WorldWideScience

Sample records for analyzing solar reflective

  1. An integrated empirical and modeling methodology for analyzing solar reflective roof technologies on commercial buildings

    International Nuclear Information System (INIS)

    Buildings impact the environment in many ways as a result of both their energy use and material consumption. In urban areas, the emission of greenhouse gases and the creation of microclimates are among their most prominent impacts so the adoption of building design strategies and materials that address both these issues will lead to significant reductions in a building's overall environmental impact. This report documents the energy savings and surface temperature reduction achieved by replacing an existing commercial building's flat roof with a more reflective 'cool roof' surface material. The research methodology gathered data on-site (surface temperatures and reflectivity) and used this in conjunction with the as-built drawings to construct a building energy simulation model. A 20-year cost benefit analysis (CBA) was conducted to determine the return on investment (ROI) for the new cool roof construction based on the energy simulation results. The results of the EnergyPlus trademark simulation modeling revealed that reductions of 1.3-1.9% and 2.6-3.8% of the total monthly electricity consumption can be achieved from the 50% cool roof replacement already implemented and a future 100% roof replacement, respectively. This corresponds to a saving of approximately $22,000 per year in energy costs at current prices and a consequent 9-year payback period for the added cost of installing the 100% cool roof. The environmental benefits associated with these electricity savings, particularly the reductions in environmental damage and peak-time electricity demand, represent the indirect benefits of the cool roof system. (author)

  2. Reflections of ions in electrostatic analyzers: A case study with New Horizons/Solar Wind Around Pluto

    International Nuclear Information System (INIS)

    Electrostatic analyzers (ESAs), in various forms, are used to measure plasma in a range of applications. In this article, we describe how ions reflect from the interior surfaces of an ESA, the detection of which constitutes a fundamentally nonideal response of ESAs. We demonstrate this effect by comparing laboratory data from a real ESA-based space instrument, the Solar Wind Around Pluto (SWAP) instrument, aboard the NASA New Horizons spacecraft, to results from a model based on quantum mechanical simulations of particles reflected from the instrument's surfaces combined with simulations of particle trajectories through the instrument's applied electrostatic fields. Thus, we show, for the first time, how reflected ions in ESAs lead to nonideal effects that have important implications for understanding the data returned by these instruments, as well as for designing new low-background ESA-based instruments. Specifically, we show that the response of SWAP widens considerably below a level of 10-3 of the peak response. Thus, a direct measurement of a plasma distribution with SWAP will have an energy-dependent background on the order of ≤10-3 of the peak of the signal due to that distribution. We predict that this order of magnitude estimate for the background applies to a large number of ESA-based instruments because ESAs operate using a common principle. However, the exact shape of the energy-dependent response will be different for different instruments. The principle of operation is that ions outside the ideal range of energy-per-charge are deflected into the walls of the ESA. Therefore, we propose that a new design paradigm is necessary to mitigate the effect of ion reflections and thus accurately and directly measure the energy spectrum of a plasma using ESAs. In this article, we build a framework for minimizing the effect of ion reflections in the design of new ESAs. Through the use of existing computer simulation software, a design team can use our method to

  3. Reflections of ions in electrostatic analyzers: a case study with New Horizons/Solar Wind Around Pluto.

    Science.gov (United States)

    Randol, B M; Ebert, R W; Allegrini, F; McComas, D J; Schwadron, N A

    2010-11-01

    Electrostatic analyzers (ESAs), in various forms, are used to measure plasma in a range of applications. In this article, we describe how ions reflect from the interior surfaces of an ESA, the detection of which constitutes a fundamentally nonideal response of ESAs. We demonstrate this effect by comparing laboratory data from a real ESA-based space instrument, the Solar Wind Around Pluto (SWAP) instrument, aboard the NASA New Horizons spacecraft, to results from a model based on quantum mechanical simulations of particles reflected from the instrument's surfaces combined with simulations of particle trajectories through the instrument's applied electrostatic fields. Thus, we show, for the first time, how reflected ions in ESAs lead to nonideal effects that have important implications for understanding the data returned by these instruments, as well as for designing new low-background ESA-based instruments. Specifically, we show that the response of SWAP widens considerably below a level of 10(-3) of the peak response. Thus, a direct measurement of a plasma distribution with SWAP will have an energy-dependent background on the order of ≤10(-3) of the peak of the signal due to that distribution. We predict that this order of magnitude estimate for the background applies to a large number of ESA-based instruments because ESAs operate using a common principle. However, the exact shape of the energy-dependent response will be different for different instruments. The principle of operation is that ions outside the ideal range of energy-per-charge are deflected into the walls of the ESA. Therefore, we propose that a new design paradigm is necessary to mitigate the effect of ion reflections and thus accurately and directly measure the energy spectrum of a plasma using ESAs. In this article, we build a framework for minimizing the effect of ion reflections in the design of new ESAs. Through the use of existing computer simulation software, a design team can use our method

  4. Analyzing the effect of the longwave emissivity and solar reflectance of building envelopes on energy-saving in buildings in various climates

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhiyang; Zhang, Xiong [Key Laboratory of Advanced Civil Engineering Materials of Education Ministry, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2011-01-15

    A dynamic computer simulation is carried out in the climates of 35 cities distributed around the world. The variation of the annual air-conditioning energy loads due to changes in the longwave emissivity and the solar reflectance of the building envelopes is studied to find the most appropriate exterior building finishes in various climates (including a tropical climate, a subtropical climate, a mountain plateau climate, a frigid-temperate climate and a temperate climate). Both the longwave emissivity and the solar reflectance are set from 0.1 to 0.9 with an interval of 0.1 in the simulation. The annual air-conditioning energy loads trends of each city are listed in a chart. The results show that both the longwave emissivity and the solar reflectance of building envelopes play significant roles in energy-saving for buildings. In tropical climates, the optical parameters of the building exterior surface affect the building energy-saving most significantly. In the mountain plateau climates and the subarctic climates, the impacts on energy-saving in buildings due to changes in the longwave emissivity and the solar reflectance are still considerable, but in the temperate continental climates and the temperate maritime climates, only limited effects are seen. (author)

  5. MODIS Solar Reflective Calibration Traceability

    Science.gov (United States)

    Xiong, Xiaoxiong; Butler, Jim

    2009-01-01

    Long-term climate data records often consist of observations made by multiple sensors. It is, therefore, extremely important to have instrument overlap, to be able to track instrument stability, to quantify, measurement uncertainties, and to establish absolute scale traceable to the International System of Units (SI). The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument for both the Terra and Aqua missions, which were launched in December 1999 and May 2002, respectively. It has 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2 micrometers and observes the Earth at three nadir spatial resolutions: 0.25km, 0.5km, and 1km. MODIS RSB on-orbit calibration is reflectance based with reference to the bidirectional reflectance factor (BRF) of its on-board solar diffuser (SD). The SD BRF characterization was made pre-launch by the instrument vendor using reference samples traceable directly to the National Institute of Standards and Technology (NIST). On-orbit SD reflectance degradation is tracked by an on-board solar diffuser monitor (SDSM). This paper provides details of this calibration chain, from prelaunch to on-orbit operation, and associated uncertainty assessments. Using MODIS as an example, this paper also discusses challenges and key design requirements for future missions developed for accurate climate studies.

  6. MODIS solar reflective calibration traceability

    Science.gov (United States)

    Xiong, Xiaoxiong; Butler, Jim

    2009-08-01

    Long-term climate data records often consist of observations made by multiple sensors. It is, therefore, extremely important to have instrument overlap, to be able to track instrument stability, to quantify measurement uncertainties, and to establish an absolute measurement scale traceable to the International System of Units (SI). The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument for both the Terra and Aqua missions, which were launched in December 1999 and May 2002, respectively. It has 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μm and observes the Earth at three nadir spatial resolutions: 0.25km, 0.5km, and 1km. MODIS RSB on-orbit calibration is reflectance based with reference to the bi-directional reflectance factor (BRF) of its on-board solar diffuser (SD). The SD BRF characterization was made pre-launch by the instrument vendor using reference samples traceable directly to the National Institute of Standards and Technology (NIST). On-orbit SD reflectance degradation is tracked by an on-board solar diffuser stability monitor (SDSM). This paper provides details of this calibration chain, from pre-launch to on-orbit operation, and associated uncertainty assessments. Using MODIS as an example, this paper also discusses challenges and key design requirements for future missions developed for accurate climate studies.

  7. The Solar Wind Ion Analyzer for MAVEN

    Science.gov (United States)

    Halekas, J. S.; Taylor, E. R.; Dalton, G.; Johnson, G.; Curtis, D. W.; McFadden, J. P.; Mitchell, D. L.; Lin, R. P.; Jakosky, B. M.

    2015-12-01

    The Solar Wind Ion Analyzer (SWIA) on the MAVEN mission will measure the solar wind ion flows around Mars, both in the upstream solar wind and in the magneto-sheath and tail regions inside the bow shock. The solar wind flux provides one of the key energy inputs that can drive atmospheric escape from the Martian system, as well as in part controlling the structure of the magnetosphere through which non-thermal ion escape must take place. SWIA measurements contribute to the top level MAVEN goals of characterizing the upper atmosphere and the processes that operate there, and parameterizing the escape of atmospheric gases to extrapolate the total loss to space throughout Mars' history. To accomplish these goals, SWIA utilizes a toroidal energy analyzer with electrostatic deflectors to provide a broad 360∘×90∘ field of view on a 3-axis spacecraft, with a mechanical attenuator to enable a very high dynamic range. SWIA provides high cadence measurements of ion velocity distributions with high energy resolution (14.5 %) and angular resolution (3.75∘×4.5∘ in the sunward direction, 22.5∘×22.5∘ elsewhere), and a broad energy range of 5 eV to 25 keV. Onboard computation of bulk moments and energy spectra enable measurements of the basic properties of the solar wind at 0.25 Hz.

  8. The MAVEN Solar Wind Electron Analyzer

    Science.gov (United States)

    Mitchell, D. L.; Mazelle, C.; Sauvaud, J.-A.; Thocaven, J.-J.; Rouzaud, J.; Fedorov, A.; Rouger, P.; Toublanc, D.; Taylor, E.; Gordon, D.; Robinson, M.; Heavner, S.; Turin, P.; Diaz-Aguado, M.; Curtis, D. W.; Lin, R. P.; Jakosky, B. M.

    2016-04-01

    The MAVEN Solar Wind Electron Analyzer (SWEA) is a symmetric hemispheric electrostatic analyzer with deflectors that is designed to measure the energy and angular distributions of 3-4600-eV electrons in the Mars environment. This energy range is important for impact ionization of planetary atmospheric species, and encompasses the solar wind core and halo populations, shock-energized electrons, auroral electrons, and ionospheric primary photoelectrons. The instrument is mounted at the end of a 1.5-meter boom to provide a clear field of view that spans nearly 80 % of the sky with ˜20° resolution. With an energy resolution of 17 % (Δ E/E), SWEA readily distinguishes electrons of solar wind and ionospheric origin. Combined with a 2-second measurement cadence and on-board real-time pitch angle mapping, SWEA determines magnetic topology with high (˜8-km) spatial resolution, so that local measurements of the plasma and magnetic field can be placed into global context.

  9. Solar photovoltaic reflective trough collection structure

    Science.gov (United States)

    Anderson, Benjamin J.; Sweatt, William C.; Okandan, Murat; Nielson, Gregory N.

    2015-11-19

    A photovoltaic (PV) solar concentration structure having at least two troughs encapsulated in a rectangular parallelepiped optical plastic structure, with the troughs filled with an optical plastic material, the troughs each having a reflective internal surface and approximately parabolic geometry, and the troughs each including photovoltaic cells situated so that light impinging on the optical plastic material will be concentrated onto the photovoltaic cells. Multiple structures can be connected to provide a solar photovoltaic collection system that provides portable, efficient, low-cost electrical power.

  10. Solar reflectance, transmittance, and absorptance of common materials

    Energy Technology Data Exchange (ETDEWEB)

    Butler, B.L.; Call, P.J.; Jorgensen, G.L.; Pettit, R.B.

    1979-10-01

    The solar reflectance, transmittance, and absorptance of common materials used for solar collector fabrication have been compiled for easy reference. The data are derived from solar weighted averaging techniques and can be used for initial calculations of collector performance.

  11. Surface roughness effects on the solar reflectance of cool asphalt shingles

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Berdahl, Paul; Akbari, Hashem; Jacobs, Jeffry; Klink, Frank

    2008-02-17

    We analyze the solar reflectance of asphalt roofing shingles that are covered with pigmented mineral roofing granules. The reflecting surface is rough, with a total area approximately twice the nominal area. We introduce a simple analytical model that relates the 'micro-reflectance' of a small surface region to the 'macro-reflectance' of the shingle. This model uses a mean field approximation to account for multiple scattering effects. The model is then used to compute the reflectance of shingles with a mixture of different colored granules, when the reflectances of the corresponding mono-color shingles are known. Simple linear averaging works well, with small corrections to linear averaging derived for highly reflective materials. Reflective base granules and reflective surface coatings aid achievement of high solar reflectance. Other factors that influence the solar reflectance are the size distribution of the granules, coverage of the asphalt substrate, and orientation of the granules as affected by rollers during fabrication.

  12. Online spectral fit tool (OSFT) for analyzing reflectance spectra

    Science.gov (United States)

    Penttilä, A.; Kohout, T.; Muinonen, K.

    2015-10-01

    We present an algorithm and its implementation for fitting continuum and absorption bands to UV/VIS/NIR reflectance spectra. The implementation is done completely in JavaScript and HTML, and will run in any modern web browser without requiring external libraries to be installed.

  13. Online Spectral Fit Tool for Analyzing Reflectance Spectra

    Science.gov (United States)

    Penttilä, A.; Kohout, T.

    2015-11-01

    The Online Spectral Fit Tool is developed for analyzing Vis-NIR spectral behavior of asteroids and meteorites. Implementation is done using JavaScript/HTML. Fitted spectra consist of spline continuum and gamma distributions for absorption bands.

  14. Measuring solar reflectance Part II: Review of practical methods

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

    2010-05-14

    A companion article explored how solar reflectance varies with surface orientation and solar position, and found that clear sky air mass 1 global horizontal (AM1GH) solar reflectance is a preferred quantity for estimating solar heat gain. In this study we show that AM1GH solar reflectance R{sub g,0} can be accurately measured with a pyranometer, a solar spectrophotometer, or an updated edition of the Solar Spectrum Reflectometer (version 6). Of primary concern are errors that result from variations in the spectral and angular distributions of incident sunlight. Neglecting shadow, background and instrument errors, the conventional pyranometer technique can measure R{sub g,0} to within 0.01 for surface slopes up to 5:12 [23{sup o}], and to within 0.02 for surface slopes up to 12:12 [45{sup o}]. An alternative pyranometer method minimizes shadow errors and can be used to measure R{sub g,0} of a surface as small as 1 m in diameter. The accuracy with which it can measure R{sub g,0} is otherwise comparable to that of the conventional pyranometer technique. A solar spectrophotometer can be used to determine R*{sub g,0}, a solar reflectance computed by averaging solar spectral reflectance weighted with AM1GH solar spectral irradiance. Neglecting instrument errors, R*{sub g,0} matches R{sub g,0} to within 0.006. The air mass 1.5 solar reflectance measured with version 5 of the Solar Spectrum Reflectometer can differ from R*{sub g,0} by as much as 0.08, but the AM1GH output of version 6 of this instrument matches R*{sub g,0} to within about 0.01.

  15. Analyzing the IAR with IRI During the Recent Solar Minimum

    Science.gov (United States)

    Ivanov, S.; Klenzing, J.; Simoes, F.

    2012-01-01

    The 2008-2009 solar minimum was deeper than any within the past century. As such, the performance of the empirical International Reference Ionosphere (IRI) model was impacted. This impact manifested as a disagreement between predicted and measured characteristic separation in frequency for a wave resonating within an Ionospheric Alfven Resonator (IAR). The predicted value of the characteristic was a factor of three lower than what was measured by the Communication/Navigation Outage Forecast System (C/NOFS). Analyzing the model performance and comparing output with measured ionospheric values showed that more than half of the inaccuracy could be explained by inaccuracies in the output of the model. The 2008-2009 solar minimum was outside of the bounds of the effectiveness of the empirical IRI model. Incorporating recent data measurements and new indices would increase the accuracy of IRI during this period.

  16. Standardization of Solar Mirror Reflectance Measurements - Round Robin Test: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Meyen, S.; Lupfert, E.; Fernandez-Garcia, A.; Kennedy, C.

    2010-10-01

    Within the SolarPaces Task III standardization activities, DLR, CIEMAT, and NREL have concentrated on optimizing the procedure to measure the reflectance of solar mirrors. From this work, the laboratories have developed a clear definition of the method and requirements needed of commercial instruments for reliable reflectance results. A round robin test was performed between the three laboratories with samples that represent all of the commercial solar mirrors currently available for concentrating solar power (CSP) applications. The results show surprisingly large differences in hemispherical reflectance (sh) of 0.007 and specular reflectance (ss) of 0.004 between the laboratories. These differences indicate the importance of minimum instrument requirements and standardized procedures. Based on these results, the optimal procedure will be formulated and validated with a new round robin test in which a better accuracy is expected. Improved instruments and reference standards are needed to reach the necessary accuracy for cost and efficiency calculations.

  17. Foveal reflection analyzer : on the spectral and directional reflectance of the retina

    OpenAIRE

    Zagers, Niels Petrus Antonius

    2004-01-01

    The first part of this thesis was on the development of a new instrument for measurement of light reflected from the retina in a living human eye. The key element is an imaging spectrograph, with its slit placed conjugate to the pupil of the eye. The instrument measures both the spectral and the directional properties of the reflected light. Model analysis of the spectral reflection yields the optical densities of ocular absorbers, e.g., the eye lens, melanin, and the macular pigment. The dir...

  18. A replaceable reflective film for solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    The 3M Company manufactures a silvered acrylic film called ECP-305 that is regarded as the preferred reflective film for use on stretched-membrane heliostats. However, ECP-305 will degrade in time, due to both corrosion of the silver layer and delamination at the film's silver-to-acrylic interface, and will eventually need to be replaced. 3M uses a very aggressive adhesive on this film, and once it is laminated, replacement is very difficult. The purpose of this investigation was the development of a replaceable reflector, a reflective film that can be easily removed and replaced. A replaceable reflector was successfully configured by laminating ECP-305 to the top surface of a smooth, dimensionally stable polymer film, with a removable adhesive applied to the underside of the polymer film. Several stages of screening and testing led to the selection of a 0.010-inch thick polycarbonate (GE 8030) as the best polymer film and a medium tack tape (3M Y-9425) was selected as the best removable adhesive. To demonstrate the feasibility of the replaceable reflector concept and to provide a real-time field test, the chosen construction was successfully applied to the 50-m{sup 2} SKI heliostat at the Central Receiver Test Facility at Sandia National Laboratories in Albuquerque. 4 refs., 13 figs., 7 tabs.

  19. Design criteria for reflection polarizers and analyzers in the vacuum ultraviolet

    Science.gov (United States)

    Hunter, W. R.

    1978-01-01

    Reflection polarizers and analyzers for the extreme UV spectral region are discussed. The conditions for optimum polarization are presented, and the polarization characteristics of a number of metal coatings, including gold and some of the platinum metals, are given. The performance of three- and four-mirror polarizers, using these metal coatings, is discussed. The properties required of a polarization analyzer are presented, and the performance of single and three- and four-reflection analyzers are discussed in terms of the optical properties of coating materials that might be useful for analyzers.

  20. Discussion on common errors in analyzing sea level accelerations, solar trends and global warming

    CERN Document Server

    Scafetta, Nicola

    2013-01-01

    Errors in applying regression models and wavelet filters used to analyze geophysical signals are discussed: (1) multidecadal natural oscillations (e.g. the quasi 60-year Atlantic Multidecadal Oscillation (AMO), North Atlantic Oscillation (NAO) and Pacific Decadal Oscillation (PDO)) need to be taken into account for properly quantifying anomalous accelerations in tide gauge records such as in New York City; (2) uncertainties and multicollinearity among climate forcing functions prevent a proper evaluation of the solar contribution to the 20th century global surface temperature warming using overloaded linear regression models during the 1900-2000 period alone; (3) when periodic wavelet filters, which require that a record is pre-processed with a reflection methodology, are improperly applied to decompose non-stationary solar and climatic time series, Gibbs boundary artifacts emerge yielding misleading physical interpretations. By correcting these errors and using optimized regression models that reduce multico...

  1. Suomi NPP VIIRS Reflective Solar Bands Operational Calibration Reprocessing

    Directory of Open Access Journals (Sweden)

    Slawomir Blonski

    2015-12-01

    Full Text Available Radiometric calibration coefficients for the VIIRS (Visible Infrared Imaging Radiometer Suite reflective solar bands have been reprocessed from the beginning of the Suomi NPP (National Polar-orbiting Partnership mission until present. An automated calibration procedure, implemented in the NOAA (National Oceanic and Atmospheric Administration JPSS (Joint Polar Satellite System operational data production system, was applied to reprocess onboard solar calibration data and solar diffuser degradation measurements. The latest processing parameters from the operational system were used to include corrected solar vectors, optimized directional dependence of attenuation screens transmittance and solar diffuser reflectance, updated prelaunch calibration coefficients without an offset term, and optimized Robust Holt-Winters filter parameters. The parameters were consistently used to generate a complete set of the radiometric calibration coefficients for the entire duration of the Suomi NPP mission. The reprocessing has demonstrated that the automated calibration procedure can be successfully applied to all solar measurements acquired from the beginning of the mission until the full deployment of the automated procedure in the operational processing system. The reprocessed calibration coefficients can be further used to reprocess VIIRS SDR (Sensor Data Record and other data products. The reprocessing has also demonstrated how the automated calibration procedure can be used during activation of the VIIRS instruments on the future JPSS satellites.

  2. Improved analysis of solar signals for differential reflectivity monitoring

    Science.gov (United States)

    Huuskonen, Asko; Kurri, Mikko; Holleman, Iwan

    2016-07-01

    The method for the daily monitoring of the differential reflectivity bias for polarimetric weather radars is developed further. Improved quality control is applied to the solar signals detected during the operational scanning of the radar, which efficiently removes rain and clutter-contaminated gates occurring in the solar hits. The simultaneous reflectivity data are used as a proxy to determine which data points are to be removed. A number of analysis methods to determine the differential reflectivity bias are compared, and methods based on surface fitting are found superior to simple averaging. A separate fit to the reflectivity of the horizontal and vertical polarization channels is recommended because of stability. Separate fitting also provides, in addition to the differential reflectivity bias, the pointing difference of the polarization channels. Data from the Finnish weather radar network show that the pointing difference is less than 0.02° and that the differential reflectivity bias is stable and determined to better than 0.04 dB. The results are compared to those from measurements at vertical incidence, which allows us to determine the total differential reflectivity bias including the differential receiver bias and the transmitter bias.

  3. Implementation of solar-reflective surfaces: Materials and utility programs

    Energy Technology Data Exchange (ETDEWEB)

    Bretz, S.; Akbari, H.; Rosenfeld, A.; Taha, H.

    1992-06-01

    This report focuses on implementation issues for using solar-reflective surfaces to cool urban heat islands, with specific examples for Sacramento, California. Advantages of solar-reflective surfaces for reducing energy use are: (1) they are cost-effective if albedo is increased during routine maintenance; (2) the energy savings coincide with peak demand for power; (3) there are positive effects on environmental quality; and (4) the white materials have a long service life. Important considerations when choosing materials for mitigating heat islands are identified as albedo, emissivity, durability, cost, pollution and appearance. There is a potential for increasing urban albedo in Sacramento by an additional 18%. Of residential roofs, we estimate that asphalt shingle and modified bitumen cover the largest area, and that built-up roofing and modified bitumen cover the largest area of commercial buildings. For all of these roof types, albedo may be increased at the time of re-roofing without any additional cost. When a roof is repaired, a solar-reflective roof coating may be applied to significantly increase albedo and extend the life of the root Although a coating may be cost-effective if applied to a new roof following installation or to an older roof following repair, it is not cost-effective if the coating is applied only to save energy. Solar-reflective pavement may be cost-effective if the albedo change is included in the routine resurfacing schedule. Cost-effective options for producing light-colored pavement may include: (1) asphalt concrete, if white aggregate is locally available; (2) concrete overlays; and (3) newly developed white binders and aggregate. Another option may be hot-rolled asphalt, with white chippings. Utilities could promote solar-reflective surfaces through advertisement, educational programs and cost-sharing of road resurfacing.

  4. Research Needs: Glass Solar Reflectance and Vinyl Siding

    Energy Technology Data Exchange (ETDEWEB)

    Hart, Robert; Curcija, Charlie; Arasteh, Dariush; Goudey, Howdy; Kohler, Christian; Selkowitz, Stephen

    2011-07-07

    The subject of glass solar reflectance and its contribution to permanent vinyl siding distortion has not been extensively studied, and some phenomena are not yet well understood. This white paper presents what is known regarding the issue and identifies where more research is needed. Three primary topics are discussed: environmental factors that control the transfer of heat to and from the siding surface; vinyl siding properties that may affect heat build-up and permanent distortion; and factors that determine the properties of reflected solar radiation from glass surfaces, including insulating window glass. Further research is needed to fully characterize the conditions associated with siding distortion, the scope of the problem, physical properties of vinyl siding, insulating window glass reflection characteristics, and possible mitigation or prevention strategies.

  5. Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

    2010-05-14

    Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective 'cool colored' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland U.S. latitudes, this metric RE891BN can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {le} 5:12 [23{sup o}]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool-roof net energy savings by as much as 23%. We define clear-sky air mass one global horizontal ('AM1GH') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer.

  6. Earth Reflected Solar Radiation Input to Spherical Satellites

    Science.gov (United States)

    Cunningham, F. G.

    1961-01-01

    A general calculation is given for the earth's albedo input to a spherical satellite, with the assumption that the earth can be considered a diffusely reflecting sphere. The results are presented in general form so that appropriate values for the solar constant and albedo of the earth can be used as more accurate values become available. The results are also presented graphically; the incident power is determined on the assumption that the mean solar constant is 1.353 x 10( exp 6) erg/(sq cm.sec) and the albedo of the earth is 0.34.

  7. Contaminated Solar Array Handrail Samples Retrieved From Mir Analyzed

    Science.gov (United States)

    deGroh, Kim K.; McCue, Terry R.

    2000-01-01

    In January 1998 during the shuttle STS 89 mission, an eight-section Russian solar array panel was retrieved after more than 10 years of exposure to the orbital space environment on Mir. The array was deployed June 16, 1987, and removed on November 3, 1997. It had been actively used as a source of electrical power for 8 years. This operational array had been located on the Mir core module, located directly above the Kvant-2 module. Its retrieval provided a unique opportunity to study the effects of the low-Earth-orbit environment on a functional solar array. The intact solar array underwent scientific inspections and preliminary tests by a joint team of U.S. and Russian investigators to evaluate the effects of long-term space exposure. Upon initial examination, significant contamination was observed over most components of the array. One panel, panel 8, was provided to the U.S. scientists for further evaluation. As part of the U.S. investigations, two solar array handrail samples from panel 8 were evaluated for contamination at the NASA Glenn Research Center at Lewis Field. One is a section of a rigid handrail, and the other is a section of woven fabric tape that was overwrapped around a flexible handhold. Both the flexible handhold woven fabric and the rigid handrail were significantly darkened after 10 years of space exposure. They were evaluated with optical microscopy, field emission scanning electron microscopy (FESEM), and energy-dispersive spectroscopy. Solar absorptance and room-temperature emittance values also were obtained. The returned contaminated solar array segment is very similar in design to the solar arrays being supplied by the Russians for the International Space Station. Therefore, it was desirable to determine what the contaminants on various surfaces are and what the sources of the contamination were.

  8. Reflectance of metallic indium for solar energy applications

    Science.gov (United States)

    Bouquet, F. L.; Hasegawa, T.

    1984-01-01

    An investigation has been conducted in order to compile quantitative data on the reflective properties of metallic indium. The fabricated samples were of sufficiently high quality that differences from similar second-surface silvered mirrors were not apparent to the human eye. Three second-surface mirror samples were prepared by means of vacuum deposition techniques, yielding indium thicknesses of approximately 1000 A. Both hemispherical and specular measurements were made. It is concluded that metallic indium possesses a sufficiently high specular reflectance to be potentially useful in many solar energy applications.

  9. Summary report of the Solar Reflective Materials Technology Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M.A.; Ault, L.E.

    1978-10-01

    The Solar Reflective Materials Technology Workshop sponsored by the Department of Energy and organized by the Pacific Northwest Laboratory and the Solar Energy Research Institute was held on March 28--30, 1978, in Denver, Colorado. The two and one-half day seminar/workshop was attended by over 95 people representing some 60 private companies and government laboratories. The purpose of the workshop was to assess the ''state-of-the-art'' of solar reflector materials technology, define current mirror design requirements, and make recommendations to DOE for future research and development efforts. The reflector materials are defined for the purpose of this workshop as including all the materials which make up the reflector structure including the actual reflecting surface, the protective coatings, and the support substrate. The reflective surface includes metals, metallic films, metallic alloys, and dielectric or ceramic stacks. The protective coatings, which can be applied to both the front and back of the reflective surface, include such materials as polymer paints and films as well as inorganic coatings such as SiO, MgF/sub 2/ and thin glass. Mirror support structures which have been considered include polymer foams, cellular glass, aluminum honeycomb, wood and paper products, and fiberglass and epoxy composites. The authors of the invited papers were asked to emphasize one or more of four basic areas. These topics included: the requirements and properties for reflector materials, the testing procedures used to evaluate the materials, the results of environmental tests performed on some of the materials, and the actual field experience of solar concentrator structures. Acknowledging that the most severe applications for reflector materials result from high concentration ratio or central receiver concepts, the majority of the speakers addressed specific problems dealing with these concepts. (WHK)

  10. Solarscope, a method to analyze solar ambient application to the solar comparison of three streets

    Energy Technology Data Exchange (ETDEWEB)

    Follut, Dominique [Nantes (France)

    2000-07-01

    Amongst the various studies of urban forms, many are concerned with typo-morphological aspects, possibly combined with historical factors. Another way to analyze urban forms may consist in examining them as closely related to various environmental factors. This paper examines the incidence of sunlight on urban built-up forms and introduces the notion of Solarscope and the sun effects in relation to the morphology. Solarscope is a method that integrated human being, its position in the urban site and enables an environmental interpretation of the results obtained from the various numerical simulations. Only the solar part of the method will be presented here. This method aims to analyze results of simulation through specific descriptors relative to the spatial position of an observer. This is a new way to analyze the physical data of the urban space by positioning into the urban scene a user of this space that would observe the built environment. This method allows therefore to constitute a cartography of the urban void and not only the facets elements of the buildings and ground. Introducing the observer, it is therefore more a cartography of the perceived space than a cartography of a phenomenon in a space. [Spanish] Entre los diversos estudios de formas urbanas, muchas estan enfocadas a aspectos tipo-morfologicos, posiblemente combinados con factores historicos. Otra manera de analizar formas urbanas puede consistir en examinarlos como relacionadas muy de cerca con varios factores ambientales. Este articulo examina la incidencia de luz solar sobre formas urbanas integradas e introduce la nocion de Solarscope (Ambito Solar) y los efectos del sol con relacion a la morfologia. El Solarscope es un metodo que integra al ser humano, su posicion en el espacio urbano y posibilita una interpretacion ambiental de los resultados obtenidos de diversas simulaciones numericas. Solo la parte solar del metodo se presenta aqui. Este metodo se orienta a analizar los resultados de

  11. Analysis of Cumulus Solar Irradiance Reflectance (CSIR) Events

    Science.gov (United States)

    Laird, John L.; Harshvardham

    1996-01-01

    Clouds are extremely important with regard to the transfer of solar radiation at the earth's surface. This study investigates Cumulus Solar Irradiance Reflection (CSIR) using ground-based pyranometers. CSIR events are short-term increases in solar radiation observed at the surface as a result of reflection off the sides of convective clouds. When sun-cloud observer geometry is favorable, these occurrences produce characteristic spikes in the pyranometer traces and solar irradiance values may exceed expected clear-sky values. Ultraviolet CSIR events were investigated during the summer of 1995 using Yankee Environmental Systems UVA-1 and UVB-1 pyranometers. Observed data were compared to clear-sky curves which were generated using a third degree polynomial best-fit line technique. Periods during which the observed data exceeded this clear-sky curve were identified as CSIR events. The magnitude of a CSIR event was determined by two different quantitative calculations. The MAC (magnitude above clear-sky) is an absolute measure of the difference between the observed and clear-sky irradiances. Maximum MAC values of 3.4 Wm(exp -2) and 0.069 Wm(exp -2) were observed at the UV-A and UV-B wavelengths, respectively. The second calculation determined the percentage above clear-sky (PAC) which indicated the relative magnitude of a CSIR event. Maximum UV-A and UV-B PAC magnitudes of 10.1% and 7.8%, respectively, were observed during the study. Also of interest was the duration of the CSIR events which is a function of sun-cloud-sensor geometry and the speed of cloud propagation over the measuring site. In both the UV-A and UV-B wavelengths, significant CSIR durations of up to 30 minutes were observed.

  12. Analysis of cumulus solar irradiance reflectance (CSIR) events

    Science.gov (United States)

    Laird, John L.; Harshvardhan

    Clouds are extremely important with regard to the transfer of solar radiation at Earth's surface. This study investigates Cumulus Solar Irradiance Reflection (CSIR) using ground-based pyranometers. CSIR events are short-term increases in solar radiation observed at the surface as a result of reflection off the sides of convective clouds. When Sun-cloud observer geometry is favorable, these occurrences produce characteristic spikes in the pyranometer traces and solar irradiance values may exceed expected clear-sky values. Ultraviolet CSIR events were investigated during the summer of 1995 using UVA and UVB pyranometers. Observed data were compared to clear-sky curves which were generated using a third degree polynomial best-fit line technique. Periods during which the observed data exceeded this clear-sky curve were identified as CSIR events. The magnitude of a CSIR event was determined by two different quantitative calculations. The MAC (magnitude above clear-sky) is an absolute measure of the difference between the observed and clear-sky irradiances. Maximum MAC values of 3.4 Win -2 and 0.0169 Wm -2 were observed at the UV-A and UV-B wavelengths, respectively. The second calculation determined the percentage above clear-sky (PAC) which indicated the relative magnitude of a CSIR event. Maximum UV-A and UV-B PAC magnitudes of 10.1% and 7.8%, respectively, were observed during the study. Also of interest was the duration of the CSIR events which is a function of Sun-cloud-sensor geometry and the speed of cloud propagation over the measuring site. In both the UV-A and UV-B wavelengths, significant CSIR durations of up to 30 minutes were observed. C 1997 Elsevier Science B.V.

  13. Degradation nonuniformity in the solar diffuser bidirectional reflectance distribution function.

    Science.gov (United States)

    Sun, Junqiang; Chu, Mike; Wang, Menghua

    2016-08-01

    The assumption of angular dependence stability of the solar diffuser (SD) throughout degradation is critical to the on-orbit calibration of the reflective solar bands (RSBs) in many satellite sensors. Recent evidence has pointed to the contrary, and in this work, we present a thorough investigative effort into the angular dependence of the SD degradation for the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite and for the twin Moderate-resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua spacecrafts. One common key step in the RSB calibration is the use of the SD degradation performance measured by an accompanying solar diffuser stability monitor (SDSM) as a valid substitute for the SD degradation factor in the direction of the RSB view. If SD degradations between these two respective directions do not maintain the same relative relationship over time, then the unmitigated use of the SDSM-measured SD degradation factor in the RSB calibration calculation will generate bias, and consequently, long-term drift in derived science products. We exploit the available history of the on-orbit calibration events to examine the response of the SDSM and the RSB detectors to the incident illumination reflecting off SD versus solar declination angle and show that the angular dependency, particularly at short wavelengths, evolves with respect to time. The generalized and the decisive conclusion is that the bidirectional reflectance distribution function (BRDF) of the SD degrades nonuniformly with respect to both incident and outgoing directions. Thus, the SDSM-based measurements provide SD degradation factors that are biased relative to the RSB view direction with respect to the SD. The analysis also reveals additional interesting phenomena, for example, the sharp behavioral change in the evolving angular dependence observed in Terra MODIS and SNPP VIIRS. For SNPP VIIRS the mitigation for this

  14. Improvement in greenhouse solar drying using inclined north wall reflection

    Energy Technology Data Exchange (ETDEWEB)

    Sethi, V.P. [Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana 141004, Punjab (India); Arora, Sadhna [Department of Processing and Food Engineering, Punjab Agricultural University, Ludhiana 141004, Punjab (India)

    2009-09-15

    A conventional greenhouse solar dryer of 6 m{sup 2} x 4 m{sup 2} floor area (east-west orientation) was improved for faster drying using inclined north wall reflection (INWR) under natural as well as forced convection mode. To increase the solar radiation availability onto the product (to be dried) during extreme summer months, a temporary inclined wall covered with aluminized reflector sheet (of 50 {mu}m thickness and reflectance 0.93) was raised inside the greenhouse just in front of the vertical transparent north wall. By doing so, product fully received the reflected beam radiation (which otherwise leaves through the north wall) in addition to the direct total solar radiation available on the horizontal surface during different hours of drying. The increment in total solar radiation input enhanced the drying rate of the product by increasing the inside air and crop temperature of the dryer. Inclination angle of the reflective north wall with vertical ({beta}) was optimized for various selective widths of the tray W (1.5, 2, 2.5 and 3 m) and for different realistic heights of existing vertical north wall (h) at 25 N, 30 N and 35 N latitudes (hot climatic zones). Experimental performance of the improved dryer was tested during the month of May 2008 at Ludhiana (30.56 N) climatic conditions, India by drying bitter gourd (Momordica charantia Linn) slices. Results showed that by using INWR under natural convection mode of drying, greenhouse air and crop temperature increased by 1-6.7 C and 1-4 C, respectively, during different drying hours as compared to, when INWR was not used and saved 13.13% of the total drying time. By using INWR under forced convection mode of drying, greenhouse air and crop temperature increased by 1-4.5 C and 1-3 C, respectively, during different drying hours as compared to, when INWR was not used and saved 16.67% of the total drying time. (author)

  15. A word-count approach to analyze linguistic patterns in the reflective writings of medical students

    Directory of Open Access Journals (Sweden)

    Chi-Wei Lin

    2016-02-01

    Full Text Available Background: Teaching reflection and administering reflective writing assignments to students are widely practiced and discussed in medical education and health professional education. However, little is known about how medical students use language to construct their narratives. Exploring students’ linguistic patterns in their reflective writings can facilitate understanding the scope and facets of their reflections and their representational or communication approaches to share their experiences. Moreover, research findings regarding gender differences in language use are inconsistent. Therefore, we attempted to examine how females and males differ in their use of words in reflective writing within our research circumstance to detect the unique and gender-specific approaches to learning and their applications. Methods: We analyzed the linguistic profiles of psychological process categories in the reflective writings of medical students and examined the difference in word usage between male and female medical students. During the first year of a clinical rotation, 60 fifth-year medical students wrote reflective narratives regarding pediatric patients and the psychosocial challenges faced by the patients and their family members. The narratives were analyzed using the Chinese version of Linguistic Inquiry and Word Count (CLIWC, a text analysis software program. Multivariate procedures were applied for statistical analysis. Results: Cognitive words were most pervasive, averaging 22.16%, whereas perceptual words (2.86% were least pervasive. Female students used more words related to positive emotions and sadness than did male students. The male students exceeded the female students only in the space category. The major limitation of this study is that CLIWC cannot directly acquire contextual text meanings; therefore, depending on the research topic, further qualitative study of the given texts might be necessary. Conclusions: To enhance students

  16. Analyzing the Effectiveness and Practicality of Reflective Approach in Teaching and Learning

    Institute of Scientific and Technical Information of China (English)

    广东科技学院 广东 东莞 523083

    2013-01-01

    This essay aims to analyze the ef ectiveness of reflective practice in the teaching and learning of English and to examine the practicality of this approach in the current classroom. Firstly, some problems of traditional teaching were examined, and limitations of reflective practice in teaching were presented when stating its conductive advantages. Then the paper stated the ef ectiveness of reflective practice in language classes, such as active reaction from students and the ability of problem solving, and discussed the practicality between reflective teaching and learning through adopting reflective practice. Reflective practice, an important approach in improving the ef iciency of English teaching as a foreign language and making students develop their understanding and critical thinking skil s, wil be wel-developed in the process of teaching and learning.%本文主要分析反实践教学法在目前教学当中的有效性和实践性。首先,通过对传统教学法弱点和反实践教学法限制性的分析比较,得出反实践教学法在教学和学习当中具有传导性优势。然后阐述了反实践教学法在语言学习上的有效性,例如:学生的积极反映和解决问题能力,最后讨论了在教学和学习中它的实践性。反实践教学法不仅在提高英语教学效率上起着重要的作用,而且在培养学生的思考能力和批判性思维上也会得到更好的发展。

  17. MODIS reflective solar bands calibration improvements in Collection 6

    Science.gov (United States)

    Sun, Junqiang; Angal, Amit; Xiong, Xiaoxiong; Chen, Hongda; Geng, Xu; Wu, Aisheng; Choi, Taeyoung; Chu, Mike

    2012-11-01

    Since launch, Terra and Aqua MODIS have performed more than 12 and 10 years of scientific measurements of the Earth's surface. MODIS has 36 spectral bands, among which 20 are Reflective Solar Bands (RSB), covering a spectral range from 0.41 μm to 2.1 μm. MODIS was developed with stringent requirements for calibration and uncertainty and is equipped with a set of on-board calibrators (OBC) that facilitate a constant monitoring and update of its on-orbit calibration coefficients. The RSB are calibrated on-orbit using a Solar Diffuser (SD) and a Solar Diffuser Stability Monitor (SDSM), with help from the lunar observations via a Space View (SV) port and an onboard Spectroradiometric Calibration Assembly (SRCA). The algorithms to accurately characterize the sensor's gain change and the on-orbit change in the response versus scan-angle (RVS) have been applied to improve the quality of the Earth-view measurements. Various improvements to the calibration algorithms have been incorporated since launch and the following paper will discuss the calibration algorithms and enhancements developed for MODIS Collection 6 (C6) processing. In addition, to supplement the measurements from the on-board calibrators, pseudo-invariant desert targets are also used to track the on-orbit response change for selective RSB. Discussions of the on-orbit calibration uncertainty and the Level 1B (L1B) Uncertainty index (UI) product are also included. A comprehensive assessment of the impact on the L1B product in comparison to Collection 5 (C5) is also discussed. Significant improvements are observed in the case of VIS bands wherein the long-term bias observed in C5 products is eliminated to provide a more accurate radiometric product.

  18. Analyzing the Impact of Solar Power on Multi-Hourly Thermal Generator Ramping

    Energy Technology Data Exchange (ETDEWEB)

    Rosenkranz, Joshua-Benedict; Brancucci Martinez-Anido, Carlo; Hodge, Bri-Mathias

    2016-04-08

    Solar power generation, unlike conventional forms of electricity generation, has higher variability and uncertainty in its output because solar plant output is strongly impacted by weather. As the penetration rate of solar capacity increases, grid operators are increasingly concerned about accommodating the increased variability and uncertainty that solar power provides. This paper illustrates the impacts of increasing solar power penetration on the ramping of conventional electricity generators by simulating the operation of the Independent System Operator -- New England power system. A production cost model was used to simulate the power system under five different scenarios, one without solar power and four with increasing solar power penetrations up to 18%, in terms of annual energy. The impact of solar power is analyzed on six different temporal intervals, including hourly and multi-hourly (2- to 6-hour) ramping. The results show how the integration of solar power increases the 1- to 6-hour ramping events of the net load (electric load minus solar power). The study also analyzes the impact of solar power on the distribution of multi-hourly ramping events of fossil-fueled generators and shows increasing 1- to 6-hour ramping events for all different generators. Generators with higher ramp rates such as gas and oil turbine and internal combustion engine generators increased their ramping events by 200% to 280%. For other generator types--including gas combined-cycle generators, coal steam turbine generators, and gas and oil steam turbine generators--more and higher ramping events occurred as well for higher solar power penetration levels.

  19. A Low Cost Shading Analyzer and Site Evaluator Design to Determine Solar Power System Installation Area

    Directory of Open Access Journals (Sweden)

    Selami Kesler

    2015-01-01

    Full Text Available Shading analyzer systems are necessary for selecting the most suitable installation site to sustain enough solar power. Afterwards, changes in solar data throughout the year must be evaluated along with the identification of obstructions surrounding the installation site in order to analyze shading effects on productivity of the solar power system. In this study, the shading analysis tools are introduced briefly, and a new and different device is developed and explained to analyze shading effect of the environmental obstruction on the site on which the solar power system will be established. Thus, exposure duration of the PV panels to the sunlight can be measured effectively. The device is explained with an application on the installation area selected as a pilot site, Denizli, in Turkey.

  20. Analyzing Reflections in Service Learning to Promote Personal Growth and Community Self-Efficacy

    Science.gov (United States)

    Sanders, Martha J.; Van Oss, Tracy; McGeary, Signian

    2016-01-01

    The use of structured reflections for promoting personal understanding and community self-efficacy was examined in 65 occupational therapy college students in a service learning course. Students in the experimental group wrote structured reflections throughout the semester while students in the control groups used non-structured reflections.…

  1. Backscatter of hard X-rays in the solar atmosphere. [Calculating the reflectance of solar x ray emission

    Science.gov (United States)

    Bai, T.; Ramaty, R.

    1977-01-01

    The solar photosphere backscatters a substantial fraction of the hard X rays from solar flares incident upon it. This reflection was studied using a Monte Carlo simulation which takes into account Compton scattering and photo-electric absorption. Both isotropic and anisotropic X ray sources are considered. The bremsstrahlung from an anisotropic distribution of electrons are evaluated. By taking the reflection into account, the inconsistency is removed between recent observational data regarding the center-to-limb variation of solar X ray emission and the predictions of models in which accelerated electrons are moving down toward the photosphere.

  2. Estimation of reflection spectra for different type antireflection coatings to silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V.; Martirosyan, Kh. [Dept. Phys. Semicond. and Microelectronics, Yerevan State Univ., Yerevan (Armenia)

    2004-07-01

    In this letter, we simulate the cases of different types antireflection coatings made from porous silicon, dielectric mirrors, silicon oxynitride and silicon carbide to explore antireflection coating having advanced properties in solar cells. Using the optical matrix approach method, we calculate the reflectance of these structures. Comparing with the reflectance obtained for other antireflection coatings, we find a much lower reflectance in the UV-, visible- and IR-regions of the solar spectrum for these antireflection coatings, indicating the strong interest of the letters in solar cell applications. (orig.)

  3. Optimization of the Nano-Dust Analyzer (NDA) for operation under solar UV illumination

    Science.gov (United States)

    O`Brien, L.; Grün, E.; Sternovsky, Z.

    2015-12-01

    The performance of the Nano-Dust Analyzer (NDA) instrument is analyzed for close pointing to the Sun, finding the optimal field-of-view (FOV), arrangement of internal baffles and measurement requirements. The laboratory version of the NDA instrument was recently developed (O'Brien et al., 2014) for the detection and elemental composition analysis of nano-dust particles. These particles are generated near the Sun by the collisional breakup of interplanetary dust particles (IDP), and delivered to Earth's orbit through interaction with the magnetic field of the expanding solar wind plasma. NDA is operating on the basis of impact ionization of the particle and collecting the generated ions in a time-of-flight fashion. The challenge in the measurement is that nano-dust particles arrive from a direction close to that of the Sun and thus the instrument is exposed to intense ultraviolet (UV) radiation. The performed optical ray-tracing analysis shows that it is possible to suppress the number of UV photons scattering into NDA's ion detector to levels that allow both high signal-to-noise ratio measurements, and long-term instrument operation. Analysis results show that by avoiding direct illumination of the target, the photon flux reaching the detector is reduced by a factor of about 103. Furthermore, by avoiding the target and also implementing a low-reflective coating, as well as an optimized instrument geometry consisting of an internal baffle system and a conical detector housing, the photon flux can be reduced by a factor of 106, bringing it well below the operation requirement. The instrument's FOV is optimized for the detection of nano-dust particles, while excluding the Sun. With the Sun in the FOV, the instrument can operate with reduced sensitivity and for a limited duration. The NDA instrument is suitable for future space missions to provide the unambiguous detection of nano-dust particles, to understand the conditions in the inner heliosphere and its temporal

  4. Collecting, analyzing and archiving of ground based infrared solar spectra obtained from several locations

    Science.gov (United States)

    Murcray, David G.; Murcray, Frank J.; Goldman, Aaron; Mcelroy, Charles T.; Chu, William P.; Rinsland, Curtis P.; Woods, Peter; Matthews, W. A.; Johnston, P. V.

    1990-01-01

    The infrared solar spectrum as observed from the ground under high resolution contains thousands of absorption lines. The majority of these lines are due to compounds that are present in the Earth's atmosphere. Ground based infrared solar spectra contain information concerning the composition of the atmosphere at the time the spectra were obtained. The objective of this program is to record solar spectra from various ground locations, and to analyze and archive these spectra. The analysis consists of determining, for as many of the absorption lines as possible, the molecular species responsible for the absorption, and to verify that current models of infrared transmission match the observed spectra. Archiving is an important part of the program, since a number of the features in the spectra have not been identified. At some later time, when the features are identified, it will be possible to determine the amount of that compound that was present in the atmosphere at the time the spectrum was taken.

  5. Applying measured reflection from the ground to simulations of thermal perfromance of solar collectors

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon

    2009-01-01

    Solar radiation on tilted and vertical surfaces in the Arctic is, in large parts of the year, strongly influenced by reflection from snow. In connection with planning and optimization of energy efficient buildings and solar energy systems in the Arctic, it is important to have an accurate...... representation of the reflection from the ground. In this study a more accurate description of the albedo is obtained based on detailed measurements from a solar hat, installed at ASIAQ’s climate station in Sisimiut, Greenland. The solar hat measures the global radiation on horizontal, the total radiation on...... vertical surfaces facing north, south, east and west, and radiation reflected from the ground on vertical surfaces facing north, south, east and west. Based on measured data from 2004-2007 the albedo is determined for each month of the year as a function of the difference between the solar azimuth and the...

  6. Development of Advanced Anti-Reflection Coatings for High Performance Solar Energy Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MicroLink and its subcontractor Magnolia Solar will develop and demonstrate advanced anti-reflection coating (ARC) designs that will provide a better broadband and...

  7. Development of Advanced Anti-Reflection Coatings for High Performance Solar Energy Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MicroLink Devices will increase the efficiency of multi-junction solar cells by designing and demonstrating advanced anti-reflection coatings (ARCs) that will...

  8. Laser processing of solar cells with anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Gabriel; Smith, David D.; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

    2016-02-16

    Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

  9. Thin silicon based films on glass analyzed by laser modulated optical reflectance

    International Nuclear Information System (INIS)

    Amorphous and microcrystalline Si-based films deposited by magnetron sputtering on glass have been characterized with respect to their electronic and thermal properties by the laser-modulated optical reflectance method. Using a modulated pump beam (Ar+ laser) with photon energies above the band gap, charge carrier waves and thermal waves are simultaneously excited in the semi-conducting film. The non-contact laser modulated optical reflectance method gives direct information on the electronic properties and can thus be used to study and optimize the growth conditions of semiconductor films. (Authors)

  10. Infrared-Reflective Coating on Fused Silica for a Solar High-Temperature Receiver

    OpenAIRE

    Röger, Marc; Rickers, Christoph; Uhlig, Ralf; Neumann, Frank; Polenzky, Christina

    2007-01-01

    In concentrating solar power, high-temperature solar receivers can provide heat to highly efficient cycles for electricity or chemical production. Excessive heating of the fused-silica window and the resulting recrystallization are major problems of high-temperature receivers using windows. Excessive window temperatures can be avoided by applying an infrared-reflective solar-transparent coating on the fused-silica window inside. Both glass temperatures and receiver losses can be reduced. An i...

  11. An analytical model for analyzing the current-voltage characteristics of bulk heterojunction organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Arnab, Salman M.; Kabir, M. Z., E-mail: kabir@encs.concordia.ca [Department of Electrical and Computer Engineering, Concordia University, 1455 Blvd. de Maisonneuve West, Montreal, Quebec H3G 1M8 (Canada)

    2014-01-21

    An analytical model for analyzing the current-voltage (J-V) characteristics of bulk heterojunction (BHJ) organic solar cells is developed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun's model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The charge carrier concentrations and hence the photocurrent are calculated by solving the carrier continuity equation for both holes and electrons in the organic layer. The overall load current is calculated considering the actual solar spectrum and voltage dependent forward dark current. The model is verified by published experimental results. The efficiency of the P3HT:PCBM based solar cells critically depends on the dissociation of bound EHPs. On the other hand, cells made of a blend of the conjugated polymer (PCDTBT) with the soluble fullerene derivative (PCBM) show nearly unity dissociation efficiency, and their cell efficiency strongly depends on the charge collection efficiency. The effects of carrier lifetimes on the performance of PCDTBT solar cells have also been studied. The model is also used to investigate the effect of titanium oxide (TiO{sub x}) layer (at the back contact) on the J-V characteristics of PCDTBT solar cells. The results of this paper indicate that improvement of charge carrier transport in PCDTBT:PCBM blend and dissociation of bound EHPs in P3HT:PCBM blend are extremely important to increase the power conversion efficiency of the respective BHJ solar cells.

  12. An analytical model for analyzing the current-voltage characteristics of bulk heterojunction organic solar cells

    International Nuclear Information System (INIS)

    An analytical model for analyzing the current-voltage (J-V) characteristics of bulk heterojunction (BHJ) organic solar cells is developed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun's model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The charge carrier concentrations and hence the photocurrent are calculated by solving the carrier continuity equation for both holes and electrons in the organic layer. The overall load current is calculated considering the actual solar spectrum and voltage dependent forward dark current. The model is verified by published experimental results. The efficiency of the P3HT:PCBM based solar cells critically depends on the dissociation of bound EHPs. On the other hand, cells made of a blend of the conjugated polymer (PCDTBT) with the soluble fullerene derivative (PCBM) show nearly unity dissociation efficiency, and their cell efficiency strongly depends on the charge collection efficiency. The effects of carrier lifetimes on the performance of PCDTBT solar cells have also been studied. The model is also used to investigate the effect of titanium oxide (TiOx) layer (at the back contact) on the J-V characteristics of PCDTBT solar cells. The results of this paper indicate that improvement of charge carrier transport in PCDTBT:PCBM blend and dissociation of bound EHPs in P3HT:PCBM blend are extremely important to increase the power conversion efficiency of the respective BHJ solar cells

  13. Influence of Reflectivity and Cloud Cover on the Optimal TiltAngle of Solar Panels

    Directory of Open Access Journals (Sweden)

    David J. Torres

    2015-09-01

    Full Text Available Determining the optimum angle for a solar panel is important if tracking systems are not used and a tilt angle remains constant. This article determines the sensitivity of the optimum angle to surface reflectivity at different latitudes using a mathematical model that accounts for direct, diffuse and reflected radiation. A quadratic correlation is also developed to compute the optimal angle and maximum energy as a function of latitude and reflectivity. We also seek to determine how sensitive the optimal tilt angle is to cloud cover using the 35° latitude of the Prosperity solar facility in Albuquerque, NM.

  14. Performance Analysis of the Nano Dust Analyzer Under Solar UV Illumination

    Science.gov (United States)

    O'Brien, L. E.; Gruen, E.; Sternovsky, Z.

    2014-12-01

    The Nano Dust Analyzer (NDA) is a linear time-of-flight mass analyzer developed to measure the distribution and elemental composition of nanometer-sized dust particles originating in the inner Heliosphere. The temporal variability of the flux and angular distribution is governed by the complex interaction with the interplanetary magnetic field within 1 AU and provides the means also to learn about solar wind conditions. As part of a heliospheric mission, measurements made by the NDA will determine the size-dependent flux of nano-dust and its variations, it will characterize the composition of nano-dust, and may determine their source processes. The nano-dust particles arrive at 1 AU approximately from the direction of the Sun, thus, the NDA is designed specifically to operate while being exposed directly to solar UV radiation. Here, we report on the performance analysis of the NDA under UV illumination. Solar UV radiation is most likely the largest source of noise for the instrument. A fraction of incident photons will scatter into the ion detector and generate background noise, reducing the instrument's sensitivity. The detailed modeling is conducted using a commercial ray-tracing program. The instrument's performance while exposed to UV radiation is optimized in terms of instrument geometry and surface materials/optical properties, and the requirements on all optical surfaces that are necessary to reduce the effect of UV to the required level are defined and presented here.

  15. Influence of Reflectivity and Cloud Cover on the Optimal TiltAngle of Solar Panels

    OpenAIRE

    Torres, David J.; Jorge Crichigno

    2015-01-01

    Determining the optimum angle for a solar panel is important if tracking systems are not used and a tilt angle remains constant. This article determines the sensitivity of the optimum angle to surface reflectivity at different latitudes using a mathematical model that accounts for direct, diffuse and reflected radiation. A quadratic correlation is also developed to compute the optimal angle and maximum energy as a function of latitude and reflectivity. We also seek to determine how sensitive ...

  16. Photochromic And Thermochromic Pigments For Solar Absorbing-Reflecting Coatings

    Science.gov (United States)

    Novinson, Thomas

    1987-11-01

    Both photochromic and thermochromic compounds were synthesized and physical measurements were made to determine coefficients of relectance, absorbance and emission. The most interesting group of thermochromic compounds are related to silver tctraiodomercurate and the most interesting photochromic compounds are substituted benzoindolinopyrospirans. The synthesis and optical reflectance and absorbance properties of other classes of compounds are also reported.

  17. Reflection and transmission of solar light by clouds: asymptotic theory

    Directory of Open Access Journals (Sweden)

    A. A. Kokhanovsky

    2006-01-01

    Full Text Available The authors introduce a radiative transfer model CLOUD for reflection, transmission, and absorption characteristics of terrestrial clouds and discuss the accuracy of the approximations used within the model. A Fortran implementation of CLOUD is available for download. This model is fast, accurate, and capable of calculating multiple radiative characteristics of cloudy media including the spherical and plane albedo, reflection and transmission functions, absorptance as well as global and diffuse transmittance. The approximations are based on the asymptotic solutions of the radiative transfer equations valid at cloud optical thicknesses larger than 5. While the analytic part of the solutions is treated in the code in an approximate way, the correspondent reflection function (RF of a semi-infinite water cloud R∞ is calculated using numerical solutions of the radiative transfer equation in the assumption of Deirmendjian's cloud C1 model. In the case of ice clouds, the fractal ice crystal model is used. The resulting values of R∞ with respect to the viewing geometry are stored in a look-up table (LUT. The results obtained are of importance for quick estimations of main radiative characteristics of clouds and also for the solution of inverse problems.

  18. Preparation and solar reflectance spectra of chameleon-type building coatings

    Energy Technology Data Exchange (ETDEWEB)

    Yiping Ma; Beirong Zhu [Tongji Univ., Inst. of Materials Science and Engineering, Shanghai (China); Keru Wu [Tongji Univ., State Key Lab. of Concrete Materials Research, Shanghai (China)

    2001-07-01

    In this paper, the preparation of chameleon-type building coatings was investigated. The reversible thermochromic properties of chameleon-type building coatings at normal temperatures were measured, and their solar reflectance spectra were measured. The results showed that the colors of chameleon-type building coatings could be changed reversibly between red, violet etc. below 18degC and white above 18degC. The solar reflectance spectra of the coatings showed that they could absorb more solar energy below 18degC than above 18degC, which indicated that the coatings had transformed between light-absorbing and light-reflecting at normal temperatures. The characteristics of the coatings could be used to create a thermally comfortable building environment. (Author)

  19. Analysis of selective reflection spectrum in cholesteric liquid crystal cells for solar-ray controller

    Science.gov (United States)

    Ogiwara, Akifumi; Kakiuchida, Hiroshi

    2015-09-01

    The cholesteric liquid crystal (CLC) cells are fabricated by varying the concentration of various chiral dopants and liquid crystal (LC) diacrylate monomers. The wavelength and bandwidth of selective reflection spectrum in CLC cells are measured by a spectroscopic technique. The variation of the selective reflection spectrum in CLC cells is investigated by doping the different kinds of liquid crystal (LC) diacrylate monomers which stabilize a helical twisting structure by photopolymerization. The effects of the selective reflection spectrum on the visible and infrared lights in spectral solar irradiance are explained by the performance for a solar-ray controller based on the spectral solar irradiance for air mass 1.5 and the standard luminous efficiency function for photopic vision.

  20. Thermal performance of linear Fresnel reflecting solar concentrator with trapezoidal cavity absorbers

    International Nuclear Information System (INIS)

    Thermal performance of the four identical trapezoidal cavity absorbers for linear Fresnel reflecting solar device were studied and compared. The absorbers were designed for operating in conjunction with a prototype Fresnel solar reflector. Rectangular and round pipe sections were used as absorber by placing in the trapezoidal cavity. The absorber pipes were coated with ordinary dull black board paint and black nickel selective surface. The bottom of the cavity was provided with plane glass to allow the solar radiation to be reflected from the Fresnel reflector. The other three sides of the cavity absorber were insulated to reduce heat loss. Thermal performance of the Fresnel reflecting concentrator with each trapezoidal cavity absorber was studied experimentally at different concentration ratio of the reflector. The study revealed that the thermal efficiency was influenced by the concentration ratio and selective surface coating on the absorber. The thermal efficiency decreased with the increase in the concentration ratio of the Fresnel reflecting collector. The selective surface coated absorber had a significant advantage in terms of superior thermal performance as compared to ordinary black painted absorber. The round pipe (multi-tube) receiver had higher surface area to absorb solar energy as compared to rectangular pipe receiver. Thermal efficiency of the solar device with round pipe absorber was found higher (up to 8%) as compared to rectangular pipe absorber.

  1. An effective reflectance method for designing broadband antireflection films coupled with solar cells

    Institute of Scientific and Technical Information of China (English)

    Zhan Feng; He Ji-Fang; Shang Xiang-Jun; Li Mi-Feng; Ni Hai-Qiao; Xu Ying-Qiang; Niu Zhi-Chuan

    2012-01-01

    The solar spectrum covers a broad wavelength range,which requires that antireflection coating (ARC) is effective over a relatively wide wavelength range for more incident light coming into the cell.In this paper,we present two methods to measure the composite reflection of SiO2/ZnS double-layer ARC in the wavelength ranges of 300-870 nm (dualjunction) and 300-1850 nm (triple-junction),under the solar spectrum AM0.In order to give sufficient consideration to the ARC coupled with the window layer and the dispersion effect of the refractive index of each layer,we use multidimensional matrix data for reliable simulation.A comparison between the results obtained from the weighted-average reflectance (WAR) method commonly used and that from the effective-average reflectance (EAR) method introduced here shows that the optimized ARC through minimizing the effective-average reflectance is convenient and available.

  2. Study on the SiN_x/Al rear reflectance performance of crystalline silicon solar cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The performance of internal rear surface reflectance of crystalline silicon solar cells is becoming more and more important with the decrease of thickness of the silicon wafers. In this paper PC1D was used to simulate the correlations between the rear surface reflectance and the electrical as well as optical properties of the solar cells. The results showed that the short circuit current, open circuit voltage and quantum efficiency were all enhanced with the increase of the rear reflectance. When the rear reflectance increased from 60% to 100%, the short circuit current, open circuit voltage and maximum output power were improved by about 0.128 A, 0.007 V, and 0.066 W, respectively. The internal quantum efficiency was improved by 39.9%, the external quantum increased by 17.4%, and the efficiency of the solar cells was enhanced by 0.4% at 1100 nm wavelength. The screen-printing was selected to prepare SiNx/Al reflector, and experimental results showed that the SiNx/Al reflector has desired characteristic of internal rear reflectance, with the reflectivity of 15% higher than that of conventional aluminum BSF at 1100 nm wavelength.

  3. Experimental study of regenerative desiccant integrated solar dryer with and without reflective mirror

    International Nuclear Information System (INIS)

    An indirect forced convection with desiccant integrated solar dryer has been built and tested. The main parts are: a flat plate solar air collector, a drying chamber, desiccant bed and a centrifugal blower. The system is operated in two modes, sunshine hours and off sunshine hours. During sun shine hours the hot air from the flat plate collector is forced to the drying chamber for drying the product and simultaneously the desiccant bed receives solar radiation directly and through the reflected mirror. In the off sunshine hours, the dryer is operated by circulating the air inside the drying chamber through the desiccant bed by a reversible fan. The dryer is used to dry 20 kg of green peas and pineapple slices. Drying experiments were conducted with and without the integration of desiccant unit. The effect of reflective mirror on the drying potential of desiccant unit was also investigated. With the inclusion of reflective mirror, the drying potential of the desiccant material is increased by 20% and the drying time is reduced. The drying efficiency of the system varies between 43% and 55% and the pick-up efficiency varies between 20% and 60%, respectively. Approximately in all the drying experiments 60% of moisture is removed by air heated using solar energy and the remainder by the desiccant. The inclusion of reflective mirror on the desiccant bed makes faster regeneration of the desiccant material

  4. Solar-reflective coating as a cooling overlay for asphalt pavement

    Science.gov (United States)

    Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

    2012-04-01

    Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

  5. Calculation of reflectance of porous silicon double-layer antireflection coating for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Martirosyan, Kh.S.; Hovhannisyan, A.S.; Aroutiounian, V.M. [Department of Physics of Semiconductors and Microelectronics, Yerevan State University, 375025 Yerevan (Armenia)

    2007-07-01

    Calculations of the reflectance spectrum of the double-layer porous silicon antireflection coating for silicon solar cells were carried out using optical matrix approach method. Comparison of obtained reflectance spectrum of double-layer porous silicon with the spectra obtained experimentally without optimization of parameters of layers and for the SiO{sub 2}/TiO{sub 2} antireflection coating was shown lower reflectance value for this new construction proposed by us. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. On-orbit calibration of Visible Infrared Imaging Radiometer Suite reflective solar bands and its challenges using a solar diffuser.

    Science.gov (United States)

    Sun, Junqiang; Wang, Menghua

    2015-08-20

    The reflective solar bands (RSBs) of the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi National Polar-Orbiting Partnership satellite are calibrated by a solar diffuser (SD) panel whose performance is itself monitored by an accompanying solar diffuser stability monitor (SDSM). In this comprehensive work we describe the SD-based calibration algorithm of the RSBs, analyze the calibration data, and derive the performance results-the RSB calibration coefficients or F-factors-for the current three and a half years of mission. The application of the newly derived product of the SD bidirectional reflectance factor and the vignetting function for the SD screen and the newly derived SD degradation, so-called H-factors, effectively minimizes the artificial seasonal patterns in the RSB calibration coefficients due to the errors of these ingredient inputs. The full illumination region, the "sweet spot," during calibration events for SD view is carefully examined and selected to ensure high data quality and to reduce noise owing to non-fully illuminated samples. A time-dependent relative spectral response (RSR), coming from the large out-of-band contribution and the VIIRS optical system wavelength-dependent degradation, is derived from an iterative approach and applied in the SD calibration for each RSB. The result shows that VIIRS RSBs degrade much faster at near-infrared (NIR) and shortwave-infrared (SWIR) wavelength ranges due to the faster degradation of the rotating telescope assembly against the remaining part of the system. The gains of the VIIRS RSBs have degraded 2.0% (410 nm, Band M1), 0.2% (443 nm, Band M2), -0.3% (486 nm, Band M3), 0.2% (551 nm, Band M4), 6.2% (640 nm, Band I1), 11.0% (671 nm, Band M5), 21.3% (745 nm, Band M6), 35.8% (862 nm, Band I2), and 35.8% (862 nm, Band M7), respectively, since launch and 24.8% (1238 nm, Band M8), 18.5% (1378 nm, Band M9), 11.5% (1610 nm, Band I3), 11.5% (1610, Band M10), and 4.0% (2250

  7. Optical simulation of the role of reflecting interlayers in tandem micromorph silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Krc, J.; Smole, F.; Topic, M. [Ljubljana Univ. (Slovenia). Faculty of Electrical Engineering

    2005-04-01

    The role of a reflecting interlayer in micromorph silicon thin-film solar cells is investigated from the optical point of view. Detailed optical modelling and simulation are used to study the effects of different interlayers on quantum efficiency and short-circuit current of the top, amorphous silicon, and bottom, microcrystalline silicon, solar cell. The role of refractive index of interlayers on quantum efficiency of the top and bottom cell is analysed. Critical issues, such as enhanced total reflection from the solar cell and decreased quantum efficiency of the bottom cell due to interlayer are studied. Besides the single interlayer concept, double and triple interlayer stacks are investigated and improvements in comparison to the single ZnO interlayer are demonstrated. Potential thickness reductions of the top amorphous silicon cell related to different interlayers are presented. (Author)

  8. Ultrafast pump-probe reflectance spectroscopy: Why sodium makes Cu(In,Ga)Se2 solar cells better

    KAUST Repository

    Eid, Jessica

    2015-04-14

    Although Cu(In,Ga)Se2 (CIGS) solar cells have the highest efficiency of any thin-film solar cell, especially when sodium is incorporated, the fundamental device properties of ultrafast carrier transport and recombination in such cells remain not fully understood. Here, we explore the dynamics of charge carriers in CIGS absorber layers with varying concentrations of Na by femtosecond (fs) broadband pump-probe reflectance spectroscopy with 120 fs time resolution. By analyzing the time-resolved transient spectra in a different time domain, we show that a small amount of Na integrated by NaF deposition on top of sputtered Cu(In,Ga) prior to selenization forms CIGS, which induces slower recombination of the excited carriers. Here, we provide direct evidence for the elongation of carrier lifetimes by incorporating Na into CIGS.

  9. Development of a Long-Life-Cycle, Highly Water-Resistant Solar Reflective Retrofit Roof Coating

    Energy Technology Data Exchange (ETDEWEB)

    Polyzos, Georgios [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunter, Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Jaswinder [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cheng, Mengdawn [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Sharon S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Demarest, Victoria [Dow Chemical Company; Fabiny, William [Dow Chemical Company; Destaillats, Hugo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Levinson, Ronnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-03-04

    Highly water-resistant and solar-reflective coatings for low-slope roofs are potentially among the most economical retrofit approaches to thermal management of the building envelope. Therefore, they represent a key building technology research program within the Department of Energy. Research efforts in industry and the Department of Energy are currently under way to increase long-term solar reflectance on a number of fronts. These include new polymer coatings technologies to provide longer-lasting solar reflectivity and improved test methodologies to predict long-term soiling and microbial performance. The focus on long-term improvements in soiling and microbial resistance for maximum reflectance does not address the single most important factor impacting the long-term sustainability of low-slope roof coatings: excellent water resistance. The hydrophobic character of asphaltic roof products makes them uniquely suitable for water resistance, but their low albedo and poor exterior durability are disadvantages. A reflective coating that maintains very high water resistance with increased long-term resistance to soiling and microbial activity would provide additional energy savings and extend roof service life.

  10. A comprehensive ray tracing study on the impact of solar reflections from glass curtain walls.

    Science.gov (United States)

    Wong, Justin S J

    2016-01-01

    To facilitate the investigation of the impact of solar reflection from the façades of skyscrapers to surrounding environment, a comprehensive ray tracing model has been developed using the International Commerce Centre (ICC) in Hong Kong as an example. Taking into account the actual physical dimensions of buildings and meteorological data, the model simulates and traces the paths of solar reflections from ICC to the surrounding buildings, assessing the impact in terms of hit locations, light intensity and the hit time on each day throughout the year. Our analyses show that various design and architectural features of ICC have amplified the intensity of reflected solar rays and increased the hit rates of surrounding buildings. These factors include the high reflectivity of glass panels, their upward tilting angles, the concave profile of the 'Dragon Tail' (glass panels near the base), the particular location and orientation of ICC, as well as the immense height of ICC with its large reflective surfaces. The simulation results allow us to accurately map the date and time when the ray projections occur on each of the target buildings, rendering important information such as the number of converging (overlapping) projections, and the actual light intensity hitting each of the buildings at any given time. Comparisons with other skyscrapers such as Taipei 101 in Taiwan and 2-IFC (International Finance Centre) Hong Kong are made. Remedial actions for ICC and preventive measures are also discussed. PMID:26646546

  11. Solar radiation enhancement in a lean-to greenhouse by use of reflection

    International Nuclear Information System (INIS)

    Computer simulations were conducted to investigate the effects of solar radiation enhancement on the cultivated area in a Chinese style lean-to greenhouse. The results showed that, under both direct and diffuse radiation, a more uniform distribution and increased amount of reflected radiation on the cultivated area could be obtained by installing a reflector [either an aluminized reflector or a polyvinylchloride (p.v.c) film sheet] from the ridge down to the ground [arrangement (b)] than by installing it on the interiors of the north wall and roof [arrangement (a)]. Moreover, to overcome the uneven distributions of the daily transmissivity of direct radiation when installing an aluminized reflector vertically from the ridge down to the ground, caused by the second reflection during winter months at 40°N and 45°N, an improved method was adopted. This method involves manipulation of the inclination angle of the aluminized reflector according to the solar altitude in such a way that the reflected light beam from the top of the reflector reaches the southern edge of the cultivated area at any time [arrangement (c)]. The analytical results indicated that not only the distribution uniformity, but also the total amount of reflected radiation on the cultivated area was marginally improved through this adjustment. When using the aluminized reflector under direct solar radiation, values of daily reflected radiation were 0·526 for arrangement (a), 0·691 for arrangement (b) and 0.712 for arrangement (c). Consequently, values of total solar radiation (incident+reflected) reaching the cultivated area were 1·276 for arrangement (a), 1·441 for arrangement (b) and 1·462 for arrangement (c). Similar results were obtained under diffuse radiation. (author)

  12. A relation between landsat digital numbers, surface reflectance, and the cosine of the solar zenith angle

    Science.gov (United States)

    Kowalik, William S.; Marsh, Stuart E.; Lyon, Ronald J. P.

    1982-01-01

    A method for estimating the reflectance of ground sites from satellite radiance data is proposed and tested. The method uses the known ground reflectance from several sites and satellite data gathered over a wide range of solar zenith angles. The method was tested on each of 10 different Landsat images using 10 small sites in the Walker Lake, Nevada area. Plots of raw Landsat digital numbers (DNs) versus the cosine of the solar zenith angle (cos Z) for the the test areas are linear, and the average correlation coefficients of the data for Landsat bands 4, 5, 6, and 7 are 0.94, 0.93, 0.94, and 0.94, respectively. Ground reflectance values for the 10 sites are proportional to the slope of the DN versus cos Z relation at each site. The slope of the DN versus cos Z relation for seven additional sites in Nevada and California were used to estimate the ground reflectances of those sites. The estimates for nearby sites are in error by an average of 1.2% and more distant sites are in error by 5.1%. The method can successfully estimate the reflectance of sites outside the original scene, but extrapolation of the reflectance estimation equations to other areas may violate assumptions of atmospheric homogeneity.

  13. Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

    Science.gov (United States)

    Munday, Jeremy

    2016-01-01

    Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

  14. SeaWiFS long-term solar diffuser reflectance and sensor noise analyses

    International Nuclear Information System (INIS)

    The NASA Ocean Biology Processing Group's Calibration and Validation(Cal/Val) team has undertaken an analysis of the mission-long Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)solar calibration time series to assess the long-term degradation of the solar diffuser reflectance over 9 years on orbit. The SeaWiFS diffuser is an aluminum plate coated with YB71 paint. The bidirectional reflectance distribution function of the diffuser was not fully characterized before launch,so the Cal/Val team has implemented a regression of the solar incidence angles and the drift in the node of the satellite's orbit against the diffuser time series to correct for solar incidence angle effects. An exponential function with a time constant of 200 days yields the best fit to the diffuser time series.The decrease in diffuser reflectance over the mission is wavelength dependent,ranging from 9% in the blue(412 nm) to 5% in the red and near infrared(670-865 nm). The Cal/Val team has developed a methodology for computing the signal-to-noise ratio (SNR) for SeaWiFS on orbit from the diffuser time series corrected for both the varying solar incidence angles and the diffuser reflectance degradation. A sensor noise model is used to compare on-orbit SNRs computed for radiances reflected from the diffuser with prelaunch SNRs measured at typical radiances specified for the instrument. To within the uncertainties in the measurements, the SNRs for SeaWiFS have not changed over the mission. The on-orbit performance of the SeaWiFS solar diffuser should offer insight into the long-term on-orbit performance of solar diffusers on other instruments, such as the Moderate-Resolution Imaging Spectrometer [currently flying on the Earth Observing System (EOS) Terra and Aqua satellites], the Visible and Infrared Radiometer Suite [scheduled to fly on the NASA National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Project (NPP) satellites] and the Advanced Baseline

  15. Low reflectance of diamond-like carbon/porous silicon double layer antireflection coating for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V M [Department of Semiconductor Physics and Microelectronics, Yerevan State University, 1 Alex Manoogian Street, Yerevan 375025 (Armenia); Martirosyan, Kh [Department of Semiconductor Physics and Microelectronics, Yerevan State University, 1 Alex Manoogian Street, Yerevan 375025 (Armenia); Soukiassian, P [Commissariat a l' Energie Atomique, Laboratoire SIMA associe a l' Universite Paris-Sud/Orsay, DSM-DRECAM-SPCSI, Saclay, Batiment 462, 91191 Gif sur Yvette Cedex (France)

    2004-10-07

    Reflectance calculations for diamond-like carbon (DLC) antireflection thin-film coatings on porous silicon (PS) have been carried out using the optical matrix approach method. Comparison with the reflectance spectrum obtained for other antireflection coatings shows a much lower reflectance with a larger energy range including the ultraviolet, visible and infrared regions of the solar spectrum for the DLC/PS double layer. This finding is relevant in solar cell applications. (rapid communication)

  16. Design of multi-layer anti-reflection coating for terrestrial solar panel glass

    Indian Academy of Sciences (India)

    B GEETHA PRIYADARSHINI; A K SHARMA

    2016-06-01

    To date, there is no ideal anti-reflection (AR) coating available on solar glass which can effectively transmit the incident light within the visible wavelength range. However, there is a need to develop multifunctional coatingwith superior anti-reflection properties and self-cleaning ability meant to be used for solar glass panels. In spite of self-cleaning ability of materials like TiO2 and ZnO, these coatings on glass substrate have tendency to reduce lighttransmission due to their high refractive indices than glass. Thus, to infuse the anti-reflective property, a low refractive index, SiO$_2$ layer needs to be used in conjunction with TiO$_2$ and ZnO layers. In such case, the optimization ofindividual layer thickness is crucial to achieve maximum transmittance of the visible light. In the present study, we propose an omni-directional anti-reflection coating design for the visible spectral wavelength range of 400–700 nm,where the maximum intensity of light is converted into electrical energy. Herein, we employ the quarter wavelength criteria using SiO$_2$, TiO$_2$ and ZnO to design the coating composed of single, double and triple layers. The thicknessof individual layers was optimized for maximum light transmittance using essential Mcleod simulation software to produce destructive interference between reflected waves and constructive interference between transmitted waves.

  17. Experimental Approach of Reflectance Based Vicarious Calibration Method for Solar Reflectance Wavelength Region of Sensor Onboard Remote Sensing Satellites

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-12-01

    Full Text Available Experimental approach of reflectance based vicarious calibration of solar reflectance wavelength region of mission instruments onboard remote sensing satellites is conducted. As an example, vicarious calibration of ASTER/VNIR with estimated aerosol refractive index and size distribution that depends on atmospheric conditions is discussed. Strange solution of estimated refractive index and size distribution may occurred due to the fact that solution fell into one of local minima in the inversion process for phase function fitting between measured and estimated with assumed refractive index and size distribution. This paper describes atmospheric conditions that may induce such a situation. Namely, it may occur when the atmospheric optical depth is too thin and or Junge parameter is too small. In such case, refractive index and size distribution estimation accuracy is poor. A relation between refractive index and size distribution estimation accuracy and estimation accuracy of the Top of the Atmosphere (TOA radiance (vicarious calibration accuracy is also clarified in particular for ASTER/VNIR vicarious calibration. It is found that 10% of the refractive index and size distribution estimation error causes approximately 1.3% of TOA radiance estimation error.

  18. Reflections on solar collectors at elevated temperatures /260-1000 C/

    Science.gov (United States)

    Authier, B.

    1982-06-01

    Analytical models are developed for optical efficiencies and requirements of concentrating solar collectors, taking into account factors which affect the potentials for mass production. Reflective polyester films and a process to form large spherical mirrors from glass sheets have been crucial factors for lowering production costs. Microprocessors permit the nearly fully automated operation of parabolic dish point-focus and heliostat-central tower solar power plants, leaving only monitoring and maintenance for personnel. The use of GaAs-AsAl solar cells at the point focus of large spherical concentrators in the PERICLES project has yielded 22 percent energy conversion efficiences, although problems of cooling the cells have yet to be solved. Applications of the PERICLES concept for Indian village power supplies at 10 kWe/unit, while simultaneously supplying a drain hole at the center as a rainwater collection device, is described.

  19. Super-hydrophilic and solar-heat-reflective coatings for smart windows

    International Nuclear Information System (INIS)

    Hydrophilic and solar-heat-reflective coatings were deposited on glass substrates by radio-frequency sputtering. This bifunctional coating was a multilayer film consisting of SiO2, TiO2, and a heat-resistant silver alloy, which was used instead of pure silver. The multilayer film was used to improve the spectral reflection and spectral transmission properties. The heat-resistant silver alloy developed in this study facilitated the formation of an anatase layer on the surface of the coating at elevated temperatures. The photocatalytic anatase layer made the surface hydrophilic. The hydrophilic and optical properties of samples prepared at various temperatures were determined. Under ultraviolet irradiation, the water contact angle decreased from around 60° to 6° for a sample with an anatase surface layer. The sample glass reflected most of the infrared light and simultaneously transmitted visible light. - Highlights: ► Multilayer coatings for hydrophilic and solar-heat-reflective functions on glass ► Thin, heat-resistant silver alloy layer facilitated the formation of anatase. ► Photo-induced hydrophilicity was achieved using a top anatase layer. ► Drastic drop of water contact angle under UV irradiation obtained for some samples ► Excellent spectral selectivity of the TiO2/SiO2/Ag alloy/SiO2/Ag coating for daylight

  20. Broadband and omnidirectional anti-reflection layer for III/V multi-junction solar cells

    CERN Document Server

    Diedenhofen, Silke L; Haverkamp, Erik; Bauhuis, Gerard; Schermer, John; Rivas, Jaime Gómez; 10.1016/j.solmat.2012.02.022

    2012-01-01

    We report a novel graded refractive index antireflection coating for III/V quadruple solar cells based on bottom-up grown tapered GaP nanowires. We have calculated the photocurrent density of an InGaP-GaAs-InGaAsP-InGaAs solar cell with a MgF2/ZnS double layer antireflection coating and with a graded refractive index coating. The photocurrent density can be increased by 5.9 % when the solar cell is coated with a graded refractive index layer with a thickness of 1\\mu m. We propose to realize such a graded refractive index layer by growing tapered GaP nanowires on III/V solar cells. For a first demonstration of the feasibility of the growth of tapered nanowires on III/V solar cells, we have grown tapered GaP nanowires on AlInP/GaAs substrates. We show experimentally that the reflection from the nanowire coated substrate is reduced and that the transmission into the substrate is increased for a broad spectral and angular range.

  1. CLARREO: Reference Inter-Calibration on Orbit With Reflected Solar Spectrometer

    Science.gov (United States)

    Lukashin, C.; Roithmayr, C.; Currey, C.; Wielicki, B.; Goldin, D.; Sun, W.

    2016-01-01

    The CLARREO approach for reference intercalibration is based on obtaining coincident highly accurate spectral reflectance and reflected radiance measurements, and establish an on-orbit reference for existing Earth viewing reflected solar radiation sensors: CERES and VIIRS on JPSS satellites, AVHRR and follow-on imagers on MetOp, and imagers on GEO platforms. The mission goal is to be able to provide CLARREO RS reference observations that are matched in space, time, and viewing angles with measurements from the aforementioned instruments, with sampling sufficient to overcome the random error sources from imperfect data matching and instrument noise. The intercalibration method is to monitor over time changes in targeted sensor response function parameters: effective offset, gain, nonlinearity, spectral degradation, and sensitivity to polarization of optics.

  2. Ultra-low reflection porous silicon nanowires for solar cell applications

    KAUST Repository

    Najar, Adel

    2012-01-01

    High density vertically aligned Porous Silicon NanoWires (PSiNWs) were fabricated on silicon substrate using metal assisted chemical etching process. A linear dependency of nanowire length to the etching time was obtained and the change in the growth rate of PSiNWs by increasing etching durations was shown. A typical 2D bright-field TEM image used for volume reconstruction of the sample shows the pores size varying from 10 to 50 nm. Furthermore, reflectivity measurements show that the 35% reflectivity of the starting silicon wafer drops to 0.1% recorded for more than 10 μm long PSiNWs. Models based on cone shape of nanowires located in a circular and rectangular bases were used to calculate the reflectance employing the Transfert Matrix Formalism (TMF) of the PSiNWs layer. Using TMF, the Bruggeman model was used to calculate the refractive index of PSiNWs layer. The calculated reflectance using circular cone shape fits better the measured reflectance for PSiNWs. The remarkable decrease in optical reflectivity indicates that PSiNWs is a good antireflective layer and have a great potential to be utilized in radial or coaxial p-n heterojunction solar cells that could provide orthogonal photon absorption and enhanced carrier collection. ©2012 Optical Society of America.

  3. Optical design of an aspherical cylinder-type reflecting solar concentrator

    International Nuclear Information System (INIS)

    In this paper a highly efficient solar concentrating mirror is presented. A part of the aspherical cylinder's inner wall defined by a set of specific coefficients a2, a4, a6, a8, a10, a12, a14, a16 and C is used as reflective surfaces of concentrating mirror. Based on the particular aspherical equation and the optical law of reflection, the relationship between the direction vectors of the sunlight beams reflected from the cylindrical inner wall and the coefficients of an aspherical equation, a2, a4, a6, a8, a10, a12, a14, a16 and C has been derived. By optimizing these coefficients, the Sunbeams incident on the aspherical cylinder's inner wall can be focused on a very narrow line segment parallel to the cylindrical busbar and form a linear focus (focal line). The particular set of coefficients associated with the particular aspherical equation is obtained by using particle swarm optimization algorithm. The focusing effect of the solar concentrating mirror with respect to the particular set of coefficients is demonstrated by using computer simulations and the experiment. The theoretical results show that this solar concentrating mirror has a light compression ratio of about 285 to 1. The linear spot can be used as a strong light source or a high temperature heat source. - Highlights: • A part of the aspherical cylinder's inner wall is used as a concentrating mirror. • The relationship between direction vectors of reflected Sunbeams and aspheric coefficients. • The particular set of aspheric coefficients obtained with particle swarm optimization algorithm. • The Sunbeams can be focused on a very narrow line segment parallel to the cylindrical busbar. • The aspheric cylindrical concentrating mirror has a light compression ratio of 285 to 1

  4. A Traceable Ground to On-Orbit Radiometric Calibration System for the Solar Reflective Wavelength Region

    Science.gov (United States)

    Heath, Donald F.; Georgiev, Georgi

    2012-01-01

    This paper describes the combination of a Mie scattering spectral BSDF and BTDF albedo standard whose calibration is traceable to the NIST SIRCUS Facility or the NIST STARR II Facility. The Space-based Calibration Transfer Spectroradiometer (SCATS) sensor uses a simple, invariant optical configuration and dedicated narrow band spectral channel modules to provide very accurate, polarization-insensitive, stable measurements of earth albedo and lunar disk albedo. Optical degradation effects on calibration stability are eliminated through use of a common optical system for observations of the Sun, Earth, and Moon. The measurements from space would be traceable to SI units through preflight calibrations of radiance and irradiance at NIST's SIRCUS facility and the invariant optical system used in the sensor. Simultaneous measurements are made in multiple spectral channels covering the solar reflective wavelength range of 300 nm to 2.4 microns. The large dynamic range of signals is handled by use of single-element, highly-linear detectors, stable discrete electronic components, and a non imaging optical configuration. Up to 19 spectral modules can be mounted on a single-axis drive to give direct pointing at the Earth and at least once per orbit view of the Sun and Moon. By observing the Sun on every orbit, the most stringent stability requirements of the system are limited to short time periods. The invariant optical system for both radiance and irradiance measurements also give excellent transfer to-orbit SI traceability. Emerging instrumental requirements for remotely sensing tropospheric trace species have led to a rethinking by some of the paradigm for Systeme International d'Unites (SI) traceability of the spectral irradiance and radiance radiometric calibrations to spectral albedo (sr(exp -1)) which is not a SI unit. In the solar reflective wavelength region the spectral albedo calibrations are tied often to either the spectral albedo of a solar diffuser or the Moon

  5. VIIRS reflective solar bands on-orbit calibration and performance: a three-year update

    Science.gov (United States)

    Sun, Junqiang; Wang, Menghua

    2014-11-01

    The on-orbit calibration of the reflective solar bands (RSBs) of VIIRS and the result from the analysis of the up-to-date 3 years of mission data are presented. The VIIRS solar diffuser (SD) and lunar calibration methodology are discussed, and the calibration coefficients, called F-factors, for the RSBs are given for the latest reincarnation. The coefficients derived from the two calibrations are compared and the uncertainties of the calibrations are discussed. Numerous improvements are made, with the major improvement to the calibration result come mainly from the improved bidirectional reflectance factor (BRF) of the SD and the vignetting functions of both the SD screen and the sun-view screen. The very clean results, devoid of many previously known noises and artifacts, assures that VIIRS has performed well for the three years on orbit since launch, and in particular that the solar diffuser stability monitor (SDSM) is functioning essentially without flaws. The SD degradation, or H-factors, for most part shows the expected decline except for the surprising rise on day 830 lasting for 75 days signaling a new degradation phenomenon. Nevertheless the SDSM and the calibration methodology have successfully captured the SD degradation for RSB calibration. The overall improvement has the most significant and direct impact on the ocean color products which demands high accuracy from RSB observations.

  6. Turbulence in the sub-Alfv\\'enic solar wind driven by reflection of low-frequency Alfv\\'en waves

    CERN Document Server

    Verdini, A; Buchlin, E

    2009-01-01

    We study the formation and evolution of a turbulent spectrum of Alfv\\'en waves driven by reflection off the solar wind density gradients, starting from the coronal base up to 17 solar radii, well beyond the Alfv\\'enic critical point. The background solar wind is assigned and 2D shell models are used to describe nonlinear interactions. We find that the turbulent spectra are influenced by the nature of reflected waves. Close to the base, these give rise to a flatter and steeper spectrum for the outgoing and reflected waves respectively. At higher heliocentric distance both spectra evolve toward an asymptotic Kolmogorov spectrum. The turbulent dissipation is found to account for at least half of the heating required to sustain the background imposed solar wind and its shape is found to be determined by the reflection-determined turbulent heating below 1.5 solar radii. Therefore reflection and reflection-driven turbulence are shown to play a key role in the accelerationof the fast solar wind and origin of the tur...

  7. Spectral Kernel Approach to Study Radiative Response of Climate Variables and Interannual Variability of Reflected Solar Spectrum

    Science.gov (United States)

    Jin, Zhonghai; Wielicki, Bruce A.; Loukachine, Constantin; Charlock, Thomas P.; Young, David; Noeel, Stefan

    2011-01-01

    The radiative kernel approach provides a simple way to separate the radiative response to different climate parameters and to decompose the feedback into radiative and climate response components. Using CERES/MODIS/Geostationary data, we calculated and analyzed the solar spectral reflectance kernels for various climate parameters on zonal, regional, and global spatial scales. The kernel linearity is tested. Errors in the kernel due to nonlinearity can vary strongly depending on climate parameter, wavelength, surface, and solar elevation; they are large in some absorption bands for some parameters but are negligible in most conditions. The spectral kernels are used to calculate the radiative responses to different climate parameter changes in different latitudes. The results show that the radiative response in high latitudes is sensitive to the coverage of snow and sea ice. The radiative response in low latitudes is contributed mainly by cloud property changes, especially cloud fraction and optical depth. The large cloud height effect is confined to absorption bands, while the cloud particle size effect is found mainly in the near infrared. The kernel approach, which is based on calculations using CERES retrievals, is then tested by direct comparison with spectral measurements from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) (a different instrument on a different spacecraft). The monthly mean interannual variability of spectral reflectance based on the kernel technique is consistent with satellite observations over the ocean, but not over land, where both model and data have large uncertainty. RMS errors in kernel ]derived monthly global mean reflectance over the ocean compared to observations are about 0.001, and the sampling error is likely a major component.

  8. LEICA: A low energy ion composition analyzer for the study of solar and magnetospheric heavy ions

    International Nuclear Information System (INIS)

    The SAMPEX LEICA instrument is designed to measure ∼0.5--5 MeV/nucleon solar and magnetospheric ions over the range form He--Ni. The instrument is a time-of-flight mass spectrometer which measures particle time-of-flight over a ∼0.5 m path, and the residual energy deposited in an array of Si solid state detectors. Large area microchannel plates are used, resulting in a large geometrical factor for the instrument (0.6 cm2 sr) which is essential for accurate compositional measurements in small solar flares, and in studies of precipitating magnetospheric heavy ions

  9. Switch programming of reflectivity control devices for the coupled dynamics of a solar sail

    Science.gov (United States)

    Hu, Tianjian; Gong, Shengping; Mu, Junshan; Li, Junfeng; Wang, Tianshu; Qian, Weiping

    2016-03-01

    As demonstrated in the Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS), reflectivity control devices (RCDs) are switched on or off independently with each other, which has nevertheless been ignored by many previous researches. This paper emphasizes the discrete property of RCDs, and aims to obtain an appropriate switch law of RCDs for a rigid spinning solar sail. First, the coupled attitude-orbit dynamics is derived from the basic solar force and torque model into an underdetermined linear system with a binary set constraint. Subsequently, the coupled dynamics is reformulated into a constrained quadratic programming and a basic gradient projection method is designed to search for the optimal solution. Finally, a circular sail flying in the Venus rendezvous mission demonstrates the model and method numerically, which illustrates approximately 103 km terminal position error and 0.5 m/s terminal velocity error as 80 independent RCDs are switched on or off appropriately.

  10. Applying spaceborne reflectivity measurements for calculation of the solar ultraviolet radiation at ground level

    Directory of Open Access Journals (Sweden)

    P. N. den Outer

    2012-12-01

    Full Text Available Long-term analysis of cloud effects on ultraviolet (UV radiation on the ground using spaceborne observations requires the use of instruments that have operated consecutively. The longest data record can be built from the reflectivity measurements produced by the instruments Total Ozone Mapping Spectrometers (TOMS flown on Nimbus 7 from 1979 to 1992, TOMS on Earth Probe from 1996 to 2005, and the Ozone Monitoring Instrument (OMI flown on EOS Aura since 2004. The reflectivity data produced by TOMS on Earth Probe is only included until 2002. A comparison is made with cloud effects inferred from ground-based pyranometer measurements at over 83 World Radiation Data Centre stations. Modelled UV irradiances utilizing the standard reflectivity are compared with measurements of UV irradiances at eight European low-elevation stations. The reflectivity data of the two TOMS instruments shows a consistent agreement, and the required corrections are of low percentage, i.e. 2–3%. In contrast, the reflectivity product of OMI requires correction of 7–10%, and a solar angle dependency therein is more pronounced. These corrections were inferred from a comparison with pyranometer data, and tested using the UV measurements. The average reduction of UV radiation due to clouds for all sites together indicates a small trend: a diminishing cloudiness, in line with ground-based UV observations. Uncorrected implementation of the reflectivity data would have indicated the opposite.

    An optimal area was established for reflectivity data for the calculation of daily sums of UV radiation. It measures approximately 1.25° in latitudinal direction for square-shaped areas overhead the ground-based UV stations. Such an area can be traversed within 5 to 7 h at the average wind speeds found for the West European continent.

  11. Progress on alternative method of the on-orbit RVS characterization for MODIS reflective solar bands

    Science.gov (United States)

    Chen, H.; Xiong, X.; Angal, A.; Geng, X.; Wu, A.

    2014-09-01

    MODIS Reflective Solar Bands (RSB) are calibrated on-orbit using its onboard calibrators, including a Solar Diffuser (SD), a Solar Diffuser Stability Monitor (SDSM), and a Spectroradiometric Calibration Assembly (SRCA). A Space View (SV) port is used to provide a background reference, and also facilitate near monthly lunar observations via a spacecraft roll. In every scan, the earth's surface, SV and onboard calibrators are viewed via a two sided scan mirror, whose reflectance depends on the angles of the incidence (AOI) as well as the wavelength of the incident light. Response versus Scan angle (RVS) is defined as a dependence function of the scan mirror's reflectance over AOI. An initial RVS for each RSB was measured prelaunch for both Terra and Aqua MODIS. Algorithms have been developed to track the on-orbit RVS variation using the measurements from the onboard calibrators, supplemented with the Earth View (EV) response from pseudo-invariant desert targets obtained at different AOI. The current approach, as implemented in Collection 6 (C6), uses EV responses from the Libyan desert sites to track the on-orbit RVS change. It strongly depends on the long-term temporal stability of the desert sites. As an effort to validate and, if necessary, to improve MODIS RSB RVS characterization for future applications, the MODIS Characterization Support Team (MCST) has developed and tested an alternative approach to monitor the on-orbit RVS change, using a response from a single desert site. The purpose of using data from one site is to avoid the impact of possible differences in the long-term temporal stability among multiple sites on the calculation of the on-orbit RVS. This paper updates recent progress in the formulation of the alternative RVS approach. Comprehensive comparisons were also performed with current C6 RVS results for both Terra and Aqua MODIS. Results demonstrate that this alternative method provides a supplemental means to track the on-orbit RVS for MODIS RSB.

  12. Performance of "Moth Eye" Anti-Reflective Coatings for Solar Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.; Kane, M.; Jiang, P.

    2011-03-14

    An inexpensive, effective anti-reflective coating (ARC) has been developed at the University of Florida to significantly enhance the absorption of light by silicon in solar cells. This coating has nano-scale features, and its microstructure mimics that of various night active insects (e.g. a moth's eye). It is a square array of pillars, each about 700 nm high and having a diameter of about 300 nm. Samples of silicon having this coating were exposed either to various combinations of either elevated temperature and humidity or to gamma irradiation ({sup 60}Co) at the Savannah River National Laboratory, or to a broad spectrum ultraviolet light and to a 532 nm laser light at the University of Florida. The anti-reflective properties of the coatings were unaffected by any of these environmental stresses, and the microstructure of the coating was also unaffected. In fact, the reflectivity of the gamma irradiated ARC became lower (advantageous for solar cell applications) at wavelengths between 400 and 1000 nm. These results show that this coating is robust and should be tested in actual systems exposed to either weather or a space environment. Structural details of the ARCs were studied to optimize their performance. Square arrays performed better than hexagonal arrays - the natural moth-eye coating is indeed a square array. The optimal depth of the templated nanopillars in the ARC was investigated. A wet etching technology for ARC formation was developed that would be less expensive and much faster than dry etching. Theoretical modeling revealed that dimple arrays should perform better than nipple arrays. A method of fabricating both dimple and nipple arrays having the same length was developed, and the dimple arrays performed better than the nipple arrays, in agreement with the modeling. The commercial viability of the technology is quite feasible, since the technology is scalable and inexpensive. This technology is also compatible with current industrial

  13. Survey and analyze the business conditions of the solar industry, April-May 1981. Task I

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The response to seminars on Making Market Regulations Work For You are described. The administration and analysis of solar system product certification are discussed. The state-of-the-art in photovoltaics is reviewed. Recommendations on photovoltaics are made concerning regulatory initiatives, system experiments, patent policies, tax policies, procurements, and DOE operations. (MHR)

  14. Soil moisture estimation using reflected solar and emitted thermal infrared radiation

    Science.gov (United States)

    Jackson, R. D.; Cihlar, J.; Estes, J. E.; Heilman, J. L.; Kahle, A.; Kanemasu, E. T.; Millard, J.; Price, J. C.; Wiegand, C. L.

    1978-01-01

    Classical methods of measuring soil moisture such as gravimetric sampling and the use of neutron moisture probes are useful for cases where a point measurement is sufficient to approximate the water content of a small surrounding area. However, there is an increasing need for rapid and repetitive estimations of soil moisture over large areas. Remote sensing techniques potentially have the capability of meeting this need. The use of reflected-solar and emitted thermal-infrared radiation, measured remotely, to estimate soil moisture is examined.

  15. Mechanical grooving of oxidized porous silicon to reduce the reflectivity of monocrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zarroug, A.; Dimassi, W.; Ouertani, R.; Ezzaouia, H. [Laboratoire de Photovoltaique, Centre des Recherches et des Technologies de l' Energie, BP. 95, Hammam-Lif 2050 (Tunisia)

    2012-10-15

    In this work, we are interested to use oxidized porous silicon (ox-PS) as a mask. So, we display the creating of a rough surface which enhances the absorption of incident light by solar cells and reduces the reflectivity of monocrystalline silicon (c-Si). It clearly can be seen that the mechanical grooving enables us to elaborate the texturing of monocrystalline silicon wafer. Results demonstrated that the application of a PS layer followed by a thermal treatment under O2 ambient easily gives us an oxide layer of uniform size which can vary from a nanometer to about ten microns. In addition, the Fourier transform infrared (FTIR) spectroscopy investigations of the PS layer illustrates the possibility to realize oxide layer as a mask for porous silicon. We found also that this simple and low cost method decreases the total reflectivity (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Optical reflectance of pyrheliometer absorption cavities: progress toward SI-traceable measurements of solar irradiance.

    Science.gov (United States)

    Patrick, Heather J; Germer, Thomas A; Zarobila, Clarence J; Cooksey, Catherine C; Yoon, Howard W

    2016-08-10

    We have accurately determined the absorptance of three pyrheliometer cavities at 532 nm by measuring the residual reflectance using an angle-resolved bidirectional reflectometer. Measurements were performed at a normal incidence as a function of the viewing angle and position on the cavity cone. By numerically integrating the measured angle-resolved scatter over both the direction and position and accounting for an obstructed view of the cavity, we determined that the effective cavity reflectance was between 8×10-4 and 9×10-4. Thus, the absorptance of the three cavities ranged from 0.99909±0.00014 to 0.99922±0.00012 (k=2 combined expanded uncertainties). These measurements, when extended over the spectral range of operation of the pyrheliometer, are required to establish SI traceability for absolute solar irradiance measurements. PMID:27534478

  17. Reflectance spectrum of diamond-like carbon/porous silicon double-layer antireflection coatings designed for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V.M.; Martirosyan, Kh.S. [Department of Physics of Semiconductors and Microelectronics, Yerevan State University, 375025 Yerevan (Armenia); Soukiassian, P.G. [Commissariat a l' Energie Atomique, Laboratoire SIMA associe a l' Universite de Paris-Sud/Orsay, DSM/DRECAM/SPCSI, Batiment 462, Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2007-07-01

    In this study, our purpose was to investigate the possibility of using a diamond-like carbon/porous silicon double-layer antireflection coating which is characterized by low reflectance, in order to enhance the performance of silicon solar cells and to protect them from various external influences. Experimental results obtained from reflectance measurements showed the possibility of achieving low reflectance value. Theoretical simulations of the reflectance spectra were carried out. The comparison of the reflectance spectrum of such diamond-like carbon/porous silicon double layer antireflection coating with spectra obtained from other types of coating layers showed a much lower reflectance within larger energy range including the UV, visible and infrared regions of the solar spectrum. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Life Cycle Assessment of a HYSOL Concentrated Solar Power Plant: Analyzing the Effect of Geographic Location

    OpenAIRE

    Corona Bellostas, Blanca; Ruiz, Diego; San Miguel Alfaro, Guillermo

    2016-01-01

    Concentrating Solar Power (CSP) technology is developing in order to achieve higher energy efficiency, reduced economic costs, and improved firmness and dispatchability in the generation of power on demand. To this purpose, a research project titled HYSOL has developed a new power plant, consisting of a combined cycle configuration with a 100 MWe steam turbine and an 80 MWe gas-fed turbine with biomethane. Technological developments must be supported by the identification, quantification, and...

  19. Variation of reflected radiation from all reflectors of a flat plate solar collector during a year

    International Nuclear Information System (INIS)

    In this paper the impact of flat plate reflectors (bottom, top, left and right reflectors) made of Al, on total solar radiation on a solar collector during a day time over a whole year is analyzed. An analytical model for determining optimum tilt angles of a collector and reflectors for any point on the Earth is proposed. Variations of reflectors' optimal inclination angles with changes of the collector's optimal tilt angle during the year are also calculated. Optimal inclination angles of the reflectors for the South directed solar collector are calculated and compared to experimental data. It is shown that optimal inclination of the bottom reflector is the lowest in December and the highest in June, while for the top reflector the lowest value is in June and the highest value is in December. On the other hand, optimal inclination of the left and right side reflectors for optimum tilt angle of the collector does not change during the year and it is 66°. It is found that intensity of the solar radiation on the collector increases for about 80% in the summer period (June–September) by using optimally inclined reflectors, in comparison to the collector without reflectors. - Highlights: • The impacts of flat plate reflectors on solar radiation on the collector are given. • The results of the optimal inclinations of reflectors during the year are shown. • The solar radiation on the collector with reflectors is 80% higher in the summer. • This model may be applied on thermal, PV, PV/T and energy harvesting systems

  20. Methods for Analyzing the Economic Value of Concentrating Solar Power with Thermal Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Miller, Mackay [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhou, Ella [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wang, Caixia [State Grid Energy Research Inst., Beijing (China)

    2015-07-20

    Concentrating solar power with thermal energy storage (CSP-TES) provides multiple quantifiable benefits compared to CSP without storage or to solar photovoltaic (PV) technology, including higher energy value, ancillary services value, and capacity value. This report describes modeling approaches to quantifying these benefits that have emerged through state-level policymaking in the United States as well as the potential applicability of these methods in China. The technical potential for CSP-TES in China is significant, but deployment has not yet achieved the targets established by the Chinese government. According to the 12th Five Year Plan for Renewable Energy (2011-2015), CSP was expected to reach 1 GW by 2015 and 3 GW by 2020 in China, yet as of December 2014, deployment totaled only 13.8 MW. One barrier to more rapid deployment is the lack of an incentive specific to CSP, such as a feed-in tariff. The 13th Five Year Plan for Solar Generation (2016-2020), which is under development, presents an opportunity to establish a feed-in tariff specific to CSP. This report, produced under the auspices of the U.S.-China Renewable Energy Partnership, aims to support the development of Chinese incentives that advance CSP deployment goals.

  1. Reflectivity, polarization properties, and durability of metallic mirror coatings for the European Solar Telescope

    Science.gov (United States)

    Feller, A.; Krishnappa, N.; Pleier, O.; Hirzberger, J.; Jobst, P. J.; Schürmann, M.

    2012-09-01

    In the context of the conceptual design study for the European Solar Telescope (EST) we have investigated different metallic mirror coatings in terms of reflectivity, polarization properties and durability. Samples of the following coating types have been studied: bare aluminum, silver with different dielectric layers for protection and UV enhancement, and an aluminum-silver combination. From 2009 to 2011 we have carried out a long-term durability test under realistic observing conditions at the VTT solar telescope of the Observatorio del Teide (Tenerife, Spain), accompanied by repeated reflectivity measurements in the EST spectral working range (0.3 - 20 μm), and by polarization measurements in the visible range. The test results allow us to find the optimum coatings for the different mirrors in the EST beampath and to eventually assess aging effects and re-coating cycles. The results of the polarization measurements are a valuable input for an EST telescope polarization model, helping to meet the stringent requirements on polarimetric accuracy.

  2. Control of back surface reflectance from aluminum alloyed contacts on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cudzinovic, M.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    A process for forming highly reflective aluminum back contacts with low contact resistance to silicon solar cells is described. By controlling the process conditions, it is possible to vary the silicon/aluminum interface from a specular to a diffuse reflector while maintaining a high interface reflectance. The specular interface is found to be a uniform silicon/aluminum alloy layer a few angstroms thick that has epitaxially regrown on the silicon. The diffuse interface consists of randomly distributed (111) pyramids produced by crystallographic out-diffusion of the bulk silicon. The light trapping ability of the diffuse contact is found to be close to the theoretical limit. Both types of contacts are found to have specific contact resistivities of 10{sup {minus}5} {Omega}-cm{sup 2}. The process for forming the contacts involves illuminating the devices with tungsten halogen lamps. The process is rapid (under 100 s) and low temperature (peak temperature < 580{degrees}C), making it favorable for commercial solar cell fabrication.

  3. Potential benefits of solar reflective car shells: cooler cabins, fuel savings and emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Pan, Heng; Ban-Weiss, George; Rosado, Pablo; Paolini, Riccardo; Akbari, Hashem

    2011-05-11

    Abstract: Vehicle thermal loads and air conditioning ancillary loads are strongly influenced by the absorption of solar energy. The adoption of solar reflective coatings for opaque surfaces of the vehicle shell can decrease the ?soak? temperature of the air in the cabin of a vehicle parked in the sun, potentially reducing the vehicle?s ancillary load and improving its fuel economy by permitting the use of a smaller air conditioner. An experimental comparison of otherwise identical black and silver compact sedans indicated that increasing the solar reflectance (?) of the car?s shell by about 0.5 lowered the soak temperature of breath-level air by about 5?6?C. Thermal analysis predicts that the air conditioning capacity required to cool the cabin air in the silver car to 25?C within 30min is 13percent less than that required in the black car. Assuming that potential reductions in AC capacity and engine ancillary load scale linearly with increase in shell solar reflectance, ADVISOR simulations of the SC03 driving cycle indicate that substituting a typical cool-colored shell (?=0.35) for a black shell (?=0.05) would reduce fuel consumption by 0.12L per 100km (1.1percent), increasing fuel economy by 0.10kmL?1 [0.24mpg] (1.1percent). It would also decrease carbon dioxide (CO2) emissions by 2.7gkm?1 (1.1percent), nitrogen oxide (NOx) emissions by 5.4mgkm?1 (0.44percent), carbon monoxide (CO) emissions by 17mgkm?1 (0.43percent), and hydrocarbon (HC) emissions by 4.1mgkm?1 (0.37percent). Selecting a typical white or silver shell (?=0.60) instead of a black shell would lower fuel consumption by 0.21L per 100km (1.9percent), raising fuel economy by 0.19kmL?1 [0.44mpg] (2.0percent). It would also decrease CO2 emissions by 4.9gkm?1 (1.9percent), NOx emissions by 9.9mgkm?1 (0.80percent), CO emissions by 31mgkm?1 (0.79percent), and HC emissions by 7.4mgkm?1 (0.67percent). Our simulations may underestimate emission reductions because emissions in standardized driving cycles are

  4. Effects of composition and exposure on the solar reflectance of Portland cement concrete

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem

    2001-12-21

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Simulations of the influence of pavement albedo on air temperature in Los Angeles predict that increasing the albedo of 1,250 km2 of pavement by 0.25 would save cooling energy worth $15M yr-1, and reduce smog-related medical and lost-work expenses by $76M yr-1. Most sidewalks and a small fraction of roads and parking areas are paved with portland cement concrete, which can be made quite reflective through suitable choice of cement and aggregate. Variations with composition and environmental exposure of the albedos of portland cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Twenty-four mixes yielded substandard, ''rough'' concretes due to high, unmet aggregate water demand. The albedos of the remaining eight ''smooth'' concrete mixes ranged from 0.41 to 0.77 (mean 0.59). Simulated weathering, soiling, and abrasion each reduced average concrete albedo (mean decreases 0.06, 0.05, and 0.19, respectively), though some samples became slightly more reflective through weathering or soiling. Simulated rain (wetting) strongly depressed the albedos of concretes (mean decrease 0.23) until their surfaces were dried. Concrete albedo grew as the cement hydration reaction progressed (mean increase 0.08), but stabilized within six weeks of casting. White-cement concretes were on average significantly more reflective than gray-cement concretes. The albedo of the most-reflective white-cement concrete was 0.18 to 0.39 higher than that of the most-reflective gray-cement concrete, depending on state of exposure. Concrete albedo generally correlated with cement albedo and sand albedo, and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance

  5. Life Cycle Assessment of a HYSOL Concentrated Solar Power Plant: Analyzing the Effect of Geographic Location

    Directory of Open Access Journals (Sweden)

    Blanca Corona

    2016-05-01

    Full Text Available Concentrating Solar Power (CSP technology is developing in order to achieve higher energy efficiency, reduced economic costs, and improved firmness and dispatchability in the generation of power on demand. To this purpose, a research project titled HYSOL has developed a new power plant, consisting of a combined cycle configuration with a 100 MWe steam turbine and an 80 MWe gas-fed turbine with biomethane. Technological developments must be supported by the identification, quantification, and evaluation of the environmental impacts produced. The aim of this paper is to evaluate the environmental performance of a CSP plant based on HYSOL technology using a Life Cycle Assessment (LCA methodology while considering different locations. The scenarios investigated include different geographic locations (Spain, Chile, Kingdom of Saudi Arabia, Mexico, and South Africa, an alternative modelling procedure for biomethane, and the use of natural gas as an alternative fuel. Results indicate that the geographic location has a significant influence on the environmental profile of the HYSOL CSP plant. The results obtained for the HYSOL configuration located in different countries presented significant differences (between 35% and 43%, depending on the category, especially in climate change and water stress categories. The differences are mainly attributable to the local availability of solar and water resources and composition of the national electricity mix. In addition, HYSOL technology performs significantly better when hybridizing with biomethane instead of natural gas. This evidence is particularly relevant in the climate change category, where biomethane hybridization emits 27.9–45.9 kg CO2 eq per MWh (depending on the biomethane modelling scenario and natural gas scenario emits 264 kg CO2 eq/MWh.

  6. Analysis of partial-reflection data from the solar eclipse of 10 Jul. 1972. [ground-based experiment using vertical incident radio waves partially reflected from D region

    Science.gov (United States)

    Bean, T. A.; Bowhill, S. A.

    1973-01-01

    Partial-reflection data collected for the eclipse of July 10, 1972 as well as for July 9 and 11, 1972, are analyzed to determine eclipse effects on D-region electron densities. The partial-reflection experiment was set up to collect data using an on-line PDP-15 computer and DECtape storage. The electron-density profiles show good agreement with results from other eclipses. The partial-reflection programs were changed after the eclipse data collection to improve the operation of the partial-reflection system. These changes were mainly due to expanded computer hardware and have simplified the operations of the system considerably.

  7. Analyzing luminescent solar concentrators with front-facing photovoltaic cells using weighted Monte Carlo ray tracing

    Science.gov (United States)

    Woei Leow, Shin; Corrado, Carley; Osborn, Melissa; Isaacson, Michael; Alers, Glenn; Carter, Sue A.

    2013-06-01

    Luminescent solar concentrators (LSC) collect ambient light from a broad range of angles and concentrate the captured light onto photovoltaic (PV) cells. LSCs with front-facing cells collect direct and indirect sunlight ensuring a gain factor greater than one. The flexible placement and percentage coverage of PV cells on the LSC panel allow for layout adjustments to be made in order to balance re-absorption losses and the level of light concentration desired. A weighted Monte Carlo ray tracing program was developed to study the transport of photons and loss mechanisms in the LSC to aid in design optimization. The program imports measured absorption/emission spectra of an organic luminescent dye (LR305), the transmission coefficient, and refractive index of acrylic as parameters that describe the system. Simulations suggest that for LR305, 8-10 cm of luminescent material surrounding the PV cell yields the highest increase in power gain per unit area of LSC added, thereby determining the ideal spacing between PV cells in the panel. For rectangular PV cells, results indicate that for each centimeter of PV cell width, an additional increase of 0.15 mm to the waveguide thickness is required to efficiently transport photon collected by the LSC to the PV cell with minimal loss.

  8. Effects of soiling and cleaning on the reflectance and solar heat gain of a light-colored roofing membrane

    Science.gov (United States)

    Levinson, Ronnen; Berdahl, Paul; Asefaw Berhe, Asmeret; Akbari, Hashem

    A roof with high solar reflectance and high thermal emittance (e.g., a white roof) stays cool in the sun, reducing cooling power demand in a conditioned building and increasing summertime comfort in an unconditioned building. The high initial solar reflectance of a white membrane roof (circa 0.8) can be lowered by deposition of soot, dust, and/or biomass (e.g., fungi or algae) to about 0.6; degraded solar reflectances range from 0.3 to 0.8, depending on exposure. We investigate the effects of soiling and cleaning on the solar spectral reflectances and solar absorptances of 15 initially white or light-gray polyvinyl chloride membrane samples taken from roofs across the United States. Black carbon and organic carbon were the two identifiable strongly absorbing contaminants on the membranes. Wiping was effective at removing black carbon, and less so at removing organic carbon. Rinsing and/or washing removed nearly all of the remaining soil layer, with the exception of (a) thin layers of organic carbon and (b) isolated dark spots of biomass. Bleach was required to clear these last two features. At the most soiled location on each membrane, the ratio of solar reflectance to unsoiled solar reflectance (a measure of cleanliness) ranged from 0.41 to 0.89 for the soiled samples; 0.53 to 0.95 for the wiped samples; 0.74 to 0.98 for the rinsed samples; 0.79 to 1.00 for the washed samples; and 0.94 to 1.02 for the bleached samples. However, the influences of membrane soiling and cleaning on roof heat gain are better gauged by fractional variations in solar absorptance. Solar absorptance ratios (indicating solar heat gain relative to that of an unsoiled membrane) ranged from 1.4 to 3.5 for the soiled samples; 1.1 to 3.1 for the wiped samples; 1.0 to 2.0 for the rinsed samples; 1.0 to 1.9 for the washed samples; and 0.9 to 1.3 for the bleached samples.

  9. A Maximum Likelihood Approach to Determine Sensor Radiometric Response Coefficients for NPP VIIRS Reflective Solar Bands

    Science.gov (United States)

    Lei, Ning; Chiang, Kwo-Fu; Oudrari, Hassan; Xiong, Xiaoxiong

    2011-01-01

    Optical sensors aboard Earth orbiting satellites such as the next generation Visible/Infrared Imager/Radiometer Suite (VIIRS) assume that the sensors radiometric response in the Reflective Solar Bands (RSB) is described by a quadratic polynomial, in relating the aperture spectral radiance to the sensor Digital Number (DN) readout. For VIIRS Flight Unit 1, the coefficients are to be determined before launch by an attenuation method, although the linear coefficient will be further determined on-orbit through observing the Solar Diffuser. In determining the quadratic polynomial coefficients by the attenuation method, a Maximum Likelihood approach is applied in carrying out the least-squares procedure. Crucial to the Maximum Likelihood least-squares procedure is the computation of the weight. The weight not only has a contribution from the noise of the sensor s digital count, with an important contribution from digitization error, but also is affected heavily by the mathematical expression used to predict the value of the dependent variable, because both the independent and the dependent variables contain random noise. In addition, model errors have a major impact on the uncertainties of the coefficients. The Maximum Likelihood approach demonstrates the inadequacy of the attenuation method model with a quadratic polynomial for the retrieved spectral radiance. We show that using the inadequate model dramatically increases the uncertainties of the coefficients. We compute the coefficient values and their uncertainties, considering both measurement and model errors.

  10. USE OF INCIDENT AND REFLECTED SOLAR PARTICLE BEAMS TO TRACE THE TOPOLOGY OF MAGNETIC CLOUDS

    International Nuclear Information System (INIS)

    Occasionally, large solar energetic particle (SEP) events occur inside magnetic clouds (MCs). In this work, the onset time analysis, the peak intensity analysis, and the decay phase analysis of SEPs are used to investigate two large SEP events inside MCs: the 1998 May 2 and 2002 April 21 events. The onset time analysis of non-relativistic electrons and ∼MeV nucleon–1 heavy ions shows the stability of the magnetic loop structure during a period of a few hours in the events examined. The joint analysis of pitch-angle distributions and peak intensities of electrons exhibits that, depending on the particle pitch angle observed at 1 AU, in the April event the reflection point of particles may be distributed along a wide spatial range, implying that the magnetic loop is a magnetic bottle connected to the Sun with both legs. In contrast, in the May event particle reflection occurs abruptly at the magnetic mirror formed by a compressed field enhancement behind the interplanetary shock, consistent with its open field line topology.

  11. Characterization of MODIS mirror side difference in the reflective solar spectral region

    Science.gov (United States)

    Geng, X.; Angal, A.; Sun, J.; Wu, A.; Choi, T.; Xiong, X.

    2011-10-01

    The MODIS instruments onboard the Terra and Aqua spacecraft, launched in December 1999 and May 2002, respectively, have successfully operated through the present time. MODIS collects the Earth view (EV) data via a twosided paddle wheel scan mirror at angles of incidence (AOI) from 10.5 to 65.5 degrees. Reflective properties between the two mirror sides are not identical with large differences seen in Terra MODIS reflective solar bands (RSB). This paper describes a methodology to calculate and monitor MODIS RSB mirror side differences using EV observations. The longterm trends of response differences between two mirror sides are evaluated using different EV targets. Results show that the on-orbit changes in the properties of the scan mirror are wavelength and AOI dependent with large mirror side differences observed at shorter wavelengths in larger AOI. Starting from 2005, the mirror side difference has gradually exhibited a seasonally dependent feature in Terra MODIS visible spectral bands, which is mainly due to the changes in the scan mirror polarization property. In addition to fully characterizing on-orbit changes of the MODIS scan mirror properties, results and discussions provided in this paper will help clarify their impacts on the Level 1B data products and support future efforts to maintain MODIS data quality.

  12. USE OF INCIDENT AND REFLECTED SOLAR PARTICLE BEAMS TO TRACE THE TOPOLOGY OF MAGNETIC CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lun C. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Malandraki, Olga E.; Dorrian, Gareth [Institute of Astronomy and Astrophysics, National Observatory of Athens (Greece); Reames, Donald V. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Ng, Chee K. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Wang Linghua, E-mail: ltan@umd.edu [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)

    2012-05-10

    Occasionally, large solar energetic particle (SEP) events occur inside magnetic clouds (MCs). In this work, the onset time analysis, the peak intensity analysis, and the decay phase analysis of SEPs are used to investigate two large SEP events inside MCs: the 1998 May 2 and 2002 April 21 events. The onset time analysis of non-relativistic electrons and {approx}MeV nucleon{sup -1} heavy ions shows the stability of the magnetic loop structure during a period of a few hours in the events examined. The joint analysis of pitch-angle distributions and peak intensities of electrons exhibits that, depending on the particle pitch angle observed at 1 AU, in the April event the reflection point of particles may be distributed along a wide spatial range, implying that the magnetic loop is a magnetic bottle connected to the Sun with both legs. In contrast, in the May event particle reflection occurs abruptly at the magnetic mirror formed by a compressed field enhancement behind the interplanetary shock, consistent with its open field line topology.

  13. Comparison of Measurements and FluorMOD Simulations for Solar Induced Chlorophyll Fluorescence and Reflectance of a Corn Crop under Nitrogen Treatments [SIF and Reflectance for Corn

    Science.gov (United States)

    Middleton, Elizabeth M.; Corp, Lawrence A.; Campbell, Petya K. E.

    2007-01-01

    The FLuorescence Explorer (FLEX) satellite concept is one of six semifinalist mission proposals selected in 2006 for pre-Phase studies by the European Space Agency (ESA). The FLEX concept proposes to measure passive solar induced chlorophyll fluorescence (SIF) of terrestrial ecosystems. A new spectral vegetation Fluorescence Model (FluorMOD) was developed to include the effects of steady state SIF on canopy reflectance. We used our laboratory and field measurements previously acquired from foliage and canopies of corn (Zea mays L.) under controlled nitrogen (N) fertilization to parameterize and evaluate FluorMOD. Our data included biophysical properties, fluorescence (F) and reflectance spectra for leaves; reflectance spectra of canopies and soil; solar irradiance; plot-level leaf area index; and canopy SIF emissions determined using the Fraunhofer Line Depth principal for the atmospheric telluric oxygen absorption features at 688 nm (O2-beta) and 760 nm (O2-alpha). FluorMOD simulations implemented in the default "look-up-table" mode did not reproduce the observed magnitudes of leaf F, canopy SIF, or canopy reflectance. However, simulations for all of these parameters agreed with observations when the default FluorMOD information was replaced with measurements, although N treatment responses were underestimated. Recommendations were provided to enhance FluorMOD's potential utility in support of SIF field experiments and studies of agriculture and ecosystems.

  14. The area of applicability of apparatus for analyzing the spectral characteristics of reflection, albedo and color parameters of flat objects

    Science.gov (United States)

    Gorbunova, Elena V.; Chertov, Aleksandr N.; Peretyagin, Vladimir S.; Lastovskaia, Elena A.; Korotaev, Valery V.

    2015-03-01

    Quality control of different coatings (colorful, paint, marker, safety, etc.) that are applied to the surface of various objects (both metallic and non-metallic) is an important problem. Also, there is a problem of dealing with counterfeit products. So it's necessary to distinguish the fake replicas of marking from the authentic marking of producer. To solve these problems, we propose an automated apparatus for analysis and control of spectral reflection characteristics, albedo and color parameters of extended (up to 150 mm × 150 mm) flat objects. It allows constructing the color image of the object surface as well as its multispectral images in different regions of the spectrum. Herewith the color of the object surface can be calculated for various standard light sources (A, B, C, D65, E, F2, F7, F11, GE), or to any light source with a predetermined emission spectrum. The paper presents the description of working principles of the proposed apparatus as well as the results of reflection and multispectral analysis of different flat objects.

  15. Diurnal and seasonal dynamics of canopy-level solar-induced chlorophyll fluorescence and spectral reflectance indices in a cornfield

    Science.gov (United States)

    A collaborative field campaign was undertaken to examine the temporal dynamics of canopy-level solar-induced fluorescence (SIF) and the Photochemical Reflectance Index (PRI) in conjunction with photosynthetic light use efficiency (LUE) obtained from fluxes measured at an instrumented tower. We condu...

  16. Results from solar reflective band end-to-end testing for VIIRS F1 sensor using T-SIRCUS

    Science.gov (United States)

    McIntire, Jeff; Moyer, David; McCarthy, James K.; Brown, Steven W.; Lykke, Keith R.; De Luccia, Frank; Xiong, Xiaoxiong; Butler, James J.; Guenther, Bruce

    2011-10-01

    Verification of the Visible Infrared Imager Radiometer Suite (VIIRS) End-to-End (E2E) sensor calibration is highly recommended before launch, to identify any anomalies and to improve our understanding of the sensor onorbit calibration performance. E2E testing of the Reflective Solar Bands (RSB) calibration cycle was performed pre-launch for the VIIRS Flight 1 (F1) sensor at the Ball Aerospace facility in Boulder CO in March 2010. VIIRS reflective band calibration cycle is very similar to heritage sensor MODIS in that solar illumination, via a diffuser, is used to correct for temporal variations in the instrument responsivity. Monochromatic light from the NIST T-SIRCUS (Traveling Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources) was used to illuminate both the Earth View (EV), via an integrating sphere, and the Solar Diffuser (SD) view, through a collimator. The collimator illumination was cycled through a series of angles intended to simulate the range of possible angles for which solar radiation will be incident on the solar attenuation screen on-orbit. Ideally, the measured instrument responsivity (defined here as the ratio of the detector response to the at-sensor radiance) should be the same whether the EV or SD view is illuminated. The ratio of the measured responsivities was determined at each collimator angle and wavelength. In addition, the Solar Diffuser Stability Monitor (SDSM), a ratioing radiometer designed to track the temporal variation in the SD Bidirectional Reflectance Factor (BRF) by direct comparison to solar radiation, was illuminated by the collimator. The measured SDSM ratio was compared to the predicted ratio. An uncertainty analysis was also performed on both the SD and SDSM calibrations.

  17. Recombination rates in heterojunction silicon solar cells analyzed by impedance spectroscopy at forward bias and under illumination

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Sero, Ivan; Luo, Yan; Garcia-Belmonte, Germa; Bisquert, Juan [Departament de Fisica, Universitat Jaume I, E-12071 Castello (Spain); Munoz, Delfina; Voz, Cristobal; Puigdollers, Joaquim; Alcubilla, Ramon [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain)

    2008-04-15

    Impedance spectroscopy (at forward bias and under illumination) of solar cells comprised thin hydrogenated amorphous silicon (a-Si:H) films deposited on crystalline silicon (c-Si) wafers was analyzed in terms of ac equivalent circuits. Shockley-Read-Hall recombination at states on the device interfaces governs the cell dynamic response. Recombination process was modeled by means of simple RC circuits which allow to determine the capture rate of electrons and holes. Carrier lifetime is found to be stated by the electron capture time {tau}{sub SRH}{approx}{tau}{sub n}, and it results in the range of 300 {mu}s. The Al-annealed back contact was regarded as the dominating recombination interface. (author)

  18. A robust method for determining calibration coefficients for VIIRS reflective solar bands

    Science.gov (United States)

    Ji, Qiang; McIntire, Jeffrey; Efremova, Boryana; Schwarting, Thomas; Oudrari, Hassan; Zeng, Jinan; Xiong, Xiaoxiong

    2015-09-01

    This paper presents a robust method for determining the calibration coefficients in polynomial calibration equations, and discusses the corresponding calibration uncertainties. An attenuator method that takes into account all measurements with and without an attenuator screen was used to restrict the impact of the absolute calibration of the light source. The originally proposed procedure attempts to simultaneously determine all unknowns nonlinearly using polynomial curve fitting. The newly proposed method divides the task into two simpler parts. For example, in the case of a quadratic calibration equation, the first part becomes a quadratic equation solely for the transmittance of attenuator, which has an analytical solution using three or four sets of measurements. Additionally, it is straightforward to determine the median value and the standard deviation of the transmittance from the solutions using all combinations of measured data points. In conjunction, the second part becomes a linear fit, with the ratio of the zeroth-order to first-order calibration coefficients as the intercept and the ratio of the second-order to first-order calibration coefficients as the slope. These ratios are unaffected by the absolute calibration of the light source and are then used in the calibration equation to calculate the first-order calibration coefficient. How the new method works is straightforward to visualize, which makes its results easier to verify. This is demonstrated using measurements from the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) reflective solar bands (RSB) pre-launch testing.

  19. Characterization of NPP Visible/Infrared Imager Radiometer Suite (VIIRS) Reflective Solar Bands Dual Gain Anomaly

    Science.gov (United States)

    Lee, Shihyan; McIntire, Jeff; Oudari, Hassan

    2012-01-01

    The Visible/Infrared Imager Radiometer Suite (VIIRS) contains six dual gain bands in the reflective solar spectrum. The dual gain bands are designed to switch gain mode at pre-defined thresholds to achieve high resolution at low radiances while maintaining the required dynamic range for science. During pre-launch testing, an anomaly in the electronic response before transitioning from high to low gain was discovered and characterized. On-orbit, the anomaly was confirmed using MODIS data collected during Simultaneous Nadir Overpasses (SNOs). The analysis of the Earth scene data shows that dual gain anomaly can be determined at the orbital basis. To characterize the dual gain anomaly, the anomaly region and electronic offsets were tracked per week during the first 8 month of VIIRS operation. The temporal analysis shows the anomaly region can drift 20 DN and is impacted by detectors DC Restore. The estimated anomaly flagging regions cover 2.5 % of the high gain dynamic range and are consistent with prelaunch and on-orbit LUT. The prelaunch results had a smaller anomaly range (30-50 DN) and are likely the results of more stable electronics from the shorter data collection time. Finally, this study suggests future calibration efforts to focus on the anomaly's impact on science products and possible correction method to reduce uncertainties.

  20. Linking solar induced fluorescence and the photochemical reflectance index to carbon assimilation in a cornfield

    Science.gov (United States)

    Cheng, Y.; Middleton, E.; Zhang, Q.; Corp, L.; Campbell, P. K.; Huemmrich, K. F.; Kustas, W.; Daughtry, C. S.; Dulaney, W. P.; Russ, A.

    2012-12-01

    Determining the health and vigor of vegetation using high spectral resolution remote sensing techniques is a critical component in monitoring productivity from both natural and managed ecosystems and their feedbacks to climate. This presentation summarizes a field campaign conducted in a USDA-ARS experimental cornfield site located in Beltsville, MD, USA over a five-year period. The site is equipped with an instrumented tower which makes continuous eddy covariance measurements of CO2 along with incoming PAR. Hyperspectral reflectance observations were acquired over corn canopies with a USB4000 Miniature Fiber Optic Spectrometer (Ocean Optics Inc., Dunedin, Florida, USA) at multiple times a day at various stages through the growing season. On all field days, supporting plant information and leaf level data were acquired (e.g., CO2 gas exchange) as well as biophysical field data, including leaf area index (LAI), mid-day canopy PAR transmission, soil reflectivity, and soil moisture. The canopy optical measurements enabled retrievals of the photochemical reflectance index (PRI) and solar induced fluorescence (SIF) centered at O2-A and -B bands. These two spectrally based bio-indicators have been widely utilized in studies to assess whether vegetation is performing near-optimally or exhibiting symptoms of environmental stress (e.g., drought or nutrient deficiency, non-optimal temperatures, etc.). Both SIF and PRI expressed diurnal dynamics and seasonal changes that followed environmental conditions and physiological status of the cornfield. We further investigated the correlation between these two retrievals and the flux tower based carbon assimilation observations (i.e. gross ecosystem production, GEP). We were able to successfully model the variation of GEP (r2=0.81; RMSE=0.18 mg CO2/m2/s) by utilizing both SIF and PRI. Several cross-validation algorithms were applied to the model to demonstrate the robustness and consistency of the model. Our results suggest great

  1. Backscattered energetic neutral atoms from the Moon in the Earth's plasma sheet observed by Chandarayaan-1/Sub-keV Atom Reflecting Analyzer instrument

    Science.gov (United States)

    Harada, Yuki; Futaana, Yoshifumi; Barabash, Stas; Wieser, Martin; Wurz, Peter; Bhardwaj, Anil; Asamura, Kazushi; Saito, Yoshifumi; Yokota, Shoichiro; Tsunakawa, Hideo; Machida, Shinobu

    2014-05-01

    We present the observations of energetic neutral atoms (ENAs) produced at the lunar surface in the Earth's magnetotail. When the Moon was located in the terrestrial plasma sheet, Chandrayaan-1 Energetic Neutrals Analyzer (CENA) detected hydrogen ENAs from the Moon. Analysis of the data from CENA together with the Solar Wind Monitor (SWIM) onboard Chandrayaan-1 reveals the characteristic energy of the observed ENA energy spectrum (the e-folding energy of the distribution function) ˜100 eV and the ENA backscattering ratio (defined as the ratio of upward ENA flux to downward proton flux) particles backscattered as ENAs from the lunar surface. The observed ENA backscattering ratio in the plasma sheet exhibits no significant difference in the Southern Hemisphere, where a large and strong magnetized region exists, compared with that in the Northern Hemisphere. This is contrary to the CENA observations in the solar wind, when the backscattering ratio drops by ˜50% in the Southern Hemisphere. Our analysis and test particle simulations suggest that magnetic shielding of the lunar surface in the plasma sheet is less effective than in the solar wind due to the broad velocity distributions of the plasma sheet protons.

  2. An Optical Characterization Technique for Parabolic Trough Solar Collectors Using Images of the Absorber Reflection

    Science.gov (United States)

    Owkes, Jeanmarie Kathleen

    As the concentrating solar power industry competes to develop a less-expensive parabolic trough collector, assurance is needed that new parabolic trough collectors maintain accurate optical alignment. Previous optical characterization techniques are either too slow, ill-suited for field testing, or do not allow the collector to be tested in realistic orientations. The Observer method presented here enables the rapid optical characterization of parabolic trough collectors in any orientation in the field. The Observer method directly measures the combined optical angular errors in the reflector surface shape and the absorber position, which can be separated into its two components: reflector surface slope and absorber misalignment. The data acquisition requires the placement of photogrammetry targets on and around the collector. Multiple photographs of the absorber and its reflection are taken with a digital camera from different angles with respect to the collector. The images are processed to determine the camera location of each image using photogrammetry bundle analysis. The absorber and its reflection are found in the photographs using image-processing techniques. A Monte Carlo uncertainty model was developed to determine the uncertainty in the Observer measurements. The uncertainty was estimated for a wide array of measurement test scenarios to demonstrate the user's control over the measurement uncertainty. To validate the Observer method, the absorber alignment technique was compared to traditional photogrammetry; the absorber position measured with the two methods compared with a root-mean-square difference of 1.5 mm in the transverse direction and 0.86 mm along the optical axis. The reflector surface slope error measurement was compared to both VSHOT and SOFAST, two well-established optical characterization tools, by measuring a single reflector panel in the laboratory. The VSHOT and SOFAST measurements agreed with the Observer with a root

  3. Texturing of the Silicon Substrate with Nanopores and Si Nanowires for Anti-reflecting Surfaces of Solar Cells

    Directory of Open Access Journals (Sweden)

    A.A. Druzhinin

    2015-06-01

    Full Text Available The paper presents the prospects of obtaining a functional multi-layer anti-reflecting coating of the front surface of solar cells by texturing the surface of the silicon by electrochemical etching. The physical model of the "Black Si" coating with discrete inhomogeneity of the refractive index and technological aspects of producing of "Black Si" functional anti-reflecting coatings were presented. The investigation results of the spectral characteristics of the obtained multilayer multiporous "Black Si" coatings for silicon solar cells made by electrochemical etching are presented. The possibility of creating the texture on a silicon wafer surface using silicon nanowires and ordered nanopores obtained by metal-assisted chemical etching was shown.

  4. The Orbitrap mass analyzer as a space instrument for the understanding of prebiotic chemistry in the Solar System

    Science.gov (United States)

    Vuitton, Véronique; Briois, Christelle; Makarov, Alexander

    Over the past decade, it has become apparent that organic molecules are widespread in our Solar System and beyond. The better understand of the prebiotic chemistry leading to their formation is a primary objective of many ongoing space missions. Cassini-Huygens revealed the existence of very large molecular structures in Titan's atmosphere as well as on its surface, in the form of dune deposits, but their exact nature remains elusive. One key science goal of the Mars Science Laboratory Curiosity rover is to assess the presence of organics on the red planet. Rosetta will characterize the elemental and isotopic composition of the gas and dust ejected from comet Churyumov-Gerasimenko, while amino acids have been detected in meteorites. This search for complex organics relies heavily on mass spectrometry, which has the remarkable ability to analyze and quantify species from almost any type of sample (provided that the appropriate sampling and ionizing method is used). Because of the harsh constraints of the spatial environment, the mass resolution of the spectrometers onboard current space probes is quite limited compared to laboratory instruments, leading to significant limitations in the scientific return of the data collected. Therefore, future in situ solar system exploration missions would significantly benefit from instruments relying on High Resolution Mass Spectrometry (HRMS). Since 2009, 5 French laboratories (LPC2E, IPAG, LATMOS, LISA, CSNSM) involved in the chemical investigation of solar system bodies form a Consortium to develop HRMS for future space exploration, based on the use of the Orbitrap technology (C. Briois et al., 2014, to be submitted). The work is undertaken in close collaboration with the Thermo Fisher Scientific Company, which commercializes Orbitrap based laboratory instruments. The Orbitrap is an electrostatic mass analyzer, it is compact, lightweight, and can reach a good sensitivity and dynamic range. A prototype is under development at

  5. Optical coherence tomography and autofluorescence findings in chronic phototoxic maculopathy secondary to snow-reflected solar radiation

    Directory of Open Access Journals (Sweden)

    Dhananjay Shukla

    2015-01-01

    Full Text Available A professional mountain trekker presented with gradual, moderate visual decline in one eye. The subnormal vision could not be explained by the examination of anterior and posterior segment of either eye, which was unremarkable. Optical coherence tomography and autofluorescence imaging revealed subtle defects in the outer retina, which correlated with the extent of visual disturbance. A novel presentation of retinal phototoxicity due to indirect solar radiation reflected from snow in inadequately protected eyes of a chronically exposed subject is reported.

  6. Sensitivity Analysis and Error Analysis of Reflectance Based Vicarious Calibration with Estimated Aerosol Refractive Index and Size Distribution Derived from Measured Solar Direct and Diffuse Irradiance as well as Measured Surface Reflectance

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-12-01

    Full Text Available Sensitivity analysis and error of reflectance based vicarious calibration with estimated aerosol refractive index and size distribution derived from measured solar direct and diffuse irradiance as well as measured surface reflectance is conducted for solar reflective channels of mission instruments onboard remote sensing satellites. Through these error analyses, it is found that the most influencing factor is surface reflectance. The most significant 75 to 91% of vicarious calibration coefficients error is due to surface reflectance followed by atmospheric optical depth and Junge parameter. Therefore, we have to care about surface reflectance measuring accuracy followed by atmospheric optical depth (aerosol refractive index, and water vapor and ozone absorption and Junge parameter (aerosol size distribution. As a conclusion, it is confirmed that surface reflectance is most influencing factor on TOA radiance. When the atmospheric optical depth is small, then Junge parameter is influencing.

  7. Instrumentation and First Results of the Reflected Solar Demonstration System for the Climate Absolute Radiance and Refractivity Observatory

    Science.gov (United States)

    McCorkel, Joel; Thome, Kurtis; Hair, Jason; McAndrew, Brendan; Jennings, Don; Rabin, Douglas; Daw, Adrian; Lundsford, Allen

    2012-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission key goals include enabling observation of high accuracy long-term climate change trends, use of these observations to test and improve climate forecasts, and calibration of operational and research sensors. The spaceborne instrument suites include a reflected solar spectroradiometer, emitted infrared spectroradiometer, and radio occultation receivers. The requirement for the RS instrument is that derived reflectance must be traceable to Sl standards with an absolute uncertainty of <0.3% and the error budget that achieves this requirement is described in previo1L5 work. This work describes the Solar/Lunar Absolute Reflectance Imaging Spectroradiometer (SOLARIS), a calibration demonstration system for RS instrument, and presents initial calibration and characterization methods and results. SOLARIS is an Offner spectrometer with two separate focal planes each with its own entrance aperture and grating covering spectral ranges of 320-640, 600-2300 nm over a full field-of-view of 10 degrees with 0.27 milliradian sampling. Results from laboratory measurements including use of integrating spheres, transfer radiometers and spectral standards combined with field-based solar and lunar acquisitions are presented. These results will be used to assess the accuracy and repeatability of the radiometric and spectral characteristics of SOLARIS, which will be presented against the sensor-level requirements addressed in the CLARREO RS instrument error budget.

  8. Schottky Diode Applications of the Fast Green FCF Organic Material and the Analyze of Solar Cell Characteristics

    Science.gov (United States)

    Çaldiran, Z.; Aydoğan, Ş.; İncekara, Ü.

    2016-05-01

    In this study, a device applications of organic material Fast Green FCF (C37H34N2Na2O10S3Na2) has been investigated. After chemical cleaning process of boron doped H-Si crystals, Al metal was coated on the one surface of crystals by thermal evaporation and fast green organic materials were coated on other surface of crystals with spin coating method (coating parameters; 800 rpm for 60 s). Finally, Ni metal was coated on Fast Green by sputtering and we obtained the Ni/Fast Green FCF/n-Si/Al Schottky type diode. And then we calculated the basic diode parameters of device with current-voltage (I-V) and capacitance- voltage (C-V) measurements at the room temperature. We calculated the ideality factory (n), barrier height (Φb) of rectifing contact from I-V measurements using thermionic emission methods. Furthermore, we calculated ideality factory (n), barrier height (Φb) and series resistance (Rs) of device using Cheung and Norde functions too. The diffusion potential, barrier height, Fermi energy level and donor concentration have been determined from the linear 1/C2-V curves at reverse bias, at room temperature and various frequencies. Besides we measured the current-voltage (I-V) at under light and analyzed the characteristics of the solar cell device.

  9. Isobar separation and precision mass spectrometry of short-lived nuclides with a multi-reflection time-of-flight analyzer

    International Nuclear Information System (INIS)

    Multi reflection time of flight (MR-ToF) analyzers are low-energy (i.e. keV) table-top ion beam devices that can achieve mass resolving powers R=m/Am exceeding 100,000 on millisecond timescales. A dedicated device [was built in Greifswald and implemented in the precision Penning trap mass spectrometer ISOLTRAP at the online isotope separator ISOLDE at CERN/Geneva. It was installed between the rf quadrupole ion trap for capturing and bunching of ISOLDEs continuous 60-keV ion beam and the first of ISOLTRAP's two Penning traps. The MR-ToF analyzer consists of two electrostatic ion mirrors between which the ions are repeatedly reflected. The ions are captured and ejected by pulsing the potential of an in trap lift electrode 3]. Fig. 1: Sketch of ISOLTRAP MR-ToF mass analyzer in combination with an ion detector (top right) or a Bradbury-Nielsen gate (bottom right) [1c]. As indicated in the figure (top right), a detector behind the MR-ToF analyzer can record ToF spectra for precision mass spectrometry. Alternatively, it can be combined with a Bradbury-Nielsen gate for ion selection, i.e. for ion-beam purification. For the first direct mass measurement of the short-lived 82Zn, the latter mode was used to remove the abundant isobaric rubidium contamination. In the mass spectrometer mode, the new device allowed precision mass measurements of the low-yield - and so far unreached - exotic calcium isotopes 53,54Ca. The resulting nuclear binding energies were decisive in confirming N=32 as a magic neutron number. In addition, the MR-ToF's fast high-resolution mass analysis is an important tool for ISOLDE target and ion source developments [1C)

  10. Standard Test Method for Determining Solar or Photopic Reflectance, Transmittance, and Absorptance of Materials Using a Large Diameter Integrating Sphere

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1987-01-01

    1.1 This test method covers the measurement of the absolute total solar or photopic reflectance, transmittance, or absorptance of materials and surfaces. Although there are several applicable test methods employed for determining the optical properties of materials, they are generally useful only for flat, homogeneous, isotropic specimens. Materials that are patterned, textured, corrugated, or are of unusual size cannot be measured accurately using conventional spectrophotometric techniques, or require numerous measurements to obtain a relevant optical value. The purpose of this test method is to provide a means for making accurate optical property measurements of spatially nonuniform materials. 1.2 This test method is applicable to large specimens of materials having both specular and diffuse optical properties. It is particularly suited to the measurement of the reflectance of opaque materials and the reflectance and transmittance of semitransparent materials including corrugated fiber-reinforced plastic, ...

  11. Correcting spaceborne reflectivity measurements for application in solar ultraviolet radiation levels calculations at ground level

    Directory of Open Access Journals (Sweden)

    P. N. den Outer

    2012-01-01

    Full Text Available The Lambertian Equivalent Reflection (LER produced by satellite-carried instruments is used to determine cloud effects on ground level UltraViolet (UV radiation. The focus is on data use from consecutive operating instruments: the Total Ozone Mapping Spectrometers (TOMS flown on Nimbus 7 from 1979 to 1992, TOMS on Earth Probe from 1996 to 2005, and the Ozone Monitoring Instrument (OMI flown on Aura since 2004. The LER data produced by TOMS on Earth Probe is only included until 2002. The possibility to use the Radiative Cloud Fraction (RCF-product of OMI is also investigated. A comparison is made with cloud effects inferred from ground-based pyranometer measurements at over 83 World Radiation Data Centre stations. Modelled UV irradiances utilizing LER data are compared with measurements of UV irradiances at eight European low elevation stations. The LER data set of the two TOMS instruments shows a consistent agreement, and the required corrections are of low percentage i.e. 2–3%. In contrast, the LER data of OMI requires correction of 7–10%, and a solar angle dependency therein is more pronounced. These corrections were inferred from a comparison with pyranometer data, and tested using the UV measurements. The RCF product of OMI requires a large correction but can then be implemented as a cloud effect proxy. However, a major drawback of RCF is the large number of clipped data, i.e. 18%, and results are not better than those obtained with the corrected LER product of OMI. The average reduction of UV radiation due to clouds for all sites together indicate a small trend: a diminishing cloudiness, in line with ground-based UV observations. Uncorrected implementation of LER would have indicated the opposite. An optimal field of view of 1.25° was established for LER data to calculate UV radiations levels. The corresponding area can be traversed within 5–7 h at the average wind speeds found for the West European continent.

  12. Ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Weiquan; Becker, Jacob; Liu, Shi; Kuo, Ying-Shen; Li, Jing-Jing; Zhang, Yong-Hang [Center for Photonics Innovation and School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Landini, Barbara; Campman, Ken [Sumika Electronic Materials, Inc., Phoenix, Arizona 85034 (United States)

    2014-05-28

    This paper reports the proposal, design, and demonstration of ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer to optimize light management and minimize non-radiative recombination. According to our recently developed semi-analytical model, this design offers one of the highest potential achievable efficiencies for GaAs solar cells possessing typical non-radiative recombination rates found among commercially available III-V arsenide and phosphide materials. The structure of the demonstrated solar cells consists of an In{sub 0.49}Ga{sub 0.51}P/GaAs/In{sub 0.49}Ga{sub 0.51}P double-heterostructure PN junction with an ultra-thin 300 nm thick GaAs absorber, combined with a 5 μm thick Al{sub 0.52}In{sub 0.48}P layer with a textured as-grown surface coated with Au used as a reflective back scattering layer. The final devices were fabricated using a substrate-removal and flip-chip bonding process. Solar cells with a top metal contact coverage of 9.7%, and a MgF{sub 2}/ZnS anti-reflective coating demonstrated open-circuit voltages (V{sub oc}) up to 1.00 V, short-circuit current densities (J{sub sc}) up to 24.5 mA/cm{sup 2}, and power conversion efficiencies up to 19.1%; demonstrating the feasibility of this design approach. If a commonly used 2% metal grid coverage is assumed, the anticipated J{sub sc} and conversion efficiency of these devices are expected to reach 26.6 mA/cm{sup 2} and 20.7%, respectively.

  13. Analyze the effect of window layer (AlAs) for increasing the efficiency of GaAs based solar cell

    OpenAIRE

    Arifina Rahman Tumpa; Eity Sarker; Shagufta Anjum; Nasrin Sultana

    2015-01-01

    Solar energy is the most important renewable source and convertible into useful form with no transmission cost and environment pollution. The main drawback of currently used photovoltaic cell is its low conversion efficiency and materials with the appropriate band gaps. Recently it has been shown that the GaAs based p-i-n solar cell becomes a promising material for very high efficiency solar cell. An ideal model for p-i-n reference cell has been developed and used to theoretically explore the...

  14. Determination of the optical thickness and effective particle radius of clouds from reflected solar radiation measurements. I - Theory

    Science.gov (United States)

    Nakajima, Teruyuki; King, Michael D.

    1990-01-01

    A method is presented for determining the optical thickness and effective particle radius of stratiform cloud layers from reflected solar radiation measurements. A detailed study is presented which shows that the cloud optical thickness (tau c) and effective particle radius (r/e/) of water clouds can be determined solely from reflection function measurements at 0.75 micron and 2.16 microns, provided tau c is not less than 4 and r(e) is not less than 6 microns. For optically thin clouds, the retrieval becomes ambiguous, resulting in two possible solutions for the effective radius and optical thickness. Adding a third channel near 1.65 micron does not improve the situation noticeably, whereas the addition of a channel near 3.70 microns reduces the ambiguity in deriving the effective radius. The effective radius determined by the above procedure corresponds to the droplet radius at some optical depth within the cloud layer.

  15. Nonlinear Reflection Process of Linearly Polarized, Broadband Alfvén Waves in the Fast Solar Wind

    Science.gov (United States)

    Shoda, M.; Yokoyama, T.

    2016-04-01

    Using one-dimensional numerical simulations, we study the elementary process of Alfvén wave reflection in a uniform medium, including nonlinear effects. In the linear regime, Alfvén wave reflection is triggered only by the inhomogeneity of the medium, whereas in the nonlinear regime, it can occur via nonlinear wave-wave interactions. Such nonlinear reflection (backscattering) is typified by decay instability. In most studies of decay instabilities, the initial condition has been a circularly polarized Alfvén wave. In this study we consider a linearly polarized Alfvén wave, which drives density fluctuations by its magnetic pressure force. For generality, we also assume a broadband wave with a red-noise spectrum. In the data analysis, we decompose the fluctuations into characteristic variables using local eigenvectors, thus revealing the behaviors of the individual modes. Different from the circular-polarization case, we find that the wave steepening produces a new energy channel from the parent Alfvén wave to the backscattered one. Such nonlinear reflection explains the observed increasing energy ratio of the sunward to the anti-sunward Alfvénic fluctuations in the solar wind with distance against the dynamical alignment effect.

  16. Use of total internal reflection Raman (TIR) and attenuated total reflection infrared (ATR-IR) spectroscopy to analyze component separation in thin offset ink films after setting on coated paper surfaces.

    Science.gov (United States)

    Kivioja, Antti; Hartus, Timo; Vuorinen, Tapani; Gane, Patrick; Jääskeläinen, Anna-Stiina

    2013-06-01

    The interactive behavior of ink constituents with porous substrates during and after the offset print process has an important effect on the quality of printed products. To help elucidate the distribution of ink components between the retained ink layer and the substrate, a variety of spectroscopic and microscopic analysis techniques have been developed. This paper describes for the first time the use of total internal reflection (TIR) Raman spectroscopy to analyze the penetration behavior of separated offset ink components (linseed oil, solid color pigment) in coated papers providing chemically intrinsic information rapidly, nondestructively, and with minimal sample preparation. In addition, the already widely applied technique of attenuated total reflection infrared spectroscopy (ATR-IR) was evaluated in parallel and compared. The results of the ATR-IR Raman clearly revealed an improvement in uppermost depth resolution compared with values previously published from other nondestructive techniques, and the method is shown to be capable of providing new knowledge of the setting of thin (0.25-2 μm) offset ink films, allowing the spreading and the penetration behavior on physically different paper coating surfaces to be studied. PMID:23735252

  17. 7Be solar neutrino line: A reflection of the central temperature distribution of the Sun

    International Nuclear Information System (INIS)

    A precise test of the theory of stellar evolution can be performed by measuring the average difference in energy between the neutrino line produced by 7Be electron capture in the solar interior and the corresponding neutrino line produced in a terrestrial laboratory. This energy shift is calculated to be 1.29 keV (to an accuracy of a few percent) for the dominant ground-state to ground-state transition. The energy shift is approximately equal to the average temperature of the solar core, computed by integrating the temperature over the solar interior with a weighting factor equal to the locally produced 7Be neutrino emission. Therefore, a measurement of the energy shift is a measurement of the central temperature distribution of the Sun. The energy profile of the 7Be line is derived analytically and is evaluated numerically. The line shape is asymmetric: on the low-energy side, the line shape is Gaussian with a half-width at half-maximum of 0.6 keV and, on the high-energy side, the line shape is exponential with a half-width at half-maximum of 1.1 keV. The effective temperature of the high-energy exponential tail is 15x106 K. The energy profile of the 7Be neutrino line should be taken into account in calculations of vacuum neutrino oscillations and of the absorption cross section for 7Be solar neutrinos incident on 7Li nuclei. The characteristic modulation of the 7Be line shape that would be caused by either vacuum neutrino oscillations or by matter-enhanced (MSW) neutrino oscillations is shown to be small. Other frequently discussed weak interaction solutions to the solar neutrino problem are also not expected to change significantly the line profile

  18. Transient Response of Organo-Metal-Halide Solar Cells Analyzed by Time-Resolved Current-Voltage Measurements

    Directory of Open Access Journals (Sweden)

    M. Greyson Christoforo

    2015-11-01

    Full Text Available The determination of the power conversion efficiency of solar cells based on organo-metal-halides is subject to an ongoing debate. As solar cell devices may exhibit very slow transient response, current-voltage scans in different directions may not be congruent, which is an effect often referred to as hysteresis. We here discuss time-resolved current-voltage measurements as a means to evaluate appropriate delay times (voltage settling times to be used in current-voltage measurements of solar cells. Furthermore, this method allows the analysis of transient current response to extract time constants that can be used to compare characteristic differences between devices of varying architecture types, selective contacts and changes in devices due to storage or degradation conditions.

  19. Effect of titanium dioxide (TiO{sub 2}) on largely improving solar reflectance and cooling property of high density polyethylene (HDPE) by influencing its crystallization behavior

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shichao; Zhang, Jun, E-mail: zhangjun@njtech.edu.cn

    2014-12-25

    Highlights: • HDPE/TiO{sub 2} composites have more perfect crystal structure. • Refractive index is the key factor affecting the final solar reflectance. • HDPE/TiO{sub 2} composites can achieve high solar reflectance. • The real cooling property is in accordance with solar reflectance. - Abstract: In this study, the different crystal forms of titanium dioxide (TiO{sub 2}) were added into high density polyethylene (HDPE) to fabricate cool material. Crystal structure, crystallization behavior, crystal morphology were investigated by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarized optical microscope (POM). Scanning electron microscope (SEM) was applied to observe dispersion of TiO{sub 2} particles in the HDPE matrix and the cross section morphology. The solar reflectance and actual cooling property were evaluated by UV–Vis–NIR spectrometer and a self-designed device. By adding TiO{sub 2} particles into HDPE matrix, the polymer chain could crystallize into more perfect and thermal stable lamella. The presence of TiO{sub 2} particles dramatically increased the number of nucleation site therefore decreased the crystal size. The subsequent solar reflectance was related to the degree of crystallinity, the spherulite size of HDPE, refractive index, and distribution of TiO{sub 2} particles in HDPE matrix. It was found the rutile TiO{sub 2} could largely improve the total solar reflectance from 28.2% to 51.1%. Finally, the temperature test showed that the composites had excellent cooling property, which was in accordance with solar reflectance result.

  20. The Trade-off between Solar Reflectance and Above-Sheathing Ventilation for Metal Roofs on Residential and Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Desjarlais, Andre Omer [ORNL; Kriner, Scott [Metal Construction Association, Glenview, IL; Miller, William A [ORNL

    2013-01-01

    An alternative to white and cool-color roofs that meets prescriptive requirements for steep-slope (residential and non-residential) and low-slope (non-residential) roofing has been documented. Roofs fitted with an inclined air space above the sheathing (herein termed above-sheathing ventilation, or ASV), performed as well as if not better than high-reflectance, high-emittance roofs fastened directly to the deck. Field measurements demonstrated the benefit of roofs designed with ASV. A computer tool was benchmarked against the field data. Testing and benchmarks were conducted at roofs inclined at 18.34 ; the roof span from soffit to ridge was 18.7 ft (5.7 m). The tool was then exercised to compute the solar reflectance needed by a roof equipped with ASV to exhibit the same annual cooling load as that for a direct-to-deck cool-color roof. A painted metal roof with an air space height of 0.75 in. (0.019 m) and spanning 18.7 ft (5.7 m) up the roof incline of 18.34 needed only a 0.10 solar reflectance to exhibit the same annual cooling load as a direct-to-deck cool-color metal roof (solar reflectance of 0.25). This held for all eight ASHRAE climate zones complying with ASHRAE 90.1 (2007a). A dark heat-absorbing roof fitted with 1.5 in. (0.038 m) air space spanning 18.7 ft (5.7 m) and inclined at 18.34 was shown to have a seasonal cooling load equivalent to that of a conventional direct-to-deck cool-color metal roof. Computations for retrofit application based on ASHRAE 90.1 (1980) showed that ASV air spaces of either 0.75 or 1.5 in. (0.019 and 0.038 m) would permit black roofs to have annual cooling loads equivalent to the direct-to-deck cool roof. Results are encouraging, and a parametric study of roof slope and ASV aspect ratio is needed for developing guidelines applicable to all steep- and low-slope roof applications.

  1. Displacement damage dose used for analyzing electron irradiation-induced degradation of GaInP/GaAs/Ge space solar cells

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Displacement damage dose (Dd) approach was applied to analyze the electron irradiation-induced degradation of GaInP/ GaAs/Ge space solar cells by effective 1 MeV electron Dd, the electron irradiation-induced maximum power Pmax degradation of the solar cells is plotted as a function of the effective 1 MeV electron Dd , and the result shows that all the measured electron data can be represented by a single curve using displacement damage dose. Obviously, the displacement damage dose approach simplifies the description of electron irradiation-induced degradation of GaInP/GaAs/Ge space solar cells, and also offers an alternative for handling the case where degradation occurs as a result of combined electron and proton irradiation.

  2. Attenuated total reflectance Fourier-transform infrared spectroscopic investigation of silicon heterojunction solar cells

    Czech Academy of Sciences Publication Activity Database

    Holovský, Jakub; De Wolf, S.; Jiříček, Petr; Ballif, C.

    2015-01-01

    Roč. 86, č. 7 (2015), "073108-1"-"073108-6". ISSN 0034-6748 R&D Projects: GA ČR(CZ) GA14-05053S; GA MŠk 7E12029; GA MŠk(CZ) LM2011026 EU Projects: European Commission(XE) 283501 - FAST TRACK Institutional support: RVO:68378271 Keywords : FTIR * ATR * solar cells Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.614, year: 2014

  3. Fabrication of high infrared reflective Al-doped ZnO thin films through electropulsing treatment for solar control

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Dagang, E-mail: chinesemdg@163.com; Hu, Huawen; Gan, Lu

    2015-08-05

    Highlights: • Rapid electropulsing treatment (EPT) was applied on AZO thin films. • AZO film presented electrical resistivity of 9.03 × 10{sup −4} Ω cm after 4.5 min of EPT. • AZO film presented high infrared reflection rate of 80–85% after 4.5 min of EPT. • The prepared AZO film can be used as solar control film. - Abstract: In this study, Al-doped ZnO (AZO) thin films were finished by low-energy consumed electropulsing treatment (EPT) in a short time. The EPT effect on the resulting AZO films was investigated by X-ray Diffraction (XRD), Hall Effect measurement, UV–visible transmittance spectra, Scanning Electron Microscope (SEM), Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy. As compared with the other EPT-treated AZO films, the prepared AZO films corresponding to 4.5 min EPT exhibited higher degree of crystallization, higher visible transmittance with blue shift, smoother surface, lower electrical resistivity of 9.03 × 10{sup −4} Ω cm, and higher infrared reflection rate of 80–85%. By the 4.5 min of EPT, the electrical conductivity of the resulting AZO thin film was increased by approximately 82.3%. Moreover, it was also found that prolonged EPT would degrade the film properties. These results indicate that the fast and low-energy consumed EPT might be a promising substitution for traditional heat annealing, and the prepared high infrared reflective AZO films make them promising candidates for being applied as solar control films.

  4. Sustainable urban energy: Development of a mesoscale assessment model for solar reflective roof technologies

    International Nuclear Information System (INIS)

    Buildings and other engineered structures that form cities are responsible for a significant portion of the global and local impacts of climate change. Consequently, the incorporation of building design strategies and materials such as the use of reflective roof materials, or 'cool' roofs, are being widely investigated. However, although their benefits for individual buildings have been studied, as yet there is little understanding of the potential benefits of urban scale implementation of such systems. Here we report the development of a new methodology for assessing the potential capacity and benefits of installing reflective roofs in an urbanized area. The new methodology combines remote sensing image data with a building energy computer simulation to quantify the current rooftop reflectivity and predict the potential benefits of albedo improvement. In addition to the direct electricity savings, cool roof systems reduce peak electrical demand in the month of August when the peak demand is at its highest in the case study area. Environmental benefits associated with lowering greenhouse-gas emissions are also substantial. The new methodology allows the calculation of payback periods to assist planners to evaluate the potential economic benefits of the widespread installation of cool roof systems. - Research highlights: →Integrated remote sensing technique into building energy simulation quantifies rooftop reflectivity and predicts the potential benefits of albedo improvement. →70% buildings can improve rooftop reflectivity. →Cool roof application can reduce the study area's electrical demand by 4.3%. →Payback period will be 7-11 years depending on low and high-end cool roof cost assumptions.

  5. Analyze the effect of window layer (AlAs for increasing the efficiency of GaAs based solar cell

    Directory of Open Access Journals (Sweden)

    Arifina Rahman Tumpa

    2015-07-01

    Full Text Available Solar energy is the most important renewable source and convertible into useful form with no transmission cost and environment pollution. The main drawback of currently used photovoltaic cell is its low conversion efficiency and materials with the appropriate band gaps. Recently it has been shown that the GaAs based p-i-n solar cell becomes a promising material for very high efficiency solar cell. An ideal model for p-i-n reference cell has been developed and used to theoretically explore the current-voltage characteristics on the host cell properties. The purpose of this paper is to study the performance of AlAs material use as window layer in p-i-n reference cell instead of AlGaAs and evaluated the performance with various parameters. Short circuit current density, open circuit voltage and efficiency are needed to be calculated with the dependencies of band gap energy, carrier concentration and temperature. Significant effects of width lengths on the performance of window layer are evaluated. These calculations will do at cell temperature of 300k. After all comparing these, GaAs based p-i-n reference cell with AlAs window layer offers the maximum efficiency.

  6. Alternative Method of On-Orbit Response-Versus-Scan-Angle Characterization for MODIS Reflective Solar Bands

    Science.gov (United States)

    Chen, Hongda; Xiong, Xiaoxiong; Angal, Amit; Geng, Xu; Wu, Aisheng

    2016-01-01

    The moderate resolution imaging spectroradiometer (MODIS) has 20 reflective solar bands (RSB), covering a spectral range from 0.41 to 2.2 microns, which are calibrated on-orbit using its onboard calibrators, which include a solar diffuser, a solar diffuser stability monitor, and a spectroradiometric calibration assembly. A space view (SV) port is used to provide a background reference and also facilitates near-monthly lunar observations through a spacecraft roll. In every scan, the Earth's surface, SV, and onboard calibrators are viewed via a two-sided scan mirror, the reflectance of which depends on the angle of incidence (AOI) as well as the wavelength of the incident light. Response-versus-scan-angle (RVS) is defined as a dependence function of the scan mirror's reflectance over AOI. An initial RVS for each RSB was measured prelaunch for both Terra and Aqua MODIS. Algorithms have been developed to track the on-orbit RVS variation using the measurements from the onboard calibrators, supplemented with the earth view (EV) trends from pseudoinvariant desert targets obtained at different AOI. Since the mission beginning, the MODIS characterization support team (MCST) has dedicated efforts in evaluating approaches of characterizing the on-orbit RVS. A majority of the approaches focused on fitting the data at each AOI over time and then deriving the relative change at different AOI. The current version of the on-orbit RVS algorithm, as implemented in the collection 6 (C6) level-1B (L1B), is also based on the above rationale. It utilizes the EV response trends from the pseudoinvariant Libyan desert targets to supplement the gain derived from the onboard calibrators. The primary limitation of this approach is the assumption of the temporal stability of these desert sites. Consequently, MCST developed an approach that derives the on-orbit RVS change using measurements from a single desert site, combined with the on-orbit lunar measurements. In addition, the EV and onboard

  7. Alternative method of on-orbit response-versus-scan-angle characterization for MODIS reflective solar bands

    Science.gov (United States)

    Chen, Hongda; Xiong, Xiaoxiong; Angal, Amit; Geng, Xu; Wu, Aisheng

    2016-04-01

    The moderate resolution imaging spectroradiometer (MODIS) has 20 reflective solar bands (RSB), covering a spectral range from 0.41 to 2.2 μm, which are calibrated on-orbit using its onboard calibrators, which include a solar diffuser, a solar diffuser stability monitor, and a spectroradiometric calibration assembly. A space view (SV) port is used to provide a background reference and also facilitates near-monthly lunar observations through a spacecraft roll. In every scan, the Earth's surface, SV, and onboard calibrators are viewed via a two-sided scan mirror, the reflectance of which depends on the angle of incidence (AOI) as well as the wavelength of the incident light. Response-versus-scan-angle (RVS) is defined as a dependence function of the scan mirror's reflectance over AOI. An initial RVS for each RSB was measured prelaunch for both Terra and Aqua MODIS. Algorithms have been developed to track the on-orbit RVS variation using the measurements from the onboard calibrators, supplemented with the earth view (EV) trends from pseudoinvariant desert targets obtained at different AOI. Since the mission beginning, the MODIS characterization support team (MCST) has dedicated efforts in evaluating approaches of characterizing the on-orbit RVS. A majority of the approaches focused on fitting the data at each AOI over time and then deriving the relative change at different AOI. The current version of the on-orbit RVS algorithm, as implemented in the collection 6 (C6) level-1B (L1B), is also based on the above rationale. It utilizes the EV response trends from the pseudoinvariant Libyan desert targets to supplement the gain derived from the onboard calibrators. The primary limitation of this approach is the assumption of the temporal stability of these desert sites. Consequently, MCST developed an approach that derives the on-orbit RVS change using measurements from a single desert site, combined with the on-orbit lunar measurements. In addition, the EV and onboard

  8. Correcting spaceborne reflectivity measurements for application in solar ultraviolet radiation levels calculations at ground level

    OpenAIRE

    P. N. den Outer; Dijk, A. van; Slaper, H.; A. V. Lindfors; Backer, H; A. F. Bais; Feister, U.; Koskela, T.; Josefsson, W.

    2012-01-01

    The Lambertian Equivalent Reflection (LER) produced by satellite-carried instruments is used to determine cloud effects on ground level UltraViolet (UV) radiation. The focus is on data use from consecutive operating instruments: the Total Ozone Mapping Spectrometers (TOMS) flown on Nimbus 7 from 1979 to 1992, TOMS on Earth Probe from 1996 to 2005, and the Ozone Monitoring Instrument (OMI) flown on Aura since 2004. The LER data produced by TOMS on Earth Probe is only included until 2002. ...

  9. Low uncertainty measurements of bidirectional reflectance factor on the NPOESS/VIIRS solar diffuser

    Science.gov (United States)

    Lessel, Kristen; McClain, Stephen

    2007-09-01

    An illuminated Solar Diffuser is the calibration source for the VIS/NIR bands on the NPOESS/VIIRS sensor. We completed a set of BRF measurements to fully characterize the distribution of scattered light from the solar diffuser. NPOESS/VIIRS has an overall VIS/NIR radiometric calibration uncertainty requirement of 2%(1 sigma), of which 1.32% was allocated to the characterization of the BRF. In order to meet this requirement, we modified the existing goniometer and measurement procedure used on MODIS. Modifications include sample yoke redesign, periodic measurements of the lamp polarization coupled with stability measurements, modifications to source optics, and stray light reduction. We measured BRF in 6 spectral wavebands for 9 out-of-plane illumination angles and 2 view angles. We achieved NIST traceable measurements with an uncertainty ranging from 1.09% to 1.32%. Our measurements of a smaller Spectralon TM sample match NIST measurements of the same sample to better than 0.5%. These requirements are nominally the same as achieved on MODIS. As a result of instrument upgrades, we currently meet this overall uncertainty while having included additional uncertainty terms.

  10. Status of time-dependent response versus scan-angle (RVS) for Terra and Aqua MODIS reflective solar bands

    Science.gov (United States)

    Geng, Xu; Angal, Amit; Sun, Junqiang; Chen, Hongda; Wu, Aisheng; Li, Yonghong; Link, Daniel; Xiong, Xiaoxiong

    2014-09-01

    The MODerate resolution Imaging Spectroradiometer (MODIS) has 20 reflective solar bands (RSB), which are calibrated using a solar diffuser (SD) and near-monthly scheduled lunar observations via a space view (SV) port. The sensor responses observed at two different angles of incidence (AOI) from the SD and lunar measurements are used to track the on-orbit RSB gain changes as well as the response versus scan-angle (RVS) changes. The MODIS RSB have experienced wavelength dependent degradation since launch with the larger degradation observed at the shorter wavelengths. In addition to the SD and lunar observations, the MODIS Characterization Support Team (MCST) regularly monitors the response trending at multiple AOI over selected desert sites. In Collection 6 (C6), a new algorithm using the EV measurements from pseudoinvariant desert sites was developed to better characterize the MODIS scan-angle dependence and it led to a significant improvement in the long-term calibration consistency of the MODIS Level 1B (L1B) products. This approach is formulated for all RSB, and its application was recently extended to Terra band 10, leading to a significant improvement in the ocean-color products. This paper discusses the current status and performance of the on-orbit RVS characterization as applied in C6. Also, the various challenges and future improvement strategies associated with trending the EV response for the high-gain ocean bands are discussed.

  11. Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

    Science.gov (United States)

    Ghadiri, Elham; Zakeeruddin, Shaik M.; Hagfeldt, Anders; Grätzel, Michael; Moser, Jacques-E.

    2016-04-01

    Efficient dye-sensitized solar cells are based on highly diffusive mesoscopic layers that render these devices opaque and unsuitable for ultrafast transient absorption spectroscopy measurements in transmission mode. We developed a novel sub-200 femtosecond time-resolved diffuse reflectance spectroscopy scheme combined with potentiostatic control to study various solar cells in fully operational condition. We studied performance optimized devices based on liquid redox electrolytes and opaque TiO2 films, as well as other morphologies, such as TiO2 fibers and nanotubes. Charge injection from the Z907 dye in all TiO2 morphologies was observed to take place in the sub-200 fs time scale. The kinetics of electron-hole back recombination has features in the picosecond to nanosecond time scale. This observation is significantly different from what was reported in the literature where the electron-hole back recombination for transparent films of small particles is generally accepted to occur on a longer time scale of microseconds. The kinetics of the ultrafast electron injection remained unchanged for voltages between +500 mV and –690 mV, where the injection yield eventually drops steeply. The primary charge separation in Y123 organic dye based devices was clearly slower occurring in two picoseconds and no kinetic component on the shorter femtosecond time scale was recorded.

  12. Optical and adhesive properties of dust deposits on solar mirrors and their effects on specular reflectivity and electrodynamic cleaning for mitigating energy-yield loss

    Science.gov (United States)

    Mazumder, Malay; Yellowhair, Julius; Stark, Jeremy; Heiling, Calvin; Hudelson, John; Hao, Fang; Gibson, Hannah; Horenstein, Mark

    2014-10-01

    Large-scale solar plants are mostly installed in semi-arid and desert areas. In those areas, dust layer buildup on solar collectors becomes a major cause for energy yield loss. Development of transparent electrodynamic screens (EDS) and their applications for self-cleaning operation of solar mirrors are presented with a primary focus on the removal dust particles smaller than 30 µm in diameter while maintaining specular reflection efficiency propels the dust layer off of the collector's surface by a traveling wave. The cleaning process takes less than 2 minutes; needs energy less than 1 Wh/m2 without requiring any water or manual labor. The reflection efficiency can be restored > 95% of the original clean-mirror efficiency. We briefly present (1) loss of specular reflection efficiency as a function of particle size distribution of deposited dust, and (2) the effects of the electrode design and materials used for minimizing initial loss of specular reflectivity in producing EDS-integrated solar mirrors. Optimization of EDS by using a figure of merit defined by the ratio of dust removal efficiency to the initial loss of specular reflection efficiency is discussed.

  13. Impulsive solar X-ray bursts. 4: Polarization, directivity and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1976-01-01

    A Monte Carlo method is described for evaluation of the spectrum, directivity and polarization of X-rays diffusely reflected from stellar photospheres. the accuracy of the technique is evaluated through comparison with analytic results. Using the characteristics of the incident X-rays of the model for solar X-ray flares, the spectrum, directivity and polarization of the reflected and the total X-ray fluxes are evaluated. The results are compared with observations.

  14. Radiometric Inter-Calibration between Himawari-8 AHI and S-NPP VIIRS for the Solar Reflective Bands

    Directory of Open Access Journals (Sweden)

    Fangfang Yu

    2016-02-01

    Full Text Available The Advanced Himawari Imager (AHI on-board Himawari-8, which was launched on 7 October 2014, is the first geostationary instrument housed with a solar diffuser to provide accurate onboard calibrated data for the visible and near-infrared (VNIR bands. In this study, the Ray-matching and collocated Deep Convective Cloud (DCC methods, both of which are based on incidently collocated homogeneous pairs between AHI and Suomi NPP (S-NPP Visible Infrared Imaging Radiometer Suite (VIIRS, are used to evaluate the calibration difference between these two instruments. While the Ray-matching method is used to examine the reflectance difference over the all-sky collocations with similar viewing and illumination geometries, the near lambertian collocated DCC pxiels are used to examine the difference for the median or high reflectance scenes. Strong linear relationships between AHI and VIIRS can be found at all the paired AHI and VIIRS bands. Results of both methods indicate that AHI radiometric calibration accuracy agrees well with VIIRS data within 5% for B1-4 and B6 at mid and high reflectance scenes, while AHI B5 is generally brighter than VIIRS by ~6%–8%. No apparent East-West viewing angle dependent calibration difference can be found at all the VNIR bands. Compared to the Ray-matching method, the collocated DCC method provides less uncertainty of inter-calibration results at near-infrared (NIR bands. As AHI has similar optics and calibration designs to the GOES-R Advanced Baseline Imager (ABI, which is currently scheduled to launch in fall 2016, the on-orbit AHI data provides a unique opportunity to develop, test and examine the cal/val tools developed for ABI.

  15. A data mining approach: Analyzing wind speed and insolation period data in Turkey for installations of wind and solar power plants

    International Nuclear Information System (INIS)

    Highlights: ► Wind speed and insolation period data were analyzed using a data mining approach. ► Most of the studies in the literature were based on Weibull and Rayleigh models. ► Nearest and farest neighbor algorithms were used with different distance metrics. ► Many inferences were achieved in efficient limits for wind and solar farm analyses. - Abstract: Wind and solar power plant installations have been recently increased rapidly with respect to the depletion of fossil-based fuels all over the world. Due to stochastic nature of meteorological conditions, wind and solar energies have a non-schedulable nature and they require several installation analyses to determine the location and the capacities of wind and solar power to be produced. This paper focuses on the similarity, feasibility and numerical analyses of 75 cities in Turkey based on the monthly average wind speed and insolation period data. The nearest and the farest neighbor algorithms are used as agglomerative hierarchical clustering methods with Euclidean, Manhattan and Minkowski distance metrics in the stage of making the similarity and feasibility analyses. The maximum cophenetic correlation coefficient is achieved by the nearest neighbor algorithm with the Minkowski distance metric in the similarity and feasibility analyses. On the other hand, graphical representations of the monthly average wind speed and insolation period data are utilized for making the numerical analysis. The highest annual average wind speed and insolation period are obtained as 3.88 m/s and 8.45 h/day, respectively. Overall, many inferences were achieved in acceptable and efficient limits for wind and solar energy.

  16. Analysis of Photovoltaic Concentrating Solar Energy Systems

    OpenAIRE

    Garo Pilawjian

    2012-01-01

    In this paper the photovoltaic concentrating solar energy systems are analyzed. Both the Fresnel lens light refraction and mirror light reflection concentrating optical systems are considered. The main parameters and properties of photovoltaic concentrating solar energy systems are outlined. It is shown that the multi-parameter cost optimization is necessary to conduct to reduce the cost of photovoltaic concentrating solar energy systems.

  17. On-line, continuous monitoring in solar cell and fuel cell manufacturing using spectral reflectance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, Bhushan; Rupnowski, Przemyslaw; Ulsh, Michael

    2016-01-12

    A monitoring system 100 comprising a material transport system 104 providing for the transportation of a substantially planar material 102, 107 through the monitoring zone 103 of the monitoring system 100. The system 100 also includes a line camera 106 positioned to obtain multiple line images across a width of the material 102, 107 as it is transported through the monitoring zone 103. The system 100 further includes an illumination source 108 providing for the illumination of the material 102, 107 transported through the monitoring zone 103 such that light reflected in a direction normal to the substantially planar surface of the material 102, 107 is detected by the line camera 106. A data processing system 110 is also provided in digital communication with the line camera 106. The data processing system 110 is configured to receive data output from the line camera 106 and further configured to calculate and provide substantially contemporaneous information relating to a quality parameter of the material 102, 107. Also disclosed are methods of monitoring a quality parameter of a material.

  18. A rare gas optics-free absolute photon flux and energy analyzer for solar and planetary observations

    Science.gov (United States)

    Judge, Darrell L.

    1994-01-01

    We have developed a prototype spectrometer for space applications requiring long term absolute EUV photon flux measurements. In this recently developed spectrometer, the energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.

  19. A new approach to analyzing solar coronal spectra and updated collisional ionization equilibrium calculations. II. Additional recombination rate coefficients

    CERN Document Server

    Bryans, P; Savin, D W

    2008-01-01

    We have reanalyzed SUMER observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations. These improved CIE fractional abundances were calculated using state-of-the-art electron-ion recombination data for K-shell, L-shell, Na-like, and Mg-like ions of all elements from H through Zn and, additionally, Al- through Ar-like ions of Fe. Improved CIE calculations based on these data are presented here. We have also developed a new systematic method for determining the average emission measure (EM) and electron temperature (T_e) of an emitting plasma. With our new CIE data and our new approach for determining the average EM and T_e we have reanalyzed SUMER observations of the solar corona. We have compared our results with those of previous studies and found some significant differences for the derived EM and T_e. We have also calculated the enhancement of coronal elemental abundances compared to their photospheric abundances, using the SUMER observations themselves to determ...

  20. Design and fabrication of a SiOx/ITO double-layer anti-reflective coating for heterojunction silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.; Digdaya, A.; Santbergen, R.; Van Swaaij, R.A.C.M.M.; Zeman, M. [Photovoltaic Materials and Devices, Delft University of Technology, P.O. Box 5031, 2600 GA Delft (Netherlands); Bronsveld, P.; Van Roosmalen, J.A.M.; Weeber, A.W. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2013-10-15

    In this contribution optical simulations of both flat and textured heterojunction silicon solar cells are presented and verified experimentally. Using Advanced Semiconductor Analysis (ASA) software, we optimize a double-layer anti-reflective (AR) coating, which has an additional SiOx film on the top of the existing indium tin oxide (ITO) coating. Our approach is based on maximizing the absorbance of the crystalline silicon (c-Si) wafer, which is strongly correlated with the solar cell's short circuit current (Jsc). Our simulations show that for a flat heterojunction silicon solar cell c-Si absorbance can increase by using a double-layer AR coating instead of a single-layer AR coating. As predicted by the simulations, experimental devices show corresponding Jsc increase, leading to the increase of the solar cell efficiency. On a textured heterojunction silicon solar cell the incident light travels an oblique path through the AR coating and we use an advanced ray-tracing model to optimize the single and double-layer AR coating for this case. Our simulations show that for the textured heterojunction silicon solar cell, reflection losses are lower but parasitic absorption losses in the ITO and amorphous silicon layers play a more important role. Using a double-layer AR coating not only reduces reflection losses further, but because a thinner ITO layer can be used it also reduces parasitic absorption losses. Experimentally, our textured heterojunction silicon solar cell with a double-layer AR coating shows that the Jsc (active area) of 40.5 mA/cm{sup 2} and an efficiency of 19.0%.

  1. Intercalibration of CERES, MODIS, and MISR reflected solar radiation and its application to albedo trends

    Science.gov (United States)

    Zhan, Yizhe; Davies, Roger

    2016-06-01

    Measurements on the Terra satellite by the Cloud and the Earth's Radiant Energy System (CERES), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Multiangle Imaging Spectroradiometer (MISR), between 2001 and 2015 over the polar regions, are analyzed in order to investigate the intercalibration differences between these instruments. Direct comparisons of colocated near-nadir radiances from CERES, MODIS, and MISR show relative agreement within 2.4% decade-1. By comparison with the CERES shortwave broadband, MODIS Collection 6 is getting brighter, by 1.0 ± 0.7% decade-1 in the red band and 1.4 ± 0.7% decade-1 in the near infrared. MISR's red and near-infrared bands, however, show darkening trends of -1.0 ± 0.6% decade-1 and -1.1 ± 0.6% decade-1, respectively. The CERES/MODIS or CERES/MISR visible and near IR radiance ratio is shown to have a significant negative correlation with precipitable water content over the Antarctic Plateau. The intercalibration results successfully correct the differential top-of-atmosphere trends in zonal albedos between CERES and MISR.

  2. Silicon nitride anti-reflection coating on the glass and transparent conductive oxide interface for thin film solar cells and modules

    Science.gov (United States)

    Iwahashi, T.; Morishima, M.; Fujibayashi, T.; Yang, R.; Lin, J.; Matsunaga, D.

    2015-10-01

    Anti-reflection coating (ARC) is well known as an important technique to enhance solar cell performance. Typical ARC has been applied on the glass surface to reduce light reflection loss at the air/glass interface. However, reflection loss occurs not only at glass surface but also at other interfaces such as glass/transparent conductive oxide (TCO) interface. The refractive index of SiNx is tunable from 1.6 to 2.7, and the range from 1.7 to 2.0 is suitable for ARC at glass/TCO interface. In this study, we examined the AR effect of silicon nitride (SiNx) deposited by plasma enhanced chemical vapor deposition at the glass/TCO interface with thin film silicon solar cell and module. Reflectivity reduction of 1.6% for glass/ZnO substrate has been obtained with optimal SiNx layer, which contribute 2.0% gain in cell efficiency. Besides, we also confirmed the relative efficiency gain of around 2% for large-sized solar module, leading to a world-record large area stabilized module conversion efficiency of 12.34%.

  3. Soiling of building envelope surfaces and its effect on solar reflectance – Part II: Development of an accelerated aging method for roofing materials

    Energy Technology Data Exchange (ETDEWEB)

    Sleiman, Mohamad [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kirchstetter, Thomas W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Berdahl, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gilbert, Haley E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Quelen, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Marlot, Lea [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Preble, Chelsea V. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Chen, Sharon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Montalbano, Amandine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rosseler, Olivier [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Akbari, Hashem [Concordia Univ., Montreal (Canada); Levinson, Ronnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Destaillats, Hugo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-01-09

    Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.

  4. Development of Surfaces Optically Suitable for Flat Solar Panels. [using a reflectometer which separately evaluates spectral and diffuse reflectivities of surfaces

    Science.gov (United States)

    1979-01-01

    A reflectometer which can separately evaluate the spectral and diffuse reflectivities of surfaces is described. A phase locked detection system for the reflectometer is also described. A selective coating on aluminum potentially useful for flat plate solar collector applications is presented. The coating is composed of strongly bound copper oxide (divalent) and is formed by an etching process performed on an aluminum alloy with high copper content. Fabrication costs are expected to be small due to the one stop fabrication process. A number of conclusions gathered from the literature as to the required optical properties of flat plate solar collectors are discussed.

  5. Statistical Analysis of the Reflectivity of a Heliostats Field. Application to the CRS Heliostats Field of the Plataforma Solar de Almeria

    International Nuclear Information System (INIS)

    Reflectivity measuring in a heliostats field of a solar central tower is a task that should be performed periodically. The reflectivity of the field is a value that should be known to evaluate the system, moreover it plays an important role in several simulation codes which are useful for the daily operation of the system. When the size of the heliostats field increases (tens of heliostats) it is necessary to find a method, due to operability reasons, that allows us to offer a reflectivity value measuring only in few facets guaranteeing that the statistical error of this value is within a reasonable range. In this report a statistical analysis of the reflectivity in a heliostats field is presented. The analysis was particularized for the CRS heliostats field of the Plataforma Solar de Almeria. The results of the present study allow us to guarantee a reflectivity value of the heliostats field with a statistical error below 1% measuring only 12 facets (instead of the 1116 facets that compose the field). (Author) 6 refs

  6. Planar solar concentrator featuring alignment-free total-internal-reflection collectors and an innovative compound tracker.

    Science.gov (United States)

    Teng, Tun-Chien; Lai, Wei-Che

    2014-12-15

    This study proposed a planar solar concentrator featuring alignment-free total-internal-reflection (TIR) collectors and an innovative compound tracker. The compound tracker, combining a mechanical single-axis tracker and scrollable prism sheets, can achieve a performance on a par with dual-axis tracking while reducing the cost of the tracking system and increasing its robustness. The alignment-free TIR collectors are assembled on the waveguide without requiring alignment, so the planar concentrator is relatively easily manufactured and markedly increases the feasibility for use in large concentrators. Further, the identical TIR collector is applicable to various-sized waveguide slab without requiring modification, which facilitates flexibility regarding the size of the waveguide slab. In the simulation model, the thickness of the slab was 2 mm, and its maximal length reached 6 m. With an average angular tolerance of ±0.6°, and after considering both the Fresnel loss and the angular spread of the sun, the simulation indicates that the waveguide concentrator of a 1000-mm length provides the optical efficiencies of 62-77% at the irradiance concentrations of 387-688, and the one of a 2000-mm length provides the optical efficiencies of 52-64.5% at the irradiance concentrations of 645-1148. Alternatively, if a 100-mm horizontally staggered waveguide slab is collocated with the alignment-free TIR collectors, the optical efficiency would be greatly improved up to 91.5% at an irradiance concentration of 1098 (C(geo) = 1200X). PMID:25607496

  7. Reflectance improvement by thermal annealing of sputtered Ag/ZnO back reflectors in a-Si:H thin film silicon solar cells

    DEFF Research Database (Denmark)

    Haug, Franz-Josef; Söderström, Karin; Pahud, Céline;

    2011-01-01

    Silver can be used as the back contact and reflector in thin film silicon solar cells. When deposited on textured substrates, silver films often exhibit reduced reflectance due to absorption losses by the excitation of surface plasmon resonances. We show that thermal annealing of the silver back ...... substrate: a cell with 9.9% initial efficiency and 15.82 mA/cm2 in short circuit current is realized in n-i-p configuration. © 2011 Materials Research Society....

  8. Monitoring and Assessing the 2012 Drought in the Great Plains: Analyzing Satellite-Retrieved Solar-Induced Chlorophyll Fluorescence, Drought Indices, and Gross Primary Production

    Directory of Open Access Journals (Sweden)

    Siheng Wang

    2016-01-01

    Full Text Available We examined the relationship between satellite measurements of solar-induced chlorophyll fluorescence (SIF and several meteorological drought indices, including the multi-time-scale standard precipitation index (SPI and the Palmer drought severity index (PDSI, to evaluate the potential of using SIF to monitor and assess drought. We found significant positive relationships between SIF and drought indices during the growing season (from June to September. SIF was found to be more sensitive to short-term SPIs (one or two months and less sensitive to long-term SPI (three months than were the normalized difference vegetation index (NDVI or the normalized difference water index (NDWI. Significant correlations were found between SIF and PDSI during the growing season for the Great Plains. We found good consistency between SIF and flux-estimated gross primary production (GPP for the years studied, and synchronous declines of SIF and GPP in an extreme drought year (2012. We used SIF to monitor and assess the drought that occurred in the Great Plains during the summer of 2012, and found that although a meteorological drought was experienced throughout the Great Plains from June to September, the western area experienced more agricultural drought than the eastern area. Meanwhile, SIF declined more significantly than NDVI during the peak growing season. Yet for senescence, during which time the reduction of NDVI still went on, the reduction of SIF was eased. Our work provides an alternative to traditional reflectance-based vegetation or drought indices for monitoring and assessing agricultural drought.

  9. Statistical Analysis of the Reflectivity of a Heliostats Field. Application to the CR S Heliostats Field of the Plataforma Solar de Almeria; Analisis Estadistico de la Reflectividad de un Campo de Heliostatos CRS de la Plataforma Solar de Almeria

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Reche, J.

    2003-07-01

    Reflectivity measuring in a heliostats field of a solar central tower is a task that should performed periodically. The reflectivity of the field is a value that should be known to evaluate the system, moreover it plays an important role in several simulation codes which are useful for the daily operation of the system. When the size of the heliostats field increases (terns of heliostats) it is necessary to find a method, due to operability reasons, that allows us to offer a reflectivity value measuring only in fe facets guaranteeing that the statistical error of this value is within a reasonable range. In this report a statistical analysis of the reflectivity in a heliostats field is presented. The analysis was particularized for the CRS heliostats field of the Plataforma Solar de Almeria. The results of the present study allow us to guarantee a reflectivity value of the heliostats field with a statistical error below 1% measuring only 12 facets (instead of the 1116 facets that compose the field). (Author) 6 refs.

  10. Energy efficiency by use of automated energy-saving windows with heat-reflective screens and solar battery for power supply systems of European and Russian buildings

    Science.gov (United States)

    Zakharov, V. M.; Smirnov, N. N.; Tyutikov, V. V.; Flament, B.

    2015-10-01

    The new energy saving windows with heat-reflecting shields have been developed, and for their practical use they need to be integrated into the automated system for controlling heat supply in buildings and the efficiency of their use together with the existing energy-saving measures must be determined. The study was based on the results of field tests of windows with heat-reflective shields in a certified climate chamber. The method to determine the minimum indoor air temperature under standby heating using heat-reflective shields in the windows and multifunctional energy-efficient shutter with solar battery have been developed. Annual energy saving for the conditions of different regions of Russia and France was determined. Using windows with heat-reflecting screens and a solar battery results in a triple power effect: reduced heat losses during the heating season due to increased window resistance; lower cost of heating buildings due to lowering of indoor ambient temperature; also electric power generation.

  11. 空间用硅太阳电池带通滤波器的研究%Research of Blue/Red Reflecting for Space Silicon Solar Cell

    Institute of Scientific and Technical Information of China (English)

    雷刚; 沈禛珏; 曹佳晔

    2012-01-01

    为改善硅太阳电池在轨工作期间的性能,通过对空间用太阳电池带通滤波器结构设计和制备工艺的研究,研制出一种空间用硅太阳电池的带通滤波器并对其性能进行了测试,结果表明,采用该带通滤波器可使硅太阳电池在轨工作温度降低6°C—12°C,输出功率增加1.8%-4.1%.带通滤波器的研制对于促进高效硅太阳电池的空间应用具有积极意义.%The non-reflective silicon cells could increase cell efficiency in comparison to cells with smooth surface, while they would also increase the operational temperature as IR and UV energy is efficiently absorbed. This temperature increase completely offsets the initial efficiency gain when the non-reflective silicon cells were used in space. A Blue/Red Reflecting (BRR) for space silicon solar cell has been developed to improve the performance of silicon solar cell. The BRR consists of UVR on the front surface of the coverglass and the IRR on the rear surface produced in method of electron-beam gun evaporation with ion-assisted deposition. The operating temperature reduction between 6°C and 12°C and the in-orbit efficiency gains between 1.8% and 4.1% for silicon solar cell with BRR have been predicted. The potential benefits of the BRR are greatest for the non-reflective silicon cells.

  12. Biomimetic approaches to create anti-reflection glass surfaces for solar cells using self-organizing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Achtelik, J.; Sievers, W. [University of Paderborn, Department of Physics, 33098 Paderborn (Germany); Center of Optoelectronics and Photonics Paderborn CeOPP, 33098 Paderborn (Germany); Lindner, J.K.N., E-mail: lindner@physik.uni-paderborn.de [University of Paderborn, Department of Physics, 33098 Paderborn (Germany); Center of Optoelectronics and Photonics Paderborn CeOPP, 33098 Paderborn (Germany)

    2013-05-15

    Highlights: ► Nanostructured glass surfaces with theoretically near-to-zero reflectivity in the UVNIR region. ► Simple fabrication process using self-organization during reactive ion etching proposed. ► Prediction of optical reflectivity from AFM measured surface morphology. -- Abstract: Aiming to diminish the reflection losses of glass covered light harvesting devices, the optical reflectivity of nanostructured glass surfaces is studied theoretically and experimentally. The work is inspired by the nanoscale roughness of insect eyes, which is tried to be replicated on a technical glass surface. To this end, the reflectivity of glass surfaces with topographies represented by linear, parabolic and Fermi-shaped glass/air fill factor profiles is calculated for normal incidence. It is shown that using the latter ones, an almost complete suppression of reflections can be achieved. A simple, self-organization technique to create such Fermi-shaped filling factor profiles in glass experimentally is also presented.

  13. Enhancing Light-Trapping Properties of Amorphous Si Thin-Film Solar Cells Containing High-Reflective Silver Conductors Fabricated Using a Nonvacuum Process

    Directory of Open Access Journals (Sweden)

    Jun-Chin Liu

    2014-01-01

    Full Text Available We proposed a low-cost and highly reflective liquid organic sheet silver conductor using back contact reflectors in amorphous silicon (a-Si single junction superstrate configuration thin-film solar cells produced using a nonvacuum screen printing process. A comparison of silver conductor samples with vacuum-system-sputtered silver samples indicated that the short-circuit current density (Jsc of sheet silver conductor cells was higher than 1.25 mA/cm2. Using external quantum efficiency measurements, the sheet silver conductor using back contact reflectors in cells was observed to effectively enhance the light-trapping ability in a long wavelength region (between 600 nm and 800 nm. Consequently, we achieved an optimal initial active area efficiency and module conversion efficiency of 9.02% and 6.55%, respectively, for the a-Si solar cells. The results indicated that the highly reflective sheet silver conductor back contact reflector layer prepared using a nonvacuum process is a suitable candidate for high-performance a-Si thin-film solar cells.

  14. Efficient light incoupling into silicon thin-film solar cells by anti-reflecting MgO/high-compact-AZO with air-side textured glass

    International Nuclear Information System (INIS)

    Light incoupling effects have been enhanced at front interfaces of silicon (Si) thin-film solar cells. Firstly, a MgO thin film was introduced at glass substrate/Al-doped ZnO (AZO) interface for anti-reflection effect. We additionally found that the surface morphology of AZO films grown on MgO film after texture-etching is dependent on the compactness of AZO. For high-compact AZO films, the texture-etched MgO/AZO double layer exhibited significantly enhanced light-scattering capability. Secondly, we made textured surfaces at air/glass interface through simple plasma-etching without sacrificial layers or masks by optimizing the etching pressure. The additional air-side texture contributed to further improvement of total light scattering from the MgO/AZO-coated glass substrate. Fabricated microcrystalline Si thin-film solar cells employing the MgO coated glass with air-side surface texture showed decreased cell reflectance and increased quantum efficiency. The Jsc increased from 21.7 to 26.5 mA cm−2 and final efficiency of 9.49% was achieved. Based on our experimental results, the suggested structure, the MgO coating on glass substrate of which air-side surface is texture-etched, can offer a promising approach to improve the light incoupling and efficiency of Si thin-film solar cells. (paper)

  15. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2–Si3N4

    Science.gov (United States)

    Hernández-Pinilla, D.; Rodríguez-Palomo, A.; Álvarez-Fraga, L.; Céspedes, E.; Prieto, J.E.; Muñoz-Martín, A.; Prieto, C.

    2016-01-01

    Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2–Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating–cooling cycles are shown here. PMID:27182544

  16. User's guide to HELIOS: A computer program for modeling the optical behavior of reflecting solar concentrators. Part 1: Introduction and code input

    Science.gov (United States)

    Vittitoe, C. N.; Biggs, F.

    1981-08-01

    HELIOS is a flexible computer code for evaluating designs for central receiver, parabolic dish, and other reflecting solar energy collector systems, for safety calculations on the threat to personnel and to the facility itself, for determination of how various input parameters alter the power collected, for design trade offs, and for heliostat evaluations. Input variables include atmospheric transmission effects, reflector shape and surface errors, suntracking errors, focusing and alignment strategies, receiver design, placement positions of the tower and mirrors, and time of day and day of the year for the calculation. Complete input instructions and a description of the code structure are given.

  17. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2 -Si3N4.

    Science.gov (United States)

    Hernández-Pinilla, D; Rodríguez-Palomo, A; Álvarez-Fraga, L; Céspedes, E; Prieto, J E; Muñoz-Martín, A; Prieto, C

    2016-06-01

    Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2-Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating-cooling cycles are shown here. PMID:27182544

  18. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2–Si3N4

    Directory of Open Access Journals (Sweden)

    D. Hernández-Pinilla

    2016-06-01

    Full Text Available Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC based on a novel MoSi2–Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]. Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating–cooling cycles are shown here.

  19. Highly reflective rear surface passivation design for ultra-thin Cu(In,Ga)Se2 solar cells

    International Nuclear Information System (INIS)

    Al2O3 rear surface passivated ultra-thin Cu(In,Ga)Se2 (CIGS) solar cells with Mo nano-particles (NPs) as local rear contacts are developed to demonstrate their potential to improve optical confinement in ultra-thin CIGS solar cells. The CIGS absorber layer is 380 nm thick and the Mo NPs are deposited uniformly by an up-scalable technique and have typical diameters of 150 to 200 nm. The Al2O3 layer passivates the CIGS rear surface between the Mo NPs, while the rear CIGS interface in contact with the Mo NP is passivated by [Ga]/([Ga] + [In]) (GGI) grading. It is shown that photon scattering due to the Mo NP contributes to an absolute increase in short circuit current density of 3.4 mA/cm2; as compared to equivalent CIGS solar cells with a standard back contact. - Highlights: • Proof-of-principle ultra-thin CIGS solar cells have been fabricated. • The cells have Mo nano-particles (NPs) as local rear contacts. • An Al2O3 film passivates the CIGS rear surface between these nano-particles. • [Ga]/([Ga] + [In]) grading is used to reduce Mo-NP/CIGS interface recombination

  20. Application of refractive scintillation theory to radio transmission through the ionosphere and the solar wind, and to reflection from a rough ocean

    International Nuclear Information System (INIS)

    Previously published results concerning refractive scattering by large-scale irregularities in a phase-changing screen are combined with the theory of diffractive scattering by small-scale irregularities in order to study three intensity scintillation phenomena. The first is the reflection of radio and optical waves from an ocean surface disturbed by a spectrum of water waves. The second is the scintillation of VHF, UHF and SHF radio waves traversing the ionospheric F-region. The third is the scintillation of VHF, UHF and SHF radio waves traversing the solar wind. In each case appropriate values are chosen for the mean square fluctuation of phase, for the outer scale, for the inner scale and for the spectral index. Spectral diagrams are drawn to show how the outer scale, the inner scale, the Fresnel scale, the focal scale, the lens scale and the peak scale vary with a relevant parameter (electromagnetic wave-frequency for the ocean, RMS fractional fluctuation of ionization density for the ionosphere, and distance of closest approach to the Sun for the solar wind). For the ionosphere and the solar wind, multiple refractive scattering by weak irregularities occurs in practice whereas it is strong single scattering that is assumed in the thin-screen theory. (author)

  1. The Study of Femtosecond Laser Irradiation on GaAs Solar Cells With TiO2/SiO2 Anti-Reflection Films

    Science.gov (United States)

    Hua, Yinqun; Shi, Zhiguo; Wu, Wenhui; Chen, Ruifang; Rong, Zhen; Ye, Yunxia; Liu, Haixia

    Femtosecond laser ablation on GaAs solar cells for space power has been investigated. In particular, we studied the effects of laser energy and laser number on the ablation of solar cells. Furthermore, the morphologies and microstructure of ablation were characterized by the non-contact optical profilometer and scanning electron microscope (SEM). The photovoltaic properties were tested by the volt ampere characteristic test system. The abaltion threshold of the TiO2/SiO2 anti-reflection film of GaAs solar cells was obtained from the linear fit of the dependence of the square diameter of the ablated area with the natural logarithm of the femtosecond laser pulse energy, the resulting threshold of the laser fluence is about 0.31J/cm2, and the corresponding energy is 5.4uJ. The ablation depth showed nonlinear dependence of energy. With the fixed energy 6uJ and the increasing laser number, the damage degree increases obviously. Furthermore, the electric properties also suffer a certain degradation. Among all the evaluated electric properties, the photoelectric conversion efficiency (η) degraded remarkably.

  2. Wide angle light collection with ultralow reflection and super scattering by silicon micro-nanostructures for thin crystalline silicon solar cell applications

    Science.gov (United States)

    Das, Sonali; Kundu, Avra; Saha, Hiranmay; Datta, Swapan K.

    2016-01-01

    Conventional c-Si solar cells employ micron-sized pyramids for achieving reduced reflection (˜10%) and enhanced light trapping by multiple bounces (maximum 3) of the incident light. Alternatively, bio-mimetic, moth-eye sub-wavelength nanostructures offer broadband antireflection properties (˜3%) suitable for solar cell applications in the optical regime. However, such structures do not provide any advantage in the charge carrier extraction process as radial junctions cannot be formed in such sub-wavelength dimensions and they have high surface area causing increased charged carrier recombination. The choice of the geometry for achieving optimum photon-electron harvesting for solar applications is therefore very critical. Cross-fertilization of the conventional solar cell light-trapping techniques and the sub-wavelength nanostructures results in unique micro-nanostructures (structures having sub-wavelength dimensions as well as dimensions of the order of few microns) which provide advanced light management capabilities along with the ability of realizing radial junctions. It is seen that an ultralow reflection along with wide angle light collection is obtained which enables such structures to overcome the morning, evening and winter light losses in solar cells. Further, super-scattering in the structures offer enhanced light trapping not only in the structure itself but also in the substrate housing the structure. Ray and wave optics have been used to understand the optical benefits of the structures. It is seen that the aspect ratio of the structures plays the most significant role for achieving such light management capabilities, and efficiencies as high as 12% can be attained. Experiments have been carried out to fabricate a unique micro-nanomaze-like structure instead of a periodic array of micro-nanostructures with the help of nanosphere lithography and the MacEtch technique. It is seen that randomized micro-nanomaze geometry offers very good antireflection

  3. Wide angle light collection with ultralow reflection and super scattering by silicon micro-nanostructures for thin crystalline silicon solar cell applications

    International Nuclear Information System (INIS)

    Conventional c-Si solar cells employ micron-sized pyramids for achieving reduced reflection (∼10%) and enhanced light trapping by multiple bounces (maximum 3) of the incident light. Alternatively, bio-mimetic, moth-eye sub-wavelength nanostructures offer broadband antireflection properties (∼3%) suitable for solar cell applications in the optical regime. However, such structures do not provide any advantage in the charge carrier extraction process as radial junctions cannot be formed in such sub-wavelength dimensions and they have high surface area causing increased charged carrier recombination. The choice of the geometry for achieving optimum photon–electron harvesting for solar applications is therefore very critical. Cross-fertilization of the conventional solar cell light-trapping techniques and the sub-wavelength nanostructures results in unique micro-nanostructures (structures having sub-wavelength dimensions as well as dimensions of the order of few microns) which provide advanced light management capabilities along with the ability of realizing radial junctions. It is seen that an ultralow reflection along with wide angle light collection is obtained which enables such structures to overcome the morning, evening and winter light losses in solar cells. Further, super-scattering in the structures offer enhanced light trapping not only in the structure itself but also in the substrate housing the structure. Ray and wave optics have been used to understand the optical benefits of the structures. It is seen that the aspect ratio of the structures plays the most significant role for achieving such light management capabilities, and efficiencies as high as 12% can be attained. Experiments have been carried out to fabricate a unique micro-nanomaze-like structure instead of a periodic array of micro-nanostructures with the help of nanosphere lithography and the MacEtch technique. It is seen that randomized micro-nanomaze geometry offers very good

  4. Analysis of Photovoltaic Concentrating Solar Energy Systems

    Directory of Open Access Journals (Sweden)

    Garo Pilawjian

    2012-03-01

    Full Text Available In this paper the photovoltaic concentrating solar energy systems are analyzed. Both the Fresnel lens light refraction and mirror light reflection concentrating optical systems are considered. The main parameters and properties of photovoltaic concentrating solar energy systems are outlined. It is shown that the multi-parameter cost optimization is necessary to conduct to reduce the cost of photovoltaic concentrating solar energy systems.

  5. Y2O3: Eu3+, Tb3+ spherical particles based anti-reflection and wavelength conversion bi-functional films: Synthesis and application to solar cells

    International Nuclear Information System (INIS)

    Highlights: • Eu3+ and Tb3+ co-doped Y2O3 particles were successfully prepared. The as prepared particles can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. • Y2O3 is not only a good photoluminescence host material, but also it has high corrosion resistivity, thermal stability, and transparency from violet to infrared light. Cooperated with SiO2 sols, it could realize a better anti-reflection property. • As a proof-of-concept application, the as prepared bi-functional films could effectively improve the photoelectric conversion efficiency by 0.23% compared to pure SiO2 AR coating film and 0.55% compared to glass. - Abstract: In this study, Eu3+ and Tb3+ co-doped Y2O3 particles were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The chosen particles were added in the SiO2 sols to get anti-reflection (AR) and wavelength conversion bi-functional films. Careful investigations were carried out to find the optimum preparation conditions and proper morphology. SEM images showed that the particle sizes reduced as metal ion/urea ratio decreased. Additionally, the extracted particles turned from sphere to lamellar type when the deionized water, which was used as solvent, reduced to a certain extent. The mechanisms of the morphology formation and diversification were proposed as well. The as prepared materials can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. The spherical sample showed better luminescence performance than the one with lamellar morphology. In addition, the optical transmittance spectra indicated that the films adding spherical particles had better anti-reflective performance, and the best adding amount was 0.08 g. Finally, As a proof-of-concept application, the as prepared bi-functional films were used to test the standard

  6. Relationship of transpiration and evapotranspiration to solar radiation and spectral reflectance in soybean [Glycine max] canopies: A simple method for remote sensing of canopy transpiration

    International Nuclear Information System (INIS)

    Abstract The study investigated diurnal and seasonal dynamics of evapotranspiration (ET) and transpiration (Tr) in a soybean canopy, as well as the relationships among ET, Tr, solar radiation and remotely sensed spectral reflectance. The eddy covariance method (ECM) and stem heat balance method (SHBM) were used for independent measurement of ET and Tr, respectively. Micrometeorological, soil, and spectral reflectance data were acquired for the entire growing season. The instantaneous values of canopy-Tr estimated by SHBM and ET by ECM were well synchronized with each other, and both were strongly affected by the solar radiation. The daily values canopy-Tr increased rapidly with increasing leaf area index (LAI), and got closer to the ET even at a low value of LAI such as 1.5-2. The daily values of ET were moderately correlated with global solar radiation (Rs), and more closely with the potential evapotranspiration (ETp), estimated by the 'radiation method.' This fact supported the effectiveness of the simple radiation method in estimation of evapotranspiration. The ratio of Tr/ET as well as the ratio of ground heat flux (G) to Rs (G/Rs) was closely related to LAI, and LAI was a key variable in determining the energy partitioning to soil and vegetation. It was clearly shown that a remotely sensed vegetation index such as SAVI (soil adjusted vegetation index) was effective for estimating LAI, and further useful for directly estimating energy partitioning to soil and vegetation. The G and Tr/ET were both well estimated by the vegetation index. It was concluded that the combination of a simple radiation method with remotely sensed information can provide useful information on energy partitioning and Tr/ET in vegetation canopies

  7. Radiometric Inter-Calibration between Himawari-8 AHI and S-NPP VIIRS for the Solar Reflective Bands

    OpenAIRE

    Fangfang Yu; Xiangqian Wu

    2016-01-01

    The Advanced Himawari Imager (AHI) on-board Himawari-8, which was launched on 7 October 2014, is the first geostationary instrument housed with a solar diffuser to provide accurate onboard calibrated data for the visible and near-infrared (VNIR) bands. In this study, the Ray-matching and collocated Deep Convective Cloud (DCC) methods, both of which are based on incidently collocated homogeneous pairs between AHI and Suomi NPP (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS), are used...

  8. The achievements of solar children from the natural created octave whose source is the emanating sun reflected by the Foundation for Solar Achievement with the Arts

    Energy Technology Data Exchange (ETDEWEB)

    Petacchi, D.V. [Foundation for Solar Achievement with the Arts, Hobart, NY (United States)

    1997-12-31

    The Foundation for Solar Achievement With The Arts is a not-for-profit school training gifted children in the use of their talent in accordance with the philosophy and experience that children in harmony with their natural environment based upon the sun`s position in the course of the day have the greater capacity of attention necessary to enhance learning and creativity. Uncluttered as much as possible by the distractions of technology or the artificial glare of electricity, the learning environment of the Foundation for Solar Achievement With The Arts is conducive to this hands-on action. The Foundation was started by an individual whose life long search for the meaning of his life and whose pondering on the meaning human life on this planet led him to many conclusions modern science is just beginning to reach. With the help of dedicated architect John Jehring and likeminded others, Mr. Petacchi is utilizing natural sunlight in an environment conducive to the psyche of children. A building is planned that will expand into indoor form the natural lighting and free space of the out-of-doors.

  9. The achievements of solar children from the natural created octave whose source is the emanating sun reflected by the Foundation for Solar Achievement with the Arts

    International Nuclear Information System (INIS)

    The Foundation for Solar Achievement With The Arts is a not-for-profit school training gifted children in the use of their talent in accordance with the philosophy and experience that children in harmony with their natural environment based upon the sun's position in the course of the day have the greater capacity of attention necessary to enhance learning and creativity. Uncluttered as much as possible by the distractions of technology or the artificial glare of electricity, the learning environment of the Foundation for Solar Achievement With The Arts is conducive to this hands-on action. The Foundation was started by an individual whose life long search for the meaning of his life and whose pondering on the meaning human life on this planet led him to many conclusions modern science is just beginning to reach. With the help of dedicated architect John Jehring and likeminded others, Mr. Petacchi is utilizing natural sunlight in an environment conducive to the psyche of children. A building is planned that will expand into indoor form the natural lighting and free space of the out-of-doors

  10. Measurement of the radial velocity of the Sun as a star by means of a reflecting solar system body. The effect of the body rotation

    CERN Document Server

    Lanza, A F

    2015-01-01

    Minor bodies of the solar system can be used to measure the spectrum of the Sun as a star by observing sunlight reflected by their surfaces. To perform an accurate measurement of the radial velocity of the Sun as a star by this method, it is necessary to take into account the Doppler shifts introduced by the motion of the reflecting body. Here we discuss the effect of its rotation. It gives a vanishing contribution only when the inclinations of the body rotation axis to the directions of the Sun and of the Earth observer are the same. When this is not the case, the perturbation of the radial velocity does not vanish and can reach up to about 2.4 m/s for an asteroid such as 2 Pallas that has an inclination of the spin axis to the plane of the ecliptic of about 30 degrees. We introduce a geometric model to compute the perturbation in the case of a uniformly reflecting body of spherical or triaxial ellipsoidal shape and provide general results to easily estimate the magnitude of the effect.

  11. A novel pyrophosphate BaCr2(P2O7)2 as green pigment with high NIR solar reflectance and durable chemical stability

    Science.gov (United States)

    Tao, Zhengxu; Zhang, Wanqi; Huang, Yanlin; Wei, Donglei; Seo, Hyo Jin

    2014-08-01

    A novel pyrophosphate BaCr2(P2O7)2 was synthesized by the conventional solid-state reaction. The X-ray diffraction (XRD), FTIR spectrum, scanning electron microscopy (SEM) and ultraviolet-visible (UV-Vis) near infrared (NIR) reflectance spectra were applied to characterize the powders. The refractive indexes and nature of the VB and CB were determined. The structure, color properties and application were investigated. The results reveal that the anomalist bodies with smooth surfaces were obtained at 1200 °C with a mean size of 3 μm. A high reflectance peak at 535 nm was observed in the visible region, which is associated with the brilliant and deep green color of this pigment. With all the acids, alkali and deionized water treatment, the polycrystalline pigment BaCr2(P2O7)2 was found to be durable in chemical stability. The significantly high NIR solar reflectance of BaCr2(P2O7)2 is 90.0%, a higher cooling ability, so it has been selected to be tested as cool green pigment in ceramics. Moreover, this novel pyrophosphate pigment has great potential as cool pigment for surface coating applications.

  12. Preparation and Application of Automatic Photometric Titration Analyzer Based on Reflective Photometric Sensor%基于反射式光度传感器的自动光度滴定仪的研制及应用

    Institute of Scientific and Technical Information of China (English)

    何艺; 周小锋; 马建丰

    2012-01-01

    研制了一种以颜色变化为滴定终点的自动光度滴定仪,仪器以光度传感器为核心,包括光度探头、滴定装置、AT89S52单片机、电磁阀、二极管和磁力搅拌器等部件。传感器采用开放设计,对溶液吸光度变化反应迅速。仪器用于红醋酸度的测定,所得结果与电位滴定分析法结果相符。%An automatic photometric titration analyzer with color change as end point of titration was prepared. The analyzer consisted of reflective photometric sensor (as core), photometric probe, titration device, AT89S52 monolithic circuit, electromagnetic valve, diode and magnetic stirrer. The open design of sensor leaded to detect the absorbance of solution without delay in titration. The analyzer was applied in the determination of acidity of red vinegar, and the results obtained were in consistency with those obtained by potentiometric titration.

  13. Characterizing Cold Giant Planets in Reflected Light: Lessons from 50 Years of Outer Solar System Exploration and Observation

    Science.gov (United States)

    Marley, Mark Scott; Hammel, Heidi

    2014-01-01

    A space based coronagraph, whether as part of the WFIRST/AFTA mission or on a dedicated space telescope such as Exo-C or -S, will be able to obtain photometry and spectra of multiple gas giant planets around nearby stars, including many known from radial velocity detections. Such observations will constrain the masses, atmospheric compositions, clouds, and photochemistry of these worlds. Giant planet albedo models, such as those of Cahoy et al. (2010) and Lewis et al. (this meeting), will be crucial for mission planning and interpreting the data. However it is equally important that insights gleaned from decades of solar system imaging and spectroscopy of giant planets be leveraged to optimize both instrument design and data interpretation. To illustrate these points we will draw on examples from solar system observations, by both HST and ground based telescopes, as well as by Voyager, Galileo, and Cassini, to demonstrate the importance clouds, photochemical hazes, and various molecular absorbers play in sculpting the light scattered by solar system giant planets. We will demonstrate how measurements of the relative depths of multiple methane absorption bands of varying strengths have been key to disentangling the competing effects of gas column abundances, variations in cloud height and opacity, and scattering by high altitude photochemical hazes. We will highlight both the successes, such as the accurate remote determination of the atmospheric methane abundance of Jupiter, and a few failures from these types of observations. These lessons provide insights into technical issues facing spacecraft designers, from the selection of the most valuable camera filters to carry to the required capabilities of the flight spectrometer, as well as mission design questions such as choosing the most favorable phase angles for atmospheric characterization.

  14. Radiometric Stability Monitoring of the Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS) Reflective Solar Bands Using the Moon

    OpenAIRE

    Taeyoung Choi; Xi Shao; Changyong Cao; Fuzhong Weng

    2015-01-01

    The Suomi NPP (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) performs the scheduled lunar roll maneuver on a monthly basis. The lunar calibration coefficients and lunar F-factor are calculated by taking the ratio of the lunar observed radiance to the simulated radiance from the Miller and Turner (MT) lunar model. The lunar F-factor is also validated against that derived from the VIIRS Solar Diffuser (SD). The MT model-based lunar F-factors in general agree with SD F-factors. The Lu...

  15. Reflection and Conversion of Magneto-Gravity Waves in the Solar Chromosphere: Windows to the Upper Atmosphere

    CERN Document Server

    Newington, Marie

    2009-01-01

    The detection of upward propagating internal gravity waves in the Sun's chromosphere has recently been reported by Straus et al., who postulated that these may efficiently couple to Alfven waves in magnetic regions. This may be important in transporting energy to higher levels. Here we explore the propagation, reflection and mode conversion of linear gravity waves in a VAL C atmosphere, and find that even weak magnetic fields usually reflect gravity waves back downward as slow magnetoacoustic waves well before they reach the Alfven/acoustic equipartition height at which mode conversion might occur. However, for certain highly inclined magnetic field orientations in which the gravity waves manage to penetrate near or through the equipartition level, there can be substantial conversion to either or both upgoing Alfven and acoustic waves. Wave energy fluxes comparable to the chromospheric radiative losses are expected.

  16. Nonlinear reflection process of linearly-polarized, broadband Alfv\\'en waves in the fast solar wind

    CERN Document Server

    Shoda, Munehito

    2016-01-01

    Using one-dimensional numerical simulations, we study the elementary process of Alfv\\'{e}n wave reflection in a uniform medium, including nonlinear effects. In the linear regime, Alfv\\'{e}n wave reflection is triggered only by the inhomogeneity of the medium, whereas in the nonlinear regime, it can occur via nonlinear wave-wave interactions. Such nonlinear reflection (backscattering) is typified by decay instability. In most studies of decay instabilities, the initial condition has been a circularly polarized Alfv\\'{e}n wave. In this study we consider a linearly polarized Alfv\\'en wave, which drives density fluctuations by its magnetic pressure force. For generality, we also assume a broadband wave with a red-noise spectrum. In the data analysis, we decompose the fluctuations into characteristic variables using local eigenvectors, thus revealing the behaviors of the individual modes. Different from circular-polarization case, we find that the wave steepening produces a new energy channel from the parent Alfv\\...

  17. The distance temperature map as method to analyze the optical properties of Fresnel lenses and their interaction with multi-junction solar cells

    Science.gov (United States)

    Hornung, Thorsten; Kiefel, Peter; Nitz, Peter

    2015-09-01

    The optical efficiency of Fresnel lens based solar concentrators varies with the temperature of the Fresnel lens. The dependency of any quantity of interest (e.g. optical efficiency) on Fresnel lens temperature can be visualized by 2d color plots that simultaneously show it as a function of the distance between solar cell and Fresnel lens and as a function of Fresnel lens temperature. This visualization, which is called DTmap, strongly facilitates the analysis of the thermal behavior of a Fresnel lens and the optimization of module height. Based on DTmaps we reveal and discuss serveral details of the thermal behavior of silicone on glass (SOG) Fresnel lenses. In addition, the DTmap is shown for the efficiency of a system consisting of a Fresnel lens and a lattice matched three-junction and a four-junction solar cell. The results demonstrate that the interaction of the concentrator optics and the solar cell is not trivial and may also be studied using DTmaps.

  18. User's guide to HELIOS: A computer program for modeling the optical behavior of reflecting solar concentrators. Part 3: Appendices concerning HELIOS-code details

    Science.gov (United States)

    Vittitoe, C. N.; Biss, F.

    1981-09-01

    HELIOS is a flexible computer code for evaluating designs for central-receiver, parabolic-dish, and other reflecting solar-energy collector systems; for safety calculations on the threat to personnel and to the facility itself; for determination of how various input parameters alter the power collected; for design trade-offs; and for heliostat evaluations. Input variables include atmospheric transmission effects; reflector shape, surface, and suntracking errors; focusing and alignment strategies; receiver design; placement positions of the tower and mirrors; time-of-day and day-of-year for the calculation. Part III is a series of appendices giving code details for subroutine and function descriptions, how common blocks are used, sample jobstreams, and magnetic tape use within the code.

  19. Development of Tandem Amorphous/Microcrystalline Silicon Thin-Film Large-Area See-Through Color Solar Panels with Reflective Layer and 4-Step Laser Scribing for Building-Integrated Photovoltaic Applications

    OpenAIRE

    Chin-Yi Tsai; Chin-Yao Tsai

    2014-01-01

    In this work, tandem amorphous/microcrystalline silicon thin-film large-area see-through color solar modules were successfully designed and developed for building-integrated photovoltaic applications. Novel and key technologies of reflective layers and 4-step laser scribing were researched, developed, and introduced into the production line to produce solar panels with various colors, such as purple, dark blue, light blue, silver, golden, orange, red wine, and coffee. The highest module power...

  20. Oxygen analyzer

    Science.gov (United States)

    Benner, William H.

    1986-01-01

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  1. Reflecting Reflective Practice

    Science.gov (United States)

    Galea, Simone

    2012-01-01

    This paper demystifies reflective practice on teaching by focusing on the idea of reflection itself and how it has been conceived by two philosophers, Plato and Irigaray. It argues that reflective practice has become a standardized method of defining the teacher in teacher education and teacher accreditation systems. It explores how practices of…

  2. Monitoring and Assessing the 2012 Drought in the Great Plains: Analyzing Satellite-Retrieved Solar-Induced Chlorophyll Fluorescence, Drought Indices, and Gross Primary Production

    OpenAIRE

    Siheng Wang; Changping Huang; Lifu Zhang; Yi Lin; Yi Cen; Taixia Wu

    2016-01-01

    We examined the relationship between satellite measurements of solar-induced chlorophyll fluorescence (SIF) and several meteorological drought indices, including the multi-time-scale standard precipitation index (SPI) and the Palmer drought severity index (PDSI), to evaluate the potential of using SIF to monitor and assess drought. We found significant positive relationships between SIF and drought indices during the growing season (from June to September). SIF was found to be more sensitive ...

  3. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    Reflection has moved from the margins to the mainstream in supervision. Notions of reflection have become well established since the late 1980s. These notions have provided useful framing devices to help conceptualize some important processes in guidance and counseling. However, some applications...... previously associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier...... views of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that...

  4. A net decrease in the Earth's cloud plus aerosol reflectivity during the past 33 yr (1979–2011 and increased solar heating at the surface

    Directory of Open Access Journals (Sweden)

    J. R. Herman

    2012-12-01

    Full Text Available Measured upwelling radiances from Nimbus-7 SBUV, seven NOAA SBUV/2 and the AURA-OMI instruments have been used to calculate the 340 nm Lambertian Equivalent Reflectivity (LER of the Earth from 1979 to 2011 after applying a new common calibration. The 340 nm LER is highly correlated with cloud and aerosol cover because of the low surface reflectivity of the land and oceans (typically 2 to 6 RU, where 1 RU = 0.01 = 1.0% relative to the much higher reflectivity of clouds plus aerosols (typically 10 to 90 RU. Because of the nearly constant seasonal and long-term 340 nm surface reflectivity, the 340 nm LER can be used to estimate changes in cloud plus aerosol amount associated with seasonal and interannual variability and decadal climate change. The annual motion of the Intertropical Convergence Zone, episodic El Nino Southern Oscillation ENSO, and latitude dependent seasonal cycles are apparent in the LER time series. LER trend estimates from 5° zonal average and from 2° × 5° latitude × longitude time series show that there has been a global net decrease in cloud plus aerosol reflectivity. The decrease in global cos2 (latitude weighted average LER from 60° S to 60° N is 0.79 ± 0.03 RU over 33 yr, corresponding to a 3.6 ± 0.2% change in LER. Based on energy balance partitioning (Trenberth et al., 2009 this corresponds to an increase of 2.7 W m−2 of solar energy reaching the Earth's surface (an increase of 1.4% or 2.3 W m−2 absorbed by the surface, which is partially offset by an increase in longwave cooling to space. Most of the decreases in cloud reflectivity occur over land, with the largest decreases occurring over the US (−0.97 RU decade−1, Brazil (−0.9 RU decade−1, and Central Europe (−1.35 RU decade−1. There are reflectivity increases near the west coast of Peru and Chile (0.8 ± 0.1 RU decade−1 over parts of India, China, and Indochina, and

  5. The linear Fresnel lens solar concentrator: Transverse tracking error effects

    Science.gov (United States)

    Cosby, R. M.

    1977-01-01

    The solar concentration performance of a line focusing, flat base Fresnel lens in the presence of small transverse tracking errors was analyzed. Solar transmittance of the lens and focal plane imaging characteristics were evaluated. Transmission losses by reflectance and material absorption were also studied.

  6. Development of a Code to Analyze the Solar White-Light Images from the Kodaikanal Observatory: Detection of Sunspots, Computation of Heliographic Coordinates and Area

    Indian Academy of Sciences (India)

    Ragadeepika Pucha; K. M. Hiremath; Shashanka R. Gurumath

    2016-03-01

    Sunspots are the most conspicuous aspects of the Sun. They have a lower temperature, as compared to the surrounding photosphere; hence, sunspots appear as dark regions on a brighter background. Sunspots cyclically appear and disappear with a 11-year periodicity andare associated with a strong magnetic field ($\\sim$ 10^3 G) structure. Sunspots consist of a dark umbra, surrounded by a lighter penumbra. Study of umbra–penumbra area ratio can be used to give a rough idea as to how the convective energy of the Sun is transported from the interior, as the sunspot’s thermal structure is related to this convective medium. An algorithm to extract sunspots from the white-light solar images obtained from the Kodaikanal Observatory is proposed. This algorithm computes the radius and center of the solar disk uniquely and removes the limb darkening from the image. It also separates the umbra and computesthe position as well as the area of the sunspots. The estimated results are compared with the Debrecen photoheliographic results. It is shown that both area and position measurements are in quite good agreement.

  7. Reflecting on Cherenkov reflections

    OpenAIRE

    Fargion, D.; Gaug, M.; Oliva, P.

    2007-01-01

    Magic Telescope may observe and reveal at horizons lights from air-shower Cherenkov reflections. The ground, the sea, the cloudy sky (below the mountain) may reflect PeVs-EeV UHECR Cherenkov lights observable by MAGIC telescopes. Even rarest UHE neutrino skimming the atmosphere or skimming the Earth may induce upward-horizontal airshowers: a new Neutrino Astronomy. These fluorescence signals or the Cherenkov reflections in upper cloudy sky may flash in correlated BL-Lac or GRB shining at oppo...

  8. Ground truth data for test sites (SL-3). [solar radiation and thermal radiation brightness temperature measurements

    Science.gov (United States)

    1974-01-01

    Field measurements performed simultaneously with Skylab overpasses in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. The solar radiation region from 400 to 1300 nanometers and the thermal radiation region from 8 to 14 micrometer region were investigated. The measurements of direct solar radiation were analyzed for atmospheric optical depth; the total and reflected solar radiation were analyzed for target reflectivity. These analyses were used in conjunction with a radiative transfer computer program in order to calculate the amount and spectral distribution of solar radiation at the apertures of the EREP sensors. The instrumentation and techniques employed, calibrations and analyses performed, and results obtained are discussed.

  9. Electrochemical deposition of black nickel solar absorber coatings on stainless steel AISI316L for thermal solar cells

    OpenAIRE

    Lira-Cantú, Monica; Morales Sabio, Angel; Brustenga, Alex; Gómez-Romero, P.

    2005-01-01

    We report the electrochemical deposition of nanostructured nickel-based solar absorber coatings on stainless steel AISI type 316L. A sol–gel silica-based antireflection coating, from TEOS, was also applied to the solar surface by the dip-coating method. We report our initial results and analyze the influence of the stainless steel substrate on the final total reflectance properties of the solar absorber. The relation between surface morphology, observed by SEM and AFM, the comp...

  10. Solar thanksgiving; Solarer Erntedank

    Energy Technology Data Exchange (ETDEWEB)

    Zehner, Mike; Doll, Andreas [Hochschule Muenchen (Germany). Arbeitsgruppe PV-Systeme; Hammer, Annette [Oldenburg Univ. (Germany). Arbeitsgruppe Energiemeteorologie; Heesen, Henrik te [Meteocontrol GmbH, Augsburg (Germany). Forschungsprojekt zur Analyse von Fernueberwachungsmessdaten; Herbort, Volker [Meteocontrol GmbH, Augsburg (Germany). Bereich Data-Mining-Vorhaben; Mariani, Marco [Meteocontrol GmbH, Augsburg (Germany). Abt. PV Ertragsgutachten und Prognosen

    2012-03-09

    While the 'felt' weather in 2011 was quite rainy, it was in fact one of the five hottest years since 1881, with many sunshine hours. This is reflected in photovoltaic power generation in 2011. Many owners of PV systems were surprised to find record solar power generation figures. In many cases, even the best case scenarios were topped.

  11. 太阳热反射涂料颜填料选择关键技术研究%Study on Key Technology of Selection of Pigments and Fillers for Solar Heat Reflectant Coatings

    Institute of Scientific and Technical Information of China (English)

    李运德; 张惠英; 毛方桂; 黄晓峰

    2013-01-01

    The solar heat reflectance performance of various coatings prepared by use of different pigments and fillers was compared according to the test methods of GJB2502. 2 and ASTM C1549. The results showed that titanium diosde was the key pigment for white solar heat reflectant coatings, inorganic black cool pigment was the key pigment for grey solar heat reflectant coatings, and strong infrared reflectant inorganic cool pigments were the key pigments for color coatings.%采用GJB 2502.2和ASTM C1549测试方法表征了太阳光热发射涂料的太阳光反射性能.结果表明:白色太阳光反射涂料的关键颜料为二氧化钛,灰色太阳光反射涂料的关键颜料为无机黑冷颜料,而彩色太阳光反射涂料的关键颜料为强红外反射无机冷颜料.

  12. Development of Tandem Amorphous/Microcrystalline Silicon Thin-Film Large-Area See-Through Color Solar Panels with Reflective Layer and 4-Step Laser Scribing for Building-Integrated Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Chin-Yi Tsai

    2014-01-01

    Full Text Available In this work, tandem amorphous/microcrystalline silicon thin-film large-area see-through color solar modules were successfully designed and developed for building-integrated photovoltaic applications. Novel and key technologies of reflective layers and 4-step laser scribing were researched, developed, and introduced into the production line to produce solar panels with various colors, such as purple, dark blue, light blue, silver, golden, orange, red wine, and coffee. The highest module power is 105 W and the highest visible light transmittance is near 20%.

  13. Low-frequency ionospheric sounding with Narrow Bipolar Event lightning radio emissions: energy-reflectivity spectrum

    Directory of Open Access Journals (Sweden)

    A. R. Jacobson

    2008-06-01

    Full Text Available We analyze data on radio-reflection from the D-region of the lower ionosphere, retrieving the energy-reflection coefficient in the frequency range ~5–95 kHz. The data are the same as developed for a recent study of ionospheric-reflection height, and are based on recordings of powerful (multi-Gigawatt radio emissions from a type of narrow (~10 μs lightning discharge known as "Narrow Bipolar Events". The sequential appearance of first the groundwave signal, and then the ionospheric single-hop reflection signal, permits us to construct the energy-reflection ratio. We infer the energy reflection's statistical variation with solar zenith angle, angle-of-incidence, frequency, and propagation azimuth. There is also a marginally-significant response of the energy reflectivity to solar X-ray flux density. Finally, we review the relationship of our results to previous published reports.

  14. Development of Abrasion-Resistant Coating for Solar Reflective Films. Cooperative Research and Development Final Report, CRADA Number CRD-07-247

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-01

    The purpose of this CRADA is to develop an abrasion-resistant coating, suitable for use on polymeric-based reflective films (e.g., the ReflecTech reflective film), that allows for improved scratch resistance and enables the use of aggressive cleaning techniques (e.g., direct contact methods like brushing) without damaging the specular reflectance properties of the reflective film.

  15. Evaluation of reflection-type polarizers with natural and synthetic mica crystals in the soft x-ray region of 1 keV. Aiming to development of polarizing elements for analyzing magnetic properties of nanostructure

    International Nuclear Information System (INIS)

    To develop soft x-ray polarizers functioning in 1 keV region of where there is no available polarizing element so far, the performances of natural and synthetic mica single-crystals have been investigated using horizontally linearly polarized synchrotron radiation (SR). As the results of the reflection measurements, at the incident energy of 878 eV, the reflectances for s- and p-polarisation components of natural mica were approximately 1.8% and 0.022%, respectively, and then the polarizance which stands for the polarizing ability has been estimated to be over 0.99 at least. This indicates that natural mica works as a practical reflection-type polarizer at 878 eV. In addition, as a preliminary experiment, the reflectance of syntetic mica dependence of the incident energy was measured near 45 deg incidence using SR. As the result, we found that synthetic mica sufficiently has a potential for functioning as a polarizer. (author)

  16. Reflective Teaching

    Science.gov (United States)

    Farrell, Thomas S. C.

    2013-01-01

    Thomas Farrell's "Reflective Teaching" outlines four principles that take teachers from just doing reflection to making it a way of being. Using the four principles, Reflective Practice Is Evidence Based, Reflective Practice Involves Dialogue, Reflective Practice Links Beliefs and Practices, and Reflective Practice Is a Way of Life,…

  17. Solar Simulator

    Science.gov (United States)

    1981-01-01

    Oriel Corporation's simulators have a high pressure xenon lamp whose reflected light is processed by an optical system to produce a uniform solar beam. Because of many different types of applications, the simulators must be adjustable to replicate many different areas of the solar radiation spectrum. Simulators are laboratory tools for such purposes as testing and calibrating solar cells, or other solar energy systems, testing dyes, paints and pigments, pharmaceuticals and cosmetic preparations, plant and animal studies, food and agriculture studies and oceanographic research.

  18. A heat store indicates a solar system; Wo ein Speicher ist, ist eine Solaranlage

    Energy Technology Data Exchange (ETDEWEB)

    Banse, Stephanie

    2011-05-31

    The London consulting business BRG analyzes the European market of hot water systems. The result is a comprehensive data compilation reflecting the situation of the solar heat store market, which also allows conclusions on the development of solar thermal power in general.

  19. Reflection, Reflective Practice and Embodied Reflective Practice

    OpenAIRE

    Leigh, Jennifer S; Bailey, Richard

    2013-01-01

    Although widely employed in professional practice of all kinds, ‘reflection’ and ‘reflective practice’ can be considered ‘success words’. That is, they elicit positive and supportive responses and yet the concepts are vague, ill-defined, contradictory and reflective skills can be hard to teach. Using examples from education and somatic movement therapy, we argue that a purely analytical approach to reflective practice that involves reflecting on thoughts alone is likely to lead into a negativ...

  20. Reflection Coefficients.

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    1994-01-01

    Discusses and provides an example of reflectivity approximation to determine whether reflection will occur. Provides a method to show thin-film interference on a projection screen. Also applies the reflectivity concepts to electromagnetic wave systems. (MVL)

  1. Solar TErrestrial Relations Observatory-A (STEREO-A) and PRoject for On-Board Autonomy 2 (PROBA2) Quadrature Observations of Reflections of Three EUV Waves from a Coronal Hole

    Science.gov (United States)

    Kienreich, I. W.; Muhr, N.; Veronig, A. M.; Berghmans, D.; De Groof, A.; Temmer, M.; Vršnak, B.; Seaton, D. B.

    2013-08-01

    We investigate the interaction of three consecutive large-scale coronal waves with a polar coronal hole, simultaneously observed on-disk by the Solar TErrestrial Relations Observatory (STEREO)-A spacecraft and on the limb by the PRoject for On-Board Autonomy 2 (PROBA2) spacecraft on 27 January 2011. All three extreme ultraviolet (EUV) waves originate from the same active region, NOAA 11149, positioned at N30E15 in the STEREO-A field of view and on the limb in PROBA2. For the three primary EUV waves, we derive starting velocities in the range of ≈ 310 km s-1 for the weakest up to ≈ 500 km s-1 for the strongest event. Each large-scale wave is reflected at the border of the extended coronal hole at the southern polar region. The average velocities of the reflected waves are found to be smaller than the mean velocities of their associated direct waves. However, the kinematical study also reveals that in each case the ending velocity of the primary wave matches the initial velocity of the reflected wave. In all three events, the primary and reflected waves obey the Huygens-Fresnel principle, as the incident angle with ≈ 10° to the normal is of the same magnitude as the angle of reflection. The correlation between the speed and the strength of the primary EUV waves, the homologous appearance of both the primary and the reflected waves, and in particular the EUV wave reflections themselves suggest that the observed EUV transients are indeed nonlinear large-amplitude MHD waves.

  2. My Reflective Practice as Research.

    Science.gov (United States)

    Pereira, Marcia A.

    1999-01-01

    Using Schon's concepts and definition of reflective practice, this article elaborates a model used to analyze the author's own processes of "reflection-in-action" and "reflection-on-action" in teaching first-year architectural students. Emphasizes the importance of the concept of "role-frame" in informing the whole reflective process. (EV)

  3. USO DE LA ESPECTROSCOPÍA DE REFLECTANCIA EN EL INFRARROJO CERCANO PARA EL ANÁLISIS DE CALIDAD DE ENSILAJE DE MAÍZ Use of near infrared reflectance spectroscopy to analyze corn silage quality

    Directory of Open Access Journals (Sweden)

    Daniel Cozzolino

    2003-10-01

    Full Text Available La espectroscopía de reflectancia en el infrarrojo cercano (NIRS fue utilizada para predecir la composición química del ensilaje de maíz (Zea mays L. Doscientas muestras de un amplio rango de características físico - químicas y origen, fueron leídas en un equipo monocromador (NIRS 6500, NIRSystems, Silver Spring, Maryland¸ USA en el rango de longitudes de onda de 400 a 2500 nm, en reflectancia. Los coeficientes de determinación en calibración (R²cal y el error estándar de la validación cruzada (SECV fueron 0,94 (SECV: 0,74%, 0,94 (SECV: 0,54%, 0,91 (SECV: 1,8%, y 0,90 (SECV: 3,8% para MS, proteína cruda (PC, fibra detergente ácida (FDA y fibra detergente neutra (FDN en base materia seca. Los resultados demuestran el potencial del NIRS para el análisis de rutina del ensilaje de maíz para MS, PC, y FDA.Near infrared reflectance spectroscopy (NIRS was used to predict the chemical composition of corn silage samples (Zea mays L.. Two hundred samples of a wide range of both chemical characteristics and origins were scanned in a monocromator instrument (NIRS 6500, NIRSystems, Silver Spring, Maryland, USA over the wavelength range between 400 to 2500 nm, in reflectance mode. Calibration coefficients of determination (R²cal and standard error in cross validation (SECV were 0.94 (SECV: 0.74%, 0.94 (SECV: 0.54%, 0.91 (SECV: 1.8%, and 0.90 (SECV: 3.8% for DM, crude protein (CP, acid detergent fiber (ADF and neutral detergent fiber (NDF respectively, dry weight basis. The results demonstrate the potential of NIRS for the routine analysis of corn silage to determine DM, CP and ADF.

  4. Reflective writing: a management skill

    OpenAIRE

    Sen, B.A.

    2010-01-01

    Purpose – The purpose of this paper is to analyze students' reflective writing in terms of identifiable outcomes and explore students' thoughts on reflection and reflective writing as a process. Design/methodology/approach – A mixed methods approach is taken with a qualitative analysis of 116 written reflections from MA Librarianship studying management over an eight-month period. A quantitative statistical analysis assesses the relationships between reflective writing and a number of po...

  5. The optimization of triple layer anti-reflection coatings and its application on solar cells%三层减反射膜的模拟及其在太阳电池中的应用

    Institute of Scientific and Technical Information of China (English)

    宫臣; 张静全; 冯良桓; 武莉莉; 李卫; 黎兵; 曾广根; 王文武

    2013-01-01

    The anti-reflection coatings with the structure of Al2O3/H4/MgF2 triple layer were prepared with electron beam evaporation technology on the glass substrate. The transmittance and surface morphology of the films were examined. The anti-reflection coating structure was optimized considering AMI. 5 spectrum and the spectroscopy response band of CdS/CdTe thin film solar cells through TFCALC software simulation. Then the optimized anti-reflection coatings were prepared on the CdTe thin film solar cells. It was found that the quantum efficiency of solar cells with anti-reflection coatings increase by 7. 3% than without, and the photoelectric conversion efficiency increased from 12. 5% to 13. 3%.%使用减反射膜层是提高太阳电池短路电流密度进而提高电池转换效率的有效手段之一.针对CdTe薄膜太阳电池的光谱响应范围,基于AM1.5辐照光谱,优化设计了MgF2/H4/Al2O3结构的减反射薄膜,使用电子束蒸发技术制备了该减反射膜,使用椭圆偏振仪、紫外/可见分光光度计、原子力显微镜分别测量了所制备薄膜的光学性质和表面形貌,对比分析了膜系结构理论模拟与实验测量结果.结果表明,使用该减反射薄膜后,电池的量子效率提高了7.3%;光电转换效率从12.5%提高到13.3%.

  6. Y{sub 2}O{sub 3}: Eu{sup 3+}, Tb{sup 3+} spherical particles based anti-reflection and wavelength conversion bi-functional films: Synthesis and application to solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Hui [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); Ji, Ruonan [School of Physics, Northwest University, Xi’an 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); Han, Linzi; Hao, Yuanyuan; Sun, Qian [School of Physics, Northwest University, Xi’an 710069 (China); Zhang, Dekai [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); Fan, Jun [School of Chemical Engineering, Northwest University, Xi’an 710069 (China); Bai, Jintao [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); and others

    2015-04-25

    Highlights: • Eu{sup 3+} and Tb{sup 3+} co-doped Y{sub 2}O{sub 3} particles were successfully prepared. The as prepared particles can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. • Y{sub 2}O{sub 3} is not only a good photoluminescence host material, but also it has high corrosion resistivity, thermal stability, and transparency from violet to infrared light. Cooperated with SiO{sub 2} sols, it could realize a better anti-reflection property. • As a proof-of-concept application, the as prepared bi-functional films could effectively improve the photoelectric conversion efficiency by 0.23% compared to pure SiO{sub 2} AR coating film and 0.55% compared to glass. - Abstract: In this study, Eu{sup 3+} and Tb{sup 3+} co-doped Y{sub 2}O{sub 3} particles were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The chosen particles were added in the SiO{sub 2} sols to get anti-reflection (AR) and wavelength conversion bi-functional films. Careful investigations were carried out to find the optimum preparation conditions and proper morphology. SEM images showed that the particle sizes reduced as metal ion/urea ratio decreased. Additionally, the extracted particles turned from sphere to lamellar type when the deionized water, which was used as solvent, reduced to a certain extent. The mechanisms of the morphology formation and diversification were proposed as well. The as prepared materials can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. The spherical sample showed better luminescence performance than the one with lamellar morphology. In addition, the optical transmittance spectra indicated that the films adding spherical particles had better anti-reflective performance, and the best adding amount was 0.08 g. Finally, As a proof-of-concept application

  7. Impulsive solar X-ray bursts. III - Polarization, directivity, and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1977-01-01

    The paper presents the spectrum, directivity, and state of polarization of the bremsstrahlung radiation expected from a beam of high-energy electrons spiraling along radial magnetic field lines toward the photosphere. A Monte Carlo method is then described for evaluation of the spectrum, directivity, and polarization of X-rays diffusely reflected from stellar photospheres. The accuracy of the technique is evaluated through comparison with analytic results. The calculated characteristics of the incident X-rays are used to evaluate the spectrum, directivity, and polarization of the reflected and total X-ray fluxes. The results are compared with observations.

  8. Biophysical information in asymmetric and symmetric diurnal bidirectional canopy reflectance

    Science.gov (United States)

    Vanderbilt, Vern C.; Caldwell, William F.; Pettigrew, Rita E.; Ustin, Susan L.; Martens, Scott N.; Rousseau, Robert A.; Berger, Kevin M.; Ganapol, B. D.; Kasischke, Eric S.; Clark, Jenny A.

    1991-01-01

    The authors present a theory for partitioning the information content in diurnal bidirectional reflectance measurements in order to detect differences potentially related to biophysical variables. The theory, which divides the canopy reflectance into asymmetric and symmetric functions of solar azimuth angle, attributes asymmetric variation to diurnal changes in the canopy biphysical properties. The symmetric function is attributed to the effects of sunlight interacting with a hypothetical average canopy which would display the average diurnal properties of the actual canopy. The authors analyzed radiometer data collected diurnally in the Thematic Mapper wavelength bands from two walnut canopies that received differing irrigation treatments. The reflectance of the canopies varied with sun and view angles and across seven bands in the visible, near-infrared, and middle infrared wavelength regions. Although one of the canopies was permanently water stressed and the other was stressed in mid-afternoon each day, no water stress signature was unambiguously evident in the reflectance data.

  9. O+ ion beams reflected below the Martian bow shock: MAVEN observations

    Science.gov (United States)

    Masunaga, K.; Seki, K.; Brain, D. A.; Fang, X.; Dong, Y.; Jakosky, B. M.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.

    2016-04-01

    We investigate a generation mechanism of O+ ion beams observed above the Martian bow shock by analyzing ion velocity distribution functions (VDFs) measured by the Suprathermal and Thermal Ion Composition instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. In the solar wind near Mars, MAVEN often observes energetic O+ ion beams (~10 keV or higher). Accompanied with the O+ ion beam events, we sometimes observe characteristic ion VDFs in the magnetosheath: a partial ring distribution. The partial ring distribution corresponds to pickup ions with a finite initial velocity (i.e., not newborn pickup ions), and its phase space density is much smaller than that of local pickup O+ ions of the magnetosheath. Thus, the partial ring distribution is most likely produced by the reflection of pickup O+ ions precipitating from the upstream solar wind below the bow shock. After being injected into the magnetosheath from the solar wind, the precipitating O+ ions are subject to the significantly enhanced magnetic field in this region and start to gyrate around the guiding center of the plasma frame in the magnetosheath. Consequently, a part of precipitating O+ ions are reflected back to the solar wind, generating O+ beams in the solar wind. The beams direct quasi-sunward near the subsolar region but have large angle with respect to the sunward direction at high solar zenith angles (>50°). The reflected O+ beams are accelerated by the convection electric field of the solar wind and may escape Mars.

  10. INCREMENT OF EFFICIENCY OF SOLAR CELL, WITH CHANGE SHAPE AND SIZE OF SOLAR PENNAL

    OpenAIRE

    S.K. Yadav; K.L. Yadav

    2014-01-01

    -To increase the efficiency of solar system with the help of change shape and size of solar pennal and arrangement of solar cell. And falling of light energy absorbed by solar cells and also dependence of solar energy, efficiency of solar cell on the multireflections of light on the solar cells. We formed different-different shape and size of solar pennal efficiency of solar cell, the internal and external reflections of light occurs many times with high energetic beam of ligh...

  11. Vicarious Calibration Based Cross Calibration of Solar Reflective Channels of Radiometers Onboard Remote Sensing Satellite and Evaluation of Cross Calibration Accuracy through Band-to-Band Data Comparisons

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-04-01

    Full Text Available Accuracy evaluation of cross calibration through band-to-band data comparison for visible and near infrared radiometers which onboard earth observation satellites is conducted. The conventional cross calibration for visible to near infrared radiometers onboard earth observation satellites is conducted through comparisons of band-to-band data of which spectral response functions are overlapped mostly. There are the following major error sources due to observation time difference, spectral response function difference in conjunction of surface reflectance and atmospheric optical depth, observation area difference. These error sources are assessed with dataset acquired through ground measurements of surface reflectance and optical depth. Then the accuracy of the conventional cross calibration is evaluated with vicarious calibration data. The results show that cross calibration accuracy can be done more precisely if the influences due to the aforementioned three major error sources are taken into account.

  12. Optical models for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, T.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    Light trapping is an important design feature for high-efficiency silicon solar cells. Because light trapping can considerably enhance optical absorption, a thinner substrate can be used which, in turn, can lower the bulk carrier recombination and concommitantly increase open-circuit voltage, and fill factor of the cell. The basic concepts of light trapping are similar to that of excitation of an optical waveguide, where a prism or a grating structure increases the phase velocity of the incoming optical wave such that waves propagated within the waveguide are totally reflected at the interfaces. Unfortunately, these concepts break down because the entire solar cell is covered with such a structure, making it necessary to develop new analytical approaches to deal with incomplete light trapping in solar cells. This paper describes two models that analyze light trapping in thick and thin solar cells.

  13. Solar Thermal Rocket Propulsion

    Science.gov (United States)

    Sercel, J. C.

    1986-01-01

    Paper analyzes potential of solar thermal rockets as means of propulsion for planetary spacecraft. Solar thermal rocket uses concentrated Sunlight to heat working fluid expelled through nozzle to produce thrust.

  14. Reflection groups

    International Nuclear Information System (INIS)

    In 2005, PISA organised proactive meetings of reflection groups on involvement in decision making, expert culture and ethical aspects of radiation protection.All reflection group meetings address particular targeted audiences while the output publication in book form is put forward

  15. Solar concentration by curved-base Fresnel lenses

    Science.gov (United States)

    Cosby, R. M.

    1977-01-01

    The solar concentration performance of idealized curved base line focusing Fresnel lenses is analyzed. A simple optical model was introduced to study the effects of base curvature and lens f-number. Thin lens ray tracing and the laws of reflection and refraction are used to develop expression for lens transmittance and image plane intensity profiles. The intensity distribution over the solar spectrum, lens dispersion effects, and absorption by the lens material are included in the analysis. Model capabilities include assessment of lens performance in the presence of small transverse tracking errors and the sensitivity of solar image characteristics to focusing.

  16. Portable flash lamp reflectance analyzer system and method

    Science.gov (United States)

    Kalshoven, James Edward (Inventor)

    1999-01-01

    The system and method allow spectroscopic analysis of vegetation or the like without effects from changing sun and cloud conditions, undesired portions of the area of interest or atmospheric disturbances. The system (1) includes a light source (5) such as a xenon flash lamp, a telescope (7), a spectrometer (9), an analog/digital converter (11), a memory (13), a display (15), and an on-board microprocessor (17) or a port (19) for attachment to a laptop computer. The system is taken to an area of interest in the woods (step 41), the vegetation is illuminated from below (step 43) and data are taken (step 45).

  17. Quantifying Reflection

    DEFF Research Database (Denmark)

    Alcock, Gordon Lindsay

    2013-01-01

    This paper documents 1st semester student reflections on “learning to learn” in a team-based PBL environment with quantitative and qualitative student reflective feedback on the learning gains of 60 Architectural Technology and Construction Management students at VIA University College, Denmark. It...... contrasts the students’ self-assessment in a range of ‘product’ skills such as Revit, Structural Design, Mathematics of construction, Technical Installations; as well as ‘process’ competencies such as ‘Working in a team’, Sharing knowledge, Maintaining a portfolio and Reflecting ON learning and FOR learning...

  18. Design Multilayer Antireflection Coatings for Terrestrial Solar Cells

    Directory of Open Access Journals (Sweden)

    Feng Zhan

    2014-01-01

    Full Text Available In order to analyze the influence of methods to design antireflection coatings (ARCs on reflectivity of broadband solar cells, we provide detailed analyses about the ARC coupled with a window layer and the refractive index dispersion effect of each layer. By multidimensional matrix data simulation, two methods were employed to measure the composite reflection of a SiO2/ZnS double-layer ARC within the spectral ranges of 300–870 nm (dual junction and 300–1850 nm (triple junction under AM1.5 solar radiation. A comparison study, between the results obtained from the commonly used weighted average reflectance method (WAR and that from the introduced effective average reflectance method (EAR, shows that the optimization of ARC by EAR method is convenient and feasible.

  19. Comparison of sensorless dimming control based on building modeling and solar power generation

    International Nuclear Information System (INIS)

    Artificial lighting in office buildings accounts for about 30% of the total building energy consumption. Lighting energy is important to reduce building energy consumption since artificial lighting typically has a relatively large energy conversion factor. Therefore, previous studies have proposed a dimming control using daylight. When applied dimming control, method based on building modeling does not need illuminance sensors. Thus, it can be applied to existing buildings that do not have illuminance sensors. However, this method does not accurately reflect real-time weather conditions. On the other hand, solar power generation from a PV (photovoltaic) panel reflects real-time weather conditions. The PV panel as the sensor improves the accuracy of dimming control by reflecting disturbance. Therefore, we compared and analyzed two types of sensorless dimming controls: those based on the building modeling and those that based on solar power generation using PV panels. In terms of energy savings, we found that a dimming control based on building modeling is more effective than that based on solar power generation by about 6%. However, dimming control based on solar power generation minimizes the inconvenience to occupants and can also react to changes in solar radiation entering the building caused by dirty window. - Highlights: • We conducted sensorless dimming control based on solar power generation. • Dimming controls using building modeling and solar power generation were compared. • The real time weather conditions can be considered by using solar power generation. • Dimming control using solar power generation minimizes inconvenience to occupants

  20. Imaging of a Transitional Disk Gap in Reflected Light: Indications of Planet Formation Around the Young Solar Analog LkCa 15

    CERN Document Server

    Thalmann, C; Goto, M; Wisniewski, J P; Janson, M; Henning, T; Fukagawa, M; Honda, M; Mulders, G D; Min, M; Moro-Martín, A; McElwain, M W; Hodapp, K W; Carson, J; Abe, L; Brandner, W; Egner, S; Feldt, M; Fukue, T; Golota, T; Guyon, O; Hashimoto, J; Hayano, Y; Hayashi, M; Hayashi, S; Ishii, M; Kandori, R; Knapp, G R; Kudo, T; Kusakabe, N; Kuzuhara, M; Matsuo, T; Miyama, S; Morino, J -I; Nishimura, T; Pyo, T -S; Serabyn, E; Shibai, H; Suto, H; Suzuki, R; Takami, M; Takato, N; Terada, H; Tomono, D; Turner, E L; Watanabe, M; Yamada, T; Takami, H; Usuda, T; Tamura, M

    2010-01-01

    We present H- and Ks-band imaging data resolving the gap in the transitional disk around LkCa 15, revealing the surrounding nebulosity. We detect sharp elliptical contours delimiting the nebulosity on the inside as well as the outside, consistent with the shape, size, ellipticity, and orientation of starlight reflected from the far-side disk wall, whereas the near-side wall is shielded from view by the disk's optically thick bulk. We note that forward-scattering of starlight on the near-side disk surface could provide an alternate interpretation of the nebulosity. In either case, this discovery provides confirmation of the disk geometry that has been proposed to explain the spectral energy distributions (SED) of such systems, comprising an optically thick outer disk with an inner truncation radius of ~46 AU enclosing a largely evacuated gap. Our data show an offset of the nebulosity contours along the major axis, likely corresponding to a physical pericenter offset of the disk gap. This reinforces the leading...

  1. Reflective optics

    CERN Document Server

    Korsch, Dietrich

    1991-01-01

    This is the first book dedicated exclusively to all-reflective imaging systems. It is a teaching tool as well as a practical design tool for anyone who specializes in optics, particularly for those interested in telescopes, infrared, and grazing-incidence systems. The first part of the book describes a unified geometric optical theory of all-reflective imaging systems (from near-normal to grazing incidence) developed from basic principles. The second part discusses correction methods and a multitude of closed-form solutions of well-corrected systems, supplemented with many conventional and unc

  2. Analyzing Tibetan Monastics Conception of Universe Through Their Drawings

    Science.gov (United States)

    Sonam, Tenzin; Chris Impey

    2016-06-01

    Every culture and tradition has their own representation of the universe that continues to evolve through new technologies and discoveries, and as a result of cultural exchange. With the recent introduction of Western science into the Tibetan Buddhist monasteries in India, this study explores the monastics’ conception of the universe prior to their formal instruction in science. Their drawings were analyzed using Tversky’s three criteria for drawing analysis namely—segmentation, order, and hierarchical structure of knowledge. Among the sixty Buddhist monastics included in this study, we find that most of them draw a geocentric model of the universe with the Solar System as the dominant physical system, reflecting little influence of modern astronomical knowledge. A few monastics draw the traditional Buddhist model of the world. The implications of the monastics' representation of the universe for their assimilation of modern science is discussed.

  3. Research on Flat Solar Collector

    OpenAIRE

    Kavolynas, Antanas

    2005-01-01

    The Thesis analyzes one of the spheres of alternative energy supply – the solar energy. The main objective of the Thesis is to determine the energy rates of the solar collector and its accumulative capacity. The Paper introduces a stand on the solar collector research which consists of a flat solar collector, heat accumulator and auxiliary equipment. The research object of the Thesis is a laboratory flat solar collector and its system. The Thesis analyses the constructions of the solar collec...

  4. 太阳帆悬浮轨道的动力学特性分析%Analyzing dynamic characteristics of the displaced orbit above a planet with solar sail

    Institute of Scientific and Technical Information of China (English)

    陈翠红; 和兴锁; 宋明

    2013-01-01

    研究了太阳帆悬浮轨道的动力学特性,主要分析了稳定性条件.首先建立垂直于太阳-行星连线的悬浮轨道模型,在柱坐标系下,依据Hamilton原理得到悬浮轨道角动量与太阳光压的关系.然后,针对小扰动情况运动方程,分析悬浮轨道线性与非线性稳定性条件.最后,运用Hamilton-Jacobi理论进行变量分离,得到物理意义明显的动力学方程.仿真结果表明,选取合适的初始值,可以实现稳定的太阳帆悬浮轨道.%This article studies kinetic characteristic of solar sail displaced orbit and analyses stability conditions. Firstly,by establishing displaced orbit model which is normal to sun-planet and assuming solar radiation pressure as constant,the relationship between displaced orbit angular momentum and solar radiation pressure can be derived through Hamilton dynamics method. Considering small perturbations of motion equation,the stability condition of linear and nonlinear displaced orbit can be derived. Finally,u-sing Hamilton-Jacobi theory,the kinetic equation with significance physical meaning can be derived by variable separation. Simulation results show that stable solar sail displaced orbit can be realized by choosing proper initial value.

  5. Thermal Stress Analysis of Two-stage Reflective Tower Solar Heat Absorber%二次反射塔式太阳能吸热器热应力分析

    Institute of Scientific and Technical Information of China (English)

    张晨; 马超; 赵云云; 李凤娟; 张晓燕; 杨晓峰

    2015-01-01

    Solar energy heat absorber is one of the most important equipment in tower thermal solar energy systems ,the heat pipe and the joint of heat pipe and mother tube are the thermal stress concentration. This paper analyze thermal stress of these parts in heat absorber. Numerical simulation is used to get the change of the thermal stress of different bend with the temperature change. The results prove that the temperature difference of molten salt is the main factor which influences the thermal stress distribution can be got.%太阳能吸热器是塔式光热太阳能发电系统中最重要的设备之一,吸热器内吸热管、吸热管与母管连接处都是热应力产生的集中点,文中对吸热器这几个部位进行热应力分析,通过数值模拟得出不同弯头热应力随温度的变化情况,以及熔盐温差是影响热应力分布的主要因素。

  6. Selectively reflective transparent sheets

    Science.gov (United States)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  7. A experiência de uma formadora de professores de Química: analisando suas ações e reflexões num curso de educação continuada The experience of a Chemistry teacher educator: analyzing their actions and reflections in a continuing education course

    Directory of Open Access Journals (Sweden)

    Maisa Helena Altarugio

    2010-01-01

    Full Text Available Objetivou-se analisar a experiência de uma formadora num curso de formação continuada para professores de Química, ocorrido numa universidade pública do estado de São Paulo, em 2004. Os dados apresentados surgiram da observação da prática da formadora e de suas reflexões, nas quais ela própria evidencia ideias, conflitos, angústias e impressões sobre suas ações durante o curso. Entre a prática da formadora e suas reflexões, surgem contrastes que irão se tornar nosso foco de investigação. Interpretamos esses contrastes como a atuação de elementos inconscientes que ora favorecem ora dificultam a sua prática e nos mostram que nem sempre a reflexão e a ação atuam na mesma direção. Defendemos uma prática reflexiva mais profunda e questionadora dos sujeitos como possibilidade para produzir melhores efeitos na formação e na atividade docente. Conceitos do referencial teórico psicanalítico de Freud e Lacan serviram de base para a análise dos dados.This paper is meant to analyze a teacher educator's experience when giving a continuing education course for chemistry teachers, held at a public university in São Paulo, in 2004. The information here has resulted from the observation of the teacher educator's performance and her reflections on their own ideas, conflicts, anguish and impressions concerning her actions throughout the course. The contrasts between the educator's practice and her reflections are the focus of this study. Such contrasts are regarded as a result of the presence of unconscious elements that either favor or hinder practice, and show that reflection and action not always lead to the same direction. We believe individuals should be encouraged to take a more questioning and more reflective attitude, enabling better results in teachers' education as well as more effective performance. Data analysis was based on concepts belonging to Freud's and Lacan's psychoanalytic theories.

  8. IIP Tropospheric Infrared Mapping Spectrometers (TIMS) demonstration of CO retrieval, including multi-layer, from atmospheric data acquired simultaneously in the solar reflective region near 2.3 um and the thermal emissive region near 4.7 um

    Science.gov (United States)

    Mergenthaler, J. L.; Kumer, J.; Roche, A. E.; Rairden, R. L.; Blatherwick, R.; Hawat, T.; Desouza-Machado, S.; Hannon, S.; Chatfield, R. B.

    2008-12-01

    The NASA Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) Tropospheric Infrared Mapping Spectrometers (TIMS) have been developed to demonstrate measurement capability, when deployed in space, for multi-layer retrieval of CO from spectral measurements acquired in the solar reflective (SR) region ~ 4281 to 4301 cm-1 and in the thermal InfraRed (TIR) region ~ 2110 to 2165 cm-1. We describe joint deployment at Denver University (DU) with co-investigators there of the TIMS, and of the DU colleagues FTS, to acquire simultaneous measurements of atmospheric spectra in the SR and the TIR. The FTS provided validation radiance data for the TIMS. The TIMS retrievals of CO, H2O and CH4 agreed well with validation vs these as retrieved from the DU data, AIRS retrieval, standard models and ECMWF. The TIMS CO retrievals included column retrieved from the just the SR data, column retrieved from just the TIR data, and a simple two-layer retrieval from the combined data sets. The data were acquired in an operational mode that mimicked the operations in a conceptual application that would provide footprints, coverage, refresh time as in the Decadal Survey GEO-CAPE mission statement. Very encouraging CO precisions were achieved, e.g., the TIMS CO column retrieval from the SR data demonstrated better than the 10% precision requirement as listed on slide 32 of the GEO-CAPE Reference document http://geo- cape.larc.nasa.gov/docs/GEOMAC_FinalReport_no_costs.ppt

  9. The nature of the solar activity during the Maunder Minimum revealed by the Guliya ice core record

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Whether the solar activity was very low, and especially whether the solar cycle existed, during the Maunder Minimum (1645-1715 AD), have been disputed for a long time. In this paper we use the Guliya NO3- data, which can reflect the solar activity, to analyze the characteristics of the solar activity during the Maunder Minimum. The results show that the solar activity was indeed low, and solar cycle displayed normal as present, i.e. about 11a, in that period. Moreover, it was found that the solar activity contains a 36-year periodic component probably, which might be related to the variations in the length of the sunspot cycle. This finding is of importance for the study of the relationship between the sun variability and the Earth climate change.

  10. Solar receiver with integrated optics

    Science.gov (United States)

    Jiang, Lun; Winston, Roland

    2012-10-01

    The current challenge for PV/Thermal (PV/T) systems is the reduction of radiation heat loss. Compared to solar thermal selective coating, the solar cells cannot be used as an efficient thermal absorber due to their large emissivity of the encapsulation material. Many commercial PV/T products therefore require a high concentration (more than 10x) to reach an acceptable thermal efficiency for their receivers. Such a concentration system inevitably has to track or semi-track, which induces additional cost and collects only the direct radiation from the sun. We propose a new PV/T design using a vacuum encapsulated thin film cell to solve this problem. The proposed design also collects the diffuse sun light efficiently by using an external compound parabolic concentrator (XCPC). Since the transparent electrode (TCO) of thin film cell is inherently transparent in visible light and reflective beyond infrared, this design uses this layer instead of the conventional solar cell encapsulation as the outmost heat loss surface. By integrating such a vacuum design with a tube shaped absorber, we reduce the complexity of conducting the heat energy and electricity out of the device. A low concentration standalone non-tracking solar collector is proposed in this paper. We also analyzed the thermosyphon system configuration using heat transfer and ray tracing models. The economics of such a receiver are presented.

  11. Analyzing in the Present

    DEFF Research Database (Denmark)

    Revsbæk, Line; Pedersen, Lene Tanggaard

    2015-01-01

    The article presents a notion of “analyzing in the present” as a source of inspiration in analyzing qualitative research materials. The term emerged from extensive listening to interview recordings during everyday commuting to university campus. Paying attention to the way different parts of...... various interviews conveyed diverse significance to the listening researcher at different times became a method of continuously opening up the empirical material in a reflexive, breakdown-oriented process of analysis. We argue that situating analysis in the present of analyzing emphasizes and acknowledges...... contributes to an ongoing methodological conversation problematizing the notion of “data” and the use of “data-reliant” methods of analysis....

  12. Solar energy modulator

    Science.gov (United States)

    Hale, R. R. (Inventor); Mcdougal, A. R.

    1984-01-01

    A module is described with a receiver having a solar energy acceptance opening and supported by a mounting ring along the optic axis of a parabolic mirror in coaxial alignment for receiving solar energy from the mirror, and a solar flux modulator plate for varying the quantity of solar energy flux received by the acceptance opening of the module. The modulator plate is characterized by an annular, plate-like body, the internal diameter of which is equal to or slightly greater than the diameter of the solar energy acceptance opening of the receiver. Slave cylinders are connected to the modulator plate for supporting the plate for axial displacement along the axis of the mirror, therby shading the opening with respect to solar energy flux reflected from the surface of the mirror to the solar energy acceptance opening.

  13. Miniature mass analyzer

    CERN Document Server

    Cuna, C; Lupsa, N; Cuna, S; Tuzson, B

    2003-01-01

    The paper presents the concept of different mass analyzers that were specifically designed as small dimension instruments able to detect with great sensitivity and accuracy the main environmental pollutants. The mass spectrometers are very suited instrument for chemical and isotopic analysis, needed in environmental surveillance. Usually, this is done by sampling the soil, air or water followed by laboratory analysis. To avoid drawbacks caused by sample alteration during the sampling process and transport, the 'in situ' analysis is preferred. Theoretically, any type of mass analyzer can be miniaturized, but some are more appropriate than others. Quadrupole mass filter and trap, magnetic sector, time-of-flight and ion cyclotron mass analyzers can be successfully shrunk, for each of them some performances being sacrificed but we must know which parameters are necessary to be kept unchanged. To satisfy the miniaturization criteria of the analyzer, it is necessary to use asymmetrical geometries, with ion beam obl...

  14. Software Design Analyzer System

    Science.gov (United States)

    Tausworthe, R. C.

    1985-01-01

    CRISP80 software design analyzer system a set of programs that supports top-down, hierarchic, modular structured design, and programing methodologies. CRISP80 allows for expression of design as picture of program.

  15. Corrosion resistant solar mirror

    Energy Technology Data Exchange (ETDEWEB)

    Medwick, Paul A.; Abbott, Edward E.

    2016-07-19

    A reflective article includes a transparent substrate having a first major surface and a second major surface. A base coat is formed over at least a portion of the second major surface. A primary reflective coating having at least one metallic layer is formed over at least a portion of the base coat. A protective coating is formed over at least a portion of the primary reflective coating. The article further includes a solar cell and an anode, with the solar cell connected to the metallic layer and the anode.

  16. Dynamics of the Solar Plasma Events and Their Interplanetary Consequences

    Science.gov (United States)

    Kaushik, Subhash Chandra

    2016-07-01

    In the present study we have analyzed the interplanetary plasma / field parameter, which have initiated the complex nature intense and highly geo-effective events in the magnetosphere. It is believed that Solar wind velocity V. interplanetary magnetic field (IMF) B and Bz are the crucial drivers of these activities. However, sometimes strong geomagnetic disturbance is associated with the interaction between slow and fast solar wind originating from coronal holes leads to create co-rotating plasma interaction region (CIR). Thus the dynamics of the magnetospheric plasma configuration is the reflection of measured solar wind and interplanetary magnetic field (IMF) conditions. While the magnetospheric plasma anomalies are generally represented by geomagnetic storms and sudden ionosphere disturbance (SIDs). The study considers geomagnetic storms associated with disturbance storm time (Dst) decreases of more than -50 nT to -300 nT, observed during solar cycle 23 and the ascending phase of solar cycle 24. These have been analyzed and studied statistically. The spacecraft data those provided by SOHO, ACE and geomagnetic stations like WDC-Kyoto are utilized in the study. It is observed that the yearly occurrences of geomagnetic storm are strongly correlated with 11-year sunspot cycle, but no significant correlation between the maximum and minimum phase of solar cycle have been found. It is also found that solar cycle-23 is remarkable for occurrence of intense geomagnetic storms during its declining phase. The detailed results are discussed in this paper.

  17. Inspiring Reflections

    DEFF Research Database (Denmark)

    Muchie, Mammo

    2011-01-01

    life is not free from fluctuations, cycles, disruptions, crises and destructions both human and ecological. Innovation research ought to position itself to address environmental, financial and economic crises. The third is innovation research for development by addressing not only poverty erdaication......A numberof Chris Freeman's colleagues were asked to reflect on what they thought describes his life and work in a few words. Some of the colleagues replied including former SPRU students that were taught or supervised by Chris Freeman. Their views on what they thought were Chris Freeman's defining...... contributions have been put together. There are a number of ways to continue Chris Freeman's legacy on innovation research. The first is to build in a critical tradition in the economics of innovation research by introducing fearlessly emancipatory epistemology. Second the economic system that dominates social...

  18. The temporal dynamics of calibration target reflectance

    OpenAIRE

    Anderson, K.; Milton, E. J.; Rollin, E.M.

    2003-01-01

    A field experiment investigated the hypothesis that the nadir reflectance of calibration surface substrates (asphalt and concrete) remains stable over a range of time-scales. Measurable differences in spectral reflectance factors were found over periods as short as 30 minutes. Surface reflectance factors measured using a dual-field-of-view GER1500 spectroradiometer system showed a relationship with the relative proportion of diffuse irradiance, over periods when solar zenith changes were m...

  19. Solar Control Glazing for Trucks

    OpenAIRE

    Tavast, Johan

    2007-01-01

    This thesis concerns the use of solar control and electrochromic glazing in trucks. The purpose has been to study the decrease in solar energy transport into the cab and how to utilize the technology. The solar spectrum consists of both visible light and near-IR radiation, and solar control glazing transmits the majority of the visible light and reflects or absorbs most of the near-IR radiation. Electrochromic glazing has variable transmittance, which enables the driver to regulate the energy...

  20. Total organic carbon analyzer

    Science.gov (United States)

    Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

  1. Reflective Practice on Effective Teaching Performance

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-chao

    2014-01-01

    Reflective practice is a vital parts of teaching process. The essay mainly states the theory of reflection, its functions, characteristics, and teachers’reflective practice. After obtaining data from the questionnaire collected from 30 college English teachers’reflective practice, the writer analyzes the data and concludes that:reflection is a useful and necessary tool for successful teaching performance and the development of teachers.

  2. Ground truth data for test sites (SL-4). [thermal radiation brightness temperature and solar radiation measurments

    Science.gov (United States)

    1974-01-01

    Field measurements performed simultaneous with Skylab overpass in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. Wavelength region covered include: solar radiation (400 to 1300 nanometer), and thermal radiation (8 to 14 micrometer). Measurements consisted of general conditions and near surface meteorology, atmospheric temperature and humidity vs altitude, the thermal brightness temperature, total and diffuse solar radiation, direct solar radiation (subsequently analyzed for optical depth/transmittance), and target reflectivity/radiance. The particular instruments used are discussed along with analyses performed. Detailed instrument operation, calibrations, techniques, and errors are given.

  3. Application of solar energy

    OpenAIRE

    Li, Jingcheng

    2010-01-01

    The purpose of the project is to learn the principle and application of solar energy and to know the situation of solar energy in China and build a solar farm in China . In the theoretical part of the project the main issue was to find out how to collect the solar energy and how to store solar energy. The information of the project was collected by using network and books. This work was completed in the following steps : to search information for the theory part, to analyze the data ...

  4. List mode multichannel analyzer

    Science.gov (United States)

    Archer, Daniel E.; Luke, S. John; Mauger, G. Joseph; Riot, Vincent J.; Knapp, David A.

    2007-08-07

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  5. Centrifugal analyzer development

    International Nuclear Information System (INIS)

    The development of the centrifuge fast analyzer (CFA) is reviewed. The development of a miniature CFA with computer data analysis is reported and applications for automated diagnostic chemical and hematological assays are discussed. A portable CFA system with microprocessor was adapted for field assays of air and water samples for environmental pollutants, including ammonia, nitrates, nitrites, phosphates, sulfates, and silica. 83 references

  6. Analyzed Using Statistical Moments

    International Nuclear Information System (INIS)

    Diffraction enhanced imaging (DEl) technique is a new x-ray imaging method derived from radiography. The method uses a monorheumetten x-ray beam and introduces an analyzer crystal between an object and a detector Narrow angular acceptance of the analyzer crystal generates an improved contrast over the evaluation radiography. While standart radiography can produce an 'absorption image', DEl produces 'apparent absorption' and 'apparent refraction' images with superior quality. Objects with similar absorption properties may not be distinguished with conventional techniques due to close absorption coefficients. This problem becomes more dominant when an object has scattering properties. A simple approach is introduced to utilize scattered radiation to obtain 'pure absorption' and 'pure refraction' images

  7. PhosphoSiteAnalyzer

    DEFF Research Database (Denmark)

    Bennetzen, Martin V; Cox, Jürgen; Mann, Matthias; Andersen, Jens S.

    2012-01-01

    Phosphoproteomic experiments are routinely conducted in laboratories worldwide, and because of the fast development of mass spectrometric techniques and efficient phosphopeptide enrichment methods, researchers frequently end up having lists with tens of thousands of phosphorylation sites for...... sets that have been subjected to kinase prediction using the previously published NetworKIN algorithm. NetworKIN applies sophisticated linear motif analysis and contextual network modeling to obtain kinase-substrate associations with high accuracy and sensitivity. PhosphoSiteAnalyzer provides an...

  8. Lear CAN analyzer

    OpenAIRE

    Peiró Ibañez, Felipe

    2013-01-01

    Since it was introduced in the automotive industry, the protocol CAN (Controller Area Network) has been widely used for its benefits. This has led many companies to offer several hardware and software solutions in order to monitor the communications that gives this protocol. The current master thesis presents the Lear CAN Analyzer as a software tool developed within the company LEAR Corporation. It is designed to be used in the automobile industry as a complement or substitute for other co...

  9. Analyzing business process management

    OpenAIRE

    Skjæveland, Børge

    2013-01-01

    Within the Oil & Gas Industry, the market is constantly growing more competitive, forcing companies to continually adapt to changes. Companies need to cut costs and improve the business efficiency. One way of successfully managing these challenges is to implement business process management in the organization. This thesis will analyze how Oceaneering Asset Integrity AS handled the implementation of a Business Process Management System and the effects it had on the employees. The main goal...

  10. Magnetoresistive Emulsion Analyzer

    OpenAIRE

    Lin, Gungun; Baraban, Larysa; Han, Luyang; Karnaushenko, Daniil; Makarov, Denys; Cuniberti, Gianaurelio; Schmidt, Oliver G.

    2013-01-01

    We realize a magnetoresistive emulsion analyzer capable of detection, multiparametric analysis and sorting of ferrofluid-containing nanoliter-droplets. The operation of the device in a cytometric mode provides high throughput and quantitative information about the dimensions and magnetic content of the emulsion. Our method offers important complementarity to conventional optical approaches involving ferrofluids, and paves the way to the development of novel compact tools for diagnostics and n...

  11. Radioisotope analyzer of barium

    International Nuclear Information System (INIS)

    Principle of operation and construction of radioisotope barium sulphate analyzer type MZB-2 for fast determination of barium sulphate content in barite ores and enrichment products are described. The gauge equipped with Am-241 and a scintillation detector enables measurement of barium sulphate content in prepared samples of barite ores in the range 60% - 100% with the accuracy of 1%. The gauge is used in laboratories of barite mine and ore processing plant. 2 refs., 2 figs., 1 tab. (author)

  12. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  13. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  14. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. IPv6 Protocol Analyzer

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the emerging of next generation Intemet protocol (IPv6), it is expected to replace the current version of Internet protocol (IPv4) that will be exhausted in the near future. Besides providing adequate address space, some other new features are included into the new 128 bits of IP such as IP auto configuration, quality of service, simple routing capability, security, mobility and multicasting. The current protocol analyzer will not be able to handle IPv6 packets. This paper will focus on developing protocol analyzer that decodes IPv6 packet. IPv6 protocol analyzer is an application module,which is able to decode the IPv6 packet and provide detail breakdown of the construction of the packet. It has to understand the detail construction of the IPv6, and provide a high level abstraction of bits and bytes of the IPv6 packet.Thus it increases network administrators' understanding of a network protocol,helps he/she in solving protocol related problem in a IPv6 network environment.

  16. Effect of texturing process involving saw-damage etching on crystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunho; Park, Sungeun; Kang, Byungjun; Kim, Seongtak; Tark, Sung Ju; Kim, Donghwan, E-mail: solar@korea.ac.kr; Dahiwale, S.S.

    2013-11-01

    For high efficiency silicon solar cells, surface texturing is used to increase the short circuit current by reducing the surface reflection loss. Surface texturing is an anisotropic wet chemical etching process commonly used to form random pyramids. We investigated how the process is affected by surface conditions. We also compared the texturing behavior and cell performances of as-cut, polished and saw-damage etched wafers. Textured samples with different processing times were analyzed to detect pyramids and determine weighted reflectances. After the texturing process, conventional screen-printed solar cells were fabricated to observe the cell performance. The pseudo I–V curves and quantum efficiency for the samples were analyzed. Performance of samples with different surface conditions makes no difference. Thus, the processing-cost of solar cells can be reduced by omitting the saw-damage etching process.

  17. Solar Sail Propulsion for Interplanetary Cubesats

    Science.gov (United States)

    Johnson, Les; Sobey, Alex; Sykes, Kevin

    2015-01-01

    NASA is developing two small satellite missions as part of the Advanced Exploration Systems (AES) Program, both of which will use a solar sail to enable their scientific objectives. Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. This continuous photon pressure provides propellantless thrust, allowing for very high (Delta)V maneuvers on long-duration, deep space exploration. Since reflected light produces thrust, solar sails require no onboard propellant. Solar sail technology is rapidly maturing for space propulsion applications within NASA and around the world.

  18. Solar thermal aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Charles L. (Livermore, CA)

    2007-09-18

    A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  19. Holographic Solar Photon Thrusters

    Science.gov (United States)

    Johnson, Les; Matloff, Greg

    2006-01-01

    A document discusses a proposal to incorporate holographic optical elements into solar photon thrusters (SPTs). First suggested in 1990, SPTs would be systems of multiple reflective, emissive, and absorptive surfaces (solar sails) that would be attached to spacecraft orbiting the Earth to derive small propulsive forces from radiation pressures. An SPT according to the proposal would include, among other things, a main sail. One side of the sail would be highly emissive and would normally face away from the Earth. The other side would be reflective and would be covered by white-light holographic images that would alternately become reflective, transmissive, and absorptive with small changes in the viewing angle. When the spacecraft was at a favorable orbital position, the main sail would be oriented to reflect sunlight in a direction to maximize the solar thrust; when not in a favorable position, the main sail would be oriented to present a substantially absorptive/emissive aspect to minimize the solar drag. By turning the main sail slightly to alternate between the reflective and absorptive/ emissive extremes, one could achieve nearly a doubling or halving of the radiational momentum transfer and, hence, of the solar thrust.

  20. Fluorescence analyzer for lignin

    Science.gov (United States)

    Berthold, John W.; Malito, Michael L.; Jeffers, Larry

    1993-01-01

    A method and apparatus for measuring lignin concentration in a sample of wood pulp or black liquor comprises a light emitting arrangement for emitting an excitation light through optical fiber bundles into a probe which has an undiluted sensing end facing the sample. The excitation light causes the lignin concentration to produce fluorescent emission light which is then conveyed through the probe to analyzing equipment which measures the intensity of the emission light. Measures a This invention was made with Government support under Contract Number DOE: DE-FC05-90CE40905 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.

  1. Analyzing Chinese Financial Reporting

    Institute of Scientific and Technical Information of China (English)

    SABRINA; ZHANG

    2008-01-01

    If the world’s capital markets could use a harmonized accounting framework it would not be necessary for a comparison between two or more sets of accounting standards. However,there is much to do before this becomes reality.This article aims to pres- ent a general overview of China’s General Accepted Accounting Principles(GAAP), U.S.General Accepted Accounting Principles and International Financial Reporting Standards(IFRS),and to analyze the differ- ences among IFRS,U.S.GAAP and China GAAP using fixed assets as an example.

  2. Field Deployable DNA analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, E; Christian, A; Marion, J; Sorensen, K; Arroyo, E; Vrankovich, G; Hara, C; Nguyen, C

    2005-02-09

    This report details the feasibility of a field deployable DNA analyzer. Steps for swabbing cells from surfaces and extracting DNA in an automatable way are presented. Since enzymatic amplification reactions are highly sensitive to environmental contamination, sample preparation is a crucial step to make an autonomous deployable instrument. We perform sample clean up and concentration in a flow through packed bed. For small initial samples, whole genome amplification is performed in the packed bed resulting in enough product for subsequent PCR amplification. In addition to DNA, which can be used to identify a subject, protein is also left behind, the analysis of which can be used to determine exposure to certain substances, such as radionuclides. Our preparative step for DNA analysis left behind the protein complement as a waste stream; we determined to learn if the proteins themselves could be analyzed in a fieldable device. We successfully developed a two-step lateral flow assay for protein analysis and demonstrate a proof of principle assay.

  3. Ring Image Analyzer

    Science.gov (United States)

    Strekalov, Dmitry V.

    2012-01-01

    Ring Image Analyzer software analyzes images to recognize elliptical patterns. It determines the ellipse parameters (axes ratio, centroid coordinate, tilt angle). The program attempts to recognize elliptical fringes (e.g., Newton Rings) on a photograph and determine their centroid position, the short-to-long-axis ratio, and the angle of rotation of the long axis relative to the horizontal direction on the photograph. These capabilities are important in interferometric imaging and control of surfaces. In particular, this program has been developed and applied for determining the rim shape of precision-machined optical whispering gallery mode resonators. The program relies on a unique image recognition algorithm aimed at recognizing elliptical shapes, but can be easily adapted to other geometric shapes. It is robust against non-elliptical details of the image and against noise. Interferometric analysis of precision-machined surfaces remains an important technological instrument in hardware development and quality analysis. This software automates and increases the accuracy of this technique. The software has been developed for the needs of an R&TD-funded project and has become an important asset for the future research proposal to NASA as well as other agencies.

  4. Solution for Improve the Efficiency of Solar Photovoltaic Installation

    OpenAIRE

    Petru Chioncel; Cristian Paul Chioncel; Nicoleta Gillich

    2013-01-01

    This paper present a solution for improving efficiency of solar photovoltaic installation, realized with fixed solar photovoltaic modules, placed in solar parks or individual installations. The proposed solution to increase the radiation on the solar photovoltaic panels is to use some thin plates covered with a reflective blanket, mounted in front of the solar photovoltaic modules, with the possibility of their adjustment.

  5. Mars Solar Power

    Science.gov (United States)

    Landis, Geoffrey A.; Kerslake, Thomas W.; Jenkins, Phillip P.; Scheiman, David A.

    2004-01-01

    NASA missions to Mars, both robotic and human, rely on solar arrays for the primary power system. Mars presents a number of challenges for solar power system operation, including a dusty atmosphere which modifies the spectrum and intensity of the incident solar illumination as a function of time of day, degradation of the array performance by dust deposition, and low temperature operation. The environmental challenges to Mars solar array operation will be discussed and test results of solar cell technology operating under Mars conditions will be presented, along with modeling of solar cell performance under Mars conditions. The design implications for advanced solar arrays for future Mars missions is discussed, and an example case, a Martian polar rover, are analyzed.

  6. Analyzing Pseudophosphatase Function.

    Science.gov (United States)

    Hinton, Shantá D

    2016-01-01

    Pseudophosphatases regulate signal transduction cascades, but their mechanisms of action remain enigmatic. Reflecting this mystery, the prototypical pseudophosphatase STYX (phospho-serine-threonine/tyrosine-binding protein) was named with allusion to the river of the dead in Greek mythology to emphasize that these molecules are "dead" phosphatases. Although proteins with STYX domains do not catalyze dephosphorylation, this in no way precludes their having other functions as integral elements of signaling networks. Thus, understanding their roles in signaling pathways may mark them as potential novel drug targets. This chapter outlines common strategies used to characterize the functions of pseudophosphatases, using as an example MK-STYX [mitogen-activated protein kinase (MAPK) phospho-serine-threonine/tyrosine binding], which has been linked to tumorigenesis, apoptosis, and neuronal differentiation. We start with the importance of "restoring" (when possible) phosphatase activity in a pseudophosphatase so that the active mutant may be used as a comparison control throughout immunoprecipitation and mass spectrometry analyses. To this end, we provide protocols for site-directed mutagenesis, mammalian cell transfection, co-immunoprecipitation, phosphatase activity assays, and immunoblotting that we have used to investigate MK-STYX and the active mutant MK-STYXactive. We also highlight the importance of utilizing RNA interference (RNAi) "knockdown" technology to determine a cellular phenotype in various cell lines. Therefore, we outline our protocols for introducing short hairpin RNA (shRNA) expression plasmids into mammalians cells and quantifying knockdown of gene expression with real-time quantitative PCR (qPCR). A combination of cellular, molecular, biochemical, and proteomic techniques has served as powerful tools in identifying novel functions of the pseudophosphatase MK-STYX. Likewise, the information provided here should be a helpful guide to elucidating the

  7. A Reflective Look at Reflecting Teams

    Science.gov (United States)

    Pender, Rebecca L.; Stinchfield, Tracy

    2012-01-01

    This article reviewed existing literature and research on the reflecting team process. There is a dearth of empirical research that explores the reflecting team process and the outcome of counseling that uses reflecting teams. Implications of using reflecting teams for counselors, counselor educators, and clients will be discussed. A call for…

  8. Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

    Science.gov (United States)

    Wilcox, Brian H.

    2012-01-01

    Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by

  9. Residual gas analyzer calibration

    Science.gov (United States)

    Lilienkamp, R. H.

    1972-01-01

    A technique which employs known gas mixtures to calibrate the residual gas analyzer (RGA) is described. The mass spectra from the RGA are recorded for each gas mixture. This mass spectra data and the mixture composition data each form a matrix. From the two matrices the calibration matrix may be computed. The matrix mathematics requires the number of calibration gas mixtures be equal to or greater than the number of gases included in the calibration. This technique was evaluated using a mathematical model of an RGA to generate the mass spectra. This model included shot noise errors in the mass spectra. Errors in the gas concentrations were also included in the valuation. The effects of these errors was studied by varying their magnitudes and comparing the resulting calibrations. Several methods of evaluating an actual calibration are presented. The effects of the number of gases in then, the composition of the calibration mixture, and the number of mixtures used are discussed.

  10. Analyzing Cosmic Bubble Collisions

    CERN Document Server

    Gobbetti, Roberto

    2012-01-01

    We develop a set of controlled, analytic approximations to study the effects of bubble collisions on cosmology. We expand the initial perturbation to the inflaton field caused by the collision in a general power series, and determine its time evolution during inflation in terms of the coefficients in the expansion. In models where the observer's bubble undergoes sufficient slow-roll inflation to solve the flatness problem, in the thin wall limit only one coefficient in the expansion is relevant to observational cosmology, allowing nearly model-independent predictions. We discuss two approaches to determining the initial perturbation to the inflaton and the implications for the sign of the effect (a hot or cold spot on the Cosmic Microwave Background temperature map). Lastly, we analyze the effects of collisions with thick-wall bubbles, i.e. away from the thin-wall limit.

  11. Analyzing business models

    DEFF Research Database (Denmark)

    Nielsen, Christian

    2014-01-01

    New types of disclosure and reporting are argued to be vital in order to convey a transparent picture of the true state of the company. However, they are unfortunately not without problems as these types of information are somewhat more complex than the information provided in the traditional......, because the costs of processing and analyzing it exceed the benefits indicating bounded rationality. Hutton (2002) concludes that the analyst community’s inability to raise important questions on quality of management and the viability of its business model inevitably led to the Enron debacle. There seems...... to be evidence of the fact that all types of corporate stakeholders from management to employees, owners, the media and politicians have grave difficulties in interpreting new forms of reporting. One hypothesis could be that if managements’ own understanding of value creation is disclosed to the...

  12. Analyzing architecture articles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present study, we express the quality, function, and characteristics of architecture to help people comprehensively understand what architecture is. We also reveal the problems and conflict found in population, land, water resources, pollution, energy, and the organization systems in construction. China’s economy is transforming. We should focus on the cities, architectural environment, energy conservation, emission-reduction, and low-carbon output that will result in successful green development. We should macroscopically and microscopically analyze the development, from the natural environment to the artificial environment; from the relationship between human beings and nature to the combination of social ecology in cities, and farmlands. We must learn to develop and control them harmoniously and scientifically to provide a foundation for the methods used in architecture research.

  13. PDA: Pooled DNA analyzer

    Directory of Open Access Journals (Sweden)

    Lin Chin-Yu

    2006-04-01

    Full Text Available Abstract Background Association mapping using abundant single nucleotide polymorphisms is a powerful tool for identifying disease susceptibility genes for complex traits and exploring possible genetic diversity. Genotyping large numbers of SNPs individually is performed routinely but is cost prohibitive for large-scale genetic studies. DNA pooling is a reliable and cost-saving alternative genotyping method. However, no software has been developed for complete pooled-DNA analyses, including data standardization, allele frequency estimation, and single/multipoint DNA pooling association tests. This motivated the development of the software, 'PDA' (Pooled DNA Analyzer, to analyze pooled DNA data. Results We develop the software, PDA, for the analysis of pooled-DNA data. PDA is originally implemented with the MATLAB® language, but it can also be executed on a Windows system without installing the MATLAB®. PDA provides estimates of the coefficient of preferential amplification and allele frequency. PDA considers an extended single-point association test, which can compare allele frequencies between two DNA pools constructed under different experimental conditions. Moreover, PDA also provides novel chromosome-wide multipoint association tests based on p-value combinations and a sliding-window concept. This new multipoint testing procedure overcomes a computational bottleneck of conventional haplotype-oriented multipoint methods in DNA pooling analyses and can handle data sets having a large pool size and/or large numbers of polymorphic markers. All of the PDA functions are illustrated in the four bona fide examples. Conclusion PDA is simple to operate and does not require that users have a strong statistical background. The software is available at http://www.ibms.sinica.edu.tw/%7Ecsjfann/first%20flow/pda.htm.

  14. Space Solar Cell Characterization Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Measures, characterizes, and analyzes photovoltaic materials and devices. The primary focus is the measurement and characterization of solar cell response...

  15. The thermodynamic solar energy

    International Nuclear Information System (INIS)

    The thermodynamic solar energy is the technic in the whole aiming to transform the solar radiation energy in high temperature heat and then in mechanical energy by a thermodynamic cycle. These technic are most often at an experimental scale. This paper describes and analyzes the research programs developed in the advanced countries, since 1980. (A.L.B.)

  16. Pseudostupidity and analyzability.

    Science.gov (United States)

    Cohn, L S

    1989-01-01

    This paper seeks to heighten awareness of pseudostupidity and the potential analyzability of patients who manifest it by defining and explicating it, reviewing the literature, and presenting in detail the psychoanalytic treatment of a pseudostupid patient. Pseudostupidity is caused by an inhibition of the integration and synthesis of thoughts resulting in a discrepancy between intellectual capacity and apparent intellect. The patient's pseudostupidity was determined in part by his need to prevent his being more successful than father, i.e., defeating his oedipal rival. Knowing and learning were instinctualized. The patient libidinally and defensively identified with father's passive, masochistic position. He needed to frustrate the analyst as he had felt excited and frustrated by his parents' nudity and thwarted by his inhibitions. He wanted to cause the analyst to feel as helpless as he, the patient, felt. Countertransference frustration was relevant and clinically useful in the analysis. Interpretation of evolving relevant issues led to more anxiety and guilt, less pseudostupidity, a heightened alliance, and eventual working through. Negative therapeutic reactions followed the resolution of pseudostupidity. PMID:2708771

  17. Downhole Fluid Analyzer Development

    Energy Technology Data Exchange (ETDEWEB)

    Bill Turner

    2006-11-28

    A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.

  18. Chandrayaan-1 observations of backscattered solar wind protons from the lunar regolith: Dependence on the solar wind speed

    Science.gov (United States)

    Lue, Charles; Futaana, Yoshifumi; Barabash, Stas; Wieser, Martin; Bhardwaj, Anil; Wurz, Peter

    2014-05-01

    We study the backscattering of solar wind protons from the lunar regolith using the Solar Wind Monitor of the Sub-keV Atom Reflecting Analyzer on Chandrayaan-1. Our study focuses on the component of the backscattered particles that leaves the regolith with a positive charge. We find that the fraction of the incident solar wind protons that backscatter as protons, i.e., the proton-backscattering efficiency, has an exponential dependence on the solar wind speed that varies from ~0.01% to ~1% for solar wind speeds of 250 km/s to 550 km/s. We also study the speed distribution of the backscattered protons in the fast (~550 km/s) solar wind case and find both a peak speed at ~80% of the solar wind speed and a spread of ~85 km/s. The observed flux variations and speed distribution of the backscattered protons can be explained by a speed-dependent charge state of the backscattered particles.

  19. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  20. Digital Microfluidics Sample Analyzer

    Science.gov (United States)

    Pollack, Michael G.; Srinivasan, Vijay; Eckhardt, Allen; Paik, Philip Y.; Sudarsan, Arjun; Shenderov, Alex; Hua, Zhishan; Pamula, Vamsee K.

    2010-01-01

    Three innovations address the needs of the medical world with regard to microfluidic manipulation and testing of physiological samples in ways that can benefit point-of-care needs for patients such as premature infants, for which drawing of blood for continuous tests can be life-threatening in their own right, and for expedited results. A chip with sample injection elements, reservoirs (and waste), droplet formation structures, fluidic pathways, mixing areas, and optical detection sites, was fabricated to test the various components of the microfluidic platform, both individually and in integrated fashion. The droplet control system permits a user to control droplet microactuator system functions, such as droplet operations and detector operations. Also, the programming system allows a user to develop software routines for controlling droplet microactuator system functions, such as droplet operations and detector operations. A chip is incorporated into the system with a controller, a detector, input and output devices, and software. A novel filler fluid formulation is used for the transport of droplets with high protein concentrations. Novel assemblies for detection of photons from an on-chip droplet are present, as well as novel systems for conducting various assays, such as immunoassays and PCR (polymerase chain reaction). The lab-on-a-chip (a.k.a., lab-on-a-printed-circuit board) processes physiological samples and comprises a system for automated, multi-analyte measurements using sub-microliter samples of human serum. The invention also relates to a diagnostic chip and system including the chip that performs many of the routine operations of a central labbased chemistry analyzer, integrating, for example, colorimetric assays (e.g., for proteins), chemiluminescence/fluorescence assays (e.g., for enzymes, electrolytes, and gases), and/or conductometric assays (e.g., for hematocrit on plasma and whole blood) on a single chip platform.

  1. Soft Decision Analyzer

    Science.gov (United States)

    Steele, Glen; Lansdowne, Chatwin; Zucha, Joan; Schlensinger, Adam

    2013-01-01

    The Soft Decision Analyzer (SDA) is an instrument that combines hardware, firmware, and software to perform realtime closed-loop end-to-end statistical analysis of single- or dual- channel serial digital RF communications systems operating in very low signal-to-noise conditions. As an innovation, the unique SDA capabilities allow it to perform analysis of situations where the receiving communication system slips bits due to low signal-to-noise conditions or experiences constellation rotations resulting in channel polarity in versions or channel assignment swaps. SDA s closed-loop detection allows it to instrument a live system and correlate observations with frame, codeword, and packet losses, as well as Quality of Service (QoS) and Quality of Experience (QoE) events. The SDA s abilities are not confined to performing analysis in low signal-to-noise conditions. Its analysis provides in-depth insight of a communication system s receiver performance in a variety of operating conditions. The SDA incorporates two techniques for identifying slips. The first is an examination of content of the received data stream s relation to the transmitted data content and the second is a direct examination of the receiver s recovered clock signals relative to a reference. Both techniques provide benefits in different ways and allow the communication engineer evaluating test results increased confidence and understanding of receiver performance. Direct examination of data contents is performed by two different data techniques, power correlation or a modified Massey correlation, and can be applied to soft decision data widths 1 to 12 bits wide over a correlation depth ranging from 16 to 512 samples. The SDA detects receiver bit slips within a 4 bits window and can handle systems with up to four quadrants (QPSK, SQPSK, and BPSK systems). The SDA continuously monitors correlation results to characterize slips and quadrant change and is capable of performing analysis even when the

  2. Development of electro-optic systems for self cleaning concentrated solar reflectors

    Science.gov (United States)

    Stark, Jeremy W.

    The current demand for energy usage in the world is increasing at a rapid pace; in China alone, the electricity usage has increased by 12% per year from 2006-2010, where more than 75% of electrical power is produced by coal burning facilities. Numerous studies have shown the effects of carbon dioxide emissions on global climate change, and even showing the permanence of high carbon dioxide levels after emissions cease. Current trends away from carbon emitting power facilities are pushing solar energy into a position for many new solar power plants to be constructed. Terrestrial solar energy at AM1.5 is generally given at 1kW/m2, which is a vast free source of energy that can be be harvested to meet the global demand for electricity. Aside from some areas receiving intermittent levels of solar insolation, one of the largest hindrances to large scale solar power production is obscuration of sunlight on solar collectors caused by dust deposition. In areas with the highest average solar insolation, dust deposition is a major problem for maintaining a constant maximum power output. The southern Negev desert in Israel receives on average 17g/m2 per month in dust deposition on solar installations, which in turn causes losses of a third of the total power output of the installation. In these areas, water is a scarce commodity, which can only be used to clean solar installations at a prohibitive cost. To resolve this problem, a cost effective solution would be the application of electrodynamic screens (EDS), which can be implemented by embedding a set of parallel electrodes into the sun facing surface of solar collectors, including concentrating mirrors or photovoltaic (PV) modules, and applying a low frequency pulsed voltage to these electrodes. Three major contributions made in the course of this research in advancing (EDS) for self-cleaning solar mirrors are: (1) development of non-contact specular reflectometer for solar mirrors that allows measurement of reflectance

  3. Reflectance spectra of subarctic lichens

    International Nuclear Information System (INIS)

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the mid latitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 μm, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future. (author)

  4. Photovoltaic module with light reflecting backskin

    Science.gov (United States)

    Gonsiorawski, Ronald C.

    2007-07-03

    A photovoltaic module comprises electrically interconnected and mutually spaced photovoltaic cells that are encapsulated by a light-transmitting encapsulant between a light-transparent front cover and a back cover, with the back cover sheet being an ionomer/nylon alloy embossed with V-shaped grooves running in at least two directions and coated with a light reflecting medium so as to provide light-reflecting facets that are aligned with the spaces between adjacent cells and oriented so as to reflect light falling in those spaces back toward said transparent front cover for further internal reflection onto the solar cells, whereby substantially all of the reflected light will be internally reflected from said cover sheet back to the photovoltaic cells, thereby increasing the current output of the module. The internal reflector improves power output by as much as 67%.

  5. CVD molybdenum films of high infrared reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Carver, G. E.

    1979-01-01

    Molybdenum thin films of high infrared reflectance have been deposited by pyrolytic decomposition of molybdenum carbonyl (Mo(CO)/sub 6/), and by hydrogen reduction of molybdenum pentachloride (MoCl/sub 5/). Reflectance values within 0.7% of the reflectance of supersmooth bulk molybdenum have been attained by annealing films of lower reflectance in both reducing and non-reducing atmospheres. All depositions and anneals proceed at atmospheric pressure, facilitating a continuous, flow-through fabrication. These reflectors combine the high temperature stability of molybdenum thin films with the infrared reflectance of a material such as aluminum. Deposition from Mo(CO)/sub 6/ under oxidizing conditions, and subsequent anneal in a reducing atmosphere, results in films that combine high solar absorptance with low thermal emittance. If anti-reflected, black molybdenum films can serve as highly selective single layer photothermal converters. Structural, compositional, and crystallographic properties have been measured after both deposition and anneal.

  6. Achievement report for fiscal 1997 on developing a silicon manufacturing process with reduced energy consumption. Investigation and research on analyzing practical application of a technology to manufacture solar cell silicon raw materials; 1997 nendo energy shiyo gorika silicon seizo process kaihatsu. Taiyo denchi silicon genryo seizo gijutsu no jitsuyoka kaiseki ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This paper describes the achievement in fiscal 1997 of analyzing practical application of a technology to manufacture solar cell silicon raw materials. Silicon consumption for solar cells in fiscal 1997 has increased to 2000-ton level, and the supply has been very tight. For drastic improvement in the demand and supply situation, development of SOG-Si manufacturing technology and its early practical application are desired. The development of the NEDO mass-production technology using melting and refining has completed constructing the process facilities in fiscal 1998, and will enter the stage of operational research. However, insufficiency in the basic data about behavior of impurities is inhibiting the development. In the substrate manufacturing technology, discussions have shown progress on use of diversifying silicons outside the standard by using the electromagnetic casting process. For slicing and processing the substrates, development of a high-performance slicing equipment and automatic rough rinsing machine is under way. Properties required on silicon raw materials vary considerably widely because of difference in cell making systems and conditions, which is attributable to unknown impurity behavior. When 1GW production is assumed, the cell module manufacturing cost is calculated as 137 yen/W, for which low-cost mass production for its realization, slicing productivity enhancement, and cost reduction are required. The paper also describes site surveys in overseas countries. (NEDO)

  7. A semi-analytical model for semiconductor solar cells

    Science.gov (United States)

    Ding, D.; Johnson, S. R.; Yu, S.-Q.; Wu, S.-N.; Zhang, Y.-H.

    2011-12-01

    A semi-analytical model is constructed for single- and multi-junction solar cells. This model incorporates the key performance aspects of practical devices, including nonradiative recombination, photon recycling within a given junction, spontaneous emission coupling between junctions, and non-step-like absorptance and emittance with below-bandgap tail absorption. Four typical planar structures with the combinations of a smooth/textured top surface and an absorbing/reflecting substrate (or backside surface) are investigated, through which the extracted power and four types of fundamental loss mechanisms, transmission, thermalization, spatial-relaxation, and recombination loss are analyzed for both single- and multi-junction solar cells. The below-bandgap tail absorption increases the short-circuit current but decreases the output and open-circuit voltage. Using a straightforward formulism this model provides the initial design parameters and the achievable efficiencies for both single- and multiple-junction solar cells over a wide range of material quality. The achievable efficiency limits calculated using the best reported materials and AM1.5 G one sun for GaAs and Si single-junction solar cells are, respectively, 27.4 and 21.1% for semiconductor slabs with a flat surface and a non-reflecting index-matched absorbing substrate, and 30.8 and 26.4% for semiconductor slabs with a textured surface and an ideal 100% reflecting backside surface. Two important design rules for both single- and multi-junction solar cells are established: i) the optimal junction thickness decreases and the optimal bandgap energy increases when nonradiative recombination increases; and ii) the optimal junction thickness increases and the optimal bandgap energy decreases for higher solar concentrations.

  8. Solar flares

    International Nuclear Information System (INIS)

    In this thesis an electrodynamic model for solar flares is developed. The main theoretical achievements underlying the present study are treated briefly and the observable flare parameters are described within the framework of the flare model of this thesis. The flare model predicts large induced electric fields. Therefore, acceleration processes of charged particles by direct electric fields are treated. The spectrum of the accelerated particles in strong electric fields is calculated, 3 with the electric field and the magnetic field perpendicular and in the vicinity of an X-type magnetic neutral line. An electromagnetic field configuration arises in the case of a solar flare. A rising current filament in a quiescent background bipolar magnetic field causes naturally an X-type magnetic field configuration below the filament with a strong induced electric field perpendicular to the ambient magnetic field. This field configuration drives particles and magnetic energy towards the neutral line, where a current sheet is generated. The global evolution of the fields in the flare is determined by force balance of the Lorentz forces on the filament and the force balance on the current sheet. The X-ray, optical and radio observations of a large solar flare on May 16, 1981 are analyzed. It is found that these data fit the model very well. (Auth.)

  9. Analyze of meteorological data for development of solar collectors

    International Nuclear Information System (INIS)

    The objective of the research was to investigate the increase in heat yield, if the collector is tracking the sun, and to base the purposefulness of providing the collector device with additional equipment for keeping the surface of the collector perpendicular to the sun beams all the day round

  10. Orientations to Reflective Practice.

    Science.gov (United States)

    Wellington, Bud; Austin, Patricia

    1996-01-01

    Delineates five orientations to reflective practice: immediate, technical, deliberative, dialectic, and transpersonal, each reflecting different social science bases and beliefs and values about education. Views them as interactive, interdependent, noncompeting, aspects of reflective practice. (SK)

  11. Photovoltaic solar energy conversion

    CERN Document Server

    Bauer, Gottfried H

    2015-01-01

    This concise primer on photovoltaic solar energy conversion invites readers to reflect on the conversion of solar light into energy at the most fundamental level and encourages newcomers to the field to help find meaningful answers on how photovoltaic solar energy conversion can work (better), eventually contributing to its ongoing advancement. The book is based on lectures given to graduate students in the Physics Department at the University of Oldenburg over the last two decades, yet also provides an easy-to-follow introduction for doctoral and postdoctoral students from related disciplines such as the materials sciences and electrical engineering. Inspired by classic textbooks in the field, it reflects the author’s own ideas on how to understand, visualize and eventually teach the microscopic physical mechanisms and effects, while keeping the text as concise as possible so as to introduce interested readers to the field and balancing essential knowledge with open questions.

  12. Method to analyze remotely sensed spectral data

    Science.gov (United States)

    Stork, Christopher L.; Van Benthem, Mark H.

    2009-02-17

    A fast and rigorous multivariate curve resolution (MCR) algorithm is applied to remotely sensed spectral data. The algorithm is applicable in the solar-reflective spectral region, comprising the visible to the shortwave infrared (ranging from approximately 0.4 to 2.5 .mu.m), midwave infrared, and thermal emission spectral region, comprising the thermal infrared (ranging from approximately 8 to 15 .mu.m). For example, employing minimal a priori knowledge, notably non-negativity constraints on the extracted endmember profiles and a constant abundance constraint for the atmospheric upwelling component, MCR can be used to successfully compensate thermal infrared hyperspectral images for atmospheric upwelling and, thereby, transmittance effects. Further, MCR can accurately estimate the relative spectral absorption coefficients and thermal contrast distribution of a gas plume component near the minimum detectable quantity.

  13. Solar air-conditioning. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Within the 3rd International Conference on solar air-conditioning in Palermo (Italy) at 30th September to 2nd October, 2009 the following lectures were held: (1) Removal of non-technological barriers to solar cooling technology across Southern European islands (Stefano Rugginenti); (2) The added economic and environmental value of solar thermal systems in microgrids with combined heat and power (Chris Marney); (3) Australian solar cooling interest group (Paul Kohlenbach); (4) Designing of a technology roadmap for solar assisted air conditioning in Austria (Hilbert Focke); (5) Solar cooling in the new context of renewable policies at European level (Raffaele Piria); (6) Prototype of a solar driven steam jet ejector chiller (Clemens Pollerberg); (7) New integrated solar air conditioning system (Joan Carlos Bruno); (8) Primary energy optimised operation of solar driven desiccant evaporative cooling systems through innovative control strategies; (9) Green chiller association (Uli Jakob); (10) Climate Well {sup registered} (Olof Hallstrom); (11) Low capacity absorption chillers for solar cooling applications (Gregor Weidner); (12) Solar cooling in residential, small scale commercial and industrial applications with adsorption technology (Walter Mittelbach); (13) French solar heating and cooling development programme based on energy performance (Daniel Mugnier); (14) Mirrox fresnel process heat collectors for industrial applications and solar cooling (Christian Zahler); (15) Modelling and analyzing solar cooling systems in polysun (Seyen Hossein Rezaei); (16) Solar cooling application in Valle Susa Italy (Sufia Jung); (17) Virtual case study on small solar cooling systems within the SolarCombi+Project (Bjoern Nienborg); (18) Design of solar cooling plants under uncertainty (Fernando Dominguez-Munoz); (19) Fast pre-design of systems using solar thermally driven chillers (Hans-Martin Henning); (20) Design of a high fraction solar heating and cooling plant in southern

  14. Solar Features - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A solar flare is a short-lived sudden increase in the intensity of radiation emitted in the neighborhood of sunspots. For many years it was best monitored in the...

  15. Reflectivity, reflexivity and situated reflective practice

    OpenAIRE

    Malthouse, R; Roffey-Barentsen, J; Watts, DM

    2014-01-01

    This paper describes an aspect of reflective practice referred to as ‘Situated Reflective Practice’ (SRP). The overarching theory is derived from social theories of structuration and reflexivity. In particular, from Giddens’s (1984) theory of structuration, this sees social life as interplay of agency and structure. Discussion of the research reported here centres on the nature of such situated reflection, considers related literature and presents the data collected in a recent small-scale st...

  16. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  17. Modes of collaborative reflection

    OpenAIRE

    Degeling, Martin; Prilla, Michael

    2011-01-01

    In this paper, we describe different modes of collaborative reflection as processes of learning at the workplace. We explain why reflection is a decisive means of learning and - based on the modes we describe - how groups of people can be supported in reflection together. For this, we describe how scheduled, concurrent and spontaneous collaborative reflection can be supported by articulation, guidance and synergizing.

  18. Constraining Solar Wind Heating Processes by Kinetic Properties of Heavy Ions

    Science.gov (United States)

    Tracy, Patrick J.; Kasper, Justin C.; Raines, Jim M.; Shearer, Paul; Gilbert, Jason A.; Zurbuchen, Thomas H.

    2016-06-01

    We analyze the heavy ion components (A >4 amu ) in collisionally young solar wind plasma and show that there is a clear, stable dependence of temperature on mass, probably reflecting the conditions in the solar corona. We consider both linear and power law forms for the dependence and find that a simple linear fit of the form Ti/Tp=(1.35 ±.02 )mi/mp describes the observations twice as well as the equivalent best fit power law of the form Ti/Tp=(mi/mp) 1.07 ±.01 . Most importantly we find that current model predictions based on turbulent transport and kinetic dissipation are in agreement with observed nonthermal heating in intermediate collisional age plasma for m /q heating in multispecies plasmas, along with predictions to be tested by the upcoming Solar Probe Plus and Solar Orbiter missions to the near-Sun environment.

  19. Guide on reflectivity data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Soo; Ku, Ja Seung; Seong, Baek Seok; Lee, Chang Hee; Hong, Kwang Pyo; Choi, Byung Hoon

    2004-09-01

    This report contains reduction and fitting process of neutron reflectivity data by REFLRED and REFLFIT in NIST. Because the detail of data reduction like BKG, footprint and data normalization was described, it will be useful to the user who has no experience in this field. Also, reflectivity and BKG of d-PS thin film were measured by HANARO neutron reflectometer. From these, the structure of d-PS thin film was analyzed with REFLRED and REFLFIT. Because the structure of thin film such as thickness, roughness and SLD was attained in the work, the possibility of data analysis with REFLRED and REFLFIT was certified.

  20. Guide on reflectivity data analysis

    International Nuclear Information System (INIS)

    This report contains reduction and fitting process of neutron reflectivity data by REFLRED and REFLFIT in NIST. Because the detail of data reduction like BKG, footprint and data normalization was described, it will be useful to the user who has no experience in this field. Also, reflectivity and BKG of d-PS thin film were measured by HANARO neutron reflectometer. From these, the structure of d-PS thin film was analyzed with REFLRED and REFLFIT. Because the structure of thin film such as thickness, roughness and SLD was attained in the work, the possibility of data analysis with REFLRED and REFLFIT was certified

  1. FTIR reflectance spectra of zirconium titanate based dielectric ceramics

    International Nuclear Information System (INIS)

    A series of tin doped zirconium titanate compositions has been analyzed for dielectric characteristics using Far IR reflectance data. The trends in quality factor data were found to be as expected. In these experiments, infrared reflectivity measurements have been obtained on ZrxTiySnzO4 (x + y + z = 2) compositions. The reflection spectra of the system are analyzed

  2. Reflectivity, Reflexivity and Situated Reflective Practice

    Science.gov (United States)

    Malthouse, Richard; Roffey-Barentsen, Jodi; Watts, Mike

    2014-01-01

    This paper describes an aspect of reflective practice referred to as situated reflective practice. The overarching theory is derived from social theories of structuration and reflexivity. In particular, from Giddens' theory of structuration, which sees social life as an interplay of agency and structure. Discussion of the research reported…

  3. Solar district heating

    International Nuclear Information System (INIS)

    The model presented here analyzes solar district heating systems on the basis of the power supplied at the grid feeding point. Consumption patterns are taken into account only in the form of different preset load curves. Processes are selected in consideration of the following aspects: (1) The design of a solar district heating system (collector surface, storage volume) depends on the expected contribution of solar power to electricity supply. For each of the key years 1989, 2005 and 2020, a low, average and high contribution were investigated, from which design concepts for other supply rates can be derived. (2) Yields and economic efficiency of solar systems also depend on collector sites and consumption patterns. 10 variants each with low and very high contributions of solar power were calculated for the key year 2020. (orig.)

  4. Comparison of manufactured and modeled solar cell

    OpenAIRE

    Strachala, D.; Hylský, J.

    2015-01-01

    The aim of the work is to compare the model of monocrystalline silicon solar cell in PC1D with the real solar cell structure in terms of using a model in manufacture process. Real solar cell was firstly measured and analyzed to determine input parameters for a simulation and then realized in free available PC1D software. Degree of conformity of modeled and real solar cell was in the end established for basic prediction of solar cell parameters before manufacturing process.

  5. A physical mechanism of solar corona heating

    OpenAIRE

    Mirzoeva, I. K.

    2011-01-01

    Time profiles of solar soft X-ray microflares and structure soft X-ray solar corona thermal background are studied on RHESSI data. The observations of 2003 year are analyzed. Decrease fluxe of solar soft X-ray microflares and thermal background of solar corona in the X-ray range 2-15 kev are revealed. The new model of solar corona heating in based on this new data are suggested.

  6. Planar Reflection of Gaseous Detonations

    Science.gov (United States)

    Damazo, Jason Scott

    Pipes containing flammable gaseous mixtures may be subjected to internal detonation. When the detonation normally impinges on a closed end, a reflected shock wave is created to bring the flow back to rest. This study built on the work of Karnesky (2010) and examined deformation of thin-walled stainless steel tubes subjected to internal reflected gaseous detonations. A ripple pattern was observed in the tube wall for certain fill pressures, and a criterion was developed that predicted when the ripple pattern would form. A two-dimensional finite element analysis was performed using Johnson-Cook material properties; the pressure loading created by reflected gaseous detonations was accounted for with a previously developed pressure model. The residual plastic strain between experiments and computations was in good agreement. During the examination of detonation-driven deformation, discrepancies were discovered in our understanding of reflected gaseous detonation behavior. Previous models did not accurately describe the nature of the reflected shock wave, which motivated further experiments in a detonation tube with optical access. Pressure sensors and schlieren images were used to examine reflected shock behavior, and it was determined that the discrepancies were related to the reaction zone thickness extant behind the detonation front. During these experiments reflected shock bifurcation did not appear to occur, but the unfocused visualization system made certainty impossible. This prompted construction of a focused schlieren system that investigated possible shock wave-boundary layer interaction, and heat-flux gauges analyzed the boundary layer behind the detonation front. Using these data with an analytical boundary layer solution, it was determined that the strong thermal boundary layer present behind the detonation front inhibits the development of reflected shock wave bifurcation.

  7. Student Teaching: Reflections of a Relentless Journey

    Science.gov (United States)

    Atiles, Julia; Pinholster, Lauren

    2013-01-01

    This action research article shares the story of a student teacher and the arduous, but rewarding process of self-reflection. The authors integrate real life examples of the implementation of self-reflective strategies of a student teacher with self-efficacy, teacher life cycle, and effectiveness literature to analyze the student teacher's…

  8. Reflectivity: Curricula Expectations and Instructional Realities.

    Science.gov (United States)

    Sorgman, Margo

    1986-01-01

    Reviews the research and writing of several authors who advocated intellectual reflectivity as either a major goal or method of social studies. Analyzes the practical constraints which tended to prevent schools and teachers from adopting reflectivty and makes recommendations for increasing teachers' acceptance of reflectivity. (JDH)

  9. Thin silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hall, R.B.; Bacon, C.; DiReda, V.; Ford, D.H.; Ingram, A.E.; Cotter, J.; Hughes-Lampros, T.; Rand, J.A.; Ruffins, T.R.; Barnett, A.M. [Astro Power Inc., Solar Park, Newark, DE (United States)

    1992-12-01

    The silicon-film design achieves high performance by using a dun silicon layer and incorporating light trapping. Optimally designed thin crystalline solar cells (<50 microns thick) have performance advantages over conventional thick devices. The high-performance silicon-film design employs a metallurgical barrier between the low-cost substrate and the thin silicon layer. Light trapping properties of silicon-film on ceramic solar cells are presented and analyzed. Recent advances in process development are described here.

  10. A tandem parallel plate analyzer

    International Nuclear Information System (INIS)

    By a new modification of a parallel plate analyzer the second-order focus is obtained in an arbitrary injection angle. This kind of an analyzer with a small injection angle will have an advantage of small operational voltage, compared to the Proca and Green analyzer where the injection angle is 30 degrees. Thus, the newly proposed analyzer will be very useful for the precise energy measurement of high energy particles in MeV range. (author)

  11. Simulation Tool for GNSS Ocean Surface Reflections

    DEFF Research Database (Denmark)

    Høeg, Per; von Benzon, Hans-Henrik; Durgonics, Tibor

    2015-01-01

    GNSS coherent and incoherent reflected signals have the potential of deriving large scale parameters of ocean surfaces, as barotropic variability, eddy currents and fronts, Rossby waves, coastal upwelling, mean ocean surfaceheights, and patterns of the general ocean circulation. In the reflection...... International Space Station, are focusing on GNSS ocean reflection measurements. Thus, simulation studies highlighting the assumptions for the data retrievals and the precision and the accuracy of such measurements are of interest for assessing the observational method.The theory of propagation of microwaves in.......Simulated GPS ocean surface reflections will be presented and discussed based on different ocean characteristics.The spectra of the simulated surface reflections will be analyzed and compared with existing observations.The analysis of both the simulated surface reflection signals and the measured reflection...

  12. Understanding reflective practice.

    Science.gov (United States)

    Nicol, Jacqueline Sian; Dosser, Isabel

    2016-05-01

    The Nursing and Midwifery Council (NMC) requires that nurses and midwives use feedback as an opportunity for reflection and learning, to improve practice. The NMC revalidation process stipulates that practitioners provide examples of how they have achieved this. To reflect in a meaningful way, it is important to understand what is meant by reflection, the skills required, and how reflection can be undertaken successfully. Traditionally, reflection occurs after an event encountered in practice. The authors challenge this perception, suggesting that reflection should be undertaken before, during and after an event. This article provides practical guidance to help practitioners use reflective models to write reflective accounts. It also outlines how the reflective process can be used as a valuable learning tool in preparation for revalidation. PMID:27154119

  13. External observer reflections on QBism

    CERN Document Server

    Khrennikov, Andrei

    2015-01-01

    In this short review I present my personal reflections on QBism. I have no intrinsic sympathy neither to QBism nor to subjective interpretation of probability in general. However, I have been following development of QBism from its very beginning, observing its evolution and success, sometimes with big surprise. Therefore my reflections on QBism can be treated as "external observer" reflections. I hope that my representation of this interpretation of quantum mechanics (QM) has some degree of objectivity. It may be useful for researchers who are interested in quantum foundations, but do not belong to the QBism-community, because I tried to analyze essentials of QBism critically (i.e., not just emphasizing its advantages, as in a typical publication of QBists). QBists may be interested as well - in comments of an external observer who monitored development of this approach to QM during last 16 years. The second part of the paper is devoted to interpretations of probability, objective versus subjective, and view...

  14. Solar Energy.

    Science.gov (United States)

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  15. Solar Combisystems

    DEFF Research Database (Denmark)

    Thür, Alexander

    2006-01-01

    This note first introduces what is a solar combisystem, the structure how a solar combisystem is build up and what are criteria’s to evaluate a solar combisystem concept. Further on the main components of a solar combisystem, the main characteristics and possible advantages and disadvantages...... compared to each other are described. It is not the goal of this note to explain the technical details how to design all components of a solar combisystem. This is done during other lectures of the solar course and in other basic courses as well. This note tries to explain how a solar combisystem...

  16. Solar energy

    Science.gov (United States)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  17. Insights on Solar Twins

    Science.gov (United States)

    Sousa Duarte, Tharcisyo Sa e.; Soares da Costa, Jefferson; Dias do Nascimento Júnior, José

    2015-08-01

    The question about how to define a real solar twin are still active. Cayrel de Strobe et al. (1981) defined a solar twin like a star having at the same time the physical parameters, Teff, gravity, bolometric magnitude, microturbulent velocity, and chemical composition. We presented the more extensive sample of solar twins known to date. From these targets we will study the behavior of the solar twins as a function of fundamentals stellar parameters, effective temperature, luminosity, age, convective envelope mass deepening (1 - M*/M⊙), lithium abundance and rotation period. We selected the solar twins from observations with the spectropolarimeters ESPaDOnS at CFHT and the Narval at TBL and also on literature. All objects have high resolution and high signal to noise. Analyze this sample of solar twins will help us to understand how these stars whether located around of the Sun's place. Our preliminary results show that the lithium abundance presents one clear correlation with stellar age. The (1 - M*/M⊙) values obtained through our method provided good agreement with the solar value. The rotation periods allow us to assess the solar twins as a function of gyrochronology.

  18. Variability of Electron Densities in the Low-Altitude Martian Nightside Ionosphere Derived from the Intensity of Marsis AIS Surface Reflections

    Science.gov (United States)

    Nemec, F.; Morgan, D. D.; Gurnett, D. A.

    2014-12-01

    Sounding signals at frequencies higher than the ionospheric peak plasma frequency are not reflected by the ionosphere. Instead they make it to the ground where they are reflected by the planetary surface. We analyze the intensity of the surface reflections measured by the MARSIS ionospheric radar sounder on board the Mars Express spacecraft. Apart from the surface reflectivity, the intensity of the surface reflection is controlled primarily by the signal attenuation during ionospheric propagation. We focus on the nightside region, where the ionospheric densities in the main layer are too low to cause a significant attenuation and allow sampling of the surface reflection at frequencies down to 3 MHz. The attenuation is then expected to occur mainly at lower altitudes (<100 km), where electron-neutral collision frequency is a maximum. The intensity of surface reflections can thus serve as a proxy for the electron density at low altitudes not accessible by the direct MARSIS ionospheric radar sounding. We derive the intensity of surface reflections from all available MARSIS nightside ionograms, and we analyze its variability as a function of relevant controlling factors such as SZA, solar activity, magnetic field magnitude and inclination, and simultaneously observed electron density in the main ionospheric layer. The results obtained are discussed in terms of possible processes affecting the electron densities at low altitudes.

  19. Solar Technology Institute

    International Nuclear Information System (INIS)

    For the past three years, Ken Olson and Johnny Weiss and their staff have been quietly delivering the tools of sustainable development to people in places as diverse (or similar) as Manhattan and the jungles of Colombia. Their delivery vehicle is the Solar Technology Institute, officially launched in May of 1991. Founded on thirty years of combined experience and inspired by Johnny and Ken's most recent work in developing countries, STI reflects its founders' evolving abilities to tackle environmental energy and development challenges on a global scale. This article describes the STI and highlights some of its global activities in education and application of solar technology

  20. An improved prism energy analyzer for neutrons

    International Nuclear Information System (INIS)

    The effects of two improvements of an existing neutron energy analyzer consisting of stacked silicon prism rows are presented. First we tested the effect of coating the back of the prism rows with an absorbing layer to suppress neutron scattering by total reflection and by refraction at small angles. Experiments at HZB showed that this works perfectly. Second the prism rows were bent to shift the transmitted wavelength band to larger wavelengths. At HZB we showed that bending increased the transmission of neutrons with a wavelength of 4.9 Å. Experiments with a white beam at the EROS reflectometer at LLB showed that bending of the energy analyzing device to a radius of 7.9 m allows to shift the transmitted wavelength band from 0 to 9 Å to 2 to 16 Å

  1. An improved prism energy analyzer for neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, J., E-mail: jennifer.schulz@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Ott, F. [Laboratoire Leon Brillouin, Bât 563 CEA Saclay, 91191 Gif sur Yvette Cedex (France); Krist, Th. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

    2014-04-21

    The effects of two improvements of an existing neutron energy analyzer consisting of stacked silicon prism rows are presented. First we tested the effect of coating the back of the prism rows with an absorbing layer to suppress neutron scattering by total reflection and by refraction at small angles. Experiments at HZB showed that this works perfectly. Second the prism rows were bent to shift the transmitted wavelength band to larger wavelengths. At HZB we showed that bending increased the transmission of neutrons with a wavelength of 4.9 Å. Experiments with a white beam at the EROS reflectometer at LLB showed that bending of the energy analyzing device to a radius of 7.9 m allows to shift the transmitted wavelength band from 0 to 9 Å to 2 to 16 Å.

  2. Square and Delta reflection

    OpenAIRE

    Fontanella, Laura; Hayut, Yair

    2016-01-01

    Starting from infinitely many supercompact cardinals, we force a model of ZFC where $\\aleph_{\\omega^2+1}$ satisfies simultaneously a strong principle of reflection, called $\\Delta$-reflection, and a version of the square principle, denoted $\\square(\\aleph_{\\omega^2+1}).$ Thus we show that $\\aleph_{\\omega^2+1}$ can satisfy simultaneously a strong reflection principle and an anti-reflection principle.

  3. Layered magnets: polarized neutron reflection studies

    Energy Technology Data Exchange (ETDEWEB)

    Zabel, H.; Schreyer, A. [Ruhr-Univ. Bochum, Lehrstuhl fuer Experimentalphysik/Festkoerperphysik, Bochum (Germany)

    1996-11-01

    Neutron reflectivity measurements from extended surfaces, thin films and superlattices provide information on the chemical profile parallel to the film normal, including film thicknesses, average composition and interfacial roughness parameters. Reflectivity measurements with polarized neutrons are particularly powerful for analyzing the magnetic density profiles in thin films and superlattices in addition to chemical profiles. The basic theory of polarized neutron reflectivity is provided, followed by some examples and more recent applications concerning polarized neutron reflectivity studies from exchange coupled Fe/Cr superlattices. (author) 5 figs., 13 refs.

  4. CHARACTERIZATION OF TRANSITIONS IN THE SOLAR WIND PARAMETERS

    International Nuclear Information System (INIS)

    The distinction between fast and slow solar wind streams and the dynamically evolved interaction regions is reflected in the characteristic fluctuations of both the solar wind and the embedded magnetic field. High-resolution magnetic field data from the Ulysses spacecraft have been analyzed. The observations show rapid variations in the magnetic field components and in the magnetic field strength, suggesting a structured nature of the solar wind at small scales. The typical sizes of fluctuations cover a broad range. If translated to the solar surface, the scales span from the size of granules (∼103 km) and supergranules (∼104 km) on the Sun down to ∼102 km and less. The properties of the short time structures change in the different types of solar wind. While fluctuations in fast streams are more homogeneous, slow streams present a bursty behavior in the magnetic field variances, and the regions of transition are characterized by high levels of power in narrow structures around the transitions. The probability density functions of the magnetic field increments at several scales reveal a higher level of intermittency in the mixed streams, which is related to the presence of well localized features. It is concluded that, apart from the differences in the nature of fluctuations in flows of different coronal origin, there is a small-scale structuring that depends on the origin of streams themselves but it is also related to a bursty generation of the fluctuations.

  5. Liberating Moral Reflection

    Science.gov (United States)

    Horell, Harold D.

    2013-01-01

    The author argues that if we are to foster life-giving and liberating moral reflection, we must first liberate moral reflection from distortions; specifically, from the distorting effects of moral insensitivity, destructive moral relativism, and confusions resulting from a failure to understand the dynamics of moral reflection. The author proposes…

  6. Solar energy and environmental ethics

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, C.J.

    1984-01-01

    Current directions in the scientific development and advocacy of solar technology emphasize its technical efficiency, its ability to function in place of conventional energy technologies, and measures of its long-run cost effectiveness. Those directions do not consider human experience or the effect of their preoccupation with technical thinking. Even environmental ethics, as it relates to solar energy, and legal aspects of the use of solar energy are biased toward finding fixed solutions to social problems. The German thinker Martin Heidegger argued that meaningful involvement in any saturation depends on one's ability to think clearly and thoroughly. Heidegger's emphasis on thinking and thoughtfulness fits best with ways of using solar energy that are appropriate to both the nature of solar energy and the lifestyles of the users. Truly appropriate use of solar energy requires what Heidegger called a composure toward solar technology, in which solar technology might change to suit new circumstances but not to the point where the user cannot control it. The horizons of solar technology itself are broadened in the context to include scientifically less-sophisticated equipment, and ways of using solar energy that reflect changes in lifestyle and greater awareness of the sun.

  7. Solar Thermal Propulsion Test

    Science.gov (United States)

    1999-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This image, taken during the test, depicts the light being concentrated into the focal point inside the vacuum chamber. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  8. The Solar Dynamos

    Science.gov (United States)

    Cattaneo, F.

    2000-05-01

    Magnetic activity on the Sun presents us with an interesting dichotomy. On large spatial and temporal scales the solar magnetic field displays a remarkable degree of organization. The 11 years cadence of the solar cycle, Hales' polarity law, and the systematic drift of the regions of emergence of active regions towards the equator throughout the solar cycle are all indicative of a powerful organizing process. On small spatial and temporal scales, the Solar magnetic field appears random and chaotic. It is interesting that recent advances in dynamo theory provide us with a unified approach to solar magnetic activity whereby both large and small scales emerge naturally as dynamo processes associated with rotationally constrained and unconstrained scales of motions in the convection zone (or directly below it). According to this view all coherent scales of motions produce magnetic structures of comparable coherence length. Those that are further endowed with lack of reflectional symmetry by virtue of being rotationally constrained are further associated with inverse cascades that can generate magnetic structures on larger scales still. The picture that emerges is one in which dynamo action proceeds on different time scales all over the convection zone. But only in very special regions, like for instance the solar tachocline, is the magnetic field organized on large scales. This idea provides a natural explanation for the origin of active regions, ephemeral regions, and intra--network fields.

  9. Reflection Positive Doubles

    CERN Document Server

    Jaffe, Arthur

    2016-01-01

    Here we introduce reflection positive doubles, a general framework for reflection positivity, covering a wide variety of systems in statistical physics and quantum field theory. These systems may be bosonic, fermionic, or parafermionic in nature. Within the framework of reflection positive doubles, we give necessary and sufficient conditions for reflection positivity. We use a reflection-invariant cone to implement our construction. Our characterization allows for a direct interpretation in terms of coupling constants, making it easy to check in concrete situations. We illustrate our methods with numerous examples.

  10. Investisation on performance of a solar thermophotovoitaic system

    Institute of Scientific and Technical Information of China (English)

    CHEN Xue; XUAN YiMin; HAN YuGe

    2008-01-01

    In the light of the thermo-electric conversion principle, a model for predicting the performance of a solar thermophotovoltaic system is presented. The temperature distributions of the emitter for different concentrator ratios are numerically com-puted and the influence of the concentrator ratio on the system performance is analyzed. Numerical results show that the emitter temperature and the system effi-ciency increase with increase of the concentrator ratio. The effects of some other factors such as the spectral filter, cell temperature, and the reflectivity of the top and bottom surfaces of the emitter on the conversion performance of the STPV system are discussed.

  11. Investigation on performance of a solar thermophotovoltaic system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the light of the thermo-electric conversion principle, a model for predicting the performance of a solar thermophotovoltaic system is presented. The temperature distributions of the emitter for different concentrator ratios are numerically computed and the influence of the concentrator ratio on the system performance is analyzed. Numerical results show that the emitter temperature and the system efficiency increase with increase of the concentrator ratio. The effects of some other factors such as the spectral filter, cell temperature, and the reflectivity of the top and bottom surfaces of the emitter on the conversion performance of the STPV system are discussed.

  12. Black Silicon formation using dry etching for solar cells applications

    International Nuclear Information System (INIS)

    A study on the formation of Black Silicon on crystalline silicon surface using SF6/O2 and SF6/O2/CH4 based plasmas in a reactive ion etching (RIE) system is presented. The effect of the RF power, chamber pressure, process time, gas flow rates, and gas mixtures on the texture of silicon surface has been analyzed. Completely Black Silicon surfaces containing pyramid like structures have been obtained, using an optimized mask-free plasma process. Moreover, the Black Silicon surfaces have demonstrated average values of 1% and 4% for specular and diffuse reflectance respectively, feature that is suitable for the fabrication of low cost solar cells.

  13. Analyzing Valuation Practices through Contracts

    DEFF Research Database (Denmark)

    Tesnière, Germain; Labatut, Julie; Boxenbaum, Eva

    This paper seeks to analyze the most recent changes in how societies value animals. We analyze this topic through the prism of contracts between breeding companies and farmers. Focusing on new valuation practices and qualification of breeding animals, we question the evaluation of difficult...

  14. Analyzing data files in SWAN

    CERN Document Server

    Gajam, Niharika

    2016-01-01

    Traditionally analyzing data happens via batch-processing and interactive work on the terminal. The project aims to provide another way of analyzing data files: A cloud-based approach. It aims to make it a productive and interactive environment through the combination of FCC and SWAN software.

  15. Focussing Image Slicers Refractive and Reflective

    CERN Document Server

    Richardson, E H; Tilleman, T; Crampton, D S; Crampton, David

    1999-01-01

    A number of design options for image slicers for NGST and Gemini are being investigated. These image slicers are all of the focussing type and both refractive and reflective solutions are being explored. One such device, an image slicer that focuses 10 slices on a spectrograph slit is now in operation at the McMath Solar telescope. It consists of three lenslet arrays, and additionally acts as a focal reducer and provides correction for astigmatism of the telescope. A combined refractive and reflective slicer designed for use on NGST delivers near-diffraction limited images for up to 40 slices.

  16. Solution for Improve the Efficiency of Solar Photovoltaic Installation

    Directory of Open Access Journals (Sweden)

    Petru Chioncel

    2013-01-01

    Full Text Available This paper present a solution for improving efficiency of solar photovoltaic installation, realized with fixed solar photovoltaic modules, placed in solar parks or individual installations. The proposed solution to increase the radiation on the solar photovoltaic panels is to use some thin plates covered with a reflective blanket, mounted in front of the solar photovoltaic modules, with the possibility of their adjustment.

  17. Variability of Solar Irradiances Using Wavelet Analysis

    Science.gov (United States)

    Pesnell, William D.

    2007-01-01

    We have used wavelets to analyze the sunspot number, F10.7 (the solar irradiance at a wavelength of approx.10.7 cm), and Ap (a geomagnetic activity index). Three different wavelets are compared, showing how each selects either temporal or scale resolution. Our goal is an envelope of solar activity that better bounds the large amplitude fluctuations form solar minimum to maximum. We show how the 11-year cycle does not disappear at solar minimum, that minimum is only the other part of the solar cycle. Power in the fluctuations of solar-activity-related indices may peak during solar maximum but the solar cycle itself is always present. The Ap index has a peak after solar maximum that appears to be better correlated with the current solar cycle than with the following cycle.

  18. CRADA with United Solar Technologies and Pacific Northwest Laboratory (PNL-021): Thin film materialsfor low-cost high performance solar concentrators

    Science.gov (United States)

    Martin, P. M.; Affinito, J. D.; Gross, M. E.; Bennett, W. D.

    1995-03-01

    The objectives of this project were to develop and evaluate promising low-cost dielectric and polymer-protected thin-film reflective metal coatings to be applied to preformed continuously-curved solar reflector panels to enhance their solar reflectance, and to demonstrate protected solar reflective coatings on preformed solar concentrator panels. The opportunity for this project arose from a search by United Solar Technologies (UST) for organizations and facilities capable of applying reflective coatings to large preformed panels. PNL was identified as being uniquely qualified to participate in this collaborative project.

  19. Nuclear fuel microsphere gamma analyzer

    Science.gov (United States)

    Valentine, Kenneth H.; Long, Jr., Ernest L.; Willey, Melvin G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties.

  20. High Speed AB-Solar Sail

    OpenAIRE

    Bolonkin, A.

    2007-01-01

    The Solar sail is a large thin film used to collect solar light pressure for moving of space apparatus. Unfortunately, the solar radiation pressure is very small about 9 mkN/sq.m at Earth's orbit. However, the light force significantly increases up to 0.2 - 0.35 N/sq.m near the Sun. The author offers his research on a new revolutionary highly reflective solar sail which flyby (after special maneuver) near Sun and attains velocity up to 400 km/sec and reaching far planets of the Solar system i...

  1. A climatology of visible surface reflectance spectra

    Science.gov (United States)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-09-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290-740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment-2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes.

  2. Solar Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar feature datasets contributed by a number of national and private solar observatories located worldwide.

  3. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  4. Solar Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar photographic and illustrated datasets contributed by a number of national and private solar observatories located worldwide....

  5. Solar Sector Structure

    CERN Document Server

    Hudson, Hugh; Hannah, Iain

    2015-01-01

    The interplanetary magnetic field near has a characteristic "sector" structure that reflects its polarity relative to the solar direction. Typically we observe large-scale coherence in these directions, with two or four "away" or "towards" sectors per solar rotation, from any platform in deep space and near the ecliptic plane. In a simple picture, this morphology simply reflects the idea that the sources of the interplanetary field lie mainly in or near the Sun, and that the solar-wind flow enforces a radial component in this field. Although defined strictly via the interplanetary field near one AU, recent evidence confirms that this pattern also appears clearly at the level of the photosphere, with signatures including not only the large-scale structures (e.g., the streamers) but also highly concentrated fields such as those found in sunspots and even solar flares. This association with small-scale fields strengthens at the Hale sector boundary, defining the Hale boundary as the one for which the polarity sw...

  6. Tower-supported solar-energy collector

    Science.gov (United States)

    Selcuk, M. K.

    1977-01-01

    Multiple-collector tower system supports three receiver/concentrators that absorb solar energy reflected from surrounding field of heliostats. System overcomes disadvantages of tower-supported collectors. Booms can be lowered during heavy winds to protect arms and collectors.

  7. A ‘new vantage point’ for observing, analyzing and reflecting on today's cities: URBS. Journal of Urban Studies and Social Sciences Un ‘nuevo mirador’ para observar, analizar y reflexionar sobre las ciudades actuales: URBS. Revista de Estudios Urbanos y Ciencias Sociales

    Directory of Open Access Journals (Sweden)

    Baltasar Fernández-Ramírez

    2011-11-01

    Full Text Available URBS. Journal of Urban Studies and Social Sciences is born with the intention of becoming a 'new viewpoint' of cities worldwide. Our perspective implies a clear commitment regarding the exchange of complex and multiple knowledge around urban studies in social sciences, but also in other technician and creative fields of inquiry originally and worthy interested in contemporary cities. In sum, we propose an interdisciplinary and multilingual space which intends to promote a conscious reflection about thematic topics committed scientifically, ethically and politically with theoretical innovation and epistemological renovation in Social Sciences.

    URBS. Revista de Estudios Urbanos y Ciencias Sociales nace con la voluntad de convertirse en un ‘nuevo mirador’ de las urbes a nivel mundial. Nuestra perspectiva es una clara apuesta para construir un enclave de intercambio de conocimiento complejo y múltiple de los estudios urbanos desde las ciencias sociales, pero también desde otros ámbitos técnicos y creativos que analizan y observan las ciudades contemporáneas de maneras originales y meritorias. En definitiva, un espacio interdisciplinar y multilingüe que promueva una reflexión consciente, haciéndolo además desde ámbitos temáticos comprometidos científica, ética y políticamente con la innovación teórica y la renovación epistemológica de las Ciencias Sociales.

  8. SWIR calibration of Spectralon reflectance factor

    Science.gov (United States)

    Georgiev, Georgi T.; Butler, James J.; Cooksey, Catherine; Ding, Leibo; Thome, Kurtis J.

    2011-11-01

    Satellite instruments operating in the reflective solar wavelength region require accurate and precise determination of the Bidirectional Reflectance Factor (BRF) of laboratory-based diffusers used in their pre-flight and on-orbit radiometric calibrations. BRF measurements are required throughout the reflected-solar spectrum from the ultraviolet through the shortwave infrared. Spectralon diffusers are commonly used as a reflectance standard for bidirectional and hemispherical geometries. The Diffuser Calibration Laboratory (DCaL) at NASA's Goddard Space Flight Center is a secondary calibration facility with reflectance measurements traceable to those made by the Spectral Tri-function Automated Reference Reflectometer (STARR) facility at the National Institute of Standards and Technology (NIST). For more than two decades, the DCaL has provided numerous NASA projects with BRF data in the ultraviolet (UV), visible (VIS) and the Near InfraRed (NIR) spectral regions. Presented in this paper are measurements of BRF from 1475 nm to 1625 nm obtained using an indium gallium arsenide detector and a tunable coherent light source. The sample was a 50.8 mm (2 in) diameter, 99% white Spectralon target. The BRF results are discussed and compared to empirically generated data from a model based on NIST certified values of 6°directional-hemispherical spectral reflectance factors from 900 nm to 2500 nm. Employing a new NIST capability for measuring bidirectional reflectance using a cooled, extended InGaAs detector, BRF calibration measurements of the same sample were also made using NIST's STARR from 1475 nm to 1625 nm at an incident angle of 0° and at viewing angle of 45°. The total combined uncertainty for BRF in this ShortWave Infrared (SWIR) range is less than 1%. This measurement capability will evolve into a BRF calibration service in SWIR region in support of NASA remote sensing missions.

  9. Solar urticaria

    Directory of Open Access Journals (Sweden)

    Srinivas C

    1995-01-01

    Full Text Available A 35-year-old female and a 41-year-old male presented with clinical features suggestive of solar urticaria. The diagnosis of solar urticaria and the effectiveness of a combination of H1 and H2 blocking antihistamines were confirmed by phototesting with a solar simulator

  10. Solar Equipment

    Science.gov (United States)

    1983-01-01

    A medical refrigeration and a water pump both powered by solar cells that convert sunlight directly into electricity are among the line of solar powered equipment manufactured by IUS (Independent Utility Systems) for use in areas where conventional power is not available. IUS benefited from NASA technology incorporated in the solar panel design and from assistance provided by Kerr Industrial Applications Center.

  11. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2016-01-01

    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... without reducing reflection to an effect of the social structures and cultural norms in which it is embedded. Based on the developed theoretical framework, this article analyses how a renaissance ‘mirror for princes’ and contemporary research-based management education mediate reflection. The content of...... the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership...

  12. Phosphorous gettering in acidic textured multicrystalline solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Montesdeoca-Santana, A. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Fraunhofer Institut fuer Solare Energiesysteme ISE, Laboratory and Servicecenter Gelsenkirchen, Auf der Reihe 2, 45884 Gelsenkirchen (Germany); Jimenez-Rodriguez, E.; Diaz-Herrera, B.; Hernandez-Rodriguez, C. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Diaz, B. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Departamento de Energia Fotovoltaica, Instituto Tecnologico y de Energias Renovables. Poligono Industrial de Granadilla s/n, 38600 San Isidro-Granadilla de Abona, S/C de Tenerife (Spain); Rinio, M.; Borchert, D. [Fraunhofer Institut fuer Solare Energiesysteme ISE, Laboratory and Servicecenter Gelsenkirchen, Auf der Reihe 2, 45884 Gelsenkirchen (Germany); Guerrero-Lemus, R. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Fundacion de Estudios de Economia Aplicada, Catedra Focus-Abengoa, Jorge Juan 46, 28001 Madrid (Spain)

    2011-03-15

    The influence of phosphorus gettering is studied in this work applied to an acidic textured multicrystalline silicon substrate. The texturization was achieved with an HF/HNO{sub 3} solution leading to nanostructures on the silicon surface. It has been demonstrated in previous works that this textured surface decreases the reflectance on the solar cell and increases the surface area improving the photon collection and enhancing the short circuit current. The present study investigates the effect on the minority carrier lifetime of the phosphorous diffusion when it is carried out on this textured surface. The lifetime is measured by means microwave photoconductance decay and quasi steady state phototoconductance devices. The diffused textured wafers are used to fabricate solar cells and their electrical parameters are analyzed. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Photospheric Magnetic Free Energy Density of Solar Active Regions

    CERN Document Server

    Zhang, Hongqi

    2016-01-01

    We present the photospheric energy density of magnetic fields in two solar active regions inferred from observational vector magnetograms, and compare it with the possible different defined energy parameters of magnetic fields in the photosphere. We analyze the magnetic fields in active region NOAA 6580-6619-6659 and 11158. It is noticed that the quantity 1/4pi Bn.Bp is an important energy parameter that reflects the contribution of magnetic shear on the difference between the potential magnetic field (Bp) and non-potential one (Bn), and also the contribution to the free magnetic energy near the magnetic neutral lines in the active regions. It is found that the photospheric mean magnetic energy density changes obviously before the powerful solar flares in the active region NOAA 11158, it is consistent with the change of magnetic fields in the lower atmosphere with flares.

  14. Reflection in professional practice

    OpenAIRE

    Hetzner, Stefanie Bianca

    2014-01-01

    The purpose of this thesis is to contribute to the research on professional learning through reflective practice. The main goal is to examine—against the backdrop of workplace changes and errors—individual and contextual factors that are theoretically assumed to influence reflection in the context of professional work. Reflective practice is defined as a retrospective but future- and goal-oriented cognitive-affective process that basically involves (a) the awareness and review of incident...

  15. Solar Indices - Solar Radio Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  16. Using the Sonoran and Libyan Desert test sites to monitor the temporal stability of reflective solar bands for Landsat 7 enhanced thematic mapper plus and Terra moderate resolution imaging spectroradiometer sensors

    Science.gov (United States)

    Angal, Amit; Xiong, Xiaoxiong; Choi, Tae-young; Chander, Gyanesh; Wu, Aisheng

    2010-01-01

    Remote sensing imagery is effective for monitoring environmental and climatic changes because of the extent of the global coverage and long time scale of the observations. Radiometric calibration of remote sensing sensors is essential for quantitative & qualitative science and applications. Pseudo-invariant ground targets have been extensively used to monitor the long-term radiometric calibration stability of remote sensing sensors. This paper focuses on the use of the Sonoran Desert site to monitor the radiometric stability of the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. The results are compared with the widely used Libya 4 Desert site in an attempt to evaluate the suitability of the Sonoran Desert site for sensor inter-comparison and calibration stability monitoring. Since the overpass times of ETM+ and MODIS differ by about 30 minutes, the impacts due to different view geometries or test site Bi-directional Reflectance Distribution Function (BRDF) are also presented. In general, the long-term drifts in the visible bands are relatively large compared to the drift in the near-infrared bands of both sensors. The lifetime Top-of-Atmosphere (TOA) reflectance trends from both sensors over 10 years are extremely stable, changing by no more than 0.1% per year (except ETM+ Band 1 and MODIS Band 3) over the two sites used for the study. The use of a semi-empirical BRDF model can reduce the impacts due to view geometries, thus enabling a better estimate of sensor temporal drifts.

  17. Solar concentrators with adjustable power density distributions

    Energy Technology Data Exchange (ETDEWEB)

    Kleinwaechter, J.

    1977-09-01

    Solar concentrators are described which provide given power density in the absorber. According to the invention, 'semi-optical' lenses and mirrors are used to concentrate the incident solar radiation; these elements image the solar disk not as a point but as an area of constant illumination intensity on the absorber. This is achieved by a functional locus-dependecy of refraction and reflection. For mirror concentration, a differential equation is given which satisfies this functional dependency.

  18. Solar Energy: Solar System Economics.

    Science.gov (United States)

    Knapp, Henry H., III

    This module on solar system economics is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies.…

  19. SCAN: a Fortran syntax analyzer

    International Nuclear Information System (INIS)

    SCAN is a computer program which analyzes the syntax of a Fortran program. It reads statements of a Fortran program, checks the grammatical validity of them, and produces tables of the analyzed results and intermediate codes for further use. SCAN recognizes the Fortran syntax of the Japan Industrial Standards-7000, plus some Fortran-H statements. In this report, the structure of SCAN, the methods used by the SCAN to analyze statements, tables and intermediate Buckus form texts produced by the SCAN, are presented. The SCAN itself is also written in Fortran language and consists of about 5000 statements. By slight modifications the SCAN may be useful for any application which needs analysis operations of Fortran syntax. (author)

  20. Solar energy collector system

    Energy Technology Data Exchange (ETDEWEB)

    Dumbeck, R.F.

    1982-04-13

    Simple flat plate reflectors, preferably compound of a panel with a reflector surface layer laminated thereto, are pivoted to move with the position of the sun and concentrate additional energy on a solar energy collector panel. The array can take a tented or triangular end view shape for closing to protect reflective surfaces from hail or sandstorm, etc. Also the surfaces are provided with a periodically operable surface cleaner to assure long term efficiency even when remotely positioned as on roof top. Low cost present day computers are programmed to track the sun over its seasonal variations by means of simple mechanisms pivoting the reflector plates. The system is self-energizing by means of batteries charged by solar panels accompanying the system. Solar energy is storable in a self-contained water tank for use at night, etc. And efficient energy conversion is attained by means of a stainless steel pipe length extending into the stored water and thermally coupled outside the tank to a solar heated higher than 100* C. Silicon oil circulated through the solar collector. Thus, vaporization is avoided and an effective lowcost simplified thermal energy conversion is effected.

  1. Reuse of the Reflective Light and the Recycle Heat Energy in Concentrated Photovoltaic System

    OpenAIRE

    Hsin-Chien Chen; Liann-Be Chang; Ho-Thea Lin; Ming-Jer Jeng; Lee Chow

    2013-01-01

    A complex solar unit with microcrystalline silicon solar cells placed around the centered GaAs triple junction solar cell has been proposed and carried out. With the same illumination area and intensity, the total resultant power shows that the excess microcrystalline silicon solar cells increase the total output power by 13.2% by absorbing the reflective light from the surface of optical collimators. Furthermore, reusing the residual heat energy generated from the above-mentioned mechanism h...

  2. Loviisa nuclear power plant analyzer

    International Nuclear Information System (INIS)

    The APROS Simulation Environment has been developed since 1986 by Imatran Voima Oy (IVO) and the Technical Research Centre of Finland (VTT). It provides tools, solution algorithms and process components for use in different simulation systems for design, analysis and training purposes. One of its main nuclear applications is the Loviisa Nuclear Power Plant Analyzer (LPA). The Loviisa Plant Analyzer includes all the important plant components both in the primary and in the secondary circuits. In addition, all the main control systems, the protection system and the high voltage electrical systems are included. (orig.)

  3. Analyzing the Grammar of English

    CERN Document Server

    Teschner, Richard V

    2007-01-01

    Analyzing the Grammar of English offers a descriptive analysis of the indispensable elements of English grammar. Designed to be covered in one semester, this textbook starts from scratch and takes nothing for granted beyond a reading and speaking knowledge of English. Extensively revised to function better in skills-building classes, it includes more interspersed exercises that promptly test what is taught, simplified and clarified explanations, greatly expanded and more diverse activities, and a new glossary of over 200 technical terms.Analyzing the Grammar of English is the only English gram

  4. On-orbit characterization of the VIIRS solar diffuser and solar diffuser screen.

    Science.gov (United States)

    Sun, Junqiang; Wang, Menghua

    2015-01-10

    We analyze bidirectional reflectance factors (BRF) of the solar diffuser (SD) and vignetting function (VF) of the SD screen (SDS) for on-board calibration of the visible infrared imaging radiometer suite (VIIRS). Specific focus is placed on the products of the BRF and VF, which are the main inputs for calibration of the SD and its accompanying solar diffuser stability monitor (SDSM), which tracks SD degradation. A set of 14 spacecraft yaw maneuvers for the Suomi National Polar-Orbiting Partnership satellite, which houses the VIIRS instrument, was carefully planned and carried out over many orbits to provide the necessary information on the dependence of VIIRS instrument response on solar angles. Along with the prelaunch measurements for the SDS VF and SD BRF, the absolute form of the BRF-VF product is determined for each of the reflective solar bands (RSB) and the SDSM detectors. Consequently, the absolute form of the SDS VF also is obtained from the RSB and SDSM detectors using the yaw maneuver data. The results show that the BRF-VF product for an RSB is independent of the detector, gain status, and half-angle mirror side. The derived VFs from the RSB and the SDSM detectors also show reasonable agreement with each other, as well as with the prelaunch VF measurements, and further demonstrate only geometrical dependence, which, in this work, is characterized by solar angles. The derived calibration coefficients, called the F-factors, from the application of the derived functions in this study show a significantly improved pattern. A small band-dependent residual seasonal fluctuation on the level of ∼0.2%-0.4% remains in the F-factors for each RSB and is further improved by a corrective function with linear dependence on the solar azimuth angle in the nominal attitude instrument coordinate system to the VF. For satellite ocean color remote sensing, on-orbit instrument calibration and characterization are particularly important for producing accurate and consistent

  5. Composite blade structural analyzer (COBSTRAN) user's manual

    Science.gov (United States)

    Aiello, Robert A.

    1989-01-01

    The installation and use of a computer code, COBSTRAN (COmposite Blade STRuctrual ANalyzer), developed for the design and analysis of composite turbofan and turboprop blades and also for composite wind turbine blades was described. This code combines composite mechanics and laminate theory with an internal data base of fiber and matrix properties. Inputs to the code are constituent fiber and matrix material properties, factors reflecting the fabrication process, composite geometry and blade geometry. COBSTRAN performs the micromechanics, macromechanics and laminate analyses of these fiber composites. COBSTRAN generates a NASTRAN model with equivalent anisotropic homogeneous material properties. Stress output from NASTRAN is used to calculate individual ply stresses, strains, interply stresses, thru-the-thickness stresses and failure margins. Curved panel structures may be modeled providing the curvature of a cross-section is defined by a single value function. COBSTRAN is written in FORTRAN 77.

  6. Color recognition system for urine analyzer

    Science.gov (United States)

    Zhu, Lianqing; Wang, Zicai; Lin, Qian; Dong, Mingli

    2010-08-01

    In order to increase the speed of photoelectric conversion, a linear CCD is applied as the photoelectric converter instead of the traditional photodiode. A white LED is used as the light source of the system. The color information of the urine test strip is transferred into the CCD through a reflecting optical system. It is then converted to digital signals by an A/D converter. The test results of urine analysis are obtained by a data processing system. An ARM microprocessor is selected as the CPU of the system and a CPLD is employed to provide a driving timing for the CCD drive and the A/D converter. Active HDL7.2 and Verilog HDL are used to simulate the driving timing of the CPLD. Experimental results show that the correctness rate of the test results is better than 90%. The system satisfies the requirements of the color information collection of urine analyzer.

  7. Model for reflection and transmission matrices of nanowire end facets

    Science.gov (United States)

    Svendsen, Guro K.; Weman, Helge; Skaar, Johannes

    2011-05-01

    Nanowires show a large potential for various electro-optical devices, such as light emitting diodes, solar cells, and nanowire lasers. We present a method developed to calculate the modal reflection and transmission matrix at the end facets of a waveguide of arbitrary cross-section, resulting in a generalized version of the Fresnel equations. The reflection can be conveniently computed using fast Fourier transforms once the waveguide modes are known. We demonstrate that the reflection coefficient is qualitatively described by two main parameters: the modal field confinement and the average Fresnel reflection of the plane waves constituting the waveguide mode.

  8. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus, Nina

    2011-01-01

    Reflective monitoring of research practices is essential. However, we often lack formal training in the practices of doing action research, and descriptions of actual inquiry practice are seldom included in publications. Our aim is to provide a glimpse of self-reflective practices based on our...

  9. Reflecting Magnon Bound States

    CERN Document Server

    Ahn, C; Rey, S J

    2008-01-01

    In N=4 super Yang-Mills spin chain, we compute reflection amplitudes of magnon bound-state off giant graviton. We first compute the reflection amplitude off Y=0 brane boundary and compare it with the scattering amplitude between two magnon bound-states in the bulk. We find that analytic structure of the two amplitudes are intimately related each other: the boundary reflection amplitude is a square-root of the bulk scattering amplitude. Using such relation as a guide and taking known results at weak and strong coupling limits as inputs, we find the reflection amplitude of an elementary magnon off Z=0 giant graviton boundary. The reflection phase factor is shown to solve crossing and unitarity relations. We then compute the reflection amplitude of magnon bound-state off the Z=0 brane boundary and observe that its analytic structures are again intimately related to the bulk scattering and the Y=0 boundary reflection amplitudes. We also take dyonic giant magnon limit of these reflection amplitudes and confirm tha...

  10. Earth's Reflection: Albedo

    Science.gov (United States)

    Gillette, Brandon; Hamilton, Cheri

    2011-01-01

    When viewing objects of different colors, you might notice that some appear brighter than others. This is because light is reflected differently from various surfaces, depending on their physical properties. The word "albedo" is used to describe how reflective a surface is. The Earth-atmosphere has a combined albedo of about 30%, a number that is…

  11. Solar activity and terrestrial climate: an analysis of some purported correlations

    DEFF Research Database (Denmark)

    Laut, Peter

    2003-01-01

    Hemisphere land temperatures. These hypotheses play an important role in the scientific as well as in the public debate about the possibility or reality of a man-made global climate change. I have analyzed a number of published graphs which have played a major role in these debates and which have been......The last decade has seen a revival of various hypotheses claiming a strong correlation between solar activity and a number of terrestrial climate parameters: Links between cosmic rays and cloud cover, first total cloud cover and then only low clouds, and between solar cycle lengths and Northern...... existence of important links between solar activity and terrestrial climate. Such links have over the years been demonstrated by many authors. The sole objective of the present analysis is to draw attention to the fact that some of the widely publicized, apparent correlations do not properly reflect the...

  12. Study on a Mid-Temperature Trough Solar Collector with Multisurface Concentration

    Directory of Open Access Journals (Sweden)

    Zhengliang Li

    2015-01-01

    Full Text Available A new trough solar concentrator which is composed of multiple reflection surfaces is developed in this paper. The concentrator was analyzed firstly by using optical software. The variation curves of the collecting efficiency affected by tracking error and the deviation angle were given out. It is found that the deviation tolerance for the collector tracking system is about 8 degrees when the receiver is a 90 mm flat. The trough solar concentrators were tested under real weather conditions. The experiment results indicate that, the new solar concentrator was validated to have relative good collecting efficiency, which can be more than 45 percent when it operated in more 145°C. It also has the characteristics of rdust, wind, and snow resistance and low tracking precision requirements.

  13. Solar observations with Rio de Janeiro Danjon astrolabe: diameter variations and its correlations (1998-2000)

    CERN Document Server

    Neto, Eugênio Reis

    2013-01-01

    This work has aimed to analyze the 1998 to 2000 campaign of solar diameter surveying. The employed instrument was a Danjon astrolabe, at the Observat\\'orio Nacional campus, and specially modified for the solar observations. During the time lapse, 10807 independent measurements of the solar diameter were made, Eastwards and Westwards from the local meridian and evenly distributed. An image treatment has been devised to account for the camera dark current and flat field, using IRAF routines. A study of the observational conditions upon the final outcome was made. The mean temperature at the observation is shown as the most influential parameter upon the final result. Next to it also the temperature variation, the Fried's factor, and the standard deviation of the reflected parabola presented a minor and complex degree of influence. The derived corrections are of the order of hundredths of arc seconds, thus being tenfold smaller than the typical error of one observation. The mean semidiameter for the time lapse (...

  14. Portable pulse height analyzing system

    International Nuclear Information System (INIS)

    Low power, battery operated, compact Portable Pulse Height Analyzing System/Multi Channel Analyzer (PMCA) has been designed and developed for monitoring the various low activity radioisotopes in situ. PMCA can also be used in mobile radiation monitoring vans, wherein, gamma spectrum data collected at different locations can be stored in the battery backed RAM disk and down-loaded on to the PC via a serial link. Designed primarily for measurement and analysis of isotope activity and for field experiments, it can be used with most of the radiation detectors used for pulse height spectrum analysis. PMCA is built around embedded PC hardware architecture wherein all the cards are made with state of the art technology with extensive use of SMT and ASICS. PMCA provides features comparable with standard laboratory models and enables computation of integral area, background area, net peak area, FWHM, peak centroid and energy calibration in the field. This paper describes Portable Pulse Height Analyzing System with focus on following features: a) Hardware implementation of well-known multi channel analyzer technique using embedded PC hardware architecture. b) Software implementation of spectrum acquisition and analysis using high level language namely, C. (author)

  15. Analyzing Software Piracy in Education.

    Science.gov (United States)

    Lesisko, Lee James

    This study analyzes the controversy of software piracy in education. It begins with a real world scenario that presents the setting and context of the problem. The legalities and background of software piracy are explained and true court cases are briefly examined. Discussion then focuses on explaining why individuals and organizations pirate…

  16. Helping Students Analyze Business Documents.

    Science.gov (United States)

    Devet, Bonnie

    2001-01-01

    Notes that student writers gain greater insight into the importance of audience by analyzing business documents. Discusses how business writing teachers can help students understand the rhetorical refinements of writing to an audience. Presents an assignment designed to lead writers systematically through an analysis of two advertisements. (SG)

  17. Software-Design-Analyzer System

    Science.gov (United States)

    Tausworthe, Robert C.

    1991-01-01

    CRISP-90 software-design-analyzer system, update of CRISP-80, is set of computer programs constituting software tool for design and documentation of other software and supporting top-down, hierarchical, modular, structured methodologies for design and programming. Written in Microsoft QuickBasic.

  18. FORTRAN Static Source Code Analyzer

    Science.gov (United States)

    Merwarth, P.

    1984-01-01

    FORTRAN Static Source Code Analyzer program, SAP (DEC VAX version), automatically gathers statistics on occurrences of statements and structures within FORTRAN program and provides reports of those statistics. Provisions made for weighting each statistic and provide an overall figure of complexity.

  19. Reflecting on Čerenkov reflections

    Science.gov (United States)

    Fargion, D.; Gaug, M.; Oliva, P.

    2008-05-01

    MAGIC, as well as HESS and VERITAS, is a Čerenkov Telescope unveiling γ-ray sources above 60 GeV at vertical within noisy (hadronic) airshowering sky. These telescopes while facing the horizons may reveal rarest blazing UHECR as well as far fluorescence tails of downward PeV-EeV hadronic airshowers. Few of these inclined airshowers blazing on axis are spread by the geomagnetic field into twin spots. These twin flashes and their morphology may tag the UHECR origination site. There is a rich window of such reflecting Čerenkov lights visible by Telescopes on top of Mountains as MAGIC (and partially VERITAS): the reflections from the nearby ground (possibly enhanced by rain or snow, ice white cover), from the Sea and from the cloudy sky; in particular, these cloudy sheets may lay above or below the observer. MAGIC looking downward to the clouds or the snow, may well reveal blazing Moliere disks diffusing Čerenkov spots (few events per night). Because of geomagnetic forces and splitting of the inclined air-shower, one should reveal for the first time (at tens PeV or above) Čerenkov airshowers whose flashes are skimming the MAGIC nearby Sea and opened into twin spots. Their morphology may tag the UHECR origination, its consequent cross-section and composition. Magic telescopes looking upward into cloudy sky may observe very rare up-going UHE Tau, originated by UHE PeVs neutrinos skimming earth, air-showering into sky, reflecting into clouds. In particular Glashow resonant antineutrinos electron hitting into Earth electrons may lead to gauged boson W-, whose decay (inside the Earth) may produce a τ + bar nuτ [3], which later escape and decay in air is producing Čerenkov lights; these flashes may blaze into the clouds above MAGIC as upward dot spots. The Magic energy threshold for such UHE Neutrinos showers rises to PeV values. EeV UHE tau neutrinos by guaranteed GZK UHECR secondaries [6, 16], via the muon-tau flavor mixing, may skim the Earth, produce UHE tau

  20. Evaluation of Surface Slope Irregularity in Linear Parabolic Solar Collectors

    Directory of Open Access Journals (Sweden)

    F. Francini

    2012-01-01

    Full Text Available The paper describes a methodology, very simple in its application, for measuring surface irregularities of linear parabolic collectors. This technique was principally developed to be applied in cases where it is difficult to use cumbersome instruments and to facilitate logistic management. The instruments to be employed are a digital camera and a grating. If the reflector surface is defective, the image of the grating, reflected on the solar collector, appears distorted. Analyzing the reflected image, we can obtain the local slope of the defective surface. These profilometric tests are useful to identify and monitor the mirror portions under mechanical stress and to estimate the losses caused by the light rays deflected outside the absorber.

  1. Analyzing and Interpreting Historical Sources

    DEFF Research Database (Denmark)

    Kipping, Matthias; Wadhwani, Dan; Bucheli, Marcelo

    2014-01-01

    on social scientific methods as well as the practice and reflections of historians, the chapter describes analytical and interpretive process based on three basic elements, illustrating them with exemplars from management research: source criticism to identify possible biases and judge the extent to......This chapter outlines a methodology for the interpretation of historical sources, helping to realize their full potential for the study of organization, while overcoming their challenges in terms of distortions created by time, changes in context, and selective production or preservation. Drawing...... which a source can be trusted to address the research question; triangulation with additional sources to confirm or question an interpretation and strengthen the overall findings; hermeneutics to relate sources to their original contexts and make their interpretation by a researcher today more robust...

  2. Reflection and teaching: a taxonomy

    OpenAIRE

    Vos, Henk; Cowan, John

    2009-01-01

    A major problem in teaching reflection is that educational objectives for reflection in terms of student behaviour are lacking. Therefore a taxonomy of reflection has been developed based on Bloom’s taxonomy. Reflective assignments can then be better focused on any chosen educational objectives. The act of reflection has been analysed and abstracted from goal, content, context, means, and moment of reflecting. Reflection was operationalised as answering reflective questions. Bloom’s taxonomy ...

  3. Review of Teacher's Teaching Reflection

    Institute of Scientific and Technical Information of China (English)

    王爽爽

    2015-01-01

    Teacher's teaching reflection has become the core focus in school.However,there are different understandings of the concept of teacher's teaching reflection.The paper introduces and compares different understandings of the concept of teachers' teaching reflection.Based on the summarizing of the concept on reflection and teaching reflection,this paper tries to provide reference for the teacher's teaching reflection.

  4. The Statistical Loop Analyzer (SLA)

    Science.gov (United States)

    Lindsey, W. C.

    1985-01-01

    The statistical loop analyzer (SLA) is designed to automatically measure the acquisition, tracking and frequency stability performance characteristics of symbol synchronizers, code synchronizers, carrier tracking loops, and coherent transponders. Automated phase lock and system level tests can also be made using the SLA. Standard baseband, carrier and spread spectrum modulation techniques can be accomodated. Through the SLA's phase error jitter and cycle slip measurements the acquisition and tracking thresholds of the unit under test are determined; any false phase and frequency lock events are statistically analyzed and reported in the SLA output in probabilistic terms. Automated signal drop out tests can be performed in order to trouble shoot algorithms and evaluate the reacquisition statistics of the unit under test. Cycle slip rates and cycle slip probabilities can be measured using the SLA. These measurements, combined with bit error probability measurements, are all that are needed to fully characterize the acquisition and tracking performance of a digital communication system.

  5. Methods for Analyzing Social Media

    DEFF Research Database (Denmark)

    Jensen, Jakob Linaa

    2013-01-01

    Social media is becoming increasingly attractive for users. It is a fast way to communicate ideas and a key source of information. It is therefore one of the most influential mediums of communication of our time and an important area for audience research. The growth of social media invites many...... new questions such as: How can we analyze social media? Can we use traditional audience research methods and apply them to online content? Which new research strategies have been developed? Which ethical research issues and controversies do we have to pay attention to? This book focuses on research...... strategies and methods for analyzing social media and will be of interest to researchers and practitioners using social media, as well as those wanting to keep up to date with the subject....

  6. New Vacuum Solar Telescope

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    With its pure aperture up to 985mm, the New Vacuum Solar Telescope of China (NVST) has become the world's biggest vacuum solar telescope. The main science task of NVST is the high-resolution observation of photosphere and chromosphere including their fine structure of magnetic field on the sun. The NVST was equipped with many new technologies and powerful instruments, such as an adaptive optical system, a polarization analyzer, two vertical spectrographs, a high-resolution image system and a very narrow Ha filter (0.125A).

  7. Methodology for analyzing risk at nuclear facilities

    International Nuclear Information System (INIS)

    Highlights: • A new methodology for evaluating the risk at nuclear facilities was developed. • Five measures reflecting all factors that should be concerned to assess risk were developed. • The attributes on NMAC and nuclear security culture are included as attributes for analyzing. • The newly developed methodology can be used to evaluate risk of both existing facility and future nuclear system. - Abstract: A methodology for evaluating risks at nuclear facilities is developed in this work. A series of measures is drawn from the analysis of factors that determine risks. Five measures are created to evaluate risks at nuclear facilities. These include the legal and institutional framework, material control, physical protection system effectiveness, human resources, and consequences. Evaluation attributes are developed for each measure and specific values are given in order to calculate the risk value quantitatively. Questionnaires are drawn up on whether or not a state has properly established a legal and regulatory framework (based on international standards). These questionnaires can be a useful measure for comparing the status of the physical protection regime between two countries. Analyzing an insider threat is not an easy task and no methodology has been developed for this purpose. In this study, attributes that could quantitatively evaluate an insider threat, in the case of an unauthorized removal of nuclear materials, are developed by adopting the Nuclear Material Accounting & Control (NMAC) system. The effectiveness of a physical protection system, P(E), could be analyzed by calculating the probability of interruption, P(I), and the probability of neutralization, P(N). In this study, the Tool for Evaluating Security System (TESS) code developed by KINAC is used to calculate P(I) and P(N). Consequence is an important measure used to analyze risks at nuclear facilities. This measure comprises radiological, economic, and social damage. Social and

  8. Source-Code-Analyzing Program

    Science.gov (United States)

    Manteufel, Thomas; Jun, Linda

    1991-01-01

    FORTRAN Static Source Code Analyzer program, SAP, developed to gather statistics automatically on occurrences of statements and structures within FORTRAN program and provide for reporting of those statistics. Provisions made to weight each statistic and provide overall figure of complexity. Statistics, as well as figures of complexity, gathered on module-by-module basis. Overall summed statistics also accumulated for complete input source file. Written in FORTRAN IV.

  9. Value reflected health education

    DEFF Research Database (Denmark)

    Wistoft, Karen; Nordentoft, Helle Merete

    2011-01-01

    This article examines the impact of a value-reflected approach in health education by demonstrating the nature of professional competence development connected to this approach. It is based on findings from two three-year health educational development projects carried out by school health nurses...... and researchers at primary schools in Denmark from 2004-2009. We argue for the importance of reflecting on values in school health nursing in order to navigate between human values and values deriving from medicine. Our studies demonstrate that value clarification, peer observation and reflective spaces at work...... develop pedagogical competences in health education improving school childrens’ health....

  10. Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach

    Science.gov (United States)

    Cheung, Mike W.-L.; Jak, Suzanne

    2016-01-01

    Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists—and probably the most crucial one—is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study. PMID:27242639

  11. Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach

    Directory of Open Access Journals (Sweden)

    Mike W.-L. Cheung

    2016-05-01

    Full Text Available Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists – and probably the most crucial one – is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study.

  12. Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach.

    Science.gov (United States)

    Cheung, Mike W-L; Jak, Suzanne

    2016-01-01

    Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists-and probably the most crucial one-is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study. PMID:27242639

  13. The Characterization of Deep Convective Cloud Albedo as a Calibration Target Using MODIS Reflectances

    Science.gov (United States)

    Doelling, David R.; Hong, Gang; Morstad, Daniel; Bhatt, Rajendra; Gopalan, Arun; Xiong, Jack

    2010-01-01

    There are over 25 years of historical satellite data available to climate analysis. The historical satellite data needs to be well calibrated, especially in the visible, where there is no onboard calibration on operational satellites. The key to the vicarious calibration of historical satellites relies on invariant targets, such as the moon, Dome C, and deserts. Deep convective clouds (DCC) also show promise of being a stable invariant or predictable target viewable by all satellites, since they behave as solar diffusers. However DCC have not been well characterized for calibration. Ten years of well-calibrated MODIS is now available. DCC can easily be identified using IR thresholds, where the IR calibration can be traced to the onboard black-bodies. The natural variability of DCC albedo will be analyzed geographically and seasonally, especially difference of convection initiated over land or ocean. Functionality between particle size and ozone absorption with DCC albedo will be examined. Although DCC clouds are nearly Lambertion, the angular distribution of reflectances will be sampled and compared with theoretical models. Both Aqua and Terra MODIS DCC angular models will be compared for consistency. Normalizing angular geostationary DCC reflectances, which were calibrated against MODIS, with SCIAMACHY spectral reflectances and comparing them to MODIS DCC reflectances will inspect the usage of DCC albedos as an absolute calibration target.

  14. Asymmetric light reflectance from metal nanoparticle arrays on dielectric surfaces

    OpenAIRE

    Huang, K.; Pan, W.; Zhu, J. F.; Li, J.C.; Gao, N; Liu, C; Ji, L.; Yu, E. T.; Kang, J Y

    2015-01-01

    Asymmetric light reflectance associated with localized surface plasmons excited in metal nanoparticles on a quartz substrate is observed and analyzed. This phenomenon is explained by the superposition of two waves, the wave reflected by the air/quartz interface and that reflected by the metal nanoparticles, and the resulting interference effects. Far field behavior investigation suggests that zero reflection can be achieved by optimizing the density of metal nanoparticles. Near field behavior...

  15. Research of commercial bifacial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Tiantian; Li, Hongbo [Shanghai Solar Energy Research Center (China); Li, Wennan; Guo, Wenlin [Shanghai Perfect Energy (China); Chen, Mingbo [Shanghai Institute of Space Power-Sources (China)

    2008-07-01

    Because of the special finger shape and junction structure, bifacial silicon solar cells could receive sunlight from both sides. So the cells can absorb much sunlight, have less strict require for installation, and have higher conversion efficiency. We have done research in commercial bifacial silicon solar cells. We designed the bifacial silicon solar cells with realizable structure and high conversion efficiency. We designed and realized proper technics path, which are used to fabricate these bifacial solar cells. The boron backfield is used. The anti-reflection coating and finger contact are fabricated on both surfaces of the solar cells, so the cells have different contact structure. Meanwhile, we realized ohmic contact between finger contacts and surface of solar cells on both sides. We successfully produced the bifacial silicon solar cells with the front and rear efficiencies exceed 15% and 9%(AM1.5, 25 C), respectively, and which can be produced in large-scale. (orig.)

  16. Solar Photovoltaic

    OpenAIRE

    Wang, Chen; Lu, Yuefeng

    2016-01-01

    In the 21st century, human demand for new energy sources is urgent, because the traditional fossil energy is unable to meet human needs, and the fossil resource will make pollution, in this situation, solar energy gradually into the vision of scientists. As science advances, humans can already extensive use of solar energy to generate electricity. Solar energy is an inexhaustible and clean energy. In the global energy crisis, environmental pollution is the growing problem of today. The us...

  17. Reflective Journal Writing on the Way to Becoming Teachers

    Directory of Open Access Journals (Sweden)

    Feyza Doyran

    2013-03-01

    Full Text Available In this qualitative research study, the purpose was to analyze the reflective journal entries of the 26 pre-service teachers attending the teacher education department of a state university. These teacher candidates were asked to write their reflections on a weekly basis during the “school experience” course in the fall semester. Twelve weekly entries and the end of the year reflection reports of these pre-service teachers (338 documents all together were analyzed according to the contents; similar issues were coded; common themes were found; in the second phase, the findings were analyzed again in the light of reflective practice research to find out about the learning experiences of the pre-service teachers and to analyze in which stage of reflective practice their entries mostly fell into. The results revealed that pre-service teachers benefitted from keeping reflective journals and their reflections mostly fell under the “interpersonal stage” and did not have many comments reflecting the other stages which were procedural and conceptual. The results show that in order for the pre-service teachers to gain more awareness through reflective writing, they need to be trained on how to write reflections effectively and on the different stages related to the reflective practice.

  18. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus-Rødje, Nina

    2011-01-01

    Reflective monitoring of research practices is essential. However, we often lack formal training in the practices of doing action research, and descriptions of actual inquiry practice are seldom included in publications. Our aim is to provide a glimpse of self-reflective practices based on our...... experience of enacting action research. Our engagement in a large action research project brought about many dilemmas and uncertainties related to our roles and interventions. We focus on these uncertainties as a way of opening the ?black box? of action research ?in the making?. We conceptualize a...... methodological reflective approach that provides space for taking seriously uncertainties experienced in the field as these can be a catalyst for learning and sharpening our theoretical and empirical skills as action researchers. Through first-person inquiry, we investigate how our reflective conversations...

  19. Andreev reflection in graphene

    Science.gov (United States)

    Beenakker, Carlo

    2007-03-01

    Relativity and superconductivity have no common ground in ordinary matter, because the velocity of electrons is only a small fraction of the velocity of light. The unusual band structure of a single layer of carbon atoms (graphene) contains negatively and positively charged particles that move as relativistic electrons and positrons. The electron-like particles in the conduction band can be converted into positron-like particles in the valence band when they are reflected by a superconductor. (The missing charge of 2e enters the superconductor as a Cooper pair.) This interband reflection process can be distinguished from the usual intraband Andreev reflection, because the reflection angle has the opposite sign. A new phenomenology of graphene--superconductor junctions is predicted, including an anomalous scaling of the supercurrent with the length of the junction and the existence of charge-neutral modes propagating along the interface.

  20. The security analyzer, a security analyzer program written in Prolog

    International Nuclear Information System (INIS)

    A technique has been developed to characterize a nuclear facility and measure the strengths and weaknesses of the physical protection system. It utilizes the artificial intelligence capabilities available in the prolog programming language to probe a facility's defenses and find potential attack paths that meet designated search criteria. As sensors or barriers become inactive due to maintenance, failure, or inclement weather conditions, the protection system can rapidly be reanalyzed to discover weaknesses that would need to be strengthened by alternative means. Conversely, proposed upgrades and enhancements can be easily entered into the database and their effect measured against a variety of potential adversary attacks. Thus the security analyzer is a tool that aids the protection planner as well as the protection operations staff

  1. Thoughts on Reflection (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2010-06-01

    Full Text Available There has been some acknowledgement in the published literature that reflection is a crucial element of the evidence based library and information practice (EBLIP model we have adopted (Booth 2004, 2006; Grant 2007; Helliwell 2007. As we work through a problem and try to incorporate the best available evidence into our decision making, reflection is required at several stages, including the very identification of the problem through to our assessment of the process itself and what we have learned in order to inform future practice. However, reflection and reflective writing have not fully been integrated into the process we espouse, and very little has been done to look more closely at this element of the model and how it can be integrated into professional learning.In a recently published research article, Sen (2010 confirms the relationship between reflection and several aspects of professional practice. These include critical review and decision making, two aspects that are tied closely to the evidence based process. Sen notes: Students were more likely to show evidence of learning, self‐development, the ability to review issues crucially, awareness of their own mental functions, ability to make decision [sic] and being empowered when they had mastered the art of reflective practice and the more deeply analytical reflective writing. (p.84 EBLIP (the journal tries to incorporate elements of reflection within the articles we publish. While we clearly believe in the need for our profession to do quality research and publish that research so that it can be accessible to practitioners, we also know that research cannot be looked at in isolation. Our evidence summaries are one way of reflecting critically on previously published research, and in the same vein, our classics bring older research studies back to the foreground. This work needs to continue to be discussed and looked at for its impact on our profession.More directly, the Using

  2. Trace Gas Analyzer (TGA) program

    Science.gov (United States)

    1977-01-01

    The design, fabrication, and test of a breadboard trace gas analyzer (TGA) is documented. The TGA is a gas chromatograph/mass spectrometer system. The gas chromatograph subsystem employs a recirculating hydrogen carrier gas. The recirculation feature minimizes the requirement for transport and storage of large volumes of carrier gas during a mission. The silver-palladium hydrogen separator which permits the removal of the carrier gas and its reuse also decreases vacuum requirements for the mass spectrometer since the mass spectrometer vacuum system need handle only the very low sample pressure, not sample plus carrier. System performance was evaluated with a representative group of compounds.

  3. Fuel analyzer; Analisador de combustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Cozzolino, Roberval [RS Motors, Indaiatuba, SP (Brazil)

    2008-07-01

    The current technology 'COMBUSTIMETRO' aims to examine the fuel through performance of the engine, as the role of the fuel is to produce energy for the combustion engine in the form of which is directly proportional to the quality and type of fuel. The 'COMBUSTIMETRO' has an engine that always keeps the same entry of air, fuel and fixed point of ignition. His operation is monitored by sensors (Sonda Lambda, RPM and Gases Analyzer) connected to a processor that performs calculations and records the information, generate reports and graphs. (author)

  4. Truck acoustic data analyzer system

    Science.gov (United States)

    Haynes, Howard D.; Akerman, Alfred; Ayers, Curtis W.

    2006-07-04

    A passive vehicle acoustic data analyzer system having at least one microphone disposed in the acoustic field of a moving vehicle and a computer in electronic communication the microphone(s). The computer detects and measures the frequency shift in the acoustic signature emitted by the vehicle as it approaches and passes the microphone(s). The acoustic signature of a truck driving by a microphone can provide enough information to estimate the truck speed in miles-per-hour (mph), engine speed in rotations-per-minute (RPM), turbocharger speed in RPM, and vehicle weight.

  5. A solar module fabrication process for HALE solar electric UAV's

    Science.gov (United States)

    Carey, P. G.; Aceves, R. C.; Colella, N. J.; Williams, K. A.; Sinton, R. A.; Glenn, G. S.

    1994-12-01

    We describe a fabrication process used to manufacture high power-to-weight-ratio flexible solar array modules for use on high-altitude-long-endurance (HALE) solar-electric unmanned air vehicles (UAV's). These modules have achieved power-to-weight ratios of 315 and 396 W/kg for 150 micron-thick monofacial and 110 micron-thick bifacial silicon solar cells, respectively. These calculations reflect average module efficiencies of 15.3% (150 micron) and 14.7% (110 micron) obtained from electrical tests performed by Spectrolab, Inc. under AMO global conditions at 25 C, and include weight contributions from all module components (solar cells, lamination material, bypass diodes, interconnect wires, and adhesive tape used to attach the modules to the wing). The fabrication, testing, and performance of 32 sq m of these modules is described.

  6. A solar module fabrication process for HALE solar electric UAVs

    Energy Technology Data Exchange (ETDEWEB)

    Carey, P.G.; Aceves, R.C.; Colella, N.J.; Williams, K.A. [Lawrence Livermore National Lab., CA (United States); Sinton, R.A. [Private Consultant, San Jose, CA (United States); Glenn, G.S. [Spectrolab, Inc., Sylmar, CA (United States)

    1994-12-12

    We describe a fabrication process used to manufacture high power-to-weight-ratio flexible solar array modules for use on high-altitude-long-endurance (HALE) solar-electric unmanned air vehicles (UAVs). These modules have achieved power-to-weight ratios of 315 and 396 W/kg for 150{mu}m-thick monofacial and 110{mu}m-thick bifacial silicon solar cells, respectively. These calculations reflect average module efficiencies of 15.3% (150{mu}m) and 14.7% (110{mu}m) obtained from electrical tests performed by Spectrolab, Inc. under AMO global conditions at 25{degrees}C, and include weight contributions from all module components (solar cells, lamination material, bypass diodes, interconnect wires, and adhesive tape used to attach the modules to the wing). The fabrication, testing, and performance of 32 m{sup 2} of these modules will be described.

  7. Solar cell element

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Akihiko; Matsumoto, Hitoshi; Uda, Hiroshi; Komatsu, Yasumitsu; Ikegami, Kiyoharu.

    1989-05-18

    In the existing CdS/CdTe-based solar cell element, nothing is formed except the component effective for generating electromotive force and the components necessary for leading, collecting and extracting the generated electricity, hence even when the element shows deterioration of its performance during its usage, it has been difficult to analyze the above situation. In addition, it has also a defect that its characteristic such as the transfer efficiency in the neighborhood of its glass substrate in connection also with its manufacturing process. In order to solve the above problematical points, this invention proposes, with regard to a CdS-based solar cell element composed by forming a thin film on its substrate, to make a blank space on the above substrate and form thereon a thin film which composes the solar cell element concerned alone or in a piling up manner. 4 figs.

  8. COBSTRAN - COMPOSITE BLADE STRUCTURAL ANALYZER

    Science.gov (United States)

    Aiello, R. A.

    1994-01-01

    The COBSTRAN (COmposite Blade STRuctural ANalyzer) program is a pre- and post-processor that facilitates the design and analysis of composite turbofan and turboprop blades, as well as composite wind turbine blades. COBSTRAN combines composite mechanics and laminate theory with a data base of fiber and matrix properties. As a preprocessor for NASTRAN or another Finite Element Method (FEM) program, COBSTRAN generates an FEM model with anisotropic homogeneous material properties. Stress output from the FEM program is provided as input to the COBSTRAN postprocessor. The postprocessor then uses the composite mechanics and laminate theory routines to calculate individual ply stresses, strains, interply stresses, thru-the-thickness stresses and failure margins. COBSTRAN is designed to carry out the many linear analyses required to efficiently model and analyze blade-like structural components made of multilayered angle-plied fiber composites. Components made from isotropic or anisotropic homogeneous materials can also be modeled as a special case of COBSTRAN. NASTRAN MAT1 or MAT2 material cards are generated according to user supplied properties. COBSTRAN is written in FORTRAN 77 and was implemented on a CRAY X-MP with a UNICOS 5.0.12 operating system. The program requires either COSMIC NASTRAN or MSC NASTRAN as a structural analysis package. COBSTRAN was developed in 1989, and has a memory requirement of 262,066 64 bit words.

  9. Managing healthcare information: analyzing trust.

    Science.gov (United States)

    Söderström, Eva; Eriksson, Nomie; Åhlfeldt, Rose-Mharie

    2016-08-01

    Purpose - The purpose of this paper is to analyze two case studies with a trust matrix tool, to identify trust issues related to electronic health records. Design/methodology/approach - A qualitative research approach is applied using two case studies. The data analysis of these studies generated a problem list, which was mapped to a trust matrix. Findings - Results demonstrate flaws in current practices and point to achieving balance between organizational, person and technology trust perspectives. The analysis revealed three challenge areas, to: achieve higher trust in patient-focussed healthcare; improve communication between patients and healthcare professionals; and establish clear terminology. By taking trust into account, a more holistic perspective on healthcare can be achieved, where trust can be obtained and optimized. Research limitations/implications - A trust matrix is tested and shown to identify trust problems on different levels and relating to trusting beliefs. Future research should elaborate and more fully address issues within three identified challenge areas. Practical implications - The trust matrix's usefulness as a tool for organizations to analyze trust problems and issues is demonstrated. Originality/value - Healthcare trust issues are captured to a greater extent and from previously unchartered perspectives. PMID:27477934

  10. Solar and terrestrial physics. [effects of solar activities on earth environment

    Science.gov (United States)

    1975-01-01

    The effects of solar radiation on the near space and biomental earth, the upper atmosphere, and the magnetosphere are discussed. Data obtained from the OSO satellites pertaining to the solar cycle variation of extreme ultraviolet (EUV) radiation are analyzed. The effects of solar cycle variation of the characteristics of the solar wind are examined. The fluid mechanics of shock waves and the specific relationship to the characteristics of solar shock waves are investigated. The solar and corpuscular heating of the upper atmosphere is reported based on the findings of the AEROS and NATE experiments. Seasonal variations of the upper atmosphere composition are plotted based on OGO-6 mass spectrometer data.

  11. Multilayer front-sheet for solar modules with tuned color appearance

    NARCIS (Netherlands)

    Rooms, H.C.A.; Barbu, I.; Vroon, Z.A.E.P.; Meertens, R.; Vermeulen, B.

    2011-01-01

    The acceptance of solar cells in the built environment is partly dependent on the appearance of the solar modules. One aspect in the appearance is color. In most cases a solar cell itself reflects either blue or no color and will appear blackish. For the blue solar cells it is possible to tune the a

  12. Discrimination and quantification of contamination and implanted solar wind in Genesis collector shards using grazing incidence synchrotron x-ray techniques: Initial results

    International Nuclear Information System (INIS)

    Grazing incidence X-ray fluorescence is a non-destructive technique that can differentiate the embedded solar wind component from surface contamination and collector background in the Genesis shards. Initial solar Fe abundance in D30554 is 8 x 1012/cm2. Accurate knowledge of the composition of the Sun provides a baseline, which allows an understanding of how the solar system has evolved over time and how solar processes and solar wind mechanics behave. Unfortunately, the errors in photospheric abundances are too large for many planetary science problems and this hampers our understanding of these different processes. Analyses of solar wind implanted in meteorites or lunar soils have provided more precise data but alteration processes on these bodies may complicate such information. In response to this need for pristine solar wind samples, NASA developed and launched the Genesis Probe. Unfortunately, the probe smashed into the Utah desert shattering the 300 collector plates into 15,000+ pieces all of which are now coated in a both a fine terrestrial dust and Si and Ge powder from the disrupted collectors themselves. The solar wind penetration depth is 100-200 nm and the superposed contamination layers are typically 40-50 nm. Stringent cleaning regimes have the potential of removing the solar wind itself. The best solution is to have sufficient spatial resolution to separately analyze the surface contamination and penetrated solar wind. To that end, three Genesis collector array shards and their appropriate flight spares were characterized via grazing incidence x-ray fluorescence and x-ray reflectivity. The goals were (1) to evaluate the various cleaning methods used to eliminate contamination, (2) to identify the collector substrates most suited for this technique, (3) to determine whether the solar wind signature could be deconvolved from the collector background signature, and (4) to measure the relative abundances of Ca to Ge in the embedded solar wind.

  13. Improving the Performance of a Semitransparent BIPV by Using High-Reflectivity Heat Insulation Film

    Directory of Open Access Journals (Sweden)

    Huei-Mei Liu

    2016-01-01

    Full Text Available Currently, standard semitransparent photovoltaic (PV modules can largely replace architectural glass installed in the windows, skylights, and facade of a building. Their main features are power generation and transparency, as well as possessing a heat insulating effect. Through heat insulation solar glass (HISG encapsulation technology, this study improved the structure of a typical semitransparent PV module and explored the use of three types of high-reflectivity heat insulation films to form the HISG building-integrated photovoltaics (BIPV systems. Subsequently, the authors analyzed the influence of HISG structures on the optical, thermal, and power generation performance of the original semitransparent PV module and the degree to which enhanced performance is possible. The experimental results indicated that the heat insulation performance and power generation of HISGs were both improved. Selecting an appropriate heat insulation film so that a larger amount of reflective solar radiation is absorbed by the back side of the HISG can yield greater enhancement of power generation. The numerical results conducted in this study also indicated that HISG BIPV system not only provides the passive energy needed for power loading in a building, but also decreases the energy consumption of the HVAC system in subtropical and temperate regions.

  14. Performance of Three Reflectance Calibration Methods for Airborne Hyperspectral Spectrometer Data

    Directory of Open Access Journals (Sweden)

    Alfredo R. Huete

    2009-02-01

    Full Text Available In this study, the performances and accuracies of three methods for converting airborne hyperspectral spectrometer data to reflectance factors were characterized and compared. The “reflectance mode (RM” method, which calibrates a spectrometer against a white reference panel prior to mounting on an aircraft, resulted in spectral reflectance retrievals that were biased and distorted. The magnitudes of these bias errors and distortions varied significantly, depending on time of day and length of the flight campaign. The “linear-interpolation (LI” method, which converts airborne spectrometer data by taking a ratio of linearly-interpolated reference values from the preflight and postflight reference panel readings, resulted in precise, but inaccurate reflectance retrievals. These reflectance spectra were not distorted, but were subject to bias errors of varying magnitudes dependent on the flight duration length. The “continuous panel (CP” method uses a multi-band radiometer to obtain continuous measurements over a reference panel throughout the flight campaign, in order to adjust the magnitudes of the linear-interpolated reference values from the preflight and post-flight reference panel readings. Airborne hyperspectral reflectance retrievals obtained using this method were found to be the most accurate and reliable reflectance calibration method. The performances of the CP method in retrieving accurate reflectance factors were consistent throughout time of day and for various flight durations. Based on the dataset analyzed in this study, the uncertainty of the CP method has been estimated to be 0.0025 ± 0.0005 reflectance units for the wavelength regions not affected by atmospheric absorptions. The RM method can produce reasonable results only for a very short-term flight (e.g., < 15 minutes conducted around a local solar noon. The flight duration should be kept shorter than 30 minutes for the LI method to produce results with

  15. Evaluation of solar radiation abundance and electricity production capacity for application and development of solar energy

    OpenAIRE

    Mustamin Rahim, Jun Yoshino, Takashi Yasuda

    2012-01-01

    This study was undertaken to analyze solar radiation abundance to ascertain the potential of solar energy as an electrical energy resource. Local weather forecasting for predicting solar radiation is performed using a meteorological model MM5. The prediction results are compared with observed results obtained from the Japan Meteorological Agency for verification of the data accuracy. Results show that local weather forecasting has high accuracy. Prediction of solar radiation is similar with o...

  16. Development of paints with infrared radiation reflective properties

    Directory of Open Access Journals (Sweden)

    Eliane Coser

    2015-06-01

    Full Text Available AbstractLarge buildings situated in hot regions of the Globe need to be agreeable to their residents. Air conditioning is extensively used to make these buildings comfortable, with consequent energy consumption. Absorption of solar visible and infrared radiations are responsible for heating objects on the surface of the Earth, including houses and buildings. To avoid excessive energy consumption, it is possible to use coatings formulated with special pigments that are able to reflect the radiation in the near- infrared, NIR, spectrum. To evaluate this phenomenon an experimental study about the reflectivity of paints containing infrared-reflective pigments has been made. By irradiating with an IR source and by measuring the surface temperatures of the samples we evaluated: color according to ASTM D 2244-14, UV/VIS/NIR reflectance according to ASTM E 903-12 and thermal performance. Additionally, the spectral reflectance and the IR emittance were measured and the solar reflectance of the samples were calculated. The results showed that plates coated with paints containing IR-reflecting pigments displayed lower air temperature on the opposite side as compared to conventional coatings, indicating that they can be effective to reflect NIR and decrease the temperature of buildings when used in roofs and walls.

  17. Compact Microwave Fourier Spectrum Analyzer

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

    2009-01-01

    A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

  18. Serendipitous discovery of the faint solar twin Inti 1

    Science.gov (United States)

    Yana Galarza, Jhon; Meléndez, Jorge; Cohen, Judith G.

    2016-04-01

    Context. Solar twins are increasingly the subject of many studies owing to their wide range of applications from testing stellar evolution models to the calibration of fundamental observables; these stars are also of interest because high precision abundances could be achieved that are key to investigating the chemical anomalies imprinted by planet formation. Furthermore, the advent of photometric surveys with large telescopes motivates the identification of faint solar twins in order to set the zero point of fundamental calibrations. Aims: We intend to perform a detailed line-by-line differential analysis to verify whether 2MASS J23263267-0239363 (designated here as Inti 1) is indeed a solar twin. Methods: We determine the atmospheric parameters and differential abundances using high-resolution (R ≈ 50 000), high signal-to-noise (S/N ≈ 110-240 per pixel) Keck/HIRES spectra for our solar twin candidate, the previously known solar twin HD 45184, and the Sun (using reflected light from the asteroid Vesta). Results: For the bright solar twin HD 45184, we found Teff = 5864 ± 9 K, log g = 4.45 ± 0.03 dex, vt = 1.11 ± 0.02 km s-1, and [Fe/H] = 0.04 ± 0.01 dex, which are in good agreement with previous works. Our abundances are in excellent agreement with a recent high-precision work, with an element-to-element scatter of only 0.01 dex. The star Inti 1 has atmospheric parameters Teff = 5837 ± 11 K, log g = 4.42 ± 0.03 dex, vt = 1.04 ± 0.02 km s-1, and [Fe/H] = 0.07 ± 0.01 dex that are higher than solar. The age and mass of the solar twin HD 45184 (3 Gyr and 1.05 M⊙) and the faint solar twin Inti 1 (4 Gyr and 1.04 M⊙) were estimated using isochrones. The differential analysis shows that HD 45184 presents an abundance pattern that is similar to typical nearby solar twins; this means this star has an enhanced refractory relative to volatile elements, while Inti 1 has an abundance pattern closer to solar, albeit somewhat enhanced in refractories. The abundance

  19. Insights on the influence of surface roughness on photovoltaic properties of state of the art copper indium gallium diselenide thin films solar cells

    International Nuclear Information System (INIS)

    The influence of Cu(In,Ga)Se2 (CIGSe) surface roughness on the photovoltaic parameters of state of the art devices is reported, highlighting the importance of the roughness of the as-grown CIGSe absorbers on solar cell efficiencies. As-grown CIGSe surface is progressively smoothed using a chemical etch, and characterized by SEM, AFM, XPS, μ-Raman spectroscopy, x-ray diffraction (XRD), and reflectivity. The decrease of roughness has no marked influence on crystal structure and surface composition of the absorber. The main effect is that the total reflectivity of the CIGSe surface increases with decreasing roughness. The samples are processed into solar cells and characterized by current-voltage measurements. While the open circuit voltage (Voc) and fill factor remain constant, the short circuit current (Jsc) decreases markedly with decreasing roughness, resulting in a reduction of the solar cell efficiency from 14% down to 11%, which exceeds the expected decrease from increased reflectivity. Quantum efficiency and reflectivity measurements on complete cells are performed to analyze those effects. The influence of surface roughness on the theorical effective space charge region and diffusion length is based on a simple theoretical model. This paper discusses the comparison of CIGSe solar cells with n-i-p structures.

  20. Experimental analysis of a new retarding field energy analyzer

    International Nuclear Information System (INIS)

    In this paper, a new compact retarding field energy analyzer (RFEA) is designed for diagnosing electron beams of a K-band space travelling-wave tube (TWT). This analyzer has an aperture plate to sample electron beams and a cylindrical electrode to overcome the defocusing effects. The front end of the analyzer constructed as a multistage depression collector (MDC) structure is intended to shape the field to prevent electrons from being accelerated to escape. The direct-current (DC) beams of the K-band space TWTs with the removing MDC can be investigated on the beam measurement system. The current density distribution of DC beams is determined by the analyzer, while the anode voltage and helix voltage of the TWTs are 7000 V and 6850 V, respectively. The current curve’s slope effect due to the reflection of secondary electrons on the copper collector of the analyzer is discussed. The experimental analysis shows this RFEA has a good energy resolution to satisfy the requirement of beam measurement. - Highlights: • A new retarding field energy analyzer (RFEA) is designed to diagnose the electron beam of a K-band space TWT. • The current density distribution of direct-current beam is determined. • The reflection effect of secondary electrons on the copper collector of the analyzer is discussed

  1. Experimental analysis of a new retarding field energy analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yu-Xiang [Shanghai Institute of Mechanical and Electrical Engineering, No. 3888, Yuanjiang Road, Minhang District, Shanghai 201109 (China); Institute of Electronics, Chinese Academy of Sciences, No. 19, North 4th Ring Road West, Haidian District, Beijing 100190 (China); Liu, Shu-Qing; Li, Xian-Xia; Shen, Hong-Li; Huang, Ming-Guang [Institute of Electronics, Chinese Academy of Sciences, No. 19, North 4th Ring Road West, Haidian District, Beijing 100190 (China); Liu, Pu-Kun, E-mail: pkliu@pku.edu.cn [School of Electronics Engineering and Computer Science, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing 100871 (China)

    2015-06-11

    In this paper, a new compact retarding field energy analyzer (RFEA) is designed for diagnosing electron beams of a K-band space travelling-wave tube (TWT). This analyzer has an aperture plate to sample electron beams and a cylindrical electrode to overcome the defocusing effects. The front end of the analyzer constructed as a multistage depression collector (MDC) structure is intended to shape the field to prevent electrons from being accelerated to escape. The direct-current (DC) beams of the K-band space TWTs with the removing MDC can be investigated on the beam measurement system. The current density distribution of DC beams is determined by the analyzer, while the anode voltage and helix voltage of the TWTs are 7000 V and 6850 V, respectively. The current curve’s slope effect due to the reflection of secondary electrons on the copper collector of the analyzer is discussed. The experimental analysis shows this RFEA has a good energy resolution to satisfy the requirement of beam measurement. - Highlights: • A new retarding field energy analyzer (RFEA) is designed to diagnose the electron beam of a K-band space TWT. • The current density distribution of direct-current beam is determined. • The reflection effect of secondary electrons on the copper collector of the analyzer is discussed.

  2. Solar thermal

    International Nuclear Information System (INIS)

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m3 - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become increasingly important as fuel

  3. Thermal analysis of the main mirror in space solar telescope

    Science.gov (United States)

    Li, Rong; Shi, Hu-li; Chen, Zhi-yuan

    2007-12-01

    For the design of a space solar telescope (SST), the large reflect mirror faces to the sun directly, which is in an abominable thermal condition with seriously thermal distortion. In this paper, it sets up the thermal mode and analyzes the temperature field and thermal distortion of the main mirror of SST. Further more, it uses the thermal design software SINDA/G (System Improved Numerical Differencing Analyzer/Gaski) and the finite element analysis software MSC.Patran to set up different models and various temperature distributions of the main mirror. Though comparing with these models, the paraboloid mirror model is confirmed, which becomes a reference to later thermal analysis of the whole SST.

  4. Combined solar collector

    OpenAIRE

    Voznyak, O.; Shapoval, S.; Pona, O.; Vengryn, I.

    2014-01-01

    In this article was analyzing the efficiency of the combined solar collector for heating buildings. This enhances the efficiency of solar system by increasing the area of the absorption of solar energy. There are describes the results of the research on solar radiation input on a combined solar collector. Проаналізовано ефективність використання комбінованого сонячного колектора для теплопостачання будівель. Він забезпечує підвищення ефективності геліосистеми за рахунок збільшення площі погли...

  5. Technique for experimental determination of radiation interchange factors in solar wavelengths

    Science.gov (United States)

    Bobco, R. P.; Nolte, L. J.; Wensley, J. R.

    1971-01-01

    Process obtains solar heating data which support analytical design. Process yields quantitative information on local solar exposure of models which are geometrically and reflectively similar to prototypes under study. Models are tested in a shirtsleeve environment.

  6. A Framework for Teacher Reflectivity.

    Science.gov (United States)

    Stanley, Claire

    1998-01-01

    Proposes a framework for teacher reflection based on a longitudinal study of the development of six experienced second-language teachers who attempted to implement reflection and reflective action into their teaching practice. The resulting framework included several phases in the development of reflective teaching: engaging with reflection,…

  7. Hydrogen production from solar energy

    Science.gov (United States)

    Eisenstadt, M. M.; Cox, K. E.

    1975-01-01

    Three alternatives for hydrogen production from solar energy have been analyzed on both efficiency and economic grounds. The analysis shows that the alternative using solar energy followed by thermochemical decomposition of water to produce hydrogen is the optimum one. The other schemes considered were the direct conversion of solar energy to electricity by silicon cells and water electrolysis, and the use of solar energy to power a vapor cycle followed by electrical generation and electrolysis. The capital cost of hydrogen via the thermochemical alternative was estimated at $575/kW of hydrogen output or $3.15/million Btu. Although this cost appears high when compared with hydrogen from other primary energy sources or from fossil fuel, environmental and social costs which favor solar energy may prove this scheme feasible in the future.

  8. Facilitating management learning: Developing critical reflection through reflective tools

    OpenAIRE

    Gray, David E

    2007-01-01

    The aim of this article is to explore how the practice of critical reflection within a management learning process can be facilitated through the application of reflective processes and tools. A distinction is drawn between reflection as a form of individual development (of, say, the reflective practitioner), and critical reflection as a route to collective action and a component of organizational learning and change. Critical reflection, however, is not a process that comes naturally to many...

  9. Economical analysis of a solar desalination system

    DEFF Research Database (Denmark)

    Chen, Ziqian; Wang, Tie-Zhu; He, Xiao-Rong;

    2012-01-01

    and yearly electrical power, the life time of solar desalination unit and the yearly yield of fresh water, on the cost of the fresh water production of the solar desalination unit are studied. It is helpful to do the further investigation on solar desalination systems for reducing the cost of fresh water......Based on the calculation of the single-factor impact values of the parameters of a triple stage tower-type of solar desalination unit by utilizing a single-factor analyzing method, the influences of the cost of solar heating system, the cost of hot water tank, the costs of desalination unit...

  10. Theoretical Analysis of the Effect of a Bottom Reflector on a Vertical Multiple-Effect Diffusion Solar Still Coupled with a Basin-Type Still

    OpenAIRE

    Hiroshi Tanaka

    2013-01-01

    The effect of a flat plate bottom reflector on a vertical multiple-effect diffusion solar still coupled with a basin-type still is analyzed theoretically at 30°N latitude. The still has a right-angled triangular cross-section consisting of a horizontal basin liner, a sloping double glass cover, and the vertical multiple-effect diffusion still (multiple-effect section) at the vertical rear wall. A geometrical model was constructed to calculate the amount of solar radiation reflected by the ref...

  11. Solar Thermal Propulsion Test Facility

    Science.gov (United States)

    1999-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph shows a fully assembled solar thermal engine placed inside the vacuum chamber at the test facility prior to testing. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move theNation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  12. Influence of limited heliostat motion onto the efficiency of a solar field

    Science.gov (United States)

    Burisch, Michael; Mutuberria, Amaia; Olasolo, David; Villasante, Cristobal

    2016-05-01

    The efficiency of a central receiver solar thermal power plant depends on the ability of the heliostats to reflect the sunlight onto the receiver. Reflecting the sunlight over the course of a year requires the drive system to move the heliostat over a wide range of azimuth and elevation angles, which results to be a challenge in the development of new low cost drive system designs. Reducing this range simplifies the design and would, therefore, enable further cost savings. At the same time, reducing the range would also cause efficiency losses of the solar field, as the heliostats would not be able to reflect the sunlight under all conditions. Analyzing the range of motions required for each heliostat and the flux contribution of each position allows assessing these losses. With the aim of minimizing the losses an optimal range of heliostat motions can be chosen. It is shown that in combination with properly placing each heliostat in the solar field, the efficiency losses due to the limited motion range can be kept low as most of the receiver incident flux results from a small range of heliostat orientations. If such a heliostat design allow for sufficiently high costs saving per heliostat the potential losses can be compensated by adding more heliostats to the field, while still reducing the overall expenses.

  13. Solar Energy Collection and Management for Networked Infomechanical Systems (NIMS)

    OpenAIRE

    Rachel Scollans; Lisa Shirachi; Kris Porter; Richard Pon; Ashutosh Verma; Winston Wu; William Kaiser

    2003-01-01

    Method: the experimentation tested various properties under different conditions to characterize the solar cells. Results: established the amount of power the solar array could harvest in a day. Some effects of shading and complete coverage on the solar panel were factored and evaluated. The effects of weather on the solar system were found and analyzed. Conclusions: the battery bank needs a minimum of three days of storage (for short-term deployment) more is optimal. The solar panels should ...

  14. Biology Reflective Assessment Curriculum

    Science.gov (United States)

    Bayley, Cheryl Ann

    Often students and educators view assessments as an obligation and finality for a unit. In the current climate of high-stakes testing and accountability, the balance of time, resources and emphasis on students' scores related to assessment have been slanted considerably toward the summative side. This tension between assessment for accountability and assessment to inform teaching strains instruction and educators' ability to use that information to design learning opportunities that help students develop deeper conceptual understanding. A substantive body of research indicates that formative and reflective assessment can significantly improve student learning. Biology Reflective Assessment Curriculum (BRAC) examines support provided for high school science students through assessment practices. This investigation incorporates the usage of reflective assessments as a guiding practice for differentiated instruction and student choice. Reflective assessment is a metacognitive strategy that promotes self-monitoring and evaluation. The goals of the curriculum are to promote self-efficacy and conceptual understanding in students learning biology through developing their metacognitive awareness. BRAC was implemented in a high school biology classroom. Data from assessments, metacognitive surveys, self-efficacy surveys, reflective journals, student work, a culminating task and field notes were used to evaluate the effectiveness of the curriculum. The results suggest that students who develop their metacognitive skills developed a deeper conceptual understanding and improved feelings of self-efficacy when they were engaged in a reflective assessment unit embedded with student choice. BRAC is a tool for teachers to use assessments to assist students in becoming metacognitive and to guide student choice in learning opportunities.

  15. Reinventing the Solar Power Satellite

    Science.gov (United States)

    Landis, Geoffrey A.

    2004-01-01

    The selling price of electrical power varies with time. The economic viability of space solar power is maximum if the power can be sold at peak power rates, instead of baseline rate. Price and demand of electricity was examined from spot-market data from four example markets: New England, New York City, suburban New York, and California. The data was averaged to show the average price and demand for power as a function of time of day and time of year. Demand varies roughly by a factor of two between the early-morning minimum demand, and the afternoon maximum; both the amount of peak power, and the location of the peak, depends significantly on the location and the weather. The demand curves were compared to the availability curves for solar energy and for tracking and non-tracking satellite solar power systems in order to compare the market value of terrestrial and solar electrical power. In part 2, new designs for a space solar power (SSP) system were analyzed to provide electrical power to Earth for economically competitive rates. The approach was to look at innovative power architectures to more practical approaches to space solar power. A significant barrier is the initial investment required before the first power is returned. Three new concepts for solar power satellites were invented and analyzed: a solar power satellite in the Earth-Sun L2 point, a geosynchronous no-moving parts solar power satellite, and a nontracking geosynchronous solar power satellite with integral phased array. The integral-array satellite had several advantages, including an initial investment cost approximately eight times lower than the conventional design.

  16. Planar solar reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Chiam, M.F.

    1982-10-01

    A planar reflector is preferred to curved alternatives as a concentrating or augmenting device for a flat plate solar collector. The performance characteristics of a reflector-augmented collector have previously been determined, and are reviewed in this paper. Particular emphasis is placed on the practical application of the principal results to single reflector and V-trough systems. The usefulness of highly reflective, horizontal diffuse surface to a tilted collector, and the comparative performance of a faceted reflector containing two planar segments are also discussed.

  17. Focused crossed Andreev reflection

    Science.gov (United States)

    Haugen, H.; Brataas, A.; Waintal, X.; Bauer, G. E. W.

    2011-03-01

    We consider non-local transport mediated by Andreev reflection in a two-dimensional electron gas (2DEG) connected to one superconducting and two normal metal terminals. A robust scheme is presented for observing crossed Andreev reflection (CAR) between the normal metal terminals based on electron focusing by weak perpendicular magnetic fields. At slightly elevated temperatures the CAR signature can be easily distinguished from a background of quantum interference fluctuations. The CAR-induced entanglement between electrons can be switched on and off over large distances by the magnetic field.

  18. Reflection from black holes

    CERN Document Server

    Kuchiev, M Yu

    2003-01-01

    Black holes are presumed to have an ideal ability to absorb and keep matter. Whatever comes close to the event horizon, a boundary separating the inside region of a black hole from the outside world, inevitably goes in and remains inside forever. This work shows, however, that quantum corrections make possible a surprising process, reflection: a particle can bounce back from the event horizon. For low energy particles this process is efficient, black holes behave not as holes, but as mirrors, which changes our perception of their physical nature. Possible ways for observations of the reflection and its relation to the Hawking radiation process are outlined.

  19. Postscript: Delving into Reflection

    Directory of Open Access Journals (Sweden)

    Susan Noffke

    2005-09-01

    Full Text Available Although, the authors presented an earlier version of the paper, "The Dimensions of Reflection: A Conceptual and Contextual Analysis", at the Annual Meeting of the American Educational Research Association, New Orleans, April, 1988, they did not have a chance to publish the paper till today. This postscript is about why the paper stayed as an “unpublished” conference paper for so long. Editors believe that the authors’ reflection on their academic journey with the paper in the postscript could be seen as an outstanding practical exemplar, a moral-political narrative of how to shape and create well-formed academic lives and identities.

  20. Analyzing and modeling heterogeneous behavior

    Science.gov (United States)

    Lin, Zhiting; Wu, Xiaoqing; He, Dongyue; Zhu, Qiang; Ni, Jixiang

    2016-05-01

    Recently, it was pointed out that the non-Poisson statistics with heavy tail existed in many scenarios of human behaviors. But most of these studies claimed that power-law characterized diverse aspects of human mobility patterns. In this paper, we suggest that human behavior may not be driven by identical mechanisms and can be modeled as a Semi-Markov Modulated Process. To verify our suggestion and model, we analyzed a total of 1,619,934 records of library visitations (including undergraduate and graduate students). It is found that the distribution of visitation intervals is well fitted with three sections of lines instead of the traditional power law distribution in log-log scale. The results confirm that some human behaviors cannot be simply expressed as power law or any other simple functions. At the same time, we divided the data into groups and extracted period bursty events. Through careful analysis in different groups, we drew a conclusion that aggregate behavior might be composed of heterogeneous behaviors, and even the behaviors of the same type tended to be different in different period. The aggregate behavior is supposed to be formed by "heterogeneous groups". We performed a series of experiments. Simulation results showed that we just needed to set up two states Semi-Markov Modulated Process to construct proper representation of heterogeneous behavior.

  1. Los Alamos Nuclear plant analyzer

    International Nuclear Information System (INIS)

    The Relational Database software obtained from Idaho National Engineering Laboratory is implemented on the Los Alamos Cray computer system. For the Nuclear Plant Analyzer (NPA), Los Alamos retained a graphics display terminal and a separate forms terminal for mutual compatibility, but integrated both the terminals into a single-line full-duplex mode of communications, using a single keyboard for input. Work on the program-selection phase of an NPA session is well underway. The final phase of implementation will be the Worker or graphics-driver phase. The Los Alamos in-house NPA has been in use for some time, and has given good results in analyses of four transients. The NPA hydrocode has been developed in to a fast-running code. The authors have observed an average of a factor-of-3 speed increase for typical slow reactor-safety transients when employing the stability enhancing two-step (SETS) method in the one-dimensional components using PF1/MOD1. The SETS method allows violation of the material Courant time-step stability limit and is thus stable at large time steps. The SETS method to the three-dimensional VESSEL component in the NPA hydrocode has been adapted. In addition to the speed increase from this new software, significant additional speed is expected as a result of new hardware that provides for vectorization or parallelization

  2. Integral representation of Skorokhod reflection

    OpenAIRE

    Anantharam, Venkat; Konstantopoulos, Takis

    2010-01-01

    We show that a certain integral representation of the one-sided Skorokhod reflection of a continuous bounded variation function characterizes the reflection in that it possesses a unique maximal solution which solves the Skorokhod reflection problem.

  3. High-Reflectance Technology on Building Façades: Installation Guidelines for Pedestrian Comfort

    Directory of Open Access Journals (Sweden)

    Hideki Takebayashi

    2016-08-01

    Full Text Available The focus of this study is on the impact of solar radiation reflected from the building façade to a pedestrian. The possibility of using high-reflectance technology on building façades was evaluated by using a two-dimensional simple building façade model. The effectiveness of applying retroreflective materials to building façades was also evaluated in regards to avoiding adverse effects on pedestrians. The ratio of diffusely-reflected solar radiation to a pedestrian from a given floor is proportional to the ratio of the angle of the reflective arc reaching a pedestrian from that floor to the angle of the reflective arc from the entire building. Specular reflection of solar radiation from the building façade is calculated by ray-tracing method corresponding to solar angle θ. In Japanese cities that are located at mid-latitudes, applying high-reflectance technology to a building façade at the fourth floor and above produces reflection of solar radiation that does not have adverse effects on pedestrians. High-reflectance technology is applicable on building façades above the fourth floor at any latitude, if we ignore a negative effect, since incident direct solar radiation to the building façade around noon is small at low latitude. Retroreflective material was considered for use on building façades below the third floor in order to avoid impacts on pedestrians from the reflection of solar radiation.

  4. A calibration free vector network analyzer

    Science.gov (United States)

    Kothari, Arpit

    Recently, two novel single-port, phase-shifter based vector network analyzer (VNA) systems were developed and tested at X-band (8.2--12.4 GHz) and Ka-band (26.4--40 GHz), respectively. These systems operate based on electronically moving the standing wave pattern, set up in a waveguide, over a Schottky detector and sample the standing wave voltage for several phase shift values. Once this system is fully characterized, all parameters in the system become known and hence theoretically, no other correction (or calibration) should be required to obtain the reflection coefficient, (Gamma), of an unknown load. This makes this type of VNA "calibration free" which is a significant advantage over other types of VNAs. To this end, a VNA system, based on this design methodology, was developed at X-band using several design improvements (compared to the previous designs) with the aim of demonstrating this "calibration-free" feature. It was found that when a commercial VNA (HP8510C) is used as the source and the detector, the system works as expected. However, when a detector is used (Schottky diode, log detector, etc.), obtaining correct Gamma still requires the customary three-load calibration. With the aim of exploring the cause, a detailed sensitivity analysis of prominent error sources was performed. Extensive measurements were done with different detection techniques including use of a spectrum analyzer as power detector. The system was tested even for electromagnetic compatibility (EMC) which may have contributed to this issue. Although desired results could not be obtained using the proposed standing-wave-power measuring devices like the Schottky diode but the principle of "calibration-free VNA" was shown to be true.

  5. Reflectance measurements from particulate surfaces

    Science.gov (United States)

    Peltoniemi, J.; Gritsevich, M.; Hakala, T.; Penttilä, A.; Eskelinen, J.; Dagsson-Waldhauserova, P.; Arnalds, O.; Guirado, D.; Muinonen, K.

    2014-07-01

    Asteroids consists of, e.g., metals and rocky materials, and comets consist of, e.g., icy and rocky materials and dust. Their surfaces can be covered by small particles. To certain extent, these surfaces can resemble some natural or artificial surfaces on the Earth, such as snow layers, sand, gravels, or silt. By measuring the reflectance from such surfaces, one can gain better understanding on how to interpret astronomical observations of asteroids and comets. Even if not completely analogous, these samples and measurements provide a strict test bed for the scattering models applied to interpret observations of small Solar System bodies. FIGIFIGO (Finnish Geodetic Institute's Field Gonio-spectro-polari- radiometer) can measure the bidirectional reflectance factor (BRF) of surface targets of a diameter of around 10 cm, in a selected angular range and resolution, in the spectral range of 400-2400 nm, at about 10-nm resolution, including linear polarisation (Stokes I, Q, and U, or reflection coefficient matrix elements R_{11}, R_{12}, and R_{13}). Using FIGIFIGO, over 500 samples have been measured over the past years, including over 100 snow samples and almost 100 samples resembling sand, silt, soil, dust, or gravel. For planetary studies, especially interesting are dark volcanic ash and silt samples from Eyjafjallajökull and Grímsvönt eruptions. These have been measured loose and compressed, smooth and rough, purely and deposited on snow. Further single-scattering measurements using the Granada setup and measurements using the Univ. Helsinki integrating sphere complement the picture. Generally, we have observed that the reflectance from volcanic materials behaves mostly as expected and modelled. BRF shows typical bowl shape with strong phase-angle dependence. Spectral features are smooth, with slight angular dependence. Polarisation depends strongly on the phase angle, weaker on other angles defining the scattering geometry, and smoothly on the wavelength. There

  6. Reflection in learning at work

    DEFF Research Database (Denmark)

    Pedersen, Steen Høyrup

    2006-01-01

    Three domains and approaches of learning - adult learning, problem-solving and cirtical reflection theory are used as different lenses through which the question: what is reflection and how is reflection related to learning, - are interpreted.......Three domains and approaches of learning - adult learning, problem-solving and cirtical reflection theory are used as different lenses through which the question: what is reflection and how is reflection related to learning, - are interpreted....

  7. Variability of Photovoltaic Power in the State of Gujarat Using High Resolution Solar Data

    Energy Technology Data Exchange (ETDEWEB)

    Hummon, M.; Cochran, J.; Weekley, A.; Lopez, A.; Zhang, J.; Stoltenberg, B.; Parsons, B.; Batra, P.; Mehta, B.; Patel, D.

    2014-03-01

    India has ambitious goals for high utilization of variable renewable power from wind and solar, and deployment has been proceeding at a rapid pace. The western state of Gujarat currently has the largest amount of solar generation of any Indian state, with over 855 Megawatts direct current (MWDC). Combined with over 3,240 MW of wind, variable generation renewables comprise nearly 18% of the electric-generating capacity in the state. A new historic 10-kilometer (km) gridded solar radiation data set capturing hourly insolation values for 2002-2011 is available for India. We apply an established method for downscaling hourly irradiance data to one-minute irradiance data at potential PV power production locations for one year, 2006. The objective of this report is to characterize the intra-hour variability of existing and planned photovoltaic solar power generation in the state of Gujarat (a total of 1.9 gigawatts direct current (GWDC)), and of five possible expansion scenarios of solar generation that reflect a range of geographic diversity (each scenario totals 500-1,000 MW of additional solar capacity). The report statistically analyzes one year's worth of power variability data, applied to both the baseline and expansion scenarios, to evaluate diurnal and seasonal power fluctuations, different timescales of variability (e.g., from one to 15 minutes), the magnitude of variability (both total megawatts and relative to installed solar capacity), and the extent to which the variability can be anticipated in advance. The paper also examines how Gujarat Energy Transmission Corporation (GETCO) and the Gujarat State Load Dispatch Centre (SLDC) could make use of the solar variability profiles in grid operations and planning.

  8. Variability of Power from Large-Scale Solar Photovoltaic Scenarios in the State of Gujarat: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, B.; Hummon, M.; Cochran, J.; Stoltenberg, B.; Batra, P.; Mehta, B.; Patel, D.

    2014-04-01

    India has ambitious goals for high utilization of variable renewable power from wind and solar, and deployment has been proceeding at a rapid pace. The western state of Gujarat currently has the largest amount of solar generation of any Indian state, with over 855 Megawatts direct current (MWDC). Combined with over 3,240 MW of wind, variable generation renewables comprise nearly 18% of the electric-generating capacity in the state. A new historic 10-kilometer (km) gridded solar radiation data set capturing hourly insolation values for 2002-2011 is available for India. We apply an established method for downscaling hourly irradiance data to one-minute irradiance data at potential PV power production locations for one year, 2006. The objective of this report is to characterize the intra-hour variability of existing and planned photovoltaic solar power generation in the state of Gujarat (a total of 1.9 gigawatts direct current (GWDC)), and of five possible expansion scenarios of solar generation that reflect a range of geographic diversity (each scenario totals 500-1,000 MW of additional solar capacity). The report statistically analyzes one year's worth of power variability data, applied to both the baseline and expansion scenarios, to evaluate diurnal and seasonal power fluctuations, different timescales of variability (e.g., from one to 15 minutes), the magnitude of variability (both total megawatts and relative to installed solar capacity), and the extent to which the variability can be anticipated in advance. The paper also examines how Gujarat Energy Transmission Corporation (GETCO) and the Gujarat State Load Dispatch Centre (SLDC) could make use of the solar variability profiles in grid operations and planning.

  9. A Novel Concentrator Photovoltaic (CPV System with the Improvement of Irradiance Uniformity and the Capturing of Diffuse Solar Radiation

    Directory of Open Access Journals (Sweden)

    Nguyen Xuan Tien

    2016-09-01

    Full Text Available This paper proposes a novel concentrator photovoltaic (CPV system with improved irradiation uniformity and system efficiency. CPV technology is very promising its for highly efficient solar energy conversion. A conventional CPV system usually uses only one optical component, such as a refractive Fresnel lens or a reflective parabolic dish, to collect and concentrate solar radiation on the solar cell surface. Such a system creates strongly non-uniform irradiation distribution on the solar cell, which tends to cause hot spots, current mismatch, and degrades the overall efficiency of the system. Additionally, a high-concentration CPV system is unable to collect diffuse solar radiation. In this paper, we propose a novel CPV system with improved irradiation uniformity and collection of diffuse solar radiation. The proposed system uses a Fresnel lens as a primary optical element (POE to concentrate and focus the sunlight and a plano-concave lens as a secondary optical element (SOE to uniformly distribute the sunlight over the surface of multi-junction (MJ solar cells. By using the SOE, the irradiance uniformity is significantly improved in the system. Additionally, the proposed system also captures diffuse solar radiation by using an additional low-cost solar cell surrounding MJ cells. In our system, incident direct solar radiation is captured by MJ solar cells, whereas incident diffuse solar radiation is captured by the low-cost solar cell. Simulation models were developed using a commercial optical simulation tool (LightTools™. The irradiance uniformity and efficiency of the proposed CPV system were analyzed, evaluated, and compared with those of conventional CPV systems. The analyzed and simulated results show that the CPV system significantly improves the irradiance uniformity as well as the system efficiency compared to the conventional CPV systems. Numerically, for our simulation models, the designed CPV with the SOE and low-cost cell provided

  10. Punctum: Reflections on Photography

    OpenAIRE

    Fusco, Maria

    2014-01-01

    Group show for which I was invited to contribute one photograph to the exhibition Punctum. Consisting of fifty photographs and artworks chosen by artists, curators and writers, curated by Séamus Kealy, Punctum takes its cue from the term “punctum” coined by Roland Barthes in his final book Camera Lucida: Reflections on Photography.

  11. The Reflective Methodologists

    DEFF Research Database (Denmark)

    Kjær, Bjørg

    2013-01-01

    in which the practical sense and tacit knowledge are related to questions of power and social actors’ strategies for positioning themselves within a social space. This demands a particular focus on the historical effect of the concept of ‘the reflective practitioner’ as a symbolic marker of identity...

  12. Reflection by Porro Prisms

    Science.gov (United States)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  13. Reflecting on Data

    Science.gov (United States)

    Kraus, Rudolf V.

    2014-01-01

    This article describes a two-day optics laboratory activity that investigates the scientific phenomenon of reflection, which students are generally familiar with but usually have not studied in depth. This investigation can be used on its own or as part of a larger unit on optics. This lesson encourages students to think critically and…

  14. Changes Brought by Reflection

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Feng: A number of changes have taken place in Europe after reflection, such as specific anti-terrorist measures, progress in the construction of integration, changes in the structure of political forces and adjustments in the EU foreign policy. Would you make some comments first, Dr. Sun?

  15. Lights, Camera, Reflection!

    Science.gov (United States)

    Mourlam, Daniel

    2013-01-01

    There are many ways to critique teaching, but few are more effective than video. Personal reflection through the use of video allows one to see what really happens in the classrooms--good and bad--and provides a visual path forward for improvement, whether it be in one's teaching, work with a particular student, or learning environment. This…

  16. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...

  17. The HERMES Solar Atlas and the spectroscopic analysis of the seismic solar analogue KIC3241581

    CERN Document Server

    Beck, P G; Van Reeth, T; Tkachenko, A; Raskin, G; van Winckel, H; Nascimento, J -D do; Salabert, D; Corsaro, E; Garcia, R A

    2015-01-01

    Solar-analog stars provide an excellent opportunity to study the Sun's evolution, i.e. the changes with time in stellar structure, activity, or rotation for solar-like stars. The unparalleled photometric data from the NASA space telescope Kepler allows us to study and characterise solar-like stars through asteroseismology. We aim to spectroscopically investigate the fundamental parameter and chromospheric activity of solar analogues and twins, based on observations obtained with the HERMES spectrograph and combine them with asteroseismology. Therefore, we need to build a solar atlas for the spectrograph, to provide accurate calibrations of the spectroscopically determined abundances of solar and late type stars observed with this instrument and thus perform differential spectral comparisons. We acquire high-resolution and high signal-to-noise spectroscopy to construct three solar reference spectra by observing the reflected light of Vesta and Victoria asteroids and Europa (100

  18. Introduction to solar heating and cooling design and sizing

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-01

    This manual is designed to introduce the practical aspects of solar heating/cooling systems to HVAC contractors, architects, engineers, and other interested individuals. It is intended to enable readers to assess potential solar heating/cooling applications in specific geographical areas, and includes tools necessary to do a preliminary design of the system and to analyze its economic benefits. The following are included: the case for solar energy; solar radiation and weather; passive solar design; system characteristics and selection; component performance criteria; determining solar system thermal performance and economic feasibility; requirements, availability, and applications of solar heating systems; and sources of additional information. (MHR)

  19. Assessment of solar-powered cooling of buildings. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Curran, H.M.

    1975-04-01

    Three solar-powered cooling concepts are analyzed and evaluated. These are: (1) the solar Rankine concept in which a Rankine cycle driven by solar energy is used to drive a vapor compression refrigeration machine, (2) the solar-assisted Rankine concept in which a Rankine cycle driven by both solar energy and fuel combustion is used to drive a vapor compression refrigeration machine, and (3) the solar absorption concept in which solar energy is used to drive an absorption refrigeration machine. These concepts are compared on the bases of coefficient of performance, requirements for primary fuel input, and economic considerations. Conclusions and recommendations are presented. (WHK)

  20. Analyzing Sulfur Dioxide Emissions of Nyamuragira Volcano

    Science.gov (United States)

    Guth, A. L.; Bluth, G. J.; Carn, S. A.

    2002-05-01

    Nyamuragira volcano, located in the Democratic Republic of Congo, is Africa's most active volcano, having erupted 13 times (every 1-3 years) since 1980. The eruption frequency, and the large amounts of sulfur dioxide emitted by this rift volcano, may produce a significant impact on the global sulfur budget. In this project we are attempting to quantify the sulfur dioxide emissions from this volcano over the past 20+ years using satellite data. Since 1978, satellites carrying NASA's Total Ozone Mapping Spectrometer (TOMS) instruments have been orbiting the earth collecting atmospheric data. These instruments use six wavelength bands located within the ultraviolet spectrum to measure solar irradiance and the energy reflected and backscattered by the Earth's surface and atmosphere. Sunlit planetary coverage is provided once per day by TOMS data. The spatial resolution of these satellites varies from 24 km (Earth Probe, 1996-1997, but raised to 39 km from 1997 to present) to 62 km (Meteor-3, 1991-1994). Nimbus-7, the satellite operating for the longest span of time (1978-1993), had a nadir footprint of 50 km. The (instantaneous) mass retrievals of sulfur dioxide cloud masses are derived using several different image processing schemes and net tonnages are calculated using a background correction. Volcanic activity associated with this volcano typically consists of long term (weeks to months), and often continuous, effusive emissions. Work to date has discovered over 120 days in which sulfur dioxide plumes were observed from the 13 eruptions (ranging from a minimum of one day to a maximum of 32 days). Most (82%) of the sulfur dioxide clouds measured are relatively low-level, below 100 kilotonnes (kt); 16% of the emissions are between 100 and 1000 kt, and 1.5% were measured to have more than 1000 kt. Current work is focusing on deriving net emission fluxes, integrating the TOMS instantaneous measurements of relatively continuous emission activity. The eruptive activity

  1. Performance analysis of conventional and sloped solar chimney power plants in China

    International Nuclear Information System (INIS)

    The solar chimney power plant (SCPP) has been accepted as one of the most promising approaches for future large-scale solar energy applications. This paper reports on a heat transfer model that is used to compare the performance of a conventional solar chimney power plant (CSCPP) and two sloped solar chimney power plants (SSCPPs) with the collector oriented at 30° and 60°, respectively. The power generation from SCPPs at different latitudes in China is also analyzed. Results indicate that the larger solar collector angle leads to improved performance in winter but results in lower performance in summer. It is found that the optimal collector angle to achieve the maximum power in Lanzhou, China, is around 60°. Main factors that influence the performance of SCPPs also include the system height and the air thermophysical characteristics. The ground energy loss, reflected solar radiation, and kinetic loss at the chimney outlet are the main energy losses in SCPPs. The studies also show SSCPPs are more suitable for high latitude regions in Northwest China, but CSCPPs are suggested to be built in southeastern and eastern parts of China with the combination to the local agriculture. - Highlights: ► The optimum collector angle for maximum power generation is 60° in Lanzhou. ► Main parameters influencing performances are the system height and air property. ► Ground loss, reflected loss and outlet kinetic loss are the main energy losses. ► The sloped styles are suitable for Northwest China. ► The conventional styles are suitable for Southeast and East China.

  2. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  3. Solar prominences

    CERN Document Server

    Engvold, Oddbjørn

    2015-01-01

    This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

  4. Solar Lentigo

    Science.gov (United States)

    ... your body. Treatments Your Physician May Prescribe If solar lentigines are cosmetically bothersome, your physician may: Freeze the area lightly with liquid nitrogen. Prescribe a bleaching cream (hydroquinone), but this is often not successful. Trusted ...

  5. Solar chulha

    Science.gov (United States)

    Jadhao, P. H.; Patrikar, S. R.

    2016-05-01

    The main goal of the proposed system is to transfer energy from sun to the cooking load that is located in the kitchen. The energy is first collected by the solar collector lens system and two curve bars of same radius of curvature are mounted parallel and adjacent to each other at different height the solar collector is clamed on this two bars such that solar collector is exactly perpendicular to sunlight. The topology includes an additional feature which is window in the wall through which the beam is collimated is directed in the of kitchen. The solar energy that is collected is directed by the mirror system into the kitchen, where it is redirected to cooking platform located in the kitchen. The special feature in this system full Indian meal can be made since cooking platform is indoors.

  6. Optimization of spectrally-selective coatings for solar absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Orel, Z.C.; Gunde, M.K. [National Inst. of Chemistry, Ljubljana (Slovenia)

    2000-07-01

    The inexpensive selective surfaces for solar absorbers were prepared by application of black paint on the high-reflective substrate. The layers have to be transparent in the infrared in order to support the low thermal emittance of the substrate. For this purpose, the optical properties of coatings have to be optimized to minimize the expense of the final product. The selectivity was attained by the mutual effect of a highly absorptive black paint layer and low emitting (i.e., infrared reflecting) metal substrate. Optimized paint coatings are not thicker than a few micrometers and exhibit high opacity, leading to energy-efficient selective coatings for solar collector applications. The painted samples are characterized by high absorption, finite sample thickness, nonideal support material, and smooth front surface. These properties distinguish our samples from those of other studies in this field. To design a functional pigmented layer, the optical properties of all constituents have to be known separately. Due to this reason the diffuse reflectance of black thickness-sensitive spectrally selective (TSSS) paints was analyzed. For theoretical consideration of paint layers, the simple Kubelka-Munk (KM) theory was used. It is the almost universally applied theoretical approach within the color using industry (1). It relates diffuse reflectance of a pigmented layer to two phenomenological coefficients, absorption (K) and scattering (S), thickness of the layer, and reflectance of the substrate. The optical properties of layer material are involved in both coefficients. This enables optimal thickness calculation (2), i.e. the theoretical prediction of the best thickness value that will give the highest solar absorptance and simultaneously, the lowest thermal emittance of the respective paint. The KM coefficients depend also upon addition of fumed silica (dispersive agent). Applying KM theory, the degree of pigment dispersion was quantified (3). This approach was an

  7. Measuring Practicum Student Teachers' Reflectivity: The Reflective Pedagogical Thinking Scale

    Science.gov (United States)

    Seng, Toh Wah

    2004-01-01

    The purpose of the original study was to investigate practicum student teachers' reflectivity. This paper describes the use of a revised version of the Reflective Pedagogical Thinking Scale (Sparks-Langer, et al., 1990) to measure reflectivity. The original scale was used by the developers to assess reflectivity through a structured interview. The…

  8. Being a reflective teacher——reflection on group management

    Institute of Scientific and Technical Information of China (English)

    Pan; Lehui

    2015-01-01

    <正>Introduction According to Pollard and Triggs(1997),reflective teaching is a process through which the capacity to make such professional judgments can be developed and maintained.Then what is a reflective teacher?Reflective teacher is someone who reflects systematically on her practice in a constant attempt to improve

  9. Characterizations of the mirror attenuator mosaic - Solar diffuser plate

    Science.gov (United States)

    Lee, Robert B., III; Avis, Lee M.; Gibson, M. A.; Kopia, Leonard P.

    1992-01-01

    The mirror attenuator mosaic (MAM), a solar diffuser plate, was used for the flight calibration of the broadband shortwave (0.2-5-microns) and total (0.2 to greater than 200-microns) Earth Radiation Budget Experiment scanning thermistor bolometer radiometers. The MAM solar-reflecting surface consisted of a tightly packed array of vacuum-deposited aluminum, concave spherical mirrors, while its solar-absorbing surface consisted of black chrome. The effective reflectance of the MAM was constant to within +/- 2 percent after almost 2 years in orbit, a marked improvement over earlier solar diffusers.

  10. X-ray reflection in oxygen-rich accretion discs of ultracompact X-ray binaries

    DEFF Research Database (Denmark)

    Madej, O. K.; Garcia, Jeronimo; Jonker, P. G.;

    2014-01-01

    donor star in these sources is a carbon-oxygen or oxygen-neon-magnesium white dwarf. Hence, the accretion disc is enriched with oxygen which makes the O viii Ly alpha line particularly strong. Modelling the X-ray reflection off a carbon- and oxygen-enriched, hydrogen- and helium-poor disc with models...... assuming solar composition likely biases several of the best-fitting parameters. In order to describe the X-ray reflection spectra self-consistently, we modify the currently available xillver reflection model. We present initial grids that can be used to model X-ray reflection spectra in UCXBs with carbon-oxygen......-rich (and hydrogen- and helium-poor) accretion disc. We find that the new reflection model provides a better overall description of the reflection spectra of 4U 0614+091 and 4U 1543-624 than the reflection models that assume solar abundances....

  11. Highly reflective polymeric substrates functionalized utilizing atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zuzuarregui, Ana, E-mail: a.zuzuarregui@nanogune.eu; Gregorczyk, Keith E. [CIC Nanogune Consolider, de Tolosa Hiribidea 76, 20018 San Sebastián (Spain); Coto, Borja; Ruiz de Gopegui, Unai; Barriga, Javier [IK4-Tekniker, Iñaki Goenaga 5, 20600 Eibar (Spain); Rodríguez, Jorge [Torresol Energy (SENER Group), Avda. de Zugazarte 61, 48930 Las Arenas (Spain); Knez, Mato [CIC Nanogune Consolider, de Tolosa Hiribidea 76, 20018 San Sebastián (Spain); IKERBASQUE Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao (Spain)

    2015-08-10

    Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur.

  12. Highly reflective polymeric substrates functionalized utilizing atomic layer deposition

    International Nuclear Information System (INIS)

    Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur

  13. Design principle for absorption enhancement with nanoparticles in thin-film silicon solar cells

    International Nuclear Information System (INIS)

    The use of nanoparticles in solar cells has created many controversies. In this paper, different mechanisms of nanoparticles with different materials with diameters varying from 50 to 200 nm, surface coverage at 5, 20, and 60 %, and different locations are analyzed systematically for efficient light trapping in a thin-film c-Si solar cell. Mie theory and the finite difference time domain method are used for analysis to give a design principle with nanoparticles for the solar cell application. Metals exhibit plasmonic resonances and angular scattering, while dielectrics show anti-reflection and scattering in the incident direction. A table is given to summarize the advantages and disadvantages in different conditions. The silicon absorption enhancement with nanoparticles on top is mainly in the shorter wavelengths below 700 nm, and both Al and SiO2 nanoparticles with diameter around 100 nm show the most significant enhancement. The silicon absorption enhancement with embedded nanoparticles takes place in the longer wavelengths over 700 nm, and Ag and SiO2 nanoparticles with larger diameter around 200 nm perform better. However, the light absorbed by Ag nanoparticles will be converted to heat and will lead to decrease in cell efficiency; hence, the choice of metallic nanoparticles in applications to solar cells should be carefully considered. The design principle proposed in this work gives a guideline by choosing reasonable parameters for the different requirements in the application of thin-film solar cells

  14. Indoor Light Performance of Coil Type Cylindrical Dye Sensitized Solar Cells.

    Science.gov (United States)

    Kapil, Gaurav; Ogomi, Yuhei; Pandey, Shyam S; Ma, Tingli; Hayase, Shuzi

    2016-04-01

    A very good performance under low/diffused light intensities is one of the application areas in which dye-sensitized solar cells (DSSCs) can be utilized effectively compared to their inorganic silicon solar cell counterparts. In this article, we have investigated the 1 SUN and low intensity fluorescent light performance of Titanium (Ti)-coil based cylindrical DSSC (C-DSSC) using ruthenium based N719 dye and organic dyes such as D205 and Y123. Electrochemical impedance spectroscopic results were analyzed for variable solar cell performances. Reflecting mirror with parabolic geometry as concentrator was also utilized to tap diffused light for indoor applications. Fluorescent light at relatively lower illumination intensities (0.2 mW/cm2 to 0.5 mW/cm2) were used for the investigation of TCO-less C-DSSC performance with and without reflector geometry. Furthermore, the DSSC performances were analyzed and compared with the commercially available amorphous silicon based solar cell for indoor applications. PMID:27451601

  15. Bragg reflection program

    International Nuclear Information System (INIS)

    This user's guide to the Bragg Reflection Program (BRP) is in the nature of an informal report. The general purpose of BRP is to scan a series of Bragg reflections automatically in order to obtain profiles and integrated intensities. The program is used in conjunction with the SUPERVISOR and READ packages, and the procedures for using it are similar to those for the Triple-Axis Control program. All the general features of the system, SUPERVISOR and READ packages as described in the Spectrometer Control Systems User's Guide are preserved. The presentation assumes that the reader is familiar with these. Sections are given on the READ package, execution and use, error messages, and output. A few sample problems are shown. (1 figure) (U.S.)

  16. Service Learning Reflection Journal

    OpenAIRE

    Sass, Margaret

    2013-01-01

    Service-Learning, a subset of service-engagement, is a course-based, credit-bearing educational experience in which students participate in an organized service activity that meets identified community needs; use knowledge and skills directly related to a course or discipline; and reflect on the service activity in such a way as to gain further understanding of course content, a broader appreciation of the discipline, and an enhanced sense of personal values and civic responsibility. This ...

  17. Solar Features - Solar Flares - SIDS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Sudden Ionospheric Disturbance (SID) is any of several radio propagation anomalies due to ionospheric changes resulting from solar or geophysical events.

  18. Solar Features - Solar Flares - Patrol

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  19. Reflection Revisited: The Class Collage

    Science.gov (United States)

    Sommers, Jeff

    2011-01-01

    Through the regular use of what Donald Schon has termed reflection-in-action and reflection-on-action, students can learn to improve their "reflection-in-presentation," in Kathleen Blake Yancey's term. Students are often asked to do this type of reflection-in-presentation as a capstone to first-year or basic writing courses. However, a number of…

  20. Lightweight, low-cost solar energy collector

    Science.gov (United States)

    Hochberg, Eric B. (Inventor); Costen, Michael K. (Inventor)

    2006-01-01

    A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of identical tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two identical spaced anchorplates, each containing a plurality of holes which lie on the desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers which control the shape and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape.