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1

Sensitivity of MODIS 2.1 micron Channel for Off-Nadir View Angles for Use in Remote Sensing of Aerosol  

NASA Technical Reports Server (NTRS)

Remote sensing of aerosol over land, from MODIS will be based on dark targets using mid-IR channels 2.1 and 3.9 micron. This approach was developed by Kaufman et al (1997), who suggested that dark surface reflectance in the red (0.66 micron -- rho(sub 0.66)) channel is half of that at 2.2 micron (rho(sub 2.2)), and the reflectance in the blue (0.49 micron - rho(sub 0.49)) channel is a quarter of that at 2.2 micron. Using this relationship, the surface reflectance in the visible channels can be predicted within Delta.rho(sub 0.49) approximately Delat.rho(sub 0.66) approximately 0.006 from rho(sub 2.2) for rho(sub 2.2) <= 0.10. This was half the error obtained using the 3.75 micron and corresponds to an error in aerosol optical thickness of Delat.tau approximately 0.06. These results, though applicable to several biomes (e.g. forests, and brighter lower canopies), have only been tested at one view angle - the nadir (theta = 0 deg). Considering the importance of the results in remote sensing of aerosols over land surfaces from space, we are validating the relationships for off-nadir view angles using Cloud Absorption Radiometer (CAR) data. The CAR data are available for channels between 0.3 and 2.3 micron and for different surface types and conditions: forest, tundra, ocean, sea-ice, swamp, grassland and over areas covered with smoke. In this study we analyzed data collected during the Smoke, Clouds, and Radiation - Brazil (SCAR-B) experiment to validate Kaufman et al.'s (1997) results for non-nadir view angles. We will show the correlation between rho(sub 0.472), rho(sub 0.675), and rho(sub 2.2) for view angles between nadir (0 deg) and 55 deg off-nadir, and for different viewing directions in the backscatter and forward scatter directions.

Gatebe, C. K.; King, M. D.; Tsay, S.-C.; Ji, Q.

2000-01-01

2

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  

NASA Technical Reports Server (NTRS)

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 altitude of 705 km on July 15, 2004 from Vandenberg Air Force Base, California. Nadir spectra are recorded at 0.06/cm spectral resolution with a nadir footprint of 5 x 8 km. We describe the TES retrieval approach for the analysis of the nadir measurements, report averaging kernels for typical tropical and polar ocean locations, characterize random and systematic errors for those locations, and describe instrument performance changes in the CO spectral region as a function of time. Sample maps of retrieved CO for the middle and upper troposphere from global surveys during December 2005 and April 2006 highlight the potential of the results for measurement and tracking of global pollution and determining air quality from space.

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

2006-01-01

3

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)

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.

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

2014-09-01

4

First results from a rotational Raman scattering cloud algorithm applied to the Suomi National Polar-orbiting Partnership (NPP) Ozone Mapping Profiler Spectrometer (OMPS) nadir mapper  

NASA Astrophysics Data System (ADS)

This paper reports initial results from an Ozone Mapping 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 ultra-violet 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 the MODIS imaging radiometer. 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 appears to improve OMPS total column ozone estimates slightly.

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

2014-03-01

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

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

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

6

Nadir PSA level and time to nadir PSA are prognostic factors in patients with metastatic prostate cancer  

PubMed Central

Background Primary androgen deprivation therapy (PADT) is the most effective systemic therapy for patients with metastatic prostate cancer. Nevertheless, once PSA progression develops, the prognosis is serious and mortal. We sought to identify factors that predicted the prognosis in a series of patients with metastatic prostate cancer. Methods Two-hundred eighty-six metastatic prostate cancer patients who received PADT from 1998 to 2005 in Nara Uro-Oncology Research Group were enrolled. The log-rank test and Cox’s proportional hazards model were used to determine the predictive factors for prognosis; rate of castration-resistant prostate cancer (CRPC) and overall survival. Results The median age, follow-up period and PSA level at diagnosis were 73 years, 47 months and 174 ng/mL, respectively. The 5-year overall survival rate was 63.0%. The multivariable analysis showed that Gleason score (Hazard ratio [HR]:1.362; 95% confidence interval [C.I.], 1.023-1.813), nadir PSA (HR:6.332; 95% C.I., 4.006-9.861) and time from PADT to nadir (HR:4.408; 95% C.I., 3.099-6.271) were independent prognostic factors of the incidence of CRPC. The independent parameters in the multivariate analysis that predicted overall survival were nadir PSA (HR:5.221; 95% C.I., 2.757-9.889) and time from PADT to nadir (HR:4.008; 95% C.I., 2.137-7.517). Conclusions Nadir PSA and time from PADT to nadir were factors that affect both CRPC and overall survival in a cohort of patients with metastatic prostate cancer. Lower nadir PSA level and longer time from PADT to nadir were good for survival and progression. PMID:24773608

2014-01-01

7

Angles.  

National Technical Information Service (NTIS)

Shows the Brownstone Kids teaching others how to dance. Illustrates angles as they turn and sing 'Get the Angles.' The group goes to a community center for playing pool in 'Calling Shoots.' Discusses angles showing the 90-degree, 45-degree, and 180-degree...

1994-01-01

8

Angles  

NSDL National Science Digital Library

This interactive Flash applet enables students, using estimation and measurement skills, to investigate angles. Teachers can use this page for demonstrating how to read a protractor, and the protractor can be hidden to give students practice in estimating angle measures. The size of the angle can be controlled or chosen randomly.

Bunker, Dan

2011-01-01

9

Correction of Sampling Errors in Ocean Surface Cross-Sectional Estimates from Nadir-Looking Weather Radar  

NASA Technical Reports Server (NTRS)

The return from the ocean surface has a number of uses for airborne meteorological radar. The normalized surface cross section has been used for radar system calibration, estimation of surface winds, and in algorithms for estimating the path-integrated attenuation in rain. However, meteorological radars are normally optimized for observation of distributed targets that fill the resolution volume, and so a point target such as the surface can be poorly sampled, particularly at near-nadir look angles. Sampling the nadir surface return at an insufficient rate results in a negative bias of the estimated cross section. This error is found to be as large as 4 dB using observations from a high-altitude airborne radar. An algorithm for mitigating the error is developed that is based upon the shape of the surface echo and uses the returned signal at the three range gates nearest the peak surface echo.

Caylor, I. Jeff; Meneghini, R.; Miller, L. S.; Heymsfield, G. M.

1997-01-01

10

Angles  

NSDL National Science Digital Library

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

Foundation, Shodor E.

2004-01-01

11

Angles  

NSDL National Science Digital Library

This lesson is designed to introduce students to different types of angles including acute, obtuse, and right. The lesson also introduces ways to compare angles such as alternate interior, corresponding, and many others. This lesson provides links to discussions and activities related to angles as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2010-01-01

12

Review of weak mixing angle results at SLC and LEP  

SciTech Connect

In this paper, the authors review recent precise measurements of the weak mixing angle by the SLD experiment at SLC and by the ALEPH, DELPHI, L3, and OPAL experiments at LEP. If they assume that the Minimal Standard Model provides a complete description of the quark and lepton couplings to the Z boson, they find sin{sup 2} {theta}{sub W}{sup eff} = 0.23143 {+-} 0.00028. If this assumption is relaxed to apply to lepton couplings only, they find sin{sup 2}{theta}{sub W}{sup eff} = 0.23106 {+-} 0.00035. They compare these results with other precision electroweak tests.

Woods, M.

1995-10-01

13

S-NPP OMPS Nadir Performance and Calibration  

NASA Astrophysics Data System (ADS)

This presentation analyzes the in-flight performance of the S-NPP OMPS Nadir instruments and evaluates sensors' on-orbit calibrations. During the past two year, OMPS has collected all types of orbital calibration and science data that have allowed us to better understand the two Nadir sensors' on-orbit performances, and consequently to establish the baseline calibrations during the early orbital checkout and intensive calibration and validation of the instruments. This presentation evaluates the orbital sensors' performances and verifies the orbital calibration. From studies that we have conducted so far since the sensor launch,the largest term in the sensor calibration uncertainty is the wavelength shift effect of 0.15 nm when the sensor transitioned from ground to orbit. Our results have also demonstrated that sensor on-orbit performance complies with the system specifications, while the final adjustments of stray-light correction are still being made to optimize OMPS Sensor Data Records (SDRs).

Pan, Sherry; Wu, Fred

2014-05-01

14

Angled Injection: Turbulent Flow Hybrid Bearings Comparison to Test Results  

NASA Technical Reports Server (NTRS)

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.

SanAndres, Luis; Childs, Dara

1997-01-01

15

NADIR: A Flexible Archiving System Current Development  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

16

Impact of Footprint Diameter and Off-Nadir Pointing on the Precision of Canopy Height Estimates from Spaceborne Lidar  

NASA Technical Reports Server (NTRS)

A spaceborne lidar mission could serve multiple scientific purposes including remote sensing of ecosystem structure, carbon storage, terrestrial topography and ice sheet monitoring. The measurement requirements of these different goals will require compromises in sensor design. Footprint diameters that would be larger than optimal for vegetation studies have been proposed. Some spaceborne lidar mission designs include the possibility that a lidar sensor would share a platform with another sensor, which might require off-nadir pointing at angles of up to 16 . To resolve multiple mission goals and sensor requirements, detailed knowledge of the sensitivity of sensor performance to these aspects of mission design is required. This research used a radiative transfer model to investigate the sensitivity of forest height estimates to footprint diameter, off-nadir pointing and their interaction over a range of forest canopy properties. An individual-based forest model was used to simulate stands of mixed conifer forest in the Tahoe National Forest (Northern California, USA) and stands of deciduous forests in the Bartlett Experimental Forest (New Hampshire, USA). Waveforms were simulated for stands generated by a forest succession model using footprint diameters of 20 m to 70 m. Off-nadir angles of 0 to 16 were considered for a 25 m diameter footprint diameter. Footprint diameters in the range of 25 m to 30 m were optimal for estimates of maximum forest height (R(sup 2) of 0.95 and RMSE of 3 m). As expected, the contribution of vegetation height to the vertical extent of the waveform decreased with larger footprints, while the contribution of terrain slope increased. Precision of estimates decreased with an increasing off-nadir pointing angle, but off-nadir pointing had less impact on height estimates in deciduous forests than in coniferous forests. When pointing off-nadir, the decrease in precision was dependent on local incidence angle (the angle between the off-nadir beam and a line normal to the terrain surface) which is dependent on the off-nadir pointing angle, terrain slope, and the difference between the laser pointing azimuth and terrain aspect; the effect was larger when the sensor was aligned with the terrain azimuth but when aspect and azimuth are opposed, there was virtually no effect on R2 or RMSE. A second effect of off-nadir pointing is that the laser beam will intersect individual crowns and the canopy as a whole from a different angle which had a distinct effect on the precision of lidar estimates of height, decreasing R2 and increasing RMSE, although the effect was most pronounced for coniferous crowns.

Pang, Yong; Lefskky, Michael; Sun, Guoqing; Ranson, Jon

2011-01-01

17

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

NASA Technical Reports Server (NTRS)

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).

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

1990-01-01

18

Latest Results of 3D Topographic Mapping Using Lunar Reconnaissance Orbiter Narrow-Angle Camera Data  

NASA Astrophysics Data System (ADS)

This abstract presents the latest research results and quantitative analysis of topographic mapping using Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Cameras (NAC) conducted at the Ohio State University.

Li, R.; Wang, W.; He, S.; Yan, L.; Meng, X.; Crawford, J.; Robinson, M. S.; Tran, T.; Archinal, B. A.; Lroc Team

2011-03-01

19

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

20

the angled package to the present horizontal sur-face as result of erosion.  

E-print Network

the angled package to the present horizontal sur- face as result of erosion. Despite the age uncertainties of the polar deposits, the strength of CO2 ice is insufficient to support the long-term topography and is in charge of in-flight instrument commissioning and of the SHARAD Operations Center. The Mars Reconnaissance

Zuber, Maria

21

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

PubMed Central

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

2014-01-01

22

[Results of pikamilon use in the treatment of patients with open-angle glaucoma].  

PubMed

Administration of pikamilon, a cerebrovascular and nootropic drug, to patients with primary open-angle glaucoma with normalized intraocular pressure and declining visual function resulted in improvement of the central and peripheral visual fields manifesting by improvement of individual sensitivity threshold, decreased area and intensity of scotomas; the treatment had a favorable effect on light sensitivity and vision acuity in some patients. No noticeable effect on arterial pressure was observed. The drug did not reduce the intraocular pressure. PMID:7871655

Kolomo?tseva, E M; Ermakova, V N; Abdulkadyrova, M Zh

1994-01-01

23

Piecewise linear car-following modeling Nadir Farhi  

E-print Network

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

Boyer, Edmond

24

PLANT ANIMAL INTERACTIONS Nadir Erbilgin Paal Krokene Erik Christiansen  

E-print Network

and inducible defense mechanisms against bark beetle colonization (reviewed by Franceschi et al. 2005PLANT ANIMAL INTERACTIONS Nadir Erbilgin Ã? Paal Krokene Ã? Erik Christiansen Gazmend Zeneli Ã? Jonathan Gershenzon Exogenous application of methyl jasmonate elicits defenses in Norway spruce (Picea

Erbilgin, Nadir

25

Nadir looking airborne radar and possible applications to forestry  

Microsoft Academic Search

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.

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

1987-01-01

26

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

SciTech Connect

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.

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

1990-01-01

27

First-Day Newborn Weight Loss Predicts In-Hospital Weight Nadir for Breastfeeding Infants  

PubMed Central

Abstract Background Exclusive breastfeeding reduces infant infectious disease. Losing ?10% birth weight may lead to formula use. The predictive value of first-day weight loss for subsequent weight loss has not been studied. The objective of the present study was to evaluate the relationship between weight loss at <24 hours and subsequent in-hospital weight loss ?10%. Methods For 1,049 infants, we extracted gestational age, gender, delivery method, feeding type, and weights from medical records. Weight nadir was defined as the lowest weight recorded during birth hospitalization. We used multivariate logistic regression to assess the effect of first-day weight loss on subsequent in-hospital weight loss. Results Mean in-hospital weight nadir was 6.0?±?2.6%, and mean age at in-hospital weight nadir was 38.7?±?18.5 hours. While in the hospital 6.4% of infants lost ?10% of birth weight. Infants losing ?4.5% birth weight at <24 hours had greater risk of eventual in-hospital weight loss ?10% (adjusted odds ratio 3.57 [1.75, 7.28]). In this cohort, 798 (76.1%) infants did not have documented weight gain while in the hospital. Conclusions Early weight loss predicts higher risk of ?10% in-hospital weight loss. Infants with high first-day weight loss could be targeted for further research into improved interventions to promote breastfeeding. PMID:20113202

Bokser, Seth; Newman, Thomas B.

2010-01-01

28

Tropospheric ozone retrieval by using SCIAMACHY Limb-Nadir-Matching method  

NASA Astrophysics Data System (ADS)

Tropospheric ozone is photochemically produced during pollution events and transported from the stratosphere towards the troposphere. It is the third most important green house gases and the main component of summer smog. Global covered satellite measurements are well suitable to investigate sources, sinks, and transport mechanisms of tropospheric ozone in a global view, and to study a characteristic behaviour of the tropospheric ozone in regions. However, the usage of satellite data is associated to a large uncertainty as 90% ozone is located in the stratosphere and only the remaining part of 10% can be observed in the troposphere. The limb-nadir matching (LNM) technique is one of the methods suitable to retrieve tropospheric ozone distributions from space borne observations of the scattered solar light in the UV-visible spectral range. In this study we apply the LNM approach to alternating limb and nadir measurements performed by the SCIAMACHY instrument. A precise tropopause height is used to subtract the stratospheric ozone from the total ozone amount for each matching point. The focus of this work is to reduce the uncertainty of the resulting tropospheric ozone distributions by analysing possible error sources, refining both limb and nadir retrievals and the matching technique.

Jia, Jia; Ladstätter-Weissenmayer, Annette; Ebojie, Felix; Rozanov, Alexei; Burrows, John

2014-05-01

29

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

SciTech Connect

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.

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

30

Method for evaluating bow tie filter angle-dependent attenuation in CT: Theory and simulation results  

PubMed Central

Purpose: Dosimetry in computed tomography (CT) is increasingly based on Monte Carlo studies that define the dose in the patient (in mGy) as a function of air kerma (free in air) at isocenter (mGy). The accuracy of Monte Carlo studies depends in part on the accuracy of the characterization of the bow tie filter for a given CT scanner model. A simple method for characterizing the bow tie filter attenuation profile in CT scanners would therefore be very useful. The theory behind such a method is proposed. Methods: A measurement protocol is discussed mathematically and demonstrated using computer simulation. The proposed method requires the placement of a radiation monitor at the periphery of the CT field, and the time domain signal (kerma rate versus time) is measured with good temporal resolution (?200 Hz or better) and with all other objects (e.g., patient couch) retracted from the field of view. Knowledge of the source to isocenter distance (or alternately, the isocenter to probe distance) is required. The stationary detector records the kerma rate versus time signal as the gantry rotates through several revolutions. From this temporal data, signal processing techniques are used to extract in-phase peaks, as well as out-of-phase kerma rate levels. From these data, the distance from isocenter to the probe can be determined (or, alternatively, the source to isocenter distance), and the angle-dependent bow tie filter attenuation can be computed. By measuring the angle-dependent bow tie filter attenuation at several kVp settings, the bow tie composition versus fan angle can be computed using basis decomposition techniques. Results: The simulations illustrated that with 2% added noise in the kerma rate versus time signal, the attenuation properties of a hypothetical two component (aluminum and polymethyl methacrylate) bow tie filter could be determined (r2>0.99). Although the computed basis material thicknesses were not exactly equal to the actual thicknesses, their combined attenuation factors matched that of the actual filter across kVp’s to within an average of 0.057%. Conclusions: It is concluded that the proposed method may provide a simple noninvasive approach to characterizing the performance of bow tie filters in CT systems; however, experimental validation is necessary. PMID:20175464

Boone, John M.

2010-01-01

31

Results of trench perpendicular wide angle seismic transects across the Manila subduction zone offshore southern Taiwan  

NASA Astrophysics Data System (ADS)

Multi-channel seismic reflection and wide-angle seismic data collected in 2009 aboard the R/V Marcus Langseth as part of the TAIGER program delineate the crustal structure of the Manila subduction zone in the northern South China Sea. As part of that project, we recorded marine seismic data using a deployment of ocean-bottom-seismometers (OBS) from the U.S. instrument pool and National Taiwan Ocean University. The region between northern Luzon and southern Taiwan evolves from oceanic subduction to incipient arc-continent collision. This presentation focuses on results of 2 offshore transects across the Manila subduction zone offshore southern Taiwan. Our goal here is to document the transition from pure oceanic subuction in the south to incipient arc-continent collision in the north, an understanding of which is integral for future geodynamic modeling of the advanced arc-continent collision in the north. The northern transect, line T2 is located at 21.4° N and used 30 OBSs. Line T1 was located at 20.5° N and used 27 OBSs across the Manila subduction zone. Data quality is extremely variable due to the local geology and quality of seafloor coupling at each instrument. Preliminary travel-time tomography of transect T2 shows a 10-15 km thick Eurasian crust with crustal velocities of 5-7.5 km/sec entering the Manila trench suggesting thinned continental crust, serpentinized upper mantle, or both in this region. The model shows the accretionary prism to be cored by high velocity material (6-7 km/sec) that may be the result of accretion of crustal material from the subducting Eurasian slab. We also observe asymmetric crustal thickening beneath the Gagua Ridge that is potentially a result of failed subduction of the Philippine Sea Plate westward along the Gagua Ridge. The wide-angle data is complimented by MCS reflection data to constrain sediment thickness, top of the crystalline basement, and moho. Preliminary work is in progress with transect T1 which will be presented along with transect T2 to provide an along strike comparison of the Manila subduction zone at both latitudes. We suspect that there may be more typical oceanic crust subducting in the south and primarily sedimentary material in the prism along transect T1.

Eakin, D. H.; McIntosh, K. D.; Van Avendonk, H. J.

2011-12-01

32

NADIR: Monitoring, Error Handling, and Logging with Tango  

NASA Astrophysics Data System (ADS)

The ingest and transport of a large amount of astronomical data, in geographically distributed archives, imply some challenging issues, like remote control and configuration, monitoring and logging anomalous conditions, fault tolerance and error handling. Based on this considerations and on our experience in data management, we started development of a New Archiving Distributed InfrastructuRe (NADIR), using Tango (Team 2013; S. Gara 2012), a well known distributed control system (DCSs) within scientific environments, taking advantage of its key features, like reliability, scalability, logging and alarm system, consolidated pattern and template, to solve this complexity. In this paper we discuss about design choices and technical aspects around this project.

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

2014-05-01

33

TEARES: Toroidal Energy- and Angle-Resolved Electron Spectrometer: Results and Progress to Date  

SciTech Connect

In order to keep up with the large improvements in synchrotron radiation, we have developed a toroidal-based electron spectrometer capable of collecting electrons emitted over a large angular range, whilst preserving emission direction information. This system has an analyser defined by spherical radius of 125 mm, cylindrical radius of 120 mm, sector angle of 142 deg., and usable azimuthal angle of {approx}230 deg. A 1 mm high analyser entrance slit provides a theoretical analyser resolution ({delta}E/PE) of 0.0081. The spectrometer has no blind spots and incorporates a working distance defined by a {approx}40 mm radius. It operates over the kinetic energy range <0.5 to 1000 eV and a pass energy range of {approx}0.5 to 25 eV. This system represents an enormous advance over other more typical spectrometers (e.g. hemispherical), as the solid acceptance angle is up to two orders of magnitude greater.

Siggel-King, M.R.F.; Quinn, F.M. [Daresbury Laboratory, Daresbury, Warrington, WA4 4AD (United Kingdom); Lindsay, R. [Daresbury Laboratory, Daresbury, Warrington, WA4 4AD (United Kingdom); Nanoscience Research Centre, University of Manchester, M13 9PL (United Kingdom); Department of Chemistry, University of Manchester, M13 9PL (United Kingdom); Pearson, J. F.; Fraser, G. W. [Department of Physics and Astronomy, University of Leicester, LE1 7RH (United Kingdom); Thornton, G. [Nanoscience Research Centre, University of Manchester, M13 9PL (United Kingdom); Department of Chemistry, University of Manchester, M13 9PL (United Kingdom)

2004-05-12

34

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

35

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

NASA Technical Reports Server (NTRS)

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.

Ahamad, Atiq; Moore, Richard K.

1993-01-01

36

Computerized data reduction techniques for nadir viewing remote sensors  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

37

Results of the first aircraft experiment with the wide-angle airborne laser ranging system  

Microsoft Academic Search

The first aircraft experiment with the wide-angle airborne laser ranging system has been conducted in May 1998 over a small network of 1 km2, equipped with 64 cube-corner retroreflectors. The ranging system was operated from a research aircraft (ARAT, Fokker 27) at an altitude of 1 km. Data have been collected during two 4-hour flights. The paper describes the data

O. Bock

2000-01-01

38

First aircraft experiment results with the wide-angle airborne laser ranging system  

Microsoft Academic Search

The first aircraft experiment with the Wide-Angle Airborne Laser Ranging System has been conducted in May 1998 over an air base in France equipped with a network of 64 cub-corner retroreflectors. The ranging system was operated from the Avion de Recherche Atmospherique et de Teledetection of CNES\\/IGN\\/INSU. Data have been collected during two 4-hour flights. The paper describes the data

Olivier Bock; Christian Thom; Michel Kasser

1999-01-01

39

TES/Aura L2 Formic Acid Nadir (TL2FORNS)  

TES/Aura L2 Formic Acid Nadir (TL2FORNS) News:  TES News Join TES ... 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 ...

2014-08-04

40

TES/Aura L2 Formic Acid Nadir (TL2FORN)  

TES/Aura L2 Formic Acid Nadir (TL2FORN) News:  TES News Join TES ... 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 ...

2014-08-04

41

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

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

2014-08-04

42

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

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

2014-08-04

43

Tropospheric Ozone Near-Nadir-Viewing IR Spectral Sensitivity and Ozone Measurements from NAST-I  

NASA Technical Reports Server (NTRS)

Infrared ozone spectra from near nadir observations have provided atmospheric ozone information from the sensor to the Earth's surface. Simulations of the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) from the NASA ER-2 aircraft (approximately 20 km altitude) with a spectral resolution of 0.25/cm were used for sensitivity analysis. The spectral sensitivity of ozone retrievals to uncertainties in atmospheric temperature and water vapor is assessed in order to understand the relationship between the IR emissions and the atmospheric state. In addition, ozone spectral radiance sensitivity to its ozone layer densities and radiance weighting functions reveals the limit of the ozone profile retrieval accuracy from NAST-I measurements. Statistical retrievals of ozone with temperature and moisture retrievals from NAST-I spectra have been investigated and the preliminary results from NAST-I field campaigns are presented.

Zhou, Daniel K.; Smith, William L.; Larar, Allen M.

2001-01-01

44

Pitch-angle scattering in magnetostatic turbulence. I. Test-particle simulations and the validity of analytical results  

E-print Network

Context. Spacecraft observations have motivated the need for a refined description of the phase-space distribution function. Of particular importance is the pitch-angle diffusion coefficient that occurs in the Fokker-Planck transport equation. Aims. Simulations and analytical test-particle theories are compared to verify the diffusion description of particle transport, which does not allow for non-Markovian behavior. Methods. A Monte-Carlo simulation code was used to trace the trajectories of test particles moving in turbulent magnetic fields. From the ensemble average, the pitch-angle Fokker-Planck coefficient is obtained via the mean square displacement. Results. It is shown that, while excellent agreement with analytical theories can be obtained for slab turbulence, considerable deviations are found for isotropic turbulence. In addition, all Fokker-Planck coefficients tend to zero for high time values.

Tautz, R C; Effenberger, F; Fichtner, H; Kopp, A

2013-01-01

45

Pitch-angle scattering in magnetostatic turbulence. I. Test-particle simulations and the validity of analytical results  

NASA Astrophysics Data System (ADS)

Context. Spacecraft observations have motivated the need for a refined description of the phase-space distribution function. Of particular importance is the pitch-angle diffusion coefficient that occurs in the Fokker-Planck transport equation. Aims: Simulations and analytical test-particle theories are compared to verify the diffusion description of particle transport, which does not allow for non-Markovian behavior. Methods: A Monte-Carlo simulation code was used to trace the trajectories of test particles moving in turbulent magnetic fields. From the ensemble average, the pitch-angle Fokker-Planck coefficient is obtained via the mean square displacement. Results: It is shown that, while excellent agreement with analytical theories can be obtained for slab turbulence, considerable deviations are found for isotropic turbulence. In addition, all Fokker-Planck coefficients tend to zero for high time values.

Tautz, R. C.; Dosch, A.; Effenberger, F.; Fichtner, H.; Kopp, A.

2013-10-01

46

Backscattering enhancement for Marshall-Palmer distributed rains for a W-band nadir-pointing radar with a finite beam width  

NASA Technical Reports Server (NTRS)

In this paper, we expand the previous theory to be applied to a generic drop size distribution with spheroidal raindrops including spherical raindrops. Results will be used to discuss the multiple scattering effects on the backscatter measurements acquired by a W-band nadir-pointing radar.

Kobayashi, Satoru; Tanelli, Simone; Im, Eastwood; Oguchi, Tomohiro

2005-01-01

47

Failure-plane angle in Bentheim sandstone subjected to true triaxial stresses: experimental results and theoretical prediction  

NASA Astrophysics Data System (ADS)

We conducted true triaxial tests in the high-porosity (n = 24%), quartz-rich (95%), Bentheim sandstone. An important objective was to investigate the dependence of failure-plane angle ? (angle between the normal to the plane and ?1 direction) on the prevailing stress conditions. We employed two distinct loading paths, and seven ?3 magnitudes (between 0 and 150 MPa). In tests using the common loading path, ?2 and ?3 were fixed, while ?1 was raised monotonically to failure. In tests using the novel loading path (which facilitate comparison with theoretical predictions), ?3 was fixed, and the Lode angle, ? (= tan-1 [(?1 - 2?2 + ?3) / 30.5(?1 - ?3)]) was kept constant by raising ?1 and ?2 simultaneously at a set ratio b [= (?2 -?3)/(?1 -?3)] until failure occurred. Six stress ratios b (= 0, 1/6, 1/3, 1/2, 3/4, 1), i.e. six ? (= tan-1 [(1-2b) / 30.5]) values from +?/6 (axisymmetric compression) to -?/6 (axisymmetric extension) were used. In axisymmetric common loading path tests, failure-plane angle ? generally declined as the applied ?3 = ?2 increased from about 80° at ?3 = ?2 = 0 MPa to 0° at ?3 = ?2 = 150 MPa (forming compaction bands). In tests where ?3 ? ?2, the resulting failure-plane strike was consistently parallel to ?2 direction. For low ?3, ? typically rose by up to 12° as ?2 rose from ?2 = ?3 to ?2 = ?1. However, the rise in ? with ?2 tended to diminish at higher ?3. A limiting case occurred at ?3 = 150 MPa, where failure plane remained at 0° , regardless of the rise in ?2. In the novel loading path tests, failure-plane angle ? declined monotonically for any given Lode angle ?, from roughly 80° to 0° , as the mean stress at failure (?oct,f) rose from about 20 MPa to around 220 MPa; for a constant ?oct,f, ? typically increased from 10° (at ?oct,f = 20 MPa) to 30° (at ?oct,f = 220 MPa) as ? dropped from +?/6 (?2 = ?3) to -?/6 (?2 = ?1). We compared the measured ? with that predicted using equation 28 in Rudnicki (2013), an extension of the Rudnicki and Rice (1975) prediction to include the third stress invariant ?. (Space does not permit detailing the equation in this abstract.) The theory treats octahedral shear stress at failure (?oct,f) and the resulting ? as dependent on ?oct,f and ?. We used two series of the novel loading path tests: axisymmetric compression (? = +?/6) and pure shear (? = 0) to constrain that dependence. The failure conditions in the novel loading path tests were then simulated to compare the predicted failure-plane angles with the experimental results. The predictions were in general agreement with the experimental data, except when ? = -?/6 (?2 = ?1). In the common loading path tests, failure prediction replicated the general rise of the experimentally observed ? with ?2 for a given ?3,as well as the diminished rise at high ?3 magnitudes. The reasonable agreement between the predicted and the observed failure-plane angle demonstrated the applicability and the limitations of Rudnicki's (2013) theory.

Ma, Xiaodong; Rudnicki, John; Haimson, Bezalel

2014-05-01

48

NADIR: A prototype system for detecting network and file system abuse  

SciTech Connect

This paper describes the design of a prototype computer misuse detection system for the Los Alamos Notional Laboratory's Integrated Computing Network (ICN). This automated expert system, the Network Anomaly Detection and Intrusion Reporter (NADIR), streamlines and supplements the manual audit record review traditionally performed by security auditors. NADIR compares network activity, as summarized in weekly profiles of individual users and the ICN as a whole, against expert rules that define security policy, improper or suspicious behavior, and normal user activity. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes analysis by NADIR of two types of ICN activity: user authentication and access control, and mass file storage. It highlights system design issues of data handling, exploiting existing auditing systems, and performing audit analysis at the network level.

Hochberg, J.G.; Jackson, K.A.; Stallings, C.A.; McClary, J.F.; DuBois, D.H.; Ford, J.R.

1992-01-01

49

NADIR: A prototype system for detecting network and file system abuse  

SciTech Connect

This paper describes the design of a prototype computer misuse detection system for the Los Alamos Notional Laboratory`s Integrated Computing Network (ICN). This automated expert system, the Network Anomaly Detection and Intrusion Reporter (NADIR), streamlines and supplements the manual audit record review traditionally performed by security auditors. NADIR compares network activity, as summarized in weekly profiles of individual users and the ICN as a whole, against expert rules that define security policy, improper or suspicious behavior, and normal user activity. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes analysis by NADIR of two types of ICN activity: user authentication and access control, and mass file storage. It highlights system design issues of data handling, exploiting existing auditing systems, and performing audit analysis at the network level.

Hochberg, J.G.; Jackson, K.A.; Stallings, C.A.; McClary, J.F.; DuBois, D.H.; Ford, J.R.

1992-10-01

50

Angle-resolved normal and resonant Auger transitions after photoabsorption - numerical results for HF  

NASA Astrophysics Data System (ADS)

A general theory is developed and numerical results are presented for the angular distribution of molecular Auger electrons emitted after photoabsorption. The angular distribution reflects the dynamical properties of both processes: the photoabsorption and the Auger emission. We will analyse in detail the difference between ionization and excitation by arbitrarily polarized photons. We will show that for resonant Auger transitions the primary photoexcitation can be treated analytically. Based on this result an expression for the asymmetry parameter 0953-4075/31/7/016/img7 is developed, which determines the Auger angular distribution. Numerical results for the parameter 0953-4075/31/7/016/img7 are presented for several resonant Auger transitions of HF.

Bonhoff, K.; Bonhoff, S.; Schimmelpfennig, B.; Nestmann, B.; Blum, K.

1998-04-01

51

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

E-print Network

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 $\\sim 100deg ^2$.

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

2001-03-05

52

Results of multiband (L, S, Ku band) propagation measurements and model for high elevation angle land mobile satellite channel  

NASA Technical Reports Server (NTRS)

Signal propagation in the land mobile satellite (LMS) service is an important consideration due to its critical impact on the overall economic and commercial viability of the system. At frequencies allocated for LMS systems, shadowing of the line-of-sight (LOS) signal as well as multipath propagation phenomena can severely impair the link availability. In particular, as most of the studies have shown, the shadowing of LOS signal causes long and deep fades in a variety of mobile environments due to the inherent nature of the channel between the satellite and a mobile. Roadside obstacles, such as buildings, trees, utility poles etc., in the immediate vicinity of a mobile and the surrounding terrain are major sources of signal shadowing in LMS links. Therefore, a proper knowledge of link degradation is essential for cost-effective planning of a satellite based mobile communication system. The results of a propagation campaign undertaken to characterize the fading nature of LMS channel at high elevation angles is presented. It was envisaged that one of the most important physical variables contributing to the amount of LOS signal shadowing is the elevation angle of the satellite. At higher elevation angles to the satellite, less obstructions in the direct satellite-to-mobile path would therefore amount to statistically better link availability. Narrowband channel measurements were carried out at three RF frequencies corresponding to L (1.3 GHz), S (2.32/2.45 GHz), and Ku (10.4 GHz) bands. The campaign itself was divided into two phases to observe the effects of seasonal variation of foliage on the roadside trees. Phase measurements were carried out in September 1991 and in April 1992. Some important aspects from the statistical analysis of the propagation data are presented.

Parks, M. A. N.; Butt, G.; Evans, Barry G.; Richharia, M.

1993-01-01

53

KaRIn on SWOT: modeling and simulation of near-nadir Ka-band interferometric SAR images  

NASA Astrophysics Data System (ADS)

The principal instrument of the wide-swath altimetry mission SWOT is KaRIn, a Ka-band interferometric SAR system operating on near-nadir swaths on both sides of the satellite track. Due to the short wavelength and particular observation geometry, there are very limited reports on the backscattering from natural surfaces. Simulators that cover both radiometric and geometric aspects are therefore developed in the framework of the CNES phase 0 and A studies of SWOT. This article presents the modeling and simulation approaches that have been adopted, and shows some preliminary simulation results.

Fjørtoft, Roger; Koudogbo, Fifamè; Duro, Javier; Ruiz, Christian; Gaudin, Jean-Marc; Mallet, Alain; Pourthie, Nadine; Lion, Christine; Ordoqui, Patrick; Arnaud, Alain

2010-10-01

54

Towards 3D Matching of Point Clouds Derived from Oblique and Nadir Airborne Imagery  

NASA Astrophysics Data System (ADS)

Because of the low-expense high-efficient image collection process and the rich 3D and texture information presented in the images, a combined use of 2D airborne nadir and oblique images to reconstruct 3D geometric scene has a promising market for future commercial usage like urban planning or first responders. The methodology introduced in this thesis provides a feasible way towards fully automated 3D city modeling from oblique and nadir airborne imagery. In this thesis, the difficulty of matching 2D images with large disparity is avoided by grouping the images first and applying the 3D registration afterward. The procedure starts with the extraction of point clouds using a modified version of the RIT 3D Extraction Workflow. Then the point clouds are refined by noise removal and surface smoothing processes. Since the point clouds extracted from different image groups use independent coordinate systems, there are translation, rotation and scale differences existing. To figure out these differences, 3D keypoints and their features are extracted. For each pair of point clouds, an initial alignment and a more accurate registration are applied in succession. The final transform matrix presents the parameters describing the translation, rotation and scale requirements. The methodology presented in the thesis has been shown to behave well for test data. The robustness of this method is discussed by adding artificial noise to the test data. For Pictometry oblique aerial imagery, the initial alignment provides a rough alignment result, which contains a larger offset compared to that of test data because of the low quality of the point clouds themselves, but it can be further refined through the final optimization. The accuracy of the final registration result is evaluated by comparing it to the result obtained from manual selection of matched points. Using the method introduced, point clouds extracted from different image groups could be combined with each other to build a more complete point cloud, or be used as a complement to existing point clouds extracted from other sources. This research will both improve the state of the art of 3D city modeling and inspire new ideas in related fields.

Zhang, Ming

55

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

E-print Network

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.

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

2005-10-01

56

Note on the Effect of Horizontal Gradients for Nadir-Viewing Microwave and Infrared Sounders  

NASA Technical Reports Server (NTRS)

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 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 cross track so that at the satellite swath edges, the satellite zenith angles can reach approx. 60 deg. The emission path through the atmosphere as observed by the satellite is therefore slanted with respect to the satellite footprint s zenith. Although radiative transfer codes currently in use at operational centers use the appropriate satellite zenith angle to compute brightness temperature, the input atmospheric fields are those from the vertical profile above the center of the satellite footprint. If horizontal gradients are present in the atmospheric fields, the use of a vertical atmospheric profile may produce an error. This note attempts to quantify the effects of horizontal gradients on AIRS and AMSU-A channels by computing brightness temperatures with accurate slanted atmospheric profiles. We use slanted temperature, water vapor, and ozone fields from data assimilation systems. We compare the calculated slanted and vertical brightness temperatures with AIRS and AMSU-A observations. We show that the effects of horizontal gradients on these sounders are generally small and below instrument noise. However, there are cases where the effects are greater than the instrument noise and may produce erroneous increments in an assimilation system. The majority of the affected channels have weighting functions that peak in the upper troposphere (water vapor sensitive channels) and above (temperature sensitive channels) and are unlikely t o significantly impact tropospheric numerical weather prediction. However, the errors could be significant for other applications such as stratospheric analysis. Gradients in ozone and tropospheric temperature appear to be well captured by the analyses. In contrast, gradients in upper stratospheric and mesospheric temperature as well as upper tropospheric humidity are less well captured. This is likely due in part to a lack of data to specify these fields accurately in the analyses. Advanced new sounders, like AIRS, may help to better specify these fields in the future.

Joiner, J.; Poli, P.

2004-01-01

57

Vertical information content of nadir measurements of tropospheric NO2 from satellite  

NASA Astrophysics Data System (ADS)

When applying satellite measurements in atmospheric pollution research, one commonly used species are tropospheric NO2 columns. They can be useful for the identification and evaluation of natural and anthropogenic NOx emissions and their changes over time as well as for process studies and for the investigation of atmospheric transport events. However, the lack of vertical resolution is one major limitation of the commonly used DOAS retrievals of NO2 columns from satellite observed radiances. Combined with the altitude-dependence of retrieval sensitivity, this entails the use of a priori information on the NO2 vertical profile. This significantly contributes to the retrieval uncertainties, which could be reduced if information on the vertical location of the NO2 could be retrieved from the measurements themselves. In this study, we investigate the vertical information content of nadir NO2 observations in the UV/visible wavelength range. For this purpose, we revisit the vertical sensitivity of DOAS retrievals of NO2, which is encoded in the averaging kernels, and contrast these findings with the results from a formal solution to the inverse radiative transfer problem, using synthetic spectra representing measurements over polluted regions. As a result, we can show that in certain cases, it is indeed possible to derive information on the vertical distribution of NO2 from the DOAS analysis alone, reducing the dependence of the retrievals on a priori information in these situations.

Hilboll, Andreas; Richter, Andreas; Burrows, John P.

2014-05-01

58

Prostate-Specific Antigen Nadir Within 12 Months of Prostate Cancer Radiotherapy Predicts Metastasis and Death  

PubMed Central

BACKGROUND The nadir prostate-specific antigen (PSA) at 1 year (nPSA12) was investigated as an early estimate of biochemical and clinical outcome after radiotherapy (RT) alone for localized prostate cancer. METHODS From May 1989 to November 1999, 1000 men received 3D conformal RT alone (median, 76 Gy) with minimum and median follow-up periods of 26 and 58 months, respectively, from the end of treatment. The calculation of PSA doubling time (PSADT) was possible in 657 patients. Multivariate analyses (MVAs) via Cox proportional hazards regression were used to determine the association of nPSA12 to biochemical failure (BF; ASTRO definition), distant metastasis (DM), cause-specific mortality (CSM), and overall mortality (OM). Dichotomization of nPSA12 was optimized by evaluating the sequential model likelihood ratio and P-values. RESULTS In MVA, nPSA12 as a continuous variable was independent of RT dose, T-stage, Gleason score, pretreatment initial PSA, age, and PSADT in predicting for BF, DM, CSM, and OM. Dichotomized nPSA12 (?2 versus >2 ng/mL) was independently related to DM and CSM. Kaplan-Meier 10-year DM rates for nPSA12 ?2 versus >2 ng/mL were 4% versus 19% (P < .0001). CONCLUSIONS nPSA12 is a strong independent predictor of outcome after RTalone for prostate cancer and should be useful in identifying patients at high risk for progression to metastasis and death. PMID:17133416

Alcantara, Pino; Hanlon, Alexandra; Buyyounouski, Mark K.; Horwitz, Eric M.; Pollack, Alan

2007-01-01

59

Complexities of nadir-looking radiometric temperature measurements of plant canopies  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

60

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

PubMed Central

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

2014-01-01

61

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

PubMed Central

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.

Tran, Ngan; Chapron, Bertrand

2006-01-01

62

Forced waves in the martian atmosphere from MGS TES nadir data  

Microsoft Academic Search

We have analyzed the temperature retrievals from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) nadir spectra to yield latitude-height resolved maps of various atmospheric forced wave modes as a function of season for a full Mars year. Among the isolated wave modes is the zonal mean, time mean temperature, which we used to derive zonal mean zonal winds and

D. Banfield; B. J. Conrath; M. D. Smith; P. R. Christensen; R. John Wilsond

2003-01-01

63

WP 11: Irradiance and nadir-and limb radiance The main activities in 2003  

E-print Network

WP 11: Irradiance and nadir- and limb radiance The main activities in 2003: 1. Validation of solar irradiance (WP 11.1) The solar irradiance was compared to that of other satellite data sources. These include: The solar irradiance is too high by about 8%, and is dependent on the actual spectral channel

Tilstra, Gijsbert

64

SO2 monitoring above Venus' clouds using VEx/SPICAV-UV nadir observations  

NASA Astrophysics Data System (ADS)

SO2 in the upper atmosphere of Venus is an important tracer of (i) its recent (within 10 million years) geological activity, (ii) the chemistry and photo-chemistry of sulfur-bearing species, including H2SO4-H2O underlying clouds and (iii) general circulation of the atmosphere bringing SO2-rich air up to levels where photo-chemical destruction occurs. The first monitoring, using Pioneer Venus and ground-based data, showed a two order-of-magnitude decrease from 1980 to 1995 [Esposito et al., 1988]. Latitudinal variations were also constrained in the early 1990s, and exhibited an increasing observable SO2 column density with increasing latitude [Zasova et al., 1993; Na et al., 1994]. Measurements of SO2 have resumed since 2006 mainly thanks to SPICAV/SOIR instrument on-board Venus Express, and first studies showed an opposite latitudinal gradient as well as relatively high SO2 abundance, comparable to the early 1980s [Belyaev et al., 2008; Marcq et al., 2011]. Here we show the results for the 2007-2010 epoch, using an improved version of Marcq et al.'s (2011) model able to cope with non-nadir observations. Strong variability is observed within short (daily) timescales , but there is evidence for two distinct regimes, the most frequent being identical to the situation in 2006 already published (rather high abundances, negative latitudinal gradient), but starting in late 2009, a new regime very similar to the situation during the early 1990s (low abundances, positive latitudinal gradients) has been observed, alternating with the common regime within a few Earth months. Simple modeling suggests that fluctuations in the general circulation and/or sporadic change in SO2 below 65 km may cause the alternation between both regimes. Bibliography: Esposito et al., JGR 93 (1988) Zasova et al., Icarus 105 (1993) Na et al., Icarus 112 (1994) Belyaev et al., JGR 113 (2008) Marcq et al., Icarus 211 (2011)

Marcq, E.; Montmessin, F.; Bertaux, J. L.; Belyaev, D.; Fedorova, A.

2012-04-01

65

Angle Sums  

NSDL National Science Digital Library

With this applet, students can examine the angles in a triangle, quadrilateral, pentagon, hexagon, heptagon or octagon. They can change the shape of the figure by dragging the vertices; the size of each angle is shown and the sum of the interior angles calculated. Students are challenged to find a relationship between the number of sides and the sum of the interior angles.

Illuminations, Nctm

2000-01-01

66

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)

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.

Kramer, Max

1932-01-01

67

Radiation physics and modelling for off-nadir satellite-sensing of non-Lambertian surfaces  

Microsoft Academic Search

The primary objective of this paper is to provide a deeper understanding of the physics of satellite remote-sensing when off-nadir observations are considered. Emphasis is placed on the analysis and modelling of atmospheric effects and the radiative transfer of non-Lambertian surface reflectance characteristics from ground-level to satellite locations. The authors evaluate the relative importance of spectral, spatial, angular, and temporal

S. A. W. Gerstl; C. Simmer

1986-01-01

68

Nadir Emissivity Radiative Transfer Models For Planetary Regolith: Current State of the Art  

Microsoft Academic Search

A decade ago, a paradigm for theoretically calculating the nadir emissivity values of planetary regolith laboratory proxy samples was established in the literature: determining single-scattering properties of the target light scattering particles via Mie theory and incorporating multiple-scattering via an analytical two-stream approximation to the radiative transfer (RT) equation. While a qualitative comparison between Mie\\/analytical RT hybrid model and lab

K. M. Pitman; M. J. Wolff; G. C. Clayton

2004-01-01

69

Validation of Tropospheric Emission Spectrometer (TES) nadir ozone profiles using ozonesonde measurements  

Microsoft Academic Search

We compare Tropospheric Emission Spectrometer (TES) version 2 (V002) nadir ozone profiles with ozonesonde profiles from the Intercontinental Chemical Transport Experiment Ozonesonde Network Study, the World Ozone and Ultraviolet Data Center, the Global Monitoring Division of the Earth System Research Laboratory, and the Southern Hemisphere Additional Ozonesonde archives. Approximately 1600 coincidences spanning 72.5°S–80.3°N from October 2004 to October 2006 are

Ray Nassar; Jennifer A. Logan; Helen M. Worden; Inna A. Megretskaia; Kevin W. Bowman; Gregory B. Osterman; Anne M. Thompson; David W. Tarasick; Shermane Austin; Hans Claude; Manvendra K. Dubey; Wayne K. Hocking; Bryan J. Johnson; Everette Joseph; John Merrill; Gary A. Morris; Mike Newchurch; Samuel J. Oltmans; Françoise Posny; F. J. Schmidlin; Holger Vömel; David N. Whiteman; Jacquelyn C. Witte

2008-01-01

70

Validation of Tropospheric Emission Spectrometer (TES) nadir ozone profiles using ozonesonde measurements  

Microsoft Academic Search

We compare Tropospheric Emission Spectrometer (TES) version 2 (V002) nadir ozone profiles with ozonesonde profiles from the Intercontinental Chemical Transport Experiment Ozonesonde Network Study, the World Ozone and Ultraviolet Data Center, the Global Monitoring Division of the Earth System Research Laboratory, and the Southern Hemisphere Additional Ozonesonde archives. Approximately 1600 coincidences spanning 72.5°S-80.3°N from October 2004 to October 2006 are

Ray Nassar; Jennifer A. Logan; Helen M. Worden; Inna A. Megretskaia; Kevin W. Bowman; Gregory B. Osterman; Anne M. Thompson; David W. Tarasick; Shermane Austin; Hans Claude; Manvendra K. Dubey; Wayne K. Hocking; Bryan J. Johnson; Everette Joseph; John Merrill; Gary A. Morris; Mike Newchurch; Samuel J. Oltmans; Françoise Posny; F. J. Schmidlin; Holger Vömel; David N. Whiteman; Jacquelyn C. Witte

2008-01-01

71

Radiation physics and modelling for off-nadir satellite-sensing of non-Lambertian surfaces  

NASA Technical Reports Server (NTRS)

The primary objective of this paper is to provide a deeper understanding of the physics of satellite remote-sensing when off-nadir observations are considered. Emphasis is placed on the analysis and modeling of atmospheric effects and the radiative transfer of non-Lambertian surface reflectance characteristics from ground-level to satellite locations. The relative importance of spectral, spatial, angular, and temporal reflectance characteristics for satellite-sensed identification of vegetation types in the visible and near-infrared wavelength regions is evaluated. The highest identification value is attributed to angular reflectance signatures. Using radiative transfer calculations to evaluate the atmospheric effects on angular reflectance distributions of vegetation surfaces, atmosphere-invariant angular reflectance features such as the 'hot spot' and the 'persistent valley' are identified. A new atmospheric correction formalism for complete angular reflectance distributions is described. A sample calculation demonstrates that a highly non-Lambertian measured surface reflectance distribution can be retrieved from simulated satellite data in the visible and near infrared to within about 20 percent accuracy for almost all view directions up to 60 deg off-nadir. Thus the high value of angular surface reflectance characteristics (the 'angular signature') for satellite-sensed feature identification is confirmed, which provides a scientific basis for future off-nadir satellite observations.

Gerstl, S. A.; Simmer, C.

1986-01-01

72

Effect of Nadir CD4+ T Cell Count on Clinical Measures of Periodontal Disease in HIV+ Adults before and during Immune Reconstitution on HAART  

PubMed Central

Background The contribution of HIV-infection to periodontal disease (PD) is poorly understood.  We proposed that immunological markers would be associated with improved clinical measures of PD. Methods We performed a longitudinal cohort study of HIV-infected adults who had started highly active antiretroviral therapy (HAART) <2 years. PD was characterized clinically as the percent of teeth with ?1 site with periodontal probing depth (PPD) ?5.0mm, recession (REC) >0mm, clinical attachment level (CAL) ?4.0mm, and bleeding on probing (BOP) at ?4 sites/tooth and microbiologically as specific periodontopathogen concentration. Linear mixed-effects models were used to assess the associations between immune function and PD. Results Forty (40) subjects with median 2.7 months on HAART and median nadir CD4+ T-cell count of 212 cells/?l completed a median 3 visits. Over 24 months, CD4+ T-cell count increased by a mean 173 cells/µl (p<0.001) and HIV RNA decreased by 0.5 log10 copies/ml (p<0.001); concurrently, PPD, CAL and BOP decreased by a mean 11.7%, 12.1%, and 14.7% respectively (all p<0.001). Lower nadir CD4+ T-cell count was associated with worse baseline REC (-6.72%; p=0.04) and CAL (9.06%; p<0.001). Further, lower nadir CD4+ T-cell count was associated with a greater relative longitudinal improvement in PPD in subjects with higher baseline levels of Porphyromonas gingivalis (p=0.027), and BOP in subjects with higher baseline levels of Porphyromonas gingivalis or Treponema denticola (p=0.001 and p=0.006 respectively). Longitudinal changes from baseline in CD4+ T-cell count and level of HIV RNA were not independently associated with longitudinal changes in any clinical markers of PD. Conclusion Degree of immunosuppression was associated with baseline gingival recession. After HAART initiation, measures of active PD improved most in those with lower nadir CD4+ T-cell counts and higher baseline levels of specific periodontopathogens. Nadir CD4+ T-cell count differentially influences periodontal disease both before and after HAART in HIV-infected adults. PMID:24146949

Vernon, Lance T.; Demko, Catherine A.; Babineau, Denise C.; Wang, Xuelei; Toossi, Zahra; Weinberg, Aaron; Rodriguez, Benigno

2013-01-01

73

Geosynchronous orbiting Nadir Etalon Sounding Spectrometer instrument concept for temperature, moisture and trace species, GeoNESS  

NASA Technical Reports Server (NTRS)

The paper describes the salient features of the Geosynchronous orbiting Nadir Etalon Sounding Spectrometer (GeoNESS) designed for applications from geosynchronous orbit for nadir sounding temperature, moisture, and trace species analyses in the troposphere and the lower stratosphere. Particular attention is given to the optics of GeoNESS, the optomechanical design, the cooling systems, the measurement approach used in GeoNESS, the channel selection, and the calibration considerations.

Kumer, J. B.; Sterritt, L. W.; Roche, A. E.; Morrow, H. E.; Willis, C. L.; Spradley, I. E.; Murray, D. O.; Shenk, W. E.; Susskind, J.

1992-01-01

74

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

SciTech Connect

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.

Barrette, J.; Kahana, S.

1983-01-01

75

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

NASA Astrophysics Data System (ADS)

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. Moreover, conjugated margins are often observed to be asymmetric in tectonic style. Regarding these objective we present an analysis of two W-E striking 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 Urania in spring 2010, within the framework of the MEDOC project. The lines cross the basin from the Corsica and Sardinia Margins towards the conjugated Latium and Campania Margins (Italy). The transects are divided in four zones distinguishable in tectonic style, velocity distribution, heat-flow and crustal thickness: 1) The deep sedimentary Corsica and Sardinia basins in the West which formed during Oligocene (~30 Ma) and reveal a fan-shaped sedimentary infill that is sealed by a Messinian erosional unconformity on top (~5-7 Ma). 2) Large rotated blocks bounding the deepest sub-basins along the entire transects and contain Messinian syn-tectonic sediments. 3) A zone of highly fractured continental crust broadens to the south and is indicated by a high number of faults and coincident with a velocity reduction. Furthermore, magmatic activity during Pliocene age in the southern line is evident in the southern line. 4) Flat summits at the Latium Margin indicate that this zone was above seal-level during rifting whereas the southern region was sub-sealevel. Faults cutting the seafloor indicate recent tectonic activity. To quantify the amount of horizontal extension we identified pre-, syn-, and post-tectonic sedimentary units in the northern line, 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 both sections 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 sediment is undisturbed and identified as the post-tectonic sequence except for the eastern region to the South (CD-line). Tomography of first arrivals obtained from wide-angle seismic data reveals the crustal architecture and thickness of 17 km ± 1 km along the northern profile. We found that the crust east of the Corsica Basin towards the Latium Margin is horizontally stretched by ~30 % and thinned vertically by the same amount (?-factor=1.3). Along the MEDOC-CD line the crustal has thinned by a factor of 1.5 in the vicinity of the Sardinia Basin and thins to a maximum of 2.2 (11 km) towards the mainland of Italy. Whereas the northern region has apparently stretched symmetrically, the higher stretched southern transect builds a pair of asymmetric conjugated margins.

Möller, Stefan; Grevemeyer, Ingo; Ranero, Cesar R.; Berndt, Christian; Klaeschen, Dirk; Sallares, Valenti; Zitellini, Nevio; de Franco, Roberto

2013-04-01

76

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

NASA Astrophysics Data System (ADS)

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.

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

77

Angles (elementary)  

NSDL National Science Digital Library

This lesson is designed to introduce students to acute, obtuse, and right angles. This lesson provides links to discussions and activities related to angles as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2010-01-01

78

Angle Hunting  

NSDL National Science Digital Library

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.

Exploratorium

2010-01-01

79

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

NASA Astrophysics Data System (ADS)

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.

Horváth, Ákos; Seethala, Chellappan; Deneke, Hartwig

2014-07-01

80

Angle Measurer  

NSDL National Science Digital Library

This Flash applet gives students practice in creating an angle measuring between zero and 180 degrees. Two buttons control the increase or decrease of the opening between two rays. Points are awarded for accuracy.

2011-01-01

81

Right Angle  

NSDL National Science Digital Library

This article gives teachers background information on right angles. It provides geometric and practical examples, a paper folding construction method, and some history of the usage of the term 'right.'

Goldenberg, Paul

2011-06-09

82

Relative and Absolute Calibration of a Multihead Camera System with Oblique and Nadir Looking Cameras for a Uas  

NASA Astrophysics Data System (ADS)

Numerous unmanned aerial systems (UAS) are currently flooding the market. For the most diverse applications UAVs are special designed and used. Micro and mini UAS (maximum take-off weight up to 5 kg) are of particular interest, because legal restrictions are still manageable but also the payload capacities are sufficient for many imaging sensors. Currently a camera system with four oblique and one nadir looking cameras is under development at the Chair for Geodesy and Geoinformatics. The so-called "Four Vision" camera system was successfully built and tested in the air. A MD4-1000 UAS from microdrones is used as a carrier system. Light weight industrial cameras are used and controlled by a central computer. For further photogrammetric image processing, each individual camera, as well as all the cameras together have to be calibrated. This paper focuses on the determination of the relative orientation between the cameras with the „Australis" software and will give an overview of the results and experiences of test flights.

Niemeyer, F.; Schima, R.; Grenzdörffer, G.

2013-08-01

83

Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four different inversion algorithms  

NASA Astrophysics Data System (ADS)

Four inversion schemes based on various retrieval approaches (digital gas correlation, nonlinear least squares, global fit adjustment, and neural networks) developed to retrieve CO from nadir radiances measured by such downward-looking satelliteborne instruments as the Measurement of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Infrared Atmospheric Sounding Interferometer (IASI) instruments were compared both for simulated cases and for atmospheric spectra recorded by the Interferometric Monitor for Greenhouse Gases (IMG). The sensitivity of the retrieved CO total column amount to properties that may affect the inversion accuracy (noise, ancillary temperature profile, and water-vapor content) was investigated. The CO column amounts for the simulated radiance spectra agreed within 4%, whereas larger discrepancies were obtained when atmospheric spectra recorded by the IMG instrument were analyzed. The assumed vertical temperature profile is shown to be a critical parameter for accurate CO retrieval. The instrument's line shape was also identified as a possible cause of disagreement among the results provided by the groups of scientists who are participating in this study.

Clerbaux, Cathy; Hadji-Lazaro, Juliette; Payan, Sebastien; Camy-Peyret, Claude; Wang, Jinxue; Edwards, David P.; Luo, Ming

2002-11-01

84

First results of proton antiproton annihilation into a pion pair at large scattering angles within the handbag approach  

NASA Astrophysics Data System (ADS)

We propose to describe the process p bar p ? ?+ ?- in a perturbative, QCD motivated framework in which a hard ud?bar d ? d bar d annihilation factorizes from soft transition distribution amplitudes. We advocate that the scale allowing for this factorization is the large transverse momentum transfer. In our simplified model, in which the proton is considered as a (scalar)diqark-quark system, a transition distribution amplitude describes the non-perturbative transition of the proton to the meson by emission of a scalar, isoscalar ud-diquark and absorption of an antiquark (analogously for bar p ? ?-). We model the transition distribution amplitudes as an overlap of light-cone wave functions and present first results for the differential cross section. This process will be measured by the PANDA experiment at GSI-FAIR.

Goritschnig, A. T.; Kofler, S.; Schweiger, W.

2014-04-01

85

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

Microsoft Academic Search

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

Guillem Chust; Yolanda Sagarminaga

2007-01-01

86

Estimating Angles  

NSDL National Science Digital Library

This Flash game for one or two players gives students practice in estimating the size of angles. A circle and a radius pointing in a random direction are given. The student activates a second sweeping radius, which can move in either direction, and tries to stop it at the specified measure. Three difficulty levels control the range of angle measures. Points are awarded based on closeness of the estimate. The Teachers' Notes page includes suggestions for implementation, discussion questions, ideas for extension and support.

2007-06-01

87

Early-stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide-angle and multichannel seismic study  

NASA Astrophysics Data System (ADS)

Extension of the continental lithosphere leads to the formation of rift basins and ultimately may create passive continental margins. The mechanisms that operate during the early stage of crustal extension are still intensely debated. We present the results from coincident multichannel seismic and wide-angle seismic profiles that transect across the northern Tyrrhenian Sea Basin. The profiles cross the Corsica Basin (France) to the Latium Margin (Italy) where the early-rift stage of the basin is well preserved. We found two domains, each with a distinct tectonic style, heat flow and crustal thickness. One domain is the Corsica Basin in the west that formed before the main rift phase of the northern Tyrrhenian Sea opening (˜8-4 Ma). The second domain is rifted continental crust characterized by tilted blocks and half-graben structures in the central region and at the Latium Margin. These two domains are separated by a deep (˜10 km) sedimentary complex of the eastern portion of the Corsica Basin. Travel-time tomography of wide-angle seismic data reveals the crustal architecture and a subhorizontal 15-17 ± 1 km deep Moho discontinuity under the basin. To estimate the amount of horizontal extension we have identified the pre-, syn-, and post-tectonic sedimentary units and calculated the relative displacement of faults. We found that major faults initiated at angles of 45°-50° and that the rifted domain is horizontally stretched by a factor of ? ˜ 1.3 (˜8-10 mm/a). The crust has been thinned from ˜24 to ˜17 km indicating a similar amount of extension (˜30%). The transect represents one of the best imaged early rifts and implies that the formation of crustal-scale detachments, or long-lived low-angle normal faults, is not a general feature that controls the rift initiation of continental crust. Other young rift basins, like the Gulf of Corinth, the Suez Rift or Lake Baikal, display features resembling the northern Tyrrhenian Basin, suggesting that half-graben formations and distributed homogeneous crustal thinning are a common feature during rift initiation.

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

2013-08-01

88

Rain rate estimation from nadir-looking TOPEX\\/POSEIDON microwave radiometer (TMR) for correction of radar altimetric measurements  

Microsoft Academic Search

Atmospheric liquid water, particularly in the form of rain, produces anomalies in the radar altimetric range measurements. Such features are observed as sudden large changes in radar backscatter as a means of identification. To quantify the rain that radar altimetric pulses encounter, the instantaneous rain estimation capability of the nadir looking multichannel microwave radiometer onboard the TOPEX\\/POSEIDON satellite is explored.

Atul Kumar Varma; Rakesh Mohan Gairola; C. M. Kishtawal; P. C. Pandey; K. P. Singh

1999-01-01

89

Detection Method of Lightning and TLEs by JEM-GLIMS Nadir Observation  

NASA Astrophysics Data System (ADS)

A scientific payload named JEM-GLIMS aboard the International Space Station (ISS) is aimed at observing lightning and Transient Luminous Events (TLEs) globally. Keeping its field-of-view toward the nadir direction, GLIMS clarifies the horizontal structures of lightning and TLEs, which is a crucial issue to understand the electrodynamic coupling between the troposphere and ionosphere. A difficult point, however, is that careful analyses are necessary to separate the emissions of lightning and TLEs which spatially overlap along the line-of-sights in the case of nadir observation. In this study, we analyze the multi-wavelength optical data obtained by GLIMS to identify lightning and TLEs. The main data analyzed are those of imager (LSI) and spectrophotometer (PH). LSI consists of two cameras equipped with a broadband red filter and a narrowband 762-nm filter, respectively, and obtains imagery at a spatial resolution of 400 m/pixel on the ground surface. PH detects time-resolved emission intensity at a sampling rate of 20 kHz by six photometer channels measuring at 150-280, 337, 762, 600-900, 316 and 392 nm, respectively. During a period between November 2012 and June 2013, GLIMS observed 815 lightning and/or TLE events, and in 494 of them, both LSI and PH data showed clear signals above the noise level. As the first step, we carried out case study using an event observed at 09:50:47UT on Jan 29 2013 which did not cause strong saturation on the LSI and PH data. The estimated peak irradiance was 1.38x10^(-3) W/m^(2) at 600-900 nm, which is equivalent to the top 10 % bright lightning events observed by FORTE satellite in the past. This finding suggests that GLIMS selectively observes the most optically-powerful events. The peak irradiance was estimated also for the other PH channels. At all visible channels other than a far ultra violet (FUV) channel, the peak irradiance was estimated to be in good agreement with the atmospheric transmittance curve calculated between 10 km and ISS altitude. We therefore primarily attribute the visible emissions of this event to lightning discharge occurring in the troposphere. Interestingly, GLIMS also detected the FUV emission which is significantly stronger than that expected for tropospheric lightning. This finding suggests that TLE also occurred at higher altitudes where the FUV emission is not affected by atmospheric attenuation. As such, it is clear that GLIMS is able to discriminate optical emissions of lightning and TLEs occurring in the nadir direction. In the conference, we will examine the identification technique in details and, by applying it to all the events, will discuss the validity and limitation.

Adachi, T.; Sato, M.; Ushio, T.; Yamazaki, A.; Suzuki, M.; Masayuki, K.; Takahashi, Y.; Inan, U.; Linscott, I.; Hobara, Y.

2013-12-01

90

Preliminary results for a large angle oblique jet impingement and flow and for the effect of initial conditions on the near field of an axisymmetric jet  

NASA Technical Reports Server (NTRS)

The structure of an axisymmetric jet in the near field is discussed for jet noise and for jet impingment schemes for STOL aircraft. It is inferred from previous studies, and the inference is supported by analysis, that the scale and intensity of the turbulence structure at the jet exit plane are the important boundary conditions which effect the development of the flow in the near field. The techniques to study these effects while maintaining a uniform mean flow and the results which document the range of the initial conditions are presented. The large angle, oblique jet impingment condition is of interest in terms of the jet/flap interaction. Detailed turbulence data can be obtained with the specially constructed facility. The development of the flow and instrumentation system and initial data from the new facility are presented.

Foss, J. F.; Kleis, S. J.

1973-01-01

91

Angle detector  

NASA Technical Reports Server (NTRS)

An angle detector for determining a transducer's angular disposition to a capacitive pickup element is described. The transducer comprises a pendulum mounted inductive element moving past the capacitive pickup element. The capacitive pickup element divides the inductive element into two parts L sub 1 and L sub 2 which form the arms of one side of an a-c bridge. Two networks R sub 1 and R sub 2 having a plurality of binary weighted resistors and an equal number of digitally controlled switches for removing resistors from the networks form the arms of the other side of the a-c bridge. A binary counter, controlled by a phase detector, balances the bridge by adjusting the resistance of R sub 1 and R sub 2. The binary output of the counter is representative of the angle.

Parra, G. T. (inventor)

1978-01-01

92

Characteristics of Deep Tropical and Subtropical Convection from Nadir-Viewing High-Altitude Airborne Doppler Radar  

NASA Technical Reports Server (NTRS)

This paper presents observations of deep convection characteristics in the tropics and subtropics that have been classified into four categories: tropical cyclone, oceanic, land, and sea breeze. Vertical velocities in the convection were derived from Doppler radar measurements collected during several NASA field experiments from the nadir-viewing high-altitude ER-2 Doppler radar (EDOP). Emphasis is placed on the vertical structure of the convection from the surface to cloud top (sometimes reaching 18-km altitude). This unique look at convection is not possible from other approaches such as ground-based or lower-altitude airborne scanning radars. The vertical motions from the radar measurements are derived using new relationships between radar reflectivity and hydrometeor fall speed. Various convective properties, such as the peak updraft and downdraft velocities and their corresponding altitude, heights of reflectivity levels, and widths of reflectivity cores, are estimated. The most significant findings are the following: 1) strong updrafts that mostly exceed 15 m/s, with a few exceeding 30 m/s, are found in all the deep convection cases, whether over land or ocean; 2) peak updrafts were almost always above the 10-km level and, in the case of tropical cyclones, were closer to the 12-km level; and 3) land-based and sea-breeze convection had higher reflectivities and wider convective cores than oceanic and tropical cyclone convection. In addition, the high-resolution EDOP data were used to examine the connection between reflectivity and vertical velocity, for which only weak linear relationships were found. The results are discussed in terms of dynamical and microphysical implications for numerical models and future remote sensors.

Heymsfield, Gerald M.; Tian, Lin; Heymsfield, Andrew J.; Li, Lihua; Guimond, Stephen

2010-01-01

93

Tropospheric water vapor retrieval from a nadir THz/FIR sounder  

NASA Astrophysics Data System (ADS)

This work presents clear-sky simulations to study water vapor (H2O) retrieval from a nadir sounder operating in the TeraHertz (THz) and Far-Infrared (FIR) spectral domains (100-500 cm-1). The THz/FIR retrieval is compared with retrieval from the mid-InfraRed (IR) 7?m H2O band (1200-2000 cm-1). The THz/FIR observations are more sensitive in the upper troposphere and lower stratosphere than the IR measurements. On the other hand, the IR sounder has better performance in the lower troposphere. The retrieval error due to uncertainties on the temperature profile are of the same order of magnitude in the THz/FIR and IR bands. No significant retrieval errors from contaminating species have been found. The calculations for several atmospheric scenarios show that retrieval performances are not only dependent on the H2O abundance but also on the temperature gradient. Hence, sensitivity in the UT/LS layer, with a low temperature gradient, is poor. The combination of FIR and IR merges the advantages of both bands, and allows to slightly decorrelate temperature and H2O VMR.

Baron, Philippe; Mendrok, Jana; Dupuy, Eric; Kasai, Yasuko

2008-12-01

94

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

NASA Technical Reports Server (NTRS)

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.

Heath, Donald; Georgiew, Georgi

2011-01-01

95

A randomized control trial to evaluate the effect of adjuvant selective laser trabeculoplasty versus medication alone in primary open-angle glaucoma: preliminary results  

PubMed Central

Background The objective of this study was to investigate the effects of adjuvant selective laser trabeculoplasty (SLT) versus medication alone on intraocular pressure (IOP) control, medication use, and quality of life in patients with primary open-angle glaucoma. Methods This prospective, randomized control study recruited 41 consecutive primary open-angle glaucoma subjects with medically-controlled IOP ?21 mmHg. The SLT group (n=22) received a single 360-degree SLT treatment. The medication-only group (n=19) continued with their usual treatment regimen. In both groups, medication was titrated to maintain a target IOP defined as a 25% reduction from baseline IOP without medication, or <18 mmHg, whichever was lower. Outcomes, which were measured at baseline and at 6 months, included the Glaucoma Quality of Life-15 (GQL-15) and Comparison of Ophthalmic Medications for Tolerability (COMTOL) survey scores, IOP, and the number of antiglaucoma medicines. Results The baseline IOP was 15.8±2.7 mmHg and 14.5±2.5 mmHg in the SLT and medication-only groups, respectively (P=0.04). Both groups had a comparable number of baseline medication (P=0.2), GQL-15 (P=0.3) and COMTOL scores (P=0.7). At 6 months, the SLT group had a lower IOP (P=0.03) and required fewer medications compared with both baseline (P<0.0001) and with the medication-only group (P=0.02). There was no statistically significant difference in the 6-month GQL-15 or COMTOL score as compared to baseline (P?0.4) or between the two treatment groups (P?0.2). Conclusion A single session of adjuvant SLT provided further reductions in IOP and medication without substantial changes in quality of life or medication tolerability at 6 months.

Lee, Jacky WY; Chan, Catherine WS; Wong, Mandy OM; Chan, Jonathan CH; Li, Qing; Lai, Jimmy SM

2014-01-01

96

Sun-view angle effects on reflectance factors of corn canopies  

NASA Technical Reports Server (NTRS)

The effects of sun and view angles on reflectance factors of corn (Zea mays L.) canopies ranging from the six leaf stage to harvest maturity were studied on the Purdue University Agronomy Farm by a multiband radiometer. The two methods of acquiring spectral data, the truck system and the tower systrem, are described. The analysis of the spectral data is presented in three parts: solar angle effects on reflectance factors viewed at nadir; solar angle effects on reflectance factors viewed at a fixed sun angle; and both sun and view angles effect on reflectance factors. The analysis revealed that for nadir-viewed reflectance factors there is a strong solar angle dependence in all spectral bands for canopies with low leaf area index. Reflectance factors observed from the sun angle at different view azimuth angles showed that the position of the sensor relative to the sun is important in determining angular reflectance characteristics. For both sun and view angles, reflectance factors are maximized when the sensor view direction is towards the sun.

Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.; Bauer, M. E.

1985-01-01

97

Evaluation of the Sensor Data Record from the nadir instruments of the Ozone Mapping Profiler Suite (OMPS)  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

98

Low earth orbiting Nadir Etalon Sounding Spectrometer instrument concept for temperature, moisture and trace species, LeoNESS  

NASA Technical Reports Server (NTRS)

A concept for a low earth orbiting nadir etalon spectrometer sounder (LeoNESS) is described which can achieve retrieval of temperature, H2O, surface, boundary conditions, cloudiness, and trace species with an accuracy that meets or exceeds the AIRS specifications. Options employing 65-K and 30-K detectors are examined; the former may be implemented via passive radiative cooling. The concept, which is derived from the Cryogenic Limb Array Etalon Spectrometer, has the potential for improving the horizontal and vertical resolution.

Kumer, J. B.; Sterritt, L. W.; Roche, A. E.; Rosenberg, W. J.; Morrow, H. E.; Shenk, W. E.; Susskind, J.

1992-01-01

99

View angle effects on relationships between MISR vegetation indices and leaf area index in a recently burned ponderosa pine forest  

Microsoft Academic Search

While nadir-viewing passive multispectral sensors have limited utility for characterizing the full dimensionality of forest canopies, multi-angle remote sensors such as the Multi-angle Imaging SpectroRadiometer (MISR) may improve detection of canopy architecture, canopy cover, and leaf area index (LAI) of forest canopy versus understory vegetation. Our objective was to determine whether data from the MISR sensor could improve estimates of

Amy Pocewicz; Lee A. Vierling; Leigh B. Lentile; Rachel Smith

2007-01-01

100

Ozone assimilation in the UTLS: Value of limb-viewing sounders and resolution-dependent analysis of nadir data  

NASA Astrophysics Data System (ADS)

The paper discusses aspects of the resolution-dependent analysis of ozone satellite data in the Upper Troposphere and Lower Stratosphere (UTLS) region. In this region the sharp positive and negative vertical ozone gradients are frequently observed by insitu measurements and simulated by chemistry-climate models, showing so-called ozone laminas. With sufficient vertical resolution of limb-viewing sensors, such as MLS and HIRDLS on Aura/NASA spacecraft, this information on ozone dynamics in thin vertical layers can be accepted by data assimilation systems constraining layered vertical ozone structures across the tropopause. For these scenes, the ozone-sensitive information from the nadir sensors (SBUV, GOME, TES, AIRS, OMI, IASI) characterized by restricted vertical resolution should be properly projected from the data space to the analysis grid preserving the non-observable (but forecasted) ozone vertical structures. Several illustrations for analysis of nadir-only ozone data (SBUV-2) that can "diffuse" ozone laminas in the extra-tropical UTLS are discussed. To overcome this negative impact of analysis of nadir data, the resolution-dependent analysis schemes (RDAS) of retrievals (characterized by kernels) or/and radiances are suggested. The vertical inverse mapping performed by RDAS ensures constraining only scales observable by data preserving the non-observable short-scale vertical structures of ozone. As illustrated by comparisons of MLS and HIRDLS data with analyzed ozone fields (GEOS-5 and ECMWF), the other geophysical scenes influenced by inadequate assimilation of nadir retrievals may include: a) the high-latitude ozone hole and mini-holes; b) seasonal and quasi-biennial ozone oscillations in the tropical stratosphere; c) movements of high and low ozone air masses across the transport barriers. These comparisons demonstrate the value of MLS and HIRDLS limb data in constraining of ozone for monitoring atmospheric composition and climate. The current plans for analysis of MLS radiance data in GEOS-5 data assimilation system are highlighted along with resolution-sensitive assimilation of ozone partial columns provided by nadir sensors.

Yudin, Valery; Pawson, Steven; Reinecker, Michele; Xu, Philippe; Sienkiewicz, Meta; Gille, John; Kinnison, Douglas; Livesey, Nathaniel

2010-05-01

101

Using multi-angle, multispectral photo-polarimetry of the NASA Glory mission to constrain optical properties of aerosols and clouds: Results from  

E-print Network

Using multi-angle, multispectral photo-polarimetry of the NASA Glory mission to constrain optical or absorbing sunlight ("direct climate forcing") and by modifying the formation and life-cycle of clouds) instrument to monitor the changes in total solar irradiance (TSI) incident on the atmosphere of the Earth

102

Small-angle X-ray characterization of the nucleoprotein complexes resulting from DNA-induced oligomerization of HIV1 integrase  

Microsoft Academic Search

HIV-1 integrase (IN) catalyses integration of a DNA copy of the viral genome into the host genome. Specific interactions between retroviral IN and long terminal repeats (LTR) are required for this insertion. To characterize quantitatively the influence of the determinants of DNA substrate specificity on the oligomerization status of IN, we used the small- angle X-ray scattering (SAXS) technique. Under

Svetlana Baranova; Fedor V. Tuzikov; Olga D. Zakharova; Natalia A. Tuzikova; Christina Calmels; Simon Litvak; Laura Tarrago-Litvak; Vincent Parissi; Georgy A. Nevinsky

2007-01-01

103

NOMAD, a spectrometer suite for Nadir and Solar Occultation observations on the ExoMars Trace Gas Orbiter  

NASA Astrophysics Data System (ADS)

NOMAD, the "Nadir and Occultation for MArs Discovery" spectrometer suite has been selected by ESA and NASA to be part of the payload of the ExoMars Trace Gas Orbiter mission 2016. This instrument suite will conduct a spectroscopic survey of Mars' atmosphere in the UV, visible and IR regions covering the 0.2-0.65 and 2.2-4.3 ?m spectral ranges. NOMAD's observation modes include solar occultation, nadir and limb observations. The NOMAD instrument is composed of 3 channels: a solar occultation only channel (SO) operating in the infrared wavelength domain, a second infrared channel capable of doing nadir, but also solar occultation and limb observations (LNO), and an ultraviolet/visible channel (UVIS) that can work in all observation modes. The spectral resolution of SO and LNO surpasses previous surveys in the infrared by more than one order of magnitude. NOMAD offers an integrated instrument combination of a flight-proven concept (SO is a copy of SOIR on Venus Express), and innovations based on existing and proven instrumentation (LNO is based on SOIR/VEX and UVIS has heritage from the ExoMars lander), that will provide mapping and vertical profile information at high spatio-temporal resolution. The three channels have each their own ILS and optical bench, but share the same single interface to the S/C. We will present the instrument and its capabilities in term of detection of a broad suite of species, its possibilities to improve our knowledge on vertical structure of the atmosphere as well as its mapping possibilities.

Vandaele, A. C.; López-Moreno, J.-J.; Patel, M. R.; Bellucci, G.; Daerden, F.; Drummond, R.; Neefs, E.; Robert, S.; Rodriguez Gomez, J.

2012-04-01

104

NOMAD, a spectrometer suite for Nadir and Solar Occultation observations on the ExoMars Trace Gas Orbiter  

NASA Astrophysics Data System (ADS)

NOMAD, the "Nadir and Occultation for MArs Discovery" spectrometer suite was selected as part of the payload of the ExoMars Trace Gas Orbiter mission 2016. This instrument suite will conduct a spectroscopic survey of Mars' atmosphere in the UV, visible and IR regions covering the 0.2-0.65 and 2.2-4.3 µm spectral ranges. NOMAD's observation modes include solar occultation, nadir and limb observations. The NOMAD instrument is composed of 3 channels: a solar occultation only channel (SO) operating in the infrared wavelength domain, a second infrared channel capable of doing nadir, but also solar occultation and limb observations (LNO), and an ultraviolet/visible channel (UVIS) that can work in all observation modes. The spectral resolution of SO and LNO surpasses previous surveys in the infrared by more than one order of magnitude. NOMAD offers an integrated instrument combination of a flight-proven concept (SO is a copy of SOIR on Venus Express), and innovations based on existing and proven instrumentation (LNO is based on SOIR/VEX and UVIS has heritage from the ExoMars lander), that will provide mapping and vertical profile information at high spatio-temporal resolution. The three channels have each their own ILS and optical bench, but share the same single interface to the S/C. We will present the instrument and its capabilities in term of detection of a broad suite of species, its possibilities to improve our knowledge on vertical structure of the atmosphere as well as its mapping possibilities. Since last year's abstract, much progress has been made on the instrument design and prototypes have been tested, especially concerning the very challenging thermal needs of the instrument. This paper will concentrate on the developments in the last year that prove NOMAD will be a very powerful, sensitive instrument.

Drummond, Rachel; Robert, Severine; Vandaele, Ann-Carine; Willame, Yannick; Lopez-Moreno, Jose Juan; Patel, Manish; Belluci, Giancarlo; Daerden, Frank; Neefs, Eddy; Rodriguez-Gomez, Julio

2013-04-01

105

Utility of BRDF Models for Estimating Optimal View Angles in Classification of Remotely Sensed Images  

NASA Technical Reports Server (NTRS)

Statistical classification of remotely sensed images attempts to discriminate between surface cover types on the basis of the spectral response recorded by a sensor. It is well known that surfaces reflect incident radiation as a function of wavelength producing a spectral signature specific to the material under investigation. Multispectral and hyperspectral sensors sample the spectral response over tens and even hundreds of wavelength bands to capture the variation of spectral response with wavelength. Classification algorithms then exploit these differences in spectral response to distinguish between materials of interest. Sensors of this type, however, collect detailed spectral information from one direction (usually nadir); consequently, do not consider the directional nature of reflectance potentially detectable at different sensor view angles. Improvements in sensor technology have resulted in remote sensing platforms capable of detecting reflected energy across wavelengths (spectral signatures) and from multiple view angles (angular signatures) in the fore and aft directions. Sensors of this type include: the moderate resolution imaging spectroradiometer (MODIS), the multiangle imaging spectroradiometer (MISR), and the airborne solid-state array spectroradiometer (ASAS). A goal of this paper, then, is to explore the utility of Bidirectional Reflectance Distribution Function (BRDF) models in the selection of optimal view angles for the classification of remotely sensed images by employing a strategy of searching for the maximum difference between surface BRDFs. After a brief discussion of directional reflect ante in Section 2, attention is directed to the Beard-Maxwell BRDF model and its use in predicting the bidirectional reflectance of a surface. The selection of optimal viewing angles is addressed in Section 3, followed by conclusions and future work in Section 4.

Valdez, P. F.; Donohoe, G. W.

1997-01-01

106

What's the Angle?  

NSDL National Science Digital Library

This classroom activity helps 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 helps students use the experiment results to gain a deeper understanding of seasonal temperature changes and why Antarctica is always so cold.

107

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.

108

Erratum: First Results from the Wide Angle Camera of the ROSETTA Mission [Mem.SAIt Suppl. 6, 28-33 (2005)  

NASA Astrophysics Data System (ADS)

The authors acknowledge that the paper fails to convey the correct information about the respective contributions and roles of the partners of the OSIRIS consortium. In particular, the hardware contributions of the Max-Planck Institut für Sonnensystemforschung, MPS, (Katlenburg Lindau, Germany, formerly MPAe), of the Instituto de Astrofisica de Andalucia (Granada, Spain), of the Department of Astronomy and Space Physics of Uppsala University (DASP), of ESA Research and Scientific Support Department (ESA/RSSD) to the Wide Angle Camera has not been mentioned or incorrectly expounded. The overall responsibility (PI ship) of MPS (MPAe) for OSIRIS and hence for the Wide Angle Camera is not correctly mentioned either. The correct information is given in the paper by Keller et al. (2006, Space Science Review, in press). The authors take this opportunity to acknowledge that the activity of the Italian team has been partly supported by the Italian Space Agency ASI through a contract to CISAS.

Barbieri, C.; Fornasier, S.; Bertini, I.; Angrilli, F.; Bianchini, G. A.; Debei, S.; de Cecco, M.; Parzianello, G.; Zaccariotto, M.; da Deppo, V.; Naletto, G.

109

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)

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.

Rothermel, Jeffry

1987-01-01

110

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

111

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

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

112

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

113

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

USGS Publications Warehouse

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) maxima up to our observation limit of 16 A??-1. The type of counter ion used during synthesis produces no significant change in this function. In unarsenated samples, Radial Distribution Functions (RDFs) produced from the scattering functions show a well-defined Fe-O peak at 2.02 A?? in excellent agreement with the mean distance of 2.01 A?? from extended X-ray absorption fine structure (EXAFS) analysis. The area under the Fe-O peak is consistent with only octahedral oxygen coordination about iron, and an iron coordination about oxygen of 2.2, in agreement with the EXAFS results, the sample composition, and XANES measurements. The second peak observed in the RDFs is clearly divided into two populations of correlations, at 3.07 and 3.52 A??, respectively. These distances are close to the EXAFS-derived Fe-Fe subshell distances of 3.02-3.05 and 3.43-3.46 A??, respectively, though this is misleading as the RDF peaks also include contributions from O-Fe and O-O correlations. Simulated RDFs of the FeOOH polymorphs indicate how the observed RDF structure relates to the EXAFS pair-correlation function, and allow comparisons with an ordered ferrihydrite structure. The effect of increasing arsenate content is dramatic, as the RDF peaks are progressively smeared out, indicating a wider range of interatomic distances even at moderate surface coverages, and a loss of longer range correlations. At an As/Fe ratio of 0.68, the surface saturation level of arsenate, the RDF shows little order beyond what would be expected from small pieces of dioctahedral Fe oxyhydroxyl chains or small "sheet" units. Analysis of the first RDF peak yields components due to As-O and Fe-O correlations. As the As-O component at 1.67 A?? increases in size, the Fe-O component decreases, reflecting a decrease in Fe coordination about the average oxygen. This reduction is consistent with a decrease in mean crystallite size as suggested by EXAFS studies. Analysis of the second RDF peak components shows the progressive decrease in Fe-Fe correlations, and the enhancement of As-Fe correlations, as arsenate level increases. Comparison of the experimental RDF from coprecipitated arsenate-saturated FHY2 with simulated RDFs of model iron oxyhydroxyl structures further constrains possible sizes and geometry for the precipitates, and is consistent with sorbed complexes of the bidentate binuclear (apical oxygen sharing) type.

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

1996-01-01

114

Generalization of the Euler Angles  

NASA Technical Reports Server (NTRS)

It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.

Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis

2002-01-01

115

The Feasibility of Tropospheric and Total Ozone Determination Using a Fabry-Perot Interferometer as a Satellite - Nadir-Viewing Atmospheric Sensor.  

NASA Astrophysics Data System (ADS)

Monitoring of the global distribution of tropospheric ozone (O_3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O_3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O_3 measurements can simultaneously observe a stratospheric component and thus the total O_3 column abundance. Decreasing stratospheric O_3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately.068 cm^{-1}. A spectral region of about 1 cm^{-1} wide centered at 1054.73 cm^{ -1} within the strong 9.6 mu m ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis assessing the impact on retrieved O_3 amounts of the most significant uncertainties associated with this particular measurement has been performed for several different types of atmospheres. Results show the proposed instrumentation to enable a good measurement of absolute ozone amounts and an even better determination of relative changes, with a range of accuracy to within 7.55 to 20.6% for integrated tropospheric amounts (and 1.99 to 4.02% for total O _3 column abundance) and a corresponding range in precision to within 7.73 to 10.4% (and 3.30 to 3.95% for total O_3 column abundance), for the atmospheric conditions considered.

Larar, Allen Maurice

116

The feasibility of tropospheric and total ozone determination using a Fabry-Perot interferometer as a satellite-based nadir-viewing atmospheric sensor  

NASA Astrophysics Data System (ADS)

Monitoring of the global distribution of tropospheric ozone (O3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot Interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance. Decreasing stratospheric O3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). A spectral region of about 1 cm(exp -1) wide centered at 1054.73 cm(exp -1) within the strong 9.6 micron ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis assessing the impact on retrieved O3 amounts of the most significant uncertainties associated with this particular measurement has been performed for several different types of atmospheres. Results show the proposed instrumentation to enable a good measurement of absolute ozone amounts and an even better determination of relative changes, with a range of accuracy to within 7.55 to 20.6 percent for integrated tropospheric amounts (and 1.99 to 4.02 percent for total O3 column abundance) and a corresponding range in precision to within 7.73 to 10.4 percent (and 3.30 to 3.95 percent for total O3 column abundance), for the atmospheric conditions considered.

Larar, Allen Maurice

1993-01-01

117

The Feasibility of Tropospheric and Total Ozone Determination Using a Fabry-perot Interferometer as a Satellite-based Nadir-viewing Atmospheric Sensor. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

Monitoring of the global distribution of tropospheric ozone (O3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot Interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance. Decreasing stratospheric O3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). A spectral region of about 1 cm(exp -1) wide centered at 1054.73 cm(exp -1) within the strong 9.6 micron ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis assessing the impact on retrieved O3 amounts of the most significant uncertainties associated with this particular measurement has been performed for several different types of atmospheres. Results show the proposed instrumentation to enable a good measurement of absolute ozone amounts and an even better determination of relative changes, with a range of accuracy to within 7.55 to 20.6 percent for integrated tropospheric amounts (and 1.99 to 4.02 percent for total O3 column abundance) and a corresponding range in precision to within 7.73 to 10.4 percent (and 3.30 to 3.95 percent for total O3 column abundance), for the atmospheric conditions considered.

Larar, Allen Maurice

1993-01-01

118

VHF Radar Measurements of Tropical Forests in Panama: Results from the BioSAR Deployment in Central America  

NASA Technical Reports Server (NTRS)

A synthetic aperture radar sensor operating in 5 bands between 80 and 120 MHz was flown over forested areas in the canal zone of the Republic of Panama in an experiment to measure biomass in heavy tropical forests. The sensor is a pulse coherent SAR flown on a small aircraft and oriented straight down. The doppler history is processed to collect data on the ground in rectangular cells of varying size over a range of incidence angles fore and aft of nadir (+45 to - 45 degrees). Sensor data consists of 5 frequency bands with 20 incidence angles per band. Sensor data for over 12+ sites were collected with forest stands having biomass densities ranging from 50 to 300 tons/ha dry above ground biomass. Results are shown exploring the biomass saturation thresholds using these frequencies, the system design is explained, and preliminary attempts at data visualization using this unique sensor design are described.

Imhoff, Marc; Lawrence, William; Condit, Richard; Wright, Joseph; Johnson, Patrick; Holford, Warren; Hyer, Joseph; May, Lisa; Carson, Steven

2000-01-01

119

Small Angle Neutron Scattering  

SciTech Connect

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.

Urban, Volker S [ORNL

2012-01-01

120

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

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

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

2002-01-01

121

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

NASA Technical Reports Server (NTRS)

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.

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

1971-01-01

122

MISR Multi-angle Views of Sunday Morning Fires  

NASA Technical Reports Server (NTRS)

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.

2007-01-01

123

Angles and Area  

NSDL National Science Digital Library

In this activity (page 10 of PDF), learners approximate the area of the uppermost cross section of an impact crater using a variety of square grids. They conclude which angle of impact results in the greatest area. 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. Includes a pre-lesson activity (p54). The Moon Math: Craters! guide follows a 5E approach, applying concepts of geometry, modeling, data analysis to the NASA lunar spacecraft mission, LCROSS.

Nasa

2012-05-08

124

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

NASA Astrophysics Data System (ADS)

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.

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

1999-12-01

125

Describe Angle Pair Relationships  

NSDL National Science Digital Library

This lesson will explain the types of pairs of angles you will find in Geometry. Note taking time on page 5: Angle Information Now, let's see if you get it: Angle Relationship Quiz (fun) Ok! Now for your assignment, #8 on page 38! Class Zone Geometry Textbook ...

Neubert, Mrs.

2011-09-01

126

What's Your Angle?  

NSDL National Science Digital Library

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.

2010-01-01

127

Angles All Around  

NSDL National Science Digital Library

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 ...

Bennett, Mrs.

2011-12-14

128

Extreme-Risk Prostate Adenocarcinoma Presenting With Prostate-Specific Antigen (PSA) >40 ng/ml: Prognostic Significance of the Preradiation PSA Nadir  

SciTech Connect

Purpose: To examine the impact of patient, disease, and treatment characteristics on survival outcomes in patients treated with neoadjuvant androgen deprivation therapy (ADT) and radical external-beam radiotherapy (RT) for clinically localized, extreme-risk prostate adenocarcinoma with a presenting prostate-specific antigen (PSA) concentration of >40 ng/ml. Methods and Materials: A retrospective chart review was conducted of 64 patients treated at a single institution between 1991 and 2000 with ADT and RT for prostate cancer with a presenting PSA level of >40 ng/ml. The effects of patient age, tumor (presenting PSA level, Gleason score, and T stage), and treatment (total ADT duration and pre-RT PSA level) characteristics on rates of biochemical disease-free survival (bDFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were examined. Results: Median follow-up time was 6.45 years (range, 0.09-15.19 years). Actuarial bDFS, PCSS, and OS rates at 5 years were 39%, 87%, and 78%, respectively, and 17%, 64%, and 45%, respectively, at 10 years. On multivariate analysis, the pre-RT PSA level ({<=}0.1 versus >0.1 ng/ml) was the single most significant prognostic factor for bDFS (p = 0.033) and OS (p = 0.018) rates, whereas age, T stage, Gleason score, and ADT duration ({<=}6 versus >6 months) were not predictive of outcomes. Conclusion: In prostate cancer patients with high presenting PSA levels, >40 ng/ml, treated with combined modality, neoadjuvant ADT, and RT, the pre-RT PSA nadir, rather than ADT duration, was significantly associated with improved survival. This observation supports the use of neoadjuvant ADT to drive PSA levels to below 0.1 ng/ml before initiation of RT, to optimize outcomes for patients with extreme-risk disease.

Alexander, Abraham S. [British Columbia Cancer Agency, Vancouver Island Centre, Radiation Therapy Program, Victoria, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); Mydin, Aminudin; Jones, Stuart O.; Christie, Jennifer [British Columbia Cancer Agency, Vancouver Island Centre, Radiation Therapy Program, Victoria, British Columbia (Canada); Lim, Jan T.W. [British Columbia Cancer Agency, Vancouver Island Centre, Radiation Therapy Program, Victoria, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); Truong, Pauline T., E-mail: ptruong@bccancer.bc.ca [British Columbia Cancer Agency, Vancouver Island Centre, Radiation Therapy Program, Victoria, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); Ludgate, Charles M. [British Columbia Cancer Agency, Vancouver Island Centre, Radiation Therapy Program, Victoria, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada)

2011-12-01

129

Observation of the process. nu. \\/sub. mu. \\/ + e⁻. -->. nu. \\/sub. mu. \\/ + e⁻ at high energies. [Preliminary results, Weinberg-Salam model, mixing angle  

Microsoft Academic Search

There were 5 events of the reaction ..nu..\\/sub ..mu..\\/ + e⁻ ..-->.. ..nu..\\/sub ..mu..\\/ + e⁻ in a sample of approximately 50,000 charged current neutrino interactions in a heavy neon-hydrogen mixture in the 15 foot bubble chamber at Fermilab. This result is in rough agreement with the prediction of the Weinberg-Salam model with the currently favored value of the mixing

C. Baltay; D. Caroumbalis

1978-01-01

130

A Nadir-adjusted Airborne Multi Spectral Imaging System (NAMSIS) for high-resolution remote sensing of carbon fluxes  

NASA Astrophysics Data System (ADS)

Satellite remote sensing is widely used in vegetation monitoring, water stress detection and carbon cycle modeling. However, image pixels from high temporal resolution satellite sensors (such as MODIS) have coarse spatial resolution, much larger than the canopies they are supposed to characterize. An alternative solution for on-demand high spatial resolution remote sensing is sensors onboard low-flying aircrafts. Airborne remote sensing has been traditionally used in crop management studies. In this presentation we demonstrate the application of a relatively low-cost airborne sensor system with customized spectral band combinations for studying forest carbon fluxes. Our team has developed an Inertia Measurement Unit (IMU) controlled automated system to detach aircraft movements (pitch and roll) and engine vibration from the six-band programmable imager, in order to maintain the sensor at nadir view at all times during the flight. Flight lines are configured by a GPS-controleld system to simulate MODIS pixels. A feature-based algorithm is used to automatically generate a mosaic of individual images along the flight lines. This algorithm eliminates the need to mosiac and georeference images manually. An empirical line method is used to calculate reflectance from the raw data. Images from this airborne system produce reflectance values that are comparable with MODIS reflectance product. These high spatial resolution (~0.5 m) images deliver detailed information about tree species and phenological conditions within each MODIS pixel, and thus permit a high resolution spatio-temporal assessment of forest carbon fluxes.

Jiang, Z.; Scott, S.; Rahman, A. F.

2012-12-01

131

Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four  

E-print Network

as the Measurement of Pollution in the Troposphere MOPITT , the Tropospheric Emission Spectrometer TES of the retrieved CO total column amount to properties that may affect the inversion accuracy noise, ancillary cause of disagreement among the results provided by the groups of scientists who are participating

132

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.

133

Rain Fallspeeds and Rates Derived from Airborne Nadir-Pointing Doppler Radar Measurements  

NASA Technical Reports Server (NTRS)

The use of vertical-incidence Doppler velocity in addition to radar reflectivity may yield information on drop size distribution and therefore result in better rainrate estimates. Doppler velocity can provide useful information on the raindrop size distribution. Doppler velocities from a zenith-pointing radar represent the sum of the mean reflectivity-weighted hydrometeor fallspeed and the vertical air motion. Dual-parameter rain estimation methods using the Doppler velocity, require that the latter can be removed, or is negligible. Atlas et al. (1972) derived relations between Doppler velocity, reflectivity, and rain rate assuming an exponential size distribution for rain. Ulbrich (1994) expanded on this work by deriving the relation between the Doppler velocity and the reflectivity assuming a Gamma size distribution. This distribution provides a more realistic representation of the small rain drops. To get accurate information on raindrop size distributions with the above method, the air motions must be removed from the observed Doppler velocities

Heymsfield, Gerald M.; Tian, L.; Geerts, Bart

1999-01-01

134

Measures on Mixing Angles  

E-print Network

We address the problem of the apparently very small magnitude of CP violation in the standard model, measured by the Jarlskog invariant J. In order to make statements about probabilities for certain values of J, we seek to find a natural measure on the space of Kobayashi-Maskawa matrices, the double quotient U(1)^2\\SU(3)/U(1)^2. We review several possible, geometrically motivated choices of the measure, and compute expectation values for powers of J for these measures. We find that different choices of the measure generically make the observed magnitude of CP violation appear finely tuned. Since the quark masses and the mixing angles are determined by the same set of Yukawa couplings, we then do a second calculation in which we take the known quark mass hierarchy into account. We construct the simplest measure on the space of 3 x 3 Hermitian matrices which reproduces this known hierarchy. Calculating expectation values for powers of J in this second approach, we find that values of J close to the observed value are now rather likely, and there does not seem to be any fine tuning. Our results suggest that the choice of Kobayashi-Maskawa angles is closely linked to the observed mass hierarchy. We close by discussing the corresponding case of neutrinos.

Gary W. Gibbons; Steffen Gielen; C. N. Pope; Neil Turok

2008-10-27

135

Measures on mixing angles  

SciTech Connect

We address the problem of the apparently very small magnitude of CP violation in the standard model, measured by the Jarlskog invariant J. In order to make statements about probabilities for certain values of J, we seek to find a natural measure on the space of Kobayashi-Maskawa matrices, the double quotient U(1){sup 2}/SU(3)/U(1){sup 2}. We review several possible, geometrically motivated choices of the measure, and compute expectation values for powers of J for these measures. We find that different choices of the measure generically make the observed magnitude of CP violation appear finely tuned. Since the quark masses and the mixing angles are determined by the same set of Yukawa couplings, we then do a second calculation in which we take the known quark mass hierarchy into account. We construct the simplest measure on the space of 3x3 Hermitian matrices which reproduces this known hierarchy. Calculating expectation values for powers of J in this second approach, we find that values of J close to the observed value are now rather likely, and there does not seem to be any fine-tuning. Our results suggest that the choice of Kobayashi-Maskawa angles is closely linked to the observed mass hierarchy. We close by discussing the corresponding case of neutrinos.

Gibbons, Gary W.; Gielen, Steffen [D.A.M.T.P., Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Pope, C. N. [D.A.M.T.P., Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, Texas 77843-4242 (United States); Turok, Neil [D.A.M.T.P., Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, Ontario, Canada N2L 2Y5 (Canada)

2009-01-01

136

Neural network cloud screening algorithm Part II: global synthetic cases using high resolution spectra in O2 and CO2 near infrared absorption bands in nadir and sun glint  

NASA Astrophysics Data System (ADS)

In Part I a set of two layer feed-forward neural networks, trained via back propagation of sensitivities, was applied to a synthetic set of radiances in micro-windows of the near-infrared to make predictions of cloud water (cw), cloud ice (ci), effective scattering heights of cloud water and ice, (pcw and pci, respectively) and the column water vapor (w). A threshold test, using 2 g/m-2 for cloud water and 10 g/m-2 for cloud ice, was applied to the retrieved values to distinguish clear from cloudy scenes. In that work the discussion was limited to the nadir viewing geometry, and was applied only to land surfaces, excluding desert and snow and ice fields. Part II describes the extension to a set of high resolution radiances, as might be measured by a grating spectrometer from space, in both nadir and sun glint viewing geometries. Furthermore, results are given for all land surface types as well as scenes over ocean. Prior to neural network training, a Principal Component Analysis (PCA) is applied to the high resolution spectra, which consist of three bands centered at 0.76?m (O2 A-band), 1.61?m (weak CO2 band) and 2.06?m (strong CO2 band), each with 1016 channels. Analysis shows that the five leading EOFs together capture 99.9% of the variance in each band, reducing the data size by more than two orders of magnitude. Application of the trained neural networks to an independent data set, generated using CloudSat and Calipso cloud and aerosol profiles, as well as carbon dioxide profiles from a chemical transport model, were used to quantify the skill in the retrieval. The results vary significantly with surface type, viewing mode and cloud properties. Accuracies range from 7% to 100% (typically close to 75%), with confidence levels almost always greater than 90%.

Taylor, Thomas E.; O'Brien, D. M.

2010-03-01

137

Individualized optimal release angles in discus throwing.  

PubMed

The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques. PMID:19939389

Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing

2010-02-10

138

The Retroacetabular Angle Determines the Safe Angle for Screw Placement in Posterior Acetabular Fracture Fixation  

PubMed Central

Introduction. A method for the determination of safe angles for screws placed in the posterior acetabular wall based on preoperative computed tomography (CT) is described. It defines a retroacetabular angle and determines its variation in the population. Methods. The retroacetabular angle is the angle between the retroacetabular surface and the tangent to the posterior acetabular articular surface. Screws placed through the marginal posterior wall at an angle equal to the retroacetabular angle are extraarticular. Medial screws can be placed at larger angles whose difference from the retroacetabular angle is defined as the allowance angles. CT scans of all patients with acetabular fractures treated in our institute between September 2002 to July 2007 were used to measure the retroacetabular angle and tangent. Results. Two hundred thirty one patients were included. The average (range) age was 42 (15–74) years. The average (range) retroacetabular angle was 39 (30–47) degrees. The average (range) retroacetabular tangent was 36 (30–45)?mm. Conclusions. Placing the screws at an average (range) angle of 39 (33–47) degrees of anterior inclination with the retroacetabular surface makes them extraarticular. Angles for medial screws are larger. Safe angles can be calculated preoperatively with a computer program. PMID:24959359

Tadros, Ayman M. A.; Oxland, Thomas R.; O'Brien, Peter

2013-01-01

139

Results.  

ERIC Educational Resources Information Center

Describes the Collegiate Results Instrument (CRI), which measures a range of collegiate outcomes for alumni 6 years after graduation. The CRI was designed to target alumni from institutions across market segments and assess their values, abilities, work skills, occupations, and pursuit of lifelong learning. (EV)

Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

2001-01-01

140

Polygon Angle Applet  

NSDL National Science Digital Library

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.

Exner, Nicholas

2000-05-31

141

What's My Angle?  

NSDL National Science Digital Library

This interactive module offers learners the opportunity to check their knowledge of angle measure and estimation, and the use of a protractor. There are ten activities that vary the tasks and the degree of precision. The site is designed for whiteboard demonstration as well, and it includes a tutorial on angle types and protractor use.

2011-01-01

142

SunAngle Calculator  

NSDL National Science Digital Library

SunAngle is an on-line tool that calculates solar angles and related information for a given location, date, and time. It computes the declination of the Sun, sunrise and sunset times, azimuth of the Sun, solar time and more. Complete instructions and definitions of variables are included.

Gronbeck, Christopher

143

Special Angle Pairs Discovery Activity  

NSDL National Science Digital Library

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.

Henry, Barbara

2012-04-16

144

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

145

'Magic Angle Precession'  

SciTech Connect

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.

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

2008-01-21

146

Signature extension for sun angle, volume 1  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

147

Detecting blind building façades from highly overlapping wide angle aerial imagery  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

148

Tree branch angle: maximizing effective leaf area.  

PubMed

In a computer simulation of branching pattern and leaf cluster in Terminalia catappa, right and left branch angles were varied, and the effective leaf surface areas were calculated. Theoretical branch angles that result in maximum effective leaf area are close to the values observed in nature. PMID:17757590

Honda, H; Fisher, J B

1978-02-24

149

Tree Branch Angle: Maximizing Effective Leaf Area  

Microsoft Academic Search

In a computer simulation of branching pattern and leaf cluster in Terminalia catappa, right and left branch angles were varied, and the effective leaf surface areas were calculated. Theoretical branch angles that result in maximum effective leaf area are close to the values observed in nature.

Hisao Honda; Jack B. Fisher

1978-01-01

150

Using Inscribed Angles and Polygons  

NSDL National Science Digital Library

This unit will teach you about inscribed angles, intercepted arcs, their measures, inscribed polygons, and their associated theorems. OK, time for notes! Define Inscribed Angles, using the following website (Only define the inscribed angle from this site): Inscribed Angle Definition Using this new idea, you can use the following activity to figure out the formula for the measure of an inscribed angle: Inscribed Angle Formula Discovery The whole lesson depends upon this definition. Define Intercepted Arc, Inscribed polygons, ...

Neubert, Mrs.

2011-03-10

151

Divergent-ray projection method for measuring the flapping angle, lag angle, and torsional angle of a bumblebee wing  

NASA Astrophysics Data System (ADS)

A divergent-ray projection (DRP) method was developed for measuring the flapping angle, lag angle, and torsional angle of bumblebee wing during beating motion. This new method can measure the spatial coordinates of an insect wing by digitizing the images that are projected by two divergent laser rays from different directions. The advantage of the DRP method is its ability to measure those three angles simultaneously using only one high-speed camera. The resolution of the DRP method can be changed easily by adjusting system parameters to meet the needs of different types of objects. The measurement results for these angles of a bumblebee wing probe the effectiveness of the DRP method in studying the flight performance of insects.

Zeng, Lijiang; Matsumoto, Hirokazu; Kawachi, Keiji

1996-11-01

152

Supercritical Angle Fluorescence Correlation Spectroscopy  

PubMed Central

We explore the potential of a supercritical angle (SA) objective for fluorescence correlation spectroscopy (FCS). This novel microscope objective combines tight focusing by an aspheric lens with strong axial confinement of supercritical angle fluorescence collection by a parabolic mirror lens, resulting in a small detection volume. The tiny axial extent of the detection volume features an excellent surface sensitivity, as is demonstrated by diffusion measurements in model membranes with an excess of free dye in solution. All SA-FCS measurements are directly compared to standard confocal FCS, demonstrating a clear advantage of SA-FCS, especially for diffusion measurements in membranes. We present an extensive theoretical framework that allows for accurate and quantitative evaluation of the SA-FCS correlation curves. PMID:17827221

Ries, Jonas; Ruckstuhl, Thomas; Verdes, Dorinel; Schwille, Petra

2008-01-01

153

Skylab S-193 radar altimeter experiment analyses and results  

NASA Technical Reports Server (NTRS)

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.

Brown, G. S. (editor)

1977-01-01

154

Find Angle Measures in Polygons  

NSDL National Science Digital Library

This lesson will introduce you to polygons and their angle measures. Focus on the Interior angles and exterior angles and their properties. First, let's discuss diagonals. What is a diagonal in a polygon? Play with and take notes on the following web site: Diagonals of a Polygon Now you are ready to learn the Polygon Interior Angles Theorem. It involves finding the measure of all of the angles inside a polygon, no matter how big or little ...

Neubert, Mrs.

2011-02-09

155

Angles in the Sky?  

NASA Astrophysics Data System (ADS)

Tycho Brahe lived and worked in the late 1500s before the telescope was invented. He made highly accurate observations of the positions of planets, stars, and comets using large angle-measuring devices of his own design. You can use his techniques to observe the sky as well. For example, the degree, a common unit of measurement in astronomy, can be measured by holding your fist at arm's length up to the sky. Open your fist and observe the distance across the sky covered by the width of your pinky fingernail. That is, roughly, a degree! After some practice, and knowing that one degree equals four minutes, you can measure elapsed time by measuring the angle of the distance that the Moon appears to have moved and multiplying that number by four. You can also figure distances and sizes of things. These are not precise measurements, but rough estimates that can give you a "close-enough" answer.

Behr, Bradford

2005-09-01

156

[Functional disturbances after acute angle closure glaucoma].  

PubMed

This issue presents the results of a study on patients with acute angle closure glaucoma. We analyse the functional disturbances and their long term evolution, and we show some risk factors which lead to severe functional disturbances. PMID:15341106

Macarie, S; Macarie, Daniela

2004-01-01

157

Ejs Brewsterâs Angle Model  

NSDL National Science Digital Library

The Ejs Brewsterâs Angle model displays the electric field of an electromagnetic wave incident on a change of index of refraction. The simulation allows an arbitrarily linearly (in parallel and perpendicular components) polarized wave to encounter the change of index of refraction. The initial electric field and incidence angle change of index of refraction can all be changed via sliders. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Brewsterâs Angle model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_waves_brewster.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-20

158

Perceptions of tilt angles of an agricultural tractor.  

PubMed

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

Görücü, Serap; Cavallo, Eugenio; Murphy, Dennis

2014-01-01

159

Trigger Angle Targeting for Orbital Rendezvous  

NASA Astrophysics Data System (ADS)

Orbital rendezvous missions often have a co-elliptic approach phase where a chaser vehicle approaches an object with a near-constant relative altitude and relative velocity. A well known orbital rendezvous technique is to trigger the Terminal Phase Initiation (TPI) maneuver when the apparent elevation of the target reaches some nominal angle. The best elevation trigger angle on which to initiate the final transfer maneuver must balance favorable performance characteristics and desirable operational simplicity. A detailed analysis is given deriving the best trigger angles and showing how these results correlate to past missions and how they could potentially influence future ones.

Woffinden, David C.; Ben Rose, M.; Geller, David K.

2008-12-01

160

Wide Angle Movie  

NASA Technical Reports Server (NTRS)

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.

1999-01-01

161

Radiometric stability of the Multi-angle Imaging SpectroRadiometer (MISR) following 15 years on-orbit  

NASA Astrophysics Data System (ADS)

The Multi-angle Imaging SpectroRadiometer (MISR) has successfully operated on the EOS/ Terra spacecraft since 1999. It consists of nine cameras pointing from nadir to 70.5° view angle with four spectral channels per camera. Specifications call for a radiometric uncertainty of 3% absolute and 1% relative to the other cameras. To accomplish this, MISR utilizes an on-board calibrator (OBC) to measure camera response changes. Once every two months the two Spectralon panels are deployed to direct solar-light into the cameras. Six photodiode sets measure the illumination level that are compared to MISR raw digital numbers, thus determining the radiometric gain coefficients used in Level 1 data processing. Although panel stability is not required, there has been little detectable change in panel reflectance, attributed to careful preflight handling techniques. The cameras themselves have degraded in radiometric response by 10% since launch, but calibration updates using the detector-based scheme has compensated for these drifts and allowed the radiance products to meet accuracy requirements. Validation using Sahara desert observations show that there has been a drift of ~1% in the reported nadir-view radiance over a decade, common to all spectral bands.

Bruegge, Carol J.; Val, Sebastian; Diner, David J.; Jovanovic, Veljko; Gray, Ellyn; Di Girolamo, Larry; Zhao, Guangyu

2014-09-01

162

Variable angle correlation spectroscopy  

SciTech Connect

In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

Lee, Y.K. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States). Chemical Biodynamics Div.

1994-05-01

163

Triangles: Finding Interior Angle Measures  

NSDL National Science Digital Library

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.

2012-11-25

164

Optical Fibre Angle Sensor Used in MEMS  

NASA Astrophysics Data System (ADS)

There is a need for displacement and angle measurements in many movable MEMS structures. The use of fibre optical sensors helps to measure micrometre displacements and small rotation angles. Advantages of this type of transducers are their simple design, high precision of processing, low costs and ability of a non-contact measurement. The study shows an analysis of a fibre-optic intensity sensor used for MEMS movable structure rotation angle measurement. An intensity of the light in the photodetector is basically dependent on a distance between a reflecting surface and a head surface of the fibre transmitting arm, and the deflection angle. Experimental tests were made for PMMA 980/1000 plastic fibres, ?NA=33°. The study shows both analytical and practical results. It proves that calculated and experimental characteristics for the analysed transducers are similar.

Golebiowski, J.; Milcarz, Sz; Rybak, M.

2014-04-01

165

Heterodyne Interferometer Angle Metrology  

NASA Technical Reports Server (NTRS)

A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

2010-01-01

166

Narrow Angle movie  

NASA Technical Reports Server (NTRS)

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.

1999-01-01

167

Equilibrium contact angle or the most-stable contact angle?  

PubMed

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

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

2014-04-01

168

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

169

Measures on Mixing Angles  

E-print Network

We address the problem of the apparently very small magnitude of CP violation in the standard model, measured by the Jarlskog invariant J. In order to make statements about probabilities for certain values of J, we seek to find a natural measure on the space of Kobayashi-Maskawa matrices, the double quotient U(1)^2\\SU(3)/U(1)^2. We review several possible, geometrically motivated choices of the measure, and compute expectation values for powers of J for these measures. We find that different choices of the measure generically make the observed magnitude of CP violation appear finely tuned. Since the quark masses and the mixing angles are determined by the same set of Yukawa couplings, we then do a second calculation in which we take the known quark mass hierarchy into account. We construct the simplest measure on the space of 3 x 3 Hermitian matrices which reproduces this known hierarchy. Calculating expectation values for powers of J in this second approach, we find that values of J close to the observed val...

Gibbons, Gary W; Pope, C N; Turok, Neil

2008-01-01

170

Cerebellopontine Angle Epidermoids  

PubMed Central

Epidermoids, or congenital cholesteatomas, constitute about 0.2% to 1.5% of intracranial tumors, and 3% to 5% of tumors of the cerebellopontine angle (CPA). We review the surgical management of CPA epidermoids in 13 patients at the House Ear Clinic for the years 1978 to 1993. There were seven male and six female patients, ranging in age from 27 to 59 years (average, 40 years). Tumors ranged in size from 3.5 cm to 7.0 cm, and the surgical approach was tailored to the tumor extent and location. All patients complained at presentation of unilateral hearing loss, and nine had poor speech discrimination (less than 50%) preoperatively. Serviceable hearing was preserved in two patients. Two patients presented with facial nerve symptoms, and four cases had postoperative permanent facial nerve paralysis (House-Brackmann Grade V or VI). There were no surgical deaths. Four patients required second surgeries to remove residual cholesteatoma. Compared with prior series, we describe a higher rate of total tumor removed, as well as a higher rate of second operations, indicating a more aggressive approach to these lesions. ImagesFigure 1Figure 2Figure 3 PMID:17170950

Doyle, Karen Jo; De la Cruz, Antonio

1996-01-01

171

Angle Kappa and its importance in refractive surgery.  

PubMed

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

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

2013-09-01

172

Angle Kappa and its importance in refractive surgery  

PubMed Central

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

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

2013-01-01

173

8.G Find the Angle  

NSDL National Science Digital Library

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...

174

A New Angle on PV Efficiency  

NSDL National Science Digital Library

Students examine how the orientation of a photovoltaic (PV) panel relative to the sun affects the efficiency of the panel. Using sunshine (or a lamp) and a small PV panel connected to a digital multimeter, students vary the angle of the solar panel, record the resulting current output on a worksheet, and plot their experimental results.

Integrated Teaching And Learning Program

175

The Critical Angle Can Override the Brewster Angle  

ERIC Educational Resources Information Center

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.

Froehle, Peter H.

2009-01-01

176

Return of hunger following a relatively high carbohydrate breakfast is associated with earlier recorded glucose peak and nadir  

PubMed Central

Objective To test the hypothesis that a breakfast meal with high carbohydrate/ low fat results in an earlier increase in postprandial glucose and insulin, a greater decrease below baseline in postprandial glucose, and an earlier return of appetite, compared to a low carbohydrate/high fat meal. Design Overweight but otherwise healthy adults (n=64) were maintained on one of two eucaloric diets: high carbohydrate/low fat (HC/LF; 55:27:18% kcals from carbohydrate: fat: protein) versus low carbohydrate/high fat (LC/HF; 43:39:18% kcals from carbohydrate: fat: protein). After 4 weeks of acclimation to the diets, participants underwent a meal test during which circulating glucose and insulin and self-reported hunger and fullness, were measured before and after consumption of breakfast from their assigned diets. Results The LC/HF meal resulted in a later time at the highest and lowest recorded glucose, higher glucose concentrations at 3 and 4 hours post-meal, and lower insulin incremental area under the curve. Participants consuming the LC/HF meal reported lower appetite 3 and 4 hours following the meal, a response that was associated with the timing of the highest and lowest recorded glucose. Conclusions Modest increases in meal carbohydrate content at the expense of fat content may facilitate weight gain over the long-term by contributing to an earlier rise and fall of postprandial glucose concentrations and an earlier return of appetite. PMID:24819342

Chandler-Laney, Paula C.; Morrison, Shannon A.; Goree, Laura Lee T.; Ellis, Amy C.; Casazza, Krista; Desmond, Renee; Gower, Barbara A

2014-01-01

177

Solar cell angle of incidence corrections  

NASA Technical Reports Server (NTRS)

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. The contributed data only went to 65 degrees from normal which prevented any firm conclusions about extreme angle effects although a trend in the right direction was seen. Measurement errors were estimated and found to be consistent with the conclusions that were drawn. A controlled experiment using coverglasses and cells from the same lots and extending to larger incidence angles would probably lead to further insight into the subject area.

Burger, Dale R.; Mueller, Robert L.

1995-01-01

178

Sun Incidence Angle Analysis of KOMPSAT-2 Payload during Normal Mission Operations  

NASA Astrophysics Data System (ADS)

KOMPSAT-2 will carry MSC (Multi-Spectral Camera) which provides 1m resolution panchromatic and 4m resolution multi-spectral images at the altitude of 685km sun-synchronous mission orbit. The mission operation of KOMSPAT-2 is to provide the earth observation using MSC with nadir pointing. KOMPSAT-2 will also have the capability of roll/pitch tilt maneuver using reaction wheel of satellite as required. In order to protect MSC from thermal distortion as well as direct sunlight, MSC shall be operated within the constraint of sun incidence angle. It is expected that the sunlight will not violate the constraint of sun incidence angle for normal mission operations without roll/pitch maneuver. However, during roll/pitch tilt operations, optical module of MSC may be damaged by the sunlight. This study analyzed sun incidence angle of payload using KOMPSAT-2 AOCS (Attitude and Orbit Control Subsystem) Design and Performance Analysis Software for KOMPSAT-2 normal mission operations.

Kim, Eung-Hyun; Yong, Ki-Lyuk; Lee, Sang-Ryool

2000-12-01

179

Study of the advancing and receding contact angles: liquid sorption as a cause of contact angle hysteresis.  

PubMed

Two types of experiments were used to study the behavior of both advancing and receding contact angles, namely the dynamic one-cycle contact angle (DOCA) and the dynamic cycling contact angle (DCCA) experiments. For the preliminary study, DOCA measurements of different liquids on different solids were performed using an automated axisymmetric drop shape analysis-profile (ADSA-P). From these experimental results, four patterns of receding contact angle were observed: (1) time-dependent receding contact angle; (2) constant receding contact angle; (3) 'stick/slip'; (4) no receding contact angle. For the purpose of illustration, results from four different solid surfaces are shown. These solids are: FC-732-coated surface; poly(methyl methacrylate/n-butyl methacrylate) [P(MMA/nBMA)]; poly(lactic acid) (DL-PLA); and poly(lactic/glycolic acid) 50/50 (DL-PLGA 50/50). Since most of the surfaces in our studies exhibit time dependence in the receding contact angle, a more extended study was conducted using only FC-732-coated surfaces to better understand the possible causes of decreasing receding contact angle and contact angle hysteresis. Contact angle measurements of 21 liquids from two homologous series (i.e. n-alkanes and 1-alcohols) and octamethylcyclotetrasiloxane (OCMTS) on FC-732-coated surfaces were performed. It is apparent that the contact angle hysteresis decreases with the chain length of the liquid. It was found that the receding contact angle equals the advancing angle when the alkane molecules are infinitely large. These results strongly suggest that the chain length and size of the liquid molecule could contribute to contact angle hysteresis phenomena. Furthermore, DCCA measurements of six liquids from the two homologous series on FC-732-coated surfaces were performed. With these experimental results, one can construe that the time dependence of contact angle hysteresis on relatively smooth and homogeneous surfaces is mainly caused by liquid retention/sorption. The results also suggested that the contact angle hysteresis will eventually approach a steady state, where the rate of liquid retention-evaporation or sorption process would balance out each other. If the existence of contact angle hysteresis can be attributed to liquid sorption/retention, one should only use the advancing contact angles (measured on a dry surface) in conjunction with Young's equation for surface energetic calculations. PMID:11911113

Lam, C N C; Wu, R; Li, D; Hair, M L; Neumann, A W

2002-02-25

180

Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys and thermal modeling  

E-print Network

The 26 December 2004 Sumatra earthquake (Mw = 9.1) initiated around 30 km depth and ruptured 1300 km of the Indo-Australian Sunda plate boundary. During the Sumatra OBS (ocean bottom seismometer) survey, a wide angle seismic profile was acquired across the epicentral region. A seismic velocity model was obtained from combined travel time tomography and forward modeling. Together with reflection seismic data from the SeaCause II cruise, the deep structure of the source region of the great earthquake is revealed. Four to five kilometers of sediments overlie the oceanic crust at the trench, and the subducting slab can be imaged down to a depth of 35 km. We find a crystalline backstop 120 km from the trench axis, below the fore arc basin. A high velocity zone at the lower landward limit of the raycovered domain, at 22 km depth, marks a shallow continental Moho, 170 km from the trench. The deep structure obtained from the seismic data was used to construct a thermal model of the fore arc in order to predict the li...

Klingelhoefer, Frauke; Ladage, S; Dessa, J -X; Graindorge, David; Franke, D; André, C; Permana, Haryadi; Yudistira, T; Chauhan, Ajay; 10.1029/2009JB006569

2010-01-01

181

Naskah Angling Darma Ambya Madura  

Microsoft Academic Search

ABSTRAK Angling Darma adalah cerita Jawa yang mengisahkan perjalanan seorang raja yang terpaksa meninggalkan kerajaannya sebagai dharma untuk menebus dosa-dosa yang dilakukannya. Angling Darma Ambya Madura ditulis dalam bahasa Madura dialek Sumenep. Oleh kerana proses penulisannya yang diduga melalui teknik penyaduran, versi Madura ini banyak sekali meng- gunakan kata dan ungkapan yang diadaptasi dari bahasa Jawa, sehingga kata dan ungkapan

A. SYUKUR GHAZALI

182

Spinning angle optical calibration apparatus  

DOEpatents

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.

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

1991-01-01

183

The DELPHI small angle tile calorimeter  

Microsoft Academic Search

The small angle tile Calorimeter (STIC) provides calorimetric coverage in the very forward region for the DELPHI experiment at the CERN LEP collider. A veto system composed of two scintillator layers allows one to trigger on single photon events and provides e-? separation. We present here some results of extensive measurements performed on part of the calorimeter and the veto

S. J. Alvsvaag; O. A. Maeland; A. Klovning; A. C. Benvenuti; I. Giordano; M. Guerzoni; F. L. Navarria; M. G. Verardi; T. Camporesi; E. Vallazza; M. Bozzo; R. Cereseto; G. Barreira; M. C. Espirito Santo; A. Maio; A. Onofre; L. Peralta; M. Pimenta; B. Tome; H. Carling; E. Falk; V. Hedberg; G. Jarlskog; I. Kronkvist; M. Bonesini; P. Ferrari; B. Chignoli; S. Gumenyuk; R. Leoni; R. Mazza; P. Negri; L. Paganoni; F. Petrovykh; D. R. Dharmasiri; B. Nossum; A. L. Read; B. Skaali; L. Castellani; M. Pegoraro; A. Fenyuk; Yu. Gouz; Yu. Ivanyushenkov; A. Karyukhin; V. Obraztov; E. Vlasov; A. Zaitsev; M. Bigi; V. Cassio; D. Gamba; E. Migliore; A. Romero; L. Simonetti; E. Torassa; P. P. Trapani; M. Bari; G. Della Ricca; L. Lanceri; P. Poropat; M. Prest

1995-01-01

184

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)

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.

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

2014-12-01

185

Taper Angle Evolution in Taiwan Accretionary Wedge  

NASA Astrophysics Data System (ADS)

Liwen Chena,b, Wu-Cheng Chia, Char-Shine Liuc aInstitute of Earth Sciences, Academia Sinica, Taipei, Taiwan bInstitute of Geosciences, National Taiwan University, Taipei, Taiwan cInstitute of Oceanography, National Taiwan University, Taipei, Taiwan The critical taper model, originally developed using onland Taiwan as an example, is governed by force balance of a horizontal compressional wedge. This model has been successfully applied to many mountainous regions around the world. Among them, Taiwan is located in an oblique collision between the Luzon Arc and the Chinese Passive margin. Previous critical taper angle studies of Taiwan are mainly focusing on utilizing land data. In this study we want to extend these studies to offshore region from the subduction zone to collision zone. Here we study the varying taper angles of the double-vergent wedge derived from 1,000 km of reflection seismic profiles in both the pro-wedge and retro-wedge locations. These profiles were collected in the last two decades. For the retro-wedge, the topography slope angle changes from 2 to 8.8 degrees; some of the steep slope suggests that some part of the retrowedge is currently in a super-critical angle state. Such dramatic changes in taper angle probably strongly affect regional sedimentary processes, including slumping, in addition to structural deformation. These complex processes might even help develop a mélange or re-open a closed basin. We are currently working on studying the taper angle evolution of the pro-wedge from subduction to arc-continent collision zone in the offshore region. Though further works are needed, our preliminary results show that the evolution of wedge angles and the geometry of the wedge are closely linked and inseparable. The structures of the subducting plate might have strong influence on the deformation style of the over-riding plate. It would be interesting to combine the angle variation with the structure interpretation of the accretionary wedge, both in the pro- and retro-wedge regions. And the results might help us to better understand the evolution of Taiwan Accretionary Prism.

Chen, L.; Chi, W.; Liu, C.

2011-12-01

186

Simple multifunctional angle measurement method in orthopaedic  

Microsoft Academic Search

Few types of angle measurementin orthopedic diagnosis process have been studied (Cobb’s Angle, Q-Angle, Bohler’s Angle and Intermetatarsal Angle). A standard and simple multifunctional angle measurement method was identified to help diagnosis and analysis work in orthopedic radiology. Some basic mathematic theorems and equations have been applied to make sure the reliability of the method. The angle measurement method was

Lee Thian Seng; Abdul Yazid Mohd Kassim; Siti Fairuz Yusof; Suhail Abdulah; Shahril Yusof; Hamzaini Abdul Hamid; Riza Sulaiman

2008-01-01

187

Bilateral Q angle asymmetry and anterior knee pain syndrome  

Microsoft Academic Search

Objective. To determine whether quadriceps (Q) angles were bilaterally symmetric in individuals asymptomatic vs symptomatic for anterior knee pain.Design. Cross-sectional study.Background. Previous attempts to link excessive Q angles to the occurrence of knee pain have yielded equivocal results. Deriving unilateral rather than bilateral measures of the Q angle and thereafter analysing data using traditional between-group analysis-of-variance structural models may, however,

Lori A. Livingston; James L. Mandigo

1999-01-01

188

Compact Right-Angle Connector  

NASA Technical Reports Server (NTRS)

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.

Barajas, Salvador L.; Pierson, Vonde E.

1989-01-01

189

Solar Angles and Tracking Systems  

NSDL National Science Digital Library

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.

Integrated Teaching And Learning Program

190

Two Comments on Bond Angles  

NASA Astrophysics Data System (ADS)

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).

Glaister, P.

1997-09-01

191

Comparison of gonial angle determination from cephalograms and orthopantomogram  

PubMed Central

Introduction: Gonial angle is an important parameter of the craniofacial complex giving an indication about the vertical parameters and symmetry of the facial skeleton. Both orthopantomogram (OPG) and lateral cephalograms can be used for the measurement of gonial angle. Because of the superimpositions seen on lateral cephalograms, reliable measurement of the gonial angle becomes difficult. The aim of the present study is to check the possible application and reliability of OPG for gonial angle determination by clarifying whether there is any significant difference between the determination of gonial angle from OPG and cephalogram. Materials and Methods: Gonial angle measurements were made on lateral cephalograms and orthopantomograms of 98 patients - 44 males (mean age 25.9 years) and 54 females (mean age 21.3 years), and compared using Statistical Package for Social Sciences. Results: One-way analysis of variance demonstrated no significant differences between the values of gonial angles determined by lateral cephalogram and panoramic radiography. Pearson correlation showed a high correlation between cephalometric and OPG gonial angle value. Conclusion: Panoramic radiography can be used to determine the gonial angle as accurately as a lateral cephalogram. For determination of the gonial angle, an OPG may be a better choice than a lateral cephalogram as there are no interferences due to superimposed images of anatomical structures as in a lateral cephalogram. Thus, the present study substantiates the possibility of enhancing the clinical versatility of the panoramic radiograph, which is an indispensable tool for dental diagnosis.

Bhullar, Mandeep Kaur; Uppal, Amandeep Singh; Kochhar, Gulsheen Kaur; Chachra, Sanjay; Kochhar, Anuraj Singh

2014-01-01

192

Improved eddy current angle probe  

SciTech Connect

Apparatus is described for detecting flaws in a tubular workpiece in a single scan. The coils of a dual coil bobbin eddy current inspection probe are wound at a 45/sup 0/ angle to the transverse axis of the probe, one coil having an angular position about the axis about 90/sup 0/ relative to the angular position of the other coil, and the angle of intersection of the planes containing the coils being about 60/sup 0/.

Nance, R.A.; Hartley, W.H.; Caffarel, A.J.

1982-02-11

193

Riser unit covers all angles  

SciTech Connect

A riser angle positioning system (RAPS), which measures the angle of selected joints in the riser system and, through the use of a mini-computer develops information on the vessel-wellhead position reference, is described. The system currently is employed on the drillship, Discoverer Seven Seas, which is currently drilling wells in approx. 4000 ft of water. The RAPS provides a backup system for more conventional acoustic systems. Sample calculations are included. (BLM)

Dean, Q.W.

1980-06-05

194

Compression failure of angle-ply laminates  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

195

An Experimental Study on the Iso-Content-Based Angle Similarity Measure.  

ERIC Educational Resources Information Center

Retrieval performance of the iso-content-based angle similarity measure within the angle, distance, conjunction, disjunction, and ellipse retrieval models is compared with retrieval performance of the distance similarity measure and the angle similarity measure. Results show the iso-content-based angle similarity measure achieves satisfactory…

Zhang, Jin; Rasmussen, Edie M.

2002-01-01

196

Study of the advancing and receding contact angles: liquid sorption as a cause of contact angle hysteresis  

Microsoft Academic Search

Two types of experiments were used to study the behavior of both advancing and receding contact angles, namely the dynamic one-cycle contact angle (DOCA) and the dynamic cycling contact angle (DCCA) experiments. For the preliminary study, DOCA measurements of different liquids on different solids were performed using an automated axisymmetric drop shape analysis-profile (ADSA-P). From these experimental results, four patterns

C. N. C Lam; R Wu; D Li; M. L Hair; A. W Neumann

2002-01-01

197

Comparisons of EOS MLS cloud ice measurements with ECMWF analyses and GCM simulations: Initial results  

E-print Network

-tropospheric ice water content (IWC), a new set of IWC measurements from the Earth Observing System's Microwave wavelengths and nadir-viewing geometry. These shortcomings often result in inconsistent definitions between] onboard the Aura satellite (launched on July 15, 2004) has five radio- meters measuring microwave

198

30 CFR 56.19037 - Fleet angles.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 2010-07-01 false Fleet angles. 56.19037 Section 56.19037 Mineral Resources...Hoisting Headframes and Sheaves § 56.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979,...

2010-07-01

199

30 CFR 56.19037 - Fleet angles.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 2011-07-01 false Fleet angles. 56.19037 Section 56.19037 Mineral Resources...Hoisting Headframes and Sheaves § 56.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979,...

2011-07-01

200

30 CFR 57.19037 - Fleet angles.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 2011-07-01 false Fleet angles. 57.19037 Section 57.19037 Mineral Resources...Hoisting Headframes and Sheaves § 57.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979,...

2011-07-01

201

30 CFR 57.19037 - Fleet angles.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 2010-07-01 false Fleet angles. 57.19037 Section 57.19037 Mineral Resources...Hoisting Headframes and Sheaves § 57.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979,...

2010-07-01

202

Incident angle insensitive double negative (DNG) metamaterial absorber  

Microsoft Academic Search

An incident angle insensitive double negative metamaterial absorber by using hexagonal shape is described. It can absorb any incident angle transverse electromagnetic (TEM) wave because of its hexagonal symmetry shape. In spite of its structure, the absorber achieved a 81.5% absorptivity at 10.52 GHz in numerical results.

Youngsoo Jang; Joungyoung Lee; Sungjoon Lim

2011-01-01

203

High angle of attack: Aerodynamics  

NASA Technical Reports Server (NTRS)

The ability to predict high angle of attack, nonlinear, aerodynamic characteristics of flight vehicles, including aircraft, has made significant progress in the last 25 years using computational tools and analyses. The key technological element which has made these analyses possible is the ability to account for the influence of the shed vortical flow, prevalent in this angle of attack range, on geometries of interest. Using selected analysis techniques, applications have also been made to wing design in order to improve their high speed maneuver performance. Various techniques, associated with different levels of accuracy, exist to model this vortical flow influence. The ones included in this paper cover: suction analogy with extensions; free vortex filaments; free vortex sheet modeling; and Euler and Navier-Stokes solutions. Associated relevant features of vortices are also addressed, including: the wing and flow conditions which cause vortex formation; and how the vortex strength varies with angle of attack and wing sweep.

Lamar, John E.

1992-01-01

204

Weak lensing using only galaxy position angles  

NASA Astrophysics Data System (ADS)

We develop a method for performing a weak lensing analysis using only measurements of galaxy position angles. By analysing the statistical properties of the galaxy orientations given a known intrinsic ellipticity distribution, we show that it is possible to obtain estimates of the shear by minimizing a ?2 statistic. The method is demonstrated using simulations where the components of the intrinsic ellipticity are taken to be Gaussian distributed. Uncertainties in the position angle measurements introduce a bias into the shear estimates which can be reduced to negligible levels by introducing a correction term into the formalism. We generalize our approach by developing an algorithm to obtain direct shear estimators given any azimuthally symmetric intrinsic ellipticity distribution. We introduce a method of measuring the position angles of the galaxies from noisy pixelized images, and propose a method to correct for biases which arise due to pixelization and correlations between measurement errors and galaxy ellipticities. We also develop a method to constrain the sample of galaxies used to obtain an estimate of the intrinsic ellipticity distribution such that fractional biases in the resulting shear estimates are below a given threshold value. We demonstrate the angle-only method by applying it to simulations where the ellipticities are taken to follow a lognormal distribution. We compare the performance of the position-angle-only method with the standard method based on full ellipticity measurements by reconstructing lensing convergence maps from both numerical simulations and from the Canada-France-Hawaii Lensing Survey data. We find that the difference between the convergence maps reconstructed using the two methods is consistent with noise.

Whittaker, Lee; Brown, Michael L.; Battye, Richard A.

2014-12-01

205

Recent Flight Results of the TRMM Kalman Filter  

NASA Technical Reports Server (NTRS)

The Tropical Rainfall Measuring Mission (TRMM) spacecraft is a nadir pointing spacecraft that nominally controls the roll and pitch attitude based on the Earth Sensor Assembly (ESA) output. TRMM's nominal orbit altitude was 350 km, until raised to 402 km to prolong mission life. During the boost, the ESA experienced a decreasing signal to noise ratio, until sun interference at 393 km altitude made the ESA data unreliable for attitude determination. At that point, the backup attitude determination algorithm, an extended Kalman filter, was enabled. After the boost finished, TRMM reacquired its nadir-pointing attitude, and continued its mission. This paper will briefly discuss the boost and the decision to turn on the backup attitude determination algorithm. A description of the extended Kalman filter algorithm will be given. In addition, flight results from analyzing attitude data and the results of software changes made onboard TRMM will be discussed. Some lessons learned are presented.

Andrews, Stephen F.; Bilanow, Stephen; Bauer, Frank (Technical Monitor)

2002-01-01

206

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)

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.

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

2013-07-01

207

Discovering the Inscribed Angle Theorem  

ERIC Educational Resources Information Center

Learning to play tennis is difficult. It takes practice, but it also helps to have a coach--someone who gives tips and pointers but allows the freedom to play the game on one's own. Learning to act like a mathematician is a similar process. Students report that the process of proving the inscribed angle theorem is challenging and, at times,…

Roscoe, Matt B.

2012-01-01

208

Ring magnet firing angle control  

Microsoft Academic Search

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

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

1975-01-01

209

Tilt angle control of nanocolumns grown by glancing angle sputtering at variable argon pressures  

SciTech Connect

We show that the tilt angle of nanostructures obtained by glancing angle sputtering is finely tuned by selecting the adequate argon pressure. At low pressures, a ballistic deposition regime dominates, yielding high directional atoms that form tilted nanocolumns. High pressures lead to a diffusive regime which gives rise to vertical columnar growth. Monte Carlo simulations reproduce the experimental results indicating that the loss of directionality of the sputtered particles in the gas phase, together with the self-shadowing mechanism at the surface, are the main processes responsible for the development of the columns.

Garcia-Martin, J. M.; Cebollada, A. [IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid (Spain); Alvarez, R.; Romero-Gomez, P.; Palmero, A. [Instituto de Ciencia de Materiales de Sevilla, (CSIC-Universidad de Sevilla), Americo Vespucio 49, 41092 Seville (Spain)

2010-10-25

210

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

PubMed

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

McCabe, Patrick; Korb, Oliver; Cole, Jason

2014-05-27

211

ADNL-Angle: Accurate Distributed Node Localization for Wireless Sensor Networks with Angle of Arrival Information  

NASA Astrophysics Data System (ADS)

This paper deals with the collaborative multi-hop localization problem in static Wireless Sensor Networks with Angle of Arrival information. We present ADNL-Angle, a new, original and efficient localization algorithm. Our method uses a small set of sensors which know their positions, it also uses the 2-hop neighborhood knowledge and angular information between neighbor nodes computed thanks to AoA technology. Each node with enough anchors in its neighborhood locally runs a kind of force-based algorithm so as to localize itself, and then forward its position to enable other nodes to locate themselves. We also propose an additional delaying mechanism to increase localization accuracy. We provide extensive simulation results showing the accuracy and the robustness of ADNL-Angle even with noisy angular measurements, few anchor nodes and realistic topologies.

Champ, Julien; Boudet, Vincent

212

Brook Trout Angling in Maine 2009 Survey Results  

E-print Network

this fishery. In response to this, the group identified a need for current research to identify the brook trout of Maine Cooperative Extension developed an on-line survey of resident and non-resident anglers who stakeholders, as supported by this research. This information is intended to provide research based information

Thomas, Andrew

213

Arbitrary angle waveguide bends based on zero-index metamaterials  

NASA Astrophysics Data System (ADS)

In this paper, efficient arbitrary angle bends based on impedance-matched zero-index metamaterials (ZIMs) are proposed. Numerical simulations on ZIM-based bends are carried out in waveguide systems. The results show clearly that electromagnetic waves can tunnel through the ZIM-based bends with high transmittance at any bending angles. Moreover, a realistic ZIM-based bends are designed and fabricated on microstrip transmission line. Both simulated and experimental results confirm well the low loss and arbitrary angle bending effects in a system hiring ZIM-based microstrip ring resonator as bending corners.

Li, Y. H.; Zhang, L. H.; Chen, Y. Q.; Feng, T. H.; Jiang, H. T.; Chen, H.

2014-08-01

214

Gaia basic angle monitoring system  

NASA Astrophysics Data System (ADS)

The Gaia mission1 will create an extraordinarily precise three-dimensional map of more than one billion stars in our Galaxy. The Gaia spacecraft2, built by EADS Astrium, is part of ESA's Cosmic Vision programme and scheduled for launch in 2013. Gaia measures the position, distance and motion of stars with an accuracy of 24 micro-arcsec using two telescopes at a fixed mutual angle of 106.5°, named the `Basic Angle', at an operational temperature of 100 K. This accuracy requires ultra-high stability at cryogenic conditions, which can only be achieved by using Silicon Carbide for both the optical bench and the telescopes. TNO has developed, built and space qualified the Silicon carbide Basic Angle Monitoring (BAM) on-board metrology system3 for this mission, measuring the relative motion of Gaia's telescopes with accuracies in the range of 0.5 micro-arcsec. This is achieved by a system of two laser interferometers able to detect Optical Path Differences (OPD) as small as 1.5 picometer rms. Following a general introduction on Gaia and the use of Silicon Carbide as base material this paper addresses the specific challenges towards the cryogenic application of the Gaia BAM including design, integration and verification/qualification by testing.

Gielesen, W.; de Bruijn, D.; van den Dool, T.; Kamphues, F.; Mekking, J.; Calvel, B.; Laborie, A.; Coatantiec, C.; Touzeau, S.; Erdmann, M.; Gare, P.; Monteiro, D.

2013-09-01

215

OPENING ANGLES OF COLLAPSAR JETS  

SciTech Connect

We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by ?{sub j} ? 1/5?{sub 0} and infer the initial Lorentz factor of the jet at the central engine, ?{sub 0}, is a few for existing observations of ?{sub j}. The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this new picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle ?{sub j,{sub max}} ? 1/5 ? 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.

Mizuta, Akira; Ioka, Kunihito [Theory Center, Institute of Particle and Nuclear Studies, KEK, Tsukuba 305-0801 (Japan)

2013-11-10

216

Opening Angles of Collapsar Jets  

NASA Astrophysics Data System (ADS)

We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by ? j ~ 1/5?0 and infer the initial Lorentz factor of the jet at the central engine, ?0, is a few for existing observations of ? j . The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this new picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle ? j, max ~ 1/5 ~ 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.

Mizuta, Akira; Ioka, Kunihito

2013-11-01

217

The hypotensive effect of selective laser trabeculoplasty depending on iridocorneal angle pigmentation in primary open angle glaucoma patients  

PubMed Central

Introduction Selective laser trabeculoplasty (SLT) is applied to reduce intraocular pressure in primary open angle glaucoma therapy. It selectively subjects trabecular pigmented cells to a pulsed, frequency-doubled Nd:YAG laser. The biostimulatory effect on trabecular macrophages was also postulated even in low-pigmented angles. The aim of the study was to assess the hypotensive effectiveness of SLT depending on the degree of iridocorneal angle pigmentation. Material and methods Sixty-three eyes of 53 patients with primary open angle glaucoma (POAG) were included in this study and than divided into three subgroups, dependind of iridocorneal angle pigmentation. All subjects underwent SLT on 270 degrees of the angle. Intraocular pressure (IOP) was assesed at baseline and 6 weeks after the laser procedure. Results Six weeks post-SLT mean IOP reduction was 2.63 mm Hg. The degree of IOP reduction showed a significant correlation with angle pigmentation. Intraocular pressure fell by 2.06 mm Hg, 2.46 mm Hg and 4.75 mm Hg in subgroups with low, marked and high pigmentation, respectively. Conclusions The SLT procedure most effectively reduces IOP only in the subgroup of POAG patients with marked angle pigmentation and it is equal to clinically succesfull hypontesive therapeutic effect, according to European Glaucoma Society guidelines. However, lower hypotensive effect in other study subjects may also be the valuable addition to pharmacological therapy of glaucoma. PMID:24904665

Piekarniak-Wozniak, Anita; Grabska-Liberek, Iwona

2014-01-01

218

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

E-print Network

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 ...

Nowak, Sara Alice, 1982-

2004-01-01

219

X-29 at High Angle of Attack  

NASA Technical Reports Server (NTRS)

This photo shows the X-29 during a 1991 research flight. Smoke generators in the nose of the aircraft were used to help researchers see the behavior of the air flowing over the aircraft. The smoke here is demonstrating forebody vortex flow at a high angle of attack. Angle of attack, or high alpha, refers to the angle of an aircraft's body and wings relative to its actual flight path.. The tufts that can be seen in this photo attached to the fuselage and wings of the X-29 were also used to help researchers visualize the air flow over the plane. Two X-29 aircraft, featuring one of the most unusual designs in aviation history, flew at the Ames-Dryden Flight Research Facility (now the Dryden Flight Research Center, Edwards, California) from 1984 to 1992. The fighter-sized X-29 technology demonstrators explored several concepts and technologies including: the use of advanced composites in aircraft construction; variable-camber wing surfaces; a unique forward- swept wing and its thin supercritical airfoil; strakes; close-coupled canards; and a computerized fly-by-wire flight control system used to maintain control of the otherwise unstable aircraft. Research results showed that the configuration of forward-swept wings, coupled with movable canards, gave pilots excellent control response at angles of attack of up to 45 degrees. During its flight history, the X-29 aircraft flew 422 research missions and a total of 436 missions. Sixty of the research flights were part of the X-29 follow-on 'vortex control' phase. The forward-swept wing of the X-29 resulted in reverse airflow, toward the fuselage rather than away from it, as occurs on the usual aft-swept wing. Consequently, on the forward-swept wing, the ailerons remained unstalled at high angles of attack. This provided better airflow over the ailerons and prevented stalling (loss of lift) at high angles of attack. Introduction of composite materials in the 1970s opened a new field of aircraft construction. It also made possible the construction of the X-29's thin supercritical wing. State-of-the-art composites allowed aeroelastic tailoring which, in turn, allowed the wing some bending but limited twisting and eliminated structural divergence within the flight envelope (i.e. deformation of the wing or the wing breaking off in flight). Additionally, composite materials allowed the wing to be sufficiently rigid for safe flight without adding an unacceptable weight penalty. The X-29 project consisted of two phases plus the follow-on vortex-control phase. Phase 1 demonstrated that the forward sweep of the X-29 wings kept the wing tips unstalled at the moderate angles of attack flown in that phase (a maximum of 21 degrees). Phase I also demonstrated that the aeroelastic tailored wing prevented structural divergence of the wing within the flight envelope, and that the control laws and control-surface effectiveness were adequate to provide artificial stability for an otherwise unstable aircraft. Phase 1 further demonstrated that the X-29 configuration could fly safely and reliably, even in tight turns. During Phase 2 of the project, the X-29, flying at an angle of attack of up to 67 degrees, demonstrated much better control and maneuvering qualities than computational methods and simulation models had predicted . During 120 research flights in this phase, NASA, Air Force, and Grumman project pilots reported the X-29 aircraft had excellent control response to an angle of attack of 45 degrees and still had limited controllability at a 67-degree angle of attack. This controllability at high angles of attack can be attributed to the aircraft's unique forward-swept wing- canard design. The NASA/Air Force-designed high-gain flight control laws also contributed to the good flying qualities. During the Air Force-initiated vortex-control phase, the X-29 successfully demonstrated vortex flow control (VFC). This VFC was more effective than expected in generating yaw forces, especially in high angles of attack where the rudder is less effective. VFC was less effective in providing control when side

1991-01-01

220

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

PubMed Central

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

Linthorne, Nicholas P.; Patel, Dipesh S.

2011-01-01

221

Distributions of Angles in Random Packing on Spheres  

PubMed Central

This paper studies the asymptotic behaviors of the pairwise angles among n randomly and uniformly distributed unit vectors in Rp as the number of points n ? ?, while the dimension p is either fixed or growing with n. For both settings, we derive the limiting empirical distribution of the random angles and the limiting distributions of the extreme angles. The results reveal interesting differences in the two settings and provide a precise characterization of the folklore that “all high-dimensional random vectors are almost always nearly orthogonal to each other”. Applications to statistics and machine learning and connections with some open problems in physics and mathematics are also discussed.

Cai, Tony; Fan, Jianqing; Jiang, Tiefeng

2014-01-01

222

Wall Angle Effects on Nozzle Separation Stability  

NASA Astrophysics Data System (ADS)

The presence of asymmetric side loads due to unstable separation within over-expanded rocket nozzles is well documented. Although progress has been made in developing understanding of this phenomenon through numerical and experimental means, the causes of these side loads have yet to be fully explained. The hypothesis examined within this paper is that there is a relationship between nozzle wall angle at the point of separation, and the stability of the flow separation. This was achieved through an experimental investigation of a series of subscale over-expanded conical nozzles with half-angles of 8.3°, 10.4°, 12.6° and 14.8°. All had overall area ratios of 16:1, with separation occurring at approximately half the nozzle length (i.e. area ration of 4:1) under an overall pressure ratio of approximately 7:1 using air as the working fluid. The structure of exhaust flow was observed and analysed by use of an optimised Schlieren visualisation system, coupled with a high speed digital camera. The 12.6° and 14.8° nozzles exhaust flow were seen to be stable throughout the recorded test period of 10 seconds. However, a small number of large fluctuations in the jet angle were seen to be present within the flowfield of the 10.4° nozzle, occurring at apparently random intervals through the test period. The flowfield of the 8.3° nozzle demonstrated near continuous, large angle deviations in the jet, with flow patterns containing thickened shear layers and apparent reattachment to the wall, something not previously identified in conical nozzles. These results were used to design a truncated ideal contour with an exit angle of over 10 degrees, in order to assess the possibility of designing conventional nozzles that separate stably over a wide range of pressure ratios. These tests were successful, potentially providing a simpler, cheaper alternative to altitude compensating nozzle devices. However, more work determining the nature of the separation and its causes is required.

Aghababaie, A.; Taylor, N.

223

Calculating Angle Lambda (?) Using Zernike Tilt Measurements in Specular Reflection Corneal Topography  

PubMed Central

Purpose To develop a method to calculate the angle ? of the human eye using Zernike tilt measurements in specular reflection corneal topography. Methods The meaning of Zernike tilt in specular reflection corneal topography is demonstrated by measurements on translated artificial surfaces using the VU Topographer. The relationship derived from the translation experiments is used to determine the angle ?. Corneal surfaces are measured for a set of eight different fixation points, for which tilt angles ? are obtained from the Zernike tilt coefficients. The angles ? are used with respect to the fixation target angles to determine angle ? by fitting a geometrical model. This method is validated with Orbscan II's angle-? measurements in 9 eyes. Results The translation experiments show that the Zernike tilt coefficient is directly related to an angle ?, which describes a tilt orientation of the cornea and can therefore be used to derive a value for angle ?. A significant correlation exists between measured values for angle ? with the VU Topographer and the angle ? with the Orbscan II (r=0.95, P<0.001). A Bland-Altman plot indicates a mean difference of -0.52 degrees between the two instruments, but this is not statistically significant as indicated by a matched-pairs Wilcoxon signed-rank test (P?0.1748). The mean precision for measuring angle ? using the VU topographer is 0.6±0.3 degrees. Conclusion The method described above to determine angle ? is sufficiently repeatable and performs similarly to the angle-? measurements made with the Orbscan II.

Braaf, Boy; van de Watering, Thomas Christiaan; Spruijt, Kees; van der Heijde, Rob G.L.; Sicam, Victor Arni D.P.

2010-01-01

224

Airfoil Shaped Flow Angle Probe  

NASA Technical Reports Server (NTRS)

The present invention is a force-based instrument that measures local flow angle. The preferred embodiment of the invention has a low aspect ratio airfoil member connected to a mounting base. Using a series of strain gauges located at the connecting portion of the probe, aerodynamic forces on the airfoil member can be converted to strain, which in turn can be converted to local air flow measurements. The present invention has no moving parts and is well suited for measuring flow in a transonic and supersonic regime.

Corda, Stephen (Inventor); Vachon, Michael Jake (Inventor)

2003-01-01

225

Integrated Study of APS YSZ Coatings with Different Spray Angle  

NASA Astrophysics Data System (ADS)

Spray parameters play an important role on the microstructure and properties of plasma-sprayed coatings. Parameters such as spray distance, plasma gas flow and current, raster speed, and spray angle all can be varied. In this paper, an integrated study to investigate the effects and influences of spray angle on properties of yttria-stabilized zirconia coatings was carried out with spray angles of 60°, 75°, and 90° (to the substrate surface). In situ coating property sensor based on beam curvature measurements was used to measure the evolving stress and elastic moduli of the resultant coatings and combined with other characterization tools for thermo-physical property and microstructure analysis, such as laser flash and scanning electron microscopy. The results indicate that the coating with 60° spray angle had the lowest thermal conductivity and more compliant structure. This study seeks to understand the mechanism for this effect and will provide important insight into parametric sensitivities on complex spray parts.

Chen, Yikai; Tan, Yang; Tessarini, Silvia; Sampath, Sanjay

2013-03-01

226

The use of liquid jets to simulate angled drop impact  

NASA Astrophysics Data System (ADS)

The liquid jet impact technique has been used extensively for the quantitative study of rain impact. Most of this work has been for normal impact. Although some angled impact studies have been pursued using jets, these have been purely of a qualitative nature. This paper develops the theory of angled drop impact. This allows the establishment of a method of correlating between angled drop and jet impact and obtaining ``equivalent drop'' curves for jet impact. The correlation is also applied to normal impact. For normal impact it is shown that the previously published equivalent drop curves need to be modified especially at low velocities. The results for both normal and angled impact are discussed with reference to the details of the jet profile, and it is shown that angled jets may be considered as having an average equivalent drop size. The theory of angled impact also explains the shape of damage marks produced by impact and why the amount of damage decreases so rapidly with increasing angle.

Hand, R. J.; Field, J. E.; Townsend, D.

1991-12-01

227

Analysis of Ku-band cross section at low incidence angles  

NASA Technical Reports Server (NTRS)

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.

Chapron, B.; Vandemark, D.

1993-01-01

228

Numerical Study on Flow Angles and Mach Number Measurement Using the Surface Pressure of a Supersonic Aircraft with Nosecone  

Microsoft Academic Search

Numerical simulation on the Air Data Sensor System (ADS), which measures the flow angles and Mach number using the surface pressures on a nose cone, was conducted in this study. The effect of the half cone angle on the flow angle and Mach number measurement was investigated. As a result, we found that a large half cone angle achieves a

2010-01-01

229

Angle of arrival and irradiance statistics of laser beams in turbulence  

Microsoft Academic Search

Measurement of the local angle of arrival in a laser beam traveling in turbulence is achieved by frequency demodulating the heterodyne signal derived from the interference of a probe and a reference beam. The resulting data are then used to demonstrate that the statistical correlation between the angle of arrival and the irradiance is weak and that the random angle

L. Bissonnette; R. Cote

1981-01-01

230

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

PubMed

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

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

2012-06-01

231

The driven pendulum at arbitrary drive angles  

NASA Astrophysics Data System (ADS)

We discuss the equation of motion of the driven pendulum and generalize it to arbitrary driving angle. The pendulum will oscillate about a stable angle other than straight down if the drive amplitude and frequency are large enough for a given drive angle. The emphasis is on the parameters associated with a simply made demonstration apparatus.

VanDalen, Gordon J.

2004-04-01

232

Final report on CCL-K3: Calibration of angle standards  

Microsoft Academic Search

This report is prepared by the Discussion Group 3 (DG3) for angle standards under the CCL Working Group on Dimensional Metrology (WGDM). It describes the results of Key Comparison CCL-K3 concerning measurements of a chrome carbide twelve-sided optical polygon with nominal angles of 30° and four angle blocks with nominal angles of 5 arc seconds, 5 minutes, 30 minutes and

O A Kruger

2009-01-01

233

KEY COMPARISON: Final report on CCL-K3: Calibration of angle standards  

Microsoft Academic Search

This report is prepared by the Discussion Group 3 (DG3) for angle standards under the CCL Working Group on Dimensional Metrology (WGDM). It describes the results of Key Comparison CCL-K3 concerning measurements of a chrome carbide twelve-sided optical polygon with nominal angles of 30° and four angle blocks with nominal angles of 5 arc seconds, 5 minutes, 30 minutes and

O. A. Kruger

2009-01-01

234

Aerodynamics characteristic of UiTM's BWB UAV Baseline-II at different canard deflection angles at low pitching angle  

Microsoft Academic Search

This paper discusses the influence of canard deflection angle on the aerodynamics characteristic of a Blended Wing Body (BWB) Baseline-II aircraft obtained from wind tunnel test. Canard is added as longitudinal control. All tests are carried out in UiTM Low Speed Wind Tunnel using 1\\/6 scaled model at around 0.1 Mach number at several canard angle. The result of the

Nor Fazira Reduan; Wirachman Wisnoe; Wahyu Kuntjoro; Rizal Effendy Mohd Nasir; Firdaus Mohamad; Zurriati Ali

2010-01-01

235

Differences in peak knee valgus angles between individuals with high and low Q-angles during a single limb squat  

Microsoft Academic Search

Background. Differences in anatomical alignment between genders have been suggested as causes of the disparity in anterior cruciate ligament injury rates. A larger Q-angle may be associated with increased knee valgus during movement resulting in anterior cruciate ligament strain. This study investigated whether healthy college-aged subjects with a large Q-angle display greater peak knee valgus during a single limb squat

Kathleen J. Pantano; Scott C. White; Louise A. Gilchrist; John Leddy

2005-01-01

236

ILC Extraction Line for 14 mrad Crossing Angle  

SciTech Connect

The earlier studies of the ILC extraction line for 20 mrad and 2 mrad crossing angle options [1]-[5] showed that the 20 mrad design has an advantage of a simpler beamline and lower extraction beam loss because of the independent incoming and extraction optics. However, the large 20 mrad crossing angle requires the use of a crab cavity correction, increases synchrotron radiation emittance growth in the solenoid, and increases photon backscattering from the forward calorimeter of the detector. To reduce these effects, an attempt has been made to minimize the crossing angle while keeping the extraction and incoming lines separate. A new quadrupole scheme near the interaction point has been proposed which allows a reduction of the crossing angle to 14 mrad [6]. The optics design and results of tracking and background simulations for the 14 mrad extraction line are presented.

Nosochkov, Y.; Markiewicz, T.; Maruyama, T.; Seryi, A.; /SLAC; Parker, B.; /Brookhaven

2005-12-08

237

Incident beam effects in angle-resolved Auger electron spectroscopy  

NASA Astrophysics Data System (ADS)

We have investigated the role of the angle of electron beam incidence in producing anisotropies in angle-resolved Auger electron emission from single crystals. By performing angle-dependent measurements of Pd MNN Auger emission from Pd(001) with two different angles of incidence, we show that the Auger electron angular distributions are independent of incident beam direction. Rather, the observed intensity modulation is the result of Auger electron scattering and interference, as demonstrated by the comparison of experimental angular distributions with those calculated using kinematical scattering theory. In the calculation, it is assumed that atoms in each layer below the surface receive equal incident beam flux for all angular orientations (i.e., no incident beam channeling). Agreement between theory and experiment is good, indicating that although incident beam channeling surely occurs, the enhanced depth of penetration is ineffective at producing Auger electrons which can reach the surface without suffering inelastic scattering.

Chambers, S. A.; Chen, H. W.; Anderson, S. B.; Weaver, J. H.

1986-09-01

238

Mirror, Mirror on the Wall: Angles of Reflection  

NSDL National Science Digital Library

In this activity, students mount a covered mirror on a wall at eye level, then work in pairs to predict where two people must stand so each can see the other's reflection in the mirror. Each pair will discuss and agree on the places where they think they must stand, then remove the cover from the mirror and test their predictions. As an extension of this activity, they can design and construct large protractors out of cardboard to measure their angles of incidence and reflection and draw and record their results in their science notebooks. Each team of students should be able to explain to another group how they constructed the protractors and how they used them to measure the angles. A link is provided to an interactive Java tutorial on angles of reflection where students can explore how light reflects off a mirror at different angles.

239

High-dynamic angle measurement based on laser displacement sensors.  

PubMed

It is currently difficult to achieve good real-time dynamic angle measurements with high accuracy and large ranges. In this paper, a photoelectric measurement method for dynamic angles based on three laser displacement sensors (LDSs) is proposed. Offline, a dynamic angle vision measurement model is established, and the system is calibrated by using a planar target moved by a 2D moving platform. In the course of measurement, three laser beams emitted from three LDSs are projected onto a rotating plane, and three noncollinear points are acquired synchronously; then the rotation angle is calculated in real time. Simulations verify the feasibility of the method theoretically. Experimental results demonstrate that the method achieves measurement accuracies of 0.008° and 0.046° under quasi-static condition of 80°/s and highly dynamic condition of 1000°/s within the measurement range of about ±40°, respectively. PMID:23938418

Sun, Junhua; Zhang, Jie; Liu, Zhen; Zhang, Guangjun

2013-08-10

240

Contact angles of liquid metals on quasicrystals  

NASA Astrophysics Data System (ADS)

Wetting with µm-sized Pb droplets on thin polycrystalline films of decagonal Al13Co4 is reported. The films were prepared under high vacuum conditions in order to have Pb droplets lying on a clean surface. The method used is sequential deposition and annealing of specific stackings of Al and Co layers of nanometric thicknesses. A 300 nm thick Pb slab was then deposited on top of the films and dewetting experiments were followed in situ in a scanning Auger microprobe. The contact angle between the Pb droplet and the surface of the film is measured to be 49° ± 7°. Further investigation performed by cross section transmission electron microscopy allows us to better characterize the interface. Taking into account the rugosity of the film, it is concluded that there is partial wetting of the film, which corresponds to a smaller contact angle. The comparison with other results obtained either with pure metals or with a cubic AlCo compound leads to the conclusion that the wetting behaviour of Pb on the surface of a decagonal compound is close to that of a metal with a high melting point and not significantly different from that of a crystalline compound with a small unit cell.

Bergman, Claire; Girardeaux, Christophe; Perrin-Pellegrino, Carine; Gas, Patrick; Dubois, Jean-Marie; Rivier, Nicolas

2008-08-01

241

Anomalous and resonance small angle scattering: Revision  

SciTech Connect

Significant changes in the small angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous dispersion terms for the scattering factor (x-rays) or scattering length (neutrons). The physics inherent in these anomalous dispersion terms is first discussed before considering how they enter the relevant scattering theory. Two major areas of anomalous scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with x-rays. However, it is pointed out that the formalism is the same for the analogue experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small angle neutron scatterings are discussed. 54 refs., 8 figs., 1 tab.

Epperson, J.E.; Thiyagarajan, P.

1987-11-01

242

Limbus Impact on Off-angle Iris Degradation  

SciTech Connect

The accuracy of iris recognition depends on the quality of data capture and is negatively affected by several factors such as angle, occlusion, and dilation. Off-angle iris recognition is a new research focus in biometrics that tries to address several issues including corneal refraction, complex 3D iris texture, and blur. In this paper, we present an additional significant challenge that degrades the performance of the off-angle iris recognition systems, called the limbus effect . The limbus is the region at the border of the cornea where the cornea joins the sclera. The limbus is a semitransparent tissue that occludes a side portion of the iris plane. The amount of occluded iris texture on the side nearest the camera increases as the image acquisition angle increases. Without considering the role of the limbus effect, it is difficult to design an accurate off-angle iris recognition system. To the best of our knowledge, this is the first work that investigates the limbus effect in detail from a biometrics perspective. Based on results from real images and simulated experiments with real iris texture, the limbus effect increases the hamming distance score between frontal and off-angle iris images ranging from 0.05 to 0.2 depending upon the limbus height.

Karakaya, Mahmut [ORNL; Barstow, Del R [ORNL; Santos-Villalobos, Hector J [ORNL; Thompson, Joseph W [ORNL; Bolme, David S [ORNL; Boehnen, Chris Bensing [ORNL

2013-01-01

243

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

NASA Technical Reports Server (NTRS)

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.

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

244

Disulfide Bond Dihedral Angles from Raman Spectroscopy  

PubMed Central

Raman spectra of several compounds containing the CS-SC moiety were obtained (in the solid phase) from 450-800 cm-1 to investigate the S-S and C-S stretching behavior. The S-S stretching frequency varied linearly with the CS-SC dihedral angle (obtained from either x-ray or neutron diffraction or ultraviolet absorption) for compounds whose CC-SS dihedral angles were not very different. The ratio of the intensities of the S-S and C-S stretching bands exhibited no recognizable correlation with either the CS-SC dihedral angle or the CSS bond angle, probably because this ratio is sensitive to the crystalline environment. The linear dependence of the S-S stretching frequency on dihedral angle leads to a dihedral angle for the plant hormone, malformin A, that is in excellent agreement with that estimated from the longest wavelength CS-SC ultraviolet absorption band. PMID:16592108

Van Wart, Harold E.; Lewis, Aaron; Scheraga, Harold A.; Saeva, Frank D.

1973-01-01

245

Luminosity of angled collision of strongly focused beams with different Gaussian distributions  

NASA Astrophysics Data System (ADS)

The geometric luminosity of angled collision of strongly focused beams with different Gaussian distributions or asymmetric beams is discussed generally on the basis of pseudo-isotropic beam model. The discussion is simplified by converting the angled collision to the head-on collision in a moving frame. There is a transition angle of collision, above which the hourglass effect becomes less effective. The resultant reduction factor of luminosity can be applied to any case of angled collision of asymmetric beams. Numerical examples are given on the angled collision of laser and electron beams for ?-ray generation, and on the electron and positron beam collision in storage rings.

Miyahara, Yoshikazu

2008-04-01

246

A ciliary body tumor preventing angle closure.  

PubMed

We present a case report of a 60-year-old white woman, found to have advanced angle closure glaucoma in the right eye and appositional closure for about half of the left eye and no glaucoma. The remaining angle of the left eye was open with localized heavy pigmentation of the ciliary body band and trabecular meshwork. Ultrasound biomicroscopy showed a ciliary body tumor displacing the iris root centripetally preventing angle closure. PMID:23117627

Mehanna, Chadi; Desjardins, Laurence; Puech, Michel; Cohn, Howard

2014-02-01

247

A model of electrowetting, reversed electrowetting, and contact angle saturation.  

PubMed

While electrowetting has many applications, it is limited at large voltages by contact angle saturation, a phenomenon that is still not well understood. We propose a generalized approach for electrowetting that, among other results, can shed new light on contact angle saturation. The model assumes the existence of a minimum (with respect to the contact angle) in the electric energy and accounts for a quadratic voltage dependence ?U(2) in the low-voltage limit, compatible with the Young-Lippmann formula, and an ?U(-2) saturation at the high-voltage limit. Another prediction is the surprising possibility of a reversed electrowetting regime, in which the contact angle increases with applied voltage. By explicitly taking into account the effect of the counter-electrode, our model is shown to be applicable to several AC and DC experimental electrowetting-on-dielectric (EWOD) setups. Several features seen in experiments compare favorably with our results. Furthermore, the AC frequency dependence of EWOD agrees quantitatively with our predictions. Our numerical results are complemented with simple analytical expressions for the saturation angle in two practical limits. PMID:21510663

Klarman, Dan; Andelman, David; Urbakh, Michael

2011-05-17

248

Analyzing angle crashes at unsignalized intersections using machine learning techniques.  

PubMed

A recently developed machine learning technique, multivariate adaptive regression splines (MARS), is introduced in this study to predict vehicles' angle crashes. MARS has a promising prediction power, and does not suffer from interpretation complexity. Negative Binomial (NB) and MARS models were fitted and compared using extensive data collected on unsignalized intersections in Florida. Two models were estimated for angle crash frequency at 3- and 4-legged unsignalized intersections. Treating crash frequency as a continuous response variable for fitting a MARS model was also examined by considering the natural logarithm of the crash frequency. Finally, combining MARS with another machine learning technique (random forest) was explored and discussed. The fitted NB angle crash models showed several significant factors that contribute to angle crash occurrence at unsignalized intersections such as, traffic volume on the major road, the upstream distance to the nearest signalized intersection, the distance between successive unsignalized intersections, median type on the major approach, percentage of trucks on the major approach, size of the intersection and the geographic location within the state. Based on the mean square prediction error (MSPE) assessment criterion, MARS outperformed the corresponding NB models. Also, using MARS for predicting continuous response variables yielded more favorable results than predicting discrete response variables. The generated MARS models showed the most promising results after screening the covariates using random forest. Based on the results of this study, MARS is recommended as an efficient technique for predicting crashes at unsignalized intersections (angle crashes in this study). PMID:21094345

Abdel-Aty, Mohamed; Haleem, Kirolos

2011-01-01

249

8.G Find the Missing Angle  

NSDL National Science Digital Library

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 the picture below, lines $l$ and $m$ are parallel. The measure of angle $\\angle PAX$ is $31^\\circ$, and the measure of angle $\\angle PBY$ is $54^\\ci...

250

Pitch Angle of Galactic Spiral Arms  

NASA Astrophysics Data System (ADS)

One of the key parameters that characterizes spiral arms in disk galaxies is a pitch angle that measures the inclination of a spiral arm to the direction of galactic rotation. The pitch angle differs from galaxy to galaxy, which suggests that the rotation law of galactic disks determines it. In order to investigate the relation between the pitch angle of spiral arms and the shear rate of galactic differential rotation, we perform local N-body simulations of pure stellar disks. We find that the pitch angle increases with the epicycle frequency and decreases with the shear rate and obtain the fitting formula. This dependence is explained by the swing amplification mechanism.

Michikoshi, Shugo; Kokubo, Eiichiro

2014-06-01

251

Roughness effects on contact angle measurements  

NASA Astrophysics Data System (ADS)

We have developed a simple and economical procedure to demonstrate the effects of roughness and wetting fraction on the equilibrium contact angles of liquid droplets on solid surfaces. Contact angles for droplets placed on a rough surface, which wet only a portion of the surface, are larger than the contact angles of droplets formed by condensation of steam, which wet the surface more completely. These contact angle data facilitate assessments of changes in true surface area, due to surface roughening, as well as changes in the fractional contact areas of the water droplets, due to the formation of air pockets between the rough surface and the droplet.

Ryan, Bernard J.; Poduska, Kristin M.

2008-11-01

252

Biomechanical Analysis of Differing Pedicle Screw Insertion Angles  

PubMed Central

Background Pedicle screw fixation to stabilize lumbar spinal fusion has become the gold standard for posterior stabilization. A significant percentage of surgical candidates are classified as obese or morbidly obese. For these patients, the depth of the incisions and soft tissue makes it extremely difficult to insert pedicle screws along the pedicle axis. As such, the pedicle screws could only be inserted in a much more sagittal axis. However, biomechanical stability of the angled screw insertion has been controversial. We hypothesized that the straight or parallel screw was a more stable construct compared to the angled or axially inserted screw when subjected to caudal cyclic loading. Methods We obtained 12 fresh frozen lumbar vertebrae from L3 to L5 from five cadavers. Schantz screws (6.0mm) were inserted into each pedicle, one angled and along the axis of the pedicle and the other parallel to the spinous process. Fluoroscopic imaging was used to guide insertion. Each screw was then subjected to caudal cyclic loads of 50N for 2000 cycles at 2Hz. Analysis of initial damage, initial rate, and total damage during cyclic loading was undertaken. Findings Average total fatigue damage for straight screws measured 0.398±0.38 mm, and 0.689±0.96 mm for angled screws. Statistical analysis for total fatigue damage ratio of angled to straight screws revealed that a significant stability was achieved in straight- screw construct (p<0.03). Interpretation This study showed that straight screw insertion results in a more stable pedicle-screw construct. The angled screw insertion technique resulted in more scattered values of damage indicating that the outcome from the angled screw fixation is less predictable. This validates the use of this technique to implant pedicle screws across the axis of the pedicle rather than along the axis, (parallel to the midline sagittal line), and has broad implications in instrumented posterior lumbar spinal surgery. PMID:17208340

Sterba, William; Kim, Do-Gyoon; Fyhrie, David P.; Yeni, Yener N.; Vaidya, Rahul

2007-01-01

253

Wide-angle energy-momentum spectroscopy  

E-print Network

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 (Eu$^{3+}$:Y$_{2}$O$_{3}$) and chromium-doped magnesium oxide (Cr$^{3+}$:MgO). Once extracted, these rates allow us to reconstruct the full, polarized, two-dimensional radi...

Dodson, Christopher M; Li, Dongfang; Zia, Rashid

2014-01-01

254

Edge effects in angle-ply composite laminates  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

255

Design, Fabrication and Testing of Angled Fiber Suspension for Electrostatic Actuators  

E-print Network

aligned combs with distributed fiber supports. Comb drivea distributed support structure composed of angled fibersdistributed, there are some pores that are merged together, resulting in larger radius fibers

Schubert, Bryan Edward

2011-01-01

256

Aspect angle dependence of naturally enhanced ion acoustic lines  

NASA Astrophysics Data System (ADS)

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.

Akbari, H.; Semeter, J. L.

2014-07-01

257

Specular points and critical gimbal angles of ogival radomes  

NASA Astrophysics Data System (ADS)

Results on critical gimbal angles of ogival radomes have been presented as a function of fineness ratios and source point locations. It is shown that, for a given source point and reflected ray direction, no more than two specular points generally exist on the radome inner surface. The critical gimbal angle, beyond which reflected rays contribute to geometrical optics fields, is obtained in terms of a turning-point effect. Critical gimbal angles computed are significantly different from previously published results which overlooked the turning-point effect. Special techniques to determine the contribution of specular points near the turning point are briefly discussed. The techniques proposed can be applied to rotationally symmetric geometries other than ogives.

Rengarajan, Sembiam R.

1988-07-01

258

Spin-orbit angles as a probe to orbital evolution  

NASA Astrophysics Data System (ADS)

The WASP (Wide Angle Search for Planets) has discovered 75 planets in the Southern Hemisphere. We followed-up 40 of these and observed the Rossiter-McLaughlin effect. It allows us to measure the angle between the stellar spin and the planet's orbital spin. Here, we present the results of our survey, along with results published in the literature. Our observations reveal a wide distribution in orbital angle, indicative or past dynamical interactions. Our data also demonstrates the important effects that tidal interactions have in altering the spin-orbit distribution. This renders any interpretation tricky. However, comparing different sub-samples we start uncovering evidence that two types of migration are maybe acting to create the hot Jupiter population.

Triaud, Amaury; Collier Cameron, Andrew; Queloz, Didier; Anderson, David; Brown, David; Smalley, Barry; Bouchy, Francois; Lendl, Monika; Gillon, Michael

2013-07-01

259

Wind-tunnel calibration and requirements for in-flight use of fixed hemispherical head angle-of-attack and angle-of-sideslip sensors  

NASA Technical Reports Server (NTRS)

Wind-tunnel tests were conducted with three different fixed pressure-measuring hemispherical head sensor configurations which were strut-mounted on a nose boom. The tests were performed at free-stream Mach numbers from 0.2 to 3.6. The boom-angle-of-attack range was -6 to 15 deg, and the angle-of-sideslip range was -6 to 6 deg. The test Reynolds numbers were from 3.28 million to 65.6 million per meter. The results were used to obtain angle-of-attack and angle-of-sideslip calibration curves for the configurations. Signal outputs from the hemispherical head sensor had to be specially processed to obtain accurate real-time angle-of-attack and angle-of-sideslip measurements for pilot displays or aircraft systems. Use of the fixed sensors in flight showed them to be rugged and reliable and suitable for use in a high temperature environment.

Montoya, E. J.

1973-01-01

260

Comparison of observed and modeled isoplanatic angles using synoptic weather data  

NASA Astrophysics Data System (ADS)

A comparison of observed and modeled isoplanatic angles using synoptic meteorological data is performed over an annual cycle during 1993 - 1994. Time series of isoplanatic angles were observed during 58 night-time episodes at the Phillips Laboratory (PL) Starfire Optical Range. Isoplanatic angles were also computed for corresponding times by integration of modeled Cn2 vertical profiles derived from the Dewan and Hufnagel models. Both models used adjacent Albuquerque rawinsonde data for model input. Results show significantly smaller model error associated with the Dewan isoplanatic angles than associated with the Hufnagel isoplanatic angles. The Dewan model is also sensitive to tropopause height which is used as part of its scale length determination. Synoptic weather comparisons are accomplished for the winter period of December 1993 - February 1994. The comparisons tend to support the correlation of low isoplanatic angle with disturbed and higher isoplanatic angle with undisturbed synoptic weather patterns, respectively.

Roadcap, John R.; Morgenstern, Carolyn D.

1995-04-01

261

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

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.

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

262

Vision only Presented angle (Visual / Body)  

E-print Network

Vision only Presented angle (Visual / Body) 45º / 30º 60º / 40º 75º / 50º Reproductedrotationangle rotation Vision + Body (same gain) Presented angle (Visual / Body) 45º / 30º 60º / 40º 75º / 50º Reproductedrotationangle(º) 0 10 20 30 40 50 60 70 80 Visual rotation Body rotation Vision + Body (different gain

263

Air entrainment in angled dip coating  

Microsoft Academic Search

The coating flow examined here, labelled angled dip coating, is that where a substrate enters a pool of liquid forming an angle ? with the vertical so that it intersects the liquid along a wetting line which is not perpendicular to the direction of its motion. This flow situation is distinctly different from that where the substrate, inclined in the

Olivier Cohu; Hadj Benkreira

1998-01-01

264

Classification procedure in limited angle tomography system  

SciTech Connect

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.

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

2011-06-23

265

Effective contact angle for rough boundary  

NASA Astrophysics Data System (ADS)

We provide rigorous justification for the classical Wenzel equation for the roughness enhanced effective contact angle. The minimization of the total surface energy is reformulated into a variational problem. As the size of the roughness becomes small, we show convergence of the minimizer. The limiting minimizer and effective contact angle are explicitly calculated to verify the Wenzel equation.

Chen, Xinfu; Wang, Xiao-Ping; Xu, Xianmin

2013-01-01

266

Practical evaluation of action-angle variables  

SciTech Connect

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.

Boozer, A.H.

1984-02-01

267

The Dual-Angle Method for Fast, Sensitive T1 Measurement in Vivo with Low-Angle Adiabatic Pulses  

NASA Astrophysics Data System (ADS)

A new method for measuring T1 based on a measurement of the ratio, R, of the steady-state partially saturated NMR signals acquired at two fixed low flip angles (<90°) and a single sequence-repetition period, TR, is presented, The flip angles are chosen to optimize both the signal-to-noise ratio per unit time relative to the best possible Ernst-angle performance and the sensitivity with which a measurement of R can resolve differences in T1. A flip-angle pair at of around (60°, 15°) yields 70-79% of the maximum achievable Ernst-angle signal-to-noise ratio and a near-linear dependence of R on TR/ T1 with gradient of about 2:1 over the range 0.1 ? TR/ T1 ? 1. Errors in hip-angle and excitation-field ( B1) inhomogeneity result in roughly proportionate errors in the apparent T1. The method is best implemented with adiabatic low-angle pulses such as B1-independent rotation (BIR-4) or BIR-4 phase-cycled (BIRP) pulses, which permit measurements with surface coils. Experimental validation was obtained at 2 T by comparison of unlocalized inversion-recovery and dual-angle proton ( 1H) and phosphorus ( 31P) measurements from vials containing doped water with 0.04 ? T1 ? 2.8 s and from the metabolites in the calf muscles of eight human volunteers. Calf muscle values of 6 ± 0.5 s for phosphocreatine and around 3.7 ± 0.8 s for the adenosine triphosphates (ATP) were in good agreement with inversion-recovery T1 values and values from the literature. Use of the dual-angle method accelerated T1 measurement time by about fivefold over inversion recovery. The dual-angle method was implemented in a one-dimensional localized surface-coil 31P spectroscopy sequence, producing consistent T1 measurements from phantoms, the calf muscle, and the human liver. 31P T1 values of ATP in the livers of six volunteers were about 0.5 ± 0.1 to 0.6 ± 0.2 s: the total exam times were about 35 minutes per subject. The method is ideally suited to low-sensitivity and/or low-concentration moieties, such as in 31P NMR in vivo, where study-time limitations are critical, and for rapid 1H T1 imaging.

Bottomley, P. A.; Ouwerkerk, R.

268

Let's Do It! Using Geostrips and "Angle-Fixers" to Develop Ideas About Shapes and Angles  

ERIC Educational Resources Information Center

Homemade geostrips, "angle-fixers" (cardboard circular sectors) and brass fasteners can be used by students to explore properties of angles, triangles and other polygons. Several games and other activities are suggested. (SD)

Bruni, James V.; Silverman, Helene

1975-01-01

269

[Drugs and closed-angle glaucoma risk].  

PubMed

Closed-angle glaucomas arise among predisposed patients (narrow iridocorneal angle) in response to various stimuli. Most of the attacks are of iatrogenic origin: all the topical and systemic mydriatic drugs can provoke an angle closure glaucoma attack. Dangerous active ingredients with closed-angle glaucoma are active substances with anticholinergic activity (peripheral action, central action, with anticholinergic side-effects), active ingredients with sympathomimetic alpha activity (alpha 1, alpha and beta with indirect effects), and the active ingredients with parasympathomimetic activity (anticholinesterases). The proprietary medicine, whether or not they are included in the French dictionary Vidal((R)), are classified according to the administration route and their different indications. The closed-angle glaucoma risk after administration of these drugs is noted in the items'contraindications and precautions in the summary of the product characteristics enclosed in the marketing authorization. PMID:11965126

Pozzi, D; Giraud, C; Callanquin, M

2002-01-01

270

Changes in suprarenal and infrarenal aortic angles after endovascular aneurysm repair  

PubMed Central

Purpose We investigated whether suprarenal and infrarenal aortic angles change after the endovascular aneurysm repair (EVAR) procedure and during follow-up, and investigated the correlation between infrarenal aortic angle after EVAR and type Ia endoleaks. Methods Data collected on 70 EVAR procedures for a fusiform infrarenal aortic aneurysm performed between May 2006 and December 2012 were supplemented with a retrospective review of charts and radiographs. Results The greater the preoperative infrarenal aortic angle, the greater the suprarenal aortic angle (r = 0.72, P < 0.001). The infrarenal aortic angle decreased after the EVAR procedure and continued to decrease slowly thereafter (all P < 0.001). Suprarenal aortic angle decreased immediately after the EVAR procedure and continued to decrease during the first month (P < 0.001). No differences in angulation were observed based on stent graft type. Type Ia endoleaks occurred with significantly greater incidence in patients with a larger post EVAR infrarenal angle (P = 0.037). Conclusion The infrarenal aortic angle decreased significantly immediately after the EVAR procedure and continued to decrease slowly thereafter. Suprarenal aortic angle decreased immediately after the EVAR procedure and continued to decrease during the first month. We found a correlation between infrarenal and suprarenal aortic angle. Type Ia endoleaks occurred with greater incidence in patients with a larger infrarenal angle immediately after EVAR. PMID:25317415

Lee, Ho Kyun; Chung, Sang Young; Kim, Jea Kyu; Yoo, Sung Hee

2014-01-01

271

The Influence of Dynamic Contact Angle on Wetting Dynamics  

NASA Technical Reports Server (NTRS)

When surface tension forces dominate, and regardless of whether the situation is static or dynamic, the contact angle (the angle the interface between two immiscible fluids makes when it contacts a solid) is the key parameter that determines the shape of a fluid-fluid interface. The static contact angle is easy to measure and implement in models predicting static capillary surface shapes and such associated quantities as pressure drops. By contrast, when the interface moves relative to the solid (as in dynamic wetting processes) the dynamic contact angle is not identified unambiguously because it depends on the geometry of the system Consequently, its determination becomes problematic and measurements in one geometry cannot be applied in another for prediction purposes. However, knowing how to measure and use the dynamic contact angle is crucial to determine such dynamics as a microsystem throughput reliably. In this talk we will present experimental and analytical efforts aimed at resolving modeling issues present in dynamic wetting. We will review experiments that show the inadequacy of the usual hydrodynamic model when a fluid-fluid meniscus moves over a solid surface such as the wall of a small tube or duct. We will then present analytical results that show how to parametrize these problems in a predictive manner. We will illustrate these ideas by showing how to implement the method in numerical fluid mechanical calculations.

Rame, Enrique; Garoff, Steven

2005-01-01

272

Laminar Incompressible Flow Past Parabolic Bodies at Angles of Attack  

NASA Astrophysics Data System (ADS)

Numerical solutions of a two-dimensional steady laminar incompressible flow over semi-infinite parabolic bodies at angles of attack are obtained. All solutions are found by using a modified numerical approach to solve the time-dependent Navier-Stokes equations. A check of our solutions to those that exist in the literature at zero angle of attack showed excellent agreement. In addition, at zero angle of attack far from the leading edge, an expected correspondence to Blasius flow was found. At large enough angles of attack, the flow separated on the suction surface. In all the cases examined, the flow separation was followed by a reattachment that defined a separation zone. An almost linear increase in the streamwise extent of the separation zone occurred with increasing angle of attack. The separation location and extent of the separation zone was a function of the nose Reynolds number. The results indicated that the shape factor could be used to provide a criterion for separation and reattachment in these cases. The characteristics of the separation zone for this geometry proved to be an excellent basic flow to document the effect of leading-edge flow separation on acoustic receptivity of boundary layer instabilities.

Erturk, Ercan; Corke, Thomas; Haddad, Osamah

2003-11-01

273

THz dichroic plates for use at high angles of incidence  

NASA Technical Reports Server (NTRS)

The design of a high frequency dichroic plate consisting of an electrically thick self supporting metallic mesh that can be used in a linearly polarized quasi-optical system at high angles of incidence is described. The measured and computed performance of a 2.5-inch aperture mesh is given. This mesh has a 3-dB cutoff frequency of 875 GHz and less than 0.75 dB of transmission loss from 950-1350 GHz at incidence angles of 0, 30, and 45 degrees. The results of a multimode waveguide analysis corroborate the measured data.

Siegel, Peter H.; Dengler, Robert J.; Chen, Jacqueline C.

1991-01-01

274

Demonstration of angle-dependent Casimir force between corrugations.  

PubMed

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

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

2013-06-21

275

Non-uniform projection angle processing in computed tomography  

NASA Astrophysics Data System (ADS)

In this paper, we present a novel approach for the collection of computed tomography data. Non-uniform increments in projection angle may be used to reduce data acquisition time with minimal reduction in the accuracy of the reconstructed profile. The key is to exploit those projection angles which correspond to regions where the object contains few high spatial frequency components. This technique is applicable to optical phase computed tomography, as well as X-ray computed tomography. We present simulation results on intraocular lenses used in cataract surgery.

Simo, Yanic; Tayag, Tristan J.

276

Magic angles and cross-hatching instability in hydrogel fracture  

E-print Network

The full 2D analysis of roughness profiles of fracture surfaces resulting from quasi-static crack propagation in gelatin gels reveals an original behavior characterized by (i) strong anisotropy with maximum roughness at $V$-independent symmetry-preserving angles, (ii) a sub-critical instability leading, below a critical velocity, to a cross-hatched regime due to straight macrosteps drifting at the same magic angles and nucleated on crack-pinning network inhomogeneities. Step height values are determined by the width of the strain-hardened zone, governed by the elastic crack blunting characteristic of soft solids with breaking stresses much larger that low strain moduli.

Tristan Baumberger; Christiane Caroli; David Martina; Olivier Ronsin

2008-01-10

277

Guidance law against maneuvering targets with intercept angle constraint.  

PubMed

This study explores the guidance law against maneuvering targets with the intercept angle constraint. The limitation of the traditional guidance law, which simply treats the unknown target acceleration as zero, has been analyzed. To reduce this limitation, a linear extended state observer is constructed to estimate the acceleration of the maneuvering target to enhance the tracking performance of the desired intercept angle. Furthermore, a nonsingular terminal sliding mode control scheme is adopted to design the sliding surface, which is able to avoid the singularity in the terminal phase of guidance. Simulation results have demonstrated that the proposed guidance law outperforms the traditional guidance law in the sense that more accurate intercept angle can be achieved. PMID:24773919

Xiong, Shaofeng; Wang, Weihong; Liu, Xiaodong; Wang, Sen; Chen, Zengqiang

2014-07-01

278

Optimum design of 2D micro-angle sensor  

NASA Astrophysics Data System (ADS)

To improve dynamic measurement performance and resolution, an optimum design on two-dimensional (2D) micro-angle sensor based on optical internal-reflection method via critical-angle refractive index measurement is presented in the paper. The noise signals were filtered effectively by modulating laser-driven and demodulating in signal proceeding. The system's accuracy and response speed are improved further by using 16-bit high-precision AD converter and MSP430 CPU which present with a high-speed performance during signals processes such as fitting angle-voltage curve through specific arithmetic, full range and zero point calibration, filter, scaling transformation etc. The experiment results indicated that, dynamic signal measurement range can be up to +/-600arcsec, the measurement resolution can be better than 0.1arcsec, and the repeatability could be better than +/-0.5arcsec.

Liu, Qinggang; Zhao, Heng; Lou, Xiaona; Jiang, Ningchuan; Hu, Xiaotang

2008-12-01

279

Dynamic contact angles of evaporating liquids on heated surfaces  

NASA Astrophysics Data System (ADS)

We studied dynamic apparent contact angle for gravity-driven flow of volatile liquid down a heated inclined plane. The apparent contact line is modeled as the transition region between the mascroscopic film and ultra-thin adsorbed film dominated by disjoining pressure effects. Three commonly used disjoining pressure models are investigated. The dynamic contact angle follows the Tanner's law remarkably well over a range of evaporation conditions. However, deviations from the predictions based on the Tanner's law are found when interface shape changes rapidly in response to rapid changes of the heater temperature. The Marangoni stresses are shown to result in increase of the values of apparent contact angles. Applications of different models of partial wetting to studies of fingering instability in evaporating liquids are also discussed.

Ajaev, Vladimir; Gambaryan-Roisman, Tatiana; Klentzman, Jill; Stephan, Pater

2009-11-01

280

Measuring Non-spherical Airborne Dust with Space-based MISR Multi-angle Imaging.  

NASA Astrophysics Data System (ADS)

Some of the world's largest dust plumes emanate from Northern Eurasian deserts and are expected to increasingly affect Asian ergonomics. Together with field experiments, satellite observations of dust outbreaks, placed into the context of large-scale dust transport modeling, can help understand the impact of mineral dust aerosols on past and present climate and climate predictions in North and Central Asia. Multi-angle instruments such as the Multi-angle Imaging SpectroRadiometer (MISR) provide independent constraints on aerosol properties based on sensitivity to the shape of the scattering phase function. We present an analysis of the Multi-angle Imaging SpectroRadiometer (MISR) Standard Aerosol Retrieval algorithm, updated with new non-spherical dust models (Version 16 and higher). We compare the MISR products with coincident AERONET surface sun-photometer observations taken during the passage of dust fronts. Our analysis shows that during such events MISR retrieves Angstrom exponents characteristic of large particles, having little spectral variation in extinction over the MISR wavelength range (442, 550, 672 and 866 nm channels), as expected. Also, the retrieved fraction of non-spherical particles is very high. This quantity is not retrieved by satellite instruments having only nadir-viewing cameras. We assess whether MISR aerosol optical thickness (AOT) acquired at about 10:30 AM local time, can be used to represent daily mean AOT in dust climate forcing studies, by comparing MISR-retrieved aerosol optical thickness (AOT) with AERONET daily-mean values. We also compare the effect of particle shape on MISR and MODIS dust retrievals, using co-located MISR, MODIS, and AERONET AOTs and Angstrom exponents. In most cases obtained for this study, MODIS had no retrievals due to sun-glint when MISR's narrower swath observed AERONET sties on islands surrounded by dark water. For the few coincident MISR-MODIS-AERONET dark-water, dusty condition retrievals we obtained, the MISR retrievals were in better agreement with AERONET than those from MODIS. Over bright desert sites, MODIS AOTs at visible wavelengths was systematically higher than those of AERONET and MISR. MISR-derived aerosol type mixtures for these cases included non-spherical dust components with high frequency in retrievals over dark water, and slightly lower frequency over land. The frequency with which non-spherical dust models were selected by the algorithm also decreased in dusty regions affected by pollution. Both MISR and MODIS retrievals have a high fail rate over optically thick dust plumes.

Kalashnikova, O. V.; Diner, D. J.; Abdou, W.; Kahn, R.; Gaitley, B. J.; Gasso, S.

2004-12-01

281

Uncertainty incorporated beam angle optimization for IMPT treatment planning  

PubMed Central

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

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

2012-01-01

282

Fracture in angle-ply ceramic matrix composites  

Microsoft Academic Search

An analytical\\/computational fracture mechanics scheme, combined with finite element computations, is presented to explain observed fracture patterns in angle ply fiber-reinforced ceramic composite laminates. Unlike polymeric composites, where microcracks are channeled parallel to the fiber directions, cracks in ceramic composites initiate perpendicularly to the load axis. The results presented herein provide rational explanations for the experimental observations and confirm the

A. S. Selvarathinam; Y. J. Weitsman

2000-01-01

283

Measurements of the angle alpha (phi2) at B factories  

E-print Network

The measurements of the angle alpha (phi2) of the unitarity triangle at the B factories are reviewed. The value of alpha determined by combining the results obtained in the B to pi pi, B to rho pi, and B to rho rho modes by both the BABAR and Belle experiments is (87.5 +6.2 -5.3) degrees.

G. Vasseur

2008-10-02

284

Helicopter rotors pyramid angle measurement based on CMOS technology  

Microsoft Academic Search

Based on computer image processing, give a new method on helicopter rotors pyramid angle by CMOS -Camera. give a overall design of the system, compare image results with different camera's location and analyze the system's qualitative error. design a synchronized system by external synchronized pulse in order to catch the accuracy image and calculate the blade's height differences by filter

Jiang Mai; Cai Cheng-Tao; Zhu Qi-Dan; Shi Zhen

2009-01-01

285

Quantification of the subpubic angle in South Africans.  

PubMed

Due to the high crime rate in South Africa, forensic anthropologists are increasingly approached to aid in the identification of skeletonized remains, with sex and population affinity assignment being some of the most critical tasks they face. For over a century, the pelvis has been known to be one of the most sexually dimorphic bones of the human body and the subpubic angle is one of the most accurate, albeit scarcely quantified, features thereof. Hence, the aim of this study was to quantify the size of the subpubic angle and compare it between male and female South Africans of African (black) and European (white) descent. One hundred and forty five (145) pelves were selected, consisting of 68 white (43 male and 25 female) and 77 black South Africans (44 male and 33 female), from the Raymond A. Dart Collection of Human Skeletons housed at the University of the Witwatersrand, Johannesburg, South Africa. Each of the pelves were articulated and placed into a custom built stand for photographing. Measures of the subpubic angle from these digital images were subjected to numerous statistical analyses. Results indicated that significant differences exist between the sexes, as well as between the two population groups. For black individuals it was found that males generally possessed a subpubic angle of 74.9° or less, with larger values being indicative of the female sex. For white individuals, subpubic angles of 81.4° and less indicated males whilst larger values indicated females, with an average accuracy of 86% for both population groups. These results illustrate the advantages of using the subpubic angle to assist in the estimation of sex and population affinity and also reinforce the need for population specific parameters to be applied. PMID:22749676

Small, Candice; Brits, Desiré M; Hemingway, Jason

2012-10-10

286

Orientation Angles of a Pulsar's Polarization Vector  

E-print Network

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.

Mark M. McKinnon

2006-03-17

287

Phase-angle controller for Stirling engines  

NASA Technical Reports Server (NTRS)

An actuator includes a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a Stirling engine and a crankshaft for the displacer portion of the engine. The restraint link is releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft. A second embodiment incorporates a hydraulic coupler for use in varying the phase angle of gear-coupled crank fpr a Stirling engine whereby phase angle changes are obtainable.

Mcdougal, A. R. (inventor)

1980-01-01

288

Angle sensing with ferromagnetic nanowire arrays  

NASA Astrophysics Data System (ADS)

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.

Tannous, C.; Gieraltowski, J.

2014-01-01

289

Intrarater and Interrater Reliability of the Flexicurve Index, Flexicurve Angle, and Manual Inclinometer for the Measurement of Thoracic Kyphosis  

PubMed Central

Objective. This study aimed to describe the interrater and intrarater reliability of the flexicurve index, flexicurve angle, and manual inclinometer in swimmers. A secondary objective was to determine the level of agreement between the inclinometer angle and the flexicurve angle and to provide an equation to approximate one angle from the other. Methods. Thirty swimmers participated. Thoracic kyphosis was measured using the flexicurve and the manual inclinometer. Intraclass correlation coefficient, 95% confidence interval, and standard error of measurement were computed. Results. The flexicurve angle and index showed excellent intrarater (ICC = 0.94) and good interrater (ICC = 0.86) reliability. The inclinometer demonstrated excellent intrarater (ICC = 0.92) and interrater (ICC = 0.90) reliability. The flexicurve angle was systematically smaller and correlated poorly with the inclinometer angle (R2 = 0.384). The following equations can be used for approximate conversions: flexicurve angle = (0.275 × inclinometer angle) + 8.478; inclinometer angle = (1.396 × flexicurve angle) + 8.694. Conclusion. The inclinometer and flexicurve are both reliable instruments for thoracic kyphosis measurement in swimmers. Although the flexicurve and inclinometer angles are not directly comparable, the approximate conversion factors provided will permit translation of flexicurve angle to inclinometer angle and vice versa. PMID:24396603

Lewis, Jeremy

2013-01-01

290

View angle dependence of cloud optical thicknesses retrieved by MODIS  

NASA Technical Reports Server (NTRS)

This study examines whether cloud inhomogeneity influences the view angle dependence of MODIS cloud optical thickness (tau) retrieval results. The degree of cloud inhomogeneity is characterized through the local gradient in 11 microns brightness temperature. The analysis of liquid phase clouds in a one year long global dataset of Collection 4 MODIS data reveals that while optical thickness retrievals give remarkably consistent results for all view directions if clouds are homogeneous, they give much higher tau-values for oblique views than for overhead views if clouds are inhomogeneous and the sun is fairly oblique. For solar zenith angles larger than 55deg, the mean optical thickness retrieved for the most inhomogeneous third of cloudy pixels is more than 30% higher for oblique views than for overhead views. After considering a variety of possible scenarios, the paper concludes that the most likely reason for the increase lies in three-dimensional radiative interactions that are not considered in current, one-dimensional retrieval algorithms. Namely, the radiative effect of cloud sides viewed at oblique angles seems to contribute most to the enhanced tau-values. The results presented here will help understand cloud retrieval uncertainties related to cloud inhomogeneity. They complement the uncertainty estimates that will start accompanying MODIS cloud products in Collection 5 and may eventually help correct for the observed view angle dependent biases.

Marshak, Alexander; Varnai, Tamas

2005-01-01

291

THE VIEWING ANGLES OF BROAD ABSORPTION LINE VERSUS UNABSORBED QUASARS  

SciTech Connect

It was recently shown that there is a significant difference in the radio spectral index distributions of broad absorption line (BAL) quasars and unabsorbed quasars, with an overabundance of BAL quasars with steeper radio spectra. This result suggests that source orientation does play into the presence or absence of BAL features. In this paper, we provide more quantitative analysis of this result based on Monte Carlo simulations. While the relationship between viewing angle and spectral index does indeed contain a lot of scatter, the spectral index distributions are different enough to overcome that intrinsic variation. Utilizing two different models of the relationship between spectral index and viewing angle, the simulations indicate that the difference in spectral index distributions can be explained by allowing BAL quasar viewing angles to extend about 10 Degree-Sign farther from the radio jet axis than non-BAL sources, though both can be seen at small angles. These results show that orientation cannot be the only factor determining whether BAL features are present, but it does play a role.

DiPompeo, M. A.; Brotherton, M. S. [Department of Physics and Astronomy 3905, University of Wyoming, 1000 E. University, Laramie, WY 82071 (United States); De Breuck, C. [European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei Muenchen (Germany)

2012-06-10

292

Radiative transfer in shrub savanna sites in Niger: Preliminary results from HAPEX-Sahel. Part 3: Optical dynamics and vegetation index sensitivity to biomass and plant cover  

NASA Technical Reports Server (NTRS)

A shrub savannah landscape in Niger was optically characterized utilizing blue, green, red and near-infrared wavelengths. Selected vegetation indices were evaluated for their performance and sensitivity to describe the complex Sahelian soil/vegetation canopies. Bidirectional reflectance factors (BRF) of plants and soils were measured at several view angles, and used as input to various vegetation indices. Both soil and vegetation targets had strong anisotropic reflectance properties, rendering all vegetation index (6) responses to be a direct function of sun and view geometry. Soil background influences were shown to alter the response of most vegetation indices. N-space greenness had the smallest dynamic range in VI response, but the n-space brightness index provided additional useful information. The global environmental monitoring index (GEMI) showed a large 6 dynamic range for bare soils, which was undesirable for a vegetation index. The view angle response of the normalized difference vegetation index (NDVI), atmosphere resistant vegetation index (ARVI) and soil atmosphere resistant vegetation index (SARVI) were asymmetric about nadir for multiple view angles, and were, except for the SARVI, altered seriously by soil moisture and/or soil brightness effects. The soil adjusted vegetation index (SAVI) was least affected by surface soil moisture and was symmetric about nadir for grass vegetation covers. Overall the SAVI, SARVI and the n-space vegetation index performed best under all adverse conditions and were recommended to monitor vegetation growth in the sparsely vegetated Sahelian zone.

vanLeeuwen, W. J. D.; Huete, A. R.; Duncan, J.; Franklin, J.

1994-01-01

293

Impact angle control of interplanetary shock geoeffectiveness  

NASA Astrophysics Data System (ADS)

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.

Oliveira, D. M.; Raeder, J.

2014-10-01

294

A Unified Low-Elevation-Angle Scintillation Model  

NASA Astrophysics Data System (ADS)

Enabling communications at very low elevation angles can lengthen the duration of a tracking pass between a satellite and a ground station, which in turn can increase the amount of data return and possibly reduce the number of required supporting ground station tracking passes. Link performance, especially at very low angles and high frequencies, depends heavily on terrain, atmosphere, and weather conditions. Among the different contributions to attenuation, scintillation fading plays a very significant role and can impair the performance of the link. It is therefore necessary to accurately model the overall impact to the link due to scintillation fading. The current International Telecommunication Union ITU-R P.618-10 Recommendation describes three scintillation loss models as a function of elevation angle and percentage of time for which the loss exceeds a certain threshold. Implementation of the recommendation resulted in the uncovering of several issues. Particularly, it was identified that (i) iterative solutions to an implicit nonlinear exponential model, in some cases, are not guaranteed to exist, (ii) there is a discontinuity in fading values between models at the cross-over elevation angle, (iii) at certain low elevation angles scintillation from the shallow fade model generates unrealistically small losses, and (iv) for elevation angles lying between 4 and 5 deg, there are two applicable scintillation models that yield conflicting values. In this article, we develop a new approach to unify the different fading models within the current ITU recommendation and fully remove the discrepancies. We further validated our models with ITU-adopted scintillation data measured at Goonhilly, Great Britain, and data from several recent NASA Space Shuttle launches. This improved model was provisionally approved at the ITU International Meeting in Italy, November 2010, and is being evaluated by the ITU members for adoption into the next-version ITU Recommendation.

Lee, C. H.; Cheung, K.-M.; Ho, C.

2011-05-01

295

Laser Trabeculoplasty for Open-Angle Glaucoma.  

National Technical Information Service (NTIS)

In the hands of ophthalmologists experienced in this technology, argon laser trabeculoplasty is an appropriate treatment for open-angle glaucoma which remains uncontrolled despite maximal tolerated medical treatment. In view of its relatively low level of...

E. Feigenbaum

1984-01-01

296

A study of rain estimation methods from space using dual-wavelength radar measurements at near-nadir incidence over ocean  

NASA Technical Reports Server (NTRS)

A question arising from the recent interest in spaceborne weather radar is what methods can be used to estimate precipitation parameters from space. In this paper, dual-wavelength airborne radar data obtained from flights conducted during 1988 and 1989 are used to compare rain rates derived from backscattering and attenuation methods. To help interpret the results the surface reference methods are studied by means of scatterplots of the surface cross sections at the two frequencies under rain and no-rain conditions. Approximate criteria are given on combining attenuation and backscattering methods to increase the effective dynamic range of the radar. The dual-wavelength capability of the radar is also used to examine the vertical structure of the precipitation. Another factor affecting the accuracy of the methods is the drop-size distribution. In the final section of the paper a procedure to estimate the profiled drop-size distribution is applied to the measured radar data.

Meneghini, R.; Kozu, T.; Kumagai, H.; Boncyk, W. C.

1992-01-01

297

Influence of clearance and rake angles on the cutting force of rock  

NASA Astrophysics Data System (ADS)

Fundamental rock cutting tests for several types of rock were conducted to determine the influence of clearance and rake angles on cutting force (the horizontal and vertical forces). Bits used in the tests had rake angles of -20, 0, 20 deg., and clearance angles were changed from 0 to 12.5 deg. at each rake angle. Oya tuff, Akiyoshi marble and Sanjome andesite (the uniaxial compressive strength is 110, 740, and 1100 kgf/sq cm, respectively) were cut using each bit at a cutting depth of 0.5 to 2.0 mm and cutting speed of 5m/min. The following results were obtained: (1) minimum clearance angle not affecting cutting force was between 2.5 and 5 deg. for Sanjome andesite and Akiyoshi marble, and between 0 and 1 deg. for Oya tuff; (2) rake angle affected cutting force significantly. For example, the cutting force of the bit with a -20 deg. rake angle decreased about 30 - 80 percent, compared to that of the bit with a -20 deg. rake angle; and (3) increase in cutting force with cutting depth became lower with increase in rake angle. Drag bit performance is shown to improve considerably when the rake and clearance angles are set appropriately based on rock formation conditions.

Ono, Tetsuji; Karasawa, Hirokazu; Misawa, Shigeo

1993-05-01

298

Solar Cell Angle of Incidence Corrections  

NASA Technical Reports Server (NTRS)

The Mars Pathfinder mission has three different solar arrays each of which sees changes in incidence angle during normal operation. When solar array angle of incidence effects was researched little published data was found. The small amount of-published data created a need to obtain and evaluate such data. The donation of the needed data, which was taken in the fall of 1994, was a major factor in the preparation of this paper.

Burger, Dale R.; Mueller, Robert L.

1995-01-01

299

Choroid Plexus Papilloma of the Cerebellopontine Angle  

PubMed Central

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

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

1992-01-01

300

Contact Angle Hysteresis on Superhydrophobic Stripes  

E-print Network

We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, $\\phi_S$. It is shown that the receding regime is determined by a longitudinal sliding motion the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e. is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with $\\phi_S$, in contrast to predictions of the Cassie equation. To interpret this we develop a simple theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the elastic energy of strong defects at the borders of stripes, which scales as $\\phi_S^2 \\ln \\phi_S$. The advancing contact angle was found to be anisotropic, except as in a dilute regime, and its value is determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on $\\phi_S$, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at $\\phi_S\\simeq 0.5$. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be proportional to $\\phi_S^2$. Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when $\\phi_S\\leq 0.2$.

Alexander L. Dubov; Ahmed Mourran; Martin Möller; Olga I. Vinogradova

2014-02-11

301

New angles on D-branes  

SciTech Connect

A low-energy background field solution is presented which describes several D-membranes oriented at angles with respect to one another. The mass and charge densities for this configuration are computed and found to saturate the Bogomol{close_quote}nyi-Prasad-Sommerfeld bound, implying the preservation of one-quarter of the supersymmetries. T duality is exploited to construct new solutions with nontrivial angles from the basic one. {copyright} {ital 1997} {ital The American Physical Society}

Breckenridge, J.C.; Michaud, G.; Myers, R.C. [Department of Physics, McGill University, Ernest Rutherford Physics Building, Montreal, Quebec, H3A 2T8 (CANADA)] [Department of Physics, McGill University, Ernest Rutherford Physics Building, Montreal, Quebec, H3A 2T8 (CANADA)

1997-10-01

302

Testing cosmic microwave background polarization data using position angles  

NASA Astrophysics Data System (ADS)

We consider a novel null test for contamination which can be applied to cosmic microwave background (CMB) polarization data that involves analysis of the statistics of the polarization position angles. Specifically, we will concentrate on using histograms of the measured position angles to illustrate the idea. Such a test has been used to identify systematics in the NRAO-VLA Sky Survey point source catalogue with an amplitude well below the noise level. We explore the statistical properties of polarization angles in CMB maps. If the polarization angle is not correlated between pixels, then the errors follow a simple ?{N_{pix}} law. However, this is typically not the case for CMB maps since these have correlations which result in an increase in the variance as the effective number of independent pixels is reduced. Then, we illustrate how certain classes of systematic errors can result in very obvious patterns in these histograms, and thus that these errors could possibly be identified using this method. We discuss how this idea might be applied in a realistic context, and make a preliminary analysis of the Wilkinson Microwave Anisotropy Probe 7 data, finding evidence of a systematic error in the Q- and W- band data, consistent with a constant offset in Q and U.

Preece, Michael; Battye, Richard A.

2014-10-01

303

Finding a covering triangulation whose maximum angle is provably small  

SciTech Connect

Given a planar straight-line graph, we find a covering triangulation whose maximum angle is as small as possible. A covering triangulation is a triangulation whose vertex set contains the input vertex set and whose edge set contains the input edge set. Such a triangulation differs from the usual Steiner triangulation in that we may not add a Steiner vertex on any input edge. Covering triangulations provide a convenient method for triangulating multiple regions sharing a common boundary, as each region can be triangulated independently. As it is possible that no finite covering triangulation is optimal in terms of its maximum angle, we propose an approximation algorithm. Our algorithm produces a covering triangulation whose maximum angle {gamma} is probably close to {gamma}{sub opt}, a lower bound on the maximum angle in any covering triangulation of the input graph. Note that we must have {gamma} {le} 3{gamma}{sub opt}, since we always have {gamma}{sub opt} {ge} {pi}/3 and no triangulation can contain an angle of size greater than {pi}. We prove something significantly stronger. We show that {pi} {minus} {gamma} {ge} ({pi} {minus} {gamma}{sub opt})/6, i.e., our {gamma} is not much closer to {pi} than is {gamma}{sub opt}. This result represents the first nontrivial bound on a covering triangulation`s maximum angle. We require a subroutine for the following problem: Given a polygon with holes, find a Steiner triangulation whose maximum angle is bounded away from {pi}. No angle larger than 8{pi}/9 is sufficient for the bound on {gamma} claimed above. The number of Steiner vertices added by our algorithm and its running time are highly dependent on the corresponding bounds for the subroutine. Given an n-vertex planar straight-line graph, we require O(n + S(n)) Steiner vertices and O(n log n + T(n)) time, where S(n) is the number of Steiner vertices added by the subroutine and T(n) is its running time for an O(n)-vertex polygon with holes.

Mitchell, S.A.; Park, J.K.

1993-03-03

304

Finding a covering triangulation whose maximum angle is provably small  

SciTech Connect

Given a planar straight-line graph, we find a covering triangulation whose maximum angle is as small as possible. A covering triangulation is a triangulation whose vertex set contains the input vertex set and whose edge set contains the input edge set. Such a triangulation differs from the usual Steiner triangulation in that we may not add a Steiner vertex on any input edge. Covering triangulations provide a convenient method for triangulating multiple regions sharing a common boundary, as each region can be triangulated independently. As it is possible that no finite covering triangulation is optimal in terms of its maximum angle, we propose an approximation algorithm. Our algorithm produces a covering triangulation whose maximum angle [gamma] is probably close to [gamma][sub opt], a lower bound on the maximum angle in any covering triangulation of the input graph. Note that we must have [gamma] [le] 3[gamma][sub opt], since we always have [gamma][sub opt] [ge] [pi]/3 and no triangulation can contain an angle of size greater than [pi]. We prove something significantly stronger. We show that [pi] [minus] [gamma] [ge] ([pi] [minus] [gamma][sub opt])/6, i.e., our [gamma] is not much closer to [pi] than is [gamma][sub opt]. This result represents the first nontrivial bound on a covering triangulation's maximum angle. We require a subroutine for the following problem: Given a polygon with holes, find a Steiner triangulation whose maximum angle is bounded away from [pi]. No angle larger than 8[pi]/9 is sufficient for the bound on [gamma] claimed above. The number of Steiner vertices added by our algorithm and its running time are highly dependent on the corresponding bounds for the subroutine. Given an n-vertex planar straight-line graph, we require O(n + S(n)) Steiner vertices and O(n log n + T(n)) time, where S(n) is the number of Steiner vertices added by the subroutine and T(n) is its running time for an O(n)-vertex polygon with holes.

Mitchell, S.A.; Park, J.K.

1993-03-03

305

Knee angle-dependent oxygen consumption of human quadriceps muscles during maximal voluntary and electrically evoked contractions  

Microsoft Academic Search

Fatigability and muscle oxygen consumption (mVO2) during sustained voluntary isometric knee extensions are less at extended (30° knee angle; 0°, full extension) versus flexed\\u000a knee angles (90°). This lower energy consumption may partially result from lower neural activation at extended knee angles.\\u000a We hypothesized a smaller difference in mVO2 between extended and flexed knee angles during electrical stimulation, which guaranteed

R. D. Kooistra; C. J. de Ruiter; A. de Haan

2008-01-01

306

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

307

Asymmetric dihedral angle offsets for large-size lunar laser ranging retroreflectors  

NASA Astrophysics Data System (ADS)

The distribution of two-dimensional velocity aberration is off-centered by 5 to 6 microradians in lunar laser ranging, due to the stable measurement geometry in the motion of the Earth and the Moon. The optical responses of hollow-type retroreflectors are investigated through numerical simulations, especially focusing on large-size, single-reflector targets that can ultimately minimize the systematic error in future lunar laser ranging. An asymmetric dihedral angle offset, i.e. setting unequal angles between the three back faces, is found to be effective for retroreflectors that are larger than 100 mm in diameter. Our numerical simulation results reveal that the optimized return energy increases approximately 3.5 times more than symmetric dihedral angle cases, and the optimized dihedral angle offsets are 0.65-0.8 arcseconds for one angle, and zeroes for the other two angles.

Otsubo, T.; Kunimori, H.; Noda, H.; Hanada, H.; Araki, H.; Katayama, M.

2011-08-01

308

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

PubMed

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

Manor, Ofer

2014-06-17

309

Segment adaptive gradient angle interpolation.  

PubMed

We introduce a new edge-directed interpolator based on locally defined, straight line approximations of image isophotes. Spatial derivatives of image intensity are used to describe the principal behavior of pixel-intersecting isophotes in terms of their slopes. The slopes are determined by inverting a tridiagonal matrix and are forced to vary linearly from pixel-to-pixel within segments. Image resizing is performed by interpolating along the approximated isophotes. The proposed method can accommodate arbitrary scaling factors, provides state-of-the-art results in terms of PSNR as well as other quantitative visual quality metrics, and has the advantage of reduced computational complexity that is directly proportional to the number of pixels. PMID:23192557

Zwart, Christine M; Frakes, David H

2013-08-01

310

Comparison of the Forward Head Angle and the Lumbar Flexion and Rotation Angles of Computer Workers Using Routine and Individually Fixed Computer Workstations  

PubMed Central

[Purpose] This study compared the forward head angle and the lumbar flexion and rotation angles of computer workers using routine and fixed computer workstations. [Subjects] Ten male workers voluntarily consented to participate in the study. [Methods] A 3-D motion analysis system was used to measure the angles of the forward head and lumbar flexion. All subjects performed computer work for 30 minutes using both types of workstation. [Results] When working at the fixed workstation, the forward head angle was less than that observed when the routine workstation was used. At the fixed workstation, the lumbar flexion and rotation angles were less than that at the routine workstation. [Conclusion] The computer workstation individually fixed for standard posture may have prevented poor sitting posture. PMID:24707097

Yoo, Won-gyu

2014-01-01

311

Noise of the SR-3 propeller model at 2 deg and 4 deg angle of attack  

NASA Technical Reports Server (NTRS)

The noise effect of operating supersonic tip speed propellers at angle of attack with respect to the incoming flow was determined. Increases in the maximum blade passage noise were observed for the propeller operating at angle of attack. The noise increase was not symmetrical with one wall of the wind tunnel having significantly more noise increase than the other wall. This was apparently the result of the rotational direction of the propeller. The lack of symmetry of the noise at angle of attack to the use of oppositely rotating propellers on opposite sides of an airplane fuselage as a way of minimizing the noise due to operation at angle of attack.

Dittmar, J. H.; Jeracki, R. J.

1981-01-01

312

Intermittent acute angle closure glaucoma and chronic angle closure following topiramate use with plateau iris configuration  

PubMed Central

This is a case report describing recurrent intermittent acute angle closure episodes in the setting of topiramate use in a female suffering from migraines. Despite laser peripheral iridotomy placement for the pupillary block component, and the discontinuation of topiramate, the acute angle closure did not resolve in the left eye with chronic angle closure and the patient required urgent trabeculectomy. The right eye responded to laser peripheral iridotomy immediately and further improved after the cessation of topiramate. While secondary angle closure glaucoma due to topiramate use has been widely reported, its effects in patients with underlying primary angle closure glaucoma have not been discussed. Our report highlights the importance of recognizing the often multifactorial etiology of angle closure glaucoma to help guide clinical management. PMID:25114497

Rajjoub, Lamise Z; Chadha, Nisha; Belyea, David A

2014-01-01

313

Effectiveness of Variable-Gain Kalman Filter Based on Angle Error Calculated from Acceleration Signals in Lower Limb Angle Measurement with Inertial Sensors  

PubMed Central

The wearable sensor system developed by our group, which measured lower limb angles using Kalman-filtering-based method, was suggested to be useful in evaluation of gait function for rehabilitation support. However, it was expected to reduce variations of measurement errors. In this paper, a variable-Kalman-gain method based on angle error that was calculated from acceleration signals was proposed to improve measurement accuracy. The proposed method was tested comparing to fixed-gain Kalman filter and a variable-Kalman-gain method that was based on acceleration magnitude used in previous studies. First, in angle measurement in treadmill walking, the proposed method measured lower limb angles with the highest measurement accuracy and improved significantly foot inclination angle measurement, while it improved slightly shank and thigh inclination angles. The variable-gain method based on acceleration magnitude was not effective for our Kalman filter system. Then, in angle measurement of a rigid body model, it was shown that the proposed method had measurement accuracy similar to or higher than results seen in other studies that used markers of camera-based motion measurement system fixing on a rigid plate together with a sensor or on the sensor directly. The proposed method was found to be effective in angle measurement with inertial sensors. PMID:24282442

Watanabe, Takashi

2013-01-01

314

Analysis of Slug Test Response in a Fracture of a Large Dipping Angle  

NASA Astrophysics Data System (ADS)

A number of cross-borehole slug tests were conducted in a Cenozoic folded sandstone formation, where a fracture has a dipping angle as large as 47°. As all the slug test models available in literature assume the formation to be horizontal, a slug test model taking into account the dipping angle effect is developed herein. Due to the presence of the dipping angle, there is a uniform regional groundwater flow, and the flow field generated by the test is not raidally symmetrical with respect to the test well. When the fracture hydraulic conductivity is relatively low, a larger dipping angle causes larger wellbore flow rates, leading to a faster recovery of the non-oscillatory test response. When the fracture hydraulic conductivity is relatively high, a larger dipping angle causes smaller wellbore heads, resulting in an increase of amplitude of the oscillatory test response; yet little influence on the frequency of oscillation. In general, neglecting the dipping angle may lead to an overestimate of hydraulic conductivity and an underestimate of the storage coefficient. The dipping angle effect is more pronounced for a larger storage coefficient, being less sensitive to transmissivity. An empirical relationship is developed for the minimum dipping angle, smaller than which the dipping angle effect can be safely neglected, as a function of the dimensionless storage coefficient. This empirical relationship helps evaluate whether or not the dipping angle needs to be considered in data analysis. The slug test data in the fracture of a 47°dipping angle is analyzed using the current model, and it is found that neglecting the dip angle can result in a 30% overestimate of transmissivity and a 61% underestimate of the storage coefficient.

Chen, C.

2013-12-01

315

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

Microsoft Academic Search

Patellar malalignment is the most important reason for anterior knee pain. Patellar alignment is commonly determined by the\\u000a measurement of the quadriceps (Q) angle. In this study, our primary aim was to investigate the Q angle difference between\\u000a healthy individuals with and without joint hypermobility. The other objectives were to compare the Q angle values, which were\\u000a measured in supine

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

2006-01-01

316

Acquisition and analysis of angle-beam wavefield data  

NASA Astrophysics Data System (ADS)

Angle-beam ultrasonic testing is a common practical technique used for nondestructive evaluation to detect, locate, and characterize a variety of material defects and damage. Greater understanding of the both the incident wavefield produced by an angle-beam transducer and the subsequent scattering from a variety of defects and geometrical features is anticipated to increase the reliability of data interpretation. The focus of this paper is on acquiring and analyzing propagating waves from angle-beam transducers in simple, defect-free plates as a first step in the development of methods for flaw characterization. Unlike guided waves, which excite the plate throughout its thickness, angle-beam bulk waves bounce back and forth between the plate surfaces, resulting in the well-known multiple "skips" or "V-paths." The experimental setup consists of a laser vibrometer mounted on an XYZ scanning stage, which is programmed to move point-to-point on a rectilinear grid to acquire waveform data. Although laser vibrometry is now routinely used to record guided waves for which the frequency content is below 1 MHz, it is more challenging to acquire higher frequency bulk waves in the 1-10 MHz range. Signals are recorded on the surface of an aluminum plate that were generated from a 5 MHz, 65° refracted angle, shear wave transducer-wedge combination. Data are analyzed directly in the x-t domain, via a slant stack Radon transform in the ?-p (offset time-slowness) domain, and via a 2-D Fourier transform in the ?-k domain, thereby enabling identification of specific arrivals and modes. Results compare well to those expected from a simple ray tracing analysis except for the unexpected presence of a strong Rayleigh wave.

Dawson, Alexander J.; Michaels, Jennifer E.; Levine, Ross M.; Chen, Xin; Michaels, Thomas E.

2014-02-01

317

Relating dynamic contact angle to wetting front instability  

NASA Astrophysics Data System (ADS)

Dynamic contact angles have been implied as a mechanism for initiating the instability of wetting fronts and the formation of gravity fingers/columns in porous media. To study those dynamic contact angles when gravity effects are present, rectangular capillary tubes are used to facilitate the observation of the complete interface without geometric distortion. Results show that the dynamic contact angle minus the static contact angle has a unique relationship with the capillary number which is function of the velocity of the slug, and surface tension and viscosity of the fluid. Using this relationship and making the assumption that the fluid velocity through the pores is related but not equal to the finger velocity, earlier findings of DiCarlo on the capillary overshoot at the wetting front can be reproduced well. This study confirms that dynamic contact plays a critical role in the formation of unstable finger flow. It also points a way to calculate the capillary pressure at the wetting from as a function of the flux in the finger and the grain size diameter.

Baver, Christine; Parlange, J.-Yves; Stoof, Cathelijne; DiCarlo, David; Wallach, Rony; Steenhuis, Tammo

2013-04-01

318

Tropospheric Emission Spectrometer nadir spectral radiance comparisons  

E-print Network

of the Tropospheric Emission Spectrometer (TES) on board the Aura spacecraft is upwelling infrared spectral radiances selected, nearly coincident spectral radiance measurements from Atmospheric Infrared Sounder (AIRS) on Aqua differences for higher-frequency TES 1A1 filter, which has less upwelling radiance signal. The TES/ AIRS

319

Macromolecular conformational dynamics in torsional angle space  

NASA Astrophysics Data System (ADS)

A Brownian dynamics treatment in torsional angle space is presented for the simulation of conformational dynamics of macromolecules with fixed bond lengths and bond angles and with an arbitrary intramolecular potential energy function. The advantages of the torsional angle space treatment over similar treatments (Brownian dynamics or molecular dynamics) in atomic coordinate space are that, first, the number of variables is reduced by roughly a factor of 10 and, second, the integration time step size is increased by 3 to 4 orders of magnitude (because, by confining the treatment to the torsional angle space, the time step size is not limited by the fast oscillation modes of covalent bonds but rather by the slow motion of macromolecular segments whose time scale is roughly 3 to 4 orders of magnitude larger than that of bond oscillations). Consequently, the exploration of global conformational relaxation processes becomes computationally possible. The treatment is tested by studying the folding kinetics of off-lattice chains with fixed bond lengths and bond angles and with prescribed sequences. The present treatment is a general purpose one applicable to all macromolecular conformational relaxation processes (e.g., protein folding kinetics, drug/ligand docking on to target proteins, conformational multiple-minima problems, etc.). It serves as a complement to the molecular dynamics or Brownian dynamics treatments in atomic coordinate space.

He, Siqian; Scheraga, Harold A.

1998-01-01

320

Determining Skeletal Parameters in Angle Classes II, Division 1 and II, Division 2  

Microsoft Academic Search

Aim: Aim of the study was to find out whether significant differences in skeletal morphology exist between Angle Class II, Division 1 and II, Division 2. Material and Method: Fifty-nine patients without previous orthodontic treatment showing Class II occlusion and distobasal jaw relation were evaluated by cephalometric analysis. Results: Significant differences existed in skeletal morphology between patients with Angle Class

Jörg A. Lisson; Christian Pyka

2005-01-01

321

Corresponding Author: scooke@uiuc.edu Physiological Impacts of Catch-and-Release Angling  

E-print Network

angling related stressors and then monitored their recovery using both cardiac output devices of exhaustion and varies with water temperature. Our results also suggest that air exposure, especially and community level, our assessment of various angling, handling and retention practices identifies ways

Cooke, Steven J.

322

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

Microsoft Academic Search

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

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

2008-01-01

323

Modeling of occurrence frequencies of ion conics as a function of altitude and conic angle  

E-print Network

Modeling of occurrence frequencies of ion conics as a function of altitude and conic angle W / Accepted: 22 July 1999 Abstract. The occurrence frequencies of dayside ion conics with various conic angles conic evolution to match the observation results. The ob- served occurrence frequencies of ion conics

Paris-Sud XI, Université de

324

A Novel Algorithm for Estimating the Rotation Angle in ISAR Imaging  

Microsoft Academic Search

A novel algorithm for estimating the rotation angle in inverse synthetic aperture radar imaging by generally considering the received signals as cubic phase signals is presented. The rotation angle is determined by the coefficients of the cubic phase signals, and the results of real data demonstrate the validity of the algorithm.

Yong Wang; Yicheng Jiang

2008-01-01

325

Multi-angle data from CHRIS\\/Proba for determination of canopy structure in desert rangelands  

Microsoft Academic Search

Multi-angle spectral radiance images from the Compact High Resolution Imaging Spectrometer (CHRIS) on the European Space Agency's Proba satellite were acquired over desert grasslands in the USDA, ARS Jornada Experimental Range near Las Cruces, New Mexico, USA. The data were used to obtain multi-angle ratio images and to effect spatial bidirectional reflectance distribution function (BRDF) model inversions. The results show

Mark Chopping; Andrea Laliberte; Albert Rango

2004-01-01

326

The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer  

PubMed Central

Background Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer. Methods We evaluated a case series of 73 stages III and IV colorectal cancer patients. Patients were classified as either well-nourished or malnourished using the SGA. BIA was conducted on all patients and phase angle was calculated. The correlation between phase angle and SGA was studied using Spearman correlation coefficient. Receiver Operating Characteristic curves were estimated using the non-parametric method to determine the optimal cut-off levels of phase angle. Results Well-nourished patients had a statistically significantly higher (p = 0.005) median phase angle score (6.12) as compared to those who were malnourished (5.18). The Spearman rank correlation coefficient between phase angle and SGA was found to be 0.33 (p = 0.004), suggesting better nutritional status with higher phase angle scores. A phase angle cut-off of 5.2 was 51.7% sensitive and 79.5% specific whereas a cut-off of 6.0 was 82.8% sensitive and 54.5% specific in detecting malnutrition. Interestingly, a phase angle cut-off of 5.9 demonstrated high diagnostic accuracy in males who had failed primary treatment for advanced colorectal cancer. Conclusion Our study suggests that bioimpedance phase angle is a potential nutritional indicator in advanced colorectal cancer. Further research is needed to elucidate the optimal cut-off levels of phase angle that can be incorporated into the oncology clinic for better nutritional evaluation and management. PMID:18590554

Gupta, Digant; Lis, Christopher G; Dahlk, Sadie L; King, Jessica; Vashi, Pankaj G; Grutsch, James F; Lammersfeld, Carolyn A

2008-01-01

327

The Effects of Approach Angle on Penalty Kicking Accuracy and Kick Kinematics with Recreational Soccer Players  

PubMed Central

Kicking accuracy is an important component of successful penalty kicks, which may be influenced by the approach angle. The purpose of this study was to examine the effects of approach angle on kicking accuracy and three-dimensional kinematics of penalty kicks. Seven male amateur recreational soccer players aged (mean ± s) 26 ± 3 years, body mass 74.0 ± 6.8 kg, stature 1.74 ± 0.06 m, who were right foot dominant, kicked penalties at a 0.6 x 0.6 m target in a full size goal from their self-selected approach angle, 30°, 45° and 60° (direction of the kick was 0°). Kicking accuracy and three-dimensional kinematics were recorded. Results revealed that there was no significant difference in kicking accuracy (p = 0.27) or ball velocity (p = 0.59) between the approach angles. Pelvic rotation was significantly greater under the 45° and the 60° approach angles than during the self-selected approach angle (p < 0.05). Thigh abduction of the kicking leg at impact using the 60° approach angle was significantly greater than during the self- selected approach (p = 0.01) and the 30° approach (p = 0.04). It was concluded that altering an individual’s self-selected approach angle at recreational level did not improve kicking accuracy or ball velocity, despite altering aspects of underlying technique. Key points Penalty kicking accuracy and ball velocity were not improved by altering recreational soccer players’ natural approach angle. However, widening the approach angle produced greater pelvic rotation and thigh abduction. Wider approach angles increased the range of motion of the pelvis, opening up the hips before ball contact, creating a greater arc of movement during the backswing and the follow-through. Wider approach angles also led to an increase in thigh abduction at impact, enabling the kicking foot to be placed further under the ball, which may improve ball contact. PMID:24149531

Scurr, Joanna; Hall, Ben

2009-01-01

328

A heterodyne interferometer for angle metrology.  

PubMed

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

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

2010-04-01

329

A heterodyne interferometer for angle metrology  

SciTech Connect

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/{radical}(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 {mu}rad rms, respectively.

Hahn, Inseob; Weilert, M.; Wang, X.; Goullioud, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

2010-04-15

330

Small Angle X-Ray Scattering Detector  

DOEpatents

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., qmax/qmin approx=lO0.

Hessler, Jan P.

2004-06-15

331

Analysis of Oscillatory Slug Test Data in Fractures of a High Dip Angle  

NASA Astrophysics Data System (ADS)

A number of cross-borehole slug tests were conducted in a fractured formation. The fractures are highly permeable, as indicated by the oscillatory responses in both the test and nearby observation wells. The fractures under investigation have a high dip angle, and a mathematical model is developed which takes into account the dip angle and the inertial forces in the test and observation wells. For the test well, it is found that (1) the test response does not change significantly when the dip angle is less than about 45 degrees, (2) when the dip angle is larger than 45 degrees; however, the amplitude and the time lag increase with the dip angle, (3) when the dip angle is greater than about 56 degrees, aquifer storativity becomes negligible, as the significant flow due to the dip angle plays a substitutionary role of aquifer storativity, and (4) neglecting the dip angle can result in an overestimate of hydraulic conductivity and an underestimate of aquifer storativity. For the observation wells, the influence of the dip angle is more complicated, depending on the location of the observation well (e.g., up-gradient or down-gradient to the test well, the distance and direction to the test well). In general, the up-gradient test response will have smaller amplitude and larger time lag than does the down-gradient test response.

Chen, C.-S.

2012-04-01

332

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

333

Rapid emission angle selection for rotating-shield brachytherapy  

SciTech Connect

Purpose: The authors present a rapid emission angle selection (REAS) method that enables the efficient selection of the azimuthal shield angle for rotating shield brachytherapy (RSBT). The REAS method produces a Pareto curve from which a potential RSBT user can select a treatment plan that balances the tradeoff between delivery time and tumor dose conformity. Methods: Two cervical cancer patients were considered as test cases for the REAS method. The RSBT source considered was a Xoft Axxent{sup TM} electronic brachytherapy source, partially shielded with 0.5 mm of tungsten, which traveled inside a tandem intrauterine applicator. Three anchor RSBT plans were generated for each case using dose-volume optimization, with azimuthal shield emission angles of 90 Degree-Sign , 180 Degree-Sign , and 270 Degree-Sign . The REAS method converts the anchor plans to treatment plans for all possible emission angles by combining neighboring beamlets to form beamlets for larger emission angles. Treatment plans based on exhaustive dose-volume optimization (ERVO) and exhaustive surface optimization (ERSO) were also generated for both cases. Uniform dwell-time scaling was applied to all plans such that that high-risk clinical target volume D{sub 90} was maximized without violating the D{sub 2cc} tolerances of the rectum, bladder, and sigmoid colon. Results: By choosing three azimuthal emission angles out of 32 potential angles, the REAS method performs about 10 times faster than the ERVO method. By setting D{sub 90} to 85-100 Gy{sub 10}, the delivery times used by REAS generated plans are 21.0% and 19.5% less than exhaustive surface optimized plans used by the two clinical cases. By setting the delivery time budget to 5-25 and 10-30 min/fx, respectively, for two the cases, the D{sub 90} contributions for REAS are improved by 5.8% and 5.1% compared to the ERSO plans. The ranges used in this comparison were selected in order to keep both D{sub 90} and the delivery time within acceptable limits. Conclusions: The REAS method enables efficient RSBT treatment planning and delivery and provides treatment plans with comparable quality to those generated by exhaustive replanning with dose-volume optimization.

Liu, Yunlong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung; Bhatia, Sudershan K.; Sun, Wenqing [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Yang Wenjun [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States); Wu Xiaodong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

2013-05-15

334

Rapid emission angle selection for rotating-shield brachytherapy  

PubMed Central

Purpose: The authors present a rapid emission angle selection (REAS) method that enables the efficient selection of the azimuthal shield angle for rotating shield brachytherapy (RSBT). The REAS method produces a Pareto curve from which a potential RSBT user can select a treatment plan that balances the tradeoff between delivery time and tumor dose conformity. Methods: Two cervical cancer patients were considered as test cases for the REAS method. The RSBT source considered was a Xoft AxxentTM electronic brachytherapy source, partially shielded with 0.5 mm of tungsten, which traveled inside a tandem intrauterine applicator. Three anchor RSBT plans were generated for each case using dose-volume optimization, with azimuthal shield emission angles of 90°, 180°, and 270°. The REAS method converts the anchor plans to treatment plans for all possible emission angles by combining neighboring beamlets to form beamlets for larger emission angles. Treatment plans based on exhaustive dose-volume optimization (ERVO) and exhaustive surface optimization (ERSO) were also generated for both cases. Uniform dwell-time scaling was applied to all plans such that that high-risk clinical target volume D90 was maximized without violating the D2cc tolerances of the rectum, bladder, and sigmoid colon. Results: By choosing three azimuthal emission angles out of 32 potential angles, the REAS method performs about 10 times faster than the ERVO method. By setting D90 to 85–100 Gy10, the delivery times used by REAS generated plans are 21.0% and 19.5% less than exhaustive surface optimized plans used by the two clinical cases. By setting the delivery time budget to 5–25 and 10–30 min/fx, respectively, for two the cases, the D90 contributions for REAS are improved by 5.8% and 5.1% compared to the ERSO plans. The ranges used in this comparison were selected in order to keep both D90 and the delivery time within acceptable limits. Conclusions: The REAS method enables efficient RSBT treatment planning and delivery and provides treatment plans with comparable quality to those generated by exhaustive replanning with dose-volume optimization. PMID:23635268

Liu, Yunlong; Flynn, Ryan T.; Yang, Wenjun; Kim, Yusung; Bhatia, Sudershan K.; Sun, Wenqing; Wu, Xiaodong

2013-01-01

335

Everything SAXS: small-angle scattering pattern collection and correction  

NASA Astrophysics Data System (ADS)

For obtaining reliable nanostructural details of large amounts of sample—and if it is applicable—small-angle scattering (SAS) is a prime technique to use. It promises to obtain bulk-scale, statistically sound information on the morphological details of the nanostructure, and has thus led to many a researcher investing their time in it over the last eight decades of development. Due to pressure from scientists requesting more details on increasingly complex nanostructures, as well as the ever improving instrumentation leaving less margin for ambiguity, small-angle scattering methodologies have been evolving at a high pace over the past few decades. As the quality of any results can only be as good as the data that go into these methodologies, the improvements in data collection and all imaginable data correction steps are reviewed here. This work is intended to provide a comprehensive overview of all data corrections, to aid the small-angle scatterer to decide which are relevant for their measurement and how these corrections are performed. Clear mathematical descriptions of the corrections are provided where feasible. Furthermore, as no quality data exist without a decent estimate of their precision, the error estimation and propagation through all these steps are provided alongside the corrections. With these data corrections, the collected small-angle scattering pattern can be made of the highest standard, allowing for authoritative nanostructural characterization through its analysis. A brief background of small-angle scattering, the instrumentation developments over the years, and pitfalls that may be encountered upon data interpretation are provided as well.

Pauw, Brian Richard

2013-09-01

336

4.MD,G Measuring Angles  

NSDL National Science Digital Library

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: Draw an angle that measures 60 degrees like the one shown here: Draw another angle that measures 25 degrees. It should have the same vertex and share s...

337

Ship wakes: Kelvin or Mach angle?  

E-print Network

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.

Rabaud, Marc

2013-01-01

338

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

339

Spectral characteristics of low-angle radar ground clutter  

Microsoft Academic Search

A detailed analysis of low-angle ground clutter spectral characteristics was carried out using the MIT Lincoln Lab Phase 1 data and the DREO S-band clutter data. Both the fast Fourier transform and a super-resolution spectral analysis technique were used. Results showed that a ground clutter spectrum comprises three components, namely: (1) a coherent component; (2) a slow-diffuse component; and (3)

H. C. Chan

1989-01-01

340

The small angle neutron spectrometer at the HANARO reactor, Korea  

NASA Astrophysics Data System (ADS)

A new small angle neutron spectrometer (SANS) has been installed on the CN beam tube at the 30 MW HANARO Research Reactor in the Korea Atomic Energy Research Institute (KAERI). The SANS is to be used for the study of microstructural inhomogeneities in materials in the 1 nm to 100 nm size range. In this paper, the design characteristics of the spectrometer are presented in detail, and several SANS results for standard samples are presented which illustrate its performance.

Seong, B.-S.; Han, Y.-S.; Lee, C.-H.; Lee, J.-S.; Hong, K.-P.; Park, K.-N.; Kim, H.-J.

341

Pneumatic vortical flow control at high angles of attack  

NASA Technical Reports Server (NTRS)

The injection of thin, high-momentum jets of air into the fuselage forebody boundary layers of the F-18 aircraft is explored numerically as a means of controlling the onset of fuselage vortices and of generating yaw control forces. The study was carried out for an angle of attack of 30 deg with symmetrical and asymmetrical blowing configurations. One-sided blowing results in a strongly asymmetrical flow pattern in the fore portion of the fuselage, leading to a net lateral force.

Tavella, Domingo A.; Schiff, Lewis B.; Cummings, Russell M.

1990-01-01

342

Atmospheric variations in muon intensity for different zenith angles  

Microsoft Academic Search

The barometric and temperature coefficients of muon intensity for a layer of variable mass and the temperature coefficients\\u000a for mass-weighted mean atmospheric temperature are found by regressions analysis from the results of continuous measurements\\u000a of muon intensity at different zenith angles and atmospheric parameters. The temperature coefficients of muon intensity are\\u000a determined for different atmospheric layers. Using the characteristics obtained,

V. L. Yanchukovsky; G. Ya. Filimonov; R. Z. Hisamov

2007-01-01

343

What is the apparent angle of a Kelvin ship wave pattern?  

NASA Astrophysics Data System (ADS)

While the half-angle which encloses a Kelvin ship wave pattern is commonly accepted to be 19.47 degrees, recent observations and calculations for sufficiently fast-moving ships suggest that the apparent wake angle decreases with ship speed. One explanation for this decrease in angle relies on the assumption that a ship cannot generate wavelengths much greater than its hull length. An alternative interpretation is that the wave pattern that is observed in practice is defined by the location of the highest peaks; for wakes created by sufficiently fast-moving objects, these highest peaks no longer lie on the outermost divergent waves, resulting in a smaller apparent angle. In this paper, we focus on the problems of free surface flow past a single submerged point source and past a submerged source doublet. In the linear version of these problems, we measure the apparent wake angle formed by the highest peaks, and observe the following three regimes: a small Froude number pattern, in which the divergent waves are not visible; standard wave patterns for which the maximum peaks occur on the outermost divergent waves; and a third regime in which the highest peaks form a V-shape with an angle much less than the Kelvin angle. For nonlinear flows, we demonstrate that nonlinearity has the effect of increasing the apparent wake angle so that some highly nonlinear solutions have apparent wake angles that are greater than Kelvin's angle. For large Froude numbers, the effect on apparent wake angle can be more dramatic, with the possibility of strong nonlinearity shifting the wave pattern from the third regime to the second. We expect our nonlinear results will translate to other more complicated flow configurations, such as flow due to a steadily moving closed body such as a submarine.

Pethiyagoda, Ravindra; McCue, Scott W.; Moroney, Timothy J.

2014-11-01

344

Angle-resolved effective potentials for disk-shaped molecules  

E-print Network

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.

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

2014-07-16

345

Transients in wide-angle conical antennas  

Microsoft Academic Search

The response of an antenna to dc pulse excitation, both in reception and in transmission, can be determined by use of Fourier transforms provided the complex impedance and complex effective height of the antenna are known over the frequency range where the excitation has significant components. We have computed the time history of the response of a wide-angle conical antenna

1965-01-01

346

Points, Lines, and Angles, Oh My!  

NSDL National Science Digital Library

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.

Pease, Victoria

2012-08-02

347

Wide angle zoom for the Space Shuttle  

Microsoft Academic Search

In order to pilot and visually monitor the Canadarm operating on the Shuttle, a zoom lens with a minimum wide angle of 98 deg field of view was needed. The design of the chosen solution is presented. There are 22 lenses arranged in 4 groups allowing mechanical compensation. The range of focal lengths is 8.2 to 25 mm; the aperture

J. Angenieux; J. Debize; A. Masson

1983-01-01

348

Quantum Critical Transport and the Hall Angle  

E-print Network

In this brief note we point out that transport properties near a strongly interacting quantum critical point can exhibit a dichotomy in timescales. In particular, when the DC conductivity is dominated by the critical point, the Hall angle will show an anomalous scaling. We support these general considerations by performing exact calculations of the Hall conductivity for a large class of holographic lattice models.

Mike Blake; Aristomenis Donos

2014-06-06

349

Quantum Critical Transport and the Hall Angle  

E-print Network

In this brief note we point out that transport properties near a strongly interacting quantum critical point can exhibit a dichotomy in timescales. In particular, when the DC conductivity is dominated by the critical point, the Hall angle will show an anomalous scaling. We support these general considerations by performing exact calculations of the Hall conductivity for a large class of holographic lattice models.

Blake, Mike

2014-01-01

350

ANTERIOR KNEE PAIN RELATIONSHIP WITH Q ANGLE  

Microsoft Academic Search

Anterior knee pain one of the most friquent patient group for physician who deal with musculesceletal system. Presence of many reason of anterior knee pain ,leads many diffuculties in evaluation of this pain. Purpose of this study is to evaluate increase in Q angle whom is comman and contribution to anterior knee pain.50 patients with pain and 50 pain free

Atakan ÖZKAN; Devlet Hastanesi

351

Angled Tip for a Scanning Force Microscope.  

National Technical Information Service (NTIS)

A microscope probe includes a cantilever having a carbon nanostructure attached thereto at a distally oriented angle. A method of making the microscope probe can include the steps of: providing a cantilever; depositing a masking layer on a surface of the ...

H. Cui

2004-01-01

352

Characterization of blade Bragg grating modeling with different incident angle profiles for strain sensor applications  

NASA Astrophysics Data System (ADS)

This paper presents some preliminary results of sensing properties of single-mode silica blade Bragg gratings model which is coated by a poly(methyl methacrylate). The proposed mathematic model of blade Bragg gratings consists of alternated periodic slabs waveguide with inclined angle and is analyzed by using the principle of multilayer transfer matrix for photonic crystal. By varying the incident angle, the slabs angle, the proposed model is simulated for all of the parameters, regarding to the sensor applications. The simulation results were shown and discussed. According to the simulation results, this model can be used for sensitive stain sensor applications.

Cheamanunkul, Niparat; Srinuanjan, Keerayoot; Yupapin, Preecha P.

2014-08-01

353

Probe Without Moving Parts Measures Flow Angle  

NASA Technical Reports Server (NTRS)

The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle probe (FLAP), a novel, force-based instrument for the measurement of local flow direction. Containing no moving parts, the FLAP may provide greater simplicity, improved accuracy, and increased measurement access, relative to conventional moving vane-type flow-angle probes. Forces in the FLAP can be measured by various techniques, including those that involve conventional strain gauges (based on electrical resistance) and those that involve more advanced strain gauges (based on optical fibers). A correlation is used to convert force-measurement data to the local flow angle. The use of fiber optics will enable the construction of a miniature FLAP, leading to the possibility of flow measurement in very small or confined regions. This may also enable the tufting of a surface with miniature FLAPs, capable of quantitative flow-angle measurements, similar to attaching yarn tufts for qualitative measurements. The prototype FLAP was a small, aerodynamically shaped, low-aspect-ratio fin about 2 in. (approximately equal to 5 cm) long, 1 in. (approximately equal to 2.5 cm) wide, and 0.125 in. (approximately equal to 0.3 cm) thick (see Figure 1). The prototype FLAP included simple electrical-resistance strain gauges for measuring forces. Four strain gauges were mounted on the FLAP; two on the upper surface and two on the lower surface. The gauges were connected to form a full Wheatstone bridge, configured as a bending bridge. In preparation for a flight test, the prototype FLAP was mounted on the airdata boom of a flight-test fixture (FTF) on the NASA Dryden F-15B flight research airplane.

Corda, Stephen; Vachon, M. Jake

2003-01-01

354

Comparison of Factors Associated With Occludable Angle Between American Caucasians and Ethnic Chinese  

PubMed Central

Purpose. To determine if factors associated with gonioscopy-determined occludable angle among American Caucasians are similar to those found in ethnic Chinese. Methods. This is a prospective cross-sectional study with 120 American Caucasian, 116 American Chinese, and 116 mainland Chinese subjects. All three groups were matched for sex and age (40–80 years). Gonioscopy was performed for each subject (occludable angles = posterior trabecular meshwork not visible for ?2 quadrants). Anterior segment optical coherence tomography and customized software was used to measure anterior segment biometry and iris parameters, including anterior chamber depth/width (ACD, ACW), lens vault (LV), and iris thickness/area/curvature. Results. In both Chinese and Caucasians, eyes with occludable angles had smaller ACD and ACW, and larger LV and iris curvature than eyes with open angles (all P < 0.005). Chinese eyes had smaller ACD and ACW than Caucasian eyes (both P < 0.01) in the occludable angle cohort. Iris characteristics did not differ significantly between Chinese and Caucasians in the occludable angle cohort. Based on multivariate logistic regression, gonioscopy-determined occludable angle was significantly associated with LV, iris area, and sex (all P < 0.03) in Chinese; and with LV, ACD, iris thickness, age, and sex (all P < 0.04) in Caucasians. Conclusions. Several factors associated with occludable angle differed between Caucasians and Chinese, suggesting potentially different mechanisms in occludable angle development in the two racial groups. This is the first study to demonstrate that lens vault is an important anterior segment optical coherence tomography parameter in the screening for angle closure in Caucasians. In addition, iris thickness was a significant predictor for occludable angles in Caucasians but was not in ethnic Chinese. PMID:24168992

Wang, Ye Elaine; Li, Yingjie; Wang, Dandan; He, Mingguang; Lin, Shan

2013-01-01

355

Immersion-Specific Defects of High-Receding-Angle Topcoat  

NASA Astrophysics Data System (ADS)

Dynamic receding contact angle (RCA) is a well-known parameter for estimating the degree of immersion-specific defects that have mainly circular and bridge shapes. In general, these defects decrease in number with increasing RCA of the topcoat (TC). However, we found the occurrence of circular defects despite using the TC with a large RCA. In this study, we analyzed the relationship between the physical properties of TC to reduce the number of defects. The result shows that the number of defects depends not only on a large RCA but also on a small amount of water uptake of TC. To understand well the degree of defects, the effective hysteresis (EH) is defined in terms of the RCA, the advancing contact angle (ACA) and the water absorption of TC. EH will be a useful way of explaining the circular defects. The characteristics of the defects are also discussed with a focus on the structure of the polymer attached to water.

Mamoru Terai,; Teruhiko Kumada,; Takuya Hagiwara,; Tetsuro Hanawa,; Tomoyuki Ando,; Takeshi Matsunobe,; Kazuyuki Okada,; Yuichi Muraji,; Kazuhiro Yoshikawa,; Naoki Man,

2010-06-01

356

Pitch-angle Scattering of Energetic Particles with Adiabatic Focusing  

NASA Astrophysics Data System (ADS)

Understanding turbulent transport of charged particles in magnetized plasmas often requires a model for the description of random variations in the particle's pitch angle. The Fokker-Planck coefficient of pitch-angle scattering, which is used to describe scattering parallel to the mean magnetic field, is therefore of central importance. Whereas quasi-linear theory assumes a homogeneous mean magnetic field, such a condition is often not fulfilled, especially for high-energy particles. Here, a new derivation of the quasi-linear approach is given that is based on the unperturbed orbit found for an adiabatically focused mean magnetic field. The results show that, depending on the ratio of the focusing length and the particle's Larmor radius, the Fokker-Planck coefficient is significantly modified but agrees with the classical expression in the limit of a homogeneous mean magnetic field.

Tautz, R. C.; Shalchi, A.; Dosch, A.

2014-10-01

357

Asymmetries in Silicon Microstrip Response Function and Lorentz Angle  

E-print Network

An experimental set up, dedicated to isolate an error present in the $\\eta$-algorithm, gave an unexpected result. The average of a center of gravity algorithm at orthogonal particle incidence turns out to be non zero. This non zero average signals an asymmetry in the response function of the strips, and introduces a further parameter in the corrections: the shift of the strip response center of gravity respect its geometrical position. A strategy to extract this parameter from a standard data set is discussed. Some simulations with various asymmetric response functions are explored for this test. The method is able to detect easily the asymmetry parameters introduced in the simulations. Its robustness is tested against angular rotations, and we see an almost linear variation with the angle. This simple property is used to simulate a determination of a Lorentz angle with and without the asymmetry of the response function.

Landi, Gregorio

2014-01-01

358

Precision measurement of the weak mixing angle in Møller scattering.  

PubMed

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) +/- 10(syst)] x 10(-9), leading to the determination of the weak mixing angle sin2(thetaW(eff) = 0.2397 +/- 0.0010(stat) +/- 0.0008(syst), evaluated at Q2 = 0.026 GeV2. Combining this result with the measurements of sin2(thetaW(eff) at the Z0 pole, the running of the weak mixing angle is observed with over 6sigma significance. The measurement sets constraints on new physics effects at the TeV scale. PMID:16196849

Anthony, P L; Arnold, R G; Arroyo, C; Bega, K; Biesiada, J; Bosted, P E; Bower, G; Cahoon, J; Carr, R; Cates, G D; Chen, J-P; Chudakov, E; Cooke, M; Decowski, P; Deur, A; Emam, W; Erickson, R; Fieguth, T; Field, C; Gao, J; Gary, M; Gustafsson, K; Hicks, R S; Holmes, R; Hughes, E W; Humensky, T B; Jones, G M; Kaufman, L J; Keller, L; Kolomensky, Yu G; Kumar, K S; LaViolette, P; Lhuillier, D; Lombard-Nelsen, R M; Marshall, Z; Mastromarino, P; McKeown, R D; Michaels, R; Niedziela, J; Olson, M; Paschke, K D; Peterson, G A; Pitthan, R; Relyea, D; Rock, S E; Saxton, O; Singh, J; Souder, P A; Szalata, Z M; Turner, J; Tweedie, B; Vacheret, A; Walz, D; Weber, T; Weisend, J; Woods, M; Younus, I

2005-08-19

359

Searching for the Neutrino Mixing Angle Theta-13 at Reactors  

E-print Network

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.

Maury Goodman

2007-06-04

360

The Turbulent Flow in Diffusers of Small Divergence Angle  

NASA Technical Reports Server (NTRS)

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.

Gourzhienko, G. A.

1947-01-01

361

Wide-angle breast tomosynthesis: initial comparative evaluation  

NASA Astrophysics Data System (ADS)

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.

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

2010-04-01

362

Tunable wide-angle plasmonic perfect absorber at visible frequencies  

NASA Astrophysics Data System (ADS)

We report a perfect absorber metallic hole array with wide-angle near unity absorbance in the visible regime. The periodicity of the structure enables excitation of surface-plasmon polaritons and results in a splitting of the absorbing peaks. An analytical formalism based on perturbation theory provides results in good agreement with experimental data and shows how the absorption peak can be tuned with hole geometry, periodicity, and material parameters. Being extendable to more complex hybrid structures, our result is important for the development of photon harvesting devices and thermal emitters.

Fang, Zheyu; Zhen, Yu-Rong; Fan, Linran; Zhu, Xing; Nordlander, Peter

2012-06-01

363

Seismic Slip on an Oblique Detachment Fault at Low Angles  

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

364

Spectroscopic refractometer for transparent and absorbing liquids by reflection of white light near the critical angle.  

PubMed

We propose and evaluate a spectroscopic refractometer device to measure the refractive index dispersion of transparent and absorbing solutions. The angle-dependent reflectivity of a white beam of light in an internal reflection configuration around the critical angle is spectrally analyzed. The refractive index in a wavelength range from 400 nm to 900 nm is obtained from the angle-reflectivity curve around the critical angle at each wavelength. The device does not use angle scanning mechanisms, decreasing considerably the complexity of the instrument in comparison to previous proposals. As a result, the measurements are obtained relatively fast. Nevertheless, a good experimental resolution in refractive index of about ?n ? 10(-4) at all the wavelengths is achieved in the case of transparent solutions. The calibration procedure of the device is discussed in detail. We also present measurements of the refractive index dispersion of rhodamine 6G-methanol solutions, which has a strong absorption band in the visible spectra. PMID:23206093

Sánchez-Pérez, C; García-Valenzuela, A

2012-11-01

365

Design of second order grating couplers to detect the angle and polarization of the laser beam  

NASA Astrophysics Data System (ADS)

On-chip laser beam tracking finds innumerable applications. Popularly adopted quadrant photodiodes can only detect laser beam's angle variation up to 0.2° reliably. In this paper, a novel angle detector is designed based on grating coupling. It consists of a grating layer on top of a silicon-on-insulator slab waveguide. The incident light is coupled into guided modes within the waveguide via the grating layer, and then, the incident light's angle can be determined by reading the outputs of light detectors within the waveguide. Performance of the laser angle detector in this paper is demonstrated by full-wave finite-difference-time-domain simulations. Numerical results show that, the detectable angle range can be adjusted by several design parameters and can reach [-4°, 4°]. The device structure in this paper can be straightforwardly extended to two-dimensional photonic crystal configurations.

Saha, Tapas Kumar; Lu, Mingyu; Zhao, Deyin; Ma, Zhenqiang; Zhou, Weidong

2012-03-01

366

A liquid crystal display with consistent moving image quality regardless of viewing angles  

NASA Astrophysics Data System (ADS)

This paper proposes a new overdrive (OD) technology to precisely compensate for the viewing angle dependent characteristics of LCDs. This paper reports that optical response of liquid crystal displays (LCDs) is considerably dependent on viewing angles for the first time. The new OD technology applies different OD look-up tables (LUTs) depending on the viewing angles. In addition, we combine a new OD technology with an eye tracker that is usually adopted for autostereoscopic 3D LCD systems. The application results show that a new OD technology improves the motion image quality perfectly regardless of viewing angles. We expect that our proposed method will definitely enable the LCD products to have consistent motion image quality regardless of viewing angles.

Kim, Jong-Man; Kim, Seung-Ryul; Kim, Jongbin; Kim, Minkoo; Lee, Seung-Woo

2014-08-01

367

Effects of flexibility on aerodynamic performance of delta wings with different sweep angles  

NASA Astrophysics Data System (ADS)

Force measurement and surface oil flow visualization experiments were conducted in a wind tunnel to investigate the effects of flexibility on aerodynamic performance of delta wings with different sweep angles. The experimental results indicate that the maximum lift coefficient is increased and the stall angle is delayed as the sweep angle increases for both rigid and flexible wings. It is also found that the maximum lift coefficients of the flexible wings with a sweep angle from 35° to 50° are higher than those of the rigid ones. The increment of the maximum lift coefficient in particular achieves 32.9% compared with the case without lift enhancement for the 40° flexible delta wing. Moreover, the surface oil flow visualization experiments show that the stall of the flexible wing of the moderate low sweep angle is accompanied by helical flow structure, while the vortex bursting appears on the corresponding rigid wing.

Liu, Yang; Zuo, Linxuan; Wang, Jinjun

2010-05-01

368

Effects of airfoil shape, thickness, camber, and angle of attack on calculated transonic unsteady airloads  

NASA Technical Reports Server (NTRS)

The effects of airfoil shape, thickness, camber, and mean angle of attack on transonic unsteady airloads were investigated as calculated by the transonic small-disturbance computer code XTRAN2L. Shape effects were investigated by examining the pressure distributions, shock locations, and unsteady airloads for three 10 percent thick airfoils. NACA 0010, NACA 64A010, and parabolic arc. Thickness effects were determined by studying a single airfoil shape with three different thicknesses: NACA 0008, NACA 0010, and NACA 0012. Angle of attack and camber effects were studied by including mean angle of attack or by adding a simple parabolic camber distribution to the originally symmetric airfoils. Comparisons of unsteady airloads for different airfoil configurations show similar results caused by variations in airfoil shape, thickness, camber, or mean angle of attack. Computer costs can be reduced by limiting the number of transonic unsteady aerodynamic calculations for small changes in airfoil geometry or angle of attack.

Batina, J. T.

1985-01-01

369

Kinematics of gait: new method for angle estimation based on accelerometers.  

PubMed

A new method for estimation of angles of leg segments and joints, which uses accelerometer arrays attached to body segments, is described. An array consists of two accelerometers mounted on a rigid rod. The absolute angle of each body segment was determined by band pass filtering of the differences between signals from parallel axes from two accelerometers mounted on the same rod. Joint angles were evaluated by subtracting absolute angles of the neighboring segments. This method eliminates the need for double integration as well as the drift typical for double integration. The efficiency of the algorithm is illustrated by experimental results involving healthy subjects who walked on a treadmill at various speeds, ranging between 0.15 m/s and 2.0 m/s. The validation was performed by comparing the estimated joint angles with the joint angles measured with flexible goniometers. The discrepancies were assessed by the differences between the two sets of data (obtained to be below 6 degrees) and by the Pearson correlation coefficient (greater than 0.97 for the knee angle and greater than 0.85 for the ankle angle). PMID:22346659

Djuri?-Jovi?i?, Milica D; Jovi?i?, Nenad S; Popovi?, Dejan B

2011-01-01

370

Comparison of Children with Joint Angles in Spastic Diplegia with Those of Normal Children  

PubMed Central

[Purpose] The purpose of this study was to compare joint angles between normal children and those with spastic diplegia using three-dimensional gait analysis. [Subjects and Methods] The study subjects were eight patients with spastic diplegia and eight normal children. Three-dimensional gait analysis was used for the survey. The measured gait variables were the joints of the lower extremity in the sagittal plane, frontal plane, and transverse planes and the maximum and minimum angles of their stance phase and swing phases. [Results] In the sagittal plane, the maximum angles of both the right and left pelvis and hip joint in the stance phase and swing phases were significantly greater for children with spastic diplegia than for normal children. In the stance phase of the right side of the hip joint, the maximum angles of the hip in the swing phase and the knee joint’s minimum angles in the stance phase differed significantly. In the transverse plane, there were a significant differences on the left side of the pelvis in the maximum angles in the swing and stance phases. There were also significant differences on the right side pelvis, in the maximum and minimum angles in the stance phase and minimum angles in the swing phase. [Conclusion] Children with spastic diplegia employ a different gait strategy and pattern from normal children. PMID:25276040

Kim, Chang Ju; Kim, Young Mi; Kim, Dong Dae

2014-01-01

371

The effect of pillar surface fraction and pillar height on contact angles using molecular dynamics  

NASA Astrophysics Data System (ADS)

Predicting hydrophobicity is very important in manufacturing products with self-cleaning properties. This study focuses on the effect of graphite surfaces with pillars of different surface fractions and heights on the contact angles of a nano-sized water droplet. This study used molecular dynamics simulations to investigate the hydrophobic properties of water droplets on the nano-scale. The contact angles were calculated and averaged over time for each case. Results showed the droplets in either the Wenzel state or the Cassie state. In general, as the pillar height increases the static contact angle increases to a certain point when the pillar height no longer has a significant effect on the contact angle. Over all, the smaller the pillar surface fraction the larger the change in the contact angle as the pillar height increased. As pillar surface fractions decreased from 36%, simulated contact angles undershot Cassie predictions at increasing amounts due to part of the water droplet sagging below the pillar tops. Graphite displayed anisotropic characteristics due to its layered structure which caused the contact angles to increase as surface roughness increased even though its Young contact angle was less than 90 degrees.

Ambrosia, Matthew Stanley; Ha, Man Yeong; Balachandar, S.

2013-10-01

372

Shuttle Program. Euler angles, quaternions, and transformation matrices working relationships  

NASA Technical Reports Server (NTRS)

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.

Henderson, D. M.

1977-01-01

373

Angle of arrival and irradiance statistics of laser beams in turbulence  

NASA Astrophysics Data System (ADS)

Measurement of the local angle of arrival in a laser beam traveling in turbulence is achieved by frequency demodulating the heterodyne signal derived from the interference of a probe and a reference beam. The resulting data are then used to demonstrate that the statistical correlation between the angle of arrival and the irradiance is weak and that the random angle of arrival is normally distributed. These results constitute a direct confirmation of two fundamental assumptions of the theoretical model of propagation in turbulence previously developed at the Defence Research Establishment Valcartier (DREV).

Bissonnette, L.; Cote, R.

1981-07-01

374

A nonlinear theory of cosmic ray pitch angle diffusion in homogeneous magnetostatic turbulence  

NASA Technical Reports Server (NTRS)

A plasma strong turbulence, weak coupling, theory is applied to the problem of cosmic ray pitch angle scattering in magnetostatic turbulence. The theory used is a rigorous generalization of Weinstock's resonance-broadening theory and contains no ad hoc approximations. A detailed calculation is presented for a model of slab turbulence with an exponential correlation function. The results agree well with numerical simulations. The rigidity dependence of the pitch angle scattering coefficient differs from that found by previous researchers. The differences result from an inadequate treatment of particle trajectories near 90 deg pitch angle in earlier work.

Goldstein, M. L.

1975-01-01

375

A nonlinear theory of cosmic-ray pitch-angle diffusion in homogeneous magnetostatic turbulence  

NASA Technical Reports Server (NTRS)

A plasma strong turbulence, weak coupling, theory is applied to the problem of cosmic-ray pitch-angle scattering in magnetostatic turbulence. The theory used is a rigorous generalization of Weinstock's 'resonance broadening' theory and contains no ad hoc approximations. A detailed calculation is presented for a model of 'slab' turbulence with an exponential correlation function. The results agree well with numerical simulations. The rigidity dependence of the pitch-angle scattering coefficient differs from that found by previous researchers. The differences result from an inadequate treatment of particle trajectories near 90 deg pitch angle in earlier work.

Goldstein, M. L.

1976-01-01

376

Gantry-angle resolved VMAT pretreatment verification using EPID image prediction  

SciTech Connect

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.

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

377

Sun angle, view angle, and background effects on spectral response of simulated balsam fir canopies  

NASA Technical Reports Server (NTRS)

An experiment is described that examines the effects of solar zenith angle and background reflectance on the composite scene reflectance of small balsam fir (Abies balsamea (L.) Mill.) arranged in different densities. In this study, the shape, density, and, consequently, the needle area index and phytomass of the canopies, as well as the background reflectance, were controlled. The effects of sun angle, view angle, and background reflectance on the multispectral response of small balsam fir trees were significant. Regression models relating spectral vegetation indices (i.e., normalized difference (ND) and greenness (GR) to phytomass) showed very poor relationships for balsam fir canopies with a grass background. However, strong linear relationships were found for ND and GR with phytomass for a background that simulated the reflectance of snow. Changing solar zenith angle significantly affected the models relating ND to phytomass for the snow background, but was not significant in the model relating GR to phytomass for the snow background

Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.

1986-01-01

378

Sparse regularization in limited angle tomography  

E-print Network

We investigate the reconstruction problem of limited angle tomography. Such problems arise naturally in applications like digital breast tomosynthesis, dental tomography, electron microscopy etc. Since the acquired tomographic data is highly incomplete, the reconstruction problem is severely ill-posed and the traditional reconstruction methods, such as filtered backprojection (FBP), do not perform well in such situations. To stabilize the reconstruction procedure additional prior knowledge about the unknown object has to be integrated into the reconstruction process. In this work, we propose the use of the sparse regularization technique in combination with curvelets. We argue that this technique gives rise to an edge-preserving reconstruction. Moreover, we show that the dimension of the problem can be significantly reduced in the curvelet domain. To this end, we give a characterization of the kernel of limited angle Radon transform in terms of curvelets and derive a characterization of solutions obtained thr...

Frikel, Jürgen

2011-01-01

379

Branes at Angles from DBI Action  

Microsoft Academic Search

In this paper we investigate about several configurations of two intersecting branes at arbitrary angles. We choose the viewpoint of a brane source and a brane probe and use the low-energy dynamics of p-branes. For each p-brane this dynamics is governed by a generic DBI action including a WZ term, which couples to the SUGRA background of the other brane.

Reza Abbaspur

1999-01-01

380

Wide angle zoom for the Space Shuttle  

NASA Astrophysics Data System (ADS)

In order to pilot and visually monitor the Canadarm operating on the Shuttle, a zoom lens with a minimum wide angle of 98 deg field of view was needed. The design of the chosen solution is presented. There are 22 lenses arranged in 4 groups allowing mechanical compensation. The range of focal lengths is 8.2 to 25 mm; the aperture is f/3.6. The weight is 1.6 kilos.

Angenieux, J.; Debize, J.; Masson, A.

1983-01-01

381

Prediction of lower extremities' movement by angle-angle diagrams and neural networks.  

PubMed

In contemporary science, the analysis of human walking is extensively used. The prediction of leg motion, as well as rehabilitation, can be usable for orthosis and prosthesis programing. Our work is focused on predicting of human walking by angle-angle diagrams, also called cyclograms. The applications of cyclograms in conjunction with artificial intelligence offers wide area of applications in medicine. But until now, this approach has not been studied or applied in practice. PMID:22097908

Kutilek, Patrik; Farkasova, Barbora

2011-01-01

382

A simple accurate algorithm for the critical angle refractometer  

NASA Astrophysics Data System (ADS)

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.

Ye, Junwei; Tao, Luo; Yang, Kecheng; Xia, Min; Li, Wei; Guo, Wenping; Liu, Hao

2013-09-01

383

Bank Angle of a V-Type 12-Cylinder Engine  

NASA Astrophysics Data System (ADS)

As the automobile engine advances towards higher performance and higher power, the increase in displacement and the number of cylinders in the engine has led to larger engines. As a result, the need for rigidity countermeasures and reductions in size and weight have brought about the switch from in-line type engines to V-type engines. Currently, most of the V-type automobile engines produced have six or eight cylinders, and some large passenger cars produced in Europe and America have V-type engines with 10 or 12 cylinders. The bank angles of engines in these passenger are almost fixed based on the cylinder number. Therefore, the form of the V-type engine is limited according to the number of cylinders. The present study examines the bank angle of a V-12 engine by performing a detailed analysis of the relationship between the cylinder arrangement and the exciting moment. The goal of the present study is to find a bank angle that has as of yet not been applied to the V-type engine so that the layouts of the absorption and exhaust systems, as well as the attached apparatuses, can be reconfigured.

Ito, Norio; Nakagawa, Akihito; Kitamura, Ryuji

384

Small Angle X-Ray Scattering Detector  

DOEpatents

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.

Hessler, Jan P. (Downers Grove, IL)

2004-06-15

385

Angles-Let's treat them squarely  

NASA Astrophysics Data System (ADS)

We suggest a self-consistent treatment of the dimensions and units of the geometric quantity "angle." The method regards "angle" as a fundamental dimensional physical quantity, on a par with length, mass, time, etc. All units (whether angular or otherwise) are treated on an equal footing and balance out correctly; in particular, "radian" units need never be spuriously inserted or deleted. The method could find application in algebraic and calculus symbolic manipulation computer programs to correctly process units of physical quantities. The technique necessitates a minor modification of the relation "s=R?" and its consequences, rather than any modification of the units of other physical quantities (such as moment arms) as previously suggested by others. We make several important clarifying distinctions: (a) ? [SI: rad?s-1] for rotational motion (as in ?=?t) versus ? [SI: s-1] for simple harmonic motion [as in x=xm cos(?t)], (b) geometric trigonometric functions whose arguments are angles [SI: rad] versus mathematical trigonometric functions whose arguments are pure numbers, (c) simple harmonic motion versus uniform circular motion in the reference circle analogy.

Brownstein, K. R.

1997-07-01

386

Analysis of gonial angle in relation to age, gender, and dentition status by radiological and anthropometric methods  

PubMed Central

Background: With development and function, the mandibular angle has shown changes in size and shape. A variation in mandibular angle with age, gender, and even the dental status has been observed, which is supported by radiographic and anthropometric studies. Aims: The aim of this study were to evaluate relationship between complete loss of teeth and changes in the gonial angle; the study further intends to evaluate any variation in gonial angle with age and gender. The study intends to assess the reliability and accuracy of age and gender determination using gonial angle as a parameter. Materials and Methods: A total of 185 subjects (91 males; 89 females) were included in the study and were divided into five groups on the basis of the chronological age. Physico-forensic anthropometry and lateral cephalometric methods were used to record the gonial angle. Results: The present study shows a definite decrease in the gonial angle with advancing age, but the intergroup analysis does not follow a significant pattern. The study showed no correlation of gonial angle with gender. However, the study observed a 6° increase in gonial angle for edentulous subjects. Conclusion: Gonial angle has been used as an adjuvant forensic parameter, but its reliability is questionable, as the mandible does not follow one characteristic pattern. Gonial angle does show changes with dentition status, which may be attributed to physiologic function of the mandible. However, when evidence is scanty, it can be used to direct the investigation. PMID:23087579

Upadhyay, Ram Ballabh; Upadhyay, Juhi; Agrawal, Pankaj; Rao, Nirmala N

2012-01-01

387

Laser Tracker Calibration - Testing the Angle Measurement System -  

SciTech Connect

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.

Gassner, Georg; Ruland, Robert; /SLAC

2008-12-05

388

A high angle of attack inviscid shuttle orbiter computation  

NASA Technical Reports Server (NTRS)

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.

Kleb, William L.; Weilmuenster, K. James

1992-01-01

389

Maintaining the FGS3 optical field angle distortion calibration  

NASA Technical Reports Server (NTRS)

To date four OFAD (Optical Field Angle Distortion) calibrations have been performed on FGS3 in M35 and analyzed by the Astrometry Science Team. Two have been performed since the last HST (Hubble Space Telescope) Calibration Workshop. The ongoing Long Term Stability Tests have also been analyzed and incorporated into the calibration. A lateral color calibration has been derived from calibration and science data. Descriptions of these tests and the results of our analysis of the resulting data are given. The astrometric science supported by these calibrations is briefly reviewed.

McArthur, B.; Benedict, G. F.; Jefferys, W. H.; Nelan, E.

1997-01-01

390

The Change in Knee Angle during the Gait by Applying Elastic Tape to the Skin.  

PubMed

[Purpose] The aim of this study was to verify how the application of elastic tape to the anterior surface of the thigh changes the knee angle pattern during gait. [Subjects] The subjects were 10 people who showed an abnormal knee angle change pattern during usual walking. They did not show the so-called double knee action. [Methods] Subjects were asked to walk as usual, and then to walk with elastic tape attached to the anterior surface of the thigh. The knee angle was measured during gait with an electronic goniometer. We graphed the temporal changes of the knee angle and compared them with the normal gait pattern. [Results] The knee angle gait pattern of six of the 10 subjects improved after application of the tape and became like a normal gait pattern. The changes in the knee angle resulted from a stimulus via the skin, rather than voluntary muscular adjustment, suggesting that the changes may have originated due to differences in reflexive tensile strength. [Conclusion] In normal speed gait, it is suggested that the knee angle was altered such that it exhibited a normal pattern by applying elastic tape to the anterior surface of the thigh. We suspect that application of the elastic tape may change the muscle tonus. PMID:25140100

Yamamoto, Hiroyuki

2014-07-01

391

The Change in Knee Angle during the Gait by Applying Elastic Tape to the Skin  

PubMed Central

[Purpose] The aim of this study was to verify how the application of elastic tape to the anterior surface of the thigh changes the knee angle pattern during gait. [Subjects] The subjects were 10 people who showed an abnormal knee angle change pattern during usual walking. They did not show the so-called double knee action. [Methods] Subjects were asked to walk as usual, and then to walk with elastic tape attached to the anterior surface of the thigh. The knee angle was measured during gait with an electronic goniometer. We graphed the temporal changes of the knee angle and compared them with the normal gait pattern. [Results] The knee angle gait pattern of six of the 10 subjects improved after application of the tape and became like a normal gait pattern. The changes in the knee angle resulted from a stimulus via the skin, rather than voluntary muscular adjustment, suggesting that the changes may have originated due to differences in reflexive tensile strength. [Conclusion] In normal speed gait, it is suggested that the knee angle was altered such that it exhibited a normal pattern by applying elastic tape to the anterior surface of the thigh. We suspect that application of the elastic tape may change the muscle tonus. PMID:25140100

Yamamoto, Hiroyuki

2014-01-01

392

Ray-tracing studies for a whole-viewing-angle retroreflector  

SciTech Connect

The APS Survey and Alignment team uses LEICA laser trackers for the majority of their alignment tasks. These instruments utilize several different retroreflectors for tracking the path of the laser interferometer. Currently in use are open-air corner cubes with an acceptance angle of {+-}20{degree}, corner cube prisms with an acceptance angle of {+-}50{degree}, and a Cat's eye with an acceptance angle of {+-}60{degree}. Best measurement results can be achieved by using an open-air corner cube that eliminates the need for the laser beam to travel through a different medium before it returns to the instrument detector. However, the trade off is a small acceptance angle. In order to overcome the limitations of the small acceptance angles, Takatsuji et al. has proposed the creation of a full-viewing-angle retroreflector. Based on the notion that the radius R{sub 1} of a common Cat's eye is proportional to R{sub 2}, one can write: R{sub 1} = (n {minus} 1)R{sub 2}. In the case that n, the refractive index of glass, equals 2, the radii R{sub 1} and R{sub 2} are identical, and one can create a solid sphere Cat's eye. This design has the advantages that no adhesives are used to bond the two hemispheres together, misalignments between the hemispheres are not an issue, and most importantly, larger acceptance angles are possible. This paper shows the results of their ray tracing calculations characterizing the geometrical optics.

Yang, B.; Friedsam, H.

2000-02-02

393

Comparing the range of ? and ? angles in 6-17-year-old children of Isfahan with normal occlusion  

PubMed Central

Background: Linear and angular measurements such as A point, nasion, B point (ANB) angle and Wits appraisal index are not accurate enough to evaluate sagittal relationship of the jaws. The aim of this study was to evaluate and compare the range of ? and ? angles in 6-17-year-old children of Isfahan, having normal occlusion. Materials and Methods: This was an analytical descriptive study. For this study, 235 cephalometric radiographs of patients who didn’t receive orthodontics treatments and based on 13 indexes had normal occlusion, were selected. After tracing of cephalograms, ANB angle, Wits appraisal index, ? angle (resulted from the intersection of AB line and perpendicular line from point A to mandibular plane) and ? angle (resulted from the intersection of AB line and perpendicular line from point A on CB line) were measured. Data was analyzed by t-test, ANOVA and Pierson-Spearman correlation coefficient (P < 0.05). Results: Mean value of ? and ? angles were 17.34 ± 3.47 and 31.7 ± 3.31 and ranged from 8-27 to 21.5-39 respectively. According to t-test, there was a significant difference between two sex groups for ? angle (P = 0.02); however, it was not significant for ? angle. According to Spearman correlation coefficient, there was no significant difference between age and ? angle; however, ? angle was directly and significantly related to age (r = 0.435). There was significant and reverse relationship between ? and ? angles with ANB angle and Wits appraisal index. Conclusion: ? and ? angles are reliable and can be used to evaluate the anterior-posterior relationship of the jaws. PMID:24688558

Sadeghian, Saeed; Hajiahmadi, Maryam; Khorrami, Ladan; Moshkelgosha, Hadi

2014-01-01

394

Two Years of Digital Terrain Model Production Using the Lunar Reconnaissance Orbiter Narrow Angle Camera  

NASA Astrophysics Data System (ADS)

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.

Burns, K.; Robinson, M. S.; Speyerer, E.; LROC Science Team

2011-12-01

395

Effect of Anteromedial Portal Entrance Drilling Angle during Anterior Cruciate Ligament Reconstruction: A Three-Dimensional Computer Simulation  

PubMed Central

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

Moon, Dong Kyu; Yoon, Chul Ho; Park, Jin Seung; Kang, Bun Jung; Cho, Seong Hee; Jo, Ho Seung

2014-01-01

396

Model of pitch angle diffusion in the Earth's magnetosphere  

NASA Astrophysics Data System (ADS)

The mathematical model of pitch angle diffusion in the magnetosphere which allows to compute theoretically density of phase space or pitch angle distribution of the charged particles is offered. On concrete example of pitch angle distribution evolution during the 21 - 22 October 1999 geomagnetic storm potential opportunities of offered model of pitch angle diffusion on the nightside of the Earth's magnetosphere are shown. The good consent of the model pitch angle distributions with the storm-time butterfly pitch angle distributions of protons observed by the Polar satellite is received.

Smolin, Sergey

397

View angle effects in the radiometric measurement of plant canopy temperatures  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

398

Performance analysis of first iteration koch curve fractal log periodic antenna of varying flare angles  

NASA Astrophysics Data System (ADS)

Miniaturization has always been a crucial challenge in the field of antenna engineering. In the recent past a number of researchers have shown that fractal geometry have potential to design smaller, broad band and multi band antennas. In this proposed work performances of log periodic fractal antennas of different flare angles have been investigated. Simulation results show that fractal log periodic antenna gives better performance in terms of gain, return loss and directivity. Performance of log periodic fractal antenna has also been investigated for flare angles 30°, 45°, 60°, 70° and 80°. In this proposed work fractal antenna gives best performance with 60° flare angle.

Singh, Ashutosh K.; Kabeer, Reneez A.; Ali, Z.; Singh, V. K.; Shukla, M.

2013-03-01

399

Mechanical basis for slip along low-angle normal faults  

NASA Astrophysics Data System (ADS)

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.

Lecomte, E.; Le Pourhiet, L.; Lacombe, O.

2012-04-01

400

Class 2 Levers: Force Input Angles  

NSDL National Science Digital Library

This interactive presentation, created by authors James Bourassa and John Rosz, explains how the input of force reacts with lever systems. The authors address the physics behind levers, and how when proper angles are used in design the effective force increases greatly. The format of the lesson is akin to an animated PowerPoint presentation. Each slide is filled with flash animations lined with the mathematical formulas behind the physics of the problem. Following the lesson is made easier because of the thoroughness of each individual slide. This is a great resource for either a student or educator interested in either electromechanical engineering or just simply physics.

Bourassa, James; Rosz, John

2011-03-22

401

Quantum Geometry Phenomenology: Angle and Semiclassical States  

E-print Network

The phenomenology for the deep spatial geometry of loop quantum gravity is discussed. In the context of a simple model of an atom of space, it is shown how purely combinatorial structures can affect observations. The angle operator is used to develop a model of angular corrections to local, continuum flat-space 3-geometries. The physical effects involve neither breaking of local Lorentz invariance nor Planck scale suppression, but rather reply on only the combinatorics of SU(2) recouping theory. Bhabha scattering is discussed as an example of how the effects might be observationally accessible.

Seth A. Major

2011-12-19

402

Junctional angle of a bihanded helix  

NASA Astrophysics Data System (ADS)

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.

Yang, Jing; Wolgemuth, Charles W.; Huber, Greg

2014-10-01

403

{l_angle}100{r_angle} Burgers vector in single phase {gamma}{prime} material verified by image simulation  

SciTech Connect

The deformation mechanisms of Ni{sub 3}Al, an ordered L1{sub 2} or {gamma}{prime} phase, is under intense research since Westbrook showed the increase of its hardness with temperature in 1957. The super dislocations of this ordered phase normally have Burgers vectors {rvec b} = a {l_angle}110{r_angle}, disassociated in either two a/2 {l_angle}110{r_angle} or two {rvec b} = a/3 {l_angle}112{r_angle}, depending on deformation temperature and rate. Recent observations in [111] oriented {gamma}{prime} specimens suggest that additional dislocations with the shorter Burgers vector {rvec b} = a {l_angle}100{r_angle} might be active. Dislocations with {rvec b} = a {l_angle}110{r_angle} on cube glide planes have a Schmidt factor of 0.47 and on octahedral planes of 0.27. Dislocations with {rvec b} = a {l_angle}100{r_angle} have a Schmidt factor of 0.47 for {l_brace}110{r_brace} glide planes and 0.33 for cube glide planes. The a {l_angle}100{r_angle} Burgers vector is the shortest of all complete dislocations of the L1{sub 2} structure and creates no planar fault like antiphase boundaries or stacking faults. Due to the [111] oriented stress axis, which is used in this contribution, plastic deformation by a {l_angle}100{r_angle} dislocations as well as cube glide planes for {l_angle}110{r_angle} dislocations is encouraged. These dislocations could be reaction products, but will soon after contribute to deformation.

Link, T.; Knobloch, C. [Technische Univ. Berlin (Germany)] [Technische Univ. Berlin (Germany); Glatzel, U. [Friedrich-Schiller-Univ. Jena (Germany). Metallische Werkstoffe] [Friedrich-Schiller-Univ. Jena (Germany). Metallische Werkstoffe

1998-12-04

404

Small angle neutron scattering investigation of microporosity in marbles  

NASA Astrophysics Data System (ADS)

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.

Coppola, R.; Lapp, A.; Magnani, M.; Valli, M.

405

High tip angle approximation based on a modified Bloch-Riccati equation.  

PubMed

When designing a radio-frequency pulse to produce a desired dependence of magnetization on frequency or position, the small flip angle approximation is often used as a first step, and a Fourier relation between pulse and transverse magnetization is then invoked. However, common intuition often leads to linear scaling of the resulting pulse so as to produce a larger flip angle than the approximation warrants--with surprisingly good results. Starting from a modified version of the Bloch-Riccati equation, a differential equation in the flip angle itself, rather than in magnetization, is derived. As this equation has a substantial linear component that is an instance of Fourier's equation, the intuitive approach is seen to be justified. Examples of the accuracy of this higher tip angle approximation are given for both constant- and variable-phase pulses. PMID:22139869

Boulant, Nicolas; Hoult, David I

2012-02-01

406

Small-angle approximation to the transfer of narrow laser beams in anisotropic scattering media  

NASA Technical Reports Server (NTRS)

The broadening and the signal power detected of a laser beam traversing an anisotropic scattering medium were examined using the small-angle approximation to the radiative transfer equation in which photons suffering large-angle deflections are neglected. To obtain tractable answers, simple Gaussian and non-Gaussian functions for the scattering phase functions are assumed. Two other approximate approaches employed in the field to further simplify the small-angle approximation solutions are described, and the results obtained by one of them are compared with those obtained using small-angle approximation. An exact method for obtaining the contribution of each higher order scattering to the radiance field is examined but no results are presented.

Box, M. A.; Deepak, A.

1981-01-01

407

Measurement of two-dimensional small angle deviation with a prism interferometer  

SciTech Connect

A new technique for the measurement of two-dimensional small angular deviation is presented. A compound prism, which effectively produces a combination of two right-angled prisms in orthogonal directions, and plane reference surfaces have been utilized for the measurement of the orthogonal components of the angular tilt of an incident plane wavefront. Each orthogonal component of the angular tilt is separately measured from the angular rotation of the resultant wedge fringes between two plane wavefronts generated due to splitting of the incident plane wavefront by the corresponding set of right-angled prism and plane reference surface. The technique is shown to have high sensitivity for the measurement of small angle deviation. A monolithic prism interferometer, which is practically insensitive to vibration, is also proposed. Results obtained for the measurement of a known tilt angle are presented.

Chatterjee, Sanjib; Kumar, Y. Pavan

2008-09-20

408

Influence of the Angle of Attack on the Aerothermodynamics of the Mars Science Laboratory  

NASA Technical Reports Server (NTRS)

An investigation of the effects of the incidence angle on the aerothermodynamic environments of the Mars Science Laboratory has been conducted. Flight conditions of peak heating, peak deceleration and chute deploy are selected and the effects of the angle of attack on the aerodynamics and aerothermodynamics are analyzed. The investigation found that static aerodynamics are well behaved within the considered range of incidence angles. Leeside laminar and turbulent computed heating rates decrease with incidence, despite the increase in the leeside running length. Stagnation point was found to stay on the conical flank at all angles of attack, and this is linked to the rapid flow expansion around the shoulder. Hypersonic lift to drag ratio is limited by the heating rates in the region of the windside shoulder. The effects of the high angle of incidence on the dynamic aero at low Mach remains to be determined. Influence of the angle of attack on the smooth-wall transition parameter indicates, that higher angle of attack flight may result in delayed turbulence onset, however, a coupled analysis, involving flight trajectory simulation is necessary.

Dyakonov, Artem A.; Edquist, Karl T.; Schoenenberger, Mark

2006-01-01

409

Flow visualization for different port angles of a pulsatile ventricular assist device.  

PubMed

The "washout effect" inside a blood pump may depend in part on the configuration of the blood pump, including its "port angle." The port angle, which is primarily decided based on anatomical considerations, may also be important from the rheological viewpoint. In our department, a next-generation diaphragm-type blood pump is being developed. In this study, we examined the influence of the port angle on flow conditions inside our new blood pump. Acrylic resin mock pumps with three different port angles (0°, 30°, and 45°) were prepared for flow visualization. Mechanical monoleaflet valves were mounted on the inlet and outlet ports of the mock pumps. Flow conditions within the mock pumps were visualized by means of particle image velocimetry during a half stroke. As a result, a high flow velocity region was seen along the main circular flow from the inlet to the outlet port. This circular flow was almost uniform and parallel to the plane of the diaphragm-housing junction (DhJ) when viewed from the inlet and outlet sides. Moreover, the proportion of high flow velocity vectors in the plane in the vicinity of the DhJ decreased as the degree of the port angle increased. In conclusion, we found that the flow behavior in the plane in the vicinity of the DhJ changed with the port angle, and that a port angle of 0° may be suitable for our diaphragm-type blood pump in view of the washout effect. PMID:22038496

Akagawa, Eiki; Lee, Hwansung; Tatsumi, Eisuke; Homma, Akihiko; Tsukiya, Tomonori; Taenaka, Yoshiyuki

2012-06-01

410

PITCH ANGLE RESTRICTIONS IN LATE-TYPE SPIRAL GALAXIES BASED ON CHAOTIC AND ORDERED ORBITAL BEHAVIOR  

SciTech Connect

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 .

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

411

Joint torque and angle estimation by using ultrasonic muscle activity sensor  

NASA Astrophysics Data System (ADS)

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.

Tsutsui, Yoichiro; Tanaka, Takayuki; Kaneko, Shun'ichi; Feng, Maria Q.

2005-12-01

412

WIDE-ANGLE, NARROW-ANGLE, AND IMAGING BASELINES OF OPTICAL LONG-BASELINE INTERFEROMETERS  

SciTech Connect

For optical interferometers, the baseline is typically defined as the vector joining two perfectly identical telescopes. However, when the telescopes are naturally different or when the requirements on the baseline vector challenge the telescope perfection, the baseline definition depends on how the interferometer is used. This is where the notions of wide-angle, narrow-angle, and imaging baselines come into play. This article explores this variety of baselines, with the purpose of presenting a coherent set of definitions, describing how they relate to each other, and suggesting baseline metrology requirements. Ultimately, this work aims at supporting upcoming long-baseline optical interferometers with narrow-angle astrometry and phase-referenced imaging capabilities at the microarcsecond level.

Woillez, J. [W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, HI 96743 (United States)] [W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, HI 96743 (United States); Lacour, S., E-mail: jwoillez@keck.hawaii.edu, E-mail: sylvestre.lacour@obspm.fr [Observatoire de Paris, Place Jules Janssen, F-92195 Meudon (France)

2013-02-10

413

Effects of dipole tilt angle on geomagnetic activity  

NASA Astrophysics Data System (ADS)

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.

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

2009-09-01

414

Calculating Flow-Angle Deviation in Rotary Pumps  

NASA Technical Reports Server (NTRS)

New mathematical formula calculates difference between angle of impeller blade and angle of flow. Formula used for inducers of mixed-flow pumps. With formula, calculations made more quickly and accurately than previously available formulas.

Meng, S. Y.; Furst, R. B.

1986-01-01

415

Flattening fixed-angle chains is strongly NP-hard  

E-print Network

Planar configurations of fixed-angle chains and trees are well studied in polymer science and molecular biology. We prove that it is strongly NP-hard to decide whether a polygonal chain with fixed edge lengths and angles ...

Demaine, Erik D.

416

Alternative IR geometries for TESLA with a small crossing angle  

E-print Network

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.

R. Appleby; D. Angal-Kalinin; P. Bambade; B. Mouton; O. Napoly; J. Payet; the TESLA Collaboration

2004-12-09

417

Fibrotic nodule arising from the cerebellopontine angle.  

PubMed

The authors present an extremely rare case of a fibrotic nodule arising from the cerebellopontine (CP) angle. A 57-year-old male had suffered from hearing disturbance and tinnitus for several years. Computed tomography revealed a high-density mass in the left CP angle with little enhancement after intravenous administration of contrast media. Magnetic resonance imaging (MRI) showed a very hypointense mass on T2-weighted imaging. T1-weighted MRI with gadolinium revealed very faint, delayed enhancement of the tumor. The pat