +}{pi}{sup -}{pi}{sup 0}). The results are obtained from data samples of about 230 million {Upsilon}(4S) {yields} B{bar B} decays collected between 1999 and 2004 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.

  17. Geleophysic dysplasia associated with bilateral angle closure glaucoma

    PubMed Central

    Saricaoglu, Murat Sinan; Güven, Dilek; Karakurt, Ahmet; Hasiripi, Hikmet

    2013-01-01

    In this case report, we present occurrence of bilateral angle closure glaucoma in a 9-year-old girl with geleophysic dysplasia. Bilateral YAG laser iridotomy was applied, but intraocular pressure (IOP) remained at high levels, necessitating bilateral trabeculectomy with mitomycin C. On her follow-up examinations for 3 years, IOP remained in the mid-20s with no need for further intervention or antiglaucoma medication. There are few reports describing the ocular findings of geleophysic dysplasia in literature. To our knowledge, this is the first case report describing an application of glaucoma surgery and its results at geleophysic dysplasia. PMID:23514648

  18. Asymmetric domain walls of small angle in soft ferromagnetic films

    E-print Network

    Lukas Döring; Radu Ignat

    2014-12-07

    We focus on a special type of domain walls appearing in the Landau-Lifshitz theory for soft ferromagnetic films. These domain walls are divergence-free $S^2$-valued transition layers that connect two directions in $S^2$ (differing by an angle $2\\theta$) and minimize the Dirichlet energy. Our main result is the rigorous derivation of the asymptotic structure and energy of such "asymmetric" domain walls in the limit $\\theta \\to 0$. As an application, we deduce that a supercritical bifurcation causes the transition from symmetric to asymmetric walls in the full micromagnetic model.

  19. SCDU (Spectral Calibration Development Unit) Testbed Narrow Angle Astrometric Performance

    NASA Technical Reports Server (NTRS)

    Wang, Xu; Goullioud, Renaud; Nemati, Bijan; Shao, Michael; Wehmeier, Udo J.; Weilert, Mark A.; Werne, Thomas A.; Wu, Janet P.; Zhai, Chengxing

    2010-01-01

    The most stringent astrometric performance requirements on NASA's SIM(Space Interferometer Mission)-Lite mission will come from the so-called Narrow-Angle (NA) observing scenario, aimed at finding Earth-like exoplanets, where the interferometer chops between the target star and several nearby reference stars multiple times over the course of a single visit. Previously, about 20 pm NA error with various shifts was reported. Since then, investigation has been under way to understand the mechanisms that give rise to these shifts. In this paper we report our findings, the adopted mitigation strategies, and the resulting testbed performance.

  20. The small angle tile calorimeter in the DELPHI experiment

    NASA Astrophysics Data System (ADS)

    Alvsvaag, S. J.; Bari, M.; Barreira, G.; Benvenuti, A. C.; Bigi, M.; Bonesini, M.; Bozzo, M.; Camporesi, T.; Carling, H.; Cassio, V.; Castellani, L.; Cereseto, R.; Chignoli, F.; Della Ricca, G.; Dharmasiri, D. R.; Santo, M. C. Espirito; Falk, E.; Fenyuk, A.; Ferrari, P.; Gamba, D.; Giordano, V.; Gouz, Yu.; Guerzoni, M.; Gumenyuk, S.; Hedberg, V.; Jarlskog, G.; Karyukhin, A.; Klovning, A.; Konoplyannikov, A.; Kronkvist, I.; Lanceri, L.; Leoni, R.; Maeland, O. A.; Maio, A.; Mazza, R.; Migliore, E.; Navarria, F. L.; Negri, P.; Nossum, B.; Obraztsov, V.; Onofre, A.; Paganoni, M.; Pegoraro, M.; Peralta, L.; Petrovykh, L.; Pimenta, M.; Poropat, P.; Prest, M.; Read, A. L.; Romero, A.; Shalanda, N.; Simonetti, L.; Skaali, T. B.; Stugu, B.; Terranova, F.; Tome, B.; Torassa, E.; Trapani, P. P.; Verardi, M. G.; Vallazza, E.; Vlasov, E.; Zaitsev, A.

    1999-04-01

    The Small angle TIle Calorimeter (STIC) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called "shashlik" technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e-? separation. Results are presented from the extensive studies of these detectors in the CERN testbeams prior of installation and of the detector performance at LEP.

  1. Research of misalignment between dithered ring laser gyro angle rate input axis and dither axis

    NASA Astrophysics Data System (ADS)

    Li, Geng; Wu, Wenqi; FAN, Zhenfang; LU, Guangfeng; Hu, Shaomin; Luo, Hui; Long, Xingwu

    2014-12-01

    The strap-down inertial navigation system (SINS), especially the SINS composed by dithered ring laser gyroscope (DRLG) is a kind of equipment, which providing high reliability and performance for moving vehicles. However, the mechanical dither which is used to eliminate the "Lock-In" effect can cause vibration disturbance to the INS and lead to dithering coupling problem in the inertial measurement unit (IMU) gyroscope triad, so its further application is limited. Among DRLG errors between the true gyro rotation rate and the measured rotation rate, the frequently considered one is the input axis misalignment between input reference axis which is perpendicular to the mounting surface and gyro angular rate input axis. But the misalignment angle between DRLG dither axis and gyro angular rate input axis is often ignored by researchers, which is amplified by dither coupling problem and that would lead to negative effects especially in high accuracy SINS. In order to study the problem more clearly, the concept of misalignment between DRLG dither axis and gyro angle rate input axis is researched. Considering the error of misalignment is of the order of 10-3 rad. or even smaller, the best way to measure it is using DRLG itself by means of an angle exciter as an auxiliary. In this paper, the concept of dither axis misalignment is explained explicitly firstly, based on this, the frequency of angle exciter is induced as reference parameter, when DRLG is mounted on the angle exciter in a certain angle, the projections of angle exciter rotation rate and mechanical oscillation rate on the gyro input axis are both sensed by DRLG. If the dither axis has misalignment error with the gyro input axis, there will be four major frequencies detected: the frequency of angle exciter, the dither mechanical frequency, sum and difference frequencies of the former two frequencies. Then the amplitude spectrum of DRLG output signal obtained by the using LabVIEW program. if there are only angle exciter and the dither mechanical frequencies, the misalignment may be too small to be detected, otherwise, the amplitude of the sum and difference frequencies will show the misalignment angle between the gyro angle rate input axis and the dither axis. Finally, some related parameters such as frequency and amplitude of the angle exciter and sample rate are calculated and the results are analyzed. The simulation and experiment result prove the effectiveness of the proposed method..

  2. Phase Angle Effects on 3 ?m Absorption Band on Ceres: Implications for Dawn Mission

    NASA Astrophysics Data System (ADS)

    Takir, D.; Reddy, V.; Sanchez, J. A.; Le Corre, L.; Hardersen, P. S.; Nathues, A.

    2015-05-01

    Phase angle-induced spectral effects are important to characterize since they affect spectral band parameters such as band depth and band center, and therefore skew mineralogical interpretations of planetary bodies via reflectance spectroscopy. Dwarf planet (1) Ceres is the next target of NASA’s Dawn mission, which is expected to arrive in 2015 March. The visible and near-infrared mapping spectrometer (VIR) on board Dawn has the spatial and spectral range to characterize the surface between 0.25–5.0 ?m. Ceres has an absorption feature at 3.0 ?m due to hydroxyl- and/or water-bearing minerals. We analyzed phase angle-induced spectral effects on the 3 ?m absorption band on Ceres using spectra measured with the long-wavelength cross-dispersed (LXD: 1.9–4.2 ?m) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility. Ceres LXD spectra were measured at different phase angles ranging from 0.°7 to 22°. We found that the band center slightly increases from 3.06 ?m at lower phase angles (0.°7 and 6°) to 3.07 ?m at higher phase angles (11° and 22°), the band depth decreases by ?20% from lower phase angles to higher phase angles, and the band area decreases by ?25% from lower phase angles to higher phase angles. Our results will have implications for constraining the abundance of OH on the surface of Ceres from VIR spectral data, which will be acquired by Dawn starting spring 2015.

  3. Biometric gonioscopy and the effects of age, race, and sex on the anterior chamber angle

    PubMed Central

    Congdon, N G; Foster, P J; Wamsley, S; Gutmark, J; Nolan, W; Seah, S K; Johnson, G J; Broman, A T

    2002-01-01

    Aim: To utilise a novel method for making measurements in the anterior chamber in order to compare the anterior chamber angles of people of European, African, and east Asian descent aged 40 years and over. Methods: A cross sectional study on 15 people of each sex from each decade from the 40s to the 70s, from each of three racial groups—black, white, and Chinese Singaporeans. Biometric gonioscopy (BG) utilises a slit lamp mounted reticule to make measurements from the apparent iris insertion to Schwalbe's line through a Goldmann one mirror goniolens. The main outcome measures were BG measurements of the anterior chamber angle as detailed above. Results: There was no significant difference in angle measurement between black, white, and Chinese races in this study. However, at younger ages people of Chinese race appeared to have deeper angles than white or black people, whereas the angles of older Chinese were significantly narrower (p = 0.004 for the difference in slope of BG by age between Chinese and both black and white people). Conclusion: The failure to detect a difference in angle measurements between these groups was surprising, given the much higher prevalence of angle closure among Chinese. It appears that the overall apparent similarity of BG means between Chinese and Western populations may mask very different trends with age. The apparently more rapid decline in angle width measurements with age among Chinese may be due to the higher prevalence of cataract or “creeping angle closure.” However, longitudinal inferences from cross sectional data are problematic, and this may represent a cohort phenomenon caused by the increasing prevalence of myopia in the younger Singaporean population. PMID:11801496

  4. Junctional angle of a bihanded helix.

    PubMed

    Yang, Jing; Wolgemuth, Charles W; Huber, Greg

    2014-10-01

    Helical filaments having sections of reversed chirality are common phenomena in the biological realm. The apparent angle between the two sections of opposite handedness provides information about the geometry and elasticity of the junctional region. In this paper, the governing differential equations for the local helical axis are developed, and asymptotic solutions of the governing equations are solved by perturbation theory. The asymptotic solutions are compared with the corresponding numerical solutions, and the relative error at second order is found to be less than 1.5% over a range of biologically relevant curvature and torsion values from 0 to 1/2 in dimensionless units. PMID:25375538

  5. Junctional angle of a bihanded helix

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Wolgemuth, Charles W.; Huber, Greg

    2014-10-01

    Helical filaments having sections of reversed chirality are common phenomena in the biological realm. The apparent angle between the two sections of opposite handedness provides information about the geometry and elasticity of the junctional region. In this paper, the governing differential equations for the local helical axis are developed, and asymptotic solutions of the governing equations are solved by perturbation theory. The asymptotic solutions are compared with the corresponding numerical solutions, and the relative error at second order is found to be less than 1.5% over a range of biologically relevant curvature and torsion values from 0 to 1/2 in dimensionless units.

  6. Regge calculus from a new angle

    E-print Network

    Benjamin Bahr; Bianca Dittrich

    2009-07-24

    In Regge calculus space time is usually approximated by a triangulation with flat simplices. We present a formulation using simplices with constant sectional curvature adjusted to the presence of a cosmological constant. As we will show such a formulation allows to replace the length variables by 3d or 4d dihedral angles as basic variables. Moreover we will introduce a first order formulation, which in contrast to using flat simplices, does not require any constraints. These considerations could be useful for the construction of quantum gravity models with a cosmological constant.

  7. Narrow-angle Astrometry with SUSI

    NASA Astrophysics Data System (ADS)

    Kok, Y.; Ireland, M. J.; Robertson, J. G.; Tuthill, P. G.; Warrington, B. A.; Tango, W. J.

    2014-09-01

    SUSI (Sydney University Stellar Interferometer) is currently being fitted with a 2nd beam combiner, MUSCA (Micro-arcsecond University of Sydney Companion Astrometry), for the purpose of narrow-angle astrometry. With an aim to achieve ˜10 micro-arcseconds of angular resolution at its best, MUSCA allows SUSI to search for planets around bright binary stars, which are its primary targets. While the first beam combiner, PAVO (Precision Astronomical Visible Observations), is used to track stellar fringes during an observation, MUSCA will be used to measure separations of binary stars. MUSCA is a Michelson interferometer and its setup at SUSI will be described in this poster.

  8. Effects of the ankle angle of an ankle foot orthosis on foot pressure during the gait in healthy adults.

    PubMed

    Chang, Jong-Sung; Lee, Hae-Yong; Kim, Myoung-Kwon

    2015-04-01

    [Purpose] The purpose of this study was to investigate the effects of the ankle angle of an ankle foot orthosis (AFO) on foot pressure during the gait in healthy adults. [Subjects] Sixteen healthy males with neither orthopedic nor neurological problems participated in this study. [Methods] Subjects walked on a walkway at a self-selected pace with an AFO set at four different ankle angles (-5°, 0°, 5°, and 10°). Foot pressure was measured randomly according to the ankle angle of the AFO using an F-scan system. Three trials were measured and averaged for data analysis. [Results] The peak foot pressure of the hallux, 2nd-5th toes, 2nd and 3rd metatarsal heads, 4th and 5th metatarsal heads, and the heel showed significant differences among the AFO ankle angles: angles of 0° and -5° increased the foot pressure of the lateral legions, and the peak foot pressure of the heel at an AFO ankle angle of 10° was significantly greater than those of the other angles. [Conclusion] The ankle angle of the AFO affected foot pressure and gait patterns during gait. The results suggest that the appropriate angle for an AFO is between 5° and 10° when AFOs are prescribed by clinicians. PMID:25995549

  9. POINTES MTALLIQUES (TUNGSTNE) AYANT DIFFRENTS ANGLES DE CNE

    E-print Network

    Paris-Sud XI, Université de

    microscope is used. An electrolytic method of obtaining conical points of different angles is described surface et la diffusion de surface. En outre, si on utilise des pointes à angle de cône relativement petit

  10. Effects of dipole tilt angle on geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Nowada, M.; Shue, J.-H.; Russell, C. T.

    2009-09-01

    The relationship between the orientation of the interplanetary magnetic field (IMF), represented by the clock angle which is the angle defined by IMF-By and -Bz components, and the AL and AU indices is examined at various dipole tilt angles for the period of 1978-1988. We use the IMF data obtained from the IMP 8 satellite, AL and AU indices with corrected seasonal variations, and the dipole tilt angle, which is the dipole magnetic latitude of the subsolar point calculated as a function of the day of year and universal time. For both positive (dipole tilted to the Sun) and negative dipole tilt angles, the values of |AL| and AU decrease as the IMF clock angle moves away from 180?, becoming more northward. The indices also tend to become smaller for larger dipole tilt angle, either toward or away from the Sun. This dependence on dipole tilt angle enhances the semiannual variation of geomagnetic activity.

  11. Alternative IR geometries for TESLA with a small crossing angle

    E-print Network

    R. Appleby; D. Angal-Kalinin; P. Bambade; B. Mouton; O. Napoly; J. Payet; the TESLA Collaboration

    2005-01-24

    The formulation of hybrid crossing angle schemes has been a recent development of the TESLA collision geometry debate. Here we report on two such schemes, characterised by either a small vertical or horizontal beam crossing angle.

  12. Artificial neural networks for dihedral angles prediction in enzyme loops: a novel approach.

    PubMed

    Al-Gharabli, Samer I; Al-Agtash, Salem; Rawashdeh, Nathir A; Barqawi, Khaled R

    2015-01-01

    Structure prediction of proteins is considered a limiting step and determining factor in drug development and in the introduction of new therapies. Since the 3D structures of proteins determine their functionalities, prediction of dihedral angles remains an open and important problem in bioinformatics, as well as a major step in discovering tertiary structures. This work presents a method that predicts values of the dihedral angles ? and ? for enzyme loops based on data derived from amino acid sequences. The prediction of dihedral angles is implemented through a neural network based mining mechanism. The amino acid sequence data represents 6342 enzyme loop chains with 18,882 residues. The initial neural network input was a selection of 115 features and the outputs were the predicted dihedral angles ? and ?. The simulation results yielded a 0.64 Pearson's correlation coefficient. After feature selection through determining insignificant features, the input feature vector size was reduced to 45, while maintaining close to identical performance. PMID:25786794

  13. Simultaneous Soft Sensing of Tissue Contact Angle and Force for Millimeter-scale Medical Robots

    PubMed Central

    Arabagi, Veaceslav; Gosline, Andrew; Wood, Robert J.; Dupont, Pierre E.

    2013-01-01

    A novel robotic sensor is proposed to measure both the contact angle and the force acting between the tip of a surgical robot and soft tissue. The sensor is manufactured using a planar lithography process that generates microchannels that are subsequently filled with a conductive liquid. The planar geometry is then molded onto a hemispherical plastic scaffolding in a geometric configuration enabling estimation of the contact angle (angle between robot tip tangent and tissue surface normal) by the rotation of the sensor around its roll axis. Contact force can also be estimated by monitoring the changes in resistance in each microchannel. Bench top experimental results indicate that, on average, the sensor can estimate the angle of contact to within ±2° and the contact force to within ±5.3 g. PMID:24241496

  14. Atomic-resolution defect contrast in low angle annular dark-field STEM

    SciTech Connect

    Phillips, Patrick J.; De Graef, M.; Kovarik, Libor; Agrawal, A.; Windl, W.; Mills, M. J.

    2012-05-01

    While traditional high-resolution STEM is performed by exclusively collecting electrons which have been scattered to high angles (i.e., HAADF), the present contribution will focus on small-angle scattered electrons, as in low angle annular dark-field (LAADF) STEM. This unique imaging mode allows one to image defect contrast while maintaining directly interpretable atomic resolution. By simply adjusting the microscope camera length, and thus the acceptance angle of the annular detector, it is possible to transition between Z-contrast and defect contrast. Both LAADF and HAADF experimental and computational results are discussed in regards to zone axis imaging of a y/y1Ni-superalloy; various length scales are explored. Electron de-channeling is observed while the probe is placed over defected regions of crystal.

  15. Influence of blade angle distribution along leading edge on cavitation performance of a centrifugal pump

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Tan, L.; Cao, S. L.; Wang, Y. C.; Meng, G.; Qu, W. S.

    2015-01-01

    The influence of blade angle distribution along leading edge on cavitation performance of centrifugal pumps is analysed in the present paper. Three sets of blade angle distribution along leading edge for three blade inlet angles are chosen to design nine centrifugal pump impellers. The RNG k-epsilon turbulence model and the Zwart-Gerber-Belamri cavitation model are employed to simulate the cavitation flows in centrifugal pumps with different impellers and the same volute. The numerical results are compared with the experimental data, and the comparison proves that the numerical simulation can accurately predict the cavitation performance of centrifugal pumps. On the basis of the numerical simulations, the pump head variations with pump inlet pressure, and the flow details in centrifugal pump are revealed to demonstrate the influence of blade angle distribution along leading edge on cavitation performances of centrifugal pumps.

  16. Determination of Sun Angles for Observations of Shock Waves on a Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Haering, Edward A., Jr.; Noffz, Gregory K.; Aguilar, Juan I.

    1998-01-01

    Wing compression shock shadowgraphs were observed on two flights during banked turns of an L-1011 aircraft at a Mach number of 0.85 and an altitude of 35,000 ft (10,700 m). Photos and video recording of the shadowgraphs were taken during the flights to document the shadowgraphs. Bright sunlight on the aircraft was required. The time of day, aircraft position, speed and attitudes were recorded to determine the sun azimuth and elevation relative to the wing quarter chord-line when the shadowgraphs were visible. Sun elevation and azimuth angles were documented for which the wing compression shock shadowgraphs were visible. The shadowgraph was observed for high to low elevation angles relative to the wing, but for best results high sun angles relative to the wing are desired. The procedures and equations to determine the sun azimuth and elevation angle with respect to the quarter chord-line is included in the Appendix.

  17. Prediction of unsteady blade surface pressures on an advanced propeller at an angle of attack

    NASA Technical Reports Server (NTRS)

    Nallasamy, M.; Groeneweg, J. F.

    1989-01-01

    The paper considers the numerical solution of the unsteady, three-dimensional, Euler equations to obtain the blade surface pressures of an advanced propeller at an angle of attack. The specific configuration considered is the SR7L propeller at cruise conditions with a 4.6 deg inflow angle corresponding to the +2 deg nacelle tilt of the Propeller Test Assessment (PTA) flight test condition. The results indicate nearly sinusoidal response of the blade loading, with angle of attack. For the first time, detailed variations of the chordwise loading as a function of azimuthal angle are presented. It is observed that the blade is lightly loaded for part of the revolution and shocks appear from hub to about 80 percent radial station for the highly loaded portion of the revolution.

  18. Prediction of Unsteady Blade Surface Pressures on an Advanced Propeller at an Angle of Attack

    NASA Technical Reports Server (NTRS)

    Nallasamy, M.; Groeneweg, J. F.

    1989-01-01

    The numerical solution of the unsteady, three-dimensional, Euler equations is considered in order to obtain the blade surface pressures of an advanced propeller at an angle of attack. The specific configuration considered is the SR7L propeller at cruise conditions with a 4.6 deg inflow angle corresponding to the plus 2 deg nacelle tilt of the Propeller Test Assessment (PTA) flight test condition. The results indicate nearly sinusoidal response of the blade loading, with angle of attack. For the first time, detailed variations of the chordwise loading as a function of azimuthal angle are presented. It is observed that the blade is lightly loaded for part of the revolution and shocks appear from hub to about 80 percent radial station for the highly loaded portion of the revolution.

  19. Multiple incidence angle SIR-B experiment over Argentina Stereo-radargrammetric analysis

    NASA Technical Reports Server (NTRS)

    Leberl, F.; Domik, G.; Raggam, J.; Cimino, J.; Kobrick, M.

    1986-01-01

    Four overlapping Shuttle Imaging Radar-B (SIR-B) radar images were obtained across southern Argentina; these form a total of six stereo models with intersection angles ranging from 5 to 23 deg. This data set is uniquely suited for experimental evaluation of some basic assumptions on stereo-radargrammetry. Each stereo model was measured on a specially programmed photogrammetric analytical plotter; the resulting coordinates of ground points were compared with those from maps. It is concluded that accuracies are lower than expected at the larger stereo-intersection angles, amounting to about + or 60 m in each coordinate direction. This might be explained by limitations of the quality of stereofusion caused by look angle differences and specular point migration, backscatter differences due to different incidence angles, differences in azimuth directions, and image noise and speckle.

  20. Numerical investigation on properties of attack angle for an opposing jet thermal protection system

    NASA Astrophysics Data System (ADS)

    Lu, Hai-Bo; Liu, Wei-Qiang

    2012-08-01

    The three-dimensional Navier—Stokes equation and the k-in viscous model are used to simulate the attack angle characteristics of a hemisphere nose-tip with an opposing jet thermal protection system in supersonic flow conditions. The numerical method is validated by the relevant experiment. The flow field parameters, aerodynamic forces, and surface heat flux distributions for attack angles of 0°, 2°, 5°, 7°, and 10° are obtained. The detailed numerical results show that the cruise attack angle has a great influence on the flow field parameters, aerodynamic force, and surface heat flux distribution of the supersonic vehicle nose-tip with an opposing jet thermal protection system. When the attack angle reaches 10°, the heat flux on the windward generatrix is close to the maximal heat flux on the wall surface of the nose-tip without thermal protection system, thus the thermal protection has failed.

  1. Angles Formed by Parallel Lines and a Transversal

    NSDL National Science Digital Library

    Mrs. Brown

    2007-10-19

    In this lesson you will learn how to classify angles formed by parallel lines and a transversal as well as how to find the measures of these angles. You have proably heard of parallel lines but you proably don\\'t know about all the special angles that are formed when a line intersects a set of parallel lines. Click on the lecture below to learn about these special angles. The lecture has sound so make sure your ...

  2. Skeletal and Dental Effects of Maxillary Protraction in Patients with Angle Class III Malocclusion

    Microsoft Academic Search

    Andreas Jäger; Bert Braumann; Christian Kim; Susanne Wahner

    2001-01-01

    The aim of this study was a quantitative review of the published results concerning the treatment effects of maxillary protraction in patients with Angle Class III using the meta-analysis method. 85 articles published between 1966 and 1998 were reviewed under strict, pre-defined criteria. Of these, 12 studies presenting results of cephalometric measurements were selected for further analysis. The results of

  3. Effects of stance angle on postural stability and performance with national-standard air pistol competitors.

    PubMed

    Hawkins, Richard Nelson

    2013-01-01

    The effects of stance angle on postural stability and shooting processes were studied using eight national-standard male air-pistol shooters. Each shooter performed 60 shots each in four stance angles (0°, 15°, 30° and 45° from the line of fire). Postural stability was determined by measuring change in centre of pressure with a dual-force platform system assessing centre-of-pressure (COP) excursion (average difference of the centre of pressure from the mean) and COP speed (total COP path divided by time). Shooting process measures were determined by using a NOPTEL ST-2000 optoelectronic system. Score was assessed with a Sius Ascor S10 electronic scoring system. The results revealed no significant difference among the various stance angles; COP excursion or COP speed, p>0.05. Results indicated a significant stance angle effect with the shooting process measure, hit fine (percentage of hold within an area the size of the 10-ring when centred over the actual shot; p = 0.025) and the shooting performance measure adjusted score (raw score adjusted for true zero; p=0.008). Moreover, best overall performance was with a stance angle of 15°. These findings suggest that stance angle may affect pistol stability and performance in air-pistol athletes. PMID:24050465

  4. Influence of blade outlet angle on performance of low-specific-speed centrifugal pump

    NASA Astrophysics Data System (ADS)

    Cui, Baoling; Wang, Canfei; Zhu, Zuchao; Jin, Yingzi

    2013-04-01

    In order to analyze the influence of blade outlet angle on inner flow field and performance of low-specific-speed centrifugal pump, the flow field in the pump with different blade outlet angles 32.5° and 39° was numerically calculated. The external performance experiment was also carried out on the pump. Based on SIMPLEC algorithm, time-average N-S equation and the rectified k-? turbulent model were adopted during the process of computation. The distributions of velocity and pressure in pumps with different blade outlet angles were obtained by calculation. The numerical results show that backflow areas exist in the two impellers, while the inner flow has a little improvement in the impeller with larger blade outlet angle. Blade outlet angle has a certain influence on the static pressure near the long-blade leading edge and tongue, but it has little influence on the distribution of static pressure in the passages of impeller. The experiment results show that the low-specific-speed centrifugal pump with larger blade outlet angle has better hydraulic performance.

  5. Large Angle Transient Dynamics (LATDYN) user's manual

    NASA Technical Reports Server (NTRS)

    Abrahamson, A. Louis; Chang, Che-Wei; Powell, Michael G.; Wu, Shih-Chin; Bingel, Bradford D.; Theophilos, Paula M.

    1991-01-01

    A computer code for modeling the large angle transient dynamics (LATDYN) of structures was developed to investigate techniques for analyzing flexible deformation and control/structure interaction problems associated with large angular motions of spacecraft. This type of analysis is beyond the routine capability of conventional analytical tools without simplifying assumptions. In some instances, the motion may be sufficiently slow and the spacecraft (or component) sufficiently rigid to simplify analyses of dynamics and controls by making pseudo-static and/or rigid body assumptions. The LATDYN introduces a new approach to the problem by combining finite element structural analysis, multi-body dynamics, and control system analysis in a single tool. It includes a type of finite element that can deform and rotate through large angles at the same time, and which can be connected to other finite elements either rigidly or through mechanical joints. The LATDYN also provides symbolic capabilities for modeling control systems which are interfaced directly with the finite element structural model. Thus, the nonlinear equations representing the structural model are integrated along with the equations representing sensors, processing, and controls as a coupled system.

  6. Reactor mixing angle from hybrid neutrino masses

    NASA Astrophysics Data System (ADS)

    Sierra, D. Aristizabal; de Medeiros Varzielas, I.

    2014-07-01

    In terms of its eigenvector decomposition, the neutrino mass matrix (in the basis where the charged lepton mass matrix is diagonal) can be understood as originating from a tribimaximal dominant structure with small deviations, as demanded by data. If neutrino masses originate from at least two different mechanisms, referred to as "hybrid neutrino masses", the experimentally observed structure naturally emerges provided one mechanism accounts for the dominant tribimaximal structure while the other is responsible for the deviations. We demonstrate the feasibility of this picture in a fairly model-independent way by using lepton-number-violating effective operators, whose structure we assume becomes dictated by an underlying A 4 flavor symmetry. We show that if a second mechanism is at work, the requirement of generating a reactor angle within its experimental range always fixes the solar and atmospheric angles in agreement with data, in contrast to the case where the deviations are induced by next-to-leading order effective operators. We prove this idea is viable by constructing an A 4-based ultraviolet completion, where the dominant tribimaximal structure arises from the type-I seesaw while the subleading contribution is determined by either type-II or type-III seesaw driven by a non-trivial A 4 singlet (minimal hybrid model). After finding general criteria, we identify all the N symmetries capable of producing such A 4-based minimal hybrid models.

  7. RF sheaths for arbitrary B field angles

    NASA Astrophysics Data System (ADS)

    D'Ippolito, Daniel; Myra, James

    2014-10-01

    RF sheaths occur in tokamaks when ICRF waves encounter conducting boundaries and accelerate electrons out of the plasma. Sheath effects reduce the efficiency of ICRF heating, cause RF-specific impurity influxes from the edge plasma, and increase the plasma-facing component damage. The rf sheath potential is sensitive to the angle between the B field and the wall, the ion mobility and the ion magnetization. Here, we obtain a numerical solution of the non-neutral rf sheath and magnetic pre-sheath equations (for arbitrary values of these parameters) and attempt to infer the parametric dependences of the Child-Langmuir law. This extends previous work on the magnetized, immobile ion regime. An important question is how the rf sheath voltage distributes itself between sheath and pre-sheath for various B field angles. This will show how generally previous estimates of the rf sheath voltage and capacitance were reasonable, and to improve the RF sheath BC. Work supported by US DOE grants DE-FC02-05ER54823 and DE-FG02-97ER54392.

  8. Angle-resolved polarimetry measurements of antenna-mediated fluorescence

    E-print Network

    Mohtashami, Abbas; Koenderink, A Femius

    2015-01-01

    Optical phase-array antennas can be used to control not only the angular distribution but also the polarization of fluorescence from quantum emitters. The emission pattern of the resulting system is determined by the properties of the antenna, the properties of the emitters and the strength of the antenna-emitter coupling. Here we show that Fourier polarimetry can be used to characterize these three contributions. To this end, we measured the angle and Stokes-parameter resolved emission of bullseye plasmon antennas as well as spiral antennas excited by an ensemble of emitters. We estimate the antenna-emitter coupling on basis of the degree of polarization, and determine the effect of anisotropy in the intrinsic emitter orientation on polarization of the resulting emission pattern. Our results not only provide new insights in the behavior of bullseye and spiral antennas, but also demonstrate the potential of Fourier polarimetry when characterizing antenna mediated fluorescence.

  9. Jacobian for conversion from Euler Angles to Quaternions

    E-print Network

    Roumeliotis, Stergios I.

    Jacobian for conversion from Euler Angles to Quaternions Nikolas Trawny and Stergios Roumeliotis-0572 URL: http://www.cs.umn.edu/~trawny #12;Jacobian for conversion from Euler Angles to Quaternions the Jacobian needed for error conversion when changing from Euler angles to quaternion based attitude

  10. Real-Time Security Assessment of Angle Stability Using Synchrophasors

    E-print Network

    Real-Time Security Assessment of Angle Stability Using Synchrophasors Final Project Report Power 1996 PSERC #12;Real-Time Security Assessment of Angle Stability and Voltage Stability Using Engineering Research Center (PSERC) re- search project S-31, titled "Real-Time Security Assessment of Angle

  11. Cubic Equations and the Ideal Trisection of the Arbitrary Angle

    ERIC Educational Resources Information Center

    Farnsworth, Marion B.

    2006-01-01

    In the year 1837 mathematical proof was set forth authoritatively stating that it is impossible to trisect an arbitrary angle with a compass and an unmarked straightedge in the classical sense. The famous proof depends on an incompatible cubic equation having the cosine of an angle of 60 and the cube of the cosine of one-third of an angle of 60 as…

  12. Spray coating of superhydrophobic and angle-independent coloured films.

    PubMed

    Ge, Dengteng; Yang, Lili; Wu, Gaoxiang; Yang, Shu

    2014-03-01

    Angle-independent coloured films with superhydrophobicity were fabricated from quasi-amorphous arrays of monodispersed fluorinated silica nanoparticles via one-step spray coating. The film exhibited a high contact angle (>150°) and a low roll-off angle (~2°) and the colour could be tuned to blue, green and moccasin by varying the size of the nanoparticles. PMID:24457894

  13. Effect of liquid-solid contact angle on droplet evaporation

    Microsoft Academic Search

    S. Chandra; M. di Marzo; Y. M. Qiao; P. Tartarini

    1996-01-01

    The effect of varying initial liquid-solid contact angle on the evaporation of single droplets of water deposited on a stainless steel surface is studied using both experiments and numerical modeling. Contact angle is controlled in experiments by adding varying amounts] (100 and 1000 ppm) of a surfactant to water. The evolution of contact angle and liquid-solid contact diameter is measured

  14. Variable angle laser drilling of thermal barrier coated nimonic

    Microsoft Academic Search

    J Kamalu; P Byrd; A Pitman

    2002-01-01

    This paper provides a comprehensive description and discussion of the problems that occur during angled percussion laser drilling of thermal barrier coated (TBC) nimonic. Laser parameter sets covering a broad range of energies and pulse widths were used to drill holes normal to and at a high angle of incidence (low glancing angle) to the material surface. The dimensional characteristics

  15. Angle-preserving Quantized Phase Embeddings Petros T. Boufounos

    E-print Network

    Boufounos, Petros T.

    Angle-preserving Quantized Phase Embeddings Petros T. Boufounos Mitsubishi Electric Research-valued projections of real-valued signals preserves in- formation about the angle, i.e., the correlation, between those signals. This information can be exploited to design quantized angle-preserving embeddings, which

  16. Thirty Meter Telescope Site Testing V: Seeing and Isoplanatic Angle

    NASA Astrophysics Data System (ADS)

    Skidmore, Warren; Els, Sebastian; Travouillon, Tony; Riddle, Reed; Schöck, Matthias; Bustos, Edison; Seguel, Juan; Walker, David

    2009-10-01

    In this article we present an analysis of the statistical and temporal properties of seeing and isoplanatic angle measurements obtained with combined Differential Image Motion Monitor (DIMM) and Multi-Aperture Scintillation Sensor (MASS) units at the Thirty Meter Telescope (TMT) candidate sites. For each of the five candidate sites we obtained multiyear, high-cadence, high-quality seeing measurements. These data allow for a broad and detailed analysis, giving us a good understanding of the characteristics of each of the sites. The overall seeing statistics for the five candidate sites are presented, broken into total seeing (measured by the DIMM), free-atmosphere seeing and isoplanatic angle (measured by the MASS), and ground-layer seeing (difference between the total and free-atmosphere seeing). We examine the statistical distributions of seeing measurements and investigate annual and nightly behavior. The properties of the seeing measurements are discussed in terms of the geography and meteorological conditions at each site. The temporal variability of the seeing measurements over timescales of minutes to hours is derived for each site. We find that each of the TMT candidate sites has its own strengths and weaknesses when compared against the other candidate sites. The results presented in this article form part of the full set of results that are used for the TMT site-selection process. This is the fifth article in a series discussing the TMT site-testing project.

  17. The effects of three different rear knee angles on kinematics in the sprint start.

    PubMed

    Milanese, C; Bertucco, M; Zancanaro, C

    2014-08-01

    The purpose of this study was to investigate the rear knee angle range in the set position that allows sprinters to reach greater propulsion on the rear block during the sprint start. Eleven university-track team sprinters performed the sprint start using three rear knee angle conditions: 90°, 115° and 135°. A motion capture system consisting of 8 digital cameras (250 Hz) was used to record kinematic parameters at the starting block phase and the acceleration phase. The following variables were considered: horizontal velocity of the centre of mass (COM), COM height, block time, pushing time on the rear block, percentage of pushing time on the rear block, force impulse, push-off angle and length of the first two strides. The main results show that first, horizontal block velocity is significantly greater at 90° vs 115° and 135° rear knee angle (p<0.05 and p<0.001 respectively) at block clearance and the first two strides; second, during the pushing phase, the percentage of pushing time of the rear leg is significantly greater at 90° vs 135° rear knee angle (p<0.01). No significant difference was found for block time among the conditions. These results indicate that block velocity is the main kinematic parameter affected by rear knee angle during the starting block phase and acceleration phase. Furthermore, the 90° rear knee angle allows for a better push-off of the rear leg than larger angles at the set position. The findings of this study provide some direction and useful practical advice in defining an efficient rear leg biomechanical configuration at the set position. PMID:25177099

  18. Incorporation of gantry angle correction for 3D dose prediction in intensity-modulated radiation therapy.

    PubMed

    Sumida, Iori; Yamaguchi, Hajime; Kizaki, Hisao; Aboshi, Keiko; Tsujii, Mari; Yamada, Yuji; Yagi, Masashi; Ogawa, Kazuhiko

    2015-05-01

    Pretreatment dose verification with beam-by-beam analysis for intensity-modulated radiation therapy (IMRT) is commonly performed with a gantry angle of 0° using a 2D diode detector array. Any changes in multileaf collimator (MLC) position between the actual treatment gantry angle and 0° may result in deviations from the planned dose. We evaluated the effects of MLC positioning errors between the actual treatment gantry angles and nominal gantry angles. A gantry angle correction (GAC) factor was generated by performing a non-gap test at various gantry angles using an electronic portal imaging device (EPID). To convert pixel intensity to dose at the MLC abutment positions, a non-gap test was performed using an EPID and a film at 0° gantry angle. We then assessed the correlations between pixel intensities and doses. Beam-by-beam analyses for 15 prostate IMRT cases as patient-specific quality assurance were performed with a 2D diode detector array at 0° gantry angle to determine the relative dose error for each beam. The resulting relative dose error with or without GAC was added back to the original dose grid for each beam. We compared the predicted dose distributions with or without GAC for film measurements to validate GAC effects. A gamma pass rate with a tolerance of 2%/2 mm was used to evaluate these dose distributions. The gamma pass rate with GAC was higher than that without GAC (P = 0.01). The predicted dose distribution improved with GAC, although the dosimetric effect to a patient was minimal. PMID:25742866

  19. THE EFFECTS OF THREE DIFFERENT REAR KNEE ANGLES ON KINEMATICS IN THE SPRINT START

    PubMed Central

    Bertucco, M.; Zancanaro, C.

    2014-01-01

    The purpose of this study was to investigate the rear knee angle range in the set position that allows sprinters to reach greater propulsion on the rear block during the sprint start. Eleven university-track team sprinters performed the sprint start using three rear knee angle conditions: 90°, 115° and 135°. A motion capture system consisting of 8 digital cameras (250 Hz) was used to record kinematic parameters at the starting block phase and the acceleration phase. The following variables were considered: horizontal velocity of the centre of mass (COM), COM height, block time, pushing time on the rear block, percentage of pushing time on the rear block, force impulse, push-off angle and length of the first two strides. The main results show that first, horizontal block velocity is significantly greater at 90° vs 115° and 135° rear knee angle (p<0.05 and p<0.001 respectively) at block clearance and the first two strides; second, during the pushing phase, the percentage of pushing time of the rear leg is significantly greater at 90° vs 135° rear knee angle (p<0.01). No significant difference was found for block time among the conditions. These results indicate that block velocity is the main kinematic parameter affected by rear knee angle during the starting block phase and acceleration phase. Furthermore, the 90° rear knee angle allows for a better push-off of the rear leg than larger angles at the set position. The findings of this study provide some direction and useful practical advice in defining an efficient rear leg biomechanical configuration at the set position. PMID:25177099

  20. Incorporation of gantry angle correction for 3D dose prediction in intensity-modulated radiation therapy

    PubMed Central

    Sumida, Iori; Yamaguchi, Hajime; Kizaki, Hisao; Aboshi, Keiko; Tsujii, Mari; Yamada, Yuji; Yagi, Masashi; Ogawa, Kazuhiko

    2015-01-01

    Pretreatment dose verification with beam-by-beam analysis for intensity-modulated radiation therapy (IMRT) is commonly performed with a gantry angle of 0° using a 2D diode detector array. Any changes in multileaf collimator (MLC) position between the actual treatment gantry angle and 0° may result in deviations from the planned dose. We evaluated the effects of MLC positioning errors between the actual treatment gantry angles and nominal gantry angles. A gantry angle correction (GAC) factor was generated by performing a non-gap test at various gantry angles using an electronic portal imaging device (EPID). To convert pixel intensity to dose at the MLC abutment positions, a non-gap test was performed using an EPID and a film at 0° gantry angle. We then assessed the correlations between pixel intensities and doses. Beam-by-beam analyses for 15 prostate IMRT cases as patient-specific quality assurance were performed with a 2D diode detector array at 0° gantry angle to determine the relative dose error for each beam. The resulting relative dose error with or without GAC was added back to the original dose grid for each beam. We compared the predicted dose distributions with or without GAC for film measurements to validate GAC effects. A gamma pass rate with a tolerance of 2%/2 mm was used to evaluate these dose distributions. The gamma pass rate with GAC was higher than that without GAC (P = 0.01). The predicted dose distribution improved with GAC, although the dosimetric effect to a patient was minimal. PMID:25742866

  1. Hip rotation angle is associated with frontal plane knee joint mechanics during running.

    PubMed

    Sakaguchi, Masanori; Shimizu, Norifumi; Yanai, Toshimasa; Stefanyshyn, Darren J; Kawakami, Yasuo

    2015-02-01

    Inability to control lower extremity segments in the frontal and transverse planes resulting in large knee abduction angle and increased internal knee abduction impulse has been associated with patellofemoral pain (PFP). However, the influence of hip rotation angles on frontal plane knee joint kinematics and kinetics remains unclear. The purpose of this study was to explore how hip rotation angles are related to frontal plane knee joint kinematics and kinetics during running. Seventy runners participated in this study. Three-dimensional marker positions and ground reaction forces were recorded with an 8-camera motion analysis system and a force plate while subjects ran along a 25-m runway at a speed of 4m/s. Knee abduction, hip rotation and toe-out angles, frontal plane lever arm at the knee, internal knee abduction moment and impulse, ground reaction forces and the medio-lateral distance from the ankle joint center to the center of pressure (AJC-CoP) were quantified. The findings of this study indicate that greater hip external rotation angles were associated with greater toe-out angles, longer AJC-CoP distances, smaller internal knee abduction impulses with shorter frontal plane lever arms and greater knee abduction angles. Thus, there appears to exist a conflict between kinematic and kinetic risk factors of PFP, and hip external rotation angle may be a key factor to control frontal plane knee joint kinematics and kinetics. These results may help provide an appropriate manipulation and/or intervention on running style to reduce the risk of PFP. PMID:25572723

  2. Calculation angle and amplitude spectrum of interferogram with FPGA

    NASA Astrophysics Data System (ADS)

    Liu, Jiaqing; Ding, Lei

    2013-08-01

    Historically,computationally-intensive data processing for space-borne instruments has heavily relied on groundbased processing system.But with recent advances in FPGAs such as Xilinx Virtex-4 and Virtex-5 series devices that including PowerPC processors and DSP blocks thereby provding a flexible hardware and software co-design architecture to meet computationally-intensive data processing need,So it is able to shift more processing on- board;for high data active and passive instruments,such as interferometer,Implementations of on-board processing algorithms to perform lossless data reductions can dramatically reduce the data rates,therefore relaxing the downlink data bandwidth requirements.The interferograms are performs the inverse fourier transform on-board in order to decrease the transmission rate.In [Revercomb et al.] paper show that only use the modulus of the complx spectrum will lead to big calibration errors.So the amplitude and angle of the complex spectrum is need for radiometric cablibration,but there have a big challenge for on board obtained the amplitude and angle of the complex spectrum.In this paper,we introduce the CORDIC algorithm to slove it. The CORDIC algorithm is an iterative convergence algorithm that performs a rotation iteratively using a series of specific incremental rotation angles selected so that each iteration is performed by shift and add operation,which fit for FPGA implementation,and can be parallel in a chip to fullfill different latency and throughput.Implemention results with Xilinx FPGA are summarized.

  3. Three-dimensional reconstruction method for measuring the knee valgus angle of the femur in northern Chinese adults.

    PubMed

    Liu, Tong; Wang, Chen-yu; Xiao, Jian-lin; Zhu, Lan-yu; Li, Xue-zhou; Qin, Yan-guo; Gao, Zhong-li

    2014-08-01

    The purpose of this study was to establish a method for measuring the knee valgus angle from the anatomical and mechanical axes on three-dimensional reconstruction imaging models, and to use this method for estimating an average knee valgus angle value for northern Chinese adults. Computed tomographic angiography data in DICOM format for 128 normal femurs from 64 adult subjects were chosen for analysis. After the femur images were subjected to three-dimensional reconstruction, the deepest point in the intercondylar notch (point A), the midpoint of the medullary cavity 20 cm above the knee-joint line (point B), and the landmark of the femoral head rotation center (point C) were identified on each three-dimensional model. The knee valgus angle was defined as the angle enclosed by the distal femoral anatomical axis (line AB) and the femoral mechanical axis (line AC). The average (mean±SD) of knee valgus angle for the 128 femurs was 6.20°±1.20° (range, 3.05° to 10.64°). Significant positive correlations were found between the knee valgus angles of the right and left sides and between the knee valgus angle and age. During total knee arthroplasty, choosing a valgus cut angle of approximately 6° may achieve a good result in reestablishing the natural mechanical alignment of the lower extremity for patients of northern Chinese ethnicity. Larger valgus cut angles should be chosen for older patients. PMID:25091990

  4. Estimation of insertion depth angle based on cochlea diameter and linear insertion depth: a prediction tool for the CI422.

    PubMed

    Franke-Trieger, Annett; Mürbe, Dirk

    2014-11-01

    Beside the cochlear size, the linear insertion depth (LID) influences the insertion depth angle of cochlear implant electrode arrays. For the specific implant CI422 the recommended LID is not fixed but can vary continuously between 20 and 25 mm. In the current study, the influence of cochlea size and LID on the final insertion depth angle was investigated to develop a prediction tool for the insertion depth angle by means of cochlea diameter and LID. Preoperative estimation of insertion depth angles might help surgeons avoid exceeding an intended insertion depth, especially with respect to low-frequency residual hearing preservation. Postoperative, high-resolution 3D-radiographs provided by Flat Panel Computed Volume Tomography (FPCT) were used to investigate the insertion depth angle in 37 CI422 recipients. Furthermore, the FPCT images were used to measure linear insertion depth and diameter of the basal turn of the cochlea. A considerable variation of measured insertion depth angles ranging from 306° to 579° was identified. The measured linear insertion depth ranged from -18.6 to 26.2 mm and correlated positively with the insertion depth angle. The cochlea diameter ranged from 8.11 to 10.42 mm and correlated negatively with the insertion depth angle. The results suggest that preoperatively measured cochlea diameter combined with the option of different array positions by means of LID may act as predictors for the final insertion depth angle. PMID:25361895

  5. New comparative ultrasound biomicroscopic findings between fellow eyes of acute angle closure and glaucomatous eyes with narrow angle

    Microsoft Academic Search

    Rafael Vidal Mérula; Sebastião Cronemberger; Alberto Diniz Filho; Nassim Calixto

    2008-01-01

    Purpose: To compare morphometric features between fellow acute primary angle-closure (APAC) eyes and glaucomatous or suspect eyes with narrow angle (NA). Methods: Fellow eyes of 30 patients with unilateral APAC and 30 with NA were evaluated by ultrasound biomicroscopy (UBM) under light and dark conditions. UBM parameters such as anterior chamber depth (ACD), angle opening distance at 250 µm\\/500 µm

  6. Small-angle Compton Scattering to Determine the Depth of a Radioactive Source in Matter

    SciTech Connect

    Oberer, R. B.; Gunn, C. A.; Chiang, L. G.; Valiga, R. E.; Cantrell, J. A.

    2011-04-01

    A gamma-ray peak in a spectrum is often accompanied by a discontinuity in the Compton continuum at the peak. The Compton continuum results from Compton scattering in the detector. The discontinuity at a peak results from small-angle Compton scattering by the gamma rays in matter situated directly between the gamma-ray source and the detector. The magnitude of this discontinuity with respect to the gamma-ray peak is therefore an indicator of the amount of material or shielding between the gamma-ray source and the detector. This small-angle scattering was used to determine the depth of highly-enriched uranium (HEU) solution standards in a concrete floor mockup. The empirical results of the use of this small-angle scattering discontinuity in a concrete floor experiment will be described. A Monte Carlo calculation of the experiment will also be described. In addition, the depth determined from small-angle scattering was used in conjunction with differential attenuation to more accurately measure the uranium content of the mockup. Following these empirical results, the theory of small-angle scattering will be discussed. The magnitude of the discontinuity compared to the peak count rate is directly related to the depth of the gamma-ray source in matter. This relation can be described by relatively simple mathematical expressions. This is the first instance that we are aware of in which the small-angle Compton scattering has been used to determine the depth of a radioactive source. Furthermore this is the first development of the theoretical expressions for the magnitude of the small-angle scattering discontinuity.

  7. Euler angles, quaternions, and transformation matrices for space shuttle analysis

    NASA Technical Reports Server (NTRS)

    Henderson, D. M.

    1977-01-01

    Relationships between the Euler angles and the transformation matrix, the quaternion and the transformation matrix, and the Euler angles and the quaternion are analyzed, and equations developed are applied directly to current space shuttle problems. The twelve three-axis Euler transformation matrices as functions of the Euler angles, the equations for the quaternion as a function of the Euler angles, and the Euler angles as a function of the transformation matrix elements are included along with a group of utility subroutines to accomplish the Euler matrix, quaternion matrix, and Euler quaternion relationships.

  8. Incident Angle of Saltating Particles in Wind-Blown Sand

    PubMed Central

    Fu, Lin-Tao; Bo, Tian-Li; Gu, Hai-Hua; Zheng, Xiao-Jing

    2013-01-01

    Incident angle of saltating particles plays a very important role in aeolian events. In this paper, the incident angles of sand particles near the sand bed were measured in wind tunnel. It reveals that the incident angles range widely from 0° to 180° and thereby the means of angles are larger than published data. Surprisingly, it is found the proportion that angles of 5°–15° occupy is far below previous reports. The measuring height is probably the most important reason for the measurement differences between this study and previous investigations. PMID:23874470

  9. Impedance Scaling for Small Angle Transitions

    SciTech Connect

    Stupakov, G.; Bane, Karl; /SLAC; Zagorodnov, I.; /DESY; ,

    2010-10-27

    Based on the parabolic equation approach to Maxwell's equations we have derived scaling properties of the high frequency impedance/short bunch wakefields of structures. For the special case of small angle transitions we have shown the scaling properties are valid for all frequencies. Using these scaling properties one can greatly reduce the calculation time of the wakefield/impedance of long, small angle, beam pipe transitions, like one often finds in insertion regions of storage rings. We have tested the scaling with wakefield simulations of 2D and 3D models of such transitions, and found that the scaling works well. In modern ring-based light sources one often finds insertion devices having extremely small vertical apertures (on the order of millimeters) to allow for maximal undulator fields reaching the beam. Such insertion devices require that there be beam pipe transitions from these small apertures to the larger cross-sections (normally on the order of centimeters) found in the rest of the ring. The fact that there may be many such transitions, and that these transitions introduce beam pipe discontinuities very close to the beam path, means that their impedance will be large and, in fact, may dominate the impedance budget of the entire ring. To reduce their impact on impedance, the transitions are normally tapered gradually over a long distance. The accurate calculation of the impedance or wakefield of these long transitions, which are typically 3D objects (i.e. they do not have cylindrical symmetry), can be quite a challenging numerical task. In this report we present a method of obtaining the impedance of a long, small angle transition from the calculation of a scaled, shorter one. Normally, the actual calculation is obtained from a time domain simulation of the wakefield in the structure, where the impedance can be obtained by performing a Fourier transform. We shall see that the scaled calculation reduces the computer time and memory requirements significantly, especially for 3D problems, and can make the difference between being able to solve a problem or not. The method is based on the parabolic equation approach to solving Maxwell's equation developed in Refs. [1, 2].

  10. Structure analysis of regenerated cellulose hydrogels by small-angle and ultra-small-angle x-ray scattering.

    PubMed

    Ando, H; Konishi, T

    2000-07-01

    Absolute intensities Deltai(q) of small-angle x-ray scattering (SAXS) and ultra-small-angle x-ray scattering (USAXS) were measured in a wide range of scattering vector q from 2x10(-4) to 0.5 A(-1) for transparent (VI-P) and translucent (VI-L) cellulose hydrogels prepared by coagulation and regeneration of viscose in acid solutions with and without acetone, respectively. We obtained the scattering intensities at very small q conveniently by desmearing the combined data measured by SAXS and USAXS. The plot of Deltai(q)q(2) versus log(10) q showed a peak at -2.5results were consistent with those obtained by the wide-angle x-ray-diffraction measurement and also with the observation by scanning probe microscopy. PMID:11088527

  11. Structure analysis of regenerated cellulose hydrogels by small-angle and ultra-small-angle x-ray scattering

    NASA Astrophysics Data System (ADS)

    Ando, Hitoshi; Konishi, Toshiki

    2000-07-01

    Absolute intensities ?i(q) of small-angle x-ray scattering (SAXS) and ultra-small-angle x-ray scattering (USAXS) were measured in a wide range of scattering vector q from 2×10-4 to 0.5 Å-1 for transparent (VI-P) and translucent (VI-L) cellulose hydrogels prepared by coagulation and regeneration of viscose in acid solutions with and without acetone, respectively. We obtained the scattering intensities at very small q conveniently by desmearing the combined data measured by SAXS and USAXS. The plot of ?i(q)q2 versus log10 q showed a peak at -2.5results were consistent with those obtained by the wide-angle x-ray-diffraction measurement and also with the observation by scanning probe microscopy.

  12. Viewing angle dependence of speckle contrast ratio in laser projection system

    NASA Astrophysics Data System (ADS)

    Ma, Qianli; Xu, ChangQing; Ming, Hai

    2015-03-01

    The speckle, which is due to the interference of coherent light scattered by a random surface, can severely degrades the image quality. The speckle properties are usually measured by a camera, which takes images of the center of a projection screen. As a result, the effects of different viewing angles are not considered. In this paper, the dependence of speckle contrast ratio on the viewing angles in a laser projection system is studied. Two major effects have been considered in the studies. First, different viewing angles result different projection distances. Secondly, for a rough screen, there exists an angular intensity distribution for the reflected/scattered light, which is determined by the structure of the screen surface. By combining these two effects, the experiment results show that the speckle contrast can vary significantly for different viewing angels. It is found that speckle contrast decreases with increase of viewing angle. As a result, when evaluating the speckle contrast in a laser projection system, the dependence of viewing angle should be considered.

  13. Predicted upwash angles at engine inlets for STOL aircraft

    NASA Technical Reports Server (NTRS)

    Albers, J. A.

    1972-01-01

    Upwash angles were predicted for a STOL lifting system by using a two-dimensional potential flow analysis. Upwash angles are presented for distances ahead of the wing leading edge of 50, 75, and 100 percent of wing chord. The upwash angle was determined to be insensitive to the vertical location of the engine inlet. For a wide range of takeoff and landing conditions, the upwash angle was found to be a function of the total two-dimensional lift coefficient. Upwash angles, along with typical flow fields, are presented for a range of total two-dimensional lift coefficients from 2 to 12. Three-dimensional effects were considered in estimating upwash angles for an unswept-wing externally blown flap aircraft. For this STOL configuration, effective upwash angles during takeoff, approach, and waveoff conditions were found to be 22 deg, 26 deg, and 36 deg, respectively.

  14. Malocclusion Pattern (Angle's) in Mauritian Orthodontic Patients.

    PubMed

    Durgesh, B H; Prakash, Prashanth; Ramakrishnaiah, Ravikumar; Subashchandra Phulari, Basavaraj; Al Kheraif, Abdul Aziz A

    2012-01-01

    The aim of the study was to assess the pattern of malocclusion in different ethnic group of Mauritian population visiting the Orthodontic Department at Mauras College of Dentistry and Hospital, Republic of Mauritius. The study population comprised of 624 patients who visited the orthodontic department during 2010. The clinical examination was conducted by a well-calibrated orthodontist. The data were recorded in the case sheets and was analyzed for presence of angles class I, class II, and class III malocclusion in both male and female patients of Asian, African, Caucasian, and Chinese ethnicity aged 5-55 years. Malocclusion was found to be high in females compared to males. 414 patients (150 male?+?264 female) presented with class I, 182 patients (52 male?+?130 female) presented with class II, and 28 patients (12 male + 16 female) presented with class III. Asian ethnic group were more affected and patient seeking orthodontic treatment was high in 11-15 years age group. PMID:22655203

  15. Experimental Status of the CKM Angle Beta

    SciTech Connect

    Hirschauer, James F.; /Fermilab

    2012-04-12

    The authors summarize measurements of the CKM angle {beta} at the B-factories emphasizing a comparison of {beta} measured in the B{sup 0} {yields} c{bar c}K{sup (*)0} decay channels and {beta}{sub eff} measured in b {yields} q{bar q}s decay channels, such as B{sup 0} {yields} {omega}K{sub s}{sup 0}, B{sup 0} {yields} {eta}'K{sup 0}, B{sup 0} {yields} {pi}{sup 0}K{sub S}{sup 0}, and B{sup 0} {yields} s{sup 0} K{sub S}{sup 0}K{sub S}{sup 0}.

  16. Novel therapies for open-angle glaucoma

    PubMed Central

    Wentz, Scott M.; Kim, Nathaniel J.; Wang, Jenny; Amireskandari, Annahita; Siesky, Brent

    2014-01-01

    Open-angle glaucoma is a multifactorial optic neuropathy characterized by progressive loss of retinal ganglion cells and their axons. It is an irreversible disease with no established cure. The only currently approved treatment is aimed at lowering intraocular pressure, the most significant risk factor known to date. However, it is now clear that there are other risk factors involved in glaucoma's pathophysiology. To achieve future improvements in glaucoma management, new approaches to therapies and novel targets must be developed. Such therapies may include new tissue targets for lowering intraocular pressure, molecules influencing ocular hemodynamics, and treatments providing neuroprotection of retinal ganglion cells. Furthermore, novel drug delivery systems are in development that may improve patient compliance, increase bioavailability, and decrease adverse side effects. PMID:25580256

  17. The Spacelab Wide Angle Telescope (SWAT)

    NASA Technical Reports Server (NTRS)

    West, R. M.; Gull, T. R.; Henize, K. G.; Bertola, F.

    1979-01-01

    A fast wide angle telescope that will be capable of imaging to the darker sky limit and in the ultraviolet wavelength region available above the atmosphere is described. The telescope (SWAT) has a resolution comparable to that of the large ground-based Schmidt telescope and a field of at least five degrees. A number of astrophysically important investigations can only be accomplished with such a telescope, e.g., detection of hidden, hot objects like hot white dwarfs and subwarfs in stellar binary systems, and energetic regions in globular clusters and galaxy nuclei. It permits unique studies of the UV-morphology of extended objects and allows discovery of very faint extensions, halos, jets, and filaments in galaxies. It can contribute to the investigation of dust in the Milky Way and in other galaxies and, with an objective prism, spectra of very faint objects can be obtained. The SWAT will localize objects for further study with the narrow-field Space Telescope.

  18. Image Reconstruction With Limited View Angle Projections

    NASA Astrophysics Data System (ADS)

    Inouye, T.

    1982-11-01

    A new method for image reconstruction from smaller view angle projections less than 180 degrees, is reported. This method does not include any missing projection data estimating processes, which are often seriously jeopardized by the presence of a slight fluctuation component. In this algorithm, the projection function is expanded by using complete functions, which can compose an orthogonal set on the projection allowed data variable region. These orthogonal functions are analytically extended to the outside variable area, where the projection data are not available, and the whole object functions are obtained. Computer simulations were carried out to demonstrate the effectiveness of the method. Some practical algo-rithms for the real data calculations are also presented.

  19. Angle of Light Rays and Surface Distribution

    NSDL National Science Digital Library

    2012-08-03

    This experimental activity is designed to develop basic understanding of the relationship between the angle of light rays and the area over which the light rays are distributed, and the potential to affect changes in the temperature of materials. Resources needed to conduct this activity include a flashlight, cardboard, protractor and ruler. The resource includes background information, a pre-activity inquiry exploration for students, teaching tips and questions to guide student discussion. This is chapter 4 of Meteorology: An Educator's Resource for Inquiry-Based Learning for Grades 5-9. The guide includes a discussion of learning science, the use of inquiry in the classroom, instructions for making simple weather instruments, and more than 20 weather investigations ranging from teacher-centered to guided and open inquiry investigations.

  20. Small angle electron diffraction and deflection

    NASA Astrophysics Data System (ADS)

    Koyama, T.; Takayanagi, K.; Togawa, Y.; Mori, S.; Harada, K.

    2012-03-01

    Electron optical system is constructed in order to obtain small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 radian in the reciprocal space. Long-distance camera length up to 3000 m is achieved in a conventional transmission electron microscope with LaB6 thermal emission type. The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited in Permalloy elements. A simultaneous recording of electron diffraction and Lorentz deflection is also demonstrated in 180 degree striped magnetic domains of La0.825Sr0.175MnO3.

  1. High-angle-of-attack yawing moment asymmetry of the X-31 aircraft from flight test

    NASA Technical Reports Server (NTRS)

    Cobleigh, Brent R.

    1994-01-01

    Significant yawing moment asymmetries were encountered during the high-angle-of-attack envelope expansion of the two X-31 aircraft. These asymmetries led to position saturations of the thrust vector vanes and trailing-edge flaps during some of the dynamic stability axis rolling maneuvers at high angles of attack. This slowed the high-angle-of-attack envelope expansion and resulted in maneuver restrictions. Several aerodynamic modifications were made to the X-31 forebody with the goal of minimizing the asymmetry. A method for determining the yawing moment asymmetry from flight data was developed and an analysis of the various configuration changes completed. The baseline aircraft were found to have significant asymmetries above 45 deg angle of attack with the largest asymmetry typically occurring around 60 deg angle of attack. Applying symmetrical boundary layer transition strips along the forebody sides increased the magnitude of the asymmetry and widened the angle-of-attack range over which the largest asymmetry acted. Installing longitudinal forebody strakes and rounding the sharp nose of the aircraft caused the yawing moment asymmetry magnitude to be reduced. The transition strips and strakes made the asymmetry characteristic of the aircraft more repeatable than the clean forebody configuration. Although no geometric differences between the aircraft were known, ship 2 consistently had larger yawing moment asymmetries than ship 1.

  2. Asymmetrical Flow Simulation of Icing Effects in S-Duct Inlets at Angle of Attack

    NASA Astrophysics Data System (ADS)

    Jin, Wonjin; Taghavi, Ray R.; Farokhi, Saeed

    2011-04-01

    The effect of flow angularity on an S-duct inlet with icing is computationally investigated. Flow angularity is simulated through angle-of-attack, and sideslip in addition to asymmetrical ice accretion on the inlet lip. A commercial CFD code, STAR-CCM+ is used for the steadystate computations with the shear-stress transport (SST) k-? turbulence model. Symmetrical and asymmetrical glaze ice shapes are computationally simulated on the inlet lip. The symmetrical glaze ice uniformly covers the entire cowl lip; whereas the asymmetrical glaze ice is simulated on a 1/4 sector of the inlet lip and is positioned on top, bottom or side of the inlet lip. The results indicate that flow angularity, whether in angle-of-attack or sideslip, aggravates the low performance of inlets with icing. The total pressure recovery suffers an additional ~2% loss and the inlet mass flow rate drops by ~7% when the inlet is at +20° angle of attack, as compared to zero angle, for flight Mach number of 0.34. The extent of loss in total pressure and a drop in mass flow rate depends on the asymmetrical icing location as well as the inlet angle-of-attack and sideslip. In addition, the ice-induced flow blockage is identified as a critical inlet performance parameter, since the symmetrical (360°) glaze ice with its wider flow blockage creates a lower total pressure recovery than the asymmetrical (90°) glaze ice at all angles of attack or sideslip.

  3. Multi-azimuthal-angle effects in self-induced supernova neutrino flavor conversions without axial symmetry

    NASA Astrophysics Data System (ADS)

    Mirizzi, Alessandro

    2013-10-01

    The flavor evolution of neutrinos emitted by a supernova (SN) core is strongly affected by the refractive effects associated with the neutrino-neutrino interactions in the deepest stellar regions. Till now, all numerical studies have assumed the axial symmetry for the “multi-angle effects” associated with the neutrino-neutrino interactions. Recently, it has been pointed out in Raffelt, Sarikas, and Seixas [Phys. Rev. Lett. 111, 091101 (2013)] that if this assumption is removed, a new multi-azimuthal-angle (MAA) instability emerges in the flavor evolution of the dense SN neutrino gas, in addition to the one caused by multi-zenith-angle effects. Inspired by this result, for the first time we numerically solve the nonlinear neutrino propagation equations in SN, introducing the azimuthal angle as an angular variable in addition to the usual zenith angle. We consider simple energy spectra with an excess of ?e over ?¯e. We find that even starting with a complete axial symmetric neutrino emission, the MAA effects would lead to significant flavor conversions in normal mass hierarchy, in cases otherwise stable under the only multi-zenith-angle effects. The final outcome of the flavor conversions, triggered by the MAA instability, depends on the initial asymmetry between ?e and ?¯e spectra. If it is sufficiently large, final spectra would show an ordered behavior with spectral swaps and splits. Conversely, for small flavor asymmetries flavor decoherence among angular modes develops, also affecting the flavor evolution in the inverted mass hierarchy.

  4. Differences between the alpha angles measured manually and digitally from paediatric hip ultrasonograms.

    PubMed

    Sariyilmaz, Kerim; Saglam, Yavuz; Ozkunt, Okan; Yildiz, Fatih; Sungur, Mustafa; Hurmeydan, Onder Murat; Goksan, Suleyman Bora

    2015-07-01

    The aim of this study was to reveal whether a meaningful difference is caused by measuring the alpha angle in hip ultrasonography manually or digitally to help the early diagnosis and treatment of DDH and observe the treatment implications of any such difference. All ultrasound images were obtained by same orthopaedist, and each hip was measured twice by two investigators with different levels of experience. Standard images were taken, and a printout of the standard images were obtained. The alpha angle was measured digitally by using the sonography device. The alpha angle was also measured by pencil, ruler and goniometer on the printout after 2 days. One hundred and two hips of 51 babies, at a mean age of 14 weeks, were assessed. The mean alpha angle measured manually with a goniometer was 64.4° (±1.6°), while that measured on the ultrasonography device was 65.3° (±0.9°). This difference was found to be statistically different (p = 0.016). Typology changes occurred in a total of 10 hips out of 102 as a result of manual and digital measurements. However, this study showed reduction in alpha angle variation and considerable advantages for manual alpha angle measurement with pencil and goniometer on a printout compared to computer-based measurement; future studies are needed to understand these differences caused by each measurement method. PMID:25869106

  5. Effect of postural angle on back muscle activities in aging female workers performing computer tasks

    PubMed Central

    Kamil, Nabilla Sofia Mohd; Dawal, Siti Zawiah Md

    2015-01-01

    [Purpose] This study investigated the effects of postural angle on back muscle activity during a computer task in aging women. [Subjects] Seventeen women ?50?years old participated. [Methods] The participants were instructed to perform computer-related tasks for 20 minutes on a workstation that simulated typical office working conditions. Back posture was measured from the measured trunk and pelvic angles. Electromyography activities were recorded simultaneously from the cervical erector spinae, longissimus, and multifidus muscles. [Results] The lowest mean percentages of maximum voluntary contraction for the cervical erector spinae and longissimus muscles were obtained when the upper trunk and pelvic angles were between 0° to ?5° from the sagittal plane. The back muscle activities increased as the upper trunk and pelvic angles exceeded 0°. Statistical analysis showed significant correlations between upper trunk angle and cervical erector spinae and longissimus muscle activities. Similarly, pelvic angle was significantly correlated with cervical erector spinae and multifidus muscle activities. [Conclusion] A neutral back posture minimizes muscle activities in aging women performing computer tasks.

  6. Two-Frequency Paired Polarization Interferometer for Faraday Rotation Angle Detection

    NASA Astrophysics Data System (ADS)

    Lin, Chu-En; Chang, Jin-Gor; Chou, Li-Dek; Yu, Chih-Jen; Lee, Cheng-Chung; Chou, Chien

    2009-08-01

    A highly sensitive two-frequency paired linear polarized interferometer (TPPI) for measuring the Faraday rotation angle and Verdet constant of the Bi12SiO20 (BSO) crystal in real time was set up by an amplitude-sensitive detection method. TPPI features a common-path heterodyne interferometer in conjunction with a highly correlated paired linear polarized laser beam. Then, the antisymmetry of polarized heterodyne signals is produced and Faraday rotation angle detection by a balanced detector scheme is satisfied automatically. As a result, shot-noise-limited detection of Faraday rotation angle is possible. In addition, the Faraday rotation angle detection is also insensitive to the scattering and absorption caused by the specimen because of the common-path propagation of the paired linear polarized laser beam. Experimentally, the sensitivities of Faraday rotation angle and Verdet constant measurements of the BSO crystal under the arrangement with a single pass of the laser beam in TPPI are 4.93×10-5 rad/mm and 2.6×10-7 rad/(mT·mm), respectively. This suggests that the Faraday rotation angle detection sensitivity has the potential to be on the order of 10-8 rad/mm if a Fabry-Perot cavity with a finesse of F=120 is used in TPPI.

  7. A jamming strategy against synthetic aperture radar with varieties of squint angles and wide beams

    NASA Astrophysics Data System (ADS)

    Lin, Xiaohong; Xue, Guoyi; Liu, Peiguo

    2013-10-01

    In order to form a false scene in Synthetic Aperture Radar (SAR) image, deceptive jammer need to get the relevant SAR parameters. In these parameters, squint angle and beamwidth usally change and it will make the pre-generated jamming signal unuseful. For solving this problem, a strategy is proposed to transform the pre-generated jamming signals to counter SAR with arbitrary squint angle and beamwidth in real time. Firstly, the jamming effects under estimation errors of SAR's squint angle and beam-width are analyzed. Using Graphics Processing Units (GPU), a parallel algorithm to generate jamming signals for varying squint angle and azimuth beam-width is proposed. Then, This paper describes a method that can implement the signal transformation between wide-beam condition and narrow-beam condition. Based on the generated signals, the jamming under arbitrary squint angle and beam-width can be realized in real time. The simulation results shows that this strategy is effective to jam SAR with varieties of squint angles and wide-beams.

  8. Gonioscopy findings and prevalence of occludable angles in a Burmese population: the Meiktila Eye Study

    PubMed Central

    Casson, R J; Newland, H S; Muecke, J; McGovern, S; Abraham, L M; Shein, W K; Selva, D; Aung, T

    2007-01-01

    Aim To determine the prevalence of preglaucomatous angle?closure disease in central Myanmar. Methods A population?based survey of inhabitants ?40?years in the Meiktila District was carried out; 2481 subjects were identified, 2076 participated and 2060 underwent gonioscopy of at least one eye. Eyes with angles traditionally described as “occludable” were recorded as primary angle?closure suspects (PACS); eyes with PACS and peripheral anterior synechiae (PAS), or an increased intraocular pressure but without primary angle?closure glaucoma, were recorded as primary angle closure (PAC). Results The prevalence of PACS in at least one eye was 5.7% (95% CI 4.72 to 6.62); prevalence increased with age and was more common in women (p<0.001). The prevalence of PAC in at least one eye was 1.50% (95% CI 1.47 to 1.53). All participants with PAS had at least 90° of closure (range 90–360°). Conclusion The prevalence of preglaucomatous angle?closure disease (PACS and PAC) in this population was 5.7% and 1.5%, respectively. PACS was more common in women, and its prevalence increased with age. PMID:17576708

  9. Prediction of unsteady airfoil flows at large angles of incidence

    NASA Technical Reports Server (NTRS)

    Cebeci, Tuncer; Jang, H. M.; Chen, H. H.

    1992-01-01

    The effect of the unsteady motion of an airfoil on its stall behavior is of considerable interest to many practical applications including the blades of helicopter rotors and of axial compressors and turbines. Experiments with oscillating airfoils, for example, have shown that the flow can remain attached for angles of attack greater than those which would cause stall to occur in a stationary system. This result appears to stem from the formation of a vortex close to the surface of the airfoil which continues to provide lift. It is also evident that the onset of dynamic stall depends strongly on the airfoil section, and as a result, great care is required in the development of a calculation method which will accurately predict this behavior.

  10. Target pitch angle for the microburst escape maneuver

    NASA Technical Reports Server (NTRS)

    Mulgund, Sandeep S.; Stengel, Robert F.

    1992-01-01

    Recovery performance of a commuter-type aircraft in a microburst encounter is studied using a constant-pitch-attitude strategy and flight path optimization. Results obtained indicate that the pitch attitude which maximized climb rate in a wind shear condition is strongly dependent on whether the aircraft is subjected to a horizontal shear or a downdraft. The pitch attitude which maximizes ground clearance depends on the altitude of the encounter, the strength of the microburst, and the initial position of the aircraft with respect to the downburst core. Best results are obtained at relatively low target pitch angles, in severe wind shear encounters at very low altitudes. A technique for maximizing ground clearance involves maintaining a low pitch attitude early in the encounter, followed by a gradual pitch-up that ceases when the wind shear has been excited.

  11. Neural Basis of Stimulus-Angle-Dependent Motor Control of Wind-Elicited Walking Behavior in the Cricket Gryllus bimaculatus

    PubMed Central

    Oe, Momoko; Ogawa, Hiroto

    2013-01-01

    Crickets exhibit oriented walking behavior in response to air-current stimuli. Because crickets move in the opposite direction from the stimulus source, this behavior is considered to represent ‘escape behavior’ from an approaching predator. However, details of the stimulus-angle-dependent control of locomotion during the immediate phase, and the neural basis underlying the directional motor control of this behavior remain unclear. In this study, we used a spherical-treadmill system to measure locomotory parameters including trajectory, turn angle and velocity during the immediate phase of responses to air-puff stimuli applied from various angles. Both walking direction and turn angle were correlated with stimulus angle, but their relationships followed different rules. A shorter stimulus also induced directionally-controlled walking, but reduced the yaw rotation in stimulus-angle-dependent turning. These results suggest that neural control of the turn angle requires different sensory information than that required for oriented walking. Hemi-severance of the ventral nerve cords containing descending axons from the cephalic to the prothoracic ganglion abolished stimulus-angle-dependent control, indicating that this control required descending signals from the brain. Furthermore, we selectively ablated identified ascending giant interneurons (GIs) in vivo to examine their functional roles in wind-elicited walking. Ablation of GI8-1 diminished control of the turn angle and decreased walking distance in the initial response. Meanwhile, GI9-1b ablation had no discernible effect on stimulus-angle-dependent control or walking distance, but delayed the reaction time. These results suggest that the ascending signals conveyed by GI8-1 are required for turn-angle control and maintenance of walking behavior, and that GI9-1b is responsible for rapid initiation of walking. It is possible that individual types of GIs separately supply the sensory signals required to control wind-elicited walking. PMID:24244644

  12. Neural basis of stimulus-angle-dependent motor control of wind-elicited walking behavior in the cricket Gryllus bimaculatus.

    PubMed

    Oe, Momoko; Ogawa, Hiroto

    2013-01-01

    Crickets exhibit oriented walking behavior in response to air-current stimuli. Because crickets move in the opposite direction from the stimulus source, this behavior is considered to represent 'escape behavior' from an approaching predator. However, details of the stimulus-angle-dependent control of locomotion during the immediate phase, and the neural basis underlying the directional motor control of this behavior remain unclear. In this study, we used a spherical-treadmill system to measure locomotory parameters including trajectory, turn angle and velocity during the immediate phase of responses to air-puff stimuli applied from various angles. Both walking direction and turn angle were correlated with stimulus angle, but their relationships followed different rules. A shorter stimulus also induced directionally-controlled walking, but reduced the yaw rotation in stimulus-angle-dependent turning. These results suggest that neural control of the turn angle requires different sensory information than that required for oriented walking. Hemi-severance of the ventral nerve cords containing descending axons from the cephalic to the prothoracic ganglion abolished stimulus-angle-dependent control, indicating that this control required descending signals from the brain. Furthermore, we selectively ablated identified ascending giant interneurons (GIs) in vivo to examine their functional roles in wind-elicited walking. Ablation of GI8-1 diminished control of the turn angle and decreased walking distance in the initial response. Meanwhile, GI9-1b ablation had no discernible effect on stimulus-angle-dependent control or walking distance, but delayed the reaction time. These results suggest that the ascending signals conveyed by GI8-1 are required for turn-angle control and maintenance of walking behavior, and that GI9-1b is responsible for rapid initiation of walking. It is possible that individual types of GIs separately supply the sensory signals required to control wind-elicited walking. PMID:24244644

  13. Limited angle C-arm tomosynthesis reconstruction algorithms

    NASA Astrophysics Data System (ADS)

    Malalla, Nuhad A. Y.; Xu, Shiyu; Chen, Ying

    2015-03-01

    In this paper, C-arm tomosynthesis with digital detector was investigated as a novel three dimensional (3D) imaging technique. Digital tomosythses is an imaging technique to provide 3D information of the object by reconstructing slices passing through the object, based on a series of angular projection views with respect to the object. C-arm tomosynthesis provides two dimensional (2D) X-ray projection images with rotation (-/+20 angular range) of both X-ray source and detector. In this paper, four representative reconstruction algorithms including point by point back projection (BP), filtered back projection (FBP), simultaneous algebraic reconstruction technique (SART) and maximum likelihood expectation maximization (MLEM) were investigated. Dataset of 25 projection views of 3D spherical object that located at center of C-arm imaging space was simulated from 25 angular locations over a total view angle of 40 degrees. With reconstructed images, 3D mesh plot and 2D line profile of normalized pixel intensities on focus reconstruction plane crossing the center of the object were studied with each reconstruction algorithm. Results demonstrated the capability to generate 3D information from limited angle C-arm tomosynthesis. Since C-arm tomosynthesis is relatively compact, portable and can avoid moving patients, it has been investigated for different clinical applications ranging from tumor surgery to interventional radiology. It is very important to evaluate C-arm tomosynthesis for valuable applications.

  14. Radio occultation bending angle anomalies during tropical cyclones

    NASA Astrophysics Data System (ADS)

    Biondi, R.; Neubert, T.; Syndergaard, S.; Nielsen, J. K.

    2011-06-01

    The tropical deep convection affects the radiation balance of the atmosphere changing the water vapor mixing ratio and the temperature of the upper troposphere lower stratosphere. The aim of this work is to better understand these processes and to investigate if severe storms leave a significant signature in radio occultation profiles in the tropical tropopause layer. Using tropical cyclone best track database and data from different GPS radio occultation missions (COSMIC, GRACE, CHAMP, SACC and GPSMET), we selected 1194 profiles in a time window of 3 h and a space window of 300 km from the eye of the cyclone. We show that the bending angle anomaly of a GPS radio occultation signal is typically larger than the climatology in the upper troposphere and lower stratosphere and that a double tropopause during deep convection can easily be detected using this technique. Comparisons with co-located radiosondes, climatology of tropopause altitudes and GOES analyses are also shown to support the hypothesis that the bending angle anomaly can be used as an indicator of convective towers. The results are discussed in connection to the GPS radio occultation receiver which will be part of the Atomic Clock Ensemble in Space (ACES) payload on the International Space Station.

  15. Radio occultation bending angle anomalies during tropical cyclones

    NASA Astrophysics Data System (ADS)

    Biondi, R.; Neubert, T.; Syndergaard, S.; Nielsen, J.

    2011-02-01

    The tropical deep convection affects the radiation balance of the atmosphere changing the water vapor mixing ratio and the temperature of the upper troposphere lower stratosphere. The aim of this work is to better understand these processes and to investigate if severe storms leave a significant signature in radio occultation profiles in the tropical tropopause layer. Using tropical cyclone best track database and data from different GPS radio occultation missions (COSMIC, GRACE, CHAMP, SACC and GPSMET), we selected 1194 profiles in a time window of 3 h and a space window of 300 km from the eye of the cyclone. We show that the bending angle anomaly of a GPS radio occultation signal is typically larger than the climatology in the upper troposphere and lower stratosphere and that a double tropopause during deep convection can easily be detected using this technique. Comparisons with co-located radiosondes, climatology of tropopause altitudes and GOES analyses are also shown to support the hypothesis that the bending angle anomaly can be used as an indicator of convective towers. The results are discussed in connection to the GPS radio occultation receiver which will be part of the Atomic Clock Ensemble in Space (ACES) payload on the International Space Station.

  16. A high performance angle-resolving electron spectrometer

    NASA Astrophysics Data System (ADS)

    Rossnagel, K.; Kipp, L.; Skibowski, M.; Harm, S.

    2001-07-01

    We report on our new versatile photoelectron spectrometer Angular Spectrometer for Photoelectrons with High Energy REsolution (ASPHERE) which is part of beamline W3.2 (photon energies from 5 to 40 eV) but also compatible with beamline BW3 (40-1500 eV) at the Hamburger Synchrotronstrahlungslabor (HASYLAB). ASPHERE is a 180° spherical analyzer ( r0=100 mm) with a four-element input lens and is mounted on a two-axes goniometer with computer-controlled stepper motors which enables sequential angle-scanned measurements. The input lens is equipped with an iris aperture so that the angular resolution can be continuously adjusted from 0.2° to 5°. The fringe field of the condenser has been corrected for by tilting the angle of the input lens against the base plane of the hemispheres resulting in an overall energy resolution of 10 meV. To improve the speed of data acquisition three standard channeltron detectors are installed in the image plane of the analyzer which will be replaced by a multidetection system in the near future.

  17. Stresses and deformations in angle-ply composite tubes

    NASA Technical Reports Server (NTRS)

    Rousseau, Carl Q.; Hyer, Michael W.; Tompkins, Stephen S.

    1987-01-01

    The stress and deformations in angle-ply composite tubes subjected to axisymmetric thermal loading were investigated both experimentally and analytically. For the theoretical portion a generalized plane strain elasticity analysis was developed. The analysis included mechanical and thermal loading, and temperature-dependent material properties. The elasticity analysis was also used to study the effect of including a thin metallic coating on a graphite-epoxy tube. The stresses in the coatings were found to be quite high, exceeding the yield stress of aluminum. An important finding in the analytical studies was the fact that even tubes with a balanced-symmetric lamination sequence exhibit shear deformation, or twist. For the experimental portion an apparatus was developed to measure torsional and axial response in the temperature range of 140 to 360 K. Eighteen specimens were tested, combining three material systems, eight lamination sequences, and three off-axis ply orientation angles. For the twist response, agreement between analysis and experiment was found to be good. The axial response of the tubes tested was found to be greater than predicted by a factor of three. As a result, it is recommended that the thermally induced axial deformations be investigated, both experimentally and analytically.

  18. Wide acceptance angle, high concentration ratio, optical collector

    NASA Technical Reports Server (NTRS)

    Kruer, Mark Arthur (inventor)

    1990-01-01

    The invention is directed to an optical collector requiring a wide acceptance angle, and a high concentration ratio. The invention is particularly adapted for use in solar collectors of cassegrain design. The optical collector system includes a parabolic circular concave primary mirror and a hyperbolic circular convex secondary mirror. The primary mirror includes a circular hole located at its center wherein a solar collector is located. The mirrored surface of the secondary mirror has three distinct zones: a center circle, an on-axis annulus, and an off-axis section. The parabolic shape of the primary mirror is chosen so that the primary mirror reflects light entering the system on-axis onto the on-axis annulus. A substantial amount of light entering the system off-axis is reflected by the primary mirror onto either the off-axis section or onto the center circle. Subsequently, the off-axis sections reflect the off-axis light toward the solar collector. Thus, off-axis light is captured which would otherwise be lost to the system. The novelty of the system appears to lie in the configuration of the primary mirror which focuses off-axis light onto an annular portion of the secondary mirror to enable capture thereof. This feature results in wide acceptance angle and a high concentration ratio, and also compensates for the effects of non-specular reflection, and enables a cassegrain configuration to be used where such characteristics are required.

  19. Wide Angle Polarization Analysis with Neutron Spin Filters

    NASA Astrophysics Data System (ADS)

    Ye, Q.; Gentile, T. R.; Anderson, J.; Broholm, C.; Chen, W. C.; DeLand, Z.; Erwin, R. W.; Fu, C. B.; Fuller, J.; Kirchhoff, A.; Rodriguez-Rivera, J. A.; Thampy, V.; Walker, T. G.; Watson, S.

    We report substantial improvements in a compact wide angle neutron spin filter system that was recently employed on the Multi- Axis Crystal Spectrometer at the Center for Neutron Research at the U.S. National Institute of Standards and Technology. The apparatus consists of a cylindrical 3He polarizer cell and wide-angle 3He analyzer cells, a vertical solenoid to provide a uniform magnetic field, and a shielded radio-frequency solenoid for the polarizer cell. Nuclear magnetic resonance is employed to reverse the polarization in the polarizer cell and monitor the 3He polarization in all cells. The first experiment using this apparatus was carried out with cylindrical analyzer cells with limited angular coverage due to low polarizations in fused quartz cells. We present results for aluminosilicate glass analyzer cells that cover 110 ? and have long relaxation times (100 h to 400 h). Using two 100 W diode bars spectrally narrowed with chirped volume Bragg gratings, we have obtained 65% - 80% 3He polarization in these cells. The 3He polarization has been measured by neutron transmission and electron paramagnetic resonance. Additional progress includes an improved holding field solenoid and decreased spin-flip losses.

  20. Position angles and coplanarity of multiple systems from transit timing

    NASA Astrophysics Data System (ADS)

    Ofir, Aviv

    2014-01-01

    Aims: We compare the apparent difference in timing of transiting planets (or eclipsing binaries) that are observed from widely separated locations (parallactic delay). Methods: A simple geometrical argument allows us to show that the apparent timing difference also depends on the sky position angle of the planetary (or secondary) orbit, relative to the ecliptic plane. Results: Our calculation of the magnitude of the effect for all currently known planets (should they exhibit transits) find that almost 200 of them - mostly radial-velocity detected planets - have predicted timing effects greater than 1 s. We also compute the theoretical timing precision for the PLATO mission, which will observe a similar stellar population and find that a 1 s effect will frequently be easily observable. We also find that the sky coplanarity of multiple objects in the same system can be probed more easily than the sky position angle of each of the objects separately. Conclusions: We show that a new observable from transit photometry becomes available when very high-precision transit timing is available. We find that there is a good match between projected capabilities of the future space missions PLATO and CHEOPS and the new observable. We specify some initial science questions that this new observable may be able to address.