Note: This page contains sample records for the topic nadir angle results from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Retrieval of trace gas vertical columns from SCIAMACHY/ENVISAT near-infrared nadir spectra: first preliminary results  

NASA Astrophysics Data System (ADS)

The European environmental satellite ENVISAT was successfully launched on 1st of March 2002. The UV/visible/near-infrared grating spectrometer SCIAMACHY is part of ENVISAT's atmospheric science payload. SCIAMACHY observes the atmosphere in nadir, limb, and solar and lunar occultation viewing geometries with moderate spectral resolution (0.2-1.5 nm). At the University of Bremen a modified DOAS algorithm (WFM-DOAS) is being developed primarily for the retrieval of CH 4, CO, CO 2, H 2O, N 2O, and O 2 total column amounts from ratios of SCIAMACHY nadir radiance and solar irradiance spectra in the near-infrared and visible spectral regions. First preliminary results concerning this activity are presented. SCIAMACHY is currently (September 2002) in its commissioning phase and only preliminary, i.e., not yet fully calibrated, Level 1 data products are available, generated mainly for initial Level 0 to 1 processing verification purposes. A method aimed at improving the retrieval in case of systematic artifacts resulting from, e.g., residual calibration errors, is presented. This study focuses on methane vertical column retrieval using channel 8 (2260-2385 nm). One of the major scientific objectives of the SCIAMACHY methane measurements is to derive information on methane (surface) sources and sinks. Such an application requires a relative radiometric accuracy close to the signal-to-noise performance of the instrument (S/N ˜50-100 in channel 8 for albedo 0.1 and solar zenith angle 60°) and an accurate and fast retrieval algorithm. This study presents first steps undertaken to reach this ambitious goal, focusing on the retrieval algorithm.

Buchwitz, M.; Noël, S.; Bramstedt, K.; Rozanov, V. V.; Eisinger, M.; Bovensmann, H.; Tsvetkova, S.; Burrows, J. P.

2004-01-01

2

Reflectance anisotropy for nadir observations of coniferous forest canopies  

SciTech Connect

Nadir-viewed reflectances from forest canopies in four spectral bands, centered at 485 nm, 654 nm, 841 nm, and 1,676 nm were measured at different sun angles. Reflectances were measured made from a helicopter ca. 10 km NE of Stockholm, Sweden, over mature and young stands of Scotch pine (Pinus sylvestris) and Norway spruce (Picea abies). The results show a significant increase in nadir reflectance with decreasing solar zenith angle. On the average, reflectance factors increased by 1--2% for each degree of decreasing solar zenith angle. Band ratios showed that there is a disproportional reflectance response in several of the spectral bands at varying zenith angles, differently expressed according to stand type and age. Within the solar zenith angle interval 30--70[degree], canopy reflectance was expressed as linear functions for each spectral band. These functions were used to calculate factors for reflectance standardization. Nomograms, containing reflectance correction factors for mature spruce stands, are presented. These can be directly applied in time-series analysis of multitemporal spectral data.

Syren, P. (Stockholm Univ. (Sweden). Lab. of Remote Sensing)

1994-07-01

3

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

Microsoft Academic Search

Scanning single-frequency radiometers have been used in the past to measure the thickness of oil layers. The proposed radiometer includes two improvements to the present systems. One is the use of the pushbroom concept where the scanning antenna is replaced by a multifeed antenna and the other improvement is the observation of the oil spill at two different angles to

D. Salzer; W. Birkmayer; G. Braun

1987-01-01

4

Glancing angle deposition: recent research results  

NASA Astrophysics Data System (ADS)

Unique thin film microstructures have been fabricated with the Glancing Angle Deposition (GLAD) technique. These porous, thin films can be engineered with a variety of different morphologies to sub-micron dimensions, including helical, post, and chevron or zigzag microstructures. This paper reports some recent results in study and application of films deposited using GLAD, namely: the use of low pressure, long throw sputtering to produce porous titanium films; deposition of porous, structured ZrO2 films for use as thermal barriers; and measurement of the mechanical response of chiral or `microspring' thin films.

Brett, Michael J.; Seto, Mary W.; Sit, Jeremy C.; Harris, K. D.; Vick, Doug; Robbie, Kevin

1999-06-01

5

Recent Results on the CKM Angle Alpha  

SciTech Connect

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

Mihalyi, A.; /Wisconsin U., Madison

2005-10-18

6

OSRMS: The DREP Near-Nadir Scatterometer.  

National Technical Information Service (NTIS)

The ocean surface roughness measurement system (OSRMS) is a near-nadir directed infrared (IR) scatterometer specially constructed for and operated by the Defence Research Establishment Pacific (DREP). It has been used to measure ocean surface parameters a...

L. C. Rempel B. A. Hughes S. J. Hughes

1988-01-01

7

Angles  

NSDL National Science Digital Library

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

Edkins, Jo

2007-01-01

8

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

9

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

10

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

11

Results from the G0 forward angle measurement  

SciTech Connect

The results from the G0 forward angle experiment are reported in this talk. The parity-violating asymmetry of elastic e-p scattering has been measured within the range of the four-momentum transfer (Q2) from 0.12 to 1.0 (GeV/c)2, which yields linear combinations of the strange electric and magnetic form factors of the nucleon, G{sub E}{sup s} + etaG{sub M}{sup s}, in the same Q2 range. The G0 results, combined with the measurements from other experiments, indicate that G{sub E}{sup s} and G{sub M}{sup s} are both likely non-zero.

J. Liu

2006-07-01

12

Retrieval of tropospheric NO2 columns from SCIAMACHY combining measurements from limb and nadir geometries  

NASA Astrophysics Data System (ADS)

Satellite measurements of atmospheric trace gases have proved to be an invaluable tool for monitoring the Earth system. When these measurements are to be used for assessing tropospheric emissions and pollution, as for example in the case of nadir measurements of nitrogen dioxide (NO2), it is necessary to separate the stratospheric from the tropospheric signal. The SCIAMACHY instrument offers the unique opportunity to combine its measurements in limb and nadir viewing geometries into a tropospheric data product, using the limb measurements of the stratospheric NO2 abundances to correct the nadir measurements' total columns. In this manuscript, we present a novel approach to limb/nadir matching, calculating one stratospheric NO2 value from limb measurements for every single nadir measurement, abandoning global coverage for the sake of spatial accuracy. As a comparison, modelled stratospheric NO2 columns from the Oslo CTM2 are evaluated as stratospheric correction, and both datasets are confronted with the originally used reference sector method. Our study shows that stratospheric NO2 columns from SCIAMACHY limb measurements very well reflect stratospheric conditions. The zonal variability of stratospheric NO2 is captured by our matching algorithm, and the quality of the resulting tropospheric NO2 columns improves considerably. Modelled stratospheric NO2 columns from the Oslo CTM2 agree remarkably well with the measurements. Both datasets need to be matched to the level of the nadir measurements, however, because a time and latitude dependent bias between both stratospheric datasets and the measured nadir columns can be observed over clean regions. After accounting for this systematic bias between SCIAMACHY nadir observations and the stratospheric columns, both new stratospheric correction methods provide a significant improvement to the retrieval of tropospheric NO2 columns from the SCIAMACHY instrument.

Hilboll, A.; Richter, A.; Rozanov, A.; Hodnebrog, Ø.; Heckel, A.; Solberg, S.; Stordal, F.; Burrows, J. P.

2012-07-01

13

Results on the low elevation angle propagation experiment, part 1  

Microsoft Academic Search

The impact of the lower troposphere on low elevation angle Earth-space links was studied. An X-band satellite beacon and 11 and 20 GHz radiometers conducted experiments using Intelsat V-5 at 12.5 deg elevation angle. Satellite failure led to use of Intelsat V-8 at 5 deg. Statistics on point rain rate at the receiver site, beacon attenuation, crosspolar discrimination, beacon fluctuation

Torben Pedersen

1987-01-01

14

OMPS Nadir early on-orbit performance evaluation and calibration  

NASA Astrophysics Data System (ADS)

OMPS is the latest advanced hyperspectral sensor suite flying onboard the Suomi National Polar-Orbiting Partnership (Suomi NPP) spacecraft. It measures ozone depletion in total column and vertical profile ozone abundances. OMPS on-orbit calibration is conducted through dark, lamp and solar measurements. Launched on October 28, 2011, OMPS Nadir has successfully undergone a thorough early orbit check (EOC) and is currently in the intensive calibration and validation (ICV) phase. The calibration data gathered during the on-orbit calibration and validation activities allows us to evaluate the sensor's early orbit performance and establish on-orbit calibration baseline. In this paper, we provide details of the sensor major on-orbit calibrations activities and present sensor level performance and calibration results from OMPS early orbit image data. These results have demonstrated that the OMPS has made a smooth transition from ground to orbit, and its early on-orbit performance meets or exceeds sensor level requirements and agrees with the predicted values determined during the prelaunch calibration and characterization. Examples of Nadir CCD orbital performance monitoring are provided.

Pan, C.; Weng, F.; Wu, X.; Kowalewski, M.; Jaross, G.; Flynn, L.

2012-11-01

15

Multiple emission angle surface–atmosphere separations of thermal emission spectrometer data  

Microsoft Academic Search

A method for separating the spectral signatures of the Martian surface and atmosphere was developed and is applied to multiple emission angle data returned from the MGS TES instrument. This method includes correlated-k and index gas removal algorithms that may be applied to all nadir-pointing TES data. Initial results have provided new and refined measurements of the spectral shapes of

Joshua L. Bandfield; Michael D. Smithb

2003-01-01

16

PREDICTIVE VALUE OF PROSTATE SPECIFIC ANTIGEN NADIR AFTER SALVAGE CRYOTHERAPY  

Microsoft Academic Search

PurposeWe determined nadir prostate specific antigen (PSA) after salvage cyrotherapy to distinguish patients who are potentially cured from those at risk for subsequent biochemical and biopsy proved failure.

GRAHAM F. GREENE; LOUIS L. PISTERS; SHELLIE M. SCOTT; ANDREW C. VON ESCHENBACH

1998-01-01

17

Analysis of the Astro-1/Hopkins Ultraviolet Telescope EUV-FUV dayside nadir spectral radiance measurements  

NASA Astrophysics Data System (ADS)

The Hopkins Ultraviolet Telescope (HUT) was one of three ultraviolet Astro-1 observatory instruments on space shuttle Columbia in December 1990 (STS-35), covering the 830-1850 Å wavelength interval (first order) at ˜3.3 Å spectral resolution. Satellite altitude was 360 km. Dayside nadir measurements were performed during a single orbit on 7 December 1990 under solar maximum (F10.7 = 222), geomagnetically quiet (Ap = 4) conditions, covering late morning local times (solar zenith angle < 48°). These data constitute a reference dayglow radiance spectrum comprising a number of thermospheric emission features, including several weak features neighboring bright optically thick emissions, that have not yet received adequate explanations, in part owing to questions regarding spectral intensity calibration, dynamic range, etc., associated with older data sets. In this paper, the HUT extreme ultraviolet (EUV)-far ultraviolet (FUV) nadir dayglow spectrum is presented along with the results of a modeling analysis using a development version of the Atmospheric Ultraviolet Radiance Integrated Code (AURIC). The analysis relies on currently available laboratory data and first-principles excitation and transport modeling codes and utilizes constraints drawn from the FUV spectral region data to study several EUV emissions of interest for which past airglow data are sparse. The focus is on the airglow in the 980-1200 Å region, which is particularly rich in emission features affected by thermospheric conditions. Emissions investigated in detail include (1) the optically thick OI 989 Å multiplet and associated 1172 Å fluorescence, (2) the OI 1026 Å sextuplet blended with atomic hydrogen Lyman ?, (3) the atomic nitrogen multiplets at 1134 and 1200 Å consisting of optically thick components excited by e- + N and optically thin components excited by e- + N2 and h? + N2, (4) a number of other NI and N+ features (e.g., N+ 1085 Å) excited by N2 dissociative ionization, (5) the Birge-Hopfield I (N2 BH-1) system, and (6) the resonance lines of argon (Ar 1048 and 1067 Å).

Bishop, James; Feldman, Paul D.

2003-06-01

18

Improvements in the tropical ozone profile retrieval from GOME-UV/Vis nadir spectra  

NASA Astrophysics Data System (ADS)

The Global Ozone Monitoring Experiment (GOME) is a nadir viewing grating spectrometer measuring radiances in the visible and ultraviolet spectral range. The analysis of sun-normalized nadir spectra from GOME enables us to retrieve height resolved ozone distributions. The retrieval is based upon the FURM algorithm (Full Retrieval Method) which uses the advanced optimal estimation scheme. The spectral data require accurate radiometric calibration with regard to the increasing degradation of the instrument with time. In this paper, a calibration and degradation correction will be presented which enables us to extend the spectral range to shorter wavelengths enhancing the stratospheric information content of the retrieved profiles. This helps to avoid non-physical profile structures often observed in the tropics, where the ozone maximum is sensitive to this spectral range. Results in the low latitude range are compared with experimental results from the HALogen Occultation Experiment (HALOE) and retrieval results from former versions of FURM and show generally much better agreement.

Tellmann, S.; Rozanov, V. V.; Weber, M.; Burrows, J. P.

2004-01-01

19

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

20

Comparison of OClO nadir measurements from SCIAMACHY and GOME  

NASA Astrophysics Data System (ADS)

The scanning imaging absorption spectrometer for atmospheric chartography was launched successfully onboard ENVISAT on March 1, 2002. It observes the solar radiation transmitted and backscattered from the atmosphere and reflected from the ground in nadir, limb and occultation viewing modes. Chlorine dioxide (OClO), an important indicator for stratospheric chlorine activation, can be measured in the UV spectral range by differential optical absorption spectroscopy (DOAS). First results of the DOAS retrieval of OClO slant column densities from the SCIAMACHY nadir measurements are presented and compared to measurements of the global ozone monitoring experiment (GOME), which has successfully measured OClO since 1995. While SCIAMACHY operates in the same orbit, it measures ?30 min earlier than GOME and has an increased spatial resolution (30 × 60 km2 compared to 40 × 320 km2 for GOME).

Kühl, Sven; Wilms-Grabe, Walburga; Frankenberg, Christian; Grzegorski, Michael; Platt, Ulrich; Wagner, Thomas

21

Nadir CA-125 level as prognosis indicator of high-grade serous ovarian cancer  

PubMed Central

Purpose The capacity of nadir CA-125 levels to predict the prognosis of epithelial ovarian cancer remains controversial. This study aimed to explore whether the nadir CA-125 serum levels could predict the durations of overall survival (OS) and progression free survival (PFS) in patients with high-grade serous ovarian cancer (HG-SOC) from the USA and PRC. Materials and methods A total of 616 HG-SOC patients from the MD Anderson Cancer Center (MDACC, USA) between 1990 and 2011 were retrospectively analyzed. The results of 262 cases from the Jiangsu Institute of Cancer Research (JICR, PRC) between 1992 and 2011 were used to validate the MDACC data. The CA-125 immunohistochemistry assay was performed on 280 tissue specimens. The Cox proportional hazards model and the log-rank test were used to assess the associations between the clinicopathological characteristics and duration of survival. Results The nadir CA-125 level was an independent predictor of OS and PFS (p?nadir CA-125 levels (?10 U/mL) were associated with longer OS and PFS (median: 61.2 and 16.8 months with 95% CI: 52.0–72.4 and 14.0–19.6 months, respectively) than their counterparts with shorter OS and PFS (median: 49.2 and 10.5 months with 95% CI: 41.7–56.7 and 6.9–14.1 months, respectively). The nadir CA-125 levels in JICR patients were similarly independent when predicting the OS and PFS (p?Nadir CA-125 levels less than or equal to 10 U/mL were associated with longer OS and PFS (median: 59.9 and 15.5 months with 95% CI: 49.7–70.1 and 10.6–20.4 months, respectively), as compared with those more than 10 U/mL (median: 42.0 and 9.0 months with 95% CI: 34.4–49.7 and 6.6–11.2 months, respectively). Baseline serum CA-125 levels, but not the CA-125 expression in tissues, were associated with the OS and PFS of HG-SOC patients in the MDACC and JICR groups. However, these values were not independent. Nadir CA-125 levels were not associated with the tumor burden based on second-look surgery (p?=?0.09). Patients who achieved a pathologic complete response had longer OS and PFS (median: 73.7 and 20.7 months with 95% CI: 63.7–83.7 and 9.5–31.9 months, respectively) than those with residual tumors (median: 34.6 and 10.6 months with 95% CI: 6.9–62.3 and 4.9–16.3 months, respectively). Conclusions The nadir CA-125 level was an independent predictor of OS and PFS in HG-SOC patients. Further prospective studies are required to clinically optimize the chances for a complete clinical response of HG-SOC cases with higher CA-125 levels (>10 U/mL) at the end of primary treatment.

2013-01-01

22

On the vehicle sideslip angle estimation through neural networks: Numerical and experimental results  

NASA Astrophysics Data System (ADS)

Stability control systems applying differential braking to inner/outer tires are nowadays a standard for passenger car vehicles (ESP, DYC). These systems assume as controlled variables both the yaw rate (usually measured on board) and the sideslip angle. Unfortunately this latter quantity can directly be measured only through very expensive devices however unsuitable for ordinary vehicle implementation and thus it must be estimated. Several state observers eventually adapting the parameters of their reference vehicle models have been developed at the purpose. However sideslip angle estimation is still an open issue. In order to avoid problems concerned with reference model parameters identification/adaptation, a layered neural network approach is proposed in this paper to estimate the sideslip angle. Lateral acceleration, yaw rate, speed and steer angle which can be acquired by ordinary sensors are used as inputs. The design of the neural network and the definition of the manoeuvres constituting the training set have been gained by means of numerical simulations with a 7 d.o.f.s vehicle model. Performance and robustness of the implemented neural network have subsequently been verified by post-processing the experimental data acquired with an instrumented vehicle and referred to several handling manoeuvres (step-steer, power on, double lane change, etc.) performed on various road surfaces. Results generally show a good agreement between the estimated and the measured sideslip angle.

Melzi, S.; Sabbioni, E.

2011-08-01

23

Results of Monocular Surgery Under Peribulbar Anesthesia for Large-Angle Horizontal Strabismus  

PubMed Central

OBJECTIVE: To evaluate the results of monocular surgery under peribulbar anesthesia for large-angle horizontal strabismus. INTRODUCTION: Monocular surgery may preserve some muscles if a repeat operation is required, may help to avoid the exposure of the dominant eye to the inherent risks of a surgical procedure and may reduce surgical time. METHODS: We evaluated ninety-two consecutive patients who underwent monocular surgery under peribulbar anesthesia for large-angle horizontal strabismus (angle of 40 prism diopters or greater). Patients were divided into group 1- esotropia and group 2 –exotropia. The postoperative follow-up was at 6 months, when the residual deviation was evaluated. In cases of residual deviations of over 15 PD (prism diopter), a second procedure was indicated. RESULTS: In all patients with preoperative deviations up to 60 PD, residual deviations were under 15 PD. Some patients with preoperative deviations of 65 PD (two in group 1 and four in group 2) and all patients with deviations over 65 PD had residual deviations over 15 PD. The 13 patients who underwent a second procedure experienced successful outcomes. Our ROC curve analysis showed that the cutoff point for obtaining a successful surgical result was 62.5 PD. No patient presented with a major limitation in respect of ocular movement. CONCLUSIONS: Monocular surgery under peribulbar anesthesia can be an alternative for horizontal large-angle strabismus given deviations of up to 60 PD. Monocular surgery did not result in successful outcomes for deviations of over 65 PD.

Millan, Tatiana; de Carvalho, Keila Monteiro; Minguini, Nilza

2009-01-01

24

Uncontrolled primary angle closure glaucoma: results of early intercapsular cataract extraction and posterior chamber lens implantation  

Microsoft Academic Search

In this study we retrospectively evaluated the effect of intercapsular or extracapsular cataract extraction and posterior chamber lens implantation in 67 eyes of 57 patients with different types of primary angle closure glaucoma (PACG) in combination with cataract. We subdivided this patient population into three groups, based on the preoperative methods of intraocular pressure (IOP) control. The best results were

F. P. Gunning; E. L. Greve

1991-01-01

25

The PSA nadir that indicates potential cure after radiotherapy for prostate cancer  

Microsoft Academic Search

ObjectivesThe prostate-specific antigen nadir that indicates potential cure by radiotherapy has never been established. We determined this nadir level and used it to define precisely disease freedom after radiotherapy.

Frank A. Critz; A. Keith Levinson; W. Hamilton Williams; David A. Holladay; Clinton T. Holladay; Eric A. Klein; Patrick J. Kupelian

1997-01-01

26

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

Microsoft Academic Search

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

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

1999-01-01

27

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

Microsoft Academic Search

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

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

2000-01-01

28

Retrieval of tropospheric column densities of NO2 from combined SCIAMACHY nadir/limb measurements  

NASA Astrophysics Data System (ADS)

The SCIAMACHY instrument onboard the ESA satellite ENVISAT allows the retrieval of column densities of various trace gases, among them NO2. As only instrument of its kind, SCIAMACHY measures in an alternating limb/nadir mode. The limb measurements allow a direct determination of stratospheric column densities, which are needed to extract tropospheric from the total column density measurements performed in (quasi simultaneous) nadir geometry. Here we discuss the potential and limitations of SCIAMACHY limb measurements for estimating stratospheric column densities of NO2 in comparison to a simple reference sector method, and the consequences for the resulting tropospheric column densities. A direct, absolute limb correction scheme improves spatial patterns of tropospheric NO2 column densities at high latitudes compared to the simple reference sector method. However, it results in artificial zonal stripes at low latitudes. Thus, also a relative limb correction scheme was defined, which turned out to successfully reduce stratospheric artefacts in the resulting tropospheric data product without introducing new ones. This relative limb correction scheme is rather simple, robust, and, in essence, based on measurements alone. The effect of the different stratospheric estimation schemes on tropospheric column densities is discussed with respect to zonal and temporal dependencies. In addition, error quantities are defined from the nadir/limb measurements which indicate remaining systematic errors as function of latitude and day. Our new suggested stratospheric estimation scheme, the relative limb correction, improves monthly mean tropospheric slant column densities significantly, e.g. from -1×1015 molec/cm2 (using a simple reference sector method) to ?0 in the Atlantic ocean, and from +1×1015 molec/cm2 to ?0 over Siberia, at 50° N in January.

Beirle, S.; Kühl, S.; Puä·Ä«Te, J.; Wagner, T.

2009-11-01

29

Retrieval of tropospheric column densities of NO2 from combined SCIAMACHY nadir/limb measurements  

NASA Astrophysics Data System (ADS)

The SCIAMACHY instrument onboard the ESA satellite ENVISAT allows measurements of various atmospheric trace gases, such as NO2. A unique feature of SCIAMACHY is that measurements are made alternately in limb and nadir mode. The limb measurements provide an opportunity for directly determining stratospheric column densities (CDs), which are needed to extract tropospheric CDs from the total CD measurements performed in (quasi simultaneous) nadir geometry. Here we discuss the potential and limitations of SCIAMACHY limb measurements for estimating stratospheric CDs of NO2 in comparison to a simple reference sector method, and the consequences for the resulting tropospheric CDs. A direct, absolute limb correction scheme is presented that improves spatial patterns of tropospheric NO2 column densities at high latitudes, but results in artificial zonal stripes at low latitudes. Subsequently, a relative limb correction scheme is introduced that successfully reduces stratospheric artefacts in the tropospheric data product without introducing new ones. This relative limb correction scheme is rather simple, robust, and, in essence, based on measurements alone. The effects of the different stratospheric estimation schemes on tropospheric CDs are discussed with respect to zonal and temporal dependencies. In addition, we define error quantities from the nadir/limb measurements that indicate remaining systematic errors as a function of latitude and day. Our new suggested stratospheric estimation scheme, the relative limb correction, improves mean tropospheric slant CDs significantly, e.g. from -1×1015 molec/cm2 (using a reference sector method) to ?0 in the Atlantic ocean, and from +1×1015 molec/cm2 to ?0 over Siberia, at 50° N in January 2003-2008.

Beirle, S.; Kühl, S.; Puä·Ä«Te, J.; Wagner, T.

2010-02-01

30

Tropospheric column amount of ozone retrieved from SCIAMACHY limb-nadir-matching observations  

NASA Astrophysics Data System (ADS)

Tropospheric ozone, O3, has two sources: transport from the stratosphere and photochemical production in the troposphere. It plays important roles in atmospheric chemistry and climate change. In this manuscript we describe the retrieval of tropospheric O3 columns from limb-nadir matching (LNM) observations of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument, which flies as part of the payload onboard the European Space Agency (ESA) satellite Envisat. This retrieval technique is a residual approach that utilizes the subtraction of the stratospheric O3 columns, derived from the limb observations, from the total O3 columns, derived from the nadir observations. The technique requires accurate knowledge of the stratospheric O3 columns, the total O3 columns, tropopause height, and their associated errors. The stratospheric O3 columns were determined from the stratospheric O3 profile retrieved in the Hartley and Chappius bands, based on SCIAMACHY limb scattering measurements. The total O3 columns were also derived from SCIAMACHY measurements, in the nadir viewing mode using the Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) technique in the Huggins band. Comparisons of the tropospheric O3 columns from SCIAMACHY and collocated measurements from ozonesondes, in both hemispheres between January 2003 and December 2011 show agreement to within 2-5 DU (1 DU = 2.69 × 1016 molecules cm-2). Comparison of tropospheric O3 from SCIAMACHY with the results from ozonesondes, the Tropospheric Emission Spectrometer (TES), and the LNM method combining Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) data (hereinafter referred to as OMI/MLS), have been investigated. We find that all four retrieved data sets show agreement within the error bars and exhibit strong seasonal variation, which differs in amplitude. The spatial distribution of tropospheric ozone observed shows pollution plumes related to the release of precursors at the different seasons in both hemispheres.

Ebojie, F.; von Savigny, C.; Ladstätter-Weißenmayer, A.; Rozanov, A.; Weber, M.; Eichmann, K.; Bötel, S.; Rahpoe, N.; Bovensmann, H.; Burrows, J. P.

2013-08-01

31

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

NASA Astrophysics Data System (ADS)

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 processing methods and presents the first results from this experiment. A precision of 2 cm has been achieved on the difference of vertical coordinates from two sets of sim 3000 distance measurements. Results are consistent with simulations and a posteriori covariance. A drastic data sorting for outliers, due to strong overlap of reflected echoes, has been necessary. Hence, the actual number of measurements and the positioning precision became relatively small. Higher precision is expected in future experiments, once the instrument's link budget will be improved.

Bock, O.

2000-04-01

32

Off-nadir optical remote sensing from satellites for vegetation identification  

SciTech Connect

Today's satellite remote sensing systems rely heavily on spectral signatures for scene identification from nadir observations. We propose to use angular signatures as complementary scene identifiers when off-nadir sensing is possible. Specifically, the hot spot (Heiligenschein) of plant canopies is recognized as an atmosphere-invariant angular reflectance signature that carries information about the plant stand architecture which may be useful for instant crop identification from off-nadir satellite measurements.

Gerstl, S.A.W.

1986-05-30

33

Angles, Angles and More Angles!  

NSDL National Science Digital Library

Test Your Angle Knowledge! Angles Telescope Star Gazing Help diget to fill up his scrapbook of stars by using his telescope and pointting at each planet during the night! But make sure you hurry before the sun comes up! Shoot The Space Ship Angles Game Try and figure out which angle you need to use to shoot down the aliens spaceship! ...

Smith, Miss

2011-03-23

34

Improvements to the retrieval of tropospheric NO2 from satellite - stratospheric correction using SCIAMACHY limb/nadir matching and comparison to Oslo CTM2 simulations  

NASA Astrophysics Data System (ADS)

Satellite measurements of atmospheric trace gases have proved to be an invaluable tool for monitoring the Earth system. When these measurements are to be used for assessing tropospheric emissions and pollution, as for example in the case of nadir measurements of nitrogen dioxide (NO2), it is necessary to separate the stratospheric from the tropospheric signal. The SCIAMACHY instrument offers the unique opportunity to combine its measurements in limb- and nadir-viewing geometries into a tropospheric data product, using the limb measurements of the stratospheric NO2 abundances to correct the nadir measurements' total columns. In this manuscript, we present a novel approach to limb/nadir matching, calculating one stratospheric NO2 value from limb measurements for every single nadir measurement, abandoning global coverage for the sake of spatial accuracy. For comparison, modelled stratospheric NO2 columns from the Oslo CTM2 are also evaluated for stratospheric correction. Our study shows that stratospheric NO2 columns from SCIAMACHY limb measurements very well reflect stratospheric conditions. The zonal variability of the stratospheric NO2 field is captured by our matching algorithm, and the quality of the resulting tropospheric NO2 columns improves considerably. Both stratospheric datasets need to be adjusted to the level of the nadir measurements, because a time- and latitude-dependent bias to the measured nadir columns can be observed over clean regions. After this offset is removed, the two datasets agree remarkably well, and both stratospheric correction methods provide a significant improvement to the retrieval of tropospheric NO2 columns from the SCIAMACHY instrument.

Hilboll, A.; Richter, A.; Rozanov, A.; Hodnebrog, Ø.; Heckel, A.; Solberg, S.; Stordal, F.; Burrows, J. P.

2013-03-01

35

PITCH-ANGLE SCATTERING: RESONANCE VERSUS NONRESONANCE, A BASIC TEST OF THE QUASILINEAR DIFFUSIVE RESULT  

SciTech Connect

Due to the very broad range of the scales available for the development of turbulence in space and astrophysical plasmas, the energy at the resonant scales of wave-particle interaction often constitutes only a tiny fraction of the total magnetic turbulent energy. Despite the high efficiency of resonant wave-particle interaction, one may therefore question whether resonant interaction really is the determining interaction process between particles and turbulent fields. By evaluating and comparing resonant and nonresonant effects in the frame of a quasilinear calculation, the dominance of resonance is here put to the test. By doing so, a basic test of the classical resonant quasilinear diffusive result for the pitch-angle scattering of charged energetic particles is also performed.

Ragot, B. R. [Helio Research, P.O. Box 1414, Nashua, NH 03061 (United States)

2012-01-01

36

Lateral and axial resolutions of an angle-deviation microscope for different numerical apertures: experimental results  

NASA Astrophysics Data System (ADS)

This paper presents a study of the lateral and axial resolutions of a transmission laser-scanning angle-deviation microscope (TADM) with different numerical aperture (NA) values. The TADM is based on geometric optics and surface plasmon resonance principles. The surface height is proportional to the phase difference between two marginal rays of the test beam, which is passed through the test medium. We used common-path heterodyne interferometry to measure the phase difference in real time, and used a personal computer to calculate and plot the surface profile. The experimental results showed that the best lateral and axial resolutions for NA = 0.41 were 0.5 ?m and 3 nm, respectively, and the lateral resolution breaks through the diffraction limits.

Chiu, Ming-Hung; Lai, Chin-Fa; Tan, Chen-Tai; Lin, Yi-Zhi

2011-03-01

37

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

NASA Astrophysics Data System (ADS)

Based on atomistic molecular dynamics (MD) simulations, the small angle neutron scattering (SANS) intensity behavior of a single generation-4 polyelectrolyte polyamidoamine 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. The consistency found in comparison against previously published experimental findings (W.-R. Chen, L. Porcar, Y. Liu, P. D. Butler, and L. J. Magid, Macromolecules 40, 5887 (2007)) leads to a link between the neutron scattering experiment and MD computation, and fresh perspectives. The simulations enable scattering calculations of not only the hydrocarbons but also the contribution from the scattering length density fluctuations caused by structured, confined water within the dendrimer. Based on our computational results, we explore the validity of using radius of gyration RG for microstructure characterization of a polyelectrolyte dendrimer from the scattering perspective.

Wu, Bin; Kerkeni, Boutheïna; Egami, Takeshi; Do, Changwoo; Liu, Yun; Wang, Yongmei; Porcar, Lionel; Hong, Kunlun; Smith, Sean C.; Liu, Emily L.; Smith, Gregory S.; Chen, Wei-Ren

2012-04-01

38

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

39

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

NASA Astrophysics Data System (ADS)

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

Wu, Aisheng; Xiong, Xiaoxiong

2012-09-01

40

Capabilities of multi-angle polarization cloud measurements from satelite: Polder results  

NASA Astrophysics Data System (ADS)

As a component of the new generation of earth-orbiting instruments designed for Earth's observation, the POLDER (Polarization and Directionality of the Earth's Reflectances) radiometer consist of a wide field-of-view device, a multi-angle viewing capability, spectral filters and polarizers . When the satellite passes over a target, a tenth of different images are acquired in several narrow spectral bands of the visible and near-infrared spectrum. This new type of multi-angle instruments offer new opportunity for deriving cloud parameters at global scale. The aim of this presentation will be to point out the main contributions of such an instrument for cloud study through its original instrumental capabilities (multidirectionality, polarization, and spectral measurements when used). These capabilities will be mainly illustrated by using POLDER-1 derived cloud parameters which are operationally processed by CNES (the French Space Agency) and available since the beginning of 1999. The multi-directional capability of POLDER allows for checking schemes of cloud optical thickness retrieval. That cloud parameter can be derived from bidirectional reflectance measurements. However, this needs some assumptions both on cloud microphysics and on cloud morphology and spatial distribution. While it is always possible to find a cloud model that satisfies one single bidirectional observation of a given cloud target, it is not so easy to fulfill the complete set of ten or more observations provided by multidirectional instruments. Consequently, it will be shown that POLDER not only allows for determining cloud optical thickness under some hypotheses, but it also enable us to test the validity of these hypotheses. Without a doubt, the most original characteristics of POLDER is its ability to measure the polarized component of the Earth-atmosphere reflected light. However, as illustrated in the presentation, it clearly appears that multi-angle capability is necessary for taking advantage of polarization. For instance, polarization and multi- directionality allow for determining the cloud phase, which is one of the more important cloud parameter for climate models. Finally, we will illustrate a recent tentative for deriving top-of-the-atmosphere Earth radiation budget from POLDER. These results will be compared to the ERBE, ScaRaB and CERES records. It will be shown that global maps of POLDER albedo reveal strong deviations in the Tropical Pacific, that correspond to the beginning of the 1997-1998 ENSO event

Parol, F.; Buriez, J.; Vanbauce, C.; Riedi, J.; Labonnote, L. C.; Boucher, M.; Vesperini, M.; Seze, G.; Couvert, P.; Viollier, M.

41

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

SciTech Connect

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 ({approx}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 (r{sup 2}>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.

Boone, John M. [Department of Radiology and Department of Biomedical Engineering, UC Davis Medical Center, University of California, Davis, 4860 Y Street, Suite 3100, Sacramento, California 95817 (United States)

2010-01-15

42

Inner Jet Spread Angles of Coaxial Jets from Subcritical to Supercritical Conditions with Preliminary Numerical Results.  

National Technical Information Service (NTIS)

A study is performed to analyze the behavior of the inner jet spread angles in a coaxial jet flow configuration similar to those used in liquid rocket engines. These angles are measured from back-lit images. Data is presented for sub-, near-, and supercri...

D. Talley H. Lyu I. A. Leyva J. I. Rodriguez J. J. Graham

2008-01-01

43

Prostate specific antigen nadir following external beam radiation therapy for clinically localized prostate Cancer: The relationship between nadir level and disease-free survival  

Microsoft Academic Search

PurposeWe determined whether the prostate specific antigen (PSA) nadir achieved following external beam radiation therapy alone predicts biochemical disease-free survival in a large cohort of men with clinically localized prostate cancer.

W. Robert Lee; Alexandria L. Hanlon; Gerald E. Hanks

1996-01-01

44

Acute Angle-Closure Glaucoma Resulting From Spontaneous Hemorrhagic Retinal Detachment in Age-related Macular Degeneration  

Microsoft Academic Search

Purpose: Acute angle-closure glaucoma resulting from massive subretinal hemorrhage is a rare and catastrophic complication in age-related macular degeneration. Anticoagulant usage had been strongly correlated with this complication in previously reported cases.Methods: Four patients (4 eyes), 3 men and 1 woman, developed angle-closure glaucoma with diffuse subretinal hemorrhage and total hemorrhagic retinal detachment.Results: Serial funduscopic examinations and echographic studies in

San-Ni Chen; Cheng-Lien Ho; Jau-Der Ho; Ya-Hui Guo; Tun-Lu Chen; Ping-Fan Chen

2001-01-01

45

[Results of 1-year use of local pindolol in open-angle glaucoma].  

PubMed

In a randomized and controlled study (already published) the efficacy and safety of Pindolol eye drops 1% were compared with Timolol eye drops 0.5% in the treatment of open-angle glaucoma over a period of 6 months. With the exception of some allergic reactions there was no difference between the two with regard to IOP and the other parameters documented, such as pulse, blood pressure, visual acuity, refraction, diameter of pupils, tear production, visual field and biomicroscopic and ophthalmoscopic. In this article, the authors report on the results of prolongation of treatment in the 33 patients of the Pindolol group from month 7 to month 12 in an open-case study. The effect on IOP after 12 months was no different from that after month 6. There was no difference with regard to pulse and blood pressure, either. Four patients had to discontinue the treatment, in one case owing to drug-related side effects on the lids and conjunctiva. The other parameters documented (visual acuity, visual field, refraction, diameter of pupils, tear production, corneal sensitivity and biomicroscopic and ophthalmoscopic examination) revealed no difference between the first and the second 6 months. A diminution of the effect of the drug on the level and duration of IOP was ruled out. PMID:3974160

Stryz, J R; Merté, H J

1985-01-01

46

Wide-angle high-resolution line-imager prototype flight test results  

NASA Astrophysics Data System (ADS)

A single-channel prototype pushbroom imager has been developed to the specifications required for forestry remote-sensing applications and for mapping. It is based on a commercially available 6000-element linear array for which a special wide-angle, high modulation transfer function lens was designed and fabricated. The test was flown aboard a twin-engine jet aircraft. The sensor has produced high-quality imagery with pixel sizes down to 25 cm.

Neville, R. A.; Marois, R.; Schwarz, J. W.; Till, S. M.

1992-06-01

47

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

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

Long-term stability of Angle Class II, Division 1 malocclusions with successful occlusal results at end of active treatment  

Microsoft Academic Search

The purpose of this study was to examine long-term stability of Angle Class II, Division 1 malocclusions with successful occlusal results at the end of active appliance therapy, search for predictors of relapse, and look for characteristics associated with successful treatment. Records taken before and after treatment and a mean of 14.0 years postretention of adolescent patients treated for a

Brett C. Fidler; Jon Årtun; Donald R. Joondeph; Robert M. Little

1995-01-01

50

Different experimental results for the influence of immersion angle on the resonant frequency of a quartz crystal microbalance in a liquid phase: With a comment  

Microsoft Academic Search

This paper presents different experimental results of the influence of an immersion angle (?, the angle between the surface of a quartz crystal resonator and the horizon) on the resonant frequency of a quartz crystal microbalance (QCM) sensor exposed one side of its sensing surfaces to liquid. The experimental results show that the immersion angle is an added factor that

Dazhong Shen; Qi Kang; Xiaoyu Li; Hongmei Cai; Yuandong Wang

2007-01-01

51

Spatial and Temporal distribution of CO_{2} 4.3-mu m NLTE Emission from nadir VIRTIS-H/Venus Express observations  

NASA Astrophysics Data System (ADS)

Non-Local Thermodynamic Equilibrium (non-LTE) emissions are known to play a key role in the radiative heating and cooling of the Venus mesosphere and lower thermosphere (Dickinson, JAS, 1973; Roldan et al., Icarus, 2000). In the case of the Venusian atmosphere, CO2 vibrational-rotational emissions at 4.3 ?m and 2.7 ?m were predicted to give intense emissions, and since they are originated between 80 and 150 km, their observation might give information on the atmospheric parameters at those altitudes, depending on sensitivity and spectral resolution. The VIRTIS spectrometer on board Venus Express allows for the first time the systematic sounding of these bands in the Venus atmosphere, both in nadir and limb observing geometries. The limb data by VIRTIS has been recently studied by our team (Gilli et al., JGR, 2009; López-Valverde et al., 2010 submitted; Gilli et al., 2010 submitted), focusing on its vertical distribution and the validation of non-LTE models, but an exhaustive study of nadir observations has not been presented so far, except for the detection of gravity waves by García et al. (2008; 2009). In this work, we have used the nadir observations to study the horizontal distribution of the CO2 non-LTE emissions at 4.3 ?m, mainly originated at altitudes about ~110 km. The analyzed dataset comprises the whole nadir measurements with VIRTIS-H (the highest spectral resolution channel) obtained up to September 2009, covering nearly 900 days of observations and more than 140,000 spectra. Similarly to the case of limb data, it was found that the nadir radiance depends not only on the Solar Zenith Angle, but also on the Emission Angle, as predicted by our non-LTE model. After careful radiance averages, the small dispersion found in the mean emission of this band suggests that the Venus lower thermosphere is more stable than expected, with scarce episodes of significant variation during the studied period. Since the spectral resolution of VIRTIS-H allows separating different CO2 isotopic and hot bands, this dataset implies a valuable test for non-LTE models. Therefore, a revision of some key rate coefficients for collisional relaxation of CO2 vibrational energy levels is also carried out, by means of a systematic comparison between radiance ratios measured by VIRTIS-H and the ones obtained with our non-LTE radiative transfer model. Conclusions will be briefly discussed at the meeting.

Peralta, Javier; Ángel López-Valverde, Miguel; Gilli, Gabriella; Drossart, Pierre; Piccioni, Giuseppe

2010-05-01

52

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

53

Boom Deployment Angle Estimation and On-orbit Operation Results of ETS-VIII Large Deployable Reflectors  

NASA Astrophysics Data System (ADS)

Engineering Test Satellite-VIII (ETS-VIII) is equipped with two large deployable reflectors (receiver (RX) and transmitter (TX) LDRs) that are deployed on orbit. The deployment sequence consists of two steps: one is the boom deployment step and the other is the reflector deployment step. The results of deployment at each step is monitored by a camera attached to the satellite. In order to deal with off-nominal scenarios due to camera malfunctions, the boom deployment angle is estimated from the telemetry data obtained from the attitude and orbit control system (AOCS) as well as the images captured by the camera. This paper deals with the estimation of the boom deployment angle from the AOCS telemetry data; further, the results of the on-orbit deployment are presented.

Shima, Takeya; Tanaka, Hidekazu; Yonechi, Hiroo; Yamada, Katsuhiko; Meguro, Akira; Usui, Motofumi; Shintate, Kyoji

54

A statistical study of UHF auroral backscatter at large magnetic aspect angle: A reanalysis of unpublished results from 1968  

Microsoft Academic Search

In 1968 a joint study of radar-auroral backscatter was carried out by Bell Laboratories, Western Electric, and Lincoln Laboratory using the 448-MHz radar of the Prince Albert Radar Laboratory. They made observations covering a range of magnetic aspect angles from 4.5° to 16°, but the results were not published in the open literature. These data have been reanalyzed and used

D. R. Moorcroft

1996-01-01

55

A statistical study of UHF auroral backscatter at large magnetic aspect angle: A reanalysis of unpublished results from 1968  

Microsoft Academic Search

In 1968 a joint study of radar-auroral backscatter was carried out by Bell Laboratories, Western Electric, and Lincoln Laboratory using the 448-MHz radar of the Prince Albert Radar Laboratory. They made observations covering a range of magnetic aspect angles from 4.5 ø to 16 ø, but the results were not published in the open literature. These data have been reanalyzed

D. R. Moorcroft

1996-01-01

56

Retrieval of tropospheric ozone columns from SCIAMACHY limb-nadir matching observations  

NASA Astrophysics Data System (ADS)

Satellite observations of tropospheric ozone are of critical importance in obtaining a global and more thorough knowledge of the phenomena affecting air quality. Tropospheric ozone has a significant adverse effect on the climate system. In the lower troposphere, during summer, it is a major constituent of photochemical smog and excess of it is toxic to the ecosystem, animal and man. It is equally known as a major oxidant and also involved in the production of other oxidants such as hydroxyl (OH) radicals. In the middle and upper troposphere, ozone acts as a greenhouse gas. The retrieval of tropospheric ozone from UV/VIS/NIR satellite spectrometer such as the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the ESA satellite Envisat is difficult because only about 10 % of the Total Ozone Column (TOC) is in the troposphere. In this analysis we present the retrieval of tropospheric ozone columns from SCIAMACHY limb-nadir matching observations. This technique is a residual approach that involves the subtraction of the stratospheric ozone columns derived from the limb observations from the total ozone columns derived from the nadir observations. The stratospheric ozone columns were derived by integrating the stratospheric ozone profiles from the tropopause, which was obtained from the re-analyses data of the European Centre for Medium-Range Weather Forecasts (ECMWF) in 1.5o x 1.5o x 91 levels based on both the thermal definition of tropopause using the WMO lapse-rate criterion as well as the potential vorticity definition of the tropopause. The total ozone columns were on the other hand retrieved using the Weighting Function DOAS algorithm (WFDOAS) at the spectral window of 326.6 - 334.5 nm. Equally of importance in our analysis is the tropospheric ozone columns derived from the ozonesondes by integrating the tropospheric ozone profiles from the bottom to the top of the troposphere, which was determined from the ozonesondes temperature profile measurements using the WMO lapse rate criterion definition of the thermal tropopause. Our retrievals are compared with retrievals from ozonesondes and other satellites instruments, with results showing good comparability with some slight deviations of about 5 - 10 DU. Finally, some possible sources of error in our analysis are discussed.

Ebojie, F.; Savigny, C.; Ladstätter-Weissenmayer, A.; Bötel, S.; Weber, M.; Alexei, R.; Bovensmann, H.; Burrows, J.

2012-04-01

57

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

58

ULTRASENSITIVE SERUM PROSTATE SPECIFIC ANTIGEN NADIR ACCURATELY PREDICTS THE RISK OF EARLY RELAPSE AFTER RADICAL PROSTATECTOMY  

Microsoft Academic Search

Purpose:Ultrasensitive prostate specific antigen (PSA) assays allow a lower limit of detection (less than 0.01 ng\\/ml) than standard PSA assays. In this study we examined the ability of ultrasensitive PSA nadir to predict relapse after radical prostatectomy (RP).

SAMSON SHEN; HERBERT LEPOR; ROBERT YAFFEE; SAMIR S. TANEJA

2005-01-01

59

Improved total ozone retrieval from nadir UV GOME and SCIAMACHY data  

Microsoft Academic Search

An improved ozone column retrieval algorithm is presented which is applicable to nadir UV spectral data from GOME (1995-present) and SCIAMACHY (2002-present). Instead of fitting slant columns which have to be translated into vertical columns using airmass factors as in the standard Differential Optical Absorption Spectroscopy DOAS, we fit directly the vertical columns using weighting functions instead of absorption cross

M. Coldewey-Egbers; M. Weber; M. Buchwitz; J. P. Burrows

2003-01-01

60

OSRMS (Ocean Surface Roughness Measurement System): The DREP (Defence Research Establishment Pacific) Near-Nadir Scatterometer.  

National Technical Information Service (NTIS)

The ocean surface roughness measurement system (OSRMS) is a near-nadir-directed infrared (IR) scatterometer. It has been used to measure ocean-surface parameters and particularly for the examination from an aircraft of internal waves. This paper gives a d...

B. A. Hughes L. C. Pempel S. J. Hughes

1988-01-01

61

Posttreatment prostate-specific antigen nadir highly predictive of distant failure and death from prostate cancer  

Microsoft Academic Search

Purpose: To link posttreatment biochemical profiles to distant failure and cause-specific survival by assessing the relationship between posttreatment prostate-specific antigen (PSA) nadir and PSA doubling time (PSADT) with these outcome measures.Methods and Materials: A total of 615 men were treated at the Fox Chase Cancer Center between April 1989 and December 1995 with three-dimensional conformal radiotherapy alone (median dose 73

Alexandra L Hanlon; Hasmik Diratzouian; Gerald E Hanks

2002-01-01

62

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

PubMed

Freeze/thaw-induced embolism was studied in leaves of field-grown snow gum (Eucalyptus pauciflora) subject to frequent morning frosts. Juvenile trees were grown in buried pots, brought to the laboratory at different stages of acclimation and subjected to simulated frost-freezes (at 2 degrees C h(-1)) to nadir temperatures of -3 or -6 degrees C, which snow gums commonly experience. Frost-frozen and subsequently thawed leaves were cryo-fixed to preserve the distribution of water and were then examined by cryo-scanning electron microscopy. No embolisms were found in leaves frozen to -3 degrees C and thawed. In contrast, 34% of vessels were embolized in thawed leaves that had been frozen to -6 degrees C. This difference was seen also in the extent of extracellular ice blocks in the mid-vein expansion zones in leaves frozen to -3 and -6 degrees C, which occupied 3 and 14% of the mid-vein area, respectively. While the proportion of embolism depended on nadir temperature, it was independent of season (and hence of acclimation state). From the observation that increased embolism at lower nadir temperature was related to the freeze-induced redistribution of water, we hypothesize that the dehydration of cell walls and cells caused by the redistribution exerts sufficient tension on xylem water to induce cavitation on thawing. PMID:17087458

Ball, M C; Canny, M J; Huang, C X; Egerton, J J G; Wolfe, J

2006-05-01

63

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.

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

2013-01-01

64

Baseline BMI is a Strong Predictor of Nadir BMI after Adolescent Gastric Bypass  

PubMed Central

Objective Surgical treatment of extreme obesity may be appropriate for some adolescents. We hypothesized that surgical weight loss outcomes may differ by preoperative level of extreme obesity (body mass index [BMI] ?99th percentile). Study design A longitudinal assessment of clinical characteristics from 61 adolescents who underwent laparoscopic Roux-en-Y gastric bypass at a single pediatric center from 2002 until 2007 was performed. Patients were categorized into 1 of 3 preoperative BMI groups: group 1, BMI = 40.0 to 54.9 (n = 23); group 2, BMI = 55.0 to 64.9 (n = 21); group 3, BMI = 65.0 to 95.0 (n = 17). Changes in BMI and cardiovascular risk factors between baseline and year 1 were evaluated using repeated-measures mixed linear modeling. Results BMI in the overall cohort at baseline (60.2 ± 11 kg/m2) decreased by 37.4% at 1 year after surgery (P < .001). Percent BMI change varied little by preoperative BMI groups (?37.2%, ?36.8%, and ?37.7% for groups 1, 2, and 3 respectively; P = .8762). The rate of change in absolute BMI units significantly varied by preoperative BMI class (group × time interaction, P < .0001), with 1-year nadir BMI values for groups 1, 2, and 3 falling to 31 ± 4 kg/m2, 38 ± 5 kg/m2, and 47 ± 9 kg/m2, respectively. One year after surgery, only 17% of patients achieved a nonobese BMI (<30 kg/m2). Significant improvements in systolic and diastolic blood pressure (P < .0001), fasting insulin (P < .0001), total cholesterol (P = .0007), and triglyceride levels (P < .0001) were seen after surgery irrespective of baseline BMI class. Mean albumin levels remained normal despite significant caloric restriction and weight loss. Conclusions Laparoscopic gastric bypass resulted in improvement or reversal of cardiovascular risk factors and resulted in a decrease in BMI of approximately 37% in all patients, regardless of starting BMI, 1 year after surgery. The timing of surgery for adolescent extreme obesity is an important consideration, because “late” referral for bariatric surgery at the highest of BMI values may preclude reversal of obesity.

Inge, Thomas H.; Jenkins, Todd M.; Zeller, Meg; Dolan, Lawrence; Daniels, Stephen R.; Garcia, Victor F.; Brandt, Mary L.; Bean, Judy; Gamm, Kimberlee; Xanthakos, Stavra A.

2010-01-01

65

Is the Caribbean plate subducting underneath Hispaniola? Preliminary results from Caribe Norte wide-angle seismic experiment  

NASA Astrophysics Data System (ADS)

A 200 km long, wide-angle seismic refraction transect was collected in the spring of 2009, across the widest part of the Muertos compressive margin (longitude 69°W). The transect was designed to test the hypothesized subduction of the Caribbean plate’s interior beneath the eastern Greater Antilles island arc. Shots were fired every 90 seconds from the R/V Hesperides’ 3850 cubic inches water-gun array, which, towed at 5 knots, resulted in a shot spacing of ~ 230 m. The seismic signal was recorded by 5 ocean-bottom seismometers deployed at distances varying from 25 to 50 km. Gravity, bathymetry and magnetic data were also acquired along that transect. Published and reprocessed reflection seismic lines nearby provided an initial model of the sediment column and on the pattern of upper crustal reflectors. Preliminary results of a 2-D forward ray-tracing model have enabled us to outline the broad-scale crustal structure across the Muertos margin. The Caribbean oceanic slab shows considerable variations in crustal thickness in the Venezuelan basin area (Caribbean plate’s interior). Farther north, the slab is imaged underneath the Muertos margin to about 60 km north of the deformation front and up to 19 km depth,. A change in crustal p wave velocity at about 60 km from the deformation front (or 70 km from the southern coast of the Dominican Republic) is interpreted to be the boundary between the arc crust and the accretionary prism. Caribbean oceanic crust does not appear to extend farther north. We interpret the results to indicate limited overthrusting of the Caribbean slab in the muertos Trough, rather than subduction.

Llanes Estrada, M.; ten Brink, U. S.; Carbo-Gorosabel, A.; Granja Bruña, J.; Flores, C. H.; Davila, J. M.; Pazos, A.; Quijano, J.

2010-12-01

66

Results of the Refraction\\/Wide Angle Reflection Seismic Experiment in the Southern Rocky Mountains (CD-ROM'99)  

Microsoft Academic Search

During the Continental Dynamics ROcky Mountains Project Experiment (CD-ROM) in 1999, a 950km long refraction\\/wide angle reflection seismic profile was acquired in the southern Rocky Mountains. The seismic line trended south to north from northern New Mexico to central Wyoming. The instrument spacing was 800m along the profile and 10 chemical sources ranging in size from 900kg - 4500kg (100km

H. C. Rumpel; C. M. Snelson; C. Prodehl; G. R. Keller; K. C. Miller

2001-01-01

67

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

68

The carina angle-new geometrical parameter associated with periprocedural side branch compromise and the long-term results in coronary bifurcation lesions with main vessel stenting only.  

PubMed

Background:The two main problems unresolved in coronary bifurcation stenting are periprocedural side branch compromise and higher restenosis at long term. The purpose of this study is to reveal the link between periprocedural side branch compromise and long-term results after main vessel stenting only in coronary bifurcations. Methods:Eighty-four patients formed the study population. The inclusion criteria were good-quality angiograms, with maximal between-branch angle opening, no overlap, permitting accurate angiographic analysis. Carina angle (alpha)-the distal angle between main vessel (MV) before bifurcation and side branch (SB)-was measured pre- and poststenting. Clinical follow-up 9-12 months was obtained with coronary angiography if needed. Results:The patient population was high-risk with 33% diabetics and 84% two- and three-vessel disease. Ninety-five stents were implanted in 92 lesions, with three T-stenting cases. Drug-eluting stents were implanted in 54%. Kissing-balloon (KBI) or sequential inflation was performed in 35%. SB functional closure occurred in 17.4%, with independent predictors alpha < 40 degrees and diameter ratio MB/SB >1.22. After 12+/-4 months there were five myocardial infarctions (6%) and 13 (15%) target lesion revascularization procedures. Independent predictors of major cardiovascular events were carina angle <40 degrees , MB lesion length >8 mm, negative change of between-branch angle, DES usage, and KBI. Conclusions:Smaller carina angle with straightening of MV-main branch from stent implantation in coronary bifurcations predicted higher SB compromise, restenosis, and MACE rates during follow-up of 1 year. PMID:19702678

Gil, Robert J; Vassilev, Dobrin; Formuszewicz, Radoslaw; Rusicka-Piekarz, Teresa; Doganov, Alexander

2009-08-20

69

SGR 0418+5729: A SMALL INCLINATION ANGLE RESULTING IN A NOT SO LOW DIPOLE MAGNETIC FIELD?  

SciTech Connect

The spin-down behaviors of SGR 0418+5729 are investigated. The pulsar spin-down model of Contopoulos and Spitkovsky is applied to SGR 0418+5729. It is shown that SGR 0418+5729 lies below the pulsar death line and its rotation-powered magnetospheric activities may therefore have stopped. The compact star is now spun down by the magnetic dipole moment perpendicular to its rotation axis. Our calculations show that under these assumptions there is the possibility of SGR 0418+5729 having a strong dipole magnetic field, if there is a small magnetic inclination angle. Its dipole magnetic field may be much higher than the characteristic magnetic field. Therefore, SGR 0418+5729 may be a normal magnetar instead of a low magnetic field magnetar.

Tong, H. [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China); Xu, R. X. [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

2012-09-20

70

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

NASA Astrophysics Data System (ADS)

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

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

71

IASI balloon: a nadir looking Fourier transform spectrometer operating in thermal emission for atmospheric sounding  

NASA Astrophysics Data System (ADS)

Atmospheric nadir sounding from space using Fourier transform infrared (FTIR) spectroscopy is becoming a mature technique for both global coverage and good vertical resolution in the troposphere and lower stratosphere. The Infrared Atmospheric Sounding Interferometer (IASI) has been developed by CNES, with Alcatel as the industrial prime contractor, for operation on board the series of European polar orbit meteorological satellites Metop under the overall responsibility of EUMETSAT (first launch end of 2005). In parallel to this international project, a balloon payload has been developed accommodating a Bomem DA2 FTIR instrument operating as a spectro-radiometer based on the 2 blackbody (BB) complex plane calibration technique. The thermal emission spectrum (radiance spectrum) of the atmosphere/surface/cloud system in the region 650-3000 cm-1 is covered at 0.1 cm-1 resolution and 0.4K radiometric precision through co-addition of interferograms (recorded simultaneously) by liquid nitrogen cooled HgCdTe and InSb detectors). A measurement cycle of about 100 s involves hot and cold BB views bracketing the acquisition of nadir looking scenes. Through the combined use of a scan mirror (1st horizontal rotation axis) and azimuth control of the gondola (2nd vertical roation axis), the FTIR can record spectra of fixed targets (IFOV between 600 m and 1000 m on the ground depending on float altitude usually in the range 30 to 40 km) accounting for the usual drift of stratospheric balloons. The performances of the FTIR are discussed in relation to the retrieval of information on the column and/or vertical distribution of tropospheric trace species like H2O, CO2, CO, O3, N2O and others.

Camy-Peyret, C.; Jeseck, P.; Té, Y.; Payan, S.; Evrard, J.

2001-08-01

72

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

73

Results of the Refraction/Wide Angle Reflection Seismic Experiment in the Southern Rocky Mountains (CD-ROM'99)  

NASA Astrophysics Data System (ADS)

During the Continental Dynamics ROcky Mountains Project Experiment (CD-ROM) in 1999, a 950km long refraction/wide angle reflection seismic profile was acquired in the southern Rocky Mountains. The seismic line trended south to north from northern New Mexico to central Wyoming. The instrument spacing was 800m along the profile and 10 chemical sources ranging in size from 900kg - 4500kg (100km spacing) were used. This configuration provided a relatively high resolution data set. The domain of the P-wave model is 950km long, 80km deep and includes the extreme topographic variations between New Mexico (1000m) up to the Continental Divide in Colorado (3500m). At the top of the model the seismic data require two sedimentary layers with thickness vary between 100m near the Arkansas River, Colorado to more than 3km in the North Park Basin, Colorado. Due to the different thickness of the sediments, the Precambrian basement in New Mexico is only 2km deep. In Colorado and Wyoming portions of the line are located on basement exposures intervened by basins up to 3km depth for example the Hanna/Kindt Basin, Wyoming or the North Park Basin, Wyoming. The velocities at the top of the upper crust vary between 5.75km/s and 6.15km/s and increase slowly with depth. Strong lateral velocity variations occour at all depths, some located in the Colorado Mineral Belt region. The lower crust is approximately 10km thick along the profile. The Moho is ca. 45km in New Mexico and deepens to 53km in Colorado. It rises slowly in Wyoming. Indications for the Cheyenne Belt (Archean-Proterozoic transition zone) are identified in both the upper and lower crust.

Rumpel, H. C.; Snelson, C. M.; Prodehl, C.; Keller, G. R.; Miller, K. C.

2001-12-01

74

Results of the CD-ROM project seismic refraction/wide-angle reflection experiment: The upper and middle crust  

NASA Astrophysics Data System (ADS)

During the field experiments of the Continental Dynamics Rocky Mountains Project (CD-ROM) in 1999, a 950 km long refraction/wide-angle reflection seismic profile was acquired in the southern Rocky Mountains. This 950 km long seismic line extended from northern New Mexico to central Wyoming. The sedimentary thickness along the line varies between <100 m near the Arkansas River, Colorado and >3 km in the North Park basin, Colorado. The Precambrian basement in New Mexico is ˜2 km deep. In Colorado and Wyoming, portions of the line are located on basement exposures intervened by basins up to 2.5 km in depth. The velocities at the top of the upper crust vary between 5.75 km/s and 6.15 km/s and increase gradually to (vmax = 6.35 km/s) at 25 km depth. The data suggest that the uppermost Precambrian basement consists of late Proterozoic volcanic and sedimentary rocks or felsic intrusions. The northern Wet Mountains are underlain by high velocities in the upper crust, and Cambrian mafic rocks crop out in these mountains. The Colorado Mineral belt correlates with a broad zone of relatively low velocities in the Precambrian crust indicating the presence of felsic intrusions. The average thickness of the upper crust is 20 km in the Great Plains and 25 km in the Rocky Mountains region. Strong lateral velocity variations occur in the upper crust. Major vertical velocity steps are prominent at the upper to middle crust. The middle crust velocities increase from 6.60 to 6.75 km/s and its average thickness is ˜10 km.

Rumpel, Hanna-Maria; Prodehl, Claus; Snelson, Catherine M.; Keller, G. Randy

75

In-flight Performance and Initial Results of Plasma Energy Angle and Composition Experiment (PACE) on SELENE (Kaguya)  

NASA Astrophysics Data System (ADS)

MAP-PACE (MAgnetic field and Plasma experiment—Plasma energy Angle and Composition Experiment) on SELENE (Kaguya) has completed its ˜1.5-year observation of low-energy charged particles around the Moon. MAP-PACE consists of 4 sensors: ESA (Electron Spectrum Analyzer)-S1, ESA-S2, IMA (Ion Mass Analyzer), and IEA (Ion Energy Analyzer). ESA-S1 and S2 measured the distribution function of low-energy electrons in the energy range 6 eV-9 keV and 9 eV-16 keV, respectively. IMA and IEA measured the distribution function of low-energy ions in the energy ranges 7 eV/q-28 keV/q and 7 eV/q-29 keV/q. All the sensors performed quite well as expected from the laboratory experiment carried out before launch. Since each sensor has a hemispherical field of view, two electron sensors and two ion sensors installed on the spacecraft panels opposite each other could cover the full 3-dimensional phase space of low-energy electrons and ions. One of the ion sensors IMA is an energy mass spectrometer. IMA measured mass-specific ion energy spectra that have never before been obtained at a 100 km altitude polar orbit around the Moon. The newly observed data show characteristic ion populations around the Moon. Besides the solar wind, MAP-PACE-IMA found four clearly distinguishable ion populations on the dayside of the Moon: (1) Solar wind protons backscattered at the lunar surface, (2) Solar wind protons reflected by magnetic anomalies on the lunar surface, (3) Reflected/backscattered protons picked-up by the solar wind, and (4) Ions originating from the lunar surface/lunar exosphere.

Saito, Yoshifumi; Yokota, Shoichiro; Asamura, Kazushi; Tanaka, Takaaki; Nishino, Masaki N.; Yamamoto, Tadateru; Terakawa, Yuta; Fujimoto, Masaki; Hasegawa, Hiroshi; Hayakawa, Hajime; Hirahara, Masafumi; Hoshino, Masahiro; Machida, Shinobu; Mukai, Toshifumi; Nagai, Tsugunobu; Nagatsuma, Tsutomu; Nakagawa, Tomoko; Nakamura, Masato; Oyama, Koh-Ichiro; Sagawa, Eiichi; Sasaki, Susumu; Seki, Kanako; Shinohara, Iku; Terasawa, Toshio; Tsunakawa, Hideo; Shibuya, Hidetoshi; Matsushima, Masaki; Shimizu, Hisayoshi; Takahashi, Futoshi

2010-07-01

76

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

77

Projectile entry angle determination.  

PubMed

Small angles of projectile entry are difficult to determine in two-dimensional targets or in three-dimensional targets where internal deflection has taken place. This results from the fact that small errors in measurement lead to large errors in the calculation of the sine function used in the estimation of the angular projection of a circle onto an inclined plane at angles of less than 20 degrees from the normal. The use of a bullet tip scale, constructed to the dimensions of the entering projectile, allows a significantly more accurate determination of small angles of entry in targets not subject to stretching. A comparison of the relative error inherent in calculating entry angle using the sine function and measuring the angle using the bullet tip scale demonstrates the suitability of using the tip scale at angles less than 20 degrees and the sine function at entry angles greater than 20 degrees. PMID:3944581

Cashman, P J

1986-01-01

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

Film-cooling from holes with compound angle orientations. Part 2: Results downstream of a single row of holes with 6d spanwise spacing  

NASA Astrophysics Data System (ADS)

Experimental results are presented that describe the development and structure of flow downstream of a single row of film-cooling holes with compound angle orientations. With this configuration, holes are spaced 6d apart in the spanwise direction, inclined at 35 deg with respect to the test surface when projected into the streamwise/normal plane, and inclined at 30 deg with respect to the test surface when projected into the spanwise/normal plane. Results are presented for an injectant to free-stream density ratio near 1.0, and injection blowing ratios from 0.5 to 1.50. Comparisons are made with measurements from two other configurations to determine: (1) the effects of hole angle orientation for constant spanwise hole spacing, and (2) the effects of spanwise hole spacing when the hole angle orientation is maintained constant. Results from the first comparison show that the compound angle injection configuration provides significantly improved film-cooling protection compared to a simple angle configuration for the same spanwise hole spacing, normalized streamwise location x/d, and blowing ratio m, for x/d less than 30 when m = 0.50 and for x/d less than 60 when m = 1.0 and 1.5. At x/d greater than 60, spanwise-averaged adiabatic effectiveness data downstream of the two configurations generally cover about the same range. Results from the second comparison show that spanwise-averaged effectiveness values are 20 to 39 percent higher when 6d spanwise hole spacing is employed compared to 7.8d spanwise hole spacing for the same m and x/d, for x/d less than 60. When plotted in bar-eta/m versus Xl/s coordinates, spanwise-averaged film effectiveness data measured downstream of one and two rows of holes from all injection configurations tested show a reasonable collapse. For m values between 1 and 3, spanwise-averaged iso-energetic Stanton number ratios measured just downstream of one row of holes are lower than results measured just downstream of two rows of holes, which evidences greater mixing and higher turbulence levels when the injectant emerges from two rows of holes.

Ligrani, P. M.; Wigle, J. M.; Jackson, S. W.

1994-05-01

80

Calibration Plans for the Multi-angle Imaging SpectroRadiometer (MISR)  

Microsoft Academic Search

The EOS Multi-angle Imaging SpectroRadiometer (MISR) will study the ecology and climate of the Earth through acquisition of global multi-angle imagery. The MISR employs nine discrete cameras, each a push-broom imager. Of these, four point forward, four point aft and one views the nadir. Absolute radiometric calibration will be obtained pre-flight using high quantum efficiency (HQE) detectors and an integrating

C. J. Bruegge; V. G. Duval; N. L. Chrien; D. J. Diner

1993-01-01

81

Monitoring regional vegetation change using reflectance measurements from multiple solar zenith angles.  

PubMed

Many traditional models of vegetation canopy reflectance have commonly used one of two approaches. Either the canopy is assumed to consist of discrete objects of known reflectance and geometric-optics are then used to calculate shading effects, or, as in the turbid medium approach, the canopy is treated as a horizontally homogeneous layer of small elements of known optical properties and radiative transfer theory is used to calculate canopy reflectance. This paper examines the effect of solar zenith angle on the reflectance of red and near-infrared radiation from forests using a combination of these modelling approaches. Forests are first modelled as randomly spaced eucalypt crowns over a homogeneous understorey and the fractional coverage of four components: shaded and sunlit canopy and shaded and sunlit understorey are calculated. Reflectance from each fraction is then modelled for a range of solar zenith angles using the Verhoef SAIL model. The overall scene reflection as seen by a nadir viewing satellite sensor is compared for three forest types representing a gradient of crown density from open dry grassy woodlands to dense wetter closed forest with an understorey of mesophytic plants. Modelled trends in scene reflectance change are consistent with aircraft measurements carried out at three different solar zenith angles. Results indicate that an increase in both tree density and solar zenith angle leads to an increase in the dominance of shaded components. In the visible band, both the sparsely treed woodland and the medium density dry forest show similar trends to that predicted by a turbid medium model, however, the wet forest shows a less rapid decrease in reflectance with solar zenith angle. In the near-infrared band, as tree density increases from woodland to wet forest, overall scene reflectance shows increased departure from that modelled using the traditional assumption of smooth homogeneous canopies, changing from an increase with solar zenith angle for the woodland to a decrease with solar zenith angle for the forest types. PMID:11697672

Russell, M

2001-09-01

82

Peculiarities of backscattering in multifrequency nadir probing of the sea surface  

NASA Astrophysics Data System (ADS)

Backscattering of centimeter electromagnetic waves during nadir probing of the sea surface is considered in an approximation of the Kirchoff method and a two-scale model of the scattering surface. A model of the effective reflection coefficient is developed under the assumption of the specified roughness spectrum model, and the coefficients for Ku (0.021 m), C (0.055 m), and S (0.09 m) bands are calculated. The dependence of the backscattering cross section on the wind speed, wind fetch, and the height of the swell are numerically investigated. The proximity of the numerical estimates and the experimental data is demonstrated. The dependence of the difference of two cross sections on the wind speed or on one of the backscattering cross sections is analyzed in dual-frequency measurements. It is shown that the numerical model made it possible to describe the nonmonotonic behavior of the difference cross section for the Ku-C and Ku-S pairs for the first time. The developed effective reflection coefficient model made it possible to predict in the numerical experiment the behavior of the difference cross section of a new frequency pair (C and S) for which in situ measurements have not yet been performed.

Karaev, V. Yu.; Kanevsky, M. B.; Meshkov, E. M.

2012-12-01

83

Direct estimate of methane radiative forcing by use of nadir spectral radiances.  

PubMed

Direct determination of the radiative forcing of trace gases will be made possible by use of the next generation of nadir-looking spaceborne instruments that provide measurements of atmospheric radiances in the infrared spectral range with improved spectral and spatial resolution. An inversion statistical method has thus been developed and applied to the direct determination of the radiative forcing of methane, based on such instruments as the Fourier-transform Interferometric Monitor for Greenhouse Gases launched onboard the Japanese Advanced Earth Observing Satellite in 1996 and the Infrared Atmospheric Sounding Interferometer planned for the European polar platform Meteorological Operational Satellite in 2000. The method is based on simple statistical laws that directly relate the measured radiances to the radiative forcing by use of an a priori selection of appropriate spectral intervals and global modeling of methane spatial variations. This procedure avoids the use of an indirect determination based on an inversion process that requires precise knowledge of the methane vertical profiles throughout the troposphere. The overall accuracy and precision of this new algorithm are studied, and interfering gases and instrumental characteristics are taken into account. It is shown that radiative forcing can be determined at high horizontal spatial resolution with a precision better than 7% in cloud-free conditions and with well-known surface properties. PMID:18273258

Chazette, P; Clerbaux, C; Mégie, G

1998-05-20

84

Martian dust clouds : two Martian years of SPICAM UV nadir measurements  

NASA Astrophysics Data System (ADS)

SPICAM instrument onboard Mars Express has been successfully operated for over two Martian years (MY 27 and MY 28). UV measurements (200-310 nm) in the nadir mode allowed to register presence of mineral dust and to build spatio-temporal dust distribution maps. The absorbing properties of the Martian dust in the UV permitted easily to separate the observed ice and dust clouds. The following dust optical parameters were used in this paper: single scattering albedo w=0.64 ± 0.04 and asymmetry factor g = 0.86 ± 0.03 at 300 nm and w=0.6 ± 0.045 g,=0.88 ± 0.04 at 213 nm [1]. The cold northern spring and summer exhibit relatively low dust loading with dust optical thickness ? =0.1-0.5 while the warmer end of southern spring and southern summer is the season of dust storms. The measurements cover two Martian southern summers. At this time the background dust loading increased up to ? =1-1.5. The regional dust storms with much higher intensity were also registered: the October 2005 dust storm with the maximal dust optical thickness ? about 3 and the July 2007 dust storm with ? up to 5. The obtained values of the dust optical thickness show good agreement with the values measured by the two Martian rovers, Spirit and Opportunity. [1]Mateshvili, N. et al. (2007), Adv. Space Res., 40, DOI:10.1016/j.asr.2007.06.028;

Mateshvili, Nina; Mateshvili, Nina; Fussen, Didier; Vanhellemont, Filip; Bingen, Christine; Stapelle, Maxime; Dodion, Jan; Dekemper, Emmanuel; Loodts, Nicolas

85

Poor results after recession of both medial rectus muscles in unilateral small-angle Duane’s syndrome, type I  

Microsoft Academic Search

PurposeTo eliminate an abnormal face turn in unilateral Duane’s syndrome, type I, the medial rectus muscle of the Duane’s eye is commonly recessed. Additional recession of the normal contralateral medial rectus muscle has been advocated in selected cases, although little has been published regarding this technique. We present poor results in a small consecutive series.

Marc F Greenberg; Zane F Pollard

2003-01-01

86

Actual versus apparent within cell wall variability of nanoindentation results from wood cell walls related to cellulose microfibril angle  

Microsoft Academic Search

Hardness and elastic modulus of spruce wood cell walls parallel to their axial direction were investigated by means of nanoindentation.\\u000a In the secondary cell wall layer S2 of individual earlywood and compression wood tracheids, a systematic pattern variability\\u000a was found. Several factors potentially affecting nanoindentation results were investigated, i.e. specimen orientation related\\u000a to the indenter tip, cutting direction during specimen

Johannes Konnerth; Notburga Gierlinger; Jozef Keckes; Wolfgang Gindl

2009-01-01

87

Nadir CD4+, religion, antiretroviral therapy, incidence of type 2 diabetes mellitus, and increasing rates of obesity among black Africans with HIV disease  

PubMed Central

Background: The purpose of this study was to determine the cross-sectional association between some sociodemographic factors and antiretroviral therapy (ART), as well as the incidence and predictors of type 2 diabetes mellitus among Central Africans with human immunodeficiency virus (HIV) disease. Methods: This study had a cross-sectional design and was a prospective analysis of 102 patients with HIV disease (49 on ART versus 53 not on ART) in Kinshasa, Democratic Republic of Congo, between 2004 and 2008. A Cox regression model was used to assess for any relationship between type 2 diabetes and exposure to combination ART without protease inhibitors, after adjusting for known risk factors for type 2 diabetes, nadir CD4 and CD8 levels, viral load, marital status, and religion. Results: Unexpectedly elevated rates of smoking, excess alcohol intake, and ART-related total, abdominal, and peripheral obesity were observed in our study group of HIV patients. At the end of follow-up, five patients were diagnosed with type 2 diabetes (incidence rate 4.9%, 9.8 per 1000 person-years). Univariate risk factors for type 2 diabetes were male gender (relative risk [RR] 1.1, 95% confidence interval [CI] 1.01–1.4; P = 0.019), traditional religion versus new charismatic religion (RR 1.1, 95% CI 1.01–1.3; P = 0.046), exposure to ART (RR 1.1, 95% CI 1.002–1.3; P = 0.034), and single status (RR 6.2, 95% CI 1.5–15; P = 0.047). In multivariate analysis, strong significant independent predictors of type 2 diabetes were belonging to a traditional religion (HR 2.1, 95% CI 1.1–4.2; P = 0.036) and a relative increase in nadir CD4 cell count (beta coefficient 0.003; P < 0.0001). Conclusion: ART-related obesity and type 2 diabetes are becoming increasing problems in Central Africans with HIV disease. A relative increase in nadir CD4 count and traditional religion status appear to be the strongest independent predictors of type 2 diabetes.

Mandina Ndona, Madone; Longo-Mbenza, Benjamin; Wumba, Roger; Tandu Umba, Barthelemy; Buassa-bu-Tsumbu, Baudouin; Mbula Mambimbi, Marcel; Wobin, Thaddee Odio; Mbungu Fuele, Simon

2012-01-01

88

Adaptive angle tracking  

Microsoft Academic Search

Angle tracking with phased array antennas in an external noise environment was studied. While the results of this study are applicable generally to arrays of sensors for measuring the angle of arrival of incident radiation, the emphasis in the simulation portion of the study was placed on radar arrays operating in a jamming environment. This problem is important in a

L. E. Brennan; I. S. Reed

1975-01-01

89

Climatology of Ozone on Mars from SPICAM/MEX UV/IR Nadir Measurements  

NASA Astrophysics Data System (ADS)

The european mission Mars Express arrived at Mars in January 2004, during Mars's late northern winter. On board, the dual UV/IR spectrometer SPICAM is dedicated to monitor the martian atmosphere, and has recorded spectra for more than a full martian year. We analyse spectra of the backscattered solar light from SPICAM UV spectrometer in the [110--320] nm range. They were recorded on the day side in a nadir geometry (downward looking mode) where the surface of Mars is observed through the atmosphere. Some of these spectra show a strong absorption band around 250 nm, which is the spectral signature of ozone in the UV. The dataset coverage in season and latitude is variable, depending on observational and technical constrains. Strong spatial and temporal variations in the ozone column-density are observed. At high latitudes of both hemispheres, ozone seems to be present at fall, winter and early spring, to disappear during the spring, and to be totally absent during the summer. We discuss the comparison with predictions from the three-dimensional distribution of ozone computed by the General Circulation Model (GCM) described by Lefevre et al, 2004.Except in a few circumstances, the observed behaviour is well captured by the model, which will allow to calculate and predict other parameters not easy to measure. Even when ozone is found at its maximum value, it is still 200-300times less than on Earth, allowing harmful UV solar radiation to reach the ground. In the infrared, SPICAM is able to measure O2 emission at 1.27 ?m and water vapor at 1.38 ?m. We explore the correlation between H2O and ozone distributions and their implications on the martian photochemisty.

Perrier, S.; Bertaux, J.; Lefèvre, F.; Lebonnois, S.; Montmessin, F.; Fedorova, A.; Korablev, O.

2006-12-01

90

AcrySof phakic angle-supported intraocular lens for the correction of high to extremely high myopia: one-year follow-up results  

PubMed Central

AIM To assess the safety, efficacy and predictability of the AcrySof phakic angle-supported intraocular lens (IOL) (Alcon Inc., U.S.A.) for correction of high-to-extremely high myopia in adults. METHODS In this prospective study performed in Tianjin Medical University Eye Center & College of Optometry, Tianjin, China, 25 eyes of 13 patients were implanted with AcrySof phakic angle-supported IOLs and followed for 1 year postoperatively. Preoperative manifest refractive sphere was (-12.08±2.44) diopters (D) and cylinder was (-1.35±0.62)D. Visual acuity, predictability and stability of manifest refraction spherical equivalent (MRSE), adverse events, and endothelial cell density were analyzed during 1-year of follow-up. RESULTS After 1 year of follow-up, no eyes lost?1 line (best spectacle-corrected visual acuity)BSCVA; an uncorrected visual acuity (UCVA) of 20/20 or better was achieved in 60% of eyes; 100% had an UCVA of 20/40 or better; a BSCVA of 20/30 or better was achieved by 100% of eyes; 84% had a BSCVA of 20/20 or better. The overall mean percentage change in endothelial cell density 1 year after surgery was (-0.27±3.60)%. Two eyes (8%) had increased intraocular pressure (IOP) on the day of surgery. No pupil ovalization, pupillary block, or retinal detachment events were observed. CONCLUSION After 1 year of follow-up, the implantation of AcrySof phakic angle-supported IOL is proved to be safe, effective and predictable with minimal complications in patients with high-to-extremely high myopia. Due to the limitation of visiting time, long-term of clinical investigation is necessary to verify the safety and efficacy of this IOL.

Yang, Rui-Bo; Zhao, Shao-Zhen

2012-01-01

91

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

92

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

93

Disrupted cerebral metabolite levels and lower nadir CD4 + counts are linked to brain volume deficits in 210 HIV-infected patients on stable treatment?  

PubMed Central

Cognitive impairment and brain injury are common in people with HIV/AIDS, even when viral replication is effectively suppressed with combined antiretroviral therapies (cART). Metabolic and structural abnormalities may promote cognitive decline, but we know little about how these measures relate in people on stable cART. Here we used tensor-based morphometry (TBM) to reveal the 3D profile of regional brain volume variations in 210 HIV + patients scanned with whole-brain MRI at 1.5 T (mean age: 48.6 ± 8.4 years; all receiving cART). We identified brain regions where the degree of atrophy was related to HIV clinical measures and cerebral metabolite levels assessed with magnetic resonance spectroscopy (MRS). Regional brain volume reduction was linked to lower nadir CD4 + count, with a 1–2% white matter volume reduction for each 25-point reduction in nadir CD4 +. Even so, brain volume measured by TBM showed no detectable association with current CD4 + count, AIDS Dementia Complex (ADC) stage, HIV RNA load in plasma or cerebrospinal fluid (CSF), duration of HIV infection, antiretroviral CNS penetration-effectiveness (CPE) scores, or years on cART, after controlling for demographic factors, and for multiple comparisons. Elevated glutamate and glutamine (Glx) and lower N-acetylaspartate (NAA) in the frontal white matter, basal ganglia, and mid frontal cortex — were associated with lower white matter, putamen and thalamus volumes, and ventricular and CSF space expansion. Reductions in brain volumes in the setting of chronic and stable disease are strongly linked to a history of immunosuppression, suggesting that delays in initiating cART may result in imminent and irreversible brain damage.

Hua, Xue; Boyle, Christina P.; Harezlak, Jaroslaw; Tate, David F.; Yiannoutsos, Constantin T.; Cohen, Ron; Schifitto, Giovanni; Gongvatana, Assawin; Zhong, Jianhui; Zhu, Tong; Taylor, Michael J.; Campbell, Thomas B.; Daar, Eric S.; Alger, Jeffry R.; Singer, Elyse; Buchthal, Steve; Toga, Arthur W.; Navia, Bradford; Thompson, Paul M.

2013-01-01

94

Critical Angle  

NSDL National Science Digital Library

This website from the Exploratorium provides a demonstration of total internal reflection. The activity uses a fish aquarium to illustrate how a transparent material like water can act as a reflector. The site provides a thorough description of what to do, an explanation of what is happening, including the critical angle, and examples of its applications to optical fibers.

2008-06-23

95

Results on Subcritical One-Phase Coaxial Jet Spread Angles and Subcritical to Supercritical Acoustically Forced Coaxial Jet Dark Core Lengths (Preprint).  

National Technical Information Service (NTIS)

An investigation of the behavior of N2 gas-gas shear coaxial jet spread angles in conjunction with a comprehensive N2 shear coaxial jet dark core length analysis is presented. For the one-phase coaxial jet spread angle study, a total of 6 cases, correspon...

B. Chehroudi D. Talley I. A. Leyva J. I. Rodriguez

2008-01-01

96

A Waveform Model for Near-Nadir Radar Altimetry Applied to the Cassini Mission to Titan  

Microsoft Academic Search

The radar altimeter of the Cassini mission to Titan operates in a transition region between pulse- and beam-limited conditions. Due to the specific observation geometry, low values of mispointing angle have been found to significantly affect altimeter impulse response (IR). This involves a nonconventional formulation of the system response which is the main goal of this paper. An analytical model

Giovanni Alberti; Luca Festa; Claudio Papa; Guido Vingione

2009-01-01

97

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

98

Measurement and prediction of angle-dependent optical properties of coated glass products: results of an inter-laboratory comparison of spectral transmittance and reflectance  

Microsoft Academic Search

The European Union ADOPT project has been concerned with the accurate determination of the optical properties of coated glass products, describing reliable procedures for angle-dependent measurements and the development of predictive algorithms to enable accurate angle-dependent performance characterisation based upon near-normal values only. An essential element of the ADOPT project was the inter-laboratory comparison of transmittance and reflectance measurements for

M. G. Hutchins; A. J. Topping; C. Anderson; F. Olive; P. van Nijnatten; P. Polato; A. Roos; M. Rubin

2001-01-01

99

Polarization ratio for microwave backscattering from the ocean surface at low to moderate incidence angles  

Microsoft Academic Search

It has become apparent that as the incidence angle increases from nadir, the ratio of the backscattered power for microwave scattering from the ocean surface at horizontal to that at vertical polarization (HH\\/VV) becomes larger than that predicted by standard rough-surface scattering models. Although predictions by models that include the effects of long-wave tilt and hydrodynamic modulation yield some improvement,

Donald R. Thompson; Tanos M. Elfouhaily; Bertrand Chapron

1998-01-01

100

Global Environmental Monitoring With Theeos Multi-angle Imaging Spectroradiometer (MISR)  

Microsoft Academic Search

The MISR instrument will provide a unique opportunity for studying the ecology and climate of the Earth through the acquisition of systematic, global multi-angle imagery in reflected sunlight. MISR employs nine cameras: A nadir camera and two banks of four cameras each pointed forward and aftward along the spacecraft ground track to image the Earth at f30.7, f45.6, f60.0, and

D. J. Diner; C. J. Bruegge; J. V. Martonchik; G. W. Bothwell; L. E. Hovland; K. L. Jones

1991-01-01

101

Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) NASA Mission-of- Opportunity - Overview, Initial Results, and Collaborative Opportunities  

NASA Astrophysics Data System (ADS)

TWINS - Two Wide-angle Imaging Neutral-atom Spectrometers is a NASA Explorer Mission-of-Opportunity that is stereoscopically imaging the Earth's magnetosphere for the first time. TWINS simultaneously images the magnetospheric structure in Energetic Neutral Atoms (ENAs) from 1-100 keV with high angular (˜4°x4°) and time (˜1-minute) resolution. The TWINS Ly-? monitor concurrently measures the geocoronal hydrogen density to aid in ENA analysis while environmental sensors provide contemporaneous measurements of the local charged particle environments. By imaging ENAs with identical instruments from two widely spaced, high-altitude, high-inclination spacecraft, TWINS enables three- dimensional visualization of the large-scale structures and dynamics within the magnetosphere for the first time. As of the summer of 2008, both TWINS instruments are operational and providing stereo imaging of the magnetosphere. This talk briefly summarizes the TWINS mission and instruments, summarizes some of the initial results from the mission, and provides a call for future collaborations with theory, modeling, and other in situ observations. More information about TWINS and access to these data are available at http://twins.swri.edu/. * On behalf of the entire TWINS Team

McComas, D.; Goldstein, J.

2009-05-01

102

Angle performance on optima MDxt  

NASA Astrophysics Data System (ADS)

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

David, Jonathan; Kamenitsa, Dennis

2012-11-01

103

Angle performance on optima MDxt  

SciTech Connect

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

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

2012-11-06

104

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

SciTech Connect

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

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

2012-06-01

105

Prognostic value of PSA nadir {<=}4 ng/mL within 4 months of high-dose radiotherapy for locally advanced prostate cancer  

SciTech Connect

Purpose: To investigate early prostate-specific antigen (PSA) kinetics after high radiation doses of 85 Gy on locally advanced prostate cancer. Methods and Materials: A total of 201 patients were prospectively and consecutively treated with external beam radiotherapy and a brachytherapy boost. Of the 201 patients, 104 received concomitant hormonal therapy on the decision of the referring urologist and were excluded, yielding a study population of 97 patients. The first posttreatment PSA analysis was performed not earlier than 1 month after treatment completion but within the first 4 months, and then every 4 months. Analysis of PSA kinetics included the PSA nadir (nPSA) at values of {<=}4 ng/mL to {<=}0.5 ng/mL. The nPSA at {<=}4 ng/mL within 4 months (nPSA {<=}4/4m) was the variable of interest. Results: We established highly significant associations between an nPSA of {<=}1 and {<=}0.5 ng/mL and the nPSA {<=}4/4m (p <0.0001). A hazard ratio of 0.33 (95% Confidence Interval (CI), 0.12-0.91) underlined the lower risk of recurrence related to nPSA {<=}4/4m achievement (p = 0.033). Using time-dependent covariate models for patients who did not reach an nPSA {<=}4/4m, an nPSA of {<=}1 ng/mL remained without prognostic significance (p = 0.06). However, for patients who reached an nPSA {<=}4/4m, an nPSA of {<=}1 ng/mL did significantly improve the prognosis (p <0.001), but much later after treatment. The same analysis was repeated for nPSA {<=}0.5 ng/mL with similar conclusions as when nPSA {<=}4/4m was obtained (p <0.01). Conclusion: The nPSA {<=}4/4m has been demonstrated to be a significant predictor of biochemical no evidence of disease after high radiation doses of 85 Gy. Its major advantage is that it was available earlier than the other nadirs.

Nickers, Philippe [Department of Radiation Oncology, University Hospital of Liege, Liege (Belgium)]. E-mail: philippe.nickers@skynet.be; Albert, Adelin [Department of Biostatistics, University Hospital of Liege, Liege (Belgium); Waltregny, David [Department of Urology, University Hospital of Liege, Liege (Belgium); Deneufbourg, Jean-Marie [Department of Radiation Oncology, University Hospital of Liege, Liege (Belgium)

2006-05-01

106

What's the Angle?  

NSDL National Science Digital Library

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

History, American M.; University, Rice

2002-01-01

107

Indications of A Valley-like Structure In The Chalk Surface Below An Esker Located On Zealand, Denmark; Results From A Shallow Wide-angle Seismic Survey  

NASA Astrophysics Data System (ADS)

The seismic velocity structure is investigated below an esker located just south-west of Roskilde Fjord, Zealand, Denmark. The 150-200 m wide and 20-25 m high esker, which was deposited during the last glaciation of the area, is clearly seen over a dis- tance of at least 3 km. The esker is part of larger, north-south striking esker system. The flow direction of the melting water, which led to the deposition of the esker, is be- lieved to have been from south to north. The main purpose of the seismic experiment is to investigate if the sub-glacial melting water caused erosion and valley formation in the upper part of the underlying chalk layers prior to deposition of the esker. A number of wells show that, today, the chalk layers are situated at 10-50 m depth in the vicinity of the study area. The 850 m long wide-angle seismic line used for the study is located in an area where the above ground parts of the esker have been dug away for commercial purposes, and it is oriented perpendicular to the strike direction of the esker. The seismic line was collected in three stages. For each stage, 37 geophones were evenly distributed along a line segment of 140-190 m length. A total of 28 shots were fired into the three receiver arrays. Most of the shots were located inside the re- ceiver arrays, but some of the shots were located up to 200 m away from the nearest geophone in order to gain velocity control of possible refractors down to about 50 m depth. The first results from travel time modelling of the seismic sections indicate that east and west of the esker a refracting interface with velocities of more than 2300 m/s is present below 20-30 m depth. These high-velocity layers form a significant contrast to the uppermost sedimentary strata, which show velocities of 500-2000 m/s, and they are interpreted to be representative of the topmost parts of the chalk. Such a refract- ing layer is not detected directly below the esker. Thus, the chalk surface seems to be located significantly deeper below the esker than east and west thereof. This may be interpreted as a valley structure in the upper part of the chalk formed by erosional processes caused by melting water prior to deposition of the esker.

Nielsen, L.

108

G.S.M.: a Grating Scale Monitor for atmospheric turbulence measurements. I. The instrument and first results of angle of arrival measurements  

Microsoft Academic Search

A better understanding of the behavior of wavefronts perturbed by the atmospheric turbulence is vital for the progress in the High Angular Resolution (H.A.R) observing techniques, namely long baseline interferometry and adaptive optics. A new instrument called G.S.M. was built for the study of spatial and temporal properties of wavefronts by means of angle of arrival fluctuation measurements in two

F. Martin; A. Tokovinin; A. Agabi; J. Borgnino; A. Ziad

1994-01-01

109

Wide Angle SAR Imaging  

Microsoft Academic Search

ABSTRACT We consider imaging strategies for synthetic aperture radar data collections that span a wide angular aperture. Most traditional radar imaging techniques are predicated on the assumption of isotropic point scattering mechanisms, which does not hold for wide apertures. We investigate point scattering center images for narrowband, wide angle data, and consider the effect of limited persistence on the resulting

Randolph L. Moses; Lee C. Potter; Mujdat Cetin

110

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

111

For Peer Review Only Influence of woody elements of a Norway spruce canopy on nadir reflectance simulated by the DART model at very high spatial resolution  

Microsoft Academic Search

A detailed sensitivity analysis investigating the effect of woody elements introduced into the Discrete Anisotropic Radiative Transfer (DART) model on the nadir bidirectional reflectance factor (BRF) for a simulated Norway spruce canopy was performed at a very high spatial resolution (modelling resolution 0.2 m, output pixel size 0.4 m). We used such a high resolution to be able to parameterize

Emmanuel Martin; Lucie Homolová; Raúl Zurita-Milla; Michael E. Schaepman; Radek Pokorný; Jan G. P. W. Clevers; Pavel Cudlín

112

PSA Nadir Is a Significant Predictor of Treatment Failure after High-Intensity Focussed Ultrasound (HIFU) Treatment of Localised Prostate Cancer  

Microsoft Academic Search

ObjectivesTo assess if prostate-specific antigen (PSA) nadir is an independent predictor of treatment failure and disease-free survival after high-intensity focussed ultrasound (HIFU) therapy for localised prostate cancer as defined by the new ASTRO criteria.

Roman Ganzer; Sebastian Rogenhofer; Bernhard Walter; Jens-Claudio Lunz; Martin Schostak; Wolf F. Wieland; Andreas Blana

2008-01-01

113

Analysis of stratospheric NO2 trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations  

NASA Astrophysics Data System (ADS)

The trend in stratospheric NO2 column at the NDACC (Network for the Detection of Atmospheric Composition Change) station of Jungfraujoch (46.5° N, 8.0° E) is assessed using ground-based FTIR and zenith-scattered visible sunlight SAOZ measurements over the period 1990 to 2009 as well as a composite satellite nadir data set constructed from ERS-2/GOME, ENVISAT/SCIAMACHY, and METOP-A/GOME-2 observations over the 1996-2009 period. To calculate the trends, a linear least squares regression model including explanatory variables for a linear trend, the mean annual cycle, the quasi-biennial oscillation (QBO), solar activity, and stratospheric aerosol loading is used. For the 1990-2009 period, statistically indistinguishable trends of -3.7 ± 1.1% decade-1 and -3.6 ± 0.9% decade-1 are derived for the SAOZ and FTIR NO2 column time series, respectively. SAOZ, FTIR, and satellite nadir data sets show a similar decrease over the 1996-2009 period, with trends of -2.4 ± 1.1% decade-1, -4.3 ± 1.4% decade-1, and -3.6 ± 2.2% decade-1, respectively. The fact that these declines are opposite in sign to the globally observed +2.5% decade-1 trend in N2O, suggests that factors other than N2O are driving the evolution of stratospheric NO2 at northern mid-latitudes. Possible causes of the decrease in stratospheric NO2 columns have been investigated. The most likely cause is a change in the NO2/NO partitioning in favor of NO, due to a possible stratospheric cooling and a decrease in stratospheric chlorine content, the latter being further confirmed by the negative trend in the ClONO2 column derived from FTIR observations at Jungfraujoch. Decreasing ClO concentrations slows the NO + ClO ? NO2 + Cl reaction and a stratospheric cooling slows the NO + O3 ? NO2 + O2 reaction, leaving more NOx in the form of NO. The slightly positive trends in ozone estimated from ground- and satellite-based data sets are also consistent with the decrease of NO2 through the NO2 + O3 ? NO3 + O2 reaction. Finally, we cannot rule out the possibility that a strengthening of the Dobson-Brewer circulation, which reduces the time available for N2O photolysis in the stratosphere, could also contribute to the observed decline in stratospheric NO2 above Jungfraujoch.

Hendrick, F.; Mahieu, E.; Bodeker, G. E.; Boersma, K. F.; Chipperfield, M. P.; De Mazière, M.; De Smedt, I.; Demoulin, P.; Fayt, C.; Hermans, C.; Kreher, K.; Lejeune, B.; Pinardi, G.; Servais, C.; Stübi, R.; van der A, R.; Vernier, J.-P.; Van Roozendael, M.

2012-09-01

114

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

SciTech Connect

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

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

2009-07-01

115

A new stratospheric and tropospheric NO2 retrieval algorithm for nadir-viewing satellite instruments: applications to OMI  

NASA Astrophysics Data System (ADS)

We describe a new algorithm for the retrieval of nitrogen dioxide (NO2) vertical columns from nadir-viewing satellite instruments. This algorithm (SP2) is the basis for the Version 2.1 OMI NO2 Standard Product and features a novel method for separating the stratospheric and tropospheric columns. The approach estimates the stratospheric NO2 directly from satellite data without using stratospheric chemical transport models or assuming any global zonal wave pattern. Tropospheric NO2 columns are retrieved using air mass factors derived from high-resolution radiative transfer calculations and a monthly climatology of NO2 profile shapes. We also present details of how uncertainties in the retrieved columns are estimated. The sensitivity of the retrieval to assumptions made in the stratosphere-troposphere separation is discussed and shown to be small, in an absolute sense, for most regions. We compare daily and monthly mean global OMI NO2 retrievals using the SP2 algorithm with those of the original Version 1 Standard Product (SP1) and the Dutch DOMINO product. The SP2 retrievals yield significantly smaller summertime tropospheric columns than SP1 and are relatively free of modeling artifacts and negative tropospheric NO2 values. In a re-analysis of an INTEX-B validation study, we show that SP2 largely eliminates a ∼20% discrepancy that existed between OMI and independent in situ springtime NO2 SP1 measurements.

Bucsela, E. J.; Krotkov, N. A.; Celarier, E. A.; Lamsal, L. N.; Swartz, W. H.; Bhartia, P. K.; Boersma, K. F.; Veefkind, J. P.; Gleason, J. F.; Pickering, K. E.

2013-02-01

116

A new stratospheric and tropospheric NO2 retrieval algorithm for nadir-viewing satellite instruments: applications to OMI  

NASA Astrophysics Data System (ADS)

We describe a new algorithm for the retrieval of nitrogen dioxide (NO2) vertical columns from nadir-viewing satellite instruments. This algorithm (SP2) is the basis for the Version 2.1 OMI This algorithm (SP2) is the basis for the Version 2.1 Ozone Monitoring Instrument (OMI) NO2 Standard Product and features a novel method for separating the stratospheric and tropospheric columns. NO2 Standard Product and features a novel method for separating the stratospheric and tropospheric columns. The approach estimates the stratospheric NO2 directly from satellite data without using stratospheric chemical transport models or assuming any global zonal wave pattern. Tropospheric NO2 columns are retrieved using air mass factors derived from high-resolution radiative transfer calculations and a monthly climatology of NO2 profile shapes. We also present details of how uncertainties in the retrieved columns are estimated. The sensitivity of the retrieval to assumptions made in the stratosphere-troposphere separation is discussed and shown to be small, in an absolute sense, for most regions. We compare daily and monthly mean global OMI NO2 retrievals using the SP2 algorithm with those of the original Version 1 Standard Product (SP1) and the Dutch DOMINO product. The SP2 retrievals yield significantly smaller summertime tropospheric columns than SP1, particularly in polluted regions, and are more consistent with validation studies. SP2 retrievals are also relatively free of modeling artifacts and negative tropospheric NO2 values. In a reanalysis of an INTEX-B validation study, we show that SP2 largely eliminates an ~20% discrepancy that existed between OMI and independent in situ springtime NO2 SP1 measurements.

Bucsela, E. J.; Krotkov, N. A.; Celarier, E. A.; Lamsal, L. N.; Swartz, W. H.; Bhartia, P. K.; Boersma, K. F.; Veefkind, J. P.; Gleason, J. F.; Pickering, K. E.

2013-10-01

117

Simulation studies for the detection of changes in broadband albedo and shortwave nadir reflectance spectra under a climate change scenario  

NASA Astrophysics Data System (ADS)

Climate forcing by greenhouse gases and aerosols and climate feedbacks from snow, sea-ice, and clouds all significantly impact the future evolution of the climate system's shortwave energy budget. We examine prospects for tracking changes in these forcings and feedbacks using top-of-atmosphere measurements of shortwave reflected radiation. We quantify the extent to which spectral measurements may reduce the time required to detect changes in the climate the climate system with high statistical confidence relative to conventional broadband measurements. We have developed an Observing System Simulation Experiment (OSSE) based on the Community Climate System Model 3.0 for the NASA CLARREO mission and have analyzed forced and unforced simulations of the 21st Century from the Intergovernmental Panel on Climate Change assessments. We find that changes in the simulated nadir spectral reflectance measurements in the visible window and between near-infrared water-vapor overtone channels under clear-sky conditions are detectible faster than the corresponding changes in broadband albedo, with many trends detectible within a five-year satellite mission lifetime. Under all-sky conditions, the superposition of unforced cloud variability on the secular climate trends lengthens the times required for climate-change detection in both the spectral and broadband data. However, migration of the ITCZ and stratus regions can be detected after 16-18 years of observation while broadband albedo measurements require 33-61 years of observation. We find that measurement uncertainty and instrument drift significantly lengthen detection times for broadband albedo and spectral reflectances in window channels but do not have the same effect for spectral measurements in water vapor bands.

Feldman, Daniel R.; Algieri, Chris A.; Collins, William D.; Roberts, Yolanda L.; Pilewskie, Peter A.

2011-12-01

118

Use of PSA nadir to predict subsequent biochemical outcome following external beam radiation therapy for T1-2 adenocarcinoma of the prostate  

Microsoft Academic Search

Purpose. This study assessed the ability of nadir prostate-specific antigen (PSA) to act as an early surrogate for subsequent freedom from biochemical failure following radiation therapy for T1-2 prostatic adenocarcinoma. Methods and materials. A retrospective analysis was performed on the biochemical outcome of 314 consecutive men with T1-2 disease treated by conventional external beam radiation at the Massachusetts General Hospital.

A. L. Zietman; M. K. Tibbs; K. C. Dallow; C. T. Smith; A. F. Althausen; R. A. Zlotecki; W. U. Shipley

1996-01-01

119

Angle closure in younger patients.  

PubMed Central

PURPOSE: Angle-closure glaucoma is rare in children and young adults. Only scattered cases associated with specific clinical entities have been reported. We evaluated the findings in patients in our database aged 40 or younger with angle closure. METHODS: Our database was searched for patients with angle closure who were 40 years old or younger. Data recorded included age at initial consultation; age at the time of diagnosis; gender; results of slit-lamp examination, gonioscopy, and ultrasound biomicroscopy (from 1993 onward); clinical diagnosis; and therapy. Patients with previous incisional surgery were excluded, as were patients with anterior chamber proliferative mechanisms leading to angle closure. RESULTS: Sixty-seven patients (49 females, 18 males) met entry criteria. Mean age (+/- SD) at the time of consultation was 34.4 +/- 9.4 years (range, 3-68 years). Diagnoses included plateau iris syndrome (35 patients), iridociliary cysts (8 patients), retinopathy of prematurity (7 patients), uveitis (5 patients), isolated nanophthalmos (3 patients), relative pupillary block (2 patients), Weill-Marchesani syndrome (3 patients), and 1 patient each with Marfan syndrome, miotic-induced angle closure, persistent hyperplastic primary vitreous, and idiopathic lens subluxation. CONCLUSION: The etiology of angle closure in young persons is different from that in the older population and is typically associated with structural or developmental ocular anomalies rather than relative pupillary block. Following laser iridotomy, these eyes should be monitored for recurrent angle closure and the need for additional laser or incisional surgical intervention.

Chang, Brian M; Liebmann, Jeffrey M; Ritch, Robert

2002-01-01

120

Angles of Reflection  

NSDL National Science Digital Library

This interactive simulation shows what happens to light when it hits a mirror. The simluation allows the user to change the angle of the incoming or incident light wave and see the corresponding reflected angle.

Davidson, Michael W.; Tchourioukanov, Kirill I.

2006-06-15

121

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

122

Aspect and Deviation Angle.  

National Technical Information Service (NTIS)

The purpose of this paper is twofold: first, an attempt is made to define aspect angle and deviation angle in a logical and acceptable manner; second, a graphical calculator is supplied in the hope that it will make the calculation of these angles so simp...

T. A. Croft

1964-01-01

123

Space-nadir observations of formaldehyde columns in the 1995-2008 period and their use for inferring NMVOC emissions through inverse modelling.  

NASA Astrophysics Data System (ADS)

Non-methane volatile organic compounds (NMVOCs) of both natural and anthropogenic origin play an important role in the formation of tropospheric ozone. Despite recent efforts to improve existing databases of NMVOC emissions, large uncertainties still remain mainly due to the diversity of the sources and the complexity of the mechanisms involved. Satellite observations of formaldehyde (CH2O) provide useful information to test and improve bottom-up inventories of NMVOC emissions because CH2O is an intermediate product in the oxidation of a large number of NMVOCs and its lifetime is only a few hours. Since 1995, global distributions of CH2O columns have been retrieved from the GOME, SCIAMACHY, OMI and GOME-2 UV-Vis nadir sounders. The retrieval of CH2O by differential absorption spectroscopy (DOAS) is challenging mainly due to the overall faintness of the CH2O signal, but also due to uncertainties in the calculation of air mass factors. To ensure the coherence of long time series of observations based on the combination of different satellite sounders, retrieval settings must be homogenized while taking into account instrumental specificities and eventual limitations of each sounder. Currently, one of the main limitations of the CH2O retrieval from UV-Vis satellites is the random error of the slant column. For single pixels, this error dominates the other sources of uncertainty. It can be reduced by averaging a large number of observations and to this regard, new instruments like OMI and GOME-2, which offer a much better global coverage of the earth, have the capacity to improve the statistics on the CH2O columns and to allow for more selective cloud screening. Recent achievements but also problems and limitations of the currently available sounders are highlighted. This points to the need for improved satellite instruments, both from LEO and GEO orbital configurations. We finally illustrate the potential of satellite CH2O observations for the inverse modelling of NMVOCs emissions, based on the use of the IMAGESv2 global tropospheric chemistry transport model. Results are shown for biogenic and pyrogenic emissions of VOCs. Anthropogenic emissions are currently more difficult to constrain because of the low signal to noise ratio of the CH2O columns in polluted regions. We discuss the interest and potential of combining CH2O observations with glyoxal measurements from the same sensors.

de Smedt, I.; van Roozendael, M.; Lerot, C.; Müller, J.-F.; Stavrakou, T.; Kurosu, T.; Wittrock, F.

2009-04-01

124

Evaluation of split-window and dual-angle correction methods for land surface temperature retrieval from Envisat/Advanced Along Track Scanning Radiometer (AATSR) data  

NASA Astrophysics Data System (ADS)

Land surface temperature (LST) can be derived from thermal infrared remote sensing data provided that atmospheric and emissivity effects are corrected for. In this paper, two correction methods were evaluated using a database of ground LST measurements and concurrent Envisat/Advanced Along Track Scanning Radiometer (AATSR) data. They were the split-window (SW) method, which uses two channels at 11 and 12 ?m, and the dual-angle (DA) method, using one single channel (11 ?m) at two observation angles (close to nadir and around 55° forward). The ground LST measurements were performed in a large, flat, and thermally homogeneous area of rice fields during the summers of 2002-2005, when the crop showed full vegetation cover. A total of 23 concurrences of ground measurements and AATSR data were obtained. Results showed that the SW algorithms worked satisfactorily provided that the characteristics of the area are correctly prescribed, either through the classification of the land cover type and vegetation cover fraction or with the surface emissivity. In this case the AATSR-derived LSTs agreed with the ground LSTs within ±1.0°C for all the data of the comparison, with negligible average bias and a standard deviation of 0.5°C. The DA algorithms were less accurate than the SW algorithms for the data used in this study, yielding standard deviations of 1.0°C.

Coll, CéSar; Caselles, Vicente; Galve, Joan M.; Valor, Enric; Niclòs, Raquel; SáNchez, Juan M.

2006-06-01

125

Meridional distribution of CH 3C 2H and C 4H 2 in Saturn’s stratosphere from CIRS\\/Cassini limb and nadir observations  

Microsoft Academic Search

Limb and nadir spectra acquired by Cassini\\/CIRS (Composite InfraRed Spectrometer) are analyzed in order to derive, for the first time, the meridional variations of diacetylene (C4H2) and methylacetylene (CH3C2H) mixing ratios in Saturn’s stratosphere, from 5hPa up to 0.05hPa and 80°S to 45°N. We find that the C4H2 and CH3C2H meridional distributions mimic that of acetylene (C2H2), exhibiting small-scale variations

Sandrine Guerlet; Thierry Fouchet; Bruno Bézard; Julianne I. Moses; Leigh N. Fletcher; Amy A. Simon-Miller; F. Michael Flasar

2010-01-01

126

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

2009-11-25

127

Isopistonic angle for multi-aperture interferometers from isoplanatic angle  

NASA Astrophysics Data System (ADS)

Context: Extending the potential of multi-aperture telescopes toward the higher magnitudes necessary for extragalactic science needs an off-axis reference source to cophase the interferometric array. Aims: The off-axis reference star and the science source must be within the isopistonic angle, and evaluating this parameter is crucial for estimating the potential of long-baseline interferometers for faint sources, differential astrometry, and phase-reference imaging. Methods: We derived an analytical method of deducing the isopistonic angle from the standard atmospheric optical parameters, and used a full description of the atmospheric turbulence to validate numerical integrations. Results: We used the analytical expression for the isopistonic angle for predictions concerning the VLT, Keck, and LBT interferometers, as well as for an array of small apertures in the Antarctica site Dome C, indicating that is might be a unique site on earth for interferometric observations of faint sources.

Elhalkouj, T.; Ziad, A.; Petrov, R. G.; Lazrek, M.; Elazhari, Y.; Benkhaldoun, Z.

2008-01-01

128

PFS-MEX nadir observations at 4.3 um in the Mars atmosphere with account for non-LTE emissions  

NASA Astrophysics Data System (ADS)

Non-LTE emissions in the Mars atmosphere have been observed at different wavelength from spacecrafts and ground-based instruments. Since these features are originated at high atmospheric altitudes, most of the observations have been taken at limb (Maguire et al., 2002; Formisano et al., 2006). However, also in a nadir geometry these features are relevant, and recently, an averaged spectra obtained by co-adding 1680 single spectra taken by the Planetary Fourier Spectrometer (PFS) on board Mars Express has been successfully compared to a theoretical non-LTE model (Lopez Valverde et al., 2005). Our intent was to build upon that work by analysing in more detail the full 4.3 µm region in PFS nadir observations, characterizing not only the non-LTE emissions but also the contributions from the surface and the lower atmosphere, particularly important in the wings of this spectral band. The ultimate goal is to derive information about the lower atmosphere, the dust optical thickness and the surface albedo at these wavelengths by a proper consideration of the non-LTE contamination.

Piccialli, A.; Palomba, E.; Lopez Valverde, M. A.; Gilli, G.; Grassi, D.; D'Amore, M.; Formisano, V.

129

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

130

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

131

Classification and treatment of prominent mandibular angle.  

PubMed

In Oriental culture, the contour of the mandibular angle is important for feminine facial shape because a woman who has a wide and square face is thought to have had an unhappy life. A prominent mandibular angle, which does not coincide with the natural look, produces a characteristic quadrangle, coarse, and muscular appearance. So Oriental women who have a prominent mandibular angle want to have an ovoid, reduced, and slender face by aesthetic mandibular angle resection. Many satisfactory corrections of a prominent mandibular angle by various operative techniques have been reported. But reasonable morphologic classification and treatment were not reported. So we classified prominent mandibular angles into four groups by morphology and operated on the patients according to their classification with different modalities: no square shape but only a reduced gonial angle in the profile view-class I, mild form; severe mandibular angle protrusion with lateral protrusion-class II, moderate form; a definite square-shaped angle (class II) with masseteric hypertrophy-class III, severe form; and combined prominent mandibular angle and chin deformity-class IV, complex form. We use angle ostectomy through the intraoral route alone or with an additional external stab incision for class I. An external stab incision to set up the reciprocating saw is sometimes helpful in class I cases because there is no lateral protrusion of the angle. For class II cases, we use conventional intraoral angle ostectomy only or angle splitting ostectomy with contouring. For class III cases, we use angle splitting ostectomy and contouring with partial masseteric myectomy. In class IV, we use angle ostectomy and additional genioplasty. During 7 years, we have performed 46 cases of mandibular angle resection. Of the mandibular angle resection cases, 19 were class I, 15 were class II, 9 were class III, and 3 were class IV. A total of 42 patients were satisfied with the postoperative results. For reasonable and satisfactory final results, classification according to the mandibular angle shape and suitable treatment according to the classification are essential. PMID:11692255

Kim, S K; Han, J J; Kim, J T

132

Minimum enclosures with specified angles  

NASA Astrophysics Data System (ADS)

Given a convex polygon P, an m-envelope is a convex m-sided polygon that contains P. Given any convex polygon P, and any sequence of m >= 3 angles A equals ((alpha) 1, (alpha) 2, ..., (alpha) m) we consider the problem of computing the minimum area m- envelope for P whose counterclockwise sequence of exterior angles is given by A. We show that such envelopes can be computed in O(nm log m) time. The main result on which the correctness of the algorithm rests is a flushness condition stating that for any locally minimum enclosure with specified angles, one of its sides must be collinear with one of the sides of P.

Mount, David M.; Silverman, Ruth

1993-04-01

133

Magnetic reconnection with large separatrix angles  

SciTech Connect

The authors have made use of incompressible MHD simulations to study the process of magnetic reconnection. They have varied the inflow boundary conditions and the magnetic Reynolds numbers. They study the case of magnetic reconnection with large magnetic separatrix angles. They contrast this with the Petschek reconnection model with small separatrix angles. They show that a large normal magnetic field results in the presence of large separatrix angles in the steady state reconnection condition. They find the separatrix angle depends mainly upon the normal magnetic field component on the inflow boundary. They observe the formation of plasma jets, whose structure can convert magnetic energy into plasma kinetic energy by plasma acceleration and heating.

Yan, M.; Lee, L.C. (Univ. of Alaska, Fairbanks (United States)); Priest, E.R. (Univ. of St. Andrews (United Kingdom))

1993-05-01

134

Relationships Between Lower Extremity Alignment and the Quadriceps Angle  

PubMed Central

Objective To determine the extent to which select lower extremity alignment characteristics of the pelvis, hip, knee, and foot are related to the Q angle. Design Descriptive cohort study design. Setting Applied Neuromechanics Research Laboratory. Participants Two hundred eighteen participants (102 males, 116 females). Assessment of Risk Factors Eight clinical measures of static alignment of the left lower extremity were measured by a single examiner to determine the impact of lower extremity alignment on the magnitude of Q angle. Main Outcome Measures Q angle, pelvic angle, hip anteversion, tibiofemoral angle, genu recurvatum, tibial torsion, navicular drop, and femur and tibia length. Results Once all alignment variables were accounted for, greater tibiofemoral angle and femoral anteversion were significant predictors of greater Q angle in both males and females. Pelvic angle, genu recurvatum, tibial torsion, navicular drop, and femur to tibia length ratio were not significant independent predictors of Q angle in males or females. Conclusions Greater femoral anteversion and tibiofemoral angle result in greater Q angle, with changes in tibiofemoral angle having a substantially greater impact on the magnitude of the Q angle compared with femoral anteversion. As such, the Q angle seems to largely represent a frontal plane alignment measure. As many knee injuries seem to result from a combination of both frontal and transverse plane motions and forces, this may in part explain why Q angle has been found to be a poor independent predictor of lower extremity injury risk.

Nguyen, Anh-Dung; Boling, Michelle C.; Levine, Beverly; Shultz, Sandra J.

2010-01-01

135

Investigation of Lightning Rod Shielding Angle  

NASA Astrophysics Data System (ADS)

This paper studies those parameters affecting the shielding angle of the lightning rod (Franklin Rod) above very tall buildings. It was recommended that the shielding angle of the lightning rod is about 45°?60°. The downward lightning leader is modeled by using discrete line charges to consider the exponential distribution of charges through the downward leader. The voltage condition used by Rizk is used to investigate the inception of the upward lightning leader. Different air conditions (relative air density and air humidity) are considered for more practical simulation. The influences of lightning parameters and lightning rod height on the shielding angle are studied. The results shows that, lightning leader parameters, lightning rod height and ground slope have series effects on the lightning rod shielding angle. Based on the results, a lightning rod shielding angle for shielding design is recommended to decrease the lightning stroke to the lightning rod.

Nayel, Mohamed

136

Casting and Angling.  

ERIC Educational Resources Information Center

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

Smith, Julian W.

137

Progress in phase angle thermography  

NASA Astrophysics Data System (ADS)

Phase angle thermography is basically spatially multiplexed photothermal radiometry. It provides images for remote detection and imaging of damage. For energy deposition one can use external heat sources (e.g., light or convective heating) or internal heat generation (e.g., electric current, microwaves, eddy current, or elastic wave). More complete information about defects is obtained by combining information from external and internal heating methods: Effects of intact thermal structure can be distinguished from defect specific thermal signatures. Our recent results relate to multifrequency excitation allowing for depth profiling from one lock-in-thermography measurement and, additionally, to modulated ultrasound frequency burst phase angle thermography where effects of standing elastic waves are eliminated. This way the applications for nondestructive evaluation become more reliable and faster.

Dillenz, A.; Zweschper, T.; Riegert, G.; Busse, G.

2003-01-01

138

Angle illusion on a picture's surface.  

PubMed

Shapes on picture surfaces are not seen accurately (Arnheim, 1954). In particular, if they depict 3-D forms, angles between lines on a picture surface are misperceived. To test four theories of the misperception, subjects estimated acute and obtuse internal angles of quadrilaterals. Each quadrilateral was shown alone or as part of a drawing of a cube. The drawings showed the tops of the cubes, tilted at various angles around a horizontal axis. This generated different acute and obtuse angles in the drawings. Compared to a quadrilateral on its own, judgments of the acute and obtuse angles in the cube drawings were biased towards 90 degrees . The bias was present over a wide range of intermediate tilts. The results support a perspective convergence theory and run counter to 'Extreme Foreshortening', Gestalt and Cognitive theories. PMID:18534114

Hammad, Sherief; Kennedy, John M; Juricevic, Igor; Rajani, Shazma

2008-01-01

139

Implant Angle Repeatability on Optima MD  

NASA Astrophysics Data System (ADS)

A very sensitive channeling implant has been used to quantify the repeatability of implant angles for the Optima MD over a period exceeding one month. Sensitivity of sheet resistance to variation in vertical and horizontal beam angles was measured for 500 keV P++ at a dose of 5E13 /cm2 near orientations tilt/twist of 0°/0° and 35.26°/0° for (100) wafers. Sensitivity to tilt in the vertical plane at both conditions was at least a 10% change in Rs for a 0.5° change in tilt at a tilt of 0.75° away from the channel (i.e. at 0.75°/0° and 34.5°/0°), where the variation in Rs was linear with tilt. Horizontal angle sensitivity resulted in a 7.5% change in Rs for a 0.5° change in angle, but was less sensitive to smaller angle variation, since Rs varied roughly as a second order function near the channel. Sensitivity to tilt is reduced by about a factor of 3 for implants at 0°/0° compared to 0.75°/0° with a similar response at 35.26°/0° compared to 34.5°/0°. Implants were carried out using wafers from a single boule over a period exceeding one month at the orientation of 0.75°/0°. Angle control was enabled by in-situ measurement and correction of the beam angles in both the vertical and horizontal planes prior to implant. The repeatability of sheet resistance was used to infer the variation in angle. Attributing all Rs variation to be the result of beam angle variation showed that the standard deviation of beam angles for over 30 wafers is 0.03°.

Rathmell, Robert; David, Jonathan; Harris, Mark

2008-11-01

140

Adjustable-angle pipe fitting  

DOEpatents

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

Kronberg, J.W.

1991-01-01

141

Adjustable-angle pipe fitting  

DOEpatents

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

Kronberg, J.W.

1991-12-31

142

Ocular Biometry in Angle Closure  

PubMed Central

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

Razeghinejad, Mohammad Reza; Banifatemi, Mohammad

2013-01-01

143

Deflection Angle and R-Charged Black Holes  

NASA Astrophysics Data System (ADS)

In this paper we consider R-charged black holes with three electrical charges and study deflection angle. We confirmed result of previous study that the black hole charges increased the deflection angle.

Saadat, Hassan

2013-10-01

144

Angle amplifier based on multiplexed volume holographic gratings  

NASA Astrophysics Data System (ADS)

Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of the Bragg compensatory relation between angle and wavelength, this device could be recorded at another wavelength. The design of the angle amplifier recording at the wavelength of 514.2nm for the working wavelength of 632.8nm is described. An optical setup for recording the angle amplifier device is designed and discussed. Experimental results in the photorefractive crystal Fe:LiNbO3 demonstrate the feasibility of the angle amplifier scheme.

Cao, Liangcai; Zhao, Yifei; He, Qingsheng; Jin, Guofan

2008-03-01

145

Test measurements by a BBM of the nadir-looking SWIR FTS aboard GOSAT to monitor CO2 column density from space  

NASA Astrophysics Data System (ADS)

Greenhouse gases Observing SATellite (GOSAT) is a Japanese satellite to monitor column density of greenhouse gases such as carbon dioxide (CO2) and methane (CH4) globally from space. GOSAT will be launched in 2008. The data measured by a GOSAT sensor and ground-based monitoring station data will be used into an atmospheric transport inverse model to identify source/sink amount of CO2 in a sub-continental scale. One of the main GOSAT sensors is a nadir-looking Fourier Transform Spectrometer (FTS), which covers Short Wavelength Infrared (SWIR) region to measure column density of CO2. National Institute for Environmental Studies (NIES) is promoting researches on CO2 and CH4 sensitivity analysis, error analysis, data retrieval algorithm study, ground-based/air-borne validation strategy, and a plan of inverse model study for the SWIR FTS. A Bread-board model (BBM) of the SWIR FTS was built and tested by ground-based and airborne measurements. Several sets of the CO2 and CH4 radiance spectra over rice fields were obtained by the test measurements, and it was confirmed that the airborne measurements with a vibration insulator are effective for onboard measurements. Moreover, several improvement items of BBM have become clear.

Yokota, Tatsuya; Oguma, Hiroyuki; Morino, Isamu; Higurashi, Akiko; Aoki, Tadao; Inoue, Gen

2004-12-01

146

Shapes and Angles  

NSDL National Science Digital Library

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

Nasa

2012-05-08

147

Pitch angle variations in spiral galaxies  

NASA Astrophysics Data System (ADS)

We present a detailed photometric study and measurements of spiral arm pitch angles for a sample of 50 non-barred or weakly barred grand-design spiral galaxies selected from Sloan Digital Sky Survey. In order to find pitch angles, we used a new method based on the window Fourier analysis of their images. This method allows us not only to infer the average pitch angle, but to obtain its value as a function of galactocentric radius as well. Our main results are as follows: (1) Spiral arms of most galaxies cannot be described by a single value of the pitch angle. About 2/3 of galaxies demonstrate pitch angle variations exceeding 20 per cent. In most galaxies in the sample their pitch angle decreases by increasing the distance from the centre. (2) Pitch angle variations correlate with the properties of galaxies - with the shape of the surface brightness distribution (envelope-type or truncated disc), and with the sign of stellar disc colour gradient. (3) More luminous and bright bulges produce more tightly wound spiral arms, that is in agreement with current models for spiral arms formation.

Savchenko, S. S.; Reshetnikov, V. P.

2013-09-01

148

Creation of the ? angle standard for the flat angle measurements  

NASA Astrophysics Data System (ADS)

Angle measurements are based mainly on multiangle prisms - polygons with autocollimators, rotary encoders fo high accuracy and circular scales as the standards of the flat angle. Traceability of angle measurements is based on the standard of the plane angle - prism (polygon) calibrated at an appropriate accuracy. Some metrological institutions have established their special test benches (comparators) equipped with circular scales or rotary encoders of high accuracy and polygons with autocollimators for angle calibration purposes. Nevertheless, the standard (etalon) of plane angle - polygon has many restrictions for the transfer of angle unit - radian (rad) and other units of angle. It depends on the number of angles formed by the flat sides of the polygon that is restricted by technological and metrological difficulties related to the production and accuracy determination of the polygon. A possibility to create the standard of the angle equal to ? rad or half the circle or the full angle is proposed. It can be created by the circular scale with the rotation axis of very high accuracy and two precision reading instruments, usually, photoelectric microscopes (PM), placed on the opposite sides of the circular scale using the special alignment steps. A great variety of angle units and values can be measured and its traceability ensured by applying the third PM on the scale. Calibration of the circular scale itself and other scale or rotary encoder as well is possible using the proposed method with an implementation of ? rad as the primary standard angle. The method proposed enables to assure a traceability of angle measurements at every laboratory having appropriate environment and reading instruments of appropriate accuracy together with a rotary table with the rotation axis of high accuracy - rotation trajectory (runout) being in the range of 0.05 ?m. Short information about the multipurpose angle measurement test bench developed is presented.

Giniotis, V.; Rybokas, M.

2010-07-01

149

Angle closure in younger patients  

Microsoft Academic Search

PurposeAngle-closure glaucoma is rare in children and young adults; only scattered cases associated with specific clinical entities have been reported. We evaluated the findings in patients aged 40 or younger with angle closure in our database.

Robert Ritch; Brian M Chang; Jeffrey M Liebmann

2003-01-01

150

Angle only tracking with particle flow filters  

NASA Astrophysics Data System (ADS)

We show the results of numerical experiments for tracking ballistic missiles using only angle measurements. We compare the performance of an extended Kalman filter with a new nonlinear filter using particle flow to compute Bayes' rule. For certain difficult geometries, the particle flow filter is an order of magnitude more accurate than the EKF. Angle only tracking is of interest in several different sensors; for example, passive optics and radars in which range and Doppler data are spoiled by jamming.

Daum, Fred; Huang, Jim

2011-09-01

151

Predisposing factors for chronic angle-closure glaucoma  

Microsoft Academic Search

Chronic angle-closure glaucoma is the commonest form of glaucoma in Sino–Mongaloid populations. It is an anatomical disorder of the anterior segment of the eye characterised by permanent closure of part of the filtration angle as a result of iris apposition to the trabecular meshwork. Two pathways lead to this condition: recurrent pupillary block and “creeping” angle closure. East or Southeast

John F. Salmon

1999-01-01

152

A Model of Electrowetting, Reversed Electrowetting and Contact Angle Saturation  

Microsoft Academic Search

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

Dan Klarman; David Andelman; Michael Urbakh

2011-01-01

153

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

154

Wide angle reflections in OBC seismic physical model experiment  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

155

Nekrotizan Fasiit: Nadir Bir olgu  

Microsoft Academic Search

Nekrotizan fasiit (NF); deri, subkutan dokular ve fasyalar›n ilerleyici nekrozu ile karakterize, yaflam› tehdit eden bir yumuflak doku enfeksiyonudur. Erken tan› ve tedaviye ramen mor- talite ve morbiditesi yüksektir. On bir yafl›nda erkek hasta sol kolunda bir gün önce baflla- yan flifllik ve ar› yak›nmalar› ile acil polikliniimize baflvurdu. Fizik muayenede sol kolda flifllik, ›s› art›fl› ve pasif hareketlerle ar›

Ayhan Gazi KALAYCI; Emel Gül OKUR

2006-01-01

156

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

Microsoft Academic Search

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

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

2006-01-01

157

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

Microsoft Academic Search

Purpose: Permanent prostate implant brachytherapy (PPI), three-dimensional conformal radiotherapy (3D-CRT), and conformal proton beam radiotherapy (CPBRT) are used in the treatment of localized prostate cancer, although no head-to-head trials have compared these modalities. We studied the biochemical control (biochemical no evidence of disease [bNED]) and prostate-specific antigen (PSA) nadir achieved with contemporary PPI, and evaluated it against 3D-CRT and CPBRT.

Siavash Jabbari; Vivian K. Weinberg; Katsuto Shinohara; Joycelyn L. Speight; Alexander R. Gottschalk; I.-Chow Hsu; Barby Pickett; Patrick W. McLaughlin; Howard M. Sandler; Mack Roach III

2010-01-01

158

The impact of inlet angle and outlet angle of guide vane on pump in reversal based hydraulic turbine performance  

NASA Astrophysics Data System (ADS)

In this paper, in order to research the impact of inlet angle and outlet angle of guide vane on hydraulic turbine performance, a centrifugal pump in reversal is adopted as turbine. A numerical simulation method is adopted for researching outer performance and flow field of turbine. The results show: inlet angle has a crucial role to turbine, to the same flow, there is a noticeable decline for the efficiency and head of turbine with the inlet angle increases. At the best efficiency point(EFP),to a same inlet angle, when the inlet angle greater than inlet angle, velocity circulation in guide vane outlet decreases, which lead the efficiency of turbine to reduce, Contrarily, the efficiency rises. With the increase of inlet angle and outlet angle, the EFP moves to the big flow area and the uniformity of pressure distribution becomes worse. The paper indicates that the inlet angle and outlet angle have great impact on the turbine performance, and the best combination exists for the inlet angle and outlet angle of the guide vane.

Shi, F. X.; Yang, J. H.; Wang, X. H.; Zhang, R. H.; Li, C. E.

2012-11-01

159

Angle Concept Formation in Elementary Age Children  

Microsoft Academic Search

This paper is a review of literature on the child's development of the angle concept. Children have difficulties understanding angles that stem from the lack of salience of the angle in general representations and particular angle situations, the wide variety of particular angle situations, and the fact that there is no single angle concept but rather multiple angle concepts. General

TJ Leone

160

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...

161

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

162

Solar cell angle of incidence corrections  

NASA Astrophysics Data System (ADS)

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.

1995-10-01

163

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

164

Refraction and wide-angle reflection, examples of OBS velocity and depth-prolongation of vertical-reflection in SEISMARMARA  

NASA Astrophysics Data System (ADS)

In the frame of the Turkish-French cooperation on the Marmara Sea after the 1999 Izmit earthquake occurrence on the North Anatolian Fault, the SEISMARMARA survey 2001 was carried out as a multi-method approach of seismic structure and activity. Among its components, a set of 37 OBS of ISV Hokkaïdo were deployed and recovered by the Turkish vessel MTA-Sismik 1. They recorded continuously for the whole duration of the acquisition of multichannel seismic profiles (MCS) that has been operated in two legs (Leg 1 and Leg 2) by the French N/O Nadir of Ifremer. Here we present the first results of modelling proceeds on the two longest E-W lines of Leg 1. The 8100 cu. in. capacity of the 12-airgun array of the French N/O Nadir of Ifremer, and its shooting in single-bubble mode, provided for signal strength, low frequency but also relatively short signal duration. The shooting interval was set at 60 seconds in order to avoid overshooting and water wave disturbance to the late arrivals expected for wide-angle reflections on deep crustal levels. The main regional line, striking E-W along the axis of the North Marmara Through, is 120 km long and has 13 OBS. The corresponding MCS stack with 15-fold coverage obtained at normal incidence with the 4.5 km long 360-channels digital streamer is used for structural constraints for the shallow part in the refraction modelling. It was also shot at 20 seconds interval to give a higher, 45-fold coverage for MCS meant at finer resolution, and the comparison with velocity control given by the streamer recording in shallow water will be used too. In order to assess effects of off-line propagation in this region of strong 3D structural variation, MCS N-S cross-lines can be drawn in as well. An other E-W line along the southern rim of the Trough is modelled, tying in with the Marmara-1 borehole that reached the Upper Cretaceous limestone, the basement to the evolution of the Trough. Basement topography and structure of the lower crust is sampled and modelled by these data sets. In the case of the line on the rim of the Trough, the velocity model can be compared to the MCS which gives a reasonable structural image through the whole crust. On the axial line, new critical constraints are provided on the basement and deep structure across the succession of basins and highs, where the normal-incidence MCS image is complicated by strong multiples and off-line echoes. These results will contribute to the analysis of the structural evolution of the Marmara trough with respect to the North Anatolian Fault, and bring constraints on the depth limits of the seismogenic layer involved in earthquakes to occur in the Marmara sea part of the North Anatolian Fault. Derivation of the velocity structure provides a frame necessary to refine earthquake location procedures in general. More specifically, the analysis of shot data on the 3 components of OBSs, give prime control on the local P and S velocity heterogeneity under the OBS which will be used as input in a fine study of the local earthquakes also recorded on these same OBSs.

Bécel, A.

2003-04-01

165

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

166

Changes in muscular pennation angle after crenotherapy  

PubMed Central

Summary Muscular architecture involves the organization of fibres in the muscle and is one of the most important factors of muscular function. Studies have demonstrated an association with muscular architecture and contraction, with an increase of the pennation angle in muscles. The aim of the study was to evaluate the change of muscular pennation angle after therapy with warm thermal water (crenotherapy). Participants: 45 amateur athletes undertaking different sporting activities; Group A: 30 runners; Group B: 15 swimmers. All the athletes underwent muscular ultrasound and clinical examination before and after the 10 sessions of the thermal protocol. At baseline the groups showed different values of pennation angle (group A = 19.1° ± 3.8° vs group B = 16.7° ± 2.4°; p=0.05). Following the thermal therapy protocol, significant variation of pennation angle was detected at rest in Group A which had significantly lower values than before the treatment (17.5° ± 2.9°; p=0.01). No differences were detected in group B. Conclusions: thermal therapy induced the greatest effect on runners (Group A) as pennation angle at rest was significantly lower after the period of crenotherapy and this variation may be as a result of a smaller muscular contracture.

Brancaccio, Paola; Somma, Florence; Provenzano, Federica; Rastrelli, Luca

2013-01-01

167

Geometric structures on moment-angle manifolds  

NASA Astrophysics Data System (ADS)

A moment-angle complex \\mathscr{Z}_{\\mathscr{K}} is a cell complex with a torus action constructed from a finite simplicial complex {\\mathscr{K}}. When this construction is applied to a triangulated sphere {\\mathscr{K}} or, in particular, to the boundary of a simplicial polytope, the result is a manifold. Moment-angle manifolds and complexes are central objects in toric topology, and currently are gaining much interest in homotopy theory and complex and symplectic geometry. The geometric aspects of the theory of moment-angle complexes are the main theme of this survey. Constructions of non-Kähler complex-analytic structures on moment-angle manifolds corresponding to polytopes and complete simplicial fans are reviewed, and invariants of these structures such as the Hodge numbers and Dolbeault cohomology rings are described. Symplectic and Lagrangian aspects of the theory are also of considerable interest. Moment-angle manifolds appear as level sets for quadratic Hamiltonians of torus actions, and can be used to construct new families of Hamiltonian-minimal Lagrangian submanifolds in a complex space, complex projective space, or toric varieties. Bibliography: 59 titles.

Panov, T. E.

2013-06-01

168

Critical angle in fluorescent polymer optical fibers  

NASA Astrophysics Data System (ADS)

The aim of this work is to analyze the propagation of the emitted light in fluorescent POFs by using the side-illumination technique. In particular, we have studied the angular distribution of the emitted light as a function of the launching angle and of the height of the incident beam. A theoretical model has been developed in order to explain the experimental measurements. A good agreement between the theoretical and the experimental results has been obtained both qualitatively and quantitatively. It is shown that both the theoretical and the experimental critical angles are appreciably higher than the meridional one corresponding to the maximum acceptance angle for a single source placed at the fiber axis. This increase changes the value of several important parameters in the performance of active fibers. The analysis has been performed in polymer optical fibers doped with a conjugated polymer.

Bikandi, I.; Illarramendi, M. A.; Zubia, J.; Arrue, J.; Jiménez, F.; Ayesta, I.; Bazzana, L.

2012-02-01

169

Angle-resolved photoemission from Au(112)  

NASA Astrophysics Data System (ADS)

The angular variations of the spectral positions of peaks in angle-resolved photoemission spectra for Au(112) due to bulk interband transitions have been calculated using a band model for gold which agrees with other optical data. The calculations agree with the experimental results published recently by Heimann et al.

Christensen, N. Egede

1981-08-01

170

Atmospheric neutrino flux measurement using upgoing muons  

Microsoft Academic Search

We report on the first measurement of the flux of upgoing muons resulting from interactions of atmospheric neutrinos in the rock below MACRO. The ratio of the observed to the expected number of events integrated over all nadir angles is 0.73 ± .09stat. ± .06sys. ± .12theor.. The flux of upgoing muons as a function of nadir angle is presented

S. Ahlen; M. Ambrosio; R. Antolini; G. Auriemma; R. Baker; A. Baldini; G. C. Barbarino; B. C. Barish; G. Battistoni; R. Bellotti; C. Bemporad; P. Bernardini; H. Bilokon; V. Bisi; C. Bloise; C. Bower; S. Bussino; F. Cafagna; M. Calicchio; D. Campana; M. Carboni; M. Castellano; S. Cecchini; F. Cei; P. Celio; V. Chiarella; R. Cormack; A. Corona; S. Coutu; G. De Cataldo; H. Dekhissi; C. De Marzo; E. Diehl; I. De Mitri; M. De Vincenzi; A. Di Credico; O. Erriquez; C. Favuzzi; C. Forti; P. Fusco; G. Giacomelli; G. Giannini; N. Giglietto; M. Grassi; P. Green; A. Grillo; F. Guarino; P. Guarnaccia; C. Gustavino; A. Habig; K. Hanson; A. Hawthorne; R. Heinz; J. T. Hong; E. Iarocci; E. Katsavounidis; E. Kearns; S. Kyriazopoulou; E. Lamanna; D. S. Levin; P. Lipari; G. Liu; R. Liu; N. P. Longley; M. J. Longo; Y. Lu; G. Ludlam; G. Mancarella; G. Mandrioli; A. Margiotta-Neri; A. Marin; A. Marini; D. Martello; A. Marzari-Chiesa; M. N. Mazziotta; D. G. Michael; S. Mikheyev; L. Miller; M. Mittelbrunn; P. Monacelli; T. Montaruli; M. Monteno; S. Mufson; J. Musser; D. Nicoló; R. Nolty; S. Nutter; C. Okada; C. Orth; G. Osteria; O. Palamara; S. Parlati; V. Patera; L. Patrizii; R. Pazzi; C. W. Peck; J. Petrakis; S. Petrera; N. D. Pignatano; P. Pistilli; V. Popa; A. Rainó; J. Reynoldson; F. Ronga; A. Sanzgiri; F. Sartogo; C. Satriano; L. Satta; E. Scapparone; K. Scholberg; A. Sciubba; P. Serra-Lugaresi; M. Severi; M. Sitta; P. Spinelli; M. Spinetti; M. Spurio; R. Steinberg; J. L. Stone; L. R. Sulak; A. Surdo; G. Tarlé; V. Togo; V. Valente; C. W. Walter; R. Webb; W. Worstell

1995-01-01

171

Ring magnet firing angle control  

DOEpatents

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 to a particular number each cycle of the main generator voltage wave is synchronized with the smooth AC signal of the phase lock loop. Gates compare the number in the counter with predetermined desired firing angles for each thyratron and with coincidence the proper thyratron is fired at the predetermined firing angle.

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

1975-10-21

172

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

173

Measuring and interpreting contact angles: a complex issue  

Microsoft Academic Search

Low-rate dynamic contact angles of 30 liquids on a FC-725-coated wafer surface were measured by an automated axisymmetric drop shape analysis-profile (ADSA-P). Surprisingly, results indicate that FC-725 behaves differently in some respects from what one would expect for non-polar surfaces: only nine liquids yield essentially constant contact angles whereas the others show slip\\/stick contact angle behaviour. In the worst case,

D. Y. Kwok; C. N. C. Lam; A. Li; A. Leung; R. Wu; E. Mok; A. W. Neumann

1998-01-01

174

Electrowetting: a model for contact-angle saturation  

Microsoft Academic Search

Electrowetting (EW) involves the application of an electric potential across a solid–liquid (SL) interface, which modifies\\u000a the wetting properties of that interface by reducing the SL surface energy and induces a contact-angle change without altering\\u000a either the bulk liquid or solid properties. Reversible contact angles are achieved at low potentials, while the application\\u000a of high potentials results in contact-angle saturation

V. Peykov; A. Quinn; J. Ralston

2000-01-01

175

A new approach of assessing sagittal dysplasia: the W angle.  

PubMed

In orthodontic diagnosis and treatment planning, an accurate antero-posterior measurement of jaw relationships is critically important. Previously described angular and linear measurements can be inaccurate because of their dependency on various factors. The purpose of this study was to introduce a new cephalometric measurement, named the W angle, to assess the sagittal relationship between maxilla and mandible with accuracy and reproducibility. This angle uses three skeletal landmarks--point S, point M, and point G--to measure an angle that indicates the severity and the type of skeletal dysplasia in the sagittal dimension. One hundred and forty-two pre-treatment cephalometric radiographs of patients between the age of 15 and 25 years were selected. They were again subdivided into Classes I, II, and III groups on the basis of Beta angle, Wits appraisal, and ANB angle. The W angle was measured between the perpendicular from point M on S-G line and the M-G line. The mean and the standard deviation for the W angle were calculated. After using the one-way analysis of variance and the Newman-Keuls test, receiver operating characteristics curves were obtained. Results showed that a patient with a W angle between 51 and 56 degrees can be considered to have a Class I skeletal pattern. With an angle less than 51 degrees, patients are considered to have a skeletal Class II relationship and with an angle greater than 56 degrees, patients have a skeletal Class III relationship. PMID:21303811

Bhad, Wasundhara A; Nayak, Subash; Doshi, Umal H

2011-02-08

176

Application of angle-only track to ballistic missile defense  

Microsoft Academic Search

Results are presented of an analysis of angle-only track in a ballistic missile defense (BMD) adjunct role. It is demonstrated that a ballistic trajectory is observable with an angle-only sensor mounted on an observation platform moving on a ballistic trajectory when the proper tracking filter is used to minimize the effects of observational bias. Results are shown on initialization of

L. B. Weiner; T. L. Homsley

1976-01-01

177

Unitarity Triangle Angle Measurements at BaBar  

SciTech Connect

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

Latham, Thomas E.; /SLAC

2005-06-30

178

Penetrating facial injury from angle grinder use: management and prevention  

Microsoft Academic Search

Injuries resulting from the use of angle grinders are numerous. The most common sites injured are the head and face. The high speed disc of angle grinders does not respect anatomical boundaries or structures and thus the injuries produced can be disfiguring, permanently disabling or even fatal. However, aesthetically pleasing results can be achieved with thorough debridement, resection of wound

Lachlan M Carter; Craig J Wales; Iain Varley; Martin R Telfer

2008-01-01

179

What is a Right Angle?  

NSDL National Science Digital Library

You will learn how to identify different kinds of angles. Dates: You begin this activity on October 8th. You must complete it by October 12th. Objective (Goal): As you already learned about different kinds of angles. Now you will practice your knowledge with different websites. Materials: Your worksheet from Ms. O\\'Hara and a pencil. Websites for answering your questions in your worksheet. ------------------------------------- Why ...

Ms. O\\'Hara

2006-10-04

180

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

181

High-resolution slant-angle scene generation and validation of concealed targets in DIRSIG  

NASA Astrophysics Data System (ADS)

Traditionally, synthetic imagery has been constructed to simulate images captured with low resolution, nadir-viewing sensors. Advances in sensor design have driven a need to simulate scenes not only at higher resolutions but also from oblique view angles. The primary efforts of this research include: real image capture, scene construction and modeling, and validation of the synthetic imagery in the reflective portion of the spectrum. High resolution imagery was collected of an area named MicroScene at the Rochester Institute of Technology using the Chester F. Carlson Center for Imaging Science's MISI and WASP sensors using an oblique view angle. Three Humvees, the primary targets, were placed in the scene under three different levels of concealment. Following the collection, a synthetic replica of the scene was constructed and then rendered with the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model configured to recreate the scene both spatially and spectrally based on actual sensor characteristics. Finally, a validation of the synthetic imagery against the real images of MicroScene was accomplished using a combination of qualitative analysis, Gaussian maximum likelihood classification, and the RX algorithm. The model was updated following each validation using a cyclical development approach. The purpose of this research is to provide a level of confidence in the synthetic imagery produced by DIRSIG so that it can be used to train and develop algorithms for real world concealed target detection.

Barcomb, Kris E.; Schott, John R.; Brown, Scott D.; Hattenberger, Timothy J.

2004-10-01

182

A high-sensitivity angle and energy dipersive multichannel electron momentum spectrometer with 2{pi} angle range  

SciTech Connect

A high-sensitivity angle and energy dispersive multichannel electron momentum spectrometer with simultaneous detection in 2{pi} angle range is presented. A newly designed double half wedge and strip anode position-sensitive detector is employed to collect the ionized and scattered electrons passing through a 90 deg. sector, 2{pi} spherical electrostatic analyzer over azimuthal angle range of about 150 deg. for each. Experimental results on argon are presented to exhibit the performance of the spectrometer.

Tian Qiguo; Wang Kedong; Shan Xu; Chen Xiangjun [Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026 (China); Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

2011-03-15

183

Three dimensional thermal stresses in angle-ply composite laminates  

SciTech Connect

The room temperature stress distributions and shapes of a family of angle ply graphite/epoxy laminates have been obtained using a three-dimensional linear finite element analysis. The sensitivity of the corners to fiber angle variations is examined, in addition to the errors introduced by assuming planes of symmetry which do not exist in angle-ply laminates. The results show that angle ply laminates with clustered plies will tend to delaminate at diagonally opposite corners, and that matrix cracks in this family of laminates will be initiated in the laminate interior. 20 references.

Griffin, O.H. Jr.

1988-01-01

184

Compact low-power high-sensitivity angle sensor  

Microsoft Academic Search

We present the design of a compact battery-powered optical angle sensor, together with the first results obtained using the prototype measuring system. The output of the sensor is proportional to cos 2theta over a full 360°, where theta is the (possibly static) angle of rotation from a designated zero orientation. Over the more limited range of approximately +\\/-20° the measured

N. A. Lockerbie; N. J. McDonald; R. G. Weston

2004-01-01

185

Optimum visual angle for fashion retail window display  

Microsoft Academic Search

This article summarises the findings of a study about the angle from which consumers view displays in fashion stores, as they walk past the store windows. Two experiments were carried out, and the results were used to propose a change in the angle at which window displays are arranged, and where the focus or centre piece of a display should

Z. Li; Thomas Cassidy

2011-01-01

186

Gyroscopic testing of accelerometers to determine coning angle  

Microsoft Academic Search

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

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

1988-01-01

187

Pitch-angle scattering in magnetostatic turbulence. II. Analytical considerations and pitch-angle isotropization  

NASA Astrophysics Data System (ADS)

Aims: The process of pitch-angle isotropization is important for many applications ranging from diffusive shock acceleration to large-scale cosmic-ray transport. Here, the basic analytical description is revisited on the basis of recent simulation results. Methods: Both an analytical and a numerical investigation were undertaken of the Fokker-Planck equation for pitch-angle scattering. Additional test-particle simulations obtained with the help of a Monte-Carlo code were used to verify the conclusions. Results: It is shown that the usual definition of the pitch-angle Fokker-Planck coefficient via the mean-square displacement is flawed. The reason can be traced back to the assumption of homogeneity in time which does not hold for pitch-angle scattering. Conclusions: Calculating the mean free path via the Fokker-Planck coefficient has often proven to give an accurate description. For numerical purposes, accordingly, it is the definition that has to be exchanged in favor of the pitch-angle correlation function.

Tautz, R. C.

2013-10-01

188

Gaze and viewing angle influence visual stabilization of upright posture  

PubMed Central

Focusing gaze on a target helps stabilize upright posture. We investigated how this visual stabilization can be affected by observing a target presented under different gaze and viewing angles. In a series of 10-second trials, participants (N = 20, 29.3 ± 9 years of age) stood on a force plate and fixed their gaze on a figure presented on a screen at a distance of 1 m. The figure changed position (gaze angle: eye level (0°), 25° up or down), vertical body orientation (viewing angle: at eye level but rotated 25° as if leaning toward or away from the participant), or both (gaze and viewing angle: 25° up or down with the rotation equivalent of a natural visual perspective). Amplitude of participants’ sagittal displacement, surface area, and angular position of the center of gravity (COG) were compared. Results showed decreased COG velocity and amplitude for up and down gaze angles. Changes in viewing angles resulted in altered body alignment and increased amplitude of COG displacement. No significant changes in postural stability were observed when both gaze and viewing angles were altered. Results suggest that both the gaze angle and viewing perspective may be essential variables of the visuomotor system modulating postural responses.

Ustinova, KI; Perkins, J

2011-01-01

189

Management of angle closure glaucoma  

PubMed Central

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

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

2011-01-01

190

Linkage studies in primary open angle glaucoma  

SciTech Connect

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

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

1994-09-01

191

Leading Edge Receptivity to Sound at Incidence Angles on Parabolic Bodies at Mean Angles of Attack.  

NASA Astrophysics Data System (ADS)

The leading edge receptivity to acoustic waves of two-dimensional parabolic bodies was investigated using a spatial solution of the Navier-Stokes equations in vorticity/stream function form in parabolic coordinates. The free-stream is composed of a uniform flow with a superposed periodic velocity fluctuation of small amplitude. The method follows that of Haddad & Corke(J. Fluid Mech.), 368, 1998 in which the solution for the basic flow and linearized perturbation flow are solved separately. We primarily investigated the effect of the angle of incidence (-180^circ <= ?1 <= 180^circ) of the acoustic waves on the leading edge receptivity of parabolic bodies at mean angles of attack (0^circ <= ?2 <= 7^circ). The results at ?_1=?_2=0^circ quantitatively agree with those of Haddad & Corke, which showed an increase in the receptivity coefficient with increasing angle of attack. Of special interest is an asymmetry in the receptivity coefficient when determined by extrapolation to the leading from the lower or upper sides of the body, which is produced when the sound incidence angles and angles of attack are large.

Corke, T. C.; Erturk, E.

1999-11-01

192

Progress in phase angle thermography  

Microsoft Academic Search

Phase angle thermography is basically spatially multiplexed photothermal radiometry. It provides images for remote detection and imaging of damage. For energy deposition one can use external heat sources (e.g., light or convective heating) or internal heat generation (e.g., electric current, microwaves, eddy current, or elastic wave). More complete information about defects is obtained by combining information from external and internal

A. Dillenz; T. Zweschper; G. Riegert; G. Busse

2003-01-01

193

Variable angle asymmetric cut monochromator.  

National Technical Information Service (NTIS)

A variable incident angle, asymmetric cut, double crystal monochromator was tested for use on beamlines at the Advanced Photon Source (APS). For both undulator and wiggler beams the monochromator can expand area of footprint of beam on surface of the crys...

R. K. Smither P. B. Fernandez

1993-01-01

194

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

195

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

196

Penetrating facial injury from angle grinder use: management and prevention  

PubMed Central

Injuries resulting from the use of angle grinders are numerous. The most common sites injured are the head and face. The high speed disc of angle grinders does not respect anatomical boundaries or structures and thus the injuries produced can be disfiguring, permanently disabling or even fatal. However, aesthetically pleasing results can be achieved with thorough debridement, resection of wound edges and careful layered functional closure after reduction and fixation of facial bone injuries. A series of penetrating facial wounds associated with angle grinder use are presented and the management and prevention of these injuries discussed.

Carter, Lachlan M; Wales, Craig J; Varley, Iain; Telfer, Martin R

2008-01-01

197

Gaia basic angle monitoring system  

NASA Astrophysics Data System (ADS)

The Gaia mission will create an extraordinarily precise three-dimensional map of more than one billion stars in our Galaxy. The Gaia spacecraft, 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’. This accuracy requires ultra-high stability, 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 system for this mission. The BAM measures 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 measure Optical Path Differences (OPD) as small as 1.5 picometer rms. Following a general introduction to the Gaia mission, the Payload Module (PLM) and the use of Silicon Carbide as base material, this presentation will address an overview of the challenges towards the key requirements, design, integration and testing (including space-level qualification) of the Gaia BAM.

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

2012-09-01

198

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

199

Small angle scattering and asphaltenes  

NASA Astrophysics Data System (ADS)

Petroleum is a mixture of organic material consisting of a series of molecules with increasing molecular weight but with decreasing carbon to hydrogen ratios. This monotonic trend leads to distinctive properties of each class, cut by solvents. Asphaltenes are a class soluble in toluene but not in heptane. The importance of asphaltenes lies in their relevance to petroleum operations. Many properties of petroleum liquids are due to the interplay between asphaltenes and other co-existing components. These complex interactions impact on petroleum phases, and thus the operations. So-called petroleomics is a scheme to link the molecular structures of the most relevant components in the petroleum liquid to its overall properties, similar to the proteomics widely accepted in biological sciences. However, though the asphaltene molecular structure and compositions are relevant to the macroscopic properties of petroleum liquids, their aggregates on the colloidal length scale could be the most relevant elementary unit that dictates the properties of the petroleum mixtures. In this regard, it is legitimate to use small angle x-ray scattering (SAXS) and small angle neutron scattering (SANS) techniques to bridge the molecular structures of asphaltenes and the operational parameters that are commonly applied in the field. In this review, the linkages between asphaltene molecules and their aggregates and the asphaltene aggregates and the macroscopic properties are described. Applications of small angle x-ray and neutron scattering for characterizing asphaltene aggregates and asphaltene emulsions are also discussed.

Sheu, Eric Y.

2006-09-01

200

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

201

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.

Linthorne, Nicholas P.; Patel, Dipesh S.

2011-01-01

202

Angle-closure glaucoma: the role of the lens in the pathogenesis, prevention, and treatment.  

PubMed

Primary angle-closure glaucoma is a major cause of blindness worldwide. It is a disease of ocular anatomy that is related to pupillary-block and angle-crowding mechanisms of filtration angle closure. Eyes at increased risk for primary angle-closure are small with decreased axial length, anterior chamber depth, and filtration angle width, associated with a proportionately large lens. Angle-closure glaucoma afflicts Asian and Eskimo eyes more frequently than eyes in other races with similar predisposing dimensions. The treatment of primary angle closure addresses its causal mechanisms. Laser peripheral iridotomy equalizes the anterior and posterior pressures and widens the filtration angle by reducing the effect of pupillary block. Argon laser peripheral iridoplasty contracts the iris stroma to reduce angle crowding and is helpful for some affected eyes. Lensectomy dramatically widens the angle and eliminates pupillary block. Clinical reports of lensectomy with posterior chamber intraocular lens implantation in the treatment of acute, chronic, and secondary angle-closure glaucoma describe very favorable results. The appropriate role for lensectomy in the management of primary angle closure, however, remains unproven. Prospective, randomized clinical trials are ongoing to determine the value and comparative risks and efficacy of lensectomy versus medical therapy, laser peripheral iridotomy, laser iridoplasty, and filtration procedures for the treatment of acute and chronic primary angle closure and for the prevention of chronic angle-closure glaucoma, both after and in place of laser peripheral iridotomy. PMID:19298900

Tarongoy, Pamela; Ho, Ching Lin; Walton, David S

203

Multilateration with the wide-angle airborne laser ranging system: positioning precision and atmospheric effects.  

PubMed

Numerical simulations based on previously validated models for the wide-angle airborne laser ranging system are used here for assessing the precision in coordinate estimates of ground-based cube-corner retroreflectors (CCR's). It is shown that the precision can be optimized to first order as a function of instrument performance, number of laser shots (LS's), and network size. Laser beam divergence, aircraft altitude, and CCR density are only second-order parameters, provided that the number of echoes per LS is greater than 20. Thus precision in the vertical is approximately 1 mm, with a signal-to-noise ratio of 50 at nadir, a 10-km altitude, a 20 degrees beam divergence, and approximately 5 x 10(3) measurements. Scintillation and fair-weather cumulus clouds usually have negligible influence on the estimates. Laser biases and path delay are compensated for by adjustment of aircraft offsets. The predominant atmospheric effect is with mesoscale nonuniform horizontal temperature gradients, which might lead to biases near 0.5 mm. PMID:18319932

Bock, O

1999-05-20

204

Measurement of critical contact angle in a microgravity space experiment  

SciTech Connect

Mathematical theory predicts that small changes in container shape or in contact angle can give rise to large shifts of liquid in a microgravity environment. This phenomenon was investigated in the Interface Configuration Experiment on board the NASA USML-2 Space Shuttle flight. The experiment's double proboscis containers were designed to strike a balance between conflicting requirements of sizable volume of liquid shift (for ease of observation) and abruptness of the shift (for accurate determination of critical contact angle). The experimental results support the classical concept of macroscopic contact angle and demonstrate the role of hysteresis in impeding orientation toward equilibrium.

Concus, P.; Finn, R.; Weislogel, M.

1999-06-01

205

Angles, Scales and Parametric Renormalization  

NASA Astrophysics Data System (ADS)

We discuss the structure of renormalized Feynman rules. Regarding them as maps from the Hopf algebra of Feynman graphs to {{C}} originating from the evaluation of graphs by Feynman rules, they are elements of a group {G=Spec_{Feyn}(H)} . We study the kinematics of scale and angle-dependence to decompose G into subgroups {G_{{1-s}}} and {G_{fin}} . Using parametric representations of Feynman integrals, renormalizability and the renormalization group underlying the scale dependence of Feynman amplitudes are derived and proven in the context of algebraic geometry.

Brown, Francis; Kreimer, Dirk

2013-09-01

206

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

207

Angle-of-Attack Computation Study.  

National Technical Information Service (NTIS)

The report discusses methods of computing angle of attack by influence using combinations of data from presently available, on-board sensors, thereby eliminating the need for external vanes or probes. Equations were derived from which computed angle of at...

J. B. Dendy K. G. Transier

1969-01-01

208

Single miniplate osteosynthesis in angle fracture  

PubMed Central

Aim: The present study was designed to study the feasibility of single miniplate osteosynthesis in the fracture of angle of mandible. Materials and Methods: in this study 110 patient were included and treated with single miniplate osteosynthesis at upper border along champy's line of osteosynthesis. Results: All the cases were treated successfully, common complications which we have observed in this study, cosmetic disfigurement, delayed union, infection, wound dehiscence and paresthesia. Conclusion: Single miniplate fixation in unfavorable fracture is questionable and hence these fracture require some alternative method (locking plate, etc.) for fixation.

Singh, R. K.; Pal, U. S.; Agrawal, Amiya; Singh, Geeta

2011-01-01

209

A spin- and angle-resolving photoelectron spectrometer  

SciTech Connect

A new type of hemispherical electron energy analyzer that permits angle and spin resolved photoelectron spectroscopy has been developed. The analyzer permits standard angle resolved spectra to be recorded with a two-dimensional detector in parallel with spin detection using a mini-Mott polarimeter. General design considerations as well as technical solutions are discussed and test results from the Au(111) surface state are presented.

Berntsen, M. H.; Tjernberg, O. [Materials Physics, KTH Royal Institute of Technology, S-16440 Kista (Sweden); Palmgren, P.; Leandersson, M. [MAX-lab, P.O. Box 118, S-22100 Lund (Sweden); Hahlin, A.; Aahlund, J. [VG Scienta AB, P.O. Box 12120, SE-75015 Uppsala (Sweden); Wannberg, B. [VG Scienta AB, P.O. Box 12120, SE-75015 Uppsala (Sweden); BW Particle Optics AB, P.O. Box 55, SE-82222 Alfta (Sweden); Maansson, M. [Laboratory for Neutron Scattering, ETH Zurich (Switzerland) and Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland) and Laboratory for Synchrotron and Neutron Spectroscopy, EPFL, CH-1015 Lausanne (Switzerland)

2010-03-15

210

Experimental demonstration of body slip angle control based on a novel linear observer for electric vehicle  

Microsoft Academic Search

In this paper, a body slip angle observer based on yaw rate ? and side acceleration ay, and a novel control method of body slip angle ? are proposed. Body slip angle observer is robust against parameter variation and change of road. Some experimental results by UOT MarchII (Fig.1) are shown to verify the effectiveness of the proposed observer. Next,

Yoshifumi Aoki; Toshiyuki Uchida; Yoichi Hori

2005-01-01

211

Large-scale molecular dynamics simulations of glancing angle deposition  

NASA Astrophysics Data System (ADS)

Using a computationally efficient method, we have carried out large-scale molecular dynamics simulations of Cu/Cu(100) growth up to 20 monolayers (ML) for deposition angles ranging from 50° to 85° and for both random and fixed azimuthal angles. A variety of quantities including the porosity, roughness, lateral correlation length, average grain size, strain, and defect concentration are used to characterize the thin-film morphology. For large deposition angles (?>=80°), we find well-defined columnar growth while for smaller angles, columnar growth has not yet set in. In addition, for ?=70°-85°, the thin-film porosity and columnar tilt angles (for fixed azimuthal angle ?) are in reasonable agreement with experiments. For both random and fixed ?, the number of grains, average grain-size, and number of surface atoms belonging to (111) facets increase rapidly with deposition angle. As a result, twin facet formation and budding occur in our simulations, in good agreement with experiments. In good qualitative agreement with recent experimental observations, we also find that the average strain is initially compressive but becomes tensile after the onset of columnar growth. Our simulations also reveal that for large deposition angles a variety of unexpected and complex dynamical processes play a key role in determining the evolution of the surface morphology and microstructure. In particular, due to the existence of deposition-induced events, the vacancy density remains very small, even though the defect density is relatively large and increases with deposition angle. In addition, large-scale re-arrangement events as well as thermal (elastic) vibrations lead to large-amplitude oscillations in the columnar growth regime. These oscillations play a key role in promoting rapid coalescence via additional large-scale collective motion, thus, significantly enhancing the coarsening process.

Hubartt, Bradley C.; Liu, Xuejing; Amar, Jacques G.

2013-08-01

212

Measurement of Strabismic Angle Using the Distance Krimsky Test  

PubMed Central

Purpose To evaluate the correlation of the distance Krimsky test and the alternate prism cover test (APCT) for the distance deviation in patients with horizontal strabismus. Methods Forty patients with horizontal strabismus (20 esotropia and 20 exotropia) were included in this study. Patients with a variable angle of deviation, vertical angle over 5 prism diopters, impaired binocular vision, or poor cooperation were excluded. We instructed the patient to look a target 6 meters away, and applied a prism over the patient's dominant eye while flashing a light source 33 centimeters from the middle of both eyebrows. When the corneal light reflexes were located on the center of each cornea, we measured the angle of deviation. We defined this method as 'distance Krimsky test,' and the angle measured by this method was compared with the conventional Krimsky test and APCT at distance. We analyzed the accuracy and intra- and inter-observer reliability. Results The angle of strabismus measured by the distance Krimsky test showed a significant agreement and correlation with the deviation angle measured by the APCT. We elicited the correlation gradient between the angle measured by the distance Krimsky test and the APCT. In addition, the distance Krimsky test showed significant intra- and inter-observer reliabilities. Conclusions The distance Krimsky test is expected to be more useful than the Krimsky test in measuring the distance angle of deviation for patients with strabismus in whom it is difficult to measure the angle of deviation using the APCT. The distance Krimsky test can be an accurate and useful test through the improvement of proficiency of examiners and the establishment of individualized normative data.

Joo, Kwang Sic; Koo, Hyun

2013-01-01

213

FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Temperature Influence on Divergence Angles of Quartz Crystal Wollaston Prism  

NASA Astrophysics Data System (ADS)

We propose a structural angle and main refractive indices as two key factors to understand the temperature influence on the divergence angles of the Wollaston prism. The temperature influence on the divergence angles of quartz crystal Wollaston prism is studied theoretically The results show that divergence angles decrease with increasing temperature, while the divergence angle of e-light decrease more quickly than that of o-light. The testing system is established to verify the above results, and the experimental results are in agreement well with the theoretical analysis.

Zhao, Shuang; Wu, Fu-Quan; Zhang, Dong-Sheng; Zhao, Xin; Wang, Jin-Xi; Xue, Mei; Zhong, Wei-Gang

2008-07-01

214

Installation Design of Solar Panels with Seasonal Adjustment of Tilt-Angles  

Microsoft Academic Search

In this work, a mathematical procedure was developed for estimating the annual collectible radiation on solar panels with different mode of tilt-angle adjustment based on the monthly horizontal radiation. Calculation results show that, for solar panels with seasonal adjustment of tilt-angles, the optimum date of tilt-angle adjustment is 22 days from the equinoxes, and the optimum value of tilt-angle adjustment

Runsheng Tang; Xinyue Liu

2010-01-01

215

Effects of swirling airflow and divergence angle of airblast atomizer on atomization performance  

NASA Astrophysics Data System (ADS)

The effects of swirling airflow and divergence angle on the atomizing performance of an airblast atomizer were studied. Six different atomizers having three kinds of blade angle swirlers and three kinds of exit divergence angle have been tested, and the results have been analyzed. It is concluded that the swirling airflow and the divergence angle have little influence on the atomizing performance. Therefore atomizers may be designed chiefly according to the flow pattern needed in the combustor.

Zhao, Qishou; Lin, Lijun; Yuan, Quanchao

1987-04-01

216

The posterior condylar angle in osteoarthritic knees  

Microsoft Academic Search

The posterior condylar angle is formed by the transepicondylar axis and the tangent line to the posterior condyles. It is an important relationship to determine rotational alignment of the femoral component in total knee arthroplasty. We measured this angle directly in 107 osteoarthritic knees undergoing total knee arthroplasty. The posterior condylar angle was significantly greater in valgus knees than in

Frankie M. Griffin; John N. Insall; Giles R. Scuderi

1998-01-01

217

Dynamic contact angles in CFD simulations  

Microsoft Academic Search

The accurate modelling of contact angle properties plays an important role in the simulation of free-surface micro flows. Taking capillary filling as an example, we first discuss the analytical solutions of a corresponding 1D description in certain limits and then derive an approximate analytical expression for the general case with constant contact angle. In case of a dynamic contact angle

Friedhelm Schönfeld; Steffen Hardt

2009-01-01

218

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

219

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.

220

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

221

Folded cavity angled-grating broad-area lasers.  

PubMed

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

Zhao, Yunsong; Zhu, Lin

2013-10-01

222

Review of cerebellopontine angle medulloblastoma.  

PubMed

Cerebellopontine angle (CPA) medulloblastomas (MB) are rare lesions with few cases previously described in the literature. We report two further cases of CPA MB. The patients were a 22-year-old man and a 26-year-old woman with a mass developing in the CPA. The preoperative radiological diagnosis was vestibular schwannoma in the first case and petrosal meningioma in the second case. The patients were operated on through a retrosigmoid approach. The intraoperative findings revealed an intra-axial tumour and the histological diagnosis was classic type of MB in both cases. We review the literature and discuss pathological and radiological features and possible pathogenesis of CPA MB, underlining the necessity to consider MB in the differential diagnosis of CPA lesions. PMID:23163297

Spina, A; Boari, N; Gagliardi, F; Franzin, A; Terreni, M R; Mortini, P

2012-11-19

223

Comparison of different passive knee extension torque-angle assessments.  

PubMed

Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m(-2); tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome. PMID:24149660

Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro

2013-10-22

224

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

225

Delayed Topiramate-induced Bilateral Angle-Closure Glaucoma.  

PubMed

PURPOSE:: To report a unique case of delayed topiramate-induced bilateral angle closure. METHODS:: A case report of a 40-year-old woman who experienced bilateral acute angle-closure glaucoma and induced myopia on a standard and consistent dose of topiramate for 262 days before the onset of symptoms. Initial and follow-up examination findings were reviewed. RESULTS:: Initial examination revealed finger counting at one foot OU, intraocular pressures of 38 mm Hg OD and 37 mm Hg OS, and bilaterally closed angles with no view of anterior trabecular meshwork (Shaffer grade 0). Discontinuation of topiramate and administration of topical drops were able to break the attack. At 3 months of follow-up, the patient was 20/25 OU with deep angles open to the scleral spur (Shaffer grade III) and had intraocular pressures of 14 mm Hg in both the eyes. CONCLUSIONS:: This case provides evidence of delayed bilateral angle closure from topiramate and raises questions as to the cellular mechanism of topiramate-induced angle closure, both immediate and delayed. PMID:23632405

Czyz, Craig N; Clark, Cooper M; Justice, Joshua D; Pokabla, Michael J; Weber, Paul A

2013-04-29

226

Surface EMG force modeling with joint angle based calibration.  

PubMed

In this paper, a calibration method to compensate for changes in SEMG amplitude with joint angle is introduced. Calibration factors were derived from constant amplitude surface electromyogram (SEMG) recordings from the biceps brachii (during elbow flexion) and the triceps brachii (during elbow extension) across seven elbow joint angles. SEMG data were then recorded from the elbow flexors (biceps brachii and brachioradialis) and extensors (triceps brachii) during isometric, constant force flexion and extension contractions at the same joint angles. The resulting force at the wrist was measured. The fast orthogonal search method was used to find a mapping between the system inputs - estimated SEMG amplitudes and joint angle - and the system output - measured force, for both calibrated and non-calibrated SEMG data. Models developed with calibrated data yielded a statistically significant improvement in force estimation compared to models developed with non-calibrated data, suggesting that the calibration method can compensate for changes in the SEMG-force relationship with changing joint angle. It was also found that the number of non-linear, joint angle-dependent terms used in the SEMG-force model was reduced with calibration. Additionally, initial inter-session analysis performed for four subjects suggests that calibration values can be used for subsequent recording sessions, and different output force levels. PMID:23273763

Hashemi, Javad; Morin, Evelyn; Mousavi, Parvin; Hashtrudi-Zaad, Keyvan

2012-12-25

227

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

228

Contact angle and local wetting at contact line.  

PubMed

This theoretical study was motivated by recent experiments and theoretical work that had suggested the dependence of the static contact angle on the local wetting at the triple-phase contact line. We revisit this topic because the static contact angle as a local wetting parameter is still not widely understood and clearly known. To further clarify the relationship of the static contact angle with wetting, two approaches are applied to derive a general equation for the static contact angle of a droplet on a composite surface composed of heterogeneous components. A global approach based on the free surface energy of a thermodynamic system containing the droplet and solid surface shows the static contact angle as a function of local surface chemistry and local wetting state at the contact line. A local approach, in which only local forces acting on the contact line are considered, results in the same equation. The fact that the local approach agrees with the global approach further demonstrates the static contact angle as a local wetting parameter. Additionally, the study also suggests that the wetting described by the Wenzel and Cassie equations is also the local wetting of the contact line rather than the global wetting of the droplet. PMID:23066985

Li, Ri; Shan, Yanguang

2012-10-24

229

Reexamination of fault angles predicted by shear localization theory  

SciTech Connect

This paper reexamines orientations of shear bands (fault angles) predicted by a theory of shear localization as a bifurcation from homogeneous deformation. In contrast to the Coulomb prediction, which does not depend on deviatoric stress state, the angle between the band normal and the least (most compressive) principal stress increases as the deviatoric stress state varies from axisymmetric compression to axisymmetric extension. This variation is consistent with the data of Mogi (1967) on Dunham dolomite for axisymmetric compression, extension and biaxial compression, but the predicted angles are generally less than observed. This discrepancy may be due to anisotropy that develops due to crack growth in preferred orientations. Results from specialized constitutive relations for axisymmetric compression and plane strain that include this anisotropy indicate that it tends to increase the predicted angles. Measurements for a weak, porous sandstone (Castlegate) indicate that the band angle decreases with increasing inelastic compaction that accompanies increasing mean stress. This trend is consistent with the predictions of the theory but, for this rock, the observed angles are less than predicted.

Rudnicki, J.W. [Northwestern Univ., Evanston, IL (United States). Dept. of Civil Engineering; Olsson, W.A. [Sandia National Labs., Albuquerque, NM (United States). Geomechanics Dept.

1998-02-01

230

Bending analysis of angle-ply laminates  

NASA Astrophysics Data System (ADS)

The accuracy and the applicability of the higher-order theory developed by Savithri and Varadan (1990) for the analysis of symmetric angle-ply laminates were assessed by comparing results obtained with this theory, which incorporates the continuity of transverse shear stresses at the interfaces, with results obtained with the smeared laminate theory of Reddy (1984). For this comparison a laminate plate is used which is composed of a finite number of anisotropic layers, each of which has only a single plane of elastic symmetry parallel to the XY plane; the plate is assumed to be simply supported on the boundaries and subjected to normal traction (q(X,Y)) on the upper surface. It was found that the new theory is highly accurate for symmetric laminates, and, for comparable accuracies, the computation cost is much less than that of the corresponding smeared laminate theory.

Savithri, S.; Varadan, T. K.

1991-05-01

231

Dosimetric comparison of manual and beam angle optimization of gantry angles in IMRT.  

PubMed

Dosimetric comparison of manual beam angle selection (MBS) and beam angle optimization (BAO) for IMRT plans is investigated retrospectively for 15 head and neck and prostate patients. The head and neck and prostate had planning target volumes (PTVs) ranging between 96.0 and 319.9 cm(3) and 153.6 and 321.3 cm(3), whereas OAR ranged between 8.3 and 47.8 cm(3) and 68.3 and 469.2 cm(3), respectively. In MBS, a standard coplanar 7-9 fields equally spaced gantry angles were used. In BAO, the selection of gantry angle was optimized by the algorithm for the same number of beams. The optimization and dose-volume constraints were kept the same for both techniques. Treatment planning was performed on the Eclipse treatment planning system. Our results showed that the dose-volume histogram for PTV are nearly identical in both techniques but BAO provided superior sparing of the organs at risk compared with the MBS. Also, MBS produced statistically significant higher monitor units (MU) and segments than the BAO; 13.1 ± 6.6% (p = 0.012) and 10.4 ± 13.6% (p = 0.140), and 14.6 ± 5.6% (p = 1.003E-5) and 12.6 ± 7.4% (p = 0.76E-3) for head and neck and prostate cases, respectively. The reduction in MU translates into the reduction in total body and integral dose. It is concluded that BAO provides advantage over MBS for most intenisty-modulated radiation therapy cases. PMID:20817436

Srivastava, Shiv P; Das, Indra J; Kumar, Arvind; Johnstone, Peter A S

2010-09-03

232

[Reduction gonioplasty for the prominent mandibular angle. Report of 38 cases].  

PubMed

The one-stage curved osteotomy of the mandibular angle without resection of the masseter was used for 38 patients suffering from prominent mandibular angle from december 1996 to november 1997 at our department of plastic and cranio-maxillo-facial surgery. The preoperative strategy and surgical procedure are described. These 38 cases had a low rate of complications and usually good cosmetic results. Technical refinements that have improved the results are analyzed. At the present time the one-stage curved osteotomy of the mandibular angle is a simple and more reliable method for the surgical correction of the prominent mandibular angle, which is preferred by us to the other techniques: resection of the masseter alone or with straight cutting of the mandibular angle, simple straight cutting of the mandibular angle, multistaged osteotomy of the mandibular angle. PMID:11534448

Gui, L; Athmani, B; Zhang, Z Y; Ten, L

2001-08-01

233

Submillimetre polarimetric observations of S140 and GL 2591: investigating the role of viewing angle on observed polarization position angles.  

NASA Astrophysics Data System (ADS)

We have measured the 800?m polarization at three positions towards S140 and at the flux peak towards GL 2591. For both sources the implied magnetic field direction is neither parallel nor perpendicular to the outflow axis, implying an "in-between" situation. A review of published submillimetre polarimetric observations of outflow sources implies this scenario is common. Whilst beamsize effects are not thought to be critical, comparison of these observations with the results from a recent theoretical model (Bonifacio & Emerson 1995, ASP Conf. Ser., 97, 363) imply that the "in-between" situations may actually be due to the effect of viewing angle on the observed polarization position angle. If the local magnetic field is uniform and perpendicular to the outflow axis the observed position angle of polarization for dichroic emission of aligned grains is highly dependent on the viewing angle. The surprising agreement between mid-infrared and submillimetre emissive polarization position angles for W3-IRS5, NGC 7538-IRS1 and OMC1-IRc2, and their non-orthogonality to the mid-IR absorptive polarization position angles, has implications for the magnetic field configuration around these outflow sources. In particular, an hour-glass magnetic field geometry may be applicable.

Minchin, N. R.; Bonifacio, V. H. R.; Murray, A. G.

1996-11-01

234

Angiomas of the cerebellopontine angle.  

PubMed

Angiomas situated within the pontocerebellar cistern lie superficially on the ventrolateral aspect of the brain stem. Occasionally, minor extensions penetrate into the adjacent nervous structures. Five patients bearing such lesions were operated upon, using a microsurgical technique. Radical excision was performed in all cases. Within 2 to 12 months the patients had returned to their previous occupations, being fully able to work or attend school. There is increasing evidence for the effectiveness of surgical treatment of angiomas of the ventrolateral aspect of the brain stem and the cerebellopontine angle. The illness usually presents with hemorrhages of varying severity, ranging from mild to devastating. Impairment of consciousness, contralateral hemiparesis and ipsilateral cranial nerve palsies are the most frequent neurological signs after bleeding. The outcome following excision is primarily related to the preoperative condition. No additional deficits or only minor further impairment can be expected from surgical interference. Exploration is advisable whenever the malformation appears to lie on the surface rather than within the brain stem. PMID:6169805

Viale, G L; Pau, A; Viale, E S; Turtas, S

1981-01-01

235

[Screening in open angle glaucoma].  

PubMed

Primary open angle glaucoma (POAG) represents the second cause of mondial cecity, after retinal diabetes complications, with extremely severe implications in quality of life. Screening testing for glaucoma is justified, because only the diagnosis in very incipient stage will preserve the visual function; any treatment will not assure the reversibility of pre-existent optic nerve lesions. Screening of glaucoma, will take into a consideration the costs, the time of investigation, the adverse effects, and the sensitivity and specificity of tests; the last parameter also will strongly influence the positive predictive value. An ideal screening identifies all subjects that present the disease (sensitivity) and will exclude all healthy subjects (specificity). In this moment, in Dolj district, the diagnosis is based on active diagnosis of new cases of glaucoma on the high risk level population, therefore in a 210000 habitants. 4723 patients with glaucoma are diagnosed, screened and follow-up on medical cabinets and on Center of Glaucoma, which coordinates their activity. To better monitored patients, automatized programs with acquisition and storage for different types of medical imaging facilities had become indispensable to any routine practice. PMID:23755511

Mocanu, Carmen; Mocanu, Andrei

2012-01-01

236

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

2010-11-02

237

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

2011-04-21

238

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...

239

Viewing angle control mode using nematic bistability.  

PubMed

As an approach using bistable nematic liquid crystals, we present a liquid crystal display with viewing angle control using two stable states, splay and 180 degrees-twist at pi cell, with three terminal electrode structures. The splay state is controlled by in-plane switching for a wide viewing angle (WVA), while the 180 degrees-twist state is operated by vertical switching for a narrow viewing angle (NVA). With this bistable mode, we fabricated viewing angle-controlled LCDs without additional optical components. PMID:18542350

Gwag, Jin Seog; Lee, You-Jin; Kim, Myung-Eun; Kim, Jae-Hoon; Kim, Jae Chang; Yoon, Tae-Hoon

2008-02-18

240

Thermodynamic modeling of contact angles on rough, heterogeneous surfaces.  

PubMed

Theoretical modelling for contact angle hysteresis carried out to date has been mostly limited to several idealized surface configurations, either rough or heterogeneous surfaces. This paper presents a preliminary study on the thermodynamics of contact angles on rough and heterogeneous surfaces by employing the principle of minimum free energy and the concept of liquid front. Based on a two-dimensional regular model surface, a set of relations were obtained, which correlate advancing, receding and system equilibrium contact angles to surface topography, roughness and heterogeneity. It was found that system equilibrium contact angles (theta(ES)) can be expressed as a function of surface roughness factor (delta) and the Cassie contact angle (theta(C)): costheta(ES) = deltacostheta(C). This expression can be reduced to the classical Wenzel equation.: theta(ES) = theta(W) for rough but homogeneous surfaces, and the classical Cassie equation theta(ES) = theta(C) for heterogeneous but smooth surfaces. A non-dimensional parameter called surface feature factor (omega) was proposed to classify surfaces into three categories (types): roughness-dominated, heterogeneity-dominated and mixed-rough-heterogeneous. The prediction of advancing and receding contact angles of a surface is dependent on which category the surface belongs to. The thermodynamic analysis of contact angle hysteresis was further extended from the regular model surface to irregular surfaces; consistent results were obtained. The current model not only agrees well with the models previously studied by other researchers for idealized surfaces, but also explores more possibilities to explain the reported experimental results/observations that most existing theories could not explain. PMID:16154106

Long, J; Hyder, M N; Huang, R Y M; Chen, P

2005-09-09

241

Distinguishing features of shallow angle plunging jets  

NASA Astrophysics Data System (ADS)

Numerical simulations employing an algebraic volume-of-fluid methodology are used to study the air entrainment characteristics of a water jet plunging into a quiescent water pool at angles ranging from ? = 10° to ? = 90° measured from the horizontal. Our previous study of shallow angled jets [S. S. Deshpande, M. F. Trujillo, X. Wu, and G. L. Chahine, ``Computational and experimental characterization of a liquid jet plunging into a quiescent pool at shallow inclination,'' Int. J. Heat Fluid Flow 34, 1-14 (2012)] revealed the existence of a clearly discernible frequency of ingestion of large air cavities. This is in contrast with chaotic entrainment of small air pockets reported in the literature in case of steeper or vertically plunging jets. In the present work, the differences are addressed by first quantifying the cavity size and entrained air volumes for different impingement angles. The results support the expected trend - reduction in cavity size (D43) as ? is increased. Time histories of cavity volumes in the vicinity of the impingement region confirm the visual observations pertaining to a near-periodic ingestion of large air volumes for shallow jets (10°, 12°), and also show that such cavities are not formed for steep or vertical jets. Each large cavity (defined as Dc/Dj >~ 3) exists in close association with a stagnation point flow. A local mass and momentum balance shows that the high stagnation pressure causes a radial redirection of the jet, resulting in a flow that resembles the initial impact of a jet on the pool. In fact, for these large cavities, their speed matches closely Uimpact/2, which coincides with initial cavity propagation for sufficiently high Froude numbers. Furthermore, it is shown that the approximate periodicity of air entrainment scales linearly with Froude number. This finding is confirmed by a number of simulations at ? = 12°. Qualitatively, for steeper jets, such large stagnation pressure region does not exist, and the deflection of the entire incoming jet is non-existent. In fact, for ? = 25°, 45°, 90°, the jet penetrates the pool nearly undisturbed and consequently large cavities are not formed.

Deshpande, Suraj S.; Trujillo, Mario F.

2013-08-01

242

A superconducting large-angle magnetic suspension  

NASA Astrophysics Data System (ADS)

SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demonstration of the control technology required to develop an advanced momentum exchange effector. The Phase 2 research was directed toward the demonstration for the key technology required for the advanced concept CMG, the controller. The Phase 2 hardware consists of a superconducting solenoid ('source coils') suspended within an array of nonsuperconducting coils ('control coils'), a five-degree-of-freedom positioning sensing system, switching power amplifiers, and a digital control system. The results demonstrated the feasibility of suspending the source coil. Gimballing (pointing the axis of the source coil) was demonstrated over a limited range. With further development of the rotation sensing system, enhanced angular freedom should be possible.

Downer, James R.; Anastas, George V., Jr.; Bushko, Dariusz A.; Flynn, Frederick J.; Goldie, James H.; Gondhalekar, Vijay; Hawkey, Timothy J.; Hockney, Richard L.; Torti, Richard P.

1992-12-01

243

Measurements of the KM Angle at ?| at Belle  

NASA Astrophysics Data System (ADS)

Results from the Belle experiment related to the KM angle ?1 are reported. These results include sin2?1 measurements using decays of neutral B meson via the b -> cbar {c}s, b -> cbar {c}d and b -> sqbar {q} processes.

Hastings, Nicholas C.

2005-04-01

244

Ozone column and solar zenith angle effects on ozone photolysis  

NASA Astrophysics Data System (ADS)

The photodissociation of ozone is a primary source of highly reactive hydroxyl radicals that drive daytime atmospheric chemistry. Thus, understanding the radiative processes that effect measurement and modeling of ozone photolysis is critically important to photochemistry. This study examines a counterintuitive relationship between ozone photolysis and variations in total ozone column and solar zenith angle. Results from the National Center for Atmospheric Research (NCAR) Tropospheric Ultraviolet and Visible (TUV) clear sky radiation model indicate that a higher ozone column has a diminishing relative effect on the ozone photolysis for solar zenith angles increasing beyond approximately 65 degrees. This is attributable to the increase in the ozone airmass at high solar zenith angles that results in a decrease in UV-B photons and shifts the ozone photolysis action spectra to higher wavelengths. The effects of modeling variations in altitude, albedo, aerosol attributes and ozone columns are examined and compared with measured data from the NCAR CCD actinic flux spectroradiometers (CAFS).

Hall, S. R.; Ullmann, K.; Madronich, S.; Anderson, B. E.; Hair, J. W.

2010-12-01

245

Structure Inclination Angles in the Convective Atmospheric Surface Layer  

NASA Astrophysics Data System (ADS)

Two-point correlations of the fluctuating streamwise velocity are examined in the atmospheric surface layer over the salt flats of Utah's western desert, and corresponding structure inclination angles are obtained for neutral, stable and unstable conditions. The neutral surface-layer results supplement evidence for the invariance of the inclination angle given in Marusic and Heuer (Phys Rev Lett 99:114504, 2007). In an extension of those results it is found that the inclination angle changes drastically under different stability conditions in the surface layer, varying systematically with the Monin-Obukhov stability parameter in the unstable regime. The variation is parametrized and subsequently can be used to improve existing near-wall models in the large-eddy simulation of the atmospheric surface layer.

Chauhan, Kapil; Hutchins, Nicholas; Monty, Jason; Marusic, Ivan

2013-04-01

246

Structure Inclination Angles in the Convective Atmospheric Surface Layer  

NASA Astrophysics Data System (ADS)

Two-point correlations of the fluctuating streamwise velocity are examined in the atmospheric surface layer over the salt flats of Utah's western desert, and corresponding structure inclination angles are obtained for neutral, stable and unstable conditions. The neutral surface-layer results supplement evidence for the invariance of the inclination angle given in Marusic and Heuer (Phys Rev Lett 99:114504, 2007). In an extension of those results it is found that the inclination angle changes drastically under different stability conditions in the surface layer, varying systematically with the Monin-Obukhov stability parameter in the unstable regime. The variation is parametrized and subsequently can be used to improve existing near-wall models in the large-eddy simulation of the atmospheric surface layer.

Chauhan, Kapil; Hutchins, Nicholas; Monty, Jason; Marusic, Ivan

2012-11-01

247

Assessment of angle velocity in girls with adolescent idiopathic scoliosis  

PubMed Central

Background Although it has been demonstrated that the peak height velocity (PHV) is a predictive factor of progression in adolescent idiopathic scoliosis (AIS), little is known about the usefulness of angle progression in clinical practice. The purpose of this study was to establish a relationship between height and angle velocities, as well as to determine if peak angle velocity (PAV) occurs at the same time than PHV. Methods A retrospective study of a cohort of girls with idiopathic scoliotic curves greater than 10°. Data of 132 girls who participated in a previous retrospective study about growth in AIS were used to calculate height and angle velocities. Relationship between height and angle velocities was estimated by the use of a Linear Mixed Model. Results PHV and PAV take place simultaneously 1 year before menarche in progressive curves managed with a brace in AIS. Changes in angle velocity are influenced by changes in height growth velocity, in such a way that as from 6 months post-menarche, height growth velocity in this group of girls estimates curve progression velocity (?-coefficient -0.88, p = 0.04). Conclusion As from 6 months post-menarche, there is an inverse relationship between height velocity and curve progression in the group of AIS girls with progressive curves managed with a brace. Because height velocity is decreasing from 1 year before menarche, this finding corroborates that at the end of puberty, there is still a risk of progression in this group of girls despite bracing. The assessment of both height and angle velocity might be useful in clinical practice at the time of assessing brace effectiveness and how long bracing has to be indicated.

Escalada, Ferran; Marco, Ester; Duarte, Esther; Ma Muniesa, Josep; Boza, Roser; Tejero, Marta; Caceres, Enric

2009-01-01

248

Optimum release angle in the shot put  

Microsoft Academic Search

The aim of the study was to assess the accuracy of a method of calculating the optimum release angle in the shot put. Using the proposed method, the optimum release angle that produces the greatest flight distance is calculated by combining the equation for the range of a projectile in free flight with the relations between release speed, release height

Nicholas P. Linthorne

2001-01-01

249

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

250

High Angle Conveyor Study. Volume II.  

National Technical Information Service (NTIS)

The study examines the use of a high angle conveying system in an open pit mine. It identifies available high angle conveying equipment and examines the haulage and crushing costs associated with both a conventional truck and shovel mining operation and a...

E. A. Mevissen A. C. Siminerio J. A. Dos Santos

1981-01-01

251

Updated Results of Magnetic Resonance Imaging Guided Partial Prostate Brachytherapy for Favorable Risk Prostate Cancer: Implications for Focal Therapy  

PubMed Central

Purpose We report updated results of magnetic resonance imaging guided partial prostate brachytherapy and propose a definition of biochemical failure following focal therapy. Materials and Methods From 1997 to 2007, 318 men with cT1c, prostate specific antigen less than 15 ng/ml, Gleason 3 + 4 or less prostate cancer received magnetic resonance imaging guided brachytherapy in which only the peripheral zone was targeted. To exclude benign prostate specific antigen increases due to prostatic hyperplasia, we investigated the usefulness of defining prostate specific antigen failure as nadir +2 with prostate specific antigen velocity greater than 0.75 ng/ml per year. Cox regression was used to determine the factors associated with prostate specific antigen failure. Results Median followup was 5.1 years (maximum 12.1). While 36 patients met the nadir +2 criteria, 16 of 17 biopsy proven local recurrences were among the 26 men who also had a prostate specific antigen velocity greater than 0.75 ng/ml per year (16 of 26 vs 1 of 10, p = 0.008). Using the nadir +2 definition, prostate specific antigen failure-free survival for low risk cases at 5 and 8 years was 95.1% (91.0–97.3) and 80.4% (70.7–87.1), respectively. This rate improved to 95.6% (91.6–97.7) and 90.0% (82.6–94.3) using nadir +2 with prostate specific antigen velocity greater than 0.75 ng/ml per year. For intermediate risk cases survival was 73.0% (55.0–84.8) at 5 years and 66.4% (44.8–81.1) at 8 years (the same values as using nadir +2 with prostate specific antigen velocity greater than 0.75 ng/ml per year). Conclusions Requiring a prostate specific antigen velocity greater than 0.75 ng/ml per year in addition to nadir +2 appears to better predict clinical failure after therapies that target less than the whole gland. Further followup will determine whether magnetic resonance imaging guided brachytherapy targeting the peripheral zone produces comparable cancer control to whole gland treatment in men with low risk disease. However, at this time it does not appear adequate for men with even favorable intermediate risk disease.

Nguyen, Paul L.; Chen, Ming-Hui; Zhang, Yuanye; Tempany, Clare M.; Cormack, Robert A.; Beard, Clair J.; Hurwitz, Mark D.; Suh, W. Warren; D'Amico, Anthony V.

2013-01-01

252

GR Schwarzschild Light Launch Angle Program  

NSDL National Science Digital Library

The GR Schwarzschild Light Launch Angle program simulates the path of light around a black hole using the Schwarzschild metric and allows the user to set the launch angle of the light. It also displays a plot of the effective potential well for the light. The default setting is light with an r-coordinate value of 3.5 and a launch angle of 1.571 (in radians). GR Schwarzschild Light Launch Angle Parameter is part of a suite of Open Source Physics programs that model aspects of General Relativity. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the gr_schwarzschild_light_launch_angle.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or General Relativity.

Christian, Wolfgang; Belloni, Mario; Cox, Anne

2008-05-27

253

[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

254

Dynamic-angle spinning of quadrupolar nuclei  

NASA Astrophysics Data System (ADS)

In dynamic-angle spinning (DAS), a sample spins around an axis inclined at an angle ?(t) with respect to the magnetic field such that the averages of Pn(cos?) are zero. The simplest case is where ?(t) assumes two discrete values ?1 and ?2 (complementary DAS angles) such that the averages of P2(cos?) and P4(cos?) are zero, thereby removing second-order quadrupolar (and dipolar) broadening. Examples of DAS complementary angles are ?1=37.38° and ?2=79.18°. Experimental details for DAS experiments are provided and applications to sodium-23 and oxygen-17 NMR illustrate the enhanced resolution achieved by removing the second-order broadening inherent in magic-angle spinning.

Mueller, K. T.; Sun, B. Q.; Chingas, G. C.; Zwanziger, J. W.; Terao, T.; Pines, A.

2011-12-01

255

Development of Tibiofemoral Angle in Korean Children  

PubMed Central

This study was performed to identify the chronological changes of the knee angle or the tibiofemoral angles in normal healthy Korean children. Full-length anteroposterior view standing radiographs of 818 limbs of 452 Korean children were analyzed. The overall patterns of the chronological changes in the knee angle were similar to those described previously in western or Asian children, but the knee angle development was delayed, i.e., genu varum before 1 yr, neutral at 1.5 yr, increasing genu valgum with maximum a value of 7.8° at 4 yr, followed by a gradual decrease to approximately 5-6° of genu valgum of the adult level at 7 to 8 yr of age. These normative data on chronological changes of knee angles should be taken into consideration when evaluating lower limb alignment in children.

Yoo, Jae Ho; Cho, Tae-Joon; Chung, Chin Youb; Yoo, Won Joon

2008-01-01

256

Saturation and the zenith angle dependence of atmospheric isoplanatic angle measurements  

NASA Astrophysics Data System (ADS)

A 10-11 cm aperture stellar scintillometer can measure atmospheric isoplanatic angles reliably provided the normalized variance and the zenith angle of the data are sufficiently, restricted. Within these constraints, the normalized variance data has a zenith angle power law that is quite close to the theoretical prediction. This is a self-consistent indication that the instrument is actually measuring the isoplanatic angle.

Walters, D. L.

257

Non-Contact Ultrasonic Characterization of Angled Surface Defects  

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

258

Planar covariation of elevation angles in prosthetic gait.  

PubMed

In order to achieve efficacious walking, transfemoral amputees must adapt coordination within both the artificial and the sound lower limb. We analyzed kinematic strategies in amputees using the planar covariation of lower limb segments approach. When the elevation angles of the thigh, shank and foot are plotted one versus the others, they describe a regular loop which lies close to a plane in normal adults' gait. Orientation of this plane changes with increased speed, in relation to mechanical energetic saving. We used an opto-electronic device to record the elevation angles of both limbs' segments of novice and expert transfemoral amputees and compared them to those of control subjects. The statistical structure underlying the distribution of these angles was described by principal component analysis and Fourier transform. The typical elliptic loop was preserved in prosthetic walking, in both limbs in both novice and expert transfemoral amputees. This reflects a specific control over the thigh elevation angle taking into account knowledge of the other elevation angles throughout the gait cycle. The best-fitting plane of faster trials rotates around the long axis of the gait loop with respect to the plane of slower trials for control subjects, and even more for the sound limb of expert amputees. In contrast, plane rotation is very weak or absent for the prosthetic limb. We suggest that these results reveal a centrally commanded compensation strategy. PMID:22257927

Leurs, F; Bengoetxea, A; Cebolla, A M; De Saedeleer, C; Dan, B; Cheron, G

2012-01-17

259

A fringe shadow method for measuring flapping angle and torsional angle of a dragonfly wing  

Microsoft Academic Search

A fringe shadow (FS) method was developed for measuring the flapping angle and torsional angle of a dragonfly wing during beating motion. This new method involves two sets of fringe patterns projected onto the wing from orthogonal directions. The torsional angle is determined using the length of the shadow of the wing chord that is cast by the two sets

Lijiang Zeng; Hirokazu Matsumoto; Keiji Kawachi

1996-01-01

260

The Structure of Vitreous Carbon from Wide Angle and Low Angle X-Ray Diffraction.  

National Technical Information Service (NTIS)

Both wide angle and low angle X-ray diffraction patterns have been measured for a sample of vitreous carbon which has been subjected to maximum heat-treatment of 1800C. The wide angle scattering was used to calculate a radial distribution function, which ...

C. J. Pings G. D. Wignall

1972-01-01

261

[Effects of multi-angle hyperspectral polarized reflection by forest soil].  

PubMed

In the present study, the authors measured samples of typical forest soils in different states with multi-angle hyperspectral polarized reflections. The authors analyzed multi-angle hyperspectral polarized reflections of soil data with various viewing zenith angles, incidence angles, relative azimuth angles, polarized states, soil water content and soil granule. The authors found that those factors affected the reflectance values of forest soils but not the spectral feature. The conclusions included that the larger the incidence angles and viewing zenith angles are, the bigger the polarized reflectance values of the surface of the forest soil. When the forest soil was dry, the surface had phenomenon of diffuse reflection and the polarized light reflection did not take place. When the soil moisture content reached a certain level, the polarized reflection appeared. The more the moisture content of the forest soil was, the smaller the polarized reflectance of the surface. The bigger the soil granule was and the rougher the soil surface was, the smaller the surface polarized reflectance. The results and conclusions suggested that the spectral characteristics of the ground target need to be considered adequately in order to design the best mode for sensor systems by remote sensing technology. The authors suggest that the incidence angle and viewing zenith angle be selected on the basis of factual instance. The authors suggest using larger viewing zenith angles and that the incidence angle should be equal to the viewing zenith angle. In the meantime, the effects of sheltering by ground targets need to be considered and the proper state of polarization should be chosen while keeping relative zenith angle at 180 degrees. This study not only helps find a new way for detection of soil characters, but also provides a theoretical basis for further research on multi-angle hyperspectral polarized reflection for detecting characteristic spectrum and best states in measuring forest soil. PMID:19455804

Han, Yang; Zhao, Yun-Sheng; Zhao, Nai-Zhuo; Li, Qian; Lü, Yun-Feng

2009-03-01

262

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.

263

Solar angles revisited using a general vector approach  

SciTech Connect

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

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

2010-06-15

264

Why twisting angles are diverse in graphene Moiré patterns?  

NASA Astrophysics Data System (ADS)

The interlayer energy of the twisting bilayer graphene is investigated by the molecular mechanics method using both the registry-dependent potential and the Lennard-Jones potential. Both potentials show that the interlayer energy is independent of the twisting angle ?, except in the two boundary regions ?~0° or 60\\convolu, where the interlayer energy is proportional to the square of the twisting arc length. The calculation results are successfully interpreted by a single atom model. An important information from our findings is that, from the energy point of view, there is no preference for the twisting angle in the experimental bilayer graphene samples, which actually explains the diverse twisting angles in the experiment.

Jiang, Jin-Wu; Wang, Bing-Shen; Rabczuk, Timon

2013-05-01

265

Minimal neutrino texture with neutrino mass ratio and Cabibbo angle  

NASA Astrophysics Data System (ADS)

We present neutrino mass matrix textures in a minimal framework of the type-I seesaw mechanism, where two right-handed Majorana neutrinos are introduced in order to reproduce experimental results of neutrino oscillations. The textures can lead to experimentally favored leptonic mixing angles described by tri-bimaximal mixing with one additional rotation. We present minimal and next to minimal textures for the normal mass hierarchy case in the context of the texture zero. A minimal texture in the inverted hierarchy case is also constructed, which does not have any vanishing entries in a Dirac neutrino mass matrix. We also discuss some cases in which the model parameters in the textures are supposed to be a neutrino mass ratio and/or the Cabibbo angle. Predicted regions of mixing angles, a leptonic CP-violation parameter, and an effective mass for the neutrinoless double beta decay are presented in all textures.

Shimizu, Yusuke; Takahashi, Ryo; Tanimoto, Morimitsu

2013-06-01

266

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.

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

2012-01-01

267

Impact angles as an alternative way to improve aerosolisation of powders for inhalation?  

PubMed

This study aims to investigate the role of impact angles on the de-agglomeration performance of powders for inhalation. Agglomerates of a model drug mannitol were impacted at customized impaction throats containing two angles (15-75 degrees and 45-45 degrees) or a single angle (15 degrees, 45 degrees and 90 degrees) using various air flow rates. The mass fraction of fine particles <5microm in the aerosol (FPF(Loaded)) was measured by a liquid impinger coupled to a laser diffractometer. Results showed that for the two-angle throats, there existed an optimal angle (45 degrees) and air flow (120lmin(-1)) for the FPF(Loaded), resulting from a balance between improved de-agglomeration and enhanced throat deposition with increasing air flow. When the throat contained two equal angles of 45 degrees , most powder deposition occurred at the first angle, indicating that the first angle was likely to cause major de-agglomeration, while the second angle might act as a facilitator for further break-up, but the deposition was minimum as the fragment sizes and velocity at the second impaction were smaller. This hypothesis was supported by further studies using single-angle throats and numerical simulation (DEM-CFD). These findings imply the potential importance of using angular design features for multiple impactions to improve DPI performance. PMID:20615465

Adi, Santoso; Tong, Zhenbo; Chan, Hak-Kim; Yang, Runyu; Yu, Aibing

2010-07-06

268

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

2012-06-29

269

Minimal surfaces in S 3 with constant contact angle  

Microsoft Academic Search

We provide a characterization of the Clifford Torus in S3 via moving frames\\u000aand contact structure equations. More precisely, we prove that minimal surfaces\\u000ain S3 with constant contact angle must be the Clifford Torus. Some applications\\u000aof this result are then given, and some examples are discussed.

Rodrigo Ristow Montes; Jose A. Verderesi

2009-01-01

270

Minimal surfaces in S 3 with constant contact angle  

Microsoft Academic Search

We provide a characterization of the Clifford Torus in S\\u000a 3 via moving frames and contact structure equations. More precisely, we prove that minimal surfaces in S\\u000a 3 with constant contact angle must be the Clifford Torus. Some applications of this result are then given, and some examples\\u000a are discussed.

Rodrigo Ristow Montes; Jose A. Verderesi

2009-01-01

271

Minimal Surfaces in $S^3$ with Constant Contact Angle  

Microsoft Academic Search

We provide a characterization of the Clifford Torus in S3 via moving frames and contact structure equations. More precisely, we prove that minimal surfaces in S3 with constant contact angle must be the Clifford Torus. Some applications of this result are then given, and some examples are discussed.

Rodrigo Ristow Montes Jose A. Verderesi

2007-01-01

272

Small-angle x-ray scattering investigations of extrudates  

NASA Astrophysics Data System (ADS)

The small-angle X-ray scattering investigations of the extrudes are presented. The investigations of the different samples of starch by means of the SAXS indicate the new possibilities for using this method for extrudates examination. Results obtained by SAXS method of close dependance between intensity SAXS scattering and characteristic parameters of the extrudates were shown.

Pikus, Stanislaw; Jamroz, Jerzy

1997-02-01

273

Analysis and design of wide-angle foveated optical systems  

NASA Astrophysics Data System (ADS)

The development of compact imaging systems capable of transmitting high-resolution images in real-time while covering a wide field-of-view (FOV) is critical in a variety of military and civilian applications: surveillance, threat detection, target acquisition, tracking, remote operation of unmanned vehicles, etc. Recently, optical foveated imaging using liquid crystal (LC) spatial light modulators (SLM) has received considerable attention as a potential approach to reducing size and complexity in fast wide-angle lenses. The fundamental concept behind optical foveated imaging is reducing the number of elements in a fast wide-angle lens by placing a phase SLM at the pupil stop to dynamically compensate aberrations left uncorrected by the optical design. In the recent years, considerable research and development has been conducted in the field of optical foveated imaging based on the LC SLM technology, and several foveated optical systems (FOS) prototypes have been built. However, most research has been focused so far on the experimental demonstration of the basic concept using off-the-shelf components, without much concern for the practicality or the optical performance of the systems. Published results quantify only the aberration correction capabilities of the FOS, often claiming diffraction-limited performance at the region of interest (ROI). However, these results have continually overlooked diffraction effects on the zero-order efficiency and the image quality. The research work presented in this dissertation covers the methods and results of a detailed theoretical research study on the diffraction analysis, image quality, design, and optimization of fast wide-angle FOSs based on the current transmissive LC SLM technology. The amplitude and phase diffraction effects caused by the pixelated aperture of the SLM are explained and quantified, revealing fundamental limitations imposed by the current transmissive LC SLM technology. As a part of this study, five different fast wide-angle lens designs that can be used to build practical FOSs were developed, revealing additional challenges specific to the optical design of fast wide-angle systems, such as controlling the relative illumination, distortion, and distribution of aberrations across a wide FOV. One of the lens design examples was chosen as a study case to demonstrate the design, analysis, and optimization of a practical wide-angle FOS based on the current state-of-the-art transmissive LC SLM technology. The effects of fabrication and assembly tolerances on the image quality of fast wide-angle FOSs were also investigated, revealing the sensitivity of these fast well-corrected optical systems to manufacturing errors. The theoretical study presented in this dissertation sets fundamental analysis, design, and optimization guidelines for future developments in fast wide-angle FOSs based on transmissive SLM devices.

Curatu, George

274

Wide-angle vision for road views  

NASA Astrophysics Data System (ADS)

The field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.

Huang, F.; Fehrs, K.-K.; Hartmann, G.; Klette, R.

2013-03-01

275

The Viewing Angles of Broad Absorption Line versus Unabsorbed Quasars  

NASA Astrophysics Data System (ADS)

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° 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.; De Breuck, C.

2012-06-01

276

Angular Distributions of Sputtered Atoms from Semiconductor Targets at Grazing Ion Beam Incidence Angles  

SciTech Connect

Angular distributions of ion sputtered germanium and silicon atoms are investigated within this work. Experiments are performed for the case of grazing ion incidence angles, where the resulting angular distributions are asymmetrical with respect to the polar angle of the sputtered atoms. The performed experiments are compared to Monte-Carlo simulations from different programs. We show here an improved model for the angular distribution, which has an additional dependence of the ion incidence angle.

Sekowski, M. [Lehrstuhl fuer Elektronische Bauelemente, Cauerstrasse 6, 91058 Erlangen (Germany); Burenkov, A.; Martinez-Limia, A. [Fraunhofer Institut fuer Integrierte Systeme und Bauelementetechnologie (IISB), Schottkystrasse 10, 91058 Erlangen (Germany); Hernandez-Mangas, J. [Departamento Electricidad y Eletronica, Universidad de Valladolid, 47011 Valladolid (Spain); Ryssel, H. [Lehrstuhl fuer Elektronische Bauelemente, Cauerstrasse 6, 91058 Erlangen (Germany); Fraunhofer Institut fuer Integrierte Systeme und Bauelementetechnologie (IISB), Schottkystrasse 10, 91058 Erlangen (Germany)

2008-11-03

277

Fuzzy logic torque ripple reduction by turn-off angle compensation for switched reluctance motors  

Microsoft Academic Search

A fuzzy-logic-based turn-off angle compensator for torque ripple reduction in a switched reluctance motor is proposed. The turn-off angle, as a complex function of motor speed and current, is automatically changed for a wide motor speed range to reduce torque ripple. Experimental results are presented that show ripple reduction when the turn-off angle compensator is used

M. Rodrigues; P. J. Costa Branco; W. Suemitsu

2001-01-01

278

Superconducting Large-Angle Magnetic Suspension.  

National Technical Information Service (NTIS)

SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demon...

J. R. Downer G. V. Anastas D. A. Bushko F. J. Flynn J. H. Goldie

1992-01-01

279

Large Angle Transient Dynamics (LATDYN) User's Manual.  

National Technical Information Service (NTIS)

A computer code for modeling the large angle transient dynamics (LATDYN) of structures was developed to investigate techniques for analyzing flexible deformation and control/structure interaction problems associated with large angular motions of spacecraf...

A. L. Abrahamson C. Chang M. G. Powell S. Wu B. D. Bingel

1991-01-01

280

Open-angle glaucoma: diagnosis and management.  

PubMed

Open-angle glaucoma is not a benign disease; untreated, it can lead to total blindness. If intraocular tension is controlled early, before onset of visual field loss or optic nerve degeneration, the prognosis is good. PMID:6413360

Jindra, L F

1983-10-01

281

Nanofluid Surface Wettability Through Asymptotic Contact Angle.  

PubMed

This investigation introduces the asymptotic contact angle as a criterion to quantify the surface wettability of nanofluids and determines the variation of solid surface tensions with nanofluid concentration and nanoparticle size. The asymptotic contact angle, which is only a function of gas-liquid-solid physical properties, is independent of droplet size for ideal surfaces and can be obtained by equating the normal component of interfacial force on an axisymmetric droplet to that of a spherical droplet. The technique is illustrated for a series of bismuth telluride nanofluids where the variation of surface wettability is measured and evaluated by asymptotic contact angles as a function of nanoparticle size, concentration, and substrate material. It is found that the variation of nanofluid concentration, nanoparticle size, and substrate modifies both the gas-liquid and solid surface tensions, which consequently affects the force balance at the triple line, the contact angle, and surface wettability. PMID:21338112

Vafaei, Saeid; Wen, Dongsheng; Borca-Tasciuc, Theodorian

2011-02-21

282

Angled Sunshine, Seasons, and Solar Energy.  

ERIC Educational Resources Information Center

|Presents lessons with activities that integrate a science unit about seasons, energy from sunshine, and radiation from the sun, with a mathematics unit about angles and trigonometric functions. (ASK)|

Kim, Hy

1997-01-01

283

Disc haemorrhages, precursors of open angle glaucoma.  

PubMed

In a long-term study of 1270 patients with at least one of the findings, open-angle glaucoma, disc haemorrhages or retinal vein occlusions, disc haemorrhages were witnessed in approximately 20% of the cases with open-angle glaucoma, and were a precursor of glaucomatous disc changes and associated visual field defects. Disc haemorrhages also preceded a rising intraocular pressure (IOP) in the destructive process among open-angle glaucoma cases. Similar glaucomatous development appears among cases independent of IOP or detection of exfoliation syndrome. Retinal vein occlusions and disc haemorrhages behave similarly with respect to glaucoma. The large number of transgressions is an argument against dividing glaucoma into different types. These findings support a vascular genesis to open-angle glaucoma, presented in earlier epidemiological studies. PMID:11906810

Sonnsjö, Bo; Dokmo, Yvonne; Krakau, Torsten

2002-01-01

284

Contact angle hysteresis due to surface roughness  

Microsoft Academic Search

By means of the calculus of variations it is shown that even on rough surfaces the Young equation applies and that the Wenzel\\u000a equation relies on a false assumption. Contact angle hysteresis, i .e. the difference in the apparent advancing and receding\\u000a angles, for homogeneous rough solid substrates is due to the local slope of the solid surface at the

M. Brackel; F. De Bisschop; P. Joos

285

Classification and Treatment of Prominent Mandibular Angle  

Microsoft Academic Search

.   In Oriental culture, the contour of the mandibular angle is important for feminine facial shape because a woman who has a\\u000a wide and square face is thought to have had an unhappy life. A prominent mandibular angle, which does not coincide with the\\u000a natural look, produces a characteristic quadrangle, coarse, and muscular appearance. So Oriental women who have a

Seok Kwun Kim; Jae Jung Han; Jeong Tae Kim

2001-01-01

286

Disc haemorrhages, precursors of open angle glaucoma  

Microsoft Academic Search

In a long-term study of 1270 patients with at least one of the findings, open-angle glaucoma, disc haemorrhages or retinal vein occlusions, disc haemorrhages were witnessed in approximately 20% of the cases with open-angle glaucoma, and were a precursor of glaucomatous disc changes and associated visual field defects. Disc haemorrhages also preceded a rising intraocular pressure (IOP) in the destructive

Bo Sonnsjö; Yvonne Dokmo; Torsten Krakau

2002-01-01

287

Angular dependence of the electronic energy loss of 800-keV He ions along the Si{l_angle}100{r_angle} direction  

SciTech Connect

We present measurements of the stopping power of 800-keV {sup 4}He ions channeled along the Si{l_angle}100{r_angle} axis, as a function of the incidence angle. We compare the experimental results with theoretical calculations by using the impact-parameter-dependent energy loss obtained from the solution of the time-dependent Schr{umlt o}dinger equation through the coupled-channel method. This nonperturbative calculation provides reliable energy-loss results which are in good agreement with the experimental results. {copyright} {ital 1997} {ital The American Physical Society}

dos Santos, J.H.; Grande, P.L.; Behar, M.; Boudinov, H. [Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970, Porto Alegre (Brazil); Schiwietz, G. [Bereich F, Hahn-Meitner-Institut Berlin, Glienicker Strasse 100, D-14109 Berlin (Germany)

1997-02-01

288

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

Microsoft Academic Search

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

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

2011-01-01

289

Neutron spin echo scattering angle measurement (SESAME)  

SciTech Connect

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

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

2005-05-15

290

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

291

Boundary Layer Leading Edge Receptivity to Sound at Incidence Angles.  

NASA Astrophysics Data System (ADS)

The leading edge receptivity to acoustic waves of two-dimensional parabolic bodies was investigated using a spatial solution of the Navier-Stokes equations in vorticity/stream function form in parabolic coordinates. The free-stream is composed of a uniform flow with a superposed periodic velocity fluctuation of small amplitude. The method follows that of Haddad & Corke(J. Fluid Mech.), 368, 1998 in which the solution for the basic flow and linearized perturbation flow are solved separately. We primarily investigated the effect of frequency and angle of incidence (-180^circ <= ? <= 180^circ) of the acoustic waves on the leading edge receptivity. The results at ?=0^circ were found to be in quantitative agreement with those of Haddad & Corke, and substantiated the Strouhal number scaling based on the nose radius. The results with sound waves at angles of incidence agreed qualitatively with the analysis of Hammerton & Kerschen (1992). These included a maximum receptivity at ?=90^circ, and an asymmetric variation in the receptivity with sound incidence angle, with minima at angles which were slightly less than ?=0^circ and 180^circ.

Erturk, E.; Corke, T. C.

1999-11-01

292

The effect of viewing angle on wrist posture estimation from photographic images using novice raters.  

PubMed

Observational assessment of wrist posture using photographic methods is theoretically affected by camera view angle. A study was conducted to investigate whether wrist flexion/extension and radial/ulnar deviation postures were estimated differently by raters depending on the viewing angle and compared to predictions using a quantitative 2D model of parallax. Novice raters (n=26) estimated joint angles from images of wrist postures photographed from ten different viewing angles. Results indicated that ideal views, orthogonal to the plane of motion, produced more accurate estimates of posture compared to non-ideal views. The neutral (0°) posture was estimated the most accurately even at different viewing angles. Raters were more accurate than model predictions. Findings demonstrate a need for more systematic methods for collecting and analyzing photographic data for observational studies of posture. Renewed caution in interpreting existing studies of wrist posture where viewing angle was not controlled is advised. PMID:21296336

Lau, Michael H; Armstrong, Thomas J

2011-02-05

293

A model and simulation to predict the performance of angle-angle-range 3D flash ladar imaging sensor systems  

NASA Astrophysics Data System (ADS)

BAE SYSTEMS reports on a program to develop a high-fidelity model and simulation to predict the performance of angle-angle-range 3D flash LADAR Imaging Sensor systems. 3D Flash LADAR is the latest evolution of laser radar systems and provides unique capability in its ability to provide high-resolution LADAR imagery upon a single laser pulse; rather than constructing an image from multiple pulses as with conventional scanning LADAR systems. However, accurate methods to model and simulate performance from these 3D LADAR systems have been lacking, relying upon either single pixel LADAR performance or extrapolating from passive detection FPA performance. The model and simulation developed and reported here is expressly for 3D angle-angle-range imaging LADAR systems. To represent an accurate "real world" type environment, this model and simulation accounts for: 1) laser pulse shape; 2) detector array size; 3) atmospheric transmission; 4) atmospheric backscatter; 5) atmospheric turbulence; 6) obscurants, and; 7) obscurant path length. The angle-angle-range 3D flash LADAR model and simulation accounts for all pixels in the detector array by modeling and accounting for the non-uniformity of each individual pixel in the array. Here, noise sources are modeled based upon their pixel-to-pixel statistical variation. A cumulative probability function is determined by integrating the normal distribution with respect to detector gain, and, for each pixel, a random number is compared with the cumulative probability function resulting in a different gain for each pixel within the array. In this manner very accurate performance is determined pixel-by-pixel. Model outputs are in the form of 3D images of the far-field distribution across the array as intercepted by the target, gain distribution, power distribution, average signal-to-noise, and probability of detection across the array. Other outputs include power distribution from a target, signal-to-noise vs. range, probability of target detection and identification, and NEP vs. gain.

Grasso, Robert J.; Odhner, Jefferson E.; Russo, Leonard E.; McDaniel, Robert V.

2004-11-01

294

A model and simulation to predict the performance of angle-angle-range 3D flash LADAR imaging sensor systems  

NASA Astrophysics Data System (ADS)

BAE SYSTEMS reports on a program to develop a high-fidelity model and simulation to predict the performance of angle-angle-range 3D flash LADAR Imaging Sensor systems. 3D Flash LADAR is the latest evolution of laser radar systems and provides unique capability in its ability to provide high-resolution LADAR imagery upon a single laser pulse; rather than constructing an image from multiple pulses as with conventional scanning LADAR systems. However, accurate methods to model and simulate performance from these 3D LADAR systems have been lacking, relying upon either single pixel LADAR performance or extrapolating from passive detection FPA performance. The model and simulation developed and reported here is expressly for 3D angle-angle-range imaging LADAR systems. To represent an accurate "real world" type environment, this model and simulation accounts for: 1) laser pulse shape; 2) detector array size; 3) atmospheric transmission; 4) atmospheric backscatter; 5) atmospheric turbulence; 6) obscurants, and; 7) obscurant path length. The angle-angle-range 3D flash LADAR model and simulation accounts for all pixels in the detector array by modeling and accounting for the non-uniformity of each individual pixel in the array. Here, noise sources are modeled based upon their pixel-to-pixel statistical variation. A cumulative probability function is determined by integrating the normal distribution with respect to detector gain, and, for each pixel, a random number is compared with the cumulative probability function resulting in a different gain for each pixel within the array. In this manner very accurate performance is determined pixel-by-pixel. Model outputs are in the form of 3D images of the far-field distribution across the array as intercepted by the target, gain distribution, power distribution, average signal-to-noise, and probability of detection across the array. Other outputs include power distribution from a target, signal-to-noise vs. range, probability of target detection and identification, and NEP vs. gain.

Grasso, Robert J.; Odhner, Jefferson E.; Russo, Leonard E.; McDaniel, Robert V.

2005-10-01

295

Angle amplifier based on multiplexed volume holographic gratings  

Microsoft Academic Search

Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of

Liangcai Cao; Yifei Zhao; Qingsheng He; Guofan Jin

2008-01-01

296

FDTD calculations of the divergence angle of multi-mode VCSELs  

NASA Astrophysics Data System (ADS)

We describe and demonstrate a method of decreasing the divergence angle of multi-mode VCSELs, and show how we can obtain a low and stable divergence angle. We first explain the relationship between the lateral wave-vectors of resonant modes and the divergence angle. Then we attempt to optimize the oxide aperture and the electrode structure. Here, we calculate the electro-magnetic field of the VCSELs by the Finite Difference Time Domain (FDTD) method and the far-field pattern by combining the diffraction integral and the FDTD. Finally, we compare the theoretical and experimental results of the divergence angle of the VCSELs.

Mochizuki, Masamitsu; Nishida, Tetsuo; Kakinuma, Satoshi; Kaneko, Takeo

2005-04-01

297

Technique to measure contact angle of micro/nanodroplets using atomic force microscopy  

SciTech Connect

Contact angle is the primary parameter that characterizes wetting; however, the measurement techniques have been limited to droplets with a diameter as low as about 50 {mu}m. The authors developed an atomic force microscopy-based technique to measure the contact angle of micro- and nanodroplets deposited using a modified nanoscale dispensing tip. The obtained contact angle results were compared with those of a macrodroplet (2.1 mm diameter). It was found that the contact angle on various surfaces decreases with decreasing the droplet size.

Jung, Yong Chae; Bhushan, Bharat [Nanotribology Laboratory for Information Storage and MEMS/NEMS (NLIM), 201 W. 19th Avenue, Ohio State University, Columbus, Ohio 43210-1142 (United States)

2008-07-15

298

[Studies of the thermal radiation multi-angle polarization properties of snow].  

PubMed

This paper, catering to the need of the study of remote sensing for thermal radiation polarization properties of ground features, detects the thermal radiation multi-angle polarization properties of snow, and makes analysis of effects of four factors, i. e. detecting zenith angle, detecting azimuth angle, bands and polarizing angle, on the thermal radiation properties of snow. The results show that the radiance and brightness temperature of snow increases with the detecting zenith angle. When the detecting zenith angle is greater than 30 degrees, the growth accelerated, and the effect of detecting zenith angle on the brightness temperature of snow is more significant than that of the radiance; the changes in detecting azimuth angle have some effect on the radiance and brightness temperature of snow, and have much influence on the brightness temperature than that of the radiance; the radiance and brightness temperature of snow is significantly affected by the changes in bands, and the effect on the radiance is more significant; the changes in polarizing angle have some effect on the radiance and brightness temperature of the snow, and have much influence on its brightness temperature. The results of the study provide new ideas and methods for the application of remote sensing technology to carrying out the thermal infrared quantitative study of snow, and have important theoretical significance and potential applications. PMID:23586253

Zhang, Xia; Zhao, Yun-Sheng; Sun, Tian-Lin; Shi, Jun; Liu, Jie

2013-01-01

299

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

SciTech Connect

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

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

1999-10-14

300

The gonial angle stripper: an instrument for the treatment of prominent gonial angle.  

PubMed

In the Orient, a prominent gonial angle, so-called benign masseteric hypertrophy, is rather common and considered unattractive. Therefore, its surgical correction is one of the most popular forms of facial skeletal contouring. For accurate and safe osteotomy of the mandibular angle region, a gonial angle stripper was specially invented. It has a small projection that will ease identification of the osteotomy line in a narrow operative field. The tool has been clinically used in eight patients to prove its usefulness, especially for a posteriorly developed mandibular angle. PMID:7880065

Kyutoku, S; Yanagida, A; Kusumoto, K; Ogawa, Y

1994-12-01

301

Broadband "Infinite-Speed" Magic-Angle Spinning NMR Spectroscopy  

SciTech Connect

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

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

2009-06-02

302

Improving gated cardiac scanning using limited-angle reconstruction technique  

SciTech Connect

Selected phases of the cardiac cycle can be imaged by the method of gated cardiac scanning using whole body scanners. However, since there is no synchronization between the random heart beats and the CT machine, the output will have gaps in the angular coverage of each scan. The missing projections in these gaps result in artifacts in the reconstructed images. In this paper, the technique of limited-angle reconstruction is employed to fill in the missing projections to remove the artifacts. The object is transformed back and forth between the object space and the projection space, being corrected in each step by the constraints of the finite spatial extent and of the upper and lower bounds of the object in the object space, and the known projections in the projection space. It is found that by using the proposed algorithm the rms errors of the limited-angle images are reduced to a level comparable to those of the complete-angle images. The same iteration algorithm can also be used to reduce the fan beam scanning angle from 360 degree to 180 degree without sacrificing much image quality.

Tam, K.C.; Perez-Mendez, V.

1983-02-01

303

Multiwavelength imaging polarimetry of Venus at various phase angles  

NASA Astrophysics Data System (ADS)

Venus is the only planet with an atmosphere that we can observe from the ground at a large range of phase angles. Therefore it constitutes an important benchmark for direct observations of exoplanets, which will soon become available. Moreover, polarimetric observations at various phase angles and wavelengths provide a unique way to characterize any (exo-)planetary atmosphere. For instance, the famous study by Hansen & Hovenier (1974) which combines disk-integrated polarimetric observations and modeling has unambiguously shown that Venus' upper atmosphere consists of sulphuric acid droplets of ~1 um in diameter. We present new spatially resolved observations of Venus using the imaging polarimeters ExPo at the William Herschel Telescope and ZIMPOL at the IRSOL telescope. These observations are taken in narrow-band filters from 364--648 nm, and span phase angles from 10--49 degrees. We find that the degree of polarization varies strongly with wavelength and phase angle, as generally predicted by the model by Hansen & Hovenier. However, the polarization behaviour near the equator differs considerably from that at the poles, hinting at different atmospheric compositions and/or stratifications. In the intensity images we detect a significant shift of the location of maximum intensity with wavelength. These observations allow us to refine the model by Hansen & Hovenier, and we present the preliminary results of our efforts to do so.

Einarsen, L. J.; Rodenhuis, M.; Snik, F.; Keller, C. U.; Stam, D. M.; de Kok, R. J.; Bianda, M.; Ramelli, R.

2012-04-01

304

Diffraction by polyhedral angle: Field in vicinity of singular ray  

NASA Astrophysics Data System (ADS)

If the plane acoustic wave hits a polyhedral angle, the scattered field consists of an incident wave, of its reflections from the angle's facets, of primary edge waves excited at angle's edges, and of a spherical wave excited at the angle's vertex. It is supposed for simplicity that the geometry of the problem is such that there is no secondary and subsequent edge waves. There are two types of light-shadow boundaries: first for incident and reflected waves and second for edge waves. As is well known, the field in penumbras is expressed via a Fresnel integral. The incident wave's ray passing through the vertex and its reflections from facets are singular rays belonging to the light-shadow boundaries of both types. It will be shown that the field in the vicinity of a singular ray is expressed via a Fresnel intergal and via a generalized Fresnel integral G(p,q) which was introduced in [P. S. Clemmov and T. B. A. Senior, Proc. Cambridge Philos. Soc. 9, 570-572 (1953); see also V. A. Borovikov, Uniform Stationary Phase Method, IEE Electromagnetic Series 40, London, 1994]. This result is valid for an elastic incident wave as well.

Borovikov, Vladimir A.

2002-11-01

305

Direction Angle Sensitivity of Agricultural Field Backscatter with AIRSAR Data.  

National Technical Information Service (NTIS)

This paper presents a study of the direction angle sensitivity of radar backscatter from agricultural fields. The direction angle is defined as the angle between the incident plane and the perpendicular to the field row direction. Previous studies have co...

P. C. Dubois E. Rignot J. J. Vanzyl

1993-01-01

306

Biomarkers in primary open angle glaucoma.  

PubMed

Glaucoma, a leading cause of blindness worldwide, is currently defined as a disturbance of the structural or functional integrity of the optic nerve that causes characteristic atrophic changes in the optic nerve, which may lead to specific visual field defects over time. This disturbance usually can be arrested or diminished by adequate lowering of intraocular pressure (IOP). Glaucoma can be divided roughly into two main categories, ‘ open angle ’ and ‘ closed angle ’ glaucoma.Open angle, chronic glaucoma tends to progress at a slower rate and patients may not notice loss of vision until the disease has progressed significantly. Primary open angle glaucoma(POAG) is described distinctly as a multifactorial optic neuropathy that is chronic and progressive with a characteristic acquired loss of optic nerve fibers. Such loss develops in the presence of open anterior chamber angles, characteristic visual field abnormalities, and IOP that is too high for the healthy eye. It manifests by cupping and atrophy of the optic disc, in the absence of other known causes of glaucomatous disease. Several biological markers have been implicated with the disease. The purpose of this study was to summarize the current knowledge regarding the non-genetic molecular markers which have been predicted to have an association with POAG but have not yet been validated. PMID:22745021

Kokotas, Haris; Kroupis, Christos; Chiras, Dimitrios; Grigoriadou, Maria; Lamnissou, Klea; Petersen, Michael B; Kitsos, George

2012-12-01

307

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

SciTech Connect

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

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

1992-12-01

308

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.

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

2008-01-01

309

System for determining the angle of impact of an object on a structure  

Microsoft Academic Search

A method for determining the angle of impact of an object on a thin-walled structure which determines the angle of impact through analysis of the acoustic waves which result when an object impacts a structure is presented. Transducers are placed on and in the surface of the structure which sense the wave caused in the structure by impact. The waves

William H. Prosser; Michael R. Gorman

1993-01-01

310

System for determining the angle of impact of an object on a structure  

Microsoft Academic Search

A method for determining the angle of impact of an object on a thin-walled structure which determines the angle of impact through analysis of the acoustic waves which result when an object impacts a structure is presented. Transducers are placed on and in the surface of the structure which sense the wave caused in the structure by impact. The waves

William H. Prosser; Michael R. Gorman

1992-01-01

311

An Investigation of the Flow About an Ogive Cylinder at High Angles of Incidence.  

National Technical Information Service (NTIS)

The present work gives the results of flow visualization studies and six component force measurements on an ogive cylinder body at high angles of attack in the sub and transonic flow regime. High angle of attack aerodynamic investigations had not been don...

B. P. Paul E. Wedemeyer

1982-01-01

312

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

313

Detection of Occludable Angles with the Pentacam and the Anterior Segment Optical Coherence Tomography  

PubMed Central

Purpose To assess efficacy of the Pentacam (PTC) and the anterior segment optical coherence tomography (AOCT) for detection of occludable angles. Materials and Methods Fourty-one eyes with gonioscopically diagnosed occludable angles and 32 normal open-angle eyes were included. Anterior chamber angle (ACA) and anterior chamber depth (ACD) were measured with PTC and AOCT. Receiver operating characteristic (ROC) curve was constructed for each parameter and the area under the ROC curve (AUC) was calculated. Results Values of ACA and ACD measured by PTC and AOCT were similar not only in normal open angle eyes but also in occludable angle eyes. For detection of occludable angle, the AUCs of PTC with ACA and ACD were 0.935 and 0.969, respectively. The AUCs of AOCT with ACA and ACD were 0.904 and 0.947, respectively. Conclusion Both PTC and AOCT allow accurate discrimination between open and occludable angle eyes, so that they may aid to screening the occludable angles.

Hong, Samin; Yi, Jeong-Ho; Kang, Sung Yong; Seong, Gong Je

2009-01-01

314

Calcified vestibular schwannoma in the cerebellopontine angle.  

PubMed

Although vestibular schwannoma is a common tumor in the cerebellopontine angle, calcified vestibular schwannoma is rare. A 59-year-old woman with sudden onset epileptic seizures, was referred to Hokkaido Neurosurgical Memorial Hospital. Neurological examination revealed left Bruns nystagmus, left deafness and left cerebellar ataxia. Brain MRI revealed a mass, about 3cm in diameter, in the left cerebellopontine angle. The mass showed heterogeneous intensity on T1- and T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Hydrocephalus was seen. On CT scan, the tumor was calcified. Preoperatively, vestibular schwannoma, meningioma, cavernous hemangioma, or thrombosed giant aneurysm were considered as differential diagnoses. The pathological diagnosis was schwannoma. For a calcified mass in the cerebellopontine angle, vestibular schwannoma should be considered in the differential diagnosis to plan appropriate treatment strategies. PMID:17884507

Katoh, Masahito; Aida, Toshimitsu; Imamura, Hiroyuki; Aoki, Takeshi; Yoshino, Masami; Kashiwazaki, Daina; Takei, Hidetoshi

2007-09-19

315

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

316

Fluctuating flow angles and anisotropic flow measurements  

NASA Astrophysics Data System (ADS)

Event-by-event fluctuations in the initial density distributions of the fireballs created in relativistic heavy-ion collisions lead to event-by-event fluctuations of the final anisotropic flow angles, and density inhomogeneities in the initial state cause these flow angles to vary with the transverse momentum of the emitted particles. It is shown that these effects lead to characteristically different transverse momentum dependencies for anisotropic flow coefficients extracted from different experimental methods. These differences can be used to experimentally constrain flow angle fluctuations in the final state of heavy-ion collisions which, in turn, are sensitive to the initial-state density fluctuations and the shear viscosity of the expanding fireball medium.

Heinz, Ulrich; Qiu, Zhi; Shen, Chun

2013-03-01

317

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

318

Effects of incidence angle on observations of equilibrium crater diameter  

NASA Astrophysics Data System (ADS)

Determining the equilibrium crater diameter for a crater population is important in lunar regolith depth estimates as the equilibrium diameter represents the steady-state between the formation of new craters and the removal of older craters [1]. [2] hypothesized that the number of craters identified in an image is dependent on the incidence angle and showed that for three different young mare regions, fewer craters are visible at lower incidence angles, affecting reliable estimates of the equilibrium diameter of the counted crater population. [3] disputed this hypothesis and the presence of an equilibrium crater population in the data from [2]. Testing the hypothesis from [2], we chose four Apollo Metric images of the same area with different incidence angles to examine the effects of resolution on apparent equilibrium diameter estimates. We selected a 100 km2 area centered at 27.3°N, 18.2°W in Mare Imbrium east of Lambert crater with data at 87°, 82°, 71°, and 50° incidence angles, and scan resolutions of 6.6 to 7.6 m/pixel. To compare the craters visible at different illuminations, we resampled the images to 10 m/pixel and employed three individuals to count craters. The cumulative histograms for the four Apollo Metric frames exhibit the effects of different incidence angles on reliably counting craters. Current results show that the crater counts for the 82° incidence angle image are the most consistent between different observers, finding a production function slope of -4.1 and an apparent equilibrium diameter of 200 m. Deviation from the small crater trends (equilibrium population?) and the production function slope observed at 82° incidence is found at the higher (87°) and lower (71°, 50°) incidence angles. We attribute some of this deviation to the effects of incidence angle on crater detection; at crater diameters >~300 m, we find similar production functions, an observation consistent with our identification of these large craters in all four illuminations. However, the small crater trends vary significantly among observations at different illuminations. An important question is whether the small crater slope and rollover we observe are representative of the equilibrium crater population or whether these observations are due to resolution limits of the images, a too-small count area, or shadow effects (e.g., loss of small craters in the shadows of larger craters). To test if the observed rollover in the cumulative histograms is due to resolution effects or to the observation of the equilibrium crater population, we will use substantially higher resolution images. Images from the Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (resolution increasing during the nominal mission from ~1.5 to ~0.5 m/pixel) at incidence angles ranging from 50° to 87°, focusing on higher incidences (70° to 87°), will be used to maximize the identification of small craters. [1] L. A. Soderblom (1970) JGR, 75, 2655. [2] B. B. Wilcox et al. (2005) Meteoritics & Plan. Sci., 40, 695. [3] V. R. Oberbeck (2008) Meteoritics & Plan. Sci., 43, 815.

Ostrach, L. R.; Denevi, B. W.; Hastings, A.; Koeber, S.; Robinson, M. S.; Thomas, P. C.; Tran, T. N.

2009-12-01

319

Low back pain and lumbar angles in Turkish coal miners  

SciTech Connect

This study was designed to assess the incidence of low back pain among Turkish coal miners and to investigate the relationship between angles of the lumbar spine and low back pain in coal miners. Fifty underground workers (Group I) and 38 age-matched surface workers (Group II) were included in the study. All the subjects were asked about low back pain in the past 5 years. The prevalence of low back pain was higher in Group I than in Group II (78.0%, 32.4%, respectively, P {lt} 0.001). The results of the study showed that low back pain occurred in 78.0% of Turkish coal miners. Although the nature of the occupation may have influenced coal miners' lumbar spinal curvature, lumbar angles are not a determinant for low back pain in this population. Further extensive studies involving ergonomic measurements are needed to validate our results for Turkish coal mining industry.

Sarikaya, S.; Ozdolap, S.; Gumustas, S.; Koc, U. [Zonguldak Karaelmas University, Zonguldak (Turkey). Faculty of Medicine

2007-02-15

320

Bohler's and Gissane Angles in the Indian Population  

PubMed Central

Objective: The aim of our study is to determine the normal ranges of the calcaneal parameters in the Indian population, and to compare the results with the data in the literature. Materials and Methods: The study was conducted at Coimbatore Medical College Hospital, Coimbatore on the feet (324 in number) of male and female Indian adults. Lateral view of the ankle was taken using a digital X-ray machine. Two parameters namely Bohler`s and Gissane angles were measured, independently by two radiologists to prevent inter-observer variation. Results: The Bohler`s and Gissane angles for the Indian population are statistically different from those seen in the published data for other population groups, as evidenced by the P value (P < 0.05). Conclusion: Calcaneal parameters specific to the Indian population have to be taken into consideration by the orthopedic surgeon to improve the standard of calcaneal fracture treatment in India.

Sengodan, Vetrivel C.; Amruth, K. H.; Karthikeyan

2012-01-01

321

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

NASA Astrophysics Data System (ADS)

Numerical simulation of the flow around an air data sensor (ADS), which measures flow angles and Mach numbers using surface pressures on a nose cone, was conducted in this study. Effects of the half-cone angle on the flow angle and Mach number measurements were investigated. Results show that a large half-cone angle achieves high sensitivity of flow angle measurements. Results further demonstrated that a small half-cone angle achieves high-sensitivity of Mach number measurements. To satisfy these conflicting requests, we proposed the use of bi-conic nose cones with two gradients. High sensitivity was achieved for both flow angle measurements and Mach number measurements using this bi-conic nose cone.

Fukiba, Katsuyoshi; Tsuboi, Nobuyuki; Kobayashi, Hiroaki

322

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.

323

A new three-angle energy-dispersive diffractometer  

NASA Astrophysics Data System (ADS)

A novel energy-dispersive diffractometer has been designed in which diffraction patterns can be collected simultaneously at three angles. This results in a much wider overall coverage of reciprocal space and a matching of the X-ray source and detection system to chosen regions of a pattern so that quantitative analysis is considerably enhanced. We predict a wide acceptance of the technique for in situ studies and multi-phase analysis.

Barnes, P.; Jupe, A. C.; Colston, S. L.; Jacques, S. D.; Grant, A.; Rathbone, T.; Miller, M.; Clark, S. M.; Cernik, R. J.

1998-02-01

324

The 2mrad Crossing Angle Interaction Region and Extraction Line  

SciTech Connect

A complete optics design for the 2mrad crossing angle interaction region and extraction line was presented at Snowmass 2005. Since this time, the design task force has been working on developing and improving the performance of the extraction line. The work has focused on optimizing the final doublet parameters and on reducing the power losses resulting from the disrupted beam transport. In this paper, the most recent status of the 2mrad layout and the corresponding performance are presented.

Appleby, R.; U., Manchester; Angal-Kalinin, D.; /Cockcroft Inst. Accel. Sci. Tech; Dadoun, O.; Bambade, P.; /Orsay, LAL; Parker, B.; /Brookhaven; Keller, L.; Moffeit, K.; Nosochkov, Y.; Seryi, A.; Spencer, C.; /SLAC; Carter, J.; Royal Holloway, U.of London; Napoly, O.; /DAPNIA, Saclay

2006-07-12

325

Superconducting Large-Angle Magnetic Suspension.  

National Technical Information Service (NTIS)

The component technologies were developed required for an advanced control moment gyro (CMG) type of slewing actuator for large payloads. The key component of the CMG is a large-angle magnetic suspension (LAMS). The LAMS combines the functions of the gimb...

J. Downer J. Goldie R. Torti

1991-01-01

326

Mie Scattering Near the Critical Angle.  

National Technical Information Service (NTIS)

Complex angular momentum theory is applied to the problem of high-frequency critical light scattering by a spherical cavity near the critical angle. The main contributions to the scattering arise from a critical domain close to critical incidence. The res...

N. Fiedler-Ferrari H. M. Nussenzveig

1987-01-01

327

Effect of Peel Angle on Peel Force.  

National Technical Information Service (NTIS)

Measurements of peel force P per unit width are reported for samples of three adhesive tapes, adhering to two different substrates. In all cases, the work of detachment per unit area of bonded interface was found to depend upon the angle theta of detachme...

R. S. Miller

1987-01-01

328

Labelling Angles: Care, Indifference and Mathematical Symbols  

ERIC Educational Resources Information Center

|In this article, I explore tensions of care in the context of school mathematics by examining two accounts of a classroom moment involving labelling an angle. In particular, I draw attention to how caring for students and caring for mathematical ideas interplay in complex ways by inquiring into the two accounts through ideas of care and…

Long, Julie

2011-01-01

329

Partitioning Pythagorean Triangles Using Pythagorean Angles  

ERIC Educational Resources Information Center

|Inside any Pythagorean right triangle, it is possible to find a point M so that drawing segments from M to each vertex of the triangle yields angles whose sines and cosines are all rational. This article describes an algorithm that generates an infinite number of such points.|

Swenson, Carl E.; Yandl, Andre L.

2012-01-01

330

Charge collection at large angles of incidence  

Microsoft Academic Search

Charge collection exhibited by p-n junctions, which have at least one small dimension, deviates from the geometric assumptions commonly used in SEU (single event upset) testing. The amount of charge collected did not increase with the secant of the angle of incidence. The number of events under the peak in the charge collection spectrum did not decrease as the cosine

P. J. McNulty; W. J. Beauvais; R. A. Reed; D. R. Roth; E. G. Stassinopoulos; G. J. Brucker

1992-01-01

331

Resistance angle sensor based tree diameter gauge  

Microsoft Academic Search

Accurate measurement of the tree diameter is important for the production and scientific research of forestry. The paper developed a resistance angle sensor based on tree diameter gauge, which provided a resolution to some difficulties in tree diameter measuring, such as big trees and trees with spine. The height measuring module based on ultrasonic sensor made it easy to find

Feng Zhi-hui; Chen Wei-mian; Shen Jin-feng; Fang Yi-ming

2010-01-01

332

A mobilized dilation angle model for rocks  

Microsoft Academic Search

Experimental and field observations of rock failure show that the failure process is closely associated with rock dilation, an indicator of volumetric increase during rock deformation. The most common concept used to describe dilation is the dilation angle. The conventional Mohr–Coulomb model considering strain-softening often makes an assumption of constant dilation, but it is observed that the approach is not

X. G. Zhao; M. Cai

2010-01-01

333

Wide-Angle Nuclear Detection Array (WANDA)  

Microsoft Academic Search

The Wide-Angle Nuclear Detection Array (WANDA) is a data analysis system that uses an array of detectors to act as a coincidence detection system, utilizes a database of possible radioisotopes, and searches this database using a physics-based analysis to identify the source type and location that best accounts for the measured Compton scattering data. This method has the ability to

Timothy Doyle; Raymond DeVito

2010-01-01

334

A wide-angle scanning optical antenna  

Microsoft Academic Search

The design of a modified Rinehart metal dome antenna with a dielectric ring lens at the output edge is discussed. This antenna provides wide-angle scanning of a narrow beam. The dome shape, which provides perfect focus in the plane of scan, is determined by solving an integral equation. The dielectric lens focuses in the plane perpendicular to the plane scan,

E. C. Dufort; H. Uyeda

1983-01-01

335

Small-Angle Scattering Functions of Micelles  

Microsoft Academic Search

Models for small-angle scattering of spherical micelles are briefly reviewed, considering both the intra- molecular form factor and the inter-molecular structure factor. Recent examples from the literature, where such approaches have been used to extract information on micellar structure and ordering, are then discussed. A particular emphasis is on micelles formed by block copolymers in solution.

V. Castelletto; I. W. Hamley

336

Decoding low dihedral angles in gabbroic layered intrusions  

NASA Astrophysics Data System (ADS)

Texturally equilibrated rocks are granular with a unimodal grain size, smoothly curved grain boundaries, and angles at three-grain junctions of 110-140°. Gabbros are not texturally equilibrated: primocrysts commonly have planar faces whereas later-formed phases fill in the interstitial spaces. Augite-plagioclase-plagioclase dihedral angles (?cpp) rarely attain the equilibrium value in gabbros and the population of disequilibrium angles preserves otherwise inaccessible information about rock history. The ?cpp population varies significantly between different basaltic bodies. In a rapidly cooled dolerite ?cpp has a low median (60-70°) and a high standard deviation (20-25°). The plagioclase-augite grain boundaries are generally planar. In more slowly cooled gabbros in layered intrusions, the angle populations have a higher median (80-110°) with a low standard deviation (10-15°). The plagioclase-augite grain boundaries are generally planar far from the triple junction, but curve within 10 microns of the junction. This curvature is commonly asymmetric. The angle population in solidified gabbros infiltrated by low-temperature melts is similar to that in dolerites, although the low angles are associated with cuspate interstitial grains. The dihedral angle is a function of both the original solidification process and subsequent high-temperature (melt-absent) grain boundary migration. Infilling of a melt pocket by overgrowth of the bounding solid phases necessitates supersaturation, and this is easier to attain for planar faces, resulting in inhibition of augite growth into pores bounded by planar plagioclase grains and an asymmetry of the initial augite-plag-plag junction. If the solidified gabbro is kept sufficiently hot these initial junction geometries can change during textural equilibration. In the Skaergaard, Rum and Bushveld intrusions, the median ?cpp varies with liquidus assemblage, increasing step-wise on the addition of a new liquidus phase. Locally, these steps are offset relative to the arrival of the new phase, inconsistent with a compositional control. It is more likely that the control is due to step-wise changes in the fractional latent heat. During solidification the temperature of the liquid-bearing parts of a fractionating intrusion is partially buffered by crystallisation. An increase in the fractional latent heat associated with a new liquidus phase decreases the rate at which the magma temperature drops. Although the step-wise changes in ?cpp may be a result of changes in the extent of sub-solidus textural equilibration, it is also possible that the different angle populations are an original feature formed during solidification, via a control by cooling rate on the supersaturation required to overgrow the pore walls. The dihedral angle, combined with other textural features such as grain boundary curvature, is a useful indicator of magma chamber processes. It can be used to detect changes in liquidus assemblage in fractionating gabbros when more conventional indicators (e.g. grain shape or modal assemblage) don’t provide conclusive answers, and to constrain the spatial extent of late-stage infiltration when traditional chemical traces are absent.

Holness, M. B.; Humphreys, M.; Veksler, I. V.

2010-12-01

337

Characterizing the combinatorial beam angle selection problem  

NASA Astrophysics Data System (ADS)

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

Bangert, Mark; Ziegenhein, Peter; Oelfke, Uwe

2012-10-01

338

The Lateral Angle Revisited: A Validation Study of the Reliability of the Lateral Angle Method for Sex Determination Using Computed Tomography (CT)(,).  

PubMed

This article presents the results of a validation study of a previously published method of sex determination from the temporal bone. The purpose of this study was to evaluate the lateral angle method for the internal acoustic canal for accurately determining the sex of human skeletal remains using measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability. The mean lateral angle of the internal acoustic canal was found to be larger in females (46.5°) than in males (43.4°). However, the difference was not statistically significant and the sex differences reported in previous studies were not substantiated. In light of the observed results, the lateral angle method appears to be of minimal practical use in forensic anthropology and archeology. PMID:23406531

Morgan, Jennifer; Lynnerup, Niels; Hoppa, Robert D

2013-02-13

339

Analytic solution of GPS atmospheric sounding refraction angles  

Microsoft Academic Search

The nonlinear system of equations for solving GPS atmospheric sounding's bending angles are normally solved using Newton's method. Because of the nonlinear nature of the equations, Newton's method applies linearization and iterations. The method assumes the refraction angle to be small enough such that the dependency of the doppler shift on these angles are linear. The bending angles are then

J. L. Awange; Yoichi Fukuda; Shuzo Takemoto; Jens Wickert; Yuichi Aoyama

2004-01-01

340

Climatic controls on hillslope angle and relief in the Himalayas  

Microsoft Academic Search

Comparison of rainfall data and mean hillslope angles in the Himalayas of central Nepal shows that mean hillslope angles decrease with increasing mean annual rainfall. Higher pore pressures and higher rates of chemical weathering in the wetter regions may decrease the threshold angle of hillslopes prone to landsliding. When valley spacing is held constant, the sensitivity of mean hillslope angle

Emmanuel J. Gabet; Beth A. Pratt-Sitaula; Douglas W. Burbank

2004-01-01

341

Range and resolution analysis of wide-azimuth angle decomposition  

Microsoft Academic Search

Imaging in complex media benefits from uniform illumination of the target from all possible directions. Moreover, it is desirable to recover reflectivity from seismic data as a function of incidence and azimuthal angles at every location over the reflector. Ap- plications of angle-dependent reflectivity include velocity and anisotropy estimation and amplitude versus angle (AVA) analysis. One way of constructing angle-dependent

Gabriela Melo; Paul Sava

2008-01-01

342

Sunspot group tilt angles and the strength of the solar cycle  

NASA Astrophysics Data System (ADS)

Context. It is well known that the tilt angles of active regions increase with their latitude (Joy's law). It has never been checked before, however, whether the average tilt angles change from one cycle to the next. Flux transport models show the importance of tilt angles for the reversal and build up of magnetic flux at the poles, which is in turn correlated to the strength of the next cycle. Aims: Here we analyse time series of tilt angle measurements and look for a possible relationship of the tilt angles with other solar cycle parameters, in order to glean information on the solar dynamo and to estimate their potential for predicting solar activity. Methods: We employed tilt angle data from Mount Wilson and Kodaikanal observatories covering solar cycles 15 to 21. We analyse the latitudinal distribution of the tilt angles (Joy's law), their variation from cycle to cycle, and their relationship to other solar cycle parameters, such as the strength (or total area covered by sunspots in a cycle), amplitude, and length. Results: The two main results of our analysis follow. 1. We find an anti-correlation between the mean normalised tilt angle of a given cycle and the strength (or amplitude) of that cycle, with a correlation coefficient of rc = -0.95 (99.9% confidence level) and rc = -0.93 (99.76% confidence level) for Mount Wilson and Kodaikanal data, respectively. 2. The product of the cycle's averaged tilt angle and the strength of the same cycle displays a significant correlation with the strength of the next cycle (rc = 0.65 at 89% confidence level and rc = 0.70 at 92% confidence level for Mount Wilson and Kodaikanal data, respectively). An even better correlation is obtained between the source term of the poloidal flux in Babcock-Leighton-type dynamos (which contains the tilt angle) and the amplitude of the next cycle. Further we confirm the linear relationship (Joy's law) between the tilt angle and latitude with slopes of 0.26 and 0.28 for Mount Wilson and Kodaikanal data, respectively. In addition, we obtain good positive correlations between the normalised-area-weighted tilt angle and the length of the following cycle, whereas the strength or the amplitude of the next cycle does not appear to be correlated to the tilt angles of the current cycle alone. Conclusions: The results of this study indicate that, in combination with the cycle strength, the active region tilt angles play an important role in building up the polar fields at cycle minimum.

Dasi-Espuig, M.; Solanki, S. K.; Krivova, N. A.; Cameron, R.; Peñuela, T.

2010-07-01

343

Angle-resolved transmission spectroscopy of opal films  

NASA Astrophysics Data System (ADS)

The angular behavior of light transmission through opal films over a broad range of wavelengths and angles was investigated. The opal films were prepared using the capillary deposition method (CDM). Many well-defined diffraction peaks were detected and indicate that the CDM results in opal films with high quality. Peaks coinciding at normal incidence split when samples are rotated. The angular shift of these peaks was found to satisfy the kinematical diffraction theory very well. Furthermore, the variation of intensity with incident angle can be interpreted in terms of a simplified dynamical diffraction theory. Moreover, the presence of two differently oriented domains in CDM-made opal films is essential in discussing the measured spectra.

Muldarisnur, M.; Popa, I.; Marlow, F.

2012-07-01

344

Precision measurement of the weak mixing angle in Moller scattering  

SciTech Connect

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Moeller) scattering: A{sub PV} = (-131 {+-} 14 (stat.) {+-} 10 (syst.)) x 10{sup -9}, leading to the determination of the weak mixing angle sin{sup 2} {theta}{sub W}{sup eff} = 0.2397 {+-} 0.0010 (stat.) {+-} 0.0008 (syst.), evaluated at Q{sup 2} = 0.026 GeV{sup 2}. Combining this result with the measurements of sin{sup 2} {theta}{sub W}{sup eff} at the Z{sup 0} pole, the running of the weak mixing angle is observed with over 6{sigma} significance. The measurement sets constraints on new physics effects at the TeV scale.

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.; /UC, Berkeley /Caltech /Massachusetts U., Amherst /Princeton U. /DAPNIA, Saclay /Smith Coll. /SLAC /Syracuse U. /Jefferson Lab /Virginia U.

2005-05-04

345

Precision Measurement of the Weak Mixing Angle in Moeller Scattering  

SciTech Connect

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Moeller) scattering: A{sub PV}=[-131{+-}14(stat){+-}10(syst)]x10{sup -9}, leading to the determination of the weak mixing angle sin{sup 2}{theta}{sub W}{sup eff}=0.2397{+-}0.0010(stat){+-}0.0008(syst), evaluated at Q{sup 2}=0.026 GeV{sup 2}. Combining this result with the measurements of sin{sup 2}{theta}{sub W}{sup eff} at the Z{sup 0} pole, the running of the weak mixing angle is observed with over 6{sigma} significance. The measurement sets constraints on new physics effects at the TeV scale.

Anthony, P.L.; Bower, G.; Erickson, R.; Fieguth, T.; Field, C.; Keller, L.; Olson, M.; Pitthan, R.; Saxton, O.; Szalata, Z.M.; Turner, J.; Walz, D.; Weber, T.; Weisend, J.; Woods, M. [Stanford Linear Accelerator Center, Menlo Park, California 94025 (United States); Arnold, R.G.; Arroyo, C.; Cahoon, J.; Hicks, R.S.; Kaufman, L.J. [University of Massachusetts, Amherst, Massachusetts 01003 (United States)] [and others

2005-08-19

346

Compact low-power high-sensitivity angle sensor  

NASA Astrophysics Data System (ADS)

We present the design of a compact battery-powered optical angle sensor, together with the first results obtained using the prototype measuring system. The output of the sensor is proportional to cos 2? over a full 360°, where ? is the (possibly static) angle of rotation from a designated zero orientation. Over the more limited range of approximately +/-20° the measured angular sensitivity is in excess of 70 mV/°, corresponding to an angular resolution of +/-0.01°. Although the cos 2? dependency was created in order to meet the requirements of a dynamical quadrupole measuring instrument, this sensor could be useful in applications which require a highly sensitive, yet compact, contactless, measurement of rotation, over (say) +/-20°.

Lockerbie, N. A.; McDonald, N. J.; Weston, R. G.

2004-04-01

347

A novel high resolution ion wide angle spectrometer  

SciTech Connect

A novel ion wide angle spectrometer (iWASP) has been developed, which is capable of measuring angularly resolved energy distributions of protons and a second ion species, such as carbon C{sup 6+}, simultaneously. The energy resolution for protons and carbon ions is better than 10% at {approx}50 MeV/nucleon and thus suitable for the study of novel laser-ion acceleration schemes aiming for ultrahigh particle energies. A wedged magnet design enables an acceptance angle of 30 deg. ({approx}524 mrad) and high angular accuracy in the {mu}rad range. First, results obtained at the LANL Trident laser facility are presented demonstrating high energy and angular resolution of this novel iWASP.

Jung, D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Hoerlein, R. [Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Gautier, D. C.; Letzring, S.; Albright, B. J.; Shah, R.; Palaniyappan, S.; Yin, L.; Fernandez, J. C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Kiefer, D.; Habs, D. [Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Allinger, K. [Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Hegelich, B. M. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany)

2011-04-15

348

Trochlear inclination angles in normal and dysplastic knees.  

PubMed

Trochlear morphology impacts component position in patellofemoral arthroplasty. We devised a measurement of the trochlear inclination angle (TIA) and determined the average TIA in normal and dysplastic knees. Three hundred twenty-nine consecutive magnetic resonance imagings of normal and dysplastic knees were evaluated. The TIA was measured by 2 reviewers. The Student t test was used, and intraobserver reliability measurements were made. The mean TIA in normal and dysplastic knees was internally rotated 11.4° (range, 6°-20°) and 9.4° (range, 4°-15°), respectively. The mean TIA did not differ significantly by sex or age. Trochlear inclination angles in both normal and dysplastic knees tend toward internal rotation. Positioning a trochlear patellofemoral arthroplasty component flush with the articular surface of the native trochlea would result in internal rotation malposition. PMID:22704031

Kamath, Atul F; Slattery, Thomas R; Levack, Ashley E; Wu, Chia H; Kneeland, J Bruce; Lonner, Jess H

2012-06-15

349

XFEL OSCILLATOR SIMULATION INCLUDING ANGLE-DEPENDENT CRYSTAL REFLECTIVITY  

SciTech Connect

The oscillator package within the GINGER FEL simulation code has now been extended to include angle-dependent reflectivity properties of Bragg crystals. Previously, the package was modified to include frequencydependent reflectivity in order to model x-ray FEL oscillators from start-up from shot noise through to saturation. We present a summary of the algorithms used for modeling the crystal reflectivity and radiation propagation outside the undulator, discussing various numerical issues relevant to the domain of high Fresnel number and efficient Hankel transforms. We give some sample XFEL-O simulation results obtained with the angle-dependent reflectivity model, with particular attention directed to the longitudinal and transverse coherence of the radiation output.

Fawley, William; Lindberg, Ryan; Kim, K-J; Shvyd'ko, Yuri

2010-08-23

350

ACS Polarization Calibration - II. The POLV Filter Angles  

NASA Astrophysics Data System (ADS)

During the astrometric calibration of the polarizer filters, it was noticed that residual star positions between polarized and non-polarized images were highly anisotropic, and rotate modulo the 60 degree rotations of the polarizer filters. We speculate that this anisotropy is produced during manufacture of the polaroid material, and use this to derive the E-vector directions of the POLV filter set. The resulting angles are within 0.3 degrees of those expected from the ACS design specifications, except for the POL60V filter which shows a difference of 1.5 degrees. This strongly confirms the POLV filters are mounted in the filter wheel near their expected rotation angles, and confirms our overall understanding of the camera geometry.

Biretta, J.; Kozhurina-Platais, V.

2004-06-01

351

6-DOF displacement and angle measurements using heterodyne laser encoder  

NASA Astrophysics Data System (ADS)

In this research, a novel heterodyne laser encoder for 6-DOF displacement and angle measurements is proposed. The technique combines the advantages of heterodyne interferometry, grating shearing interferometry, and Michelson interferometry. When a heterodyne light beam with two orthogonally polarized directions is used to focus on a semi-transmission grating, two detection configurations for in-plane and out-of-plane will be obtained. By means of measuring the phase variations of the interfering signals from the moving grating, the in-plane displacement can be acquired. Besides, the out-of-plane displacement can be obtained by detecting the optical path difference between the reference beam and the reflection beam. Furthermore, 6-DOF displacement and angle information can be measured simultaneously by using the beam dividing method. According to the experimental results, the measurement resolution is about 2 nm. The experimental results show that our proposed method has the ability to measure 6-DOF displacement and angle information with high system stability. Comparing with other commercial measurement instructions, this laser encoder has the advantages of high resolution, high stability, and high flexibility.

Pan, Ssu-Wen; Hsieh, Hung-Lin; Wang, Wei-Cheng

2013-09-01

352

A new model for the formation of contact angle and contact angle hysteresis  

NASA Astrophysics Data System (ADS)

The formation mechanism of the contact angle and the sliding angle for a liquid drop on a solid surface plays an important role in producing hydrophobic surfaces. A new half soakage model is established in this paper as a substitute for Wenzel (complete soakage) and Cassie (no soakage) models. The model is suited to many solid surfaces, whether they are hydrophilic or hydrophobic, or even superhydrophobic. Based on the half soakage model, we analyse two surfaces resembling lotus, i.e. taper-like surface and corona-like surface. Furthermore, this new model is used to establish a quantitative relationship between the sliding angle and the parameters of surface morphology.

Gong, Mao-Gang; Liu, Yuan-Yue; Xu, Xiao-Liang

2010-10-01

353

Determination of contact angle from the maximum height of enlarged drops on solid surfaces  

NASA Astrophysics Data System (ADS)

Measurement of the liquid/solid contact angle provides useful information on the wetting properties of fluids. In 1870, the German physicist Georg Hermann Quincke (1834-1924) published the functional relation between the maximum height of an enlarged drop and its contact angle. Quincke's relation offered an alternative to the direct measurement of contact angle, which in practice suffers from several experimental uncertainties. In this paper, we review Quincke's original derivation and show that it is based on a hidden assumption. We then present a new derivation that exposes this assumption and clarifies the conditions under which Quincke's relation is valid. To explore Quincke's relation experimentally, we measure the maximum height of enlarged water drops on several substrates and calculate the contact angle in each case. Our results are in good agreement with contact angles measured directly from droplet images.

Behroozi, F.

2012-04-01

354

Monitoring of desert dune topography by multi angle sensors  

NASA Astrophysics Data System (ADS)

Nowadays, the sandy desert is rapidly expanding world widely and results in a lot of risks in the socio-econimical aspects as well as the anthropogenic activities. For example, the increasing occurrences of mineral dust storm which presumably originated from the sandy deserts in northwest China become a serious threat in human activities as well as public health over Far East Asian area as the interpretation by the MODIS analysis (Zhang et al., 2007) and the particle trajectory simulation with HYSPLYT (HYbrid Single-Particle Lagrangian Integrated Trajectory) (Kim et al., 2011) identified. Since the sand dune activity has been recognized as an essential indicator of the progressive desertification, it is important to establish the monitoring method for the variations of topographic properties by the dune activities such as local roughness. Thus it will provide the crucial data about the extent and the transition of sandy desert. For example, it is well known the aerodynamic roughness lengths Zo which can be driven from the specialized sensor such as POLDER (POLarization and Directionality of the Earth's Reflectances) is essential to understand desert dune characteristics. However, for the multi temporal observation of dune fields, the availability of data set to extract Zo is limited. Therefore, we employed MISR (Multi angle imaging Spectro Radiometer) image sequence to extract multi angle topographic parameters such as NDAI (Normalized Difference Angular Index) or the variation of radiance with the viewing geometry which are representing the characteristics of target desert topography instead of Zo. In our approach, NDAI were expanded to the all viewing angles and then compared over the target sandy desert and the surrounding land covers. It showed very strong consistencies according to the land cover type and especially over the dynamic dune fields. On the other hands, the variation of NDAIs of sandy desert combining with the metrological observations were examined and showed a correlation between the intensities sand dune activities and the surface wind conditions. In conclusion, we proved that the trace of the sandy desert boundaries for long observation period is feasible with the multi angle orbital sensor observation by investigating the expanded NDAIs from various sample sand dune fields. However, it is quite uncertain whether the consistency of MISR NDAIs over sandy deserts originated from the aeolian micro structures, the reflectance of sand or the aspect angle of dune morphology. Therefore, in the next stage, the local roughness properties extracted from MISR data analysis will be compared with the topographic information from high resolution stereo satellite imagery such as ALOS PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping). Consequently it will correctly evaluate the suitability of multi angle observation parameters as a dune activity indicator.

Yun, J.; Kim, J.; Choi, Y.; Yun, H.

2011-12-01

355

Development of a MEMS gyroscope for absolute angle measurement  

NASA Astrophysics Data System (ADS)

MEMS gyroscopes are typically designed to measure angular rate of rotation. A measurement of the angle itself is useful in many applications but cannot be obtained by integrating the angular rate due to the presence of bias errors which cause a drift. This thesis presents an innovative design for a vibrating gyroscope that can directly measure both angle and angular rate. The design is based on the principle of measuring the angle of free vibration of a suspended mass with respect to the casing of the device. Several critical challenges have to be handled before the theoretical sensing concept can be converted into a reliable practical sensor. These include compensating for the presence of dissipative forces, mismatched springs, cross-axis stiffness and transmission of rotary torque. These challenges are addressed by the development of a composite nonlinear feedback control system that compensates for each of the above effects and ensures that the mass continues to behave as a freely vibrating structure. Theoretical analysis and simulation results presented in this thesis show that the gyroscope can accurately measure both angle and angular rate for low bandwidth applications. A MEMS device is designed and fabricated to evaluate the real-world experimental performance of the sensor. It utilizes electrostatic comb actuators and capacitive sensing along both vibration axes fabricated by using Deep Reactive Ion Etching (DRIE) technique. Sensor noise is found to be a major impediment to successful implementation of the controller. The use of a Kalman filter enables some mitigation of noise and successful implementation of control, but the Kalman filter gain cannot be selected too high due to system stability limitations. In summary, the developed sensor provides a slightly improved measurement of angle compared to that obtained from integrating a commercially available rate gyroscope. However, due to noisy position measurements, it is unable to provide the drift free performance predicted by theory. Several lines of investigation are suggested in the thesis to study and solve the noise problem associated with the capacitive sensors. Simulations show that reducing the noise in the capacitive sensors will enable significantly superior angle measurement.

Piyabongkarn, Damrongrit

356

Agreement between visual and goniometric assessments of adductor and popliteal angles in infants  

PubMed Central

Context: Amiel-Tison method is a commonly used technique for assessing tone and neurological status of infants. There is a paucity of data on the reliability of visual assessment of angles, a component of this method. Subjects and Methods: We compared the visual and the goniometric assessment of adductor and popliteal angles in infants with hypertonia and neurologically normal controls. A total of 16 infants with hypertonia and 15 normal infants underwent blinded assessment of the adductor and popliteal angles. Statistical Analysis: The mean and standard deviation for the difference between visual and goniometric measurements were calculated for popliteal and adductor angles. Results: The mean differences between visual and goniometric measurements for the popliteal angle were 4.94 (SD3.40) and 8.73 (SD6.10) degrees for the cases and controls respectively. Similarly, the values for adductor angle measurements were 8.94 (SD8.23) and 14.47 (SD8.47) degrees respectively. Conclusion: The deviation of visual assessment from goniometric measurement was found to be less for popliteal angle measurement as compared to adductor angle measurements. It was note-worthy that the difference was less for the measurements of children with spasticity.

Jayakrishnan, Thejus T.; Sharma, Suvasini; Gulati, Sheffali; Pandey, R. M.; Wadhwa, Sanjay; Paul, Vinod K.

2013-01-01

357

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

358

Quantitative genetic analysis and mapping of leaf angle in durum wheat.  

PubMed

The leaf erectness profile has been used to optimize plant architecture since erect leaves can enhance photosynthesis and dry matter production by greater sunlight capture. Brassinosteroid is a recent class of phytohormones that has been related to a more erect profile. There are no reports in the literature of the genetic variability of leaf angle in doubled haploid durum wheat populations; most studies on leaf angle have focused on the inheritance. Our aim was to study the genetic variation in flag and penultimate leaf angle in a durum wheat doubled haploid mapping population, identifying and mapping quantitative trait loci influencing leaf angle. An F(1)-derived doubled haploid population of 89 lines from the cross Strongfield/Blackbird was used to construct a genetic map using 423 molecular marker loci. Two greenhouse experiments and one field test were conducted using an alpha lattice in a randomized complete block design with three replicates. The leaf angle was measured on flag and penultimate leaf with a protractor at three different growth stages. The results indicated poor to moderate correlations between the position of the leaf angle and the growth stage. Transgressive segregation beyond Strongfield and Blackbird of leaf angle was observed for all environments. Putative trait loci were identified on chromosomes 2A, 2B, 3A, 3B, 4B, 5B and 7A. This work helps to understand the genetics of leaf angle in durum wheat. PMID:22868576

Isidro, Julio; Knox, Ron; Clarke, Fran; Singh, Asheesh; DePauw, Ron; Clarke, John; Somers, Daryl

2012-08-07

359

Kinematics of Gait: New Method for Angle Estimation Based on Accelerometers  

PubMed Central

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).

Djuric-Jovicic, Milica D.; Jovicic, Nenad S.; Popovic, Dejan B.

2011-01-01

360

Agreement Between Panoramic and Lateral Cephalometric Radiographs for Measuring the Gonial Angle  

PubMed Central

Background The gonial angle is one of the most important measurements required for orthodontic treatment and orthognathic surgery. It is difficult to determine the accurate measurement of each gonial angle on cephalometric radiographs because of superimposition of the left and right angles. Objectives The aim of the present study was to determine the right and left gonial angles on panoramic radiographs and to compare them with an evaluated cephalometric sample. Patients and Methods A total of 80 panoramic and 80 cephalometric radiographs were obtained from 6 to 12-year-old children and the gonial angle was determined by the tangent of the inferior border of the mandible and the most distal aspect of the ascending ramus and the condyleon both panoramic and cephalometric radiographs. We used Pearson’s correlation coefficient and paired t-test for comparison. Results The mean gonial angle was 127.07 ± 6.10 and 127.5 ± 6.67 degrees on panoramic and cephalometric radiographs, respectively. There was no statistically significant difference between the measured gonial angles on panoramic and cephalometric radiographs and also no difference between the right and left (both Ps = 0.18) Conclusion The value of the gonial angle measured on panoramic radiography was the same as that measured on the routinely used cephalometric radiography.

Zangouei-Booshehri, Maryam; Aghili, Hossein-Agha; Abasi, Mojtaba; Ezoddini-Ardakani, Fatemeh

2012-01-01

361

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.

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

2012-01-01

362

Spherical sector model for describing the experimental small-angle neutron scattering data for dendrimers  

SciTech Connect

A new model for interpreting the results of small-angle neutron scattering from dendrimer solutions is proposed. The mathematical description is given and the theoretical small-angle scattering curves for spherical sectors with different parameters are presented. It is shown that the model proposed is in good agreement with the experimental results. Comparison of the experimental small-angle neutron scattering curves for polyallylcarbosilane dendrimers of the ninth generation with model scattering curves suggests that the inner dendrimer sphere is permeable to a solvent whose density is lower than the density of the solvent beyond the dendrimer by a factor of at least 2.

Rogachev, A. V.; Cherny, A. Yu. [Joint Institute for Nuclear Research (Russian Federation); Ozerin, A. N. [Russian Academy of Sciences, Institute of Synthetic Polymer Materials (Russian Federation); Gordeliy, V. I.; Kuklin, A. I. [Joint Institute for Nuclear Research (Russian Federation)], E-mail: kuklin@nf.jinr.ru

2007-05-15

363

An approach to standing phase angle reduction  

SciTech Connect

This paper is part of a series presented on behalf of the System Restoration Subcommittee with the intent of focusing industry attention on power system restoration. The presence of excessive standing phase angle (SPA) differences across open circuit breakers causes significant delays in power system restoration. These angles may occur across a tie line between two systems or between two connected subsystems within a system. They must be within SPA limits before an attempt is made to close breakers to firm up the bulk power transmission system. There has been a need for an efficient methodology to serve as a guideline for reducing excessive SPA differences to allowable limits, without resorting to the raising and lowering of various generation levels on a trial and error basis. This paper describes such a methodology.

Wunderlich, S.; Fischl, R.; Nwankpa, C.O. (Drexel Univ., Philadelphia, PA (United States)); Adibi, M.M. (IRD Corp., Bethesda, MD (United States))

1994-02-01

364

Riser angle control apparatus and method  

SciTech Connect

A riser angle control apparatus and method is described for use with a floating vessel having well drilling equipment, including an elongated riser having upper elements connected to the floating vessel by vessel connection means, and first flexible coupling means located adjacent the vessel connection means, the riser extending down from the vessel connection means to a point adjacent the ocean floor. The improvement described here consists of riser angle control apparatus comprising: second flexible coupling means operatively engaged with a portion of the upper elements of the riser below the first flexible coupling means, liquid phase of the pumpable waste or increase the specific gravity thereof; and adsorbents, in order to minimize convergence of the salt cavern by narrowing the difference between the specific gravity of the salt cavern walls and the specific gravity of the liquid phase of the pumpable waste by converting the liquid phase to a paste-like or solid consistency.

Dension, E.B.

1986-03-18

365

Invariant-angle coherent states for the singular oscillator and geometrical phases and angles  

SciTech Connect

Exact coherent states describing the invariant-angle variables for the time-dependent singular oscillator are constructed. Through the use of these coherent states we show how to derive the nonadiabatic Hannay{close_quote}s angle from nonadiabatic Berry{close_quote}s phase and also we get the exact classical evolution from the quantum evolution for the time dependent singular oscillator. {copyright} 1997 Academic Press, Inc.

Maamache, M. [Institut de Physique, Universite de Setif, Setif (19000) (Algeria)

1997-02-01

366

Fast right-angle spinning EPR on organic radicals: Resolution enhancement and angle determination  

Microsoft Academic Search

Fast right-angle sample spinning (RAS) with rotation frequencies up to 17 kHz at temperatures down to 205 K is applied to\\u000a electron paramagnetic resonance (EPR) experiments on organic radicals. Echo-detected RAS EPR provides substantial resolution\\u000a enhancements for the range of anisotropies between 10 and 100 MHz which is not accessible with either magic-angle sample spinning\\u000a EPR or anisotropy-resolved EPR on

D. Hessinger; C. Bauer; G. Jeschke; H. W. Spiess

2001-01-01

367

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

Microsoft Academic Search

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

J. E. Allnutt

1977-01-01

368

Wide-Angle Metal-Plate Optics  

Microsoft Academic Search

The design equations for constrained metal-plate lenses are derived. These lenses prove to have exceptional wide-angle scanning properties. The scanning aberrations are investigated by means of a power series expansion of the phase error. This analysis indicates that the square-law error is a function of lens depth and may be eliminated by the proper choice of lens thickness. It is

J. Ruze

1950-01-01

369

Ultra small angle scattering versus diffraction  

NASA Astrophysics Data System (ADS)

In the case of ultra small angle (neutron or x-ray) scattering (USANS, USAXS) it may happen that structures under investigations are not fully coherently illuminated by the incident wave. Despite this fact interference effects are observed similar to SAS data. In this case the measured scattering patterns must be different interpreted. We propose a procedure to calculate and adapt such scattering patterns to experimental data.

Ebrahimi, O.; Treimer, W.; Strobl, M.; Feye-Treimer, U.; Beul, N.; Jericha, E.; Seidel, S. O.

2010-11-01

370

Isolated osteochondroma near the mandibular angle.  

PubMed

A benign tumour of osseous and cartilaginous origins, osteochondroma generally develops in osseous tissue and is frequently found near the end of long bones. It is relatively rare in the oral and maxillofacial region but is common in the mandibular condyle and coronoid process in the pediculate form. This is a report on a rare case of osteochondroma in soft tissue near the mandibular angle without pedicle to the bone. PMID:17052896

Sakai, H; Minemura, T; Ito, N; Miyazawa, H; Kurashina, K

2006-10-18

371

Specificity of joint angle in isometric training  

Microsoft Academic Search

Summary  Six healthy women (21.8±0.4 y) did isometric strength training of the left plantarflexors at an ankle joint angle of 90°. Training sessions, done 3 times per week for 6 weeks, consisted of 2 sets of ten 5 s maximal voluntary contractions. Prior to and following the training, and in random order, voluntary and evoked isometric contraction strength was measured at

T. A. Kitai; D. G. Sale

1989-01-01

372

Measurement of the angle alpha at BABAR  

SciTech Connect

The authors present recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory, operating at the {Upsilon}(4S) resonance. They present constraints on {alpha} from B {yields} {pi}{pi}, B {yields} {rho}{rho} and B {yields} {rho}{pi} decays.

Perez, A.; /Orsay, LAL

2009-06-25

373

Elastic impedance variation with angle inversion for elastic parameters  

NASA Astrophysics Data System (ADS)

Elastic impedance (EI) and amplitude variation with offset or angle (AVO/AVA) inversion are two cardinal methods to estimate elastic parameters underground with reflection seismic data. Conventional EI inversion as a kind of pre-stack and post-stack joint inversion method has been widely applied in the industry because of its high efficiency and high stability of wavelet extraction; however, the robustness of extracting elastic parameters in conventional EI inversion is still controversial. The robustness of three-term AVO inversion has improved a lot; however, it is still challenging to extract reasonable space variant wavelets for each offset or incident angle. In this paper, a robust three-parameter estimation method, named elastic impedance variation with angle (EVA) inversion, is proposed in the Bayesian framework, which can estimate elastic parameters directly from EI. This method supposes that the parameters to be inverted are Cauchy distributed and it is implemented based on a normalized EI equation in a logarithmic domain which can reduce the nonlinearity of inversion. Application of a covariance matrix to decorrelate the parameters and constraint of well log curves introduced in an objective function enhances the robustness of EVA inversion. A model test shows that the proposed EVA inversion method enables one to estimate reasonable elastic parameters with extremely smooth initial models and moderate Gaussian noise. A real data example shows that the inverted P-wave velocity, S-wave velocity and density are identical to well log interpretation results, which shows the validity of the proposed method.

Zong, Zhaoyun; Yin, Xingyao; Wu, Guochen

2012-06-01

374

Role of fiber functionality and angle on cell migration.  

NASA Astrophysics Data System (ADS)

In order to determine the role of surface interactions on cell migration we compared the cell velocity on electrospun PMMA fibers which were either etched with UV/ozone plasma, had pre-adsorbed Fibronectin or both. It shows that dermal fibroblasts (CF-29, ATCC) did not adhere to the fibers without treatment, and the migration of cells was fastest on with both etching and pre-coat FN fibers. Vinculin was used to stain for the focal adhesion points and the largest number per cell were found on the FN pre-incubated samples, and nearly none on the plasma etched surface, despite good proliferation and migration. The results indicate that the migration velocity need not directly correlate to the cell adhesion. Using FN coated fibers we also studied the effect of angle on crossed fibers. We found that there was a clear preference by the cells for crossing a matrix where the fibers were oriented at 30 degrees. At this angle the migration velocity was slowest. Movies of the migrating cells indicate that the residence time of the cells at junctions with this angle is the longest cut to the interactions of the motion between fibers. The largest speed was observed for fibers placed at 90 degree.

Qin, Sisi; Clark, Richard; Rafailovich, Miriam

2012-02-01

375

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

376

Directional adhesion of gecko-inspired angled microfiber arrays  

NASA Astrophysics Data System (ADS)

Arrays of angled microfibers with a gecko-inspired structure were fabricated from a stiff thermoplastic polymer (polypropylene) with elastic properties similar to those of ?-keratin of natural setae. Friction experiments demonstrated that this fibrillar polymer surface exhibits directional adhesion. Sliding of clean glass surfaces against and along the microfiber direction without applying an external normal force produced an apparent shear stress of 0.1 and 4.5 N/cm2, respectively. This directional adhesion is interpreted in the context of a nonlinear elastic bending model of an angled beam. Shearing and normal contact experiments yielded further evidence of the anisotropic adhesion of the fibrillar polymer and revealed the occurrence of a pull-off (adhesive) force at the instant of surface detachment, unlike vertically aligned microfiber arrays of the same material that exhibited a zero pull-off force. The results of this study provide impetus for the design of gecko-inspired adhesives with angled structures that demonstrate directional adhesion against different material surfaces.

Lee, Jongho; Fearing, Ronald S.; Komvopoulos, Kyriakos

2008-11-01

377

Orbit Propagation Strategies with Angle-Only Observations  

NASA Astrophysics Data System (ADS)

Precise orbit determination and prediction plays an increasingly important role the more dense the population of resident space objects becomes. In this paper different strategies are dis-cussed how to propagate an orbit with angle-only observations. Different orbital regimes are investigated as well as the influence of the temporal spacing of observations. The focus is on objects which do not perform manoeuvres to clearly separate the effects of, probably unavail-able and/or inaccurate, manoeuvre data from modeling the natural forces. Orbit determination and propagation is performed with an enhanced version of the CelMech tool (Beutler, Meth-ods of Celestrical Mechanics, Springer 2001). The ephemerides of the propagated orbits are compared to observations of the same object, which were not used for orbit determination. These additional angle-only observations serve as a ground truth. The data is analyzed with respect to predicted and actually observed covariances. As a reference two line element data (TLEs) of the US Strategic Command (USSTRATCOM) catalogue are propagated with the SDP4 propagator and the resulting ephemerides are compared to the angle-only observations.

Früh, Carolin; Schildknecht, Thomas

378

Influence of substrate temperature on glancing angle deposited Ag nanorods  

SciTech Connect

When Ag sculptured thin films were grown with glancing angle deposition by ion beam sputtering at either room temperature or elevated substrate temperatures T{sub S}, a large morphological difference was observed. The incident particle flux reached the silicon substrate at a glancing angle {beta}{>=}80 deg. as measured to the substrate normal. A slit aperture was used in order to reduce the particle beam divergence. At room temperature, columnar structures were formed, irrespective of the presence of the slit aperture. At elevated temperatures (573 and 623 K) and collimated particle flux in the presence of the slit aperture, however, enhanced surface diffusion causes the growth of crystalline nanorod- and nanowirelike structures. In the absence of the slit aperture, the flux beam divergence is higher, resulting in island- and mountainlike crystalline structures. The density of the nanorods and nanowires was observed to be higher on the planar Si substrates in comparison to honeycomblike prepatterned substrates with different pattern periods. On the patterned substrates, the nanorods are not necessarily found to be evolving on the seed points but can rather be also observed in-between the artificial seeds. The glancing angle deposited films at high temperatures were observed to be polycrystalline, where the (111) crystal orientation of the film is dominant, while the presence of the less intense (200) reflection was noticed from the x-ray diffraction measurements. In contrast, compact thin films deposited with {beta}{approx_equal}0 deg. at high temperatures were found to be epitaxial with (200) orientation.

Khare, C.; Patzig, C.; Gerlach, J. W.; Rauschenbach, B.; Fuhrmann, B. [Leibniz Institute of Surface Modification, Permoserstrasse 15, 04318 Leipzig (Germany); Interdisciplinary Centre of Materials Science, Martin-Luther-University Halle, Heinrich-Damerow-Strasse 4, 06120 Halle (Germany)

2010-07-15

379

Comparison of glancing angle EXAFS extracted from reflectivity and fluorescence modes  

SciTech Connect

EXAFS extracted from glancing angle fluorescence and reflectivity data are compared after correcting for the anomalous dispersion distortions. Preliminary results show good agreement in the information obtained from the two techniques. 3 refs., 1 fig.

Chen, H.; Heald, S.M.

1988-01-01

380

Carbon Fiber Morphology, II: Expanded Wide-Angle X-Ray Diffraction Studies of Carbon Fibers.  

National Technical Information Service (NTIS)

This report, describes the wide-angle x-ray diffraction studies and results on carbon and graphite fibers. Commercial PAN- and pitch-based carbon fibers spanning the generally available modulus range were examined. Crystal perfection, size, orientation, a...

D. P. Anderson

1991-01-01

381

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

382

Peripapillary atrophy in primary angle-closure glaucoma: a comparative study with primary open-angle glaucoma  

Microsoft Academic Search

PURPOSE: To investigate the characteristics of peripapillary atrophy in primary angle-closure glaucoma and to compare peripapillary atrophy in primary angle-closure glaucoma with that in primary open-angle glaucoma.METHODS: Twenty-one eyes (of 21 patients) with chronic primary angle-closure glaucoma that had no evidence of an acute attack or combined-mechanism glaucoma and 31 eyes (31 patients) with primary open-angle glaucoma were enrolled in

Hideya Uchida; Tetsuya Yamamoto; Goji Tomita; Yoshiaki Kitazawa

1999-01-01

383

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

384

Design of a MOEMS-based electromagnetic driven high efficacious phase grating with angle sensor  

NASA Astrophysics Data System (ADS)

A novel design for fabricating the high efficacious rectangular phase grating with angle sensor by MOEMS fabrication process is presented in this paper. The purpose of this design is for increasing the Signal-to-Noise of output signal and reducing the size of near infrared spectrometer by using MOEMS grating. Diffraction efficiency is designed and optimizing at first. We used Fourier optical theory and diffraction optical theory analyzed the diffraction efficiency of the rectangular phase grating, and used the PCgrate simulated the design. After analysis and calculation, we found the best parameter of this grating. According the former design of infrared spectrometer by ZEMAX, the angle resolution of angle sensor is 60mV/°, maximal angle is +/-4.7° and the size of grating is 5x6mm2. Because of the large deflection angle, the electromagnetic force is used for driving this grating. For sensing the grating deflexion angle, we design the angle sensor in the torsion bar of this grating. This sensor is P-type piezoresistive sensor and fabricated on n-(100) high-resistance silicon wafer by boron ion implantation. Analyses stress of torsion bar and piezoresistive angle sensor with Wheatstone bridge theory, the scanning angle ? in a linear relation with output voltages (Vout) of Wheatstone bridge. The size of torsion bar is 2100?mx220?mx75?m, the frequency of first step model is 550Hz. The size of the sensor is 100?mx15?mx0.5?m. Finally, the compatible fabrication process of this device is given. The results of experiments and theory analyzing demonstrate that MOEMS phase grating could work effectively, and angle sensor achieve the real time need. This MOEMS grating is suitable for infrared spectrometer.

Luo, Biao; Wen, Zhi Yu; Chen, Li

2011-06-01

385

Thermal buckling of thick antisymmetric angle-ply laminates  

SciTech Connect

The buckling behavior of moderately thick antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise is analyzed. Transverse shear deformation is accounted for by employing the thermoelastic version of the Reissner-Mindlin theory. Results for the classical thin-plate theory are obtained as a special case. Numerical results are presented for fiber-reinforced laminates and show the effects of ply orientation, number of layers, plate thickness, and aspect ratio on the critical buckling temperature. Finally, an optimization procedure is proposed for the design of laminates having maximum resistance to thermal buckling. 17 references.

Tauchert, T.R.

1987-01-01

386

Enhancement on Propulsion Performance:. Modifying Angle of Attack Profile  

NASA Astrophysics Data System (ADS)

In this paper, numerical investigation was conducted for an oscillating NACA0012 foil combining the pitching and plunging motions. The plunging follows a sinusoidal motion while the pitching trajectory is controlled by achieving the resultant effective angle of attack (AOA) to be a harmonic cosine form. Computations were conducted over a range of the Strouhal number (St), different maximum effective AOA and different phase difference between pitching and plunging (?). Results show that, at higher St, significant improvement on propulsion performance has been achieved when the effective AOA profile maintains a harmonic cosine form by controlling the pitching motion of the foil.

Xiao, Qing; Liao, Wei; Dou, Hua-Shu

387

Study of critical ricochet angle for conical nose shape projectiles  

NASA Astrophysics Data System (ADS)

The purpose of this research is to formulate a generic analytical model to assess the phenomena of water ricochet for a conical nose shaped projectile. A theoretical model is analyzed to study the critical angle of conical nose shaped projectile entering in water and is extended for different mediums as normal sand and mercury. Numerical Simulation has been carried out to find the effect of tip angle of the conical nose shaped projectile on the critical angle. Critical angle is defined as that angle of impact of the projectile above which ricochet will occur. This angle is obtained by balancing the momentums acting on the projectile at the time of impact on the basis of Newtonian theory. Major factors affecting critical angle are impact velocity, impact angle, density of the projectile and the target. An attempt has been made to study the effect of longitudinal spin of the projectile on the critical angle.

Murali, Vijayalakshmi; Law, Manish G.; Naik, Smita D.

2012-09-01

388

Broadband and wide-angle distributed Bragg reflectors based on amorphous germanium films by glancing angle deposition.  

PubMed

We fabricated the distributed Bragg reflectors (DBRs) with amorphous germanium (a-Ge) films consisted of the same materials at a center wavelength (?c) of 1.33 ?m by the glancing angle deposition. Their optical reflectance properties were investigated in the infrared wavelength region of 1-1.9 ?m at incident light angles (? inc) of 8-70°, together with the theoretical analysis using a rigorous coupled-wave analysis simulation. The two alternating a-Ge films at the incident vapor flux angles of 0 and 75° were formed as the high and low refractive index materials, respectively. The a-Ge DBR with only 5 periods exhibited a normalized stop bandwidth (??/? c) of ~24.1%, maintaining high reflectance (R) values of > 99%. Even at a high ? inc of 70°, the ??/? c was ~21.9%, maintaining R values of > 85%. The a-Ge DBR with good uniformity was obtained over the area of a 2 inch Si wafer. The calculated reflectance results showed a similar tendency to the measured data. PMID:23037105

Leem, Jung Woo; Yu, Jae Su

2012-08-27

389

Applicability of Washburn capillary rise for determining contact angles of powders/porous materials.  

PubMed

The Washburn capillary rise (WCR) technique has been widely utilized for determining contact angles of powders or porous materials; however, there are concerns regarding powder size and powder packing, especially for materials that exhibit large contact angle hysteresis. In this paper, some of these concerns were addressed. Due to the large water contact angle hysteresis on flat nylon 6/6 films, these films were ground into powders of different sizes and then used as model packing materials. The powders were packed in glass tubes to result in various packing structures that affected the penetration (i.e. advancing) rate of the test liquids. While all advancing contact angles obtained from WCR were found to be overestimated, more reasonable values were resulted when relatively large powders (e.g. 500-2000 ?m) were used to pack the tubes. With larger powders, the packing contained bigger voids and consequently lead to slower penetration rates of the liquids, hence a relatively smaller advancing contact angle. The smaller advancing contact angle obtained from the slower advancing rate was also observed by using the sessile drop method. To verify the applicability of using large powders (500-2000 ?m) for contact angle determination by using WCR, the advancing water contact angles of a bacterial cellulose/alginate composite sponge (BCA) with and without UV/ozone treatment were measured. The results showed that by using relatively large powders, WCR could be applied to obtain a reasonable advancing contact angle and assess the wettability change of complex porous materials. PMID:23484765

Kirdponpattara, Suchata; Phisalaphong, Muenduen; Newby, Bi-min Zhang

2013-01-29

390

Bisector angle estimation in a nonsymmetric multipath radar scenario  

NASA Astrophysics Data System (ADS)

This study presents a simple closed-form bisector angle estimator developed on the basis of characteristic features of the 3 x 3 forward-backward averaged beamspace correlation matrix when the center pointing angle is the true bisector angle. The 2D parameter estimation is thus decomposed into two successive 1D parameter estimation problems: estimation of the bisector angle, followed by estimation of the target bearing. Simulations are presented assessing the performance of the new bisector angle estimator and comparing the performance of the symmetric beamspace domain maximum likelihood employing the new estimator with other maximum-likelihood-based bearing estimation schemes in a simulated low-angle radar tracking environment.

Zoltowski, M. D.; Lee, T.-S.

1991-12-01

391

The Aeronomy of Ice in the Mesosphere Mission: Overview and Early Results  

NASA Astrophysics Data System (ADS)

The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 1:26:03 PDT on April 25, 2007 becoming the first satellite mission dedicated to the study of noctilucent clouds. A Pegasus XL rocket launched the satellite into a near perfect 600 km sun synchronous circular orbit. AIM carries three instruments - a nadir imager, a solar occultation instrument and in-situ cosmic dust detectors - that were specifically selected because of their ability to provide key measurements needed to address the six AIM science objectives. Brief descriptions of the science, instruments and observation scenario will be presented along with early science results.

Russell, J. M.; Bailey, S. M.; Thomas, G.; Rusch, D.; Gordley, L. L.; Hervig, M.; Horanyi, M.; Randall, C.; McClintock, W.; Siskind, D. E.; Stevens, M.; Englert, C.; Taylor, M.; Summeers, M.; Merkel, A.

2007-12-01

392

Angle closure glaucoma complicating systemic atropine use in the cardiac catheterization laboratory.  

PubMed

Atropine may precipitate angle closure glaucoma in those predisposed to the disorder. Previously reported cases demonstrate the frequent misdiagnosis of acute glaucoma as conjunctivitis. Resultant delays in treatment can lead to vision loss. The present case describes a 66-yr-old man who developed acute angle closure glaucoma after receiving atropine during a coronary angioplasty produce. Clinicians who utilize atropine should be aware of the possibility of precipitating angle closure glaucoma and the predisposing factors, signs, and symptoms to facilitate prompt diagnosis and treatment of this disorder. PMID:8933969

Mandak, J S; Minerva, P; Wilson, T W; Smith, E K

1996-11-01

393

Direct measurement of the skew angle of the Poynting vector in a helically phased beam.  

PubMed

We measure the local skew angle of the Poynting vector within a helically-phased, exp (il phi), beam using a Shack Hartmann wavefront sensor. It is the skew angle of the Poynting vector with respect to the beam axis that gives rise to the orbital angular momentum of a light beam. We confirm that this skew angle is l/kr, corresponding to an orbital angular momentum of l? per photon. Measurement of orbital angular momentum in this way is an alternative to interferometric techniques giving a non-ambiguous result to both the magnitude and sign of l from a single measurement, without any restriction on the optical bandwidth. PMID:19529616

Leach, Jonathan; Keen, Stephen; Padgett, Miles J; Saunter, Christopher; Love, Gordon D

2006-12-11

394

Kinetic excitation of solids induced by energetic particle bombardment: Influence of impact angle  

NASA Astrophysics Data System (ADS)

The kinetic excitation of a solid surface under bombardment with energetic particles is studied via internal electron emission in a metal-insulator-metal junction. In particular, the dependence of the measured tunneling yield on the projectile impact angle is studied. The resulting impact angle distribution is compared with predictions of the total excitation energy profile calculated using the SRIM 2006 Monte Carlo program package. While the calculated profiles fail to explain the experimental data, it is shown that a simple calculation of impact angle dependent projectile backscattering qualitatively reproduces the observed trends.

Heuser, Christian; Marpe, Mario; Diesing, Detlef; Wucher, Andreas

2009-02-01

395

Central retinal artery and vein collapse pressure in eyes with chronic open angle glaucoma  

PubMed Central

Aims: To determine central retinal vessel collapse pressure in chronic open angle glaucoma. Methods: For 19 eyes with chronic open angle glaucoma and 27 eyes of a control group, central retinal vessel collapse pressure was measured by a Goldmann contact lens fitted with a pressure sensor in its holding grip. Results: Central retinal vein collapse pressure was significantly (p=0.001) higher in the glaucoma group than in the control group (26.1 (SD 26.4) relative units versus 6.1 (8.4) relative units). Conclusions: Measured by a new ophthalmodynamometer, central retinal vein collapse pressure measurements may be abnormally high in eyes with chronic open angle glaucoma.

Jonas, J B

2003-01-01

396

{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); Glatzel, U. [Friedrich-Schiller-Univ. Jena (Germany). Metallische Werkstoffe

1998-12-04

397

Simple map in action-angle coordinates  

NASA Astrophysics Data System (ADS)

A simple map [A. Punjabi, A. Verma, and A. Boozer, Phys. Rev. Lett. 69, 3322 (1992)] is the simplest map that has the topology of divertor tokamaks [A. Punjabi, H. Ali, T. Evans, and A. Boozer, Phys. Lett. A 364, 140 (2007)]. Here, action-angle coordinates, the safety factor, and the equilibrium generating function for the simple map are calculated analytically. The simple map in action-angle coordinates is derived from canonical transformations. This map cannot be integrated across the separatrix surface because of the singularity in the safety factor there. The stochastic broadening of the ideal separatrix surface in action-angle representation is calculated by adding a perturbation to the simple map equilibrium generating function. This perturbation represents the spatial noise and field errors typical of the DIII-D [J. L. Luxon and L. E. Davis, Fusion Technol. 8, 441 (1985)] tokamak. The stationary Fourier modes of the perturbation have poloidal and toroidal mode numbers (m,n,)={(3,1),(4,1),(6,2),(7,2),(8,2),(9,3),(10,3),(11,3)} with amplitude ?=0.8×10-5. Near the X-point, about 0.12% of toroidal magnetic flux inside the separatrix, and about 0.06% of the poloidal flux inside the separatrix is lost. When the distance from the O-point to the X-point is 1 m, the width of stochastic layer near the X-point is about 1.4 cm. The average value of the action on the last good surface is 0.19072 compared to the action value of 3/5? on the separatrix. The average width of stochastic layer in action coordinate is 2.7×10-4, while the average area of the stochastic layer in action-angle phase space is 1.69017×10-3. On average, about 0.14% of action or toroidal flux inside the ideal separatrix is lost due to broadening. Roughly five times more toroidal flux is lost in the simple map than in DIII-D for the same perturbation [A. Punjabi, H. Ali, A. Boozer, and T. Evans, Bull. Amer. Phys. Soc. 52, 124 (2007)].

Kerwin, Olivia; Punjabi, Alkesh; Ali, Halima

2008-07-01

398

On the origin of contact angle hysteresis  

NASA Astrophysics Data System (ADS)

In this study, we consider a simple distribution of defects on a substrate, or a sinusoidal surface, and show explicitly how the pinning and depinning occur for a two dimensional liquid drop on such non-ideal surfaces as the volume of the drop is increased or decreased. We show that the contact angle hysteresis (CAH) emerges from this simple model even though we do not take any effect of viscous dissipation into account, which is in contrast with the conventional theory where the CAH originates from the viscous dissipation inside the liquid around the contact line just after depinning.

Yoshitaki, Yumiko; Okumura, Ko

2009-11-01

399

Anisotropic protective coating for brewster angle windows.  

PubMed

We propose what we believe is a new type of dielectric anisotropic coating of arbitrary thickness that can protect Brewster angle windows without degrading their optical quality. Such a coating may be fabricated as a multilayer two-component structure. The parameters of the structure, i.e., the dielectric permittivities of the components and their concentrations, are calculated. For ZnSe windows two examples of anisotropic coatings are presented. The optical quality of the multilayer films does not depend on their precise thickness, which makes them less sensitive to surface damage. PMID:18323898

Surdutovich, G; Vitlina, R; Baranauskas, V

1999-07-01

400

Simple map in action-angle coordinates  

SciTech Connect

A simple map [A. Punjabi, A. Verma, and A. Boozer, Phys. Rev. Lett. 69, 3322 (1992)] is the simplest map that has the topology of divertor tokamaks [A. Punjabi, H. Ali, T. Evans, and A. Boozer, Phys. Lett. A 364, 140 (2007)]. Here, action-angle coordinates, the safety factor, and the equilibrium generating function for the simple map are calculated analytically. The simple map in action-angle coordinates is derived from canonical transformations. This map cannot be integrated across the separatrix surface because of the singularity in the safety factor there. The stochastic broadening of the ideal separatrix surface in action-angle representation is calculated by adding a perturbation to the simple map equilibrium generating function. This perturbation represents the spatial noise and field errors typical of the DIII-D [J. L. Luxon and L. E. Davis, Fusion Technol. 8, 441 (1985)] tokamak. The stationary Fourier modes of the perturbation have poloidal and toroidal mode numbers (m,n,)=((3,1),(4,1),(6,2),(7,2),(8,2),(9,3),(10,3),(11,3)) with amplitude {delta}=0.8x10{sup -5}. Near the X-point, about 0.12% of toroidal magnetic flux inside the separatrix, and about 0.06% of the poloidal flux inside the separatrix is lost. When the distance from the O-point to the X-point is 1 m, the width of stochastic layer near the X-point is about 1.4 cm. The average value of the action on the last good surface is 0.19072 compared to the action value of 3/5{pi} on the separatrix. The average width of stochastic layer in action coordinate is 2.7x10{sup -4}, while the average area of the stochastic layer in action-angle phase space is 1.69017x10{sup -3}. On average, about 0.14% of action or toroidal flux inside the ideal separatrix is lost due to broadening. Roughly five times more toroidal flux is lost in the simple map than in DIII-D for the same perturbation [A. Punjabi, H. Ali, A. Boozer, and T. Evans, Bull. Amer. Phys. Soc. 52, 124 (2007)].

Kerwin, Olivia; Punjabi, Alkesh; Ali, Halima [Center for Fusion Research and Training, Hampton University, Hampton, Virginia 23668 (United States)

2008-07-15

401

Photonic crystals with glancing angle deposition  

NASA Astrophysics Data System (ADS)

We report a study on thin silicon films fabricated with glancing angle deposition (GLAD). Morphology of these films as a function of shadowing and temperature are examined first. Columnar separation in silicon thin films is investigated with scanning electron microscopy (SEM) and Fourier transform analysis. Column spacing increases with increasing substrate tilt (shadowing). Column spacing is small and varies little with temperature in the temperature range 375--670K, then increases substantially at higher temperature. Column tilt angles of these films are close to the values predicted by Tait's rule. Birefringent properties of bi-deposited silicon films on glass are next examined. In the bi-deposited technique, small quantities of film are deposited successively on a substrate at azimuthal positions of 0, 180; 360, ...degrees. Films are analyzed by spectroscopic ellipsometry in the wavelength range 370--1670nm. These films have three distinct optical indices, and exhibit in-plane birefringence much larger than the naturally occurring birefringent materials such as calcite; or quartz. We show that the birefringence of these films is due to form anisotropy. Plan view SEM images show the presence of column bunching in the film, and subsequent Fourier analysis shows a two-fold symmetry; confirming the directional preference of column density. Square spiral photonic crystals were fabricated with glancing angle deposition. Stop bands at multiple light incident angles indicate a partial gap close to the desired gap frequency of the photonic crystal. Optical indices of these films are determined by anisotropic ellipsometric analysis. Simulation of transmission or reflection spectra for a superlattice of 10 square spiral layers enhances and narrows the transmission drops and reflection peaks in these films at the stop band positions. A square spiral structure was deposited on a Si(100) substrate partially patterned with a square lattice of small bumps. The ellipsometric and reflection spectra for this film within the wavelength range of our instrument do not indicate the presence of a stop band. Scanning electron microscope images of the films seem to indicate that the embedded spacing has been lost. Fourier transform analysis indicates a faint four-fold symmetry in plan view SEM images of all square spiral films.

Beydaghyan, Gisia

402

G.CO Bisecting an 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: Suppose $A$ is an angle with vertex $P$, as pictured below: Draw a circle with center $P$ and with radius $r \\gt 0$. Explain why the circle meets each ...

403

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

404

The planforms of low-angle impact craters in the northern hemisphere of Mars  

NASA Astrophysics Data System (ADS)

We have surveyed Martian impact craters greater than 5 km in diameter using Viking and thermal emission imaging system (THEMIS) imagery to evaluate how the planform of the rim and ejecta changes with decreasing impact angle. We infer the impact angles at which the changes occur by assuming a sin2? dependence for the cumulative fraction of craters forming below angle ?. At impact angles less than ˜40° from horizontal, the ejecta become offset downrange relative to the crater rim. As the impact angle decreases to less than ˜20°, the ejecta begin to concentrate in the crossrange direction and a "forbidden zone" that is void of ejecta develops in the uprange direction. At angles less than ˜10°, a "butterfly" ejecta pattern is generated by the presence of downrange and uprange forbidden zones, and the rim planform becomes elliptical with the major axis oriented along the projectile's direction of travel. The uprange forbidden zone appears as a "V" curving outward from the rim, but the downrange forbidden zone is a straight-edged wedge. Although fresh Martian craters greater than 5 km in diameter have ramparts indicative of surface ejecta flow, the ejecta planforms and the angles at which they occur are very similar to those for lunar craters and laboratory impacts conducted in a dry vacuum. The planforms are different from those for Venusian craters and experimental impacts in a dense atmosphere. We interpret our results to indicate that Martian ejecta are first emplaced predominantly ballistically and then experience modest surface flow.

Herrick, Robert R.; Hessen, Katie K.

2006-10-01

405

Azimuth angle variations of specular reflection echoes in the lower atmosphere observed with the MU radar  

NASA Astrophysics Data System (ADS)

We studied azimuth angle variations of clear-air echoes in the troposphere and lower stratosphere, observed by steering the antenna beam of the MU radar into 12 positions, the azimuth angle being changed every 30° at a zenith angle of 6°. Azimuth angle variations of the echo intensity were recognized in a large height range in the lower stratosphere, although they were also sometimes found in the troposphere, which was approximated by a fairly smooth sinusoidal curve, with one or two cycles in 360° azimuth angle. Moreover, their structure showed continuous progression with time and altitude. The range of variations was generally greater in the lower stratosphere, the ratio of the maximum to the minimum sometimes exceeding 15 dB. The large azimuth angle variations were associated with the aspect sensitivity of the echo power, suggesting that they were caused by the characteristics of specular reflection rather than the effects of localized turbulence scattering, and suggesting that the reflection surface was corrugated, probably the result of the effects of gravity waves. A numerical model qualitatively explained the fundamental behavior of the azimuth angle dependence of the echo power, it being assumed that the vertical displacement of the reflection surface showed sinusoidal variation caused by the dynamical effects of a monochromatic gravity wave.

Tsuda, Toshitaka; Gordon, William E.; Saito, Hideya

1997-05-01

406

Fabrication of surfaces with extremely high contact angle hysteresis from polyelectrolyte multilayer.  

PubMed

High contact angle hysteresis on polyelectrolyte multilayers (PEMs) ion-paired with hydrophobic perfluorooctanoate anions is reported. Both the bilayer number of PEMs and the ionic strength of deposition solutions have significant influence on contact angle hysteresis: higher ionic strength and greater bilayer number cause increased contact angle hysteresis values. The hysteresis values of ~100° were observed on smooth PEMs and pinning of the receding contact line on hydrophilic defects is implicated as the cause of hysteresis. Surface roughness can be used to further tune the contact angle hysteresis on the PEMs. A surface with extremely high contact angle hysteresis of 156° was fabricated when a PEM was deposited on a rough substrate coated with submicrometer scale silica spheres. It was demonstrated that this extremely high value of contact angle hysteresis resulted from the penetration of water into the rough asperities on the substrate. The same substrate hydrophobized by chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane exhibits high advancing contact angle and low hysteresis. PMID:22044032

Wang, Liming; Wei, Jingjing; Su, Zhaohui

2011-11-16

407

Perpendicular Blood Vessel Seals Are Stronger Than Those Made at an Angle  

PubMed Central

Abstract Vessel sealing devices effectively produce hemostatic seals with minimal thermal damage, but the strength of seals decreases as vessel diameter increases. Because vessels sealed at an angle to the vessel require a greater functional seal diameter than those sealed perpendicularly to the vessel, it was hypothesized that perpendicular seals would have comparably higher burst pressures. Ex vivo, porcine carotid arteries of nominal diameters of 5, 6, and 7?mm were sealed perpendicularly to and at a 45° angle to the longitudinal axis of the vessels, and burst pressures of the sealed vessels were measured. Overall burst pressures were 51% greater for perpendicular seals than for angled seals (P<.001). Mean burst pressures for the 5-mm angled and 7-mm perpendicular groups, which have similar seal lengths, were not significantly different (P=.959). Analysis using the functional diameter as a covariate indicated that the seal length is the primary variable in determining burst pressure, and not some other inherent characteristic of angled versus perpendicular sealing. These results suggest that at least for vessels ?5?mm in diameter, surgeons should approach vessels perpendicularly and not at an angle, for the highest possible seal strength. The development of articulated sealing and cutting devices would provide greater seal strength, in addition to improved maneuverability, especially in laparoscopic surgery, where angles of approach may be limited by the fixed location of surface cannulas.

Voegele, Aaron C.; Korvick, Donna L.; Gutierrez, Mario; Amaral, Joseph F.

2013-01-01

408

Bayesian signal detection for multiple aspect targets with an uncertain look angle  

NASA Astrophysics Data System (ADS)

An optimal signal detection theory approach is presented for the determination of the presence or absence of a target observed at multiple aspects in noise, where there is uncertainty in the initial look angle at which the aspects are observed. Potential targets may be interrogated at any number of aspect angles, and receiver operating characteristics (ROCs) are presented as a function of the number of aspects observed. In order to obtain the effect on performance of the number of aspect angles and other characteristics of the signal, ROC comparisons are made for the same total signal-to-noise ratio (SNR), rather than the average SNR per aspect. Target returns from a real multiple aspect target data set, consisting of acoustic backscatter returns from several objects suspended in a tank of water, are utilized in a detection simulation. The result using the real data indicate that, for the same total signal-to-noise ratio, detection does not necessarily improve with an increasing number of look angles. Theoretical analysis shows that optimum detection for this situation occurs when the signals consisting of multiple aspects, but at different initial look angles, are highly correlated. This conclusion is supported by the real data nd shows that detection performance does not necessarily improve with the number of multiple aspect angles observed, for a given total signal- to-noise ratio, when the initial look angle is uncertain.

Rasimas, Jennifer G.; Tantum, Stacy L.; Nolte, Loren W.

1999-08-01

409

Contact angle measurements and interpretation: wetting behavior and solid surface tensions for poly(alkyl methacrylate) polymers  

Microsoft Academic Search

Low-rate dynamic contact angles of a large number of liquids were measured on a poly(ethyl methacrylate) (PEMA) polymer using an automated axisymmetric drop shape analysis profile (ADSA-P). The results suggested that not all experimental contact angles can be used for the interpretation in terms of solid surface tensions: eight liquids yielded non-constant contact angles and\\/or dissolved the polymer on contact.

D. Y. Kwok; A. W. Neumann

2000-01-01

410

A study on structural, optical and hydrophobic properties of oblique angle sputter deposited HfO2 films  

NASA Astrophysics Data System (ADS)

HfO2 thin films have been synthesized by oblique angle reactive DC magnetron sputtering technique. Present study reports the effect of deposition angle on the hydrophobic, structural, surface morphological and optical properties of HfO2 thin films. All the films were deposited at room temperature. HfO2 thin films were found to possess monoclinic crystal structure. Significant changes in topography of the films, with change in deposition angle, have been observed. Surface roughness increases with decrease in deposition angle as observed from AFM image analysis. UV–vis spectroscopy has been used to study the optical properties of the films. Small changes in transmission and refractive index have been observed. The films are hydrophobic in nature and the contact angle is strongly influenced by deposition angle due to change in its surface roughness. Contact angle of 106.3° has been achieved for deposition angle of 30° which is highest so far for HfO2 thin films prepared by magnetron sputtering. The results of this study reflect that contact angle of the films can be tuned by deposition angle. Good optical transmission along with hydrophobic character make HfO2 thin films of great use as optical coatings for lenses, windshields and optoelectronic devices.

Jain, Ravish K.; Gautam, Yogendra K.; Dave, Vikramaditya; Chawla, Amit K.; Chandra, Ramesh

2013-10-01

411

Gated cardiac scanning using limited-angle image reconstruction technique and information in the neighboring phases  

SciTech Connect

It is known that there are gaps in scan angle in gated cardiac scanning due to lack of synchronization between heart beat and CT machine rotation. The missing projections in these gaps result in artifacts in the reconstructed images. In a previous paper an iterative limited-angle reconstruction technique was employed to fill in the missing projections to remove the artifacts. It was found there that the root-mean-square errors of the limited-angle images were reduced to a level comparable to those of reconstructions using complete-angle information. In the present paper the results are further improved by using the scans of a neighboring portion of the cardiac cycle as a first estimate of the missing scans in the phase of interest when initializing the iterations. Such a modification provides a better starting point for the iterations.

Tam, K.C.; MacDonald, B.; Perez-Mendez, V.

1984-02-01

412

Effects of triggering mechanism on snow avalanche slope angles and slab depths from field data  

NASA Astrophysics Data System (ADS)

Field data from snow avalanche fracture lines for slope angle and slab depth (measured perpendicular to the weak layer) were analyzed for different triggering mechanisms. For slope angle, the results showed that the same probability density function (pdf) (of log-logistic type) and range (25 - 55 degrees) apply independent of triggering mechanism. For slab depth, the same pdf (generalized extreme value) applies independent of triggering mechanism. For both slope angle and slab depth, the data skewness differentiated between triggering mechanism and increased with applied triggering load. For slope angle, skewness is lowest for natural triggering by snow loads and highest for triggering from human intervention. For slab depth, the skewness is lowest for natural triggering and highest for a mix of triggers including explosive control with skier triggering being intermediate. The results reveal the effects of triggering mechanism which are important for risk analyses and to guide avalanche forecasting.

McClung, David M.

2013-04-01

413

Gaze angle: a possible mechanism of visual stress in virtual reality headsets.  

PubMed

It is known that some Virtual Reality (VR) head-mounted displays (HMDs) can cause temporary deficits in binocular vision. On the other hand, the precise mechanism by which visual stress occurs is unclear. This paper is concerned with a potential source of visual stress that has not been previously considered with regard to VR systems: inappropriate vertical gaze angle. As vertical gaze angle is raised or lowered the 'effort' required of the binocular system also changes. The extent to which changes in vertical gaze angle alter the demands placed upon the vergence eye movement system was explored. The results suggested that visual stress may depend, in part, on vertical gaze angle. The proximity of the display screens within an HMD means that a VR headset should be in the correct vertical location for any individual user. This factor may explain some previous empirical results and has important implications for headset design. Fortuitously, a reasonably simple solution exists. PMID:9520625

Mon-Williams, M; Plooy, A; Burgess-Limerick, R; Wann, J

1998-03-01

414

An Angle-Based Crossover Tabu Search for Vehicle Routing Problem  

NASA Astrophysics Data System (ADS)

An improved tabu search - crossover tabu search (CTS) is presented which adopt the crossover operator of the genetic algorithm as the diversification strategy, and selecting elite solutions as the intensification strategies. To improve the performances, the angle-based idea of the sweep heuristic is used to confirm the neighborhood, and an object function with punishment. The angle-based CTS is applied for the vehicle routing problem. The simulating results which compared the tradition sweep heuristic and the standard tabu search shows the results got by angle-based CTS are better than those got by other two heuristics. The experiment shows the angle-based CTS has good performance on the vehicle routing problem.

Yang, Ning; Li, Ping; Li, Mingsen

415

A two camera video imaging system with application to parafoil angle of attack measurements  

NASA Astrophysics Data System (ADS)

This paper describes the development of a two-camera, video imaging system for the determination of three-dimensional spatial coordinates from stereo images. This system successfully measured angle of attack at several span-wise locations for large-scale parafoils tested in the NASA Ames 80- by 120-Foot Wind Tunnel. Measurement uncertainty for angle of attack was less than 0.6 deg. The stereo ranging system was the primary source for angle of attack measurements since inclinometers sewn into the fabric ribs of the parafoils had unknown angle offsets acquired during installation. This paper includes discussions of the basic theory and operation of the stereo ranging system, system measurement uncertainty, experimental set-up, calibration results, and test results. Planned improvements and enhancements to the system are also discussed.

Meyn, Larry A.; Bennett, Mark S.

1991-01-01

416

A quantitive method to assess monopulse radar seeker angle measurement performance in the presence of noise jamming  

Microsoft Academic Search

This Paper gives detailed mathematical equations and simulation method to quantify the monopulse radar seeker's standard and Home On Jamming (HOJ) angle measurement performance under multiple jamming, comparison between the theoretical results and simulation results are given at last, it is proved that both the theoretical method and the simulation method are correct in assessing the angle performance of the

Cao Yuan; Fang Weihua; Li Lin; Tian Keyu; Yang Jin

2011-01-01

417

14 CFR 23.1387 - Position light system dihedral angles.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Position light system dihedral angles. 23.1387 Section 23...ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1387 Position light system dihedral angles. (a) Except as...

2013-01-01

418

Small-Angle Scattering at Julich, West Germany.  

National Technical Information Service (NTIS)

Small-angle neutron scattering has essentially become a 'European Science,' with no comparable facilities being available to the American scientific community. The small-angle neutron group at KFA, Julich, West Germany, is involved in research programs in...

H. Herman

1975-01-01

419

Polarisation Angle Anomalies of Lunar Crater Rays and Reiner Gamma  

NASA Astrophysics Data System (ADS)

This contribution describes small-scale variations of the polarisation angle of the light reflected from the lunar surface. These polarisation angle anomalies are observed for several lunar crater ray systems and the Reiner Gamma formation.

Wöhler, C.

2008-03-01

420

Angled Injection: Hybrid Fluid Film Bearings for Cryogenic Applications.  

National Technical Information Service (NTIS)

A computational bulk-flow analysis for prediction of the force coefficients of hybrid fluid film bearings with angled orifice injection is presented. Past measurements on water-lubricated hybrid bearings with angle orifice injection have demonstrated impr...

L. Sanandres

1995-01-01

421

Parity Violation in Forward Angle Elastic Electron Proton Scattering  

SciTech Connect

HAPPEX is a new experiment to probe the strange structure of the nucleon with parity violating electron scattering. We describe the physics motivation, provide an experimental overview and report on the results from the first data run. The asymmetry for the elastic scattering of 3.3 GeV electrons off target protons at a scattering angle of 12.5 degrees was measured to a precision of 15% of itself. The contribution from strange quark form factors was found to be zero within the experimental and theoretical uncertainties.

Krishna Kumar

1999-07-01

422

Measurement of the CKM Angle Alpha at BaBar  

SciTech Connect

We present BABAR experiment studies to measure the CKM angle {alpha} of the Unitarity Triangle. The measurements are based on the B meson decays into the two-body state ({pi}{pi}), the quasi two-body state ({rho}{rho}), and the three-body state ({pi}{sup +}{pi}{sup -}{pi}{sup 0}). The results are obtained from data samples of about 230 million {Upsilon}(4S) {yields} B{bar B} decays collected between 1999 and 2004 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.

Yeche, C.; /Saclay

2006-04-14