National Library of Energy BETA

Sample records for airmass unitless airmass

  1. Lagrangian air-mass tracking with smart balloons during ACE-2 Randy Johnson

    E-Print Network [OSTI]

    Businger, Steven

    Lagrangian air-mass tracking with smart balloons during ACE-2 Randy Johnson National Oceanic and Atmospheric Administration, Air Resources Laboratory, Field Research Division, Idaho Falls, Idaho 83402 Steven Balloon designed at National Oceanic and Atmospheric Administration, Air Resources Laboratory Field

  2. An investigation of linear predictability of the duration of air-mass showers 

    E-Print Network [OSTI]

    Crites, Frank W

    1961-01-01

    rneteorologioaI data Critique DI DA. TA ANALYSIS Study I Study 2 Study 3 Study 4 Study 5 33 37 41 Sz, u. dy 6 St, udy 7 St udy 8 S'. u. dy '-! Study l0 i!V CONCLUS'. OluS ANI) H)uCO&)i~))". 'l&IDA'z, I; ": Coo c'. u s '. , ons Roc ozzzzzzer dat... are deter- mined by the orientation of the antenna during transmission and re- 10 ception. The average echo intensity received from a region of preci- pitation is given (5) by: C K Z P r 2 r where: P = power received, r C = constant depending only...

  3. Relationships Between Emission Sources and Airmass Characteristics in East Asia1 during the TRACE-P Period2

    E-Print Network [OSTI]

    Stanier, Charlie

    . Department of Ecological Engineering, Toyohashi University of Technology, Toyohashi, Japan5 2. Center, such as ethane/CO and23 ethane/propane, by the backward trajectory could well reproduce the emission ratio and their ratio along the trajectory. From25 this analysis, the propane/ethane ratio and propane/acetylene ratio

  4. Supplementary material for "Atmospheric Brown Clouds in the Himalayas: first two years of continuous observations at the

    E-Print Network [OSTI]

    Meskhidze, Nicholas

    simulation of the Khumbu valley meteorology for the analysis of air-mass transport to NCO-P involved

  5. Top-down isoprene emissions over tropical South America inferred from SCIAMACHY and OMI formaldehyde columns

    E-Print Network [OSTI]

    2013-01-01

    of uncer- tainty in formaldehyde air-mass factors overof tropospheric formaldehyde retrieved from spaceborne nadirNorth America using formaldehyde column observations from

  6. DiscussionPaper|DiscussionPaper|DiscussionPaper|DiscussionPaper| Atmos. Chem. Phys. Discuss., 11, 681744, 2011

    E-Print Network [OSTI]

    zonal gradients in mean MBL sub-micron aerosol particle size and composition, carbon10 monoxide, ozone and sulphur dioxide were seen over the campaign, with a generally more variable and polluted coastal layer airmasses having been in recent contact with the local land surface and remote maritime airmasses

  7. Measurement of the Cosmic Microwave Background Polarization with the BICEP Telescope at the South Pole

    E-Print Network [OSTI]

    Takahashi, Yuki David

    2010-01-01

    scans (50 min) Elevation nod (1 min) => Azimuth (deg) Figurescans, a ±0.6 ? elevation “nod” was performed to measuresight airmass (“ elevation nods”), described in §4.2.2. An

  8. Operation Greenhouse. Scientific Director's report of atomic-weapon tests at Eniwetok, 1951. Annex 4. 2. Measurement of surface-air movements associated with atomic blasts

    SciTech Connect (OSTI)

    Rados, R.M.; Bogert, J.C.; Haig, T.O.

    1985-09-01

    The purpose of this project was to record continuous measurements of the surface winds in the vicinity of an atomic blast immediately prior to the blast, during passage of the shock wave, and immediately after the blast with special regard to the blast-induced afterwind following local dissipation of the shock wave. From the data obtained, it was concluded that following an atomic explosion there are two specific causes of air-mass movement. One is related to the shock phenomenon and the other to the rising fireball. It can also be concluded that the heated-thermopile-type and strain-gage-type anemometers could be developed to yield more complete data on the air-mass movement at ground level following an atomic explosion.

  9. Efficiency enhancement of InGaN/GaN solar cells with nanostructures

    SciTech Connect (OSTI)

    Bai, J.; Yang, C. C.; Athanasiou, M.; Wang, T.

    2014-02-03

    We demonstrate InGaN/GaN multi-quantum-well solar cells with nanostructures operating at a wavelength of 520?nm. Nanostructures with a periodic nanorod or nanohole array are fabricated by means of modified nanosphere lithography. Under 1 sun air-mass 1.5 global spectrum illumination, a fill factor of 50 and an open circuit voltage of 1.9?V are achieved in spite of very high indium content in InGaN alloys usually causing degradation of crystal quality. Both the nanorod array and the nanohole array significantly improve the performance of solar cells, while a larger enhancement is observed for the nanohole array, where the conversion efficiency is enhanced by 51%.

  10. Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments

    E-Print Network [OSTI]

    Smette, A; Noll, S; Horst, H; Kausch, W; Kimeswenger, S; Barden, M; Szyszka, C; Jones, A M; Gallenne, A; Vinther, J; Ballester, P; Taylor, J

    2015-01-01

    Context: The interaction of the light from astronomical objects with the constituents of the Earth's atmosphere leads to the formation of telluric absorption lines in ground-based collected spectra. Correcting for these lines, mostly affecting the red and infrared region of the spectrum, usually relies on observations of specific stars obtained close in time and airmass to the science targets, therefore using precious observing time. Aims: We present molecfit, a tool for correcting for telluric absorption lines based on synthetic modelling of the Earth's atmospheric transmission. Molecfit is versatile and can be used with data obtained with various ground-based telescopes and instruments. Methods: Molecfit combines a publicly available radiative transfer code, a molecular line database, atmospheric profiles, and various kernels to model the instrument line spread function. The atmospheric profiles are created by merging a standard atmospheric profile representative of a given observatory's climate, of local m...

  11. Assessing the Feasibility of Creek Daylighting in San Francisco, Part II: A Preliminary Analysis of Yosemite Creek

    E-Print Network [OSTI]

    Smith, Brooke Ray

    2007-01-01

    in cubic feet per second (cfs), C is a unit-less runoffx 1.05 x 1,469 acres = 611 cfs To determine the total volume

  12. Cosmic Shear Measurements with DES Science Verification Data

    E-Print Network [OSTI]

    Becker, M R; MacCrann, N; Krause, E; Eifler, T F; Friedrich, O; Nicola, A; Refregier, A; Amara, A; Bacon, D; Bernstein, G M; Bonnett, C; Bridle, S L; Busha, M T; Chang, C; Dodelson, S; Erickson, B; Evrard, A E; Frieman, J; Gaztanaga, E; Gruen, D; Hartley, W; Jain, B; Jarvis, M; Kacprzak, T; Kirk, D; Kravtsov, A; Leistedt, B; Rykoff, E S; Sabiu, C; Sanchez, C; Seo, H; Sheldon, E; Wechsler, R H; Zuntz, J; Abbott, T; Abdalla, F B; Allam, S; Armstrong, R; Banerji, M; Bauer, A H; Benoit-Levy, A; Bertin, E; Brooks, D; Buckley-Geer, E; Burke, D L; Capozzi, D; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Castander, F J; Crocce, M; Cunha, C E; D'Andrea, C B; da Costa, L N; DePoy, D L; Desai, S; Diehl, H T; Dietrich, J P; Doel, P; Neto, A Fausti; Fernandez, E; Finley, D A; Flaugher, B; Fosalba, P; Gerdes, D W; Gruendl, R A; Gutierrez, G; Honscheid, K; James, D J; Kuehn, K; Kuropatkin, N; Lahav, O; Li, T S; Lima, M; Maia, M A G; March, M; Martini, P; Melchior, P; Miller, C J; Miquel, R; Mohr, J J; Nichol, R C; Nord, B; Ogando, R; Plazas, A A; Reil, K; Romer, A K; Roodman, A; Sako, M; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla-Noarbe, I; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thaler, J; Thomas, D; Vikram, V; Walker, A R

    2015-01-01

    We present measurements of weak gravitational lensing cosmic shear two-point statistics using Dark Energy Survey Science Verification data. We demonstrate that our results are robust to the choice of shear measurement pipeline, either ngmix or im3shape, and robust to the choice of two-point statistic, including both real and Fourier-space statistics. Our results pass a suite of null tests including tests for B-mode contamination and direct tests for any dependence of the two-point functions on a set of 16 observing conditions and galaxy properties, such as seeing, airmass, galaxy color, galaxy magnitude, etc. We furthermore use a large suite of simulations to compute the covariance matrix of the cosmic shear measurements and assign statistical significance to our null tests. We find that our covariance matrix is consistent with the halo model prediction, indicating that it has the appropriate level of halo sample variance. We compare the same jackknife procedure applied to the data and the simulations in orde...

  13. Cosmic Shear Measurements with DES Science Verification Data

    SciTech Connect (OSTI)

    Becker, M. R.

    2015-07-20

    We present measurements of weak gravitational lensing cosmic shear two-point statistics using Dark Energy Survey Science Verification data. We demonstrate that our results are robust to the choice of shear measurement pipeline, either ngmix or im3shape, and robust to the choice of two-point statistic, including both real and Fourier-space statistics. Our results pass a suite of null tests including tests for B-mode contamination and direct tests for any dependence of the two-point functions on a set of 16 observing conditions and galaxy properties, such as seeing, airmass, galaxy color, galaxy magnitude, etc. We use a large suite of simulations to compute the covariance matrix of the cosmic shear measurements and assign statistical significance to our null tests. We find that our covariance matrix is consistent with the halo model prediction, indicating that it has the appropriate level of halo sample variance. We also compare the same jackknife procedure applied to the data and the simulations in order to search for additional sources of noise not captured by the simulations. We find no statistically significant extra sources of noise in the data. The overall detection significance with tomography for our highest source density catalog is 9.7?. Cosmological constraints from the measurements in this work are presented in a companion paper (DES et al. 2015).

  14. Evaluation of Photodiode and Thermopile Pyranometers for Photovoltaic Applications: Preprint

    SciTech Connect (OSTI)

    Sengupta, M.; Gotseff, P.; Stoffel, T.

    2012-09-01

    Accurately determining PV module performance in the field requires measurement of solar irradiance reaching the PV panel at a high level of accuracy and known uncertainty. Silicon detectors used in various solar energy measuring instruments including reference cells are potentially an attractive choice for multiple reasons that include faster responsivity than thermopile detectors, cheaper cost and lower maintenance. The main drawback though is the fact that the silicon detectors are only spectrally responsive in a narrow part of the solar spectrum. Therefore, to determine broadband solar irradiance a calibration factor that converts the narrowband response to broadband is required. Normally this calibration factor is a single number determined under standard conditions but then used for various scenarios including varying air-mass, panel orientation and atmospheric conditions. This would not have been an issue if all wavelengths that form the broadband spectrum responded uniformly to atmospheric constituents. Unfortunately the scattering and absorption signature varies widely across wavelengths and the calibration factor computed under certain test conditions is not appropriate for other conditions. This paper lays out the issues that will arise from the use of silicon detectors for PV performance measurement in the field. We also present a comparison of simultaneous spectral and broadband measurements from silicon and thermopile detectors and estimated measurement errors when using silicon devices for both array performance and resource assessment.

  15. Performance Testing using Silicon Devices - Analysis of Accuracy: Preprint

    SciTech Connect (OSTI)

    Sengupta, M.; Gotseff, P.; Myers, D.; Stoffel, T.

    2012-06-01

    Accurately determining PV module performance in the field requires accurate measurements of solar irradiance reaching the PV panel (i.e., Plane-of-Array - POA Irradiance) with known measurement uncertainty. Pyranometers are commonly based on thermopile or silicon photodiode detectors. Silicon detectors, including PV reference cells, are an attractive choice for reasons that include faster time response (10 us) than thermopile detectors (1 s to 5 s), lower cost and maintenance. The main drawback of silicon detectors is their limited spectral response. Therefore, to determine broadband POA solar irradiance, a pyranometer calibration factor that converts the narrowband response to broadband is required. Normally this calibration factor is a single number determined under clear-sky conditions with respect to a broadband reference radiometer. The pyranometer is then used for various scenarios including varying airmass, panel orientation and atmospheric conditions. This would not be an issue if all irradiance wavelengths that form the broadband spectrum responded uniformly to atmospheric constituents. Unfortunately, the scattering and absorption signature varies widely with wavelength and the calibration factor for the silicon photodiode pyranometer is not appropriate for other conditions. This paper reviews the issues that will arise from the use of silicon detectors for PV performance measurement in the field based on measurements from a group of pyranometers mounted on a 1-axis solar tracker. Also we will present a comparison of simultaneous spectral and broadband measurements from silicon and thermopile detectors and estimated measurement errors when using silicon devices for both array performance and resource assessment.

  16. Mapping and simulating systematics due to spatially-varying observing conditions in DES Science Verification data

    E-Print Network [OSTI]

    Leistedt, B; Elsner, F; Benoit-Lévy, A; Amara, A; Bauer, A H; Becker, M R; Bonnett, C; Bruderer, C; Busha, M T; Kind, M Carrasco; Chang, C; Crocce, M; da Costa, L N; Gaztanaga, E; Huff, E M; Lahav, O; Palmese, A; Percival, W J; Refregier, A; Ross, A J; Rozo, E; Rykoff, E S; Sánchez, C; Sadeh, I; Sevilla-Noarbe, I; Sobreira, F; Suchyta, E; Swanson, M E C; Wechsler, R H; Abdalla, F B; Allam, S; Banerji, M; Bernstein, G M; Bernstein, R A; Bertin, E; Bridle, S L; Brooks, D; Buckley-Geer, E; Burke, D L; Capozzi, D; Rosell, A Carnero; Carretero, J; Cunha, C E; D'Andrea, C B; DePoy, D L; Desai, S; Diehl, H T; Doel, P; Eifler, T F; Evrard, A E; Neto, A Fausti; Flaugher, B; Fosalba, P; Frieman, J; Gerdes, D W; Gruen, D; Gruendl, R A; Gutierrez, G; Honscheid, K; James, D J; Jarvis, M; Kent, S; Kuehn, K; Kuropatkin, N; Li, T S; Lima, M; Maia, M A G; March, M; Marshall, J L; Martini, P; Melchior, P; Miller, C J; Miquel, R; Nichol, R C; Nord, B; Ogando, R; Plazas, A A; Reil, K; Romer, A K; Roodman, A; Sanchez, E; Santiago, B; Scarpine, V; Schubnell, M; Smith, R C; Soares-Santos, M; Tarle, G; Thaler, J; Thomas, D; Vikram, V; Walker, A R; Wester, W; Zhang, Y; Zuntz, J

    2015-01-01

    Spatially-varying depth and characteristics of observing conditions, such as seeing, airmass, or sky background, are major sources of systematic uncertainties in modern galaxy survey analyses, in particular in deep multi-epoch surveys. We present a framework to extract and project these sources of systematics onto the sky, and apply it to the Dark Energy Survey (DES) to map the observing conditions of the Science Verification (SV) data. The resulting distributions and maps of sources of systematics are used in several analyses of DES SV to perform detailed null tests with the data, and also to incorporate systematics in survey simulations. We illustrate the complementarity of these two approaches by comparing the SV data with the BCC-UFig, a synthetic sky catalogue generated by forward-modelling of the DES SV images. We analyse the BCC-UFig simulation to construct galaxy samples mimicking those used in SV galaxy clustering studies. We show that the spatially-varying survey depth imprinted in the observed gala...

  17. Sloan Digital Sky Survey photometric telescope automation and observing software

    SciTech Connect (OSTI)

    Eric H. Neilsen, Jr. et al.

    2002-10-16

    The photometric telescope (PT) provides observations necessary for the photometric calibration of the Sloan Digital Sky Survey (SDSS). Because the attention of the observing staff is occupied by the operation of the 2.5 meter telescope which takes the survey data proper, the PT must reliably take data with little supervision. In this paper we describe the PT's observing program, MOP, which automates most tasks necessary for observing. MOP's automated target selection is closely modeled on the actions a human observer might take, and is built upon a user interface that can be (and has been) used for manual operation. This results in an interface that makes it easy for an observer to track the activities of the automating procedures and intervene with minimum disturbance when necessary. MOP selects targets from the same list of standard star and calibration fields presented to the user, and chooses standard star fields covering ranges of airmass, color, and time necessary to monitor atmospheric extinction and produce a photometric solution. The software determines when additional standard star fields are unnecessary, and selects survey calibration fields according to availability and priority. Other automated features of MOP, such as maintaining the focus and keeping a night log, are also built around still functional manual interfaces, allowing the observer to be as active in observing as desired; MOP's automated features may be used as tools for manual observing, ignored entirely, or allowed to run the telescope with minimal supervision when taking routine data.

  18. Nanostructured Cobalt Oxide Clusters in Mesoporous Silica as Efficient Oxygen-Evolving Catalysts

    SciTech Connect (OSTI)

    Jiao, Feng; Frei, Heinz

    2009-01-01

    The development of integrated artificial photosynthetic systems for the direct conversion of carbon dioxide and water to fuel depends on the availability of efficient and robust catalysts for the chemical transformations. Catalysts need to exhibit turnover frequency (TOF) and density (hence size) commensurate with the solar flux at ground level (1000Wm2, airmass (AM) 1.5)[1]to avoid wasting of incidentsolar photons. For example, a catalyst with a TOF of 100 s1 requires a density of one catalytic site per square nanometer. Catalysts with lower rates or taking up a larger space will require a high-surface-area, nanostructured support that affords tens to hundreds of catalytic sites per square nanometer. Furthermore, catalysts need to operate close to the thermodynamic potential of the redox reaction so that amaximum fraction of the solar photon energy is converted to chemical energy. Stability considerations favor all-inorganic oxide materials, as does avoidance of harsh reaction conditions of pH value or temperature.

  19. High-efficiency GaInP/GaAs tandem solar cells

    SciTech Connect (OSTI)

    Bertness, K.A.; Friedman, D.J.; Kurtz, S.R.; Kibbler, A.E.; Kramer, C.; Olson, J.M.

    1994-12-01

    GaInP/GaAs tandem solar cells have achieved new record efficiencies, specifically 25.7% under air-mass 0 (AM0) illumination, 29.5% under AM 1.5 global (AM1.5G) illumination, and 30.2% at 140-180x concentration under AM 1.5 direct (AM1.5D) illumination. These values are the highest two-terminal efficiencies achieved by any solar cell under these illumination conditions. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance. 31 refs.

  20. Atmospheric Dispersion Effects in Weak Lensing Measurements

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Plazas, Andrés Alejandro; Bernstein, Gary

    2012-10-01

    The wavelength dependence of atmospheric refraction causes elongation of finite-bandwidth images along the elevation vector, which produces spurious signals in weak gravitational lensing shear measurements unless this atmospheric dispersion is calibrated and removed to high precision. Because astrometric solutions and PSF characteristics are typically calibrated from stellar images, differences between the reference stars' spectra and the galaxies' spectra will leave residual errors in both the astrometric positions (dr) and in the second moment (width) of the wavelength-averaged PSF (dv) for galaxies.We estimate the level of dv that will induce spurious weak lensing signals in PSF-corrected galaxy shapes that exceed themore »statistical errors of the DES and the LSST cosmic-shear experiments. We also estimate the dr signals that will produce unacceptable spurious distortions after stacking of exposures taken at different airmasses and hour angles. We also calculate the errors in the griz bands, and find that dispersion systematics, uncorrected, are up to 6 and 2 times larger in g and r bands,respectively, than the requirements for the DES error budget, but can be safely ignored in i and z bands. For the LSST requirements, the factors are about 30, 10, and 3 in g, r, and i bands,respectively. We find that a simple correction linear in galaxy color is accurate enough to reduce dispersion shear systematics to insignificant levels in the r band for DES and i band for LSST,but still as much as 5 times than the requirements for LSST r-band observations. More complex corrections will likely be able to reduce the systematic cosmic-shear errors below statistical errors for LSST r band. But g-band effects remain large enough that it seems likely that induced systematics will dominate the statistical errors of both surveys, and cosmic-shear measurements should rely on the redder bands.« less

  1. Atmospheric Dispersion Effects in Weak Lensing Measurements

    SciTech Connect (OSTI)

    Plazas, Andrés Alejandro; Bernstein, Gary

    2012-10-01

    The wavelength dependence of atmospheric refraction causes elongation of finite-bandwidth images along the elevation vector, which produces spurious signals in weak gravitational lensing shear measurements unless this atmospheric dispersion is calibrated and removed to high precision. Because astrometric solutions and PSF characteristics are typically calibrated from stellar images, differences between the reference stars' spectra and the galaxies' spectra will leave residual errors in both the astrometric positions (dr) and in the second moment (width) of the wavelength-averaged PSF (dv) for galaxies.We estimate the level of dv that will induce spurious weak lensing signals in PSF-corrected galaxy shapes that exceed the statistical errors of the DES and the LSST cosmic-shear experiments. We also estimate the dr signals that will produce unacceptable spurious distortions after stacking of exposures taken at different airmasses and hour angles. We also calculate the errors in the griz bands, and find that dispersion systematics, uncorrected, are up to 6 and 2 times larger in g and r bands,respectively, than the requirements for the DES error budget, but can be safely ignored in i and z bands. For the LSST requirements, the factors are about 30, 10, and 3 in g, r, and i bands,respectively. We find that a simple correction linear in galaxy color is accurate enough to reduce dispersion shear systematics to insignificant levels in the r band for DES and i band for LSST,but still as much as 5 times than the requirements for LSST r-band observations. More complex corrections will likely be able to reduce the systematic cosmic-shear errors below statistical errors for LSST r band. But g-band effects remain large enough that it seems likely that induced systematics will dominate the statistical errors of both surveys, and cosmic-shear measurements should rely on the redder bands.

  2. DISCOVERY OF A DYNAMICAL COLD POINT IN THE HEART OF THE SAGITTARIUS dSph GALAXY WITH OBSERVATIONS FROM THE APOGEE PROJECT

    SciTech Connect (OSTI)

    Majewski, Steven R.; Hasselquist, Sten; Nidever, David L. E-mail: sh6cy@virginia.edu; and others

    2013-11-01

    The dynamics of the core of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy are explored using high-resolution (R ? 22, 500), H-band, near-infrared spectra of over 1000 giant stars in the central 3 deg{sup 2} of the system, of which 328 are identified as Sgr members. These data, among some of the earliest observations from the Sloan Digital Sky Survey III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) and the largest published sample of high resolution Sgr dSph spectra to date, reveal a distinct gradient in the velocity dispersion of Sgr from 11 to 14 km s{sup –1} for radii >0.°8 from center to a dynamical cold point of 8 km s{sup –1} in the Sgr center—a trend differing from that found in previous kinematical analyses of Sgr over larger scales that suggests a more or less flat dispersion profile at these radii. Well-fitting mass models with either cored and cusped dark matter distributions can be found to match the kinematical results, although the cored profile succeeds with significantly more isotropic stellar orbits than required for a cusped profile. It is unlikely that the cold point reflects an unusual mass distribution. The dispersion gradient may arise from variations in the mixture of populations with distinct kinematics within the dSph; this explanation is suggested (e.g., by detection of a metallicity gradient across similar radii), but not confirmed, by the present data. Despite these remaining uncertainties about their interpretation, these early test data (including some from instrument commissioning) demonstrate APOGEE's usefulness for precision dynamical studies, even for fields observed at extreme airmasses.

  3. El Roque de Los Muchachos Site Characteristics. III. Analysis of Atmospheric Dust and Aerosol Extinction

    E-Print Network [OSTI]

    G. Lombardi; V. Zitelli; S. Ortolani; M. Pedani; A. Ghedina

    2008-03-26

    Canary Islands are normally interested by dominant North-East winds that, in some meteorological conditions, can transport sand at high altitude from the Sahara desert. The dust may affect the efficiency of the telescopes and decreases the transparency of the sky. In order to maximize the scientific return of the telescopes located at the ORM, we present an analysis of the atmospheric dust content and its effects on astronomical observations. B, V and I dust aerosol astronomical extinction are derived. Using a 5 years series database of data taken from the four channel TNG dust monitor, we compute a mean hourly and daily values of the dust content. We have detected particles having size 0.3, 0.5, 1.0 and 5.0 um. Using a power law we have derived the content of 10.0 um particles. We found a typical local dust concentration ranging from 3x10^6 particles per cubic meter at 0.3 um, to 10^3 at 5.0 um and 10 at 10.0 um, increasing up to 3 order of magnitudes during the dust storms, with a relative higher increase of 1.0, 5.0 and 10.0 um particles. The number of local dust storm events is the same in winter- and summertime, but, the average background and storm-related increases in the dust concentration in summer are significantly higher than in winter. In a uniform approximation, during the dust storms, an average height of the dust layer of 2.5 km above the telescope is inferred. During the sand storms La Palma Island is affected by an almost uniform layer extending up to 5 km above the sea level, down, at least the height of the telescope. The visible extinction is dominated by particles at 1.0, 5.0 and 10.0 um. In agreement with the results from Carlsberg Automatic Meridian Circle (CAMC) we find a typical extinction during dust storms of about 0.2 mag/airmass.

  4. Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign

    SciTech Connect (OSTI)

    Shilling, John E.; Zaveri, Rahul A.; Fast, Jerome D.; Kleinman, Lawrence I.; Alexander, M. L.; Canagaratna, Manjula R.; Fortner, Edward; Hubbe, John M.; Jayne, John T.; Sedlacek, Art; Setyan, Ari; Springston, S.; Worsnop, Douglas R.; Zhang, Qi

    2013-02-21

    The CARES campaign was conducted during June, 2010 in the vicinity of Sacramento, California to study aerosol formation and aging in a region where anthropogenic and biogenic emissions regularly mix. Here, we describe measurements from an Aerodyne High Resolution Aerosol Mass Spectrometer (AMS), an Ionicon Proton Transfer Reaction Mass Spectrometer (PTR-MS), and trace gas detectors (CO, NO, NOx) deployed on the G-1 research aircraft to investigate ambient gas- and particle-phase chemical composition. AMS measurements showed that the particle phase is dominated by organic aerosol (OA) (85% on average) with smaller concentrations of sulfate (5%), nitrate (6%) and ammonium (3%) observed. PTR-MS data showed that isoprene dominated the biogenic volatile organic compound concentrations (BVOCs), with monoterpene concentrations generally below the detection limit. Using two different metrics, median OA concentrations and the slope of plots of OA vs. CO concentrations (i.e., ?OA/?CO), we contrast organic aerosol evolution on flight days with different prevailing meteorological conditions to elucidate the role of anthropogenic and biogenic emissions on OA formation. Airmasses influenced predominantly by biogenic emissions had median OA concentrations of 2.9 ?g/m3 and near zero ?OA/?CO. Those influenced predominantly by anthropogenic emissions had median OA concentrations of 4.7 ?g/m3 and ?OA/?CO ratios of 35 - 44 ?g/m3ppmv. When biogenic and anthropogenic emissions mix, OA levels are dramatically enhanced with median OA concentrations of 11.4 ?g/m3 and ?OA/?CO ratios of 77 - 157 ?g/m3ppmv. Taken together, our observations show that production of OA is enhanced when anthropogenic emissions from Sacramento mix with isoprene-rich air from the foothills. A strong, non-linear dependence of SOA yield from isoprene is the mechanistic explanation for this enhancement most consistent with both the gas- and particle-phase data. If these observations are found to be robust in other seasons and in areas outside of Sacramento, regional and global aerosol modules will need to incorporate NOx-dependent SOA yields into their algorithms. Regardless of the mechanism, accurately predicting OA mass concentrations and their effect on radiation balance will require an accurate accounting of the interactions of biogenic and anthropogenic emissions.

  5. This un-edited manuscript has been accepted for publication in Biophysical Journal and is freely available on BioFast at http://www.biophysj.org. The final copyedited version of

    E-Print Network [OSTI]

    this conversion factor by ; it is measured in fluorescence units per fluorescent protein (or, more generally such data both the fluorescence conversion factor and an estimate of the measurement error in the data. Our of tagged pro- teins or immunoblots, is usually limited to unit-less ratios of expression levels

  6. RESEARCH PAPER Fouling and its mitigation in silicon microchannels used

    E-Print Network [OSTI]

    Kandlikar, Satish

    - persions in water were performed in rectangular, silicon microchannels having hydraulic diameters between diameter (m) Dh hydraulic diameter (m) e elementary electric charge (coulomb) Eel electrostatic interaction in determining zeta potential (unitless) eo dielectric permittivity of vacuum (F/m) er relative dielectric

  7. Appendix. Variable descriptions, code, unit of measure, and descriptive statistics, which include the mean, standard deviation (SD), and range of values in the data set.

    E-Print Network [OSTI]

    Poff, N. LeRoy

    .37­246.26 Median annual coefficient of variation of daily flows C.H.CV Unitless 1.66 0.7 0.77­4.63 Proportion­0.77 Proportion of fast-water habitat (riffles, runs, etc) within the reach R.H.Fast Proportion 0.51 0.28 0­1 Riparian (nonclimatic) Proportion of all vegetation types along of riparian zone of reach R

  8. Engineer reconnaissance with a video camera: feasibility study 

    E-Print Network [OSTI]

    Bergner, Kirk Michael

    1990-01-01

    an object; (b) measur' ng the image of the object on the processed photographs; and (c) reducing the measurements to some useful form" (Moffitt and Mikhail, 1988). Pixel: One of the square, or rectangular, light sensitive areas on a solid state pickup... "painted polygons". Rectification: A procedure for eliminating tilt displacements (Moffitt and Mikhail, 1988). In the case of slope distances it implies the use of the horizontal or vertical components. Representative Fraction (RF): A unitless ratio...

  9. WHAT'S OVER THE HORIZON? THE FUTURE OF MAGNETIC

    E-Print Network [OSTI]

    ¨ Carbon walls not suited for nuclear environment ¤ Erosion ¤ Co-deposition of tritium ¨ Need to limit+ Energy [eV] 100 101 102 10-1 10-2 10-3 10-4 10-5 1 10 100 1000 eV 1e-05 0.0001 0.001 0.01 0.1 unitless 1.M. Wallace, IAP2014 R=0.68m, a=0.22m, B=8T #12;Vertical target divertor spreads out heat flux footprint

  10. Simulated effects of changes in the infiltration rate and the hydraulic conductivity structure on the location and configuration of the water table at Yucca Mountain, Nevada 

    E-Print Network [OSTI]

    Jasek, Noreen Ann

    1991-01-01

    dh/dl is the hydraulic gradient where h is the hydraulic head and 1 is the length of the flow path over which the head change is measured. Because both h and 1 have units of length, dh/dl itself is unitless. The deterministic flow equation used... of the steep gradients causing the step- like configuration have been related to two mechanisms: ground water barriers or gradual permeability variations. This study was designed to determine if either or both of the mechanisms could produce the observed...

  11. High efficiency novel window air conditioner

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bansal, Pradeep

    2015-07-24

    This paper presents the technical development of a high efficiency window air conditioner. In order to achieve higher energy efficiency ratio (EER), the original capacity of the R410A unit was downgraded by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. The other subsequent major modifications included – the AC fan motor being replaced with a brushless high efficiency electronically commuted motor (ECM) motor, the capillary tube being replaced with a needle valve to better control the refrigerant flow and refrigerant set points, andmore »R410A being replaced with drop-in environmentally friendly binary mixture of R32 (85% molar concentration)/R125 (15% molar concentration). All these modifications resulted in significant EER enhancement of the modified unit.« less

  12. The phase diagram and hardness of carbon nitrides

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dong, Huafeng; Oganov, Artem R.; Moscow Inst. of Physics and Technology; Northwestern Polytechnical Univ., Xi'an; Zhu, Qiang; Qian, Guang-Rui

    2015-05-06

    Novel superhard materials, especially those with superior thermal and chemical stability, are needed to replace diamond. Carbon nitrides (C-N), which are likely to possess these characteristics and have even been expected to be harder than diamond, are excellent candidates. Here we report three new superhard and thermodynamically stable carbon nitride phases. Based on a systematic evolutionary structure searches, we report a complete phase diagram of the C-N system at 0–300 GPa and analyze the hardest metastable structures. Surprisingly, we find that at zero pressure, the earlier proposed graphitic-C3N4 structure (P6-bar m2) is dynamically unstable, and we find the lowest-energy structuremore »based on s-triazine unit and s-heptazine unit.« less

  13. Analysis of the microwave, terahertz, and far infrared spectra of monodeuterated methanol CH{sub 2}DOH up to J = 26, K = 11, and o{sub 1}

    SciTech Connect (OSTI)

    Coudert, L. H., E-mail: laurent.coudert@lisa.u-pec.fr [Laboratoire Inter-universitaire des Systèmes Atmosphériques, UMR 7583 du CNRS, Universités Paris Est Créteil et Paris Diderot, 61 Avenue du Général de Gaulle, 94010 Créteil Cedex (France); Zemouli, M. [Laboratoire d'Études Physico-Chimiques, Université Dr. T. Moulay de Saïda, Saïda 20000 (Algeria)] [Laboratoire d'Études Physico-Chimiques, Université Dr. T. Moulay de Saïda, Saïda 20000 (Algeria); Motiyenko, R. A.; Margulès, L. [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS - Université Lille I, Bât. P5, 59655 Villeneuve d'Ascq Cedex (France)] [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS - Université Lille I, Bât. P5, 59655 Villeneuve d'Ascq Cedex (France); Klee, S. [Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany)] [Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany)

    2014-02-14

    The first theoretical approach aimed at accounting for the energy levels of a non-rigid molecule displaying asymmetric-top asymmetric-frame internal rotation is developed. It is applied to a line position analysis of the high-resolution spectrum of the non-rigid CH{sub 2}DOH molecule and allows us to carry out a global analysis of a data set consisting of already available data and of microwave and far infrared transitions measured in this work. The analysis is restricted to the three lowest lying torsional levels (e{sub 0}, e{sub 1}, and o{sub 1}), to K ? 11, and to J ? 26. For the 8211 fitted lines, the unitless standard deviation is 2.4 and 103 parameters are determined including kinetic energy, hindering potential, and distortion effects parameters.

  14. LONG-TERM OPTICAL OBSERVATIONS OF TWO LMXBs: UW CrB (=MS 1603+260) AND V1408 Aql (=4U 1957+115)

    SciTech Connect (OSTI)

    Mason, Paul A. [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States); Robinson, Edward L.; Bayless, Amanda J. [Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712 (United States); Hakala, Pasi J. [Finnish Centre for Astronomy with ESO, Vaeisaelaentie 20, FIN-21500 Piikkioe, University of Turku (Finland)

    2012-10-01

    We present new optical photometry of two low-mass X-ray binary stars, UW CrB (MS 1603+260) and V1408 Aql (4U 1957+115). UW CrB is an eclipsing binary and we refine its eclipse ephemeris and measure an upper limit to the rate of change of its orbital period, | P-dot | < 4.2 Multiplication-Sign 10{sup -11} (unitless). The light curve of UW CrB shows optical counterparts of type I X-ray bursts. We tabulate the times, orbital phases, and fluences of 33 bursts and show that the optical flux in the bursts comes primarily from the accretion disk, not from the secondary star. The new observations are consistent with a model in which the accretion disk in UW CrB is asymmetric and precesses in the prograde direction with a period of {approx}5.5 days. The light curve of V1408 Aql has a low-amplitude modulation at its 9.33 hr orbital period. The modulation remained a nearly pure sine curve in the new data as it was in 1984 and 2008, but its mean amplitude was lower, 18% against 23% in the earlier data. A model in which the orbital modulation is caused by the varying aspect of the heated face of the secondary star continues to give an excellent fit to the light curve. We derive a much improved orbital ephemeris for the system.